This PDF file contains the front matter associated with SPIE Proceedings Volume 12030, including the Title Page, Copyright information, and Table of Contents.

In order to meet the needs of the interferometry fiber optic hydrophone for high-power strong coherent laser source, a narrow linewidth distributed feedback fiber laser (DFB-FL) with high-power 16-wavelength ITU channels was developed by the MOPA amplification technology. The output power of single wavelength laser is more than 10 mw, the laser linewidth is less than 2 kHz, the relative intensity noise (RIN) is less than -105 dB/Hz. By comparing with other narrow linewidth fiber lasers from NKT compony and NP Photonics compony, the performance of the linewidth of the developed laser reaches the international advanced level. It can be used as strong coherent laser source of fiber optic hydrophone and other hydroacoustic detection.

The search for low loss plasmonic metals have been a long-standing research topic in the nanophotonics community. This issue becomes even more important for two-dimensional plasmonic devices as the light-matter interaction with twodimensional materials will be significantly suppresses by metal absorption due to their atomic thickness. In this paper, we have numerically demonstrated that light amplification may be achieved in a plasmonic resonant metasurface using a lower loss metal film. Using a modified template peeling method, we found that the gold films obtained by template peeling have a better three-dimensional morphology than those obtained by vapour deposition, while the gold films obtained by template peeling have a lower relative dielectric constant imaginary part in the 400-800 nm band as measured by ellipsometric polarisation. We expect that further improvement of the fabrication method for the low loss ultra-smooth plasmonic films will lead to the demonstration of high performance two-dimensional materials plamsonic devices such as lasers or spasers.

With the development of electro-optical countermeasure equipment and military combat training needs, we propose to build a comprehensive test system. It analyzes equipment test requirements and system architecture, introduces the general composition and main functions of the comprehensive test system, and discusses the key test contents and test equipment. The integrated test system is convenient for equipment use and support personnel to monitor, evaluate and predict the equipment indicators and state, which is also providing data support for electro-optical countermeasure equipment operation, training, maintenance and management in order to continuously improve the equipment and support technology innovation.

The cooling and quantum control of the optically trapped particles is a hot topic in quantum frontier research. One of the key steps is using Kalman filter to extract the particle’s motion from noisy signals. Time delays of the Kalman filters are found in the process of signal extraction. Here the particle displacements based on the parameters of actual optical trapping systems are simulated, and the time delays of the Kalman filtering process are observed by changing the oscillation periods and the relaxation time for stabilization. The results indicate that Kalman filtering can effectively compress the noises in the displacement signal and thus improve the signal-to-noise ratio. Furthermore, as smaller the signal frequency is, larger time delays are observed in the process. It shows that the time delays should be noticed and compensated. Meanwhile, it is shown that the consuming time for signal stabilizations in the filtering process and the phase of the original signal, neither of which affects the filtering effect. These simulation results are our initial explorations for the cooling of optically trapped particles in vacuum. It would provide possible help to deal with the delay mismatch resulted from Kalman filtering and for the cooling of the optically trapped particles.

Attitude measurement is one of the core problems of celestial navigation, which is based on determining the position of star sensor in space. In order to solve the problem of optical axis pointing of star sensor in celestial navigation, the method of solving the optical axis pointing coordinate of star sensor is studied under the condition of known celestial spherical coordinates of the star and the distance between star image point and image plane center. In particular, considering the different measurement noise of each navigation satellite in the actual measurement, the existing equal-precision algorithm is improved and a weighted geometric solution method is proposed. Finally, the validity and effectiveness of these algorithms are verified by Monte Carlo simulation. The results show that the accuracy of the proposed method is greatly improved compared with the traditional method by allocating appropriate weights when the estimated measurement noise of each navigation satellite is different.

The raw coal of Ping Coal No.1 Mine is highly muddied and extremely difficult to separate, which is generally sold as power coal.In order to improve the competitiveness of the market, we tried to convert it into coking coal through coal preparation, We explored and solved the problem of high circulating water concentration caused by high sludge and deterioration of flotation index due to high ash and fine sludge, and successfully converted it into coking coal, which not only improved the economic value of the raw coal, but also improved the competitiveness of the product and the economic benefits of the enterprise are improved.

In this article, to investigate the luminescent properties of rare-earth ion doped and transition metal doped cuspidine glasses, the transparent Ce³⁺ doped and Ce³⁺/Mn²⁺ co-doped 3CaO-CaF₂-2SiO₂ glasses were prepared. The luminescence emission spectra, excitation spectra and luminescence decay curves were recorded and analyzed. The tunable broadband emission was obtained from Ce³⁺ doped 3CaO-CaF₂-2SiO₂ glasses. With the increasing of Ce³⁺ contents, the luminescence intensity shows concentration quenching when the doping concentration is 0.5 mol% while the lifetime decrease. The energy transfer between Ce³⁺ and Mn2+ is confirmed in Ce³⁺/Mn²⁺ co-doped 3CaO-CaF₂-2SiO₂ glasses from emission spectra and decay curves of the co-doped glasses samples. The emission color of Ce³⁺/Mn²⁺ co-doped 3CaO-CaF₂-2SiO₂ glasses can be tuned from the blue to purple by adjusting the concentration of Mn²⁺ ions.

Carbon dots (CDs) not only inherit the advantages of good biocompatibility and abundant raw material sources, but also exhibit excellent optical properties. CDs possess important research significance and application prospects in materials science, biomedicine, and catalytic degradation. In this paper, CDs were prepared from dandelions mixed with boric acid, urea, and norfloxacin respectively. We investigated the effect on the degradation efficiency of methylene blue (MB) using boron, nitrogen, and fluorine for co-doping CDs under solar light. Results show that nitrogen-doped CDs can improve photocatalytic degradation rate up to 55% which is higher than no doped CDs. That also is the best among boron-doped, fluorine-doped, and co-doping CDs with the two or three elements co-doping.

In this paper, the effect of alkaline environment on the etching of Ti₃C₂T_x-MXene was investigated and its morphology, structure and electrochemical properties were characterized. The results show that the conductivity of the Ti₃C₂T_x-MXene Solution obtained by aqueous washing reached 4.40 μS/cm, which was the highest relative to that of the Ti₃C₂T_x-MXene Solution obtained by adding NaOH, NH₃·H₂O and NaHCO₃ alkaline substances. However, the addition of excess NH₃·H₂O as well as NaOH introduces hydroxyl functional groups thereby affecting the electrical conductivity of Ti₃C₂T_x-MXene.

This paper is based on the measurement of projectile motion attitude demand during the half constraint period of artillery. A high precision missile-loaded laser with high impact resistance, light weight and high temperature resistance is developed. Meet the requirements of high performance test system.

Global warming is a severe test facing the international community. As a serious greenhouse gas, the emission of SF₆ has been restricted. In recent years, more and more experts and scholars have turned their attention to alternative gases of SF₆. C₅F₁₀O(GWP<1) as an alternative gas is investigated by scientists due to good dielectric properties and weak greenhouse effect in recent years. In the first part, this review introduced the background of SF₆ and C₅F₁₀O. In the second part, we elaborated on four synthetic methods of C₅F₁₀O. Trifluoroacetyl fluoride is the key raw material, CsF is an important catalyst. In the third part, the review presented the dielectric and arc interruption properities of C₅F₁₀O and its mixtures. The addition of O₂ can increased the breakdown voltage of gas mixture. Finally, the decomposition mechanism and products of C₅F₁₀O，C₅F₁₀O/CO₂ or C₅F₁₀O/N₂/O₂ gas mixtures are reviewed.

In order to effectively remove nitrogen from wastewater with low C/N ratio, carbon cloth bipolar plate electroenhanced bioreactor (CBEEB) was proposed, which achieved good nitrogen removal efficiency. However, the influence factors and current response of nitrogen removal were not deeply studied, which was not conducive to the dynamic optimization of reaction conditions. In this paper, further research on this problem was carried out. In the beginning of the experiment, the influent COD and ammonia nitrogen concentrations were controlled to 150mg/L and 30mg/L respectively (C/N = 5:1) under the condition of 0.7V applied voltage, 24h intermittent periodic water exchange, each time the water exchange volume accounts for 1/3 of the reactor volume, and the aeration rate was 40mL/min.In the final stage, the influent concentrations of COD and ammonia nitrogen were 550 mg/L and 367 mg/L (C/N =1.5:1) respectively. The experimental results showed that the COD concentration in the influent was 395.8mg/L, and the effluent concentration was only 74.5mg/l, the removal rate reached 81.2% on the 12th day. On the 11th day of operation, the removal rate of ammonia nitrogen also reached the highest of 80.1%. At the same time, the change of current also fluctuated with the treatment effect in the whole operation cycle. When the treatment efficiency reached the highest, the current value increased, and vice versa. CBEEB system can provide a reference for the treatment of wastewater with low C/N ratio.

