KEYWORDS: Infrared radiation, Solar radiation models, Solar radiation, Radiation effects, Temperature distribution, Atmospheric modeling, Air temperature, Thermal modeling, Emissivity, Surface air temperature
Military vehicles are vulnerable to hostile infrared reconnaissance in the battlefield. So, it is essential to investigate the infrared radiation characteristics and camouflage methods of the vehicle. This paper proposes a method utilizing heat exchange theory to study the temperature distribution and the infrared radiation characteristics of a simplified vehicle prototype. The research reveals that the temperature distribution and the infrared radiation distribution are different for all six surfaces, which are mainly influenced by internal heat source, air temperature and solar radiation. This study is expected to provide useful guidance to vehicle camouflage pattern design.
The transmission of high-power microwave (HPM) with a frequency of 1 GHz in a plasma double-line induced by intense femtosecond laser pulses is discussed by CST software. The simulation results indicate that the EM wave can propagate around the plasma double-line rather than in the over-dense plasma with a velocity near the speed of light. It can also be obtained that the time evolution of the electric field is consistent with the duration of the incident HPM. We also discover that the electric field increases monotonically with increasing the line radius. Meanwhile, the electric field is inversely proportional to the propagation distance along the plasma double-line and the spacing between two lines. Furthermore, the attenuation value of the EM wave in the plasma transmission line can be calculated at approximately 0.03 dB/m in a double-line with an effective plasma electron density of 1016 cm–3 .
Based on one-dimensional photonic crystals (1D PCs), we studied an innovative multispectral compatible stealth material for visible light, infrared, and 1.06-μm laser. The fabricated PCs had advantages of different colors, low emissivity in the atmospheric windows, and low reflectance at 1.06-μm waveband. According to some relevant experiments, the prepared films possessed colors of yellow, green, and blue, which could be used to simulate the color of the desert, woodland, and ocean, respectively. The infrared stealth performance of films showed that the thermal radiation in the atmospheric windows of 3 to 5 μm and 8 to 14 μm could be reduced effectively. In addition, the films’ reflectance spectra measured by spectrometer indicate that the reflectance at 1.06 μm is below 20%, which, in practice, could enormously reduce the echo power of incident lasers.
KEYWORDS: Solar cells, Infrared radiation, Solar radiation, Solar radiation models, Sun, Solar energy, Temperature metrology, Atmospheric modeling, Thermal modeling
The infrared characteristics of the target is very important for target recognition. The infrared radiation characteristics are different between damaged solar panel and normal working solar panel. It is the characteristic position for the solar panels’ nondestructive fault testing. In this paper, the temperature model of solar panels is established, and the numerical calculation is carried out. The calculated results and the measured data matching well verify the correctness of the calculation model. The results also show that the temperature of solar panels which are damaged are higher than the temperature of those who are normal working. On the basis of the temperature calculation, the infrared radiation characteristics of solar panels are calculated .The result shows also that the infrared radiation intensity of those damaged solar panels are higher than the normal working solar panels. This provides the theoretical support for the infrared nondestructive testing of solar panels.
Genetic algorithm (GA) is a commonly used algorithm in optical network routing and wavelength assignment (RWA). In order to adapt to the development trend of next-generation software-defined optical network (SDON) with higher speed, wideband, long distance and large capacity, this paper proposes a dynamic, improved GA-based RWA algorithm which reduces the complexity of the algorithm and improves the performance of the algorithm. The simulation results show that the algorithm can effectively reduce the blocking rate and improve resources utilization rate in SDON compared with the classical algorithm and GA.
In order to verify the heat dissipation characteristics of selective low emissivity materials, the traditional low emissivity materials and selective low emissivity materials were coated on the oxidized steel surface, and the heat transfer model between the target and the dark room was established. Finally, the heat dissipation characteristics of selective low emissivity materials were simulated, and the effects of the emissivity and the darkroom temperature on the heat dissipation characteristics of selective low emissivity materials were analyzed. The results showed that for high temperature targets, selective low emissivity materials had better heat dissipation characteristics than traditional low emissivity materials. The lower the emissivity in mid-far infrared bands, the better the heat dissipation characteristics of selective low emissivity materials. When the ambient temperature of the dark room fell from 30°C to -30°C, the lower the temperature, the better heat dissipation characteristics of selective low emissivity materials.
