In order to solve the problem of the quantitative test of spectrum and color of aerosol, the measurement method of spectrum of aerosol based on human visual system was proposed. The spectrum characteristics and color parameters of three different aerosols were tested, and the color differences were calculated according to the CIE1976-L*a*b* color difference formula. Three tested powders (No 1# ,No 2# and No 3# ) were dispersed in a plexglass box and turned into aerosol. The powder sample was released by an injector with different dosages in each experiment. The spectrum and color of aerosol were measured by the PRO 6500 Fiber Optic Spectrometer. The experimental results showed that the extinction performance of aerosol became stronger and stronger with the increase of concentration of aerosol. While the chromaticity value differences of aerosols in the experiment were so small, luminance was verified to be the main influence factor of human eye visual perception and contributed most in the three factors of the color difference calculation. The extinction effect of No 3# aerosol was the strongest of all and caused the biggest change of luminance and color difference which would arouse the strongest human visual perception. According to the sensation level of chromatic color by Chinese, recognition color difference would be produced when the dosage of No 1# powder was more than 0.10 gram, the dosage of No 2# powder was more than 0.15 gram, and the dosage of No 3# powder was more than 0.05 gram.
The research on infrared radiant characteristics of typical target is important for the detection and recognition of
target, infrared simulation calculation and design of electro-optical countermeasures. Thus it is essential to select
appropriate test method and optimal calculation method to improve the test accuracy and reliability of infrared radiant
intensity. In this paper, three instruments including SR5000 spectroradiometer (CI, MigdalHaEmek, Israel), remote
sensing interferometer spectrometer Tensor37 (Bruker, Germany) and Image IR8325 (InfraTec Ltd, Germany)
mid-infrared thermal imager were applied to test the infrared radiant (1μm-3μm,3μm-5μm) intensity of decoy samples.
Three methods were designed based on two operational principles including direct test and indirect test. The SR5000
spectroradiometer which is able to obtain the value of radian intensity immediately is regard as direct test. The other two
instruments which deduce and calculate infrared radiant intensity according to Planck's law and Lambert's cosine law
with some preliminary tested parameters such as the response voltage,the distribution of infrared radiant temperature of
flaming samples and calibrated data by blackbody, however, are regard as indirect test. Reasons for the diversity of
experiment results were provided through analysis on the concrete measurement theory and detailed calculation methods.
Moreover, some rules and suggestions were put forward to improve the test accuracy and reliability of infrared radiant
intensity when different methods were adopted.
It is shown from experiment results that the average mid-infrared radiant intensity obtained from SR5000 was about
903W/Sr in near-infrared band,whereas Tensor 37 and Image IR8325 was about 834W/Sr and 547 W/Sr respectively. It
was proved that maximum relative of calculated results from remote sensing interferometer spectrometer Tensor37 and
results measured with SR5000 spectroradiometer is below 13%, which meet the general accuracy requirements.
Although rigorous reasoning applied, results gained by Image IR8325 mid-infrared thermal imager varied so much from
above-mentioned two instruments and the relative error is about 25%~40%. It is analyzed that complexity of the
measurement procedure and similarity hypothesis is the main reason for the errors generated.
Many investigations show that almost all detection systems operating in visible light and infrared wave bands are subject to severe performance degradation when they are used in fog. It is necessary to study the influence of fog on the photoelectric sensors so as to find out applicable countermeasures. However, it is hard to get enough meaningful data tested in nature fog. If the forming of fog can be controlled artificially, more credible research methods and experiment conditions will be acquired for studying the electromagnetic wave transmission in fog. In this paper, artificial fog was produced with the fog aerosol specially prepared with oxidant, fuel and bond. Through combustion reaction, the fog aerosol could generate artificial condensation nucleuses, which were provided with fog catalyzing capabilities and able to condense water vapor in air and produce artificial fog within several minutes. Three types of fog aerosols of different oxidant (code-named as NP/KP/LP) were prepared for the experiments. And the influence of oxidant on the photoelectric obscurity performance and the microphysical characteristics of artificial fog were researched. The photoelectric obscurity performance was tested by an IR imaging sensor and an illuminometer sensor, and the microphysical characteristics were tested by the laser granularity system. The experiment results showed that the artificial fog had good photoelectric obscurity and aerosol LP had the best. The attenuation of visible light and infrared wave band (3~5μm) in the fog were above 90%; and the attenuation of infrared wave band (8~14μm) was above 80%. Moreover, the oxidant affected closely the microphysical features of the condensation nucleus, such as the size distribution and number density. It is noticeable that while the size distributions of droplets presented similar trajectories even with different fog aerosols, the coagulation and growth rates of droplets were controlled by the fog catalyzing capabilities of condensation nucleus. Obviously, the maximal droplet concentration and the highest droplet growth rate were obtained form aerosol LP, from which, therefore, the fog catalyzing capability was the best. In conclusion, the oxidant of the fog aerosol greatly affects the catalyzing capabilities of nucleuses and the droplets growth processes, and consequently leads to the difference of photoelectric obscurities.
A new hollow nanoshell semiconductor was applied for generating smoke screen, and the dispersion and infrared jamming performance were researched. Firstly, the mircostructures and dispersion performance of the screen particles were analized by using SEM and cascade impactor; basing on the findings, the jamming performance of the screen to 8-12μm infrared light, 1.06 μm laser and 10.6 μm laser were examined, and the primary affecting factors and relationships got concluded. The results show that the dispersion performance is favorable as the diameters of more than 70% smoke particles are below 6.1μm; the smoke screen has better and satisfactory jamming performance to IR and laser as within 10 min, the decay rate maintains above 85% to 8-12μm IR and 90% to 1.06μm laser and10.6μm laser.
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