The photocatalyst of BP/Bi2MoO6 was prepared by the coprecipitation method to form a direct Z-type hetero-junction. The prepared samples were characterized and analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM) and UV–Vis diffuse reflectance spectroscopy (DRS).The photocatalystic activity efficiency of the BP/Bi2MoO6 composite materials was investigated by photocatalytic degradation of rhodamine B (RhB) under visible sunlight. The experimental results showed that the catalyst photocatalytic activity was optimal. When the doping content of BP was 1%, the photocatalytic activity of this catalyst was optimal and the degradation efficiency of RhB reached about 91% within 120 min, which was about 78% higher than that of pure Bi2MoO6. Electrons play a leading role in the entire photodegradation reaction system, with a contribution of about 80.8%.

High temperature superconducting cable uses liquid nitrogen cooling auxiliary system to cool the superconducting cable body to the superconducting critical temperature, ensures that the cable meets the designed current-carrying capacity, exploring the physical and mechanical properties of rock and soil under the freezing and thawing cycles of liquid nitrogen possesses an important practical significance and engineering practical value. In order to explore the changes in shear strength parameters and internal pore characteristics of Shanghai Clay under different freezing and thawing cycles of liquid nitrogen, indoor direct shear tests and mercury intrusion tests were carried out for Shanghai remolded clay that had undergone different freezing and thawing cycles. The results showed that the Shanghai Clay had undergone extremely low temperature after freezing and thawing, its cohesive force gradually decreased while the internal friction angle showed an increasing trend. the mercury intrusion tests results show that the freezing and thawing of liquid nitrogen makes the pore ratio of small pores and ultra-micropores of soil samples decreased, while micropores increased, the internal pore diameter shows a trend that concentrated in the category of micropores; more contact areas were created as a result of the small pore diameter and void ratio decreased, resulting in the increase of soil friction angle. The reduction of micropores and ultramicropores reduced the cementation between clay particles and the cohesive force generated by electrostatic attraction.

Laser diode interferometers, which have the advantages of low-cost and miniature, can be applies as the position sensor of the micro/nano positioning stage for on-line displacement measurement. However, the accuracy and the stability of the laser diode wavelength are poor, which will significantly affect the measurement accuracy of the laser diode interferometer. Therefore, in order to improve the measurement accuracy of the laser diode interferometers, a wavelength measurement method based on the principle of the diffraction grating and a wavelength stabilization method based on the automatic temperature control are proposed to real-time correct and stabilize the laser wavelength in this paper. A group of experiments are conducted to demonstrate the feasibility of the proposed methods.

As the population grows, demand for food is rising. However, the food harvest is not very stable because of adverse factors such as insect disasters and drought. To ensure adequate food production, people used pesticides to ensure the growth of crops. Many crops have been harvested, followed by varying degrees of pesticide problems, leading to important global health problems. Although traditional technologies such as high performance liquid chromatography (HPLC) and mass spectrometry (MS) have traditionally been used to detect such food pollutants, they are relatively expensive, timeconsuming, and labor-intensive. For this reason, a simple and sensitive method for the detection of pesticides is urgently needed. Electrochemical biosensors are emerging devices to meet this expectation because they represent reliability, simplicity and cheapness. In this review, we discussed the use of electrochemical biosensors to detect four categories of pesticides and further summarized the advantages of such a detection method for detecting pesticides.

As one of the popular and characteristic optical biosensors, colorimetric biosensors play an important role in drug detection, food processing, and industrial quality inspection. The side effects such as allergy caused by the abuse of antibiotics and the enhancement of bacterial drug resistance make this topic attract increasingly public attention. This work summarizes and analyzes the contribution and challenges of using colorimetric biosensors to detect antibiotics in past academic research. Compared with traditional antibiotic detection methods, the colorimetric biosensor presents high specificity, high efficiency, and easy operation. Therefore, it will have great prospects in antibiotic detection in the future.

Focusing on the global energy crisis and facing major national needs, scientists explore the field of hydrogen production materials by electrolysis of water. As a new catalyst material, MoS₂ shows high catalytic efficiency in the electrolysis of water for hydrogen production. It, therefore, has the potential to replace Pt precious metals as a catalytic material in hydrogen precipitation reactions[1]. MoS₂ is based on nanomaterials and its catalytic activity and intrinsic properties can be improved by modulation of the morphological structure. The process of preparing MoS₂ in nanospheres, amorphous, bread-shaped and flower-shaped MoS₂ is discussed in this study. The effect of adding surfactants or other solvents to the synthesis on the morphological structure is investigated in comparison with the efficiency of hydrogen precipitation. Finally, ideas for improving the catalytic efficiency are presented and future developments of MoS₂ materials are foreseen. Studies have found that the morphology and structure of MoS₂ can be changed by solvents and surfactants. The catalytic activity of nano-microsphere and flower-like is higher than that of bread-like MoS₂.

Electrocatalytic water splitting into hydrogen is one of the most promising methods to deal with global energy crisis and greenhouse effect. However, the conversion efficiency is greatly limited by the sluggish charge transfer, and severe agglomeration of catalysts. Graphdiyne (GDY), consisting of both sp- and sp2-hybridized carbon atoms in a 2D planar structure, possesses distinct chemical and physical properties, like direct bandgap, natural uniform pores and superior conductivity, which makes GDY an ideal support to inhibit the agglomeration of the catalyst and accelerate the charge transfer. In this review, various graphdiyne-supported electrocatalysts used to splitting water into hydrogen and oxygen, are described. The future challenges of GDY as catalyst support are also outlined. Such a comprehensive summary not only provides a profound understanding of GDY-supported catalysts for electrochemical energy conversion, but also opens up promising channels for catalysts design.

HgCdTe is the most widely used material for infrared detectors’ fabricating, basically because of its superior photonelectronic characters. As the fabrication process is comparatively simple and the cost could be very low, HgCdTe photoconductive (PC) detectors still receive widespread applications in many detection fields. For HgCdTe PC detectors, ion beam etching (IBE) is the most commonly used technology for detectors’ micro mesa isolation. Ion beams used for etching have certain amounts of energy that would induce some etching damages being processed and also raise the temperature of HgCdTe material. These effects would impact the photon-electronic characters of HgCdTe PC detectors finally obtained. In order to improve the performance of HgCdTe PC devices, we may fabricate them at an extreme-low temperature (ELT). In this paper, we studied some characteristics of argon-ion (Ar⁺) beam etching at ELT. Furthermore, we not only successfully prepared long-wavelength (LW) HgCdTe PC devices by etching at near liquid nitrogen temperature (LNT), but also compared the testing performances with those obtained by etching at near room temperature (RT).

Using carbonyl iron powder with particle size of 3~5 as raw material, the carbonyl iron powder was treated by ball milling process, and the flake modified wave absorbent was prepared. Its electromagnetic parameters were analyzed, and its absorbing performance was predicted by simulation.Scanning electron microscopy (SEM), X-ray diffractometer (XRD) and vector network analyzer (VNA) were used to characterize the micromorphology, phase and electromagnetic parameters of samples at each stage, and the effects of ball milling process on the absorption properties of carbonyl iron powder were studied.The results show that the morphology of carbonyl iron powder is lamellar, the crystallinity of the original carbonyl iron powder is weakened, and its coercivity is increased.The anisotropy of the flake carbonyl iron powder is enhanced, the surface contact between the iron powder particles is increased,the electromagnetic parameters of the sample are improved.The minimum reflectivity of carbonyl iron powder moves to low frequency by ball milling.After ball milling for 3h, the sample has the strongest absorption performance. The reflection loss of the 3mm thickness material is less than -10dB in the wide band range of 3.45-6.3GHz.

Pathogenic bacteria bring serious harm to the human body and environment, and thus developing diverse detection methods for monitoring these pathogenic bacteria is still urgent. For this reason, it is very necessary to create a series of advanced optical biosensors to detect all kinds of pathogenic bacteria. Optical biosensors, here, are widely used for high sensitivity, excellent specificity, low cost, ease of handling, or other inherent advantages. In this paper, two classic optical biosensors, including colorimetric biosensors and fluorescence biosensors, are outlined in the field of pathogenic bacteria detection. In details, for the detection of pathogenic bacteria in colorimetric biosensors, colorimetry is divided into two categories based on plate and solution. To detect pathogenic bacteria in fluorescence biosensors, different biosensors are summarized, where a large number of fluorescent materials are used to create different fluorescence biosensors. In a word, the progress and limitation of both colorimetric biosensors and fluorescence biosensors in recent years are reviewed. The development direction of these optical biosensors has a broad prospect for the detection of pathogenic bacteria.

In the far-infrared (THz) field, single-walled carbon nanotubes (SWCNTs) are promising candidates for room-temperature and self-powered thermal detectors due to their low specific heat capacity, high stability, relatively large Seebeck coefficients, and the ability to be doped diversely. Especially when the nanotubes are aligned, the photoresponse becomes polarization-sensitive. In this work, we integrated a bowtie antenna stereostructure with a horizontally aligned SWCNTs film to generate new resonance modes and gain mechanisms to improve the polarization extinction ratio (PER) and the response of carbon nanotube far-infrared detectors. While the antenna size changes, we can get PERs higher than 6481 from 0.5THZ to 1.5 THz.