As a kind of special electromagnetic medium, femtosecond laser plasma has the potential of transmitting the electromagnetic wave. In this paper, a theoretical study on 6 GHz EM wave guiding performance of the plasma filament is carried out with the software XFDTD. Then, an experimental setup for the interaction between the EM wave and the plasma filaments is established. Based on the data measured by oscilloscope, the transmission properties of the EM wave along the filament are obtained. The results show the electric field is enhanced out of the waveguide with the plasma filament. The guiding performance of the plasma filament on the TE polarization wave is better than that on the TM one, which is consistent with the experimental results. For TE polarization wave, the plasma filament can reduce the transmission pulse energy greatly and the attenuation is up to 3.5 dB in the experiment. The research results show that the laser plasma filament can provide efficient transmission of the EM wave energy.
In order to study the effect of adding hexamethylenetetramine (C6H12N4) on the infrared radiation properties of a mixture decoy of Pb3O4/PTFE/Mg, a formula of Pb3O4/PTFE /Mg = 10: 3: 7 was taken as a basic formula, and different content of C6H12N4 was added in the basic formula to design seven different pharmaceutical formulations. The Combustion process of samples was recorded using a 3-5 micron mid-infrared thermal imager, and the burning time, mass burning rate, radiation area, radiance, as well as the radiation intensity of each sample were calculated. The experimental results show that with the continuous addition of C6H12N4, the combustion temperature of the samples increased firstly and then decreased, besides, the combustion time became longer while the mass burning rate became smaller, when the proportion of additives reached 6%, the temperature came to its maximum of 916.76°C and the radiant brightness was increased from 10956.50 W/m2/Sr to 13517 W/m2/Sr. The longest combustion time was 9.32s with the lowest mass burning rate of 1.72g/s when the proportion of additives reached 15%. And the radiation intensity was increased from 1079.05W/Sr to 1254.1W/Sr when the proportion of additives reached 9%. This showed that the appropriate addition of 6% to 9% of C6H12N4 in the basic formulation contributes to the improvement of the combustion performance and radiation performance of the Pb3O4/Mg/PTFE decoy.
Strong electromagnetic pulse (EMP) may lead to serious damage once it is coupled into the interior of the electronic system. As a kind of special electromagnetic medium, plasma has the ability of shielding strong EMP. Therefore, EMP protection technology based on the plasma is of pratical significance. The experimental setup of the interaction between the nuclear electromagnetic pulse (NEMP) and the plasma based on a one-layer cylindrical plasma array is built. Combined with the density distribution characteristics, the protection performance of the plasma array against the NEMP is studied. The results indicate that the protection performance of the plasma array against the TE polarization NEMP is better than that against the TM one. For both TE and TM polarization NEMP, the one-layer cylindrical plasma array can reduce the transmission pulse energy greatly and the energy attenuation is up to 10dB when the electron density is 8.5×1016 m-3.
In order to study the effect of the ratio of oxidizing agent to reducing agent on the performance of the trilead tetraoxide/ Teflon/magnesium (Pb3O4/PTFE/Mg) powder decoy compounding agent, 5 different pharmaceutical formulations are designed by maintaining constant oxidant formula and changing the ratio of oxidant agent and reducing agent. Then the mixed powder is pressed into a powder by a table press. The combustion process of the drug column was measured with an 8-14 micron infrared thermal imager, and the burning time, mass burning rate, radiation area, radiance, and radiation intensity of each sample were calculated. The results show that with the increase of the proportion of reducing agent, the burninging time of the sample becomes shorter and the mass burninging rate becomes larger. The maximum temperature of the flame increased with the proportion of reducing agent first and then decreased. When the ratio of oxidant agent to reducing agent is 1.5:1, the maximum temperature of sample combustion reaches a maximum of 1503°C. The radiance increases first and then decreases with increasing proportion of reducing agent, and When the ratio of oxidant agent to reducing agent is 1:1.5, the infrared radiance is the maximum, which is 2510 W·m-2·Sr-1.Radiation intensity increases as the proportion of reducing agent increases. It can be seen that in the 8-14 micron band, when the ratio of oxidant agent to reducing agent is 1:1.5, the radiation characteristics of the sample is best and the sample is the best one as infrared decoy.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.