The web light-gauge steel system is a new type of steel structure, which has a good application prospect. However, in practical application, the problem of large opening in the wall often leads to a large opening ratio in structure, which has a negative impact on the structural safety. In this paper, according to the characteristics of the light-gauge steel structure, using ABAQUS finite element software and reasonable simplified modeling method, the validity of the model is verified by modal analysis, and the natural vibration period and modal calculation results of the structure are obtained, and the calculation results are consistent with those in the literature. The modal analysis and time history analysis of the structural model with different opening ratios show that: with the increase of opening ratio, the natural vibration period of the structure is approximately 1:1 linear growth, and the displacement growth is slow first and then fast, shows a critical change point. Based on the analysis results, reasonable design suggestions for different seismic fortification intensity regions are put forward.

Reclaimed asphalt pavement (RAP) has been increasingly recycled and applied to asphalt pavement engineering over the past decades. However, aged asphalt binder in RAP may lead to poorer low-temperature performance of the recycled asphalt concrete. To effectively and accurately evaluate the low-temperature performance of recycled asphalt binders, this paper investigates the low-temperature rheological properties of aged binder, virgin binder and recycled binder through the bending beam rheometer (BBR) test. By means of the MATLAB software, the Burgers model and Christensen- Anderson-Sharrock (CAS) model were used to fit to the BBR test data of the three binders at different test temperatures. The results showed that the recycled binder possessed superior low-temperature performance. Both the Burgers and CAS models performed well in fitting the measured creep stiffness data and thus can be well used in analyzing the BBR test data.

The structural, electronic, elastic and thermodynamic properties of aluminum were investigated using the first principles method based on density functional calculations in the region of 0GPa~100GPa. The unit cell volume and atomic positions were optimized with generalized gradient approximation (GGA), all calculated properties are in excellent agreement with the available experimental results, which imply the reliability of the present calculation method. The results show that aluminum is structural, mechanically and dynamically stable in the region of 0GPa~100GPa. With the increase of pressures, the cell parameter and cell volume of aluminum decrease, charge density between atoms increase. The bulk modulus, shear modulus, Young’s modulus and Poisson ratio are estimated by Voigt-Reuss-Hill approach. The B/G values and Cauchy pressures indicate aluminum possesses ductility, the ductility properties of aluminum enhance with increasing pressures. The heat capacity of aluminum increases with temperature at constant pressure while decreasing with pressure at constant temperature.

Asphalt ages gradually in the process of road construction and service due to the action of heat, oxygen, ultraviolet, moisture and other natural environmental factors. As a sustainable technology, the recycling of the aged reclaimed asphalt pavement (RAP) can bring significant environmental and economic benefits. During the recycling of RAP, the regeneration of aged asphalt is the key to guaranteeing the performance of recycled RAP. Based on a heavily damaged asphalt pavement in Dalian, China, this study evaluated the performance of the aged asphalt extracted and recovered from the RAP of this pavement, and several performance tests were performed on the obtained aged asphalt. By analyzing of its aging mechanism, three regenerating methods were adopted, and the performance of the three recycled asphalts was tested and compared. In such a manner, the regeneration effects of the three methods were objectively evaluated and the optimal regeneration approach was rationally determined.

Multi-walled carbon nanotubes (MWCNTs) have received increasing attention as prominent candidates to reinforce cement-based composites. In this study, the combination of ultrasonication and surfactants was used to disperse uniformly MWCNTs in aqueous solution. Especially, the surfactants were proportionally composed of sodium dodecyl benzene sulfonate (SDBS) and polyvinyl pyrrolidone (PVP). Reactive powder concrete samples with different MWCNTs content were prepared, and their mechanical performance and microstructure were also evaluated. The results show that the synergistic effect, provided by anionic SDBS and nonionic PVP, is effective to achieve stable dispersion of MWCNTs. The flexural strength and compressive strength were increased by 8.5% and 15.4%, respectively, when 0.10 wt% MWCNTs were added. Moreover, scanning electron microscope (SEM) revealed that the uniform dispersion of MWCNTs in matrix was further confirmed, and the porosity of cement composites with the addition of MWCNTs was decreased measured by mercury intrusion porosimetry (MIP) results. MWCNTs can reduce internal drawbacks and restrain cracks propagation at nanoscale level, thus improving the microstructure and mechanical properties.

A number of unusual properties of As/PtSe₂ vdW heterostructure, such as geometric structure, optical and electronic properties, are explored by using first-principle calculation method. The results show that band gap of As/PtSe₂ vdW heterostructure is 0.942 eV and displays type-II energy band structure, which can effectively curb reassemble of electrons and holes, which is almost consistent with the properties of semiconductor materials. In addition, the charge transfer between As and PtSe₂ monolayers is 0.0474 |e| and the interface decreased by 3.49 eV. Furthermore, the As/PtSe₂ vdW heterostructure shows ultra-strong light absorption ability in both visible and infrared regions, indicating that As/PtSe₂ vdW heterostructure has hidden purpose in photoelectric devices and photocatalysis.

The combination of concentrators with solar modules is a feasible approach to largely improve the power output of the photovoltaic system while introducing almost no extra cost of materials. In this work, cadmium telluride (CdTe) low concentrator solar cells (LCSCs) were assembled to increase the power output and reduce the cost of per unit area. Devices with and without concentrator were thoroughly characterized and the mechanism of charge transportation in CdTe LCSCs was analyzed. By integrating a ×4 optical concentrator with CdTe solar cell, the short circuit current (ISC) and power output were increased by 3.15 and 3.07 times respectively.

In this paper, through experimental research on the fire resistance performance of substation building fire-resistant exterior wall panels, a substation wall material with a fire resistance limit of 3 hours has been developed. It meets the requirements of optimal weight per square meter of wallboard and is economical and applicable, meets the needs of substation construction, and provides more wallboard options for the enclosure wall materials in prefabricated substations in my country.

Water glass material is the main material to prevent and extinguish fire, but ordinary water glass gel is easy to lose water, weak compressive strength, poor fluidity, high cost and so on. In order to solve the above problems, in this paper, the common water glass gel was modified by adding new polymer water absorbing material, plasticizer and sodium bicarbonate. The results show that the optimum ratio of water, sodium bicarbonate, super absorbent resin and β- cyclodextrin is 3000:200:60:5, and the water retention and plastic effect of the gel material is the best. Compared with ordinary water glass gel, the water retention and compressive strength of the new plastic gel are significantly enhanced, which solves the problems existing in common mineral water glass gel.

Intensive study on the system noise of infrared detection system in optical satellites could provide an important for the detection performance research and system design. The source of system noise of the infrared detection system in optical satellites is analyzed and the models of system noise including electronic noise, background noise and optic system noise are constructed. Firstly, the electronic noise model is built based by comprehensive analysis of system equivalent power and scan parameters; then, the earth and atmosphere background noise is established on the basis of the Combined Atmospheric Radiative Transfer software; lastly, the optic system heat radiation noise is studied using blackbody radiation theory. On the basis of those models, the electronic noise, background noise and optic system noise are studied, furthermore, the rule by which the system noise varies according to the changes of temperature and the influence on system noise of each noise source is studied. The results show that, firstly, the optic system noise could be ignored when the system temperature blowing 250K; secondly, the electronic noise is the primary source of system noise at 2.7μm and the background noise is the primary source at 2.7μm and 2.85μm4.19μm.

Titanium aluminum alloy has many excellent properties and is widely used in various fields, especially in the manufacture of aircraft engines.

High-strength titanium-aluminum alloy is an indispensable foundation for the development of the aviation industry. Grain refinement, as an important means of strengthening the performance of titanium-aluminum alloy, can provide the strength of the alloy. In this paper, several methods for refining the solidified structure of Ti-Al alloys have been studied and discussed, and three methods for refining grains have been found: 1. Adding refiners such as boron. 2. Rapidly solidify the alloy 3. Applying electromagnetic pulse field or ultrasound. In addition, the refinement mechanism of boron was studied, and it was found that when the boron content is 0.8% and 1.5%, the alloy has the characteristics of equiaxed crystal solidification. It has also been found that the grain size is a function of the cooling rate. Finally, this article looks forward to the future research on the refinement of the solidified structure of titanium and aluminum alloys.

Aiming at the problem that the error modulation effects are affected by the angular motions of the vehicle in the dual-axis rotational laser gyro inertial navigation system (INS), a vehicle angular motion isolation method based on attitude feedback is proposed. Based on the error equations of INS, the principles of error modulation in rotation process are analyzed. Then the relationships between the navigation results and the controlled angular velocity imposed on the rotating mechanism are established. Finally, simulation models of angular motions with various forms are established. Simulation results show that this method can effectively isolate the angular motions of the vehicle and reduce the influences of the angular motions on the rotation modulation. The navigation accuracy is significantly improved.

Nanoelectromechanical Switches (NEMS) is an emerging switch technology, and it can be applied to replace current metaloxide switches in some fields. Its unique operating principle compared to conventional switches brings advantages in some specific conditions, such as operation under extreme environments. As the CMOS-based electronics reaching their limit on certain aspects like power consumption, footprints, and operating frequencies, the NEMS may be able to become a potential solution with the potential to replace CMOS in some applications. In addition, the NEMS can be a complement to CMOS in other situations. However, NEMS itself is also facing some challenges such as the advantage of CMOS technology in manufacture, as well as emerging new metal-oxide-semiconductor technology such as FinFET. In this article, Nanoelectromechanical Switch's potential advantages over conventional metal-oxide-semiconductor, such as power consumption, reliability, and operating frequencies, are being analyzed. The challenges when applying NEMS were discussed. Furthermore, possible solutions are also proposed. According to the research result, NEMS has the following advantages: lower power consumption, higher reliability, and better-operating frequencies. Challenges are mainly the reliability issue, problems with manufacturer standards. A possible solution is the CMOS-NEMS combination.

Based on the role of photovoltaic power generation (PPG) in solving environmental pollution and resource depletion in the energy sector, this paper studies the investment benefits of PPG. Based on the analysis of the cost and benefit of PPG, the connotation of the environmental benefits of PPG was analyzed, and the investment benefit evaluation model of PPG projects considering environmental benefits was constructed. A case example is analyzed through actual PPG projects. The results show that without considering the environmental value, the net present value of the example project is positive, and the internal rate of return is greater than the capital cost, indicating that the project is economically feasible. After considering the environmental benefits, the net present value of the project has increased by 62.59%, and the internal rate of return has increased by 1.25%, indicating that the investment benefits of the project have been significantly improved after the introduction of environmental benefits.

In order to solve the design and application problems of photovoltaic bracket foundation under red clay geological conditions in the southwest karst area, in this paper, a micro cast-place pile was optimized, and its bearing capacity, economy and surface disturbance of micro cast-in-place piles were analyzed through theoretical calculation and static load test. The results show: the micro cast-in-place pile has good adaptability and can be widely used in similar projects. Compared with similar geology and same load engineering sites, the material cost and surface disturbance of the micro cast-place piles have been reduced by about 12.25%~ 59.08% and 10%~60% respectively. In engineering design of micro cast-place pile, the vertical pull-out bearing capacity is calculated by the revised code method, the horizontal bearing capacity is taken by the critical load value determined by the test or the M value corresponding to the critical load of the similar project, which is used in engineering design as a control index with higher safety and economy.

The cabin system is a part of a civil commercial aircraft that directly provides service to the end user, the physical environment such as sound, light and service facilities which enrich the travel experience. Specifically, it includes cabin lighting system, passenger address and cabin interphone system, in-flight entertainment system, cabin external communication system and possible adopted system which will directly enhance the satisfaction. The application of system engineering thought to carry out the Top-down laser projection system reduces the project risk and avoids the cabin potential safety hazard. This paper will study and summarize the method of cabin design based on system engineering thought.

At present, there are few research on thermal effects of objects irradiated by incoherent directional light. Two methods which are experiments and numerical simulation are adopted to study the transient temperature field of the cotton-padded jacket irradiated by incoherent directional light. Firstly, based on 3D transient heat transfer equation, the transient temperature field model of the cotton-padded jacket which are irradiated by incoherent directional light is established. Secondly, when the initial condition, boundary condition and light parameters have already been set, the module of heat transfer in solids which is from the COMSOL Multiphysics 5.5 software is used to calculate the transient temperature field of the cotton-padded jacket. Thirdly, in order to verify the accuracy of numerically calculating results, the experiments which the incoherent directional light irradiates the cotton-padded jacket are done. The infrared images of jacket at different irradiation time are recorded by a long-wave infrared camera. Finally, the temperature fields of the jacket obtained by numerical calculation and experiments are analyzed. The common points between the two results include: the temperature of the jacket increases with the increase of irradiation time; the temperature of the jacket at the light spot center is the higher, while the temperature at the spot edge is lower. The different points between the two results include: at the same irradiation time, the temperature values of the two results are different; when the irradiation time is more than 20 s, the relative error of the two results is less than 10%. The analysis results show that the numerical calculation model of the temperature field of the cotton-padded jacket irradiated by incoherent directional strong light is reliable. The model can be used to numerically calculate the temperature field of different objects irradiated by incoherent directional light under different conditions.

We numerically studied a simple and novel graphene-based dielectric microcavity narrowband perfect absorber. By electrically modulating the graphene Fermi level and critical coupling theory, our absorber achieves 100% perfect absorption at 8.0 μm in the mid-infrared, and the FWHM (full width at half-maximum) of the absorption peak is only 21 nm. We use the optical constants obtained from experimental data, including the mobility and surface conductivity of graphene, so the results are more applicable. In addition, the relatively simple structure of the dielectric microcavity graphene structure has a high tolerance for manufacturing defects.

Based on the calculation model established in this paper, the radiation temperature of a thermal target attached a thin film on its surface was calculated during sun exposure. From the results, stealth effects of the film with different parameters of the emissivity were investigated. For a thermal target, the low emissivity film has a good stealth effect in 8~14μm. However, due to the influence of solar radiation, it is difficult to achieve stealth in 3~5μm by using a low emissivity film alone. Then some other methods, such as insulation, cooling and so on, have to reduce the radiation of the thermal target for infrared stealth in this band. Moreover, these methods can also reduce the radiation of the thermal target in 8~14μm, so requirements for the emissivity of stealth film in this band can be lowered.

Container shipping of dangerous goods can effectively reduce the damage rate of dangerous goods. However, due to the physical and chemical properties of dangerous goods, there are many safety matters that need to be paid attention to when the containers are stored in the yard, especially the temperature. Using infrared technology to monitoring the temperature of container which loaded with dangerous goods in port container yard supplies an effective method for the safety management of Port Container Yard.

Reflectivity is an important indicator in the development process of absorbing materials. However, for low frequency, the RCS reduction of materials with the same reflectivity is very different when they are applied to stealth aircrafts. It is impossible to comprehensively measure the absorbing performance of materials only using reflectivity indicators. In the research process, using the reflectivity and surface wave calculation formula, the difference of traveling wave suppression coefficient under the condition of equal reflectivity is found theoretically, and the accuracy of the conclusion is verified from the perspective of electromagnetic simulation. The research shows that in the relative dielectric constant set with equal reflectivity -10dB, the thickness of 30mm, frequency of 0.5GHz, the combination of the maximum suppression of traveling wave is at the position of the minimum value 20.93 of the real part and the middle value 7.89 of the imaginary part.

The infrared spectral emissivity of selective radiators varies with wavelength. Selective radiators have good application prospects in solar energy utilization, camouflage, radiation refrigeration and other fields. In this paper, a selective radiator which has low emissivity in mid-far infrared band is designed by using frequency selective surface. The electromagnetic characteristics of the selective radiator in mid-far infrared band are calculated by using HFSS simulation software. Through calculation, it is found that the designed selective radiator has high reflectivity and low transmittance for the incident electromagnetic wave at 3-14μm band. In this paper, the reflection and transmission characteristics of the selective radiator to electromagnetic wave were calculated at three incident angles of 0^o, 15^o and 30^o. The calculated results show that with the increase of incident Angle, the band stop filter bandwidth of the selective radiator increases, and the resonant wavelength moves to the short-wave direction, but the variation range is not large. The filtering characteristics of bands above 6μm show better band resistance with the increase of incidence Angle.

Based on the finite element software ABAQUS, this paper uses a three-dimensional cohesive element to simulate the interface between the skin and the core, and establishes a prediction method for the ultimate bearing capacity of a composite sandwich cylindrical shell under hydrostatic pressure. The numerical calculations are in good agreement with the experimental results, which verifies the accuracy and feasibility of the numerical models and calculation methods. Furthermore, the influence of core modulus of floating/sound absorbing composite sandwich cylindrical shell on bearing characteristics was studied. Based on the integrated calculation of Isight and ABAQUS, the optimization goal is to improve the critical instability load, and the surface winding method of the composite sandwich cylindrical shell under deep water static pressure is optimized to obtain the optimal surface winding angle. The research results have certain reference value and guidance for the underwater application and research of composite sandwich cylindrical shells.

Under the thermal treatment, crystallization of fused silica glasses was observed and investigated in detail. Normally, the crystallization of the transparent fused silica glass does not occur with the temperature less than 1200°C even 1380°C. In this paper, cristobalite was present in fused silica by contacting with the corundum plate under the annealing temperature of 850°C. The cristobalite phase transformation from amorphous into polycrystal fused silica glasses was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The crystallization mechanism of the fused silica glass was investigated further. Energy dispersive spectroscopy (EDS) was used to detect impurities of the fused silica glass, and the elements, such as sodium, potassium, aluminum , have been observed. The thermal diffusion process of impurity elements from the corundum plate to the fused silica glass was verified with the X-ray photoelectron spectroscopy (XPS) technique. In view of impurity elements detected by EDS and XPS, multi-impurities induced crystallization of fused silica glasses has been quantitatively analyzed in detail. The research result in this paper can shed light on understanding the mechanism of crystallization and eliminate devitrification of the silica material with the thermal treatment.

Terminal-sensitive projectiles pose a great threat to armored targets in modern battlefields. The active jamming method based on waveform decoy can effectively interfere with millimeter wave radiometer of terminal-sensitive projectile. On the basis of the dynamic process of the terminal-sensitive projectile's falling scanning, a method for calculating the position of the explosively formed projectile of the terminal-sensitive projectile based on the dynamic target is proposed. The jamming signal power received by the terminal sensitive projectile at different falling heights is simulated and calculated. Combined with the threshold power of target recognition and the dynamic compensation relationship, the landing position of the explosively formed projectile of terminal sensitive projectile is obtained, and the influencing factors of the landing position are analyzed. The simulation results provide an important reference for the technical index design of jammer.

Stress state of soil in the trench wall will be influenced when the trench excavation is adjacent to the existing shield tunnel, which will affect the stability of the slurry trench. In this paper, 2D limit analysis of slurry trench stability was performed to investigate the influence on the existing shield tunnels on the stability of adjacent slurry trench. The influence mechanism of the existing tunnel was analysed. The safety factor of the slurry trench under different conditions were compared. Existing shield tunnel will decrease the stability of the slurry trench. The safety factors of the trench increases with the increasing the tunnel spacing and it would be gradually improved with the increase of the reinforcement depth and the shear strength of the reinforced mixing pile.

Power plant solid waste fly ash was successfully modified by pickling ferrous sulfate and impregnated to obtain ironloaded fly ash. The structure and surface properties of the obtained compound were characterized by X-ray diffraction (XRD), X Ray Fluorescence (XRF) and Fourier-transform infrared spectrometer (FTIR). The XRD pattern shows that the iron (Fe) elements were loaded on the fly ash in the form of ions, and the iron content (taken as Fe₂O₃) of the modified fly ash increased from 11.5% to 19%. The Iron-loaded fly ash was used to catalyze heterogeneous Fenton oxidation at a high concentration of p-chlorophenol solution (7000mg/L), and the main experimental results were as follows: non-modifies fly ash and iron-loaded fly ash exhibited poor adsorption effect on 7000mg/L p-chlorophenol with 3 and 7% of adsorption capacity respectively. It was found that the optimal reaction conditions using iron-loaded fly ash for fenton catalytic oxidation of p-chlorophphenol were under a pH value of 3, with a dosage of Hydrogen peroxide (H₂O₂) of 1mL/L, for an iron-loaded fly ash of 30mg/ L during 30 minutes for a degradation rate of p-chlorophenol reaching 96%. FTIR analysis results show that the active sites of fly ash and iron-loaded fly ash fenton catalyze oxidative degradation of p-chlorophenol are the triple bond and cumulative double bond regions with a wave number of 2360 cm-1.

Compared with the traditional cast-in-place construction, the general trend is that the higher the assembly rate or prefabrication rate, the higher the cost increment, which restricts the development of the assembly concrete construction. Based on the statistical analysis of the cost data of several practical projects and compared with the traditional cast-inplace construction, this paper probes into the restrictive factors such as current design codes or standards, fabrication, storage and transportation of prefabricated components, and on-site construction, this paper analyzes the main causes of the high cost of the fabricated concrete construction, and puts forward some relevant suggestions based on the practical engineering experience, so as to reasonably reduce the compressible cost increment.

Considering the losing of Lode angle factor in the transformation from three-dimensional strain to two-dimensional strain, calculations of some variables are not allowed to transform directly from three-dimension to two-dimension. The mathematical meaning of the incremental expression of the generalized shear strain is analyzed firstly. Then the problem of the addition of the elastic and plastic generalized shear strain increments and the problem of the superposition calculation of plastic work are discussed. The analysis indicates that: only if the plastic strains develop with constant strain Lode angle, the elastic and plastic generalized shear strain increments are addictive. And only if the Lode angle of the stress consists with that of the plastic strain increment, the superposition calculation of plastic work increment in two-dimensional expression is reasonable.

The characteristics of backfill loess is different from undisturbed loess. Researches on pile foundations of large thickness backfill loess sites are relatively scarce. Based on a large thickness Q4 backfill loess site, with the backfill loess depth of 25 m, the concrete strain gauges and reinforcement stress meter were arranged on the pile shafts, and the soil pressure cells were installed on the pile bottom for field load test of three test piles. Results show that: in the backfill loess layer, the piletop load is proportional to the depth of negative skin friction, and inversely proportional to the time of occurrence of positive skin friction. The depth ratio of neutral point (Neutral point depth/Loess thickness) is less than the range proposed by Technical Code for Building Pile Foundations (JGJ 94-2008). The loess collapsibility is obvious in the range of about 2/5 from the surface, and in this range, negative skin friction measured from test piles was far greater than the numerical value recommended by the Code for Building Construction in Collapsible Loess Regions (GB50025-2018). The largediameter long pile rendered as the frictional end-bearing pile, and it can give full play to the bearing capacity of soil. When the ratio of pile-top load and limit value of pile-top load reaches 0.705, the settlement of a single pile cannot be equivalent to the compression of the pile, and it should be the sum of the compression of the pile and the settlement of soil at the pile bottom.

It is a challenge to control the rheology of water-based drilling fluid at high densities. A new environmental friendly viscosity reducing agent was employed to adjust the rheology of high density water-based drilling fluid under high temperatures. This paper focuses on the study of a new environmental protection viscosity reducing agent FSJ-3 which is suitable for high temperature and high density drilling fluid system. On the basis of 2.40g/cm³ high density mud, the comparison between other viscosity reducers and the viscosity reducer FSJ-3 developed in this paper is investigated. The experimental results show that the new viscosity reducer FSJ-3 has the advantages of good viscosity reduction effect(The viscosity reduction efficiency can reach 20%), strong temperature resistance and superior environmental protection, and is applied in high temperature and high density drilling fluid with good compatibility.

The Fatamogana Mirage is a complex and changeable mirage that forms in a special environment.Starting from the formation environment of Fatamoogana, we construct the medium system of refractive index gradient change, conduct simulation experiments, and reproduce the process and scene of Fatamoogana formation, and the characteristics of the mirage and the propagation of the light in refractive index gradient are analyzed.Subsequently, based on the propagation process and mechanism of light in a variable refractive index gradient medium, starting with the monotonic changing media environment of the refractive index, this paper establishes a variety of medium change gradient models, solving the path equation of light according to the infinitesimal element method , then, using symmetric principles and classification discuss ideas，the paper establishes the propagation path model of light in a complex index gradient medium, and the light path propagation equation is calculated through the model.On this basis, the paper analyzes the propagation characteristics of light in complex refractive index gradient media, and the mathematical relationship between the observer, mirage source and mirage is calculated, which explains the reasons for the complex and changeable nature of Fatamogana mirage.Finally, the paper analyzes the significance of research results in the design of laser aiming system and radio communication communication.

The spent carbon anode (SCA) produced by electrolytic aluminum plants contains a large amount of fluoride salt electrolyte, which is harmful to the enterprises, environment and society. At present, the solution strategies of SCA produced by electrolytic aluminum plants mainly include flotation, roasting, vacuum smelting, fluidized bed technology and safe landfill, but only the flotation method does not produce toxic and harmful substances which is a relatively clean treatment method. However, in the past, the focus of flotation treatment of SCA was to separate and purify the carbon of SCA to obtain high-purity carbon as recarburizer, battery anode material or fuel, which is a waste of the separated electrolyte. Therefore, the electrolyte in the SCA is recycled by the flotation method. The best flotation conditions are obtained through single factor experiment. Then, a new flotation process of one coarse and three sweeps are adopted to improve the purity and recovery rate of the electrolyte until it reaches the highest value. Thus, the electrolyte of treated SCA can be returned to the electrolytic aluminum plant to recycle or sell. Therefore, the harmlessness, resource utilization and reduction of solid waste are realized, and the social and economic benefits of the enterprise are improved with the utilization rate of SCA increased.

The pyrolysis and coking characteristics of oily sludge were studied. Experiments were carried out in a fixed-bed pyrolysis reactor to explore the influences of heating rate, pyrolysis final temperature and residence time on coking. The coking was observed using SEM-EDS. The situation is characterized and analyzed, and the microstructure and element composition of the surface of the carbon layer are observed. The results showed that the longer the residence time, the more thorough the coking reaction proceeded. Increasing the final temperature of the reaction and reducing the heating rate would both increase the carbon content in the semi-coke.

Oil sludge wastes are generated in the processes of petroleum exploitation, storage, transportation and refining, and have been included in the list of hazardous wastes by most countries. A series of strict standards was formulated to limit the release of pollutants in hazardous waste in China. The firms will be subject to economic punishment or even legal sanctions if their discharge exceeds the limits. The treatment technologies of oil sludge, such as centrifugation, solvent extraction, biological treatment, pyrolysis and incineration, have some defects inevitably. Therefore the cooperative treatment of multiple technologies is a recent trend. Synergistic treatment of oil sludge by using the existing boiler in coal-fired power plant can achieve the goal of oil sludge reclamation, innocuity and reduction, and will not affect boiler operation status and efficiency due to the low proportion of oil sludge in co-combustion. Moreover, synergistic treatment of oil sludge by coal-fired power plant can rely on the existing boiler combustion system and flue gas treatment system in the power plant. So the costs of construction and operation will be much lower than professional incinerator for combustible hazardous waste. It is suggested that synergistic treatment of oil sludge by coal-fired power plant has obvious advantages.

PM2.5 is the main cause of air pollution and hinders the sustainable development of Chinese cities. Researchers have used a variety of methods including regression analysis to find factors that affect PM2.5, but feature selection is rarely used, and there are few standard methods that can solve the problem of label learning in small data sets. The purpose of this research is to determine the important factors affecting PM2.5 environmental variables and pollutants through machine learning algorithms and regression analysis based on the "China Statistical Yearbook". In this paper, the production of general solid industrial waste significantly increases PM2.5 concentration, and the comprehensive utilization of general industrial solid waste is the most economical and feasible measure to significantly reduce PM2.5 concentration. This paper also puts forward solutions to the comprehensive utilization of general solid industrial waste.

This study aims at identifying different patterns of carbon emission for countries and regions through the k means clustering method and its' time series variation. By forming emission trend clusters, we identify different modes of emission, which can be educational for policy makers and for further research on carbon pricing. The data we use to form the clusters and discussion the indication of the result clusters are retrieved from Our World In Data, the Global Carbon Project, the United Nation, and the World Bank. As a result, we arrive at a classification result for 225 economies, which allows us to compare the carbon emission path and identify anomalies. We cross-compare the clustering results with the United Nation's classification on economic development status. We regard the cluster with the most developed economies as our cluster of developed economies based on emission situation. Based on the similarities of our clusters and the United Nation's categorization, we identify regions whose emission situations do not agree with their economic development status as defined by the United Nation.

Electric vehicles (EVs) have been an effective technology option for sustainable futures among many countries. Since 1994, the HKSAR government has been promoting electric vehicles and developing related infrastructure to encourage local people to purchase EVs, and until 2010, the number of EVs began to increase. However, it is questionable whether the large-scale use of electric vehicles that rely on the grid can help reduce greenhouse gas emission (GHG), because most parts of the world still rely on fossil fuels for power generation. The use of electric vehicles will increase the regional power supply and demand relationship, so it is necessary more fossil fuels are used to generate electricity than before. This article aims to explore the relationship between the promotion of electric vehicles in Hong Kong and Hong Kong’s greenhouse gas emission with reference to the development of electric vehicles in recent years, Hong Kong’s air quality and air pollution emissions. The results show that despite the increase in the number of vehicles and kilometres driven in recent years, there has been a significant improvement in air quality and a substantial reduction in air pollutant emissions due to the increase in the share of electric vehicles in Hong Kong.

Biological treatment is the most economical method of urban sewage treatment, but the growth and metabolism of microorganisms depend on the appropriate temperature. At low temperature, the nitrification and phosphorus removal performance of microorganisms is significantly reduced. In-depth analysis of the characteristics of the microbial community in activated sludge at low temperatures is the key to understanding the nature of low-temperature wastewater biological treatment. In this study, we selected activated sludge samples from segmented inlet AO reactors that can operate stably under low temperature (15 °C) conditions and have good denitrification and phosphorus removal effects, and analyzed the abundance and structural characteristics of microorganisms by high-throughput sequencing technology. The results show that there were more types of microorganisms in aerobic tank than in anaerobic tank, and both areas are dominated by microorganisms that degrade organic matter. The results also show that a variety of high-abundance denitrifying phosphorus removal bacteria were accumulated in the reactor, such as denitrifying bacteria Dokdonella, Flavobacterium, Runellar, phosphorus accumulating bacteria Tetrasphaera, Candidatus_Accumulibacter, Candidatus_Competibacter and other phosphorus removal bacteria.

To improve the flame-retardant performance of cotton fabrics, an eco-friendly, simple and effective method was proposed. Amino trimethylene phosphonic acids (ATMP), chitosan, complexes with copper ion were deposited to cotton fabrics via layer-by-layer (LbL) assembly. FTIR spectra suggested that the LbL coatings were successfully deposited on the cotton fabrics surface. TGA analysis indicated the LbL coatings could promote the char formation and strengthen the thermal stability when the temperature high. The results of microscale combustion calorimeter test and vertical flame tests demonstrate that the existence of the CH-Cu/ATMP coating significantly suppressed the heat release rate of the cotton fabrics and higher concentration of copper ion and more layers in coating could bring better effect of flame retardancy.

We designed and prepared a one-dimensional Mn-based metal-organic framework (26p-Mn-MOF) by hydrothermal method. The molecular structure is C₁₄H₁₀Mn₂N₂O₁₁. and this structure has the monoclinic, C2/c space group. In this work, we found that the Mn-based MOF exhibited very good catalytic performance in the process of synthesizing tetrachlorantraniliprole.

Capturing carbon dioxide produced by chemical plants and storing it in the oil reservoir can not only supplement the formation energy of the oil reservoir, but also improve the recovery rate. Based on the actual situation of the associated gas in the CO₂ injection area of an oilfield, this paper summarizes the influence of each main component on the two phase points of the associated gas through simulation calculations, and provides a theoretical basis for the setting of boundary conditions when the associated gas containing hydrocarbon impurities is reinjected. Studies have shown that as the content of light or heavy hydrocarbons increases, a two-phase zone will gradually appear. As the methane content increases, the temperature of the two-phase point gradually decreases, while propane, butane, pentane and hexane are the opposite. Compared with the pure carbon dioxide phase diagram, the two-phase point of the mixed gas containing methane enters the liquid phase region of carbon dioxide. The two phase points containing propane, butane, pentane and hexane move in the gas phase region of carbon dioxide. In particular, ethane has a small effect on the physical properties of associated gas, and when only ethane and carbon dioxide are contained, the two-phase point of the mixed gas has a low temperature and low pressure abnormal point. If the associated gas is directly reinjected, the pressure needs to be greater than 9.5 MPa to ensure that CO₂ is pressurized to a supercritical state.

The frequently severe air pollution episodes in China have increasingly gained a concern and intensive studies. Planetary boundary layer height (PBLH) is a non-negligible factor dictating the vertical dilution of near-surface pollution. However, the relationship between boundary layer height (BLH) and fine particulate matter with an aerodynamic diameter less than or equal to 1μm (PM₁) and black carbon (BC) concentration across China, is still lacking sufficient research. In this study, by using L-band radiosonde measurements at 0800 and 2000 Beijing time (BJT), atmospheric composition stations and national meteorological stations in China during the period 2016 to 2017, the relationship of PBLH with PM₁ and BC are investigated. Both BC and PM₁ concentrations exhibits seasonal variability with the peak in winter, followed by fall, spring and summer, which is opposite to the seasonal variation of PBLH. This suggests a negative correlation between PBLH and surface aerosol concentration on seasonal timescale. In terms of diurnal timescale, PM₁ is also found to anti-correlate with PBLH at both 0800 and 2000 BJT with correlation coefficient (R) of −0.13 and −0.24, respectively. Albeit the relatively strong negative correlation (R=−0.2) of BLH-BC at 2000 BJT, the PBL is almost irrelevant with BC in early morning, which could be due to the fact that the PBL is not fully developed. Low BLHs, strong atmospheric stability, weak winds and high humidity in the lower troposphere collectively exacerbate the BC concentration in China, and such similar results are obtained when the analogical analysis is extended to PM₁.

The CFG pile has many advantages, such as small settlement, simple construction. So it has been widely used as the common foundation treatment in China. However, it has been carefully used in soft soil site because of quality defects of CFG piles. Based on a highway project case of soft site treatment using CFG piles in Fujian province, the reason of the pile integrity problems is analysed, and several solving methods are proposed. The studies show that long spiral drilling technology should be better than the sinking pipe method and geobag combined with sinking pipe method in the construction process of the CFG pile in soft soil site. The research results have significant reference to the application of CFG piles in soft soil site.

The phase change material (PCM) absorbs or releases heat through its own phase change, so as to achieve the function of temperature control or temperature adjustment. At present, the building composite phase change material composed of phase change material and base material has become one of the research hotspots of building green materials. Phase change concrete made by mixing phase change materials into ordinary concrete through various methods has the advantages of energy saving, environmental protection, temperature control, etc. However, due to the special properties of phase change materials, this field still faces many key problems, such as phase change the composite method of materials and ordinary concrete, the mechanical properties and economy of phase-change concrete limit its application in the construction field. This article briefly summarizes the current situation of the preparation, performance research and application of phase change concrete, and puts forward the outlook.

In order to meet the requirements of monitoring the operation of three-span circuit, a comprehensive monitoring system of three-span circuit condition based on all-optical sensing is developed by making full use of the advantages of optical fiber sensors such as no electromagnetic interference, field passivity and easy to form sensor array. Various new optical fiber angle, vibration and temperature and humidity sensors are applied in the hardware of the system to realize the overall monitoring of the physical parameters of tower, wire and environment. Dynamic comprehensive objective weight is used to evaluate the overall operating state in software, avoiding the disadvantages of subjective weight assignment and fixed weight. The system has been tested on site and can run stably for a long time. The next phase will develop fiber optic sensors for other monitoring functions and further enrich the algorithm model.

Optical fiber end face interferometer is a high-resolution optical instrument which is mainly used to measure the geometric characteristic parameters of the fiber end face. According to the optical fiber communication principle, in this paper, we propose a comprehensive method to modeling and confirm the mechanism for the fiber insertion loss and geometric quantity correlation simulation. The lack of traceability chain of the fiber end face interferometer is analyzed, which is restricting the performance optimization of optical fiber link. The experimental results show that the method is effective and closer to the actual measurement results. Meanwhile, the optimal measurement uncertainty of the home-built traceable standard for fiber end face interferometer is less than 5nm, which the insertion loss is less than 0.3dB for easy detection while instant manufacturing. The traceable method of the interferometer improves the confidence probability of fiber end face detection. Especially, gradual application of the method is conducive to the establishment of the traceability system of fiber end face parameters and the high-quality development of optical communication manufacturing.

Many volatile organic compounds (VOCs) will be released in the process of food deterioration. These VOCs are closely related to the physical and chemical properties of the food. Its rapid detection is important to the assessment of food quality and safety. Traditional analytical methods based on chromatography-mass spectrometry have excellent detection limits and accuracy, but their sampling and pretreatment lead to time-consuming, and cannot quickly detect food VOCs. This article uses tunable diode laser absorption spectroscopy (TDLAS) technology to explore a rapid detection method for fo od spoilage based on VOCs. In this paper, a spectral absorption peak caused by ammonia gas released from spoiled beef is successfully detected, and its amplitude increases with the deterioration of beef. This study demonstrates that food spoilage can be identified using VOCs based on laser spectroscopy.

The seepage of porous dam materials in sand and gravel soil is complicated, the basic principle of seepage heat monitoring technology for earth-rock dams is introduced, and the similarities between seepage theory and heat transfer theory are summarized in this paper. A homogeneous sand dam model coupled with transient seepage field and temperature field based on Darcy equation and heat transfer equation of porous media is established by using COMSOL Multiphysics finite element software. In order to analyze the change of dam temperature field influenced by seepage field, simulation examples of dam seepage field and temperature field under different working conditions are given according to heat conduction theory and seepage theory. The example shows that seepage water temperature is the main influencing factor of temperature field in dam saturated seepage area, and the influence of environmental temperature and seepage field on dam temperature field should not be ignored. The existence of seepage field changes the spatial distribution of temperature field, that is, the change of the temperature field can reflect the change of seepage field to a certain extent. At the same time, it is also observed that heating can increase the change amplitude of seepage influence temperature.

To study the residual stress and deformation distribution of titanium alloy thick plate ultra-narrow gap welded joint by laser welding with filler wire, the ANSYS simulation software was used for the numerical simulation analysis of stress and strain of 40mm TC4 titanium alloy plate laser welded joints. The simulation result was verified with a blind-hole stress tester and 3D laser coordinate measuring device. The results show that the numerical simulation data is highly consistent with the test results. The stress distribution of single U-groove and double U-groove welded joints are different. Relatively obvious stress concentration appeared mainly on one side of the end weld of the single U-groove welded joint, while the stress distribution of double U-groove welded joint are symmetrical along the wall thickness direction. There is not much difference in longitudinal stress and transverse stress between the two kinds of grooves. The transverse contraction and angular deformation of double U-groove welded joint are smaller than that of the single U-groove, and the distribution zone of transverse residual stress on the upper surface of the single U-groove welded joint is obviously wider.

This paper studies a method of detecting and positioning the signal of identification friend or foe(IFF) signal. On the shipboard reconnaissance platform, the azimuth and elevation angle of the target are obtained in real time through the vertical and horizontal double-sided direction-finding antenna array, and the target height is grasped through the decoding of the IFF response signal C-mode and S-mode. Finally the single-station positioning is completed through the positioning algorithm. Carrying out practical experiments, the results show that the method can effectively form the target trajectory, and the positioning accuracy can reach 3% of the target distance circle error range.

In this paper, the typical working conditions during the excavation of the pit were selected as the background of the Jinan Yellow River tunnel project on the north bank, and the influence of the excavation process on the enclosure structure and soil deformation was analyzed with the help of MADIS GTS/NX finite element analysis software. Based on the analysis of the measured data on site, the measured results are compared with the numerical simulation, and some conclusions that can be used to guide the design and construction are obtained. The results show that the trends of the measured and simulated results are basically the same, and this study can provide reference for similar workhole excavation projects.

The primary components, ash contents, and fillers of a batch of plastic road speed bumps and thermal baffles for import were analyzed using multiple analytical methods (e.g., Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD)). Based on appearance characteristics and manufacturing process, the sample origin was analyzed. Such products are made using insulated polyvinyl chloride (PVC) wire and cable sheath as the raw material. Specifically, the sheath is extruded and thermoformed into plastic products in a melting furnace following cleaning and sorting. The varying dates of declaration of goods lead to different assessment opinions on solid waste. In this paper, a case study was presented, providing a reference for identification and supervision of solid wastes of recycled plastic products for import.

In order to study the dynamic response of cantilever retaining wall under earthquake action, FLAC3D numerical simulation software is used in this paper. EI Centro seismic wave is applied. On the basis of filtering and correcting the seismic wave, dynamic numerical simulation is carried out to analyze the distribution characteristics of active earth pressure under different peak acceleration, the dynamic response of acceleration along the wall height. The conclusions are as follows: the intensity of active earth pressure of retaining wall presents nonlinear distribution along the wall height, and the overall distribution is approximately "wave" shape, and the maximum earth pressure appears at the bottom of the wall, which is consistent with the position where the peak value of hilltop - physical theory appears. The total earth pressure calculated by pseudo static method is conservative compared with the simulated value, the retaining wall can still work normally under PGA = 0.4g. With the increase of the wall height, the amplification effect becomes more obvious, and the amplification coefficient reaches the maximum at the top of the wall.

A series of material parameters and production process parameters need to be determined in the design of hot in-plant recycled asphalt mixture, so as to make the pavement performance of recycled asphalt mixture meet the specification requirements. The rational determination of the aggregate gradation of the recycled mixture and the performance of the recycling agent, as critical parameters of the recycling design, has an important impact on the pavement performance of the recycled asphalt mixture. In this study, reclaimed asphalt pavement (RAP) from a seriously damaged pavement in Dalian, China was collected for recycling. Four recycling approaches with two different gradations and two different methods of recycling agent addition were designed, and the best recycling scheme was determined by a range of pavement performance tests. The results show that for the same method of adding recycling agent, the recycled asphalt mixture with the gradation close to the mid-value had better pavement performance, especially moisture damage resistance. Also, the two methods of adding recycling agent with different mechanisms exhibited basically the same performance of the recycled asphalt mixtures.

Adhesive force and adhesion energy between particle and substrate are investigated by AFM. Particles of silicon and graphite were attached to tipless cantilever to form so called particle-functioned probe, and be used to measure the adhesive force between single particle. The adhesion energy between particle-substrate was calculated according to the work for the detachment process. Adhesive force and adhesion energy of different particles and substrates were compared and analyzed.

An analytical method for determination of polyurethane content in modified polyoxymethylene (POM) by nuclear magnetic resonance (NMR) spectroscopy was established in this paper. Specifically, the samples were dissolved in the deuterated reagent, followed by being tested by 1H-NMR spectroscopy. Next, the characteristic peaks of POM and polyurethane were integrated, and the polyurethane content in modified POM was obtained by integral area ratio. This method, featuring the advantages of a high accuracy, simple and fast operations, and no nominal samples required, has a relative standard deviation of < 2%, and its correlation coefficient with actual results was 0.9993.

The radioactive deposition of nuclear explosion is simulated by Lagrange particle diffusion model. Firstly, the mesoscale meteorological prediction model WRF is used to dynamically downscale the obtained meteorological data, and then the radioactive deposition caused by ground nuclear explosion is simulated with the help of public nuclear explosion information, and the simulation results are analyzed.

Extrasolar planets (exoplanets) are the most intriguing objects in astronomy. Currently, over 4,000 exoplanets have been discovered. Among them, about 100 terrestrial ones are in habitable zones, where planetary surface conditions are theoretically suitable with the presence of liquid water. Practicing advanced equipment, technology and method, more sufficient information will enable us to analyze the habitability of exoplanet more systematically. Given the rapid development of space telescopes, capability of characterizing the extrasolar planetary atmospheres and surfaces will be achieved in near future, offering opportunities for direct observation. Ocean has much lower albedo in comparison with land, thus a terrestrial planet largely covered by oceans can be identified via photometric variability as it spins. Several models for simulating the variability have been discussed in literature, and we establish models of photometric variability for habitable terrestrial planets. In this project, oceans and growth of green plants have emerged. Feasibility of identifying habitable planets and habitable moons will be examined with these more realistic models.

We establish a theoretical model, which includes the flux from the secondary production and pulsar wind nebulae, to analyze recent positron data derived from AMS-02. We model the primary positron contribution through the sum of an average flux from distant sources and flux from the local pulsars in the ATNF catalog, while the secondary production comes from interactions of primary cosmic rays in the interstellar medium. Under certain assumptions, we include and study the most important properties of primary positrons from pulsar wind nebula in the ATNF catalog. We find consistency between theoretical model and the AMS-02 data for various analysis. The result suggests the existence and feasibility of a self-consistent interpretation for AMS-02 positron data in the field of astroparticle contributions, where data below 10 GeV are mostly produced by the secondary production, while above by pulsar wind nebulae.

Taking the cracked and unused hot-bend elbows in the same batch as the research object, comparing the wall thickness, mechanical properties (tensile, impact, hardness), chemical composition, and microstructure (metallographic, grain size) of the two elbows. Furthermore, the fracture morphology and energy spectrum analysis were carried out on the cracked elbow. The results show that the cracked elbow has a martensite structure, which leads to lower material toughness. Under the influence of a large additional bending load, it becomes the source of cracking, and finally leads to brittle fracture of the elbow.

Electrical circuit fault is one of the essential causes of electrical fires. The burning probability of wire after fault is closely related to the fire risks of the conductor itself. Molten marks generated by short circuit fault have important reference value for identifying the cause in fire investigation. The process of short circuit of wires under different overcurrent was simulated. The number of short circuit and combustion was recorded, and the short circuit molten marks were collected and observed. When the current was 16 A, there was no short circuit on the wire. With the increase of current, the probability of wire burning after short circuit was 60 % at 24A, and all wires would short circuit and burn at 48A. The metallographic structure of molten marks on the conductor end was mainly cylindrical crystal, and the spark was mostly branch crystal. However, the primary and secondary short circuit characteristics were observed under the same current condition. Therefore, the type of short circuit cannot be judged only by metallographic structure characteristics in the actual fire evidence identification.

An experiment based on physiological parameters and subjective emotional changes was designed to analyze the association of light and music. The different effects caused by music in major and minor were studied. Three mono-color light conditions (R, G, B) and warm-white in 3000K CCT and cold-white in 6000K CCT were evaluated in the same process. The experimental results showed that changes in the environment lead to physiological and psychological responses. Changes in all light colors and music had significant impacts on heart rate and respiratory rate. Analyzed with the valence-arousal of subjective emotions, it was found that music in major had a more positive influence on mood than music in minor, and white light had a more positive influence on mood than three monochromatic lights. A joint analysis of physiology and psychology found that the emotions stimulated by music in minor were most likely to be associated with blue light under low light level, while the emotions stimulated by music in major were most likely to be associated with the high correlated color temperature white light. The results confirm that light and music will influence both physiological parameters and subjective emotions.

Cheap and efficient electrocatalysts are of great importance in energy conversion and storage. Transition metal phosphorus-based catalysts have attracted much attention because of the variety of active sites and controllable structure and composition. Phosphor-based catalysts showed good electrocatalytic performance for both OER and HER over a wide pH range. Hence, the preparation and characterization methods of phosphorous catalysts were introduced in this paper, and the latest research progress in OER and HER was reviewed. Finally, the challenges and future development direction in the field of energy electrocatalysis were briefly prospected.

The gas explosion is often not single happened, dust will also participate in the formation of secondary explosions, leading to a significant increase in accidents and disasters. In this paper, the explosive process of dust deposition induced by local explosive suspended explosion of premixed gas is explored through experimental and theoretical research. The transmission law of suspended explosive over-pressure induced by local explosive deposition and the influence law of dust deposition on explosive over-pressure are studied. The results show that there is a most dangerous apparent concentration of grain dust deposited in the pipeline, at which the explosion pressure value of flour is the largest, and the peak value of explosion overpressure is the highest when the volume fraction of premix gas CH₄ is 10%. The research results will lay the foundation for the large-scale practical explosion accident prevention analysis in engineering.

In order to reveal the AE time series characteristics of coal in different damage and failure processes, a multiple damage mechanics and AE experimental system was established to study the changes of AE signals in the deformation and failure process of Bailu coal and Bailu rock under the conditions of heating, uniaxial compression and temperature pressure coupling. The experimental results show that the AE characteristics of coal in different variable damage and fracture stages are different, and the AE signal intensity produced by temperature pressure coupling is significantly higher than that of heating up and uniaxial compression. Fitting the relationship between temperature, stress and AE under three failure conditions, the results show that there is an obvious correlation between temperature, stress and AE.

In this paper, 20Ah lithium iron phosphate soft pack battery was selected as the research object, carboamide and SDS were used as additives. Through the self-designed experimental platform, the physical and chemical properties of water mist containing additives and the fire extinguishing experiment of lithium-ion battery were carried out. The results show that the water mist can effectively inhibit the fire caused by thermal runaway of lithium-ion battery, and the optimal extinguishing effect is water mist containing 1% SDS, water mist containing 1% carboamide and pure water mist. The numerical simulation of LiFePO₄ battery fire extinguishing was carried out by using FLUENT software. The results show that water mist containing 1% SDS has better fire extinguishing effect than pure water mist. By comparing the simulation results with the experiment, it is concluded that the simulation and experimental errors of each group are within 2s, which verifies the accuracy and reliability of the simulation. Through the fire extinguishing experiment and numerical simulation of LiFePO₄ battery, it provides engineering guidance for fire extinguishing of lithium-ion battery.

The emergence of Photovoltaics technologies provides new solutions to the energy crisis caused by fossil energy shortages. The development of Photovoltaics technology has also developed to the third generation, and the photoelectric conversion rate has basically reached 20%. however, how to break through has become a current difficulty. PERC solar cell and HIT battery are considered as two ways to break the existing dilemma. Although PERC solar cell has good performance on production and energy conversion rate, the photoelectric conversion rate of HIT solar cell has actually surpassed PERC batteries, and has the huge potential to replace PERC battery.

Dynamic three-dimensional surface measurement based on line-scan cameras has been developing gradually. Line-scan cameras have the advantage of high resolution and a high line rate. In this article, a measurement system based on triple line-scan cameras is presented. The measurement model is established considering the asynchronous acquisition of the same point. The point cloud optimization algorithm helps to minimize the error caused by six-degree-of-freedom vibration. Theoretical analysis reveals that the resolution of the method is approximately 0.07 mm, and the measurement uncertainty is about 0.025 mm. Experiments demonstrated the feasibility of the method.

To study the influence of glass spacing on digital image correlation measurement in the optical path, an experimental method of displacement stepping for digital image correlation measurement was designed under nine working conditions (without glass, single glass, and double glass with different spacings of 20 mm, 70 mm, 120 mm, 170 mm, 220 mm, 270 mm, 320 mm respectively). The results of digital image correlation method and dial gauge method were compared, and the measurement error and standard deviation of digital image correlation measurement under different working conditions were analyzed. The experimental results show that the variation trend of displacement measured by DIC under nine working conditions is consistent with the step change of the specimen displacement, but there exist obvious errors between the nine conditions. Based on the results of dial gauge measurement, DIC measurement results are larger, and the maximum deviation is less than 3 μm. Under the condition of without glass, the relative error of displacement measured by DIC was the smallest, with an average error of 2.92%. Under the condition of double glass spacing of 170 mm, the relative error was the largest, with an average error of 11.37%. The standard deviation of double glass condition with a certain spacing was less than that of single glass condition. In general, when the double glass spacing is within a certain range, the measurement results are more accurate and less discrete than those of single glass, and the thermal protection performance is also better.

In this paper, the influences of the motion errors of the corner cube retroreflector, not only the pitch and yaw errors but also the straightness and roll errors, on the positioning measurement accuracy are comprehensively analyzed. An error compensation model for reducing the influences of the motion errors is proposed. In addition, the effects of the motion errors of corner cube retroreflector on the quality of the interference signals is also investigated. A series of experiments are carried out to verify the effectiveness of the proposed error compensation model.