Papers by Keyword: Infrared Radiation

Abstract: The factors influencing the screening of thermal radiation by environmentally friendly aerosols have been theoretically substantiated and experimentally determined. The processes of absorption and scattering of thermal radiation have been analyzed.

Abstract: The paper proposes the analysis of an alternative technology for manufacturing deodorant roll-on balls of polypropylene. With the current extrusion-blowing technology, the manufacturing of these balls results in an uneven wall thicknesses and a large technological runner of material that needs to be grinded and reintroduced into the injection equipment, which involves additional raw material and energy consumption.The proposed alternate method of manufacturing these balls (as spherical objects) is to form the ball from two ball halves joined together by infrared radiation welding. This process will result in significant savings in raw materials and energy.Further improvements of dimensional capabilities and control of welding parameters are required prior the transfer on high productivity manufacturing lines. Additionally, this technology can be assimilated into other applications where hollow balls of plastic are used.

Abstract: The operating range of ground-based detector on hypersonic vehicle in rarefied atmosphere space is researched. Both the imaging dispersion and the difference of radiation intensity between object and background are considered, and a new model of operating range is proposed. By experiments, the dispersion coefficient changes with the distance between object and detector and has great effect on operating range; meanwhile, the higher the velocity of vehicle is, the further the operating range is. And the detector working at medium wave infrared has larger operating range. Compared with existing method, the proposed algorithm achieves better result in the field experiment.

Abstract: A spatial cold-shield system with cryogenic phase change refrigeration was studied to decrease the surface temperature of spacecraft under 100 K and surface infrared intensity under 0.5 W/m² within 30 minutes in space. A 3-D unit and systematic model were established to simulate the real structures and the variation regularities of the major parameters under different flying periods. A simplified unit model and a systematic model were established to simulate the heat-transfer and flow-field of cold shield in cryogenic, vacuum and micro-gravitational conditions. The unit and systematic experiments were carried out to study the cryogenic phase change refrigeration in cold shield on the ground. The results indicated the simulated and experimented parameters of cold-shield were consistent with the designing conditions of spacecraft. The systematic model could make the LN₂ touching the surface easily and causing the surface temperature distributed more uniformly. The cold-shield could meet the requirement of cryogenic infrared intensity by phase change refrigeration in space.

Abstract: Using C51 SCM, a set of simple infrared communication system has been designed through combining with the infrared devices, and infrared wireless communication has been implemented in short distance within the function. It is different with the general infrared remote controller that doesn’t use coding and decoding chip to realize the coding and decoding of the sending and receiving, but through the SCM encoding and decoding procedures to achieve the sending and receiving of infrared signal, so as to realize the communication function of infrared remote control.

Abstract: Textile materials almost belong to high polymer material,which have three kinds of phenomena below: reflection, projection and absorption. Due to the particularity of fiber structure, radiation incident to the fiber radiation occurs the multiple internal reflection as well as the transmission and absorption of part of radiation.

Abstract: Tourmaline is a kind of non-metal mineral, which has been applied widely in environmental protection, such as radiating infrared, producing ion negative and shielding electromagnetic radiation. It is proved that tourmaline has the properties of spontaneous electrode effect and weak magnetism. Tourmaline from different areas has some differences on internal crystal structure and chemical composition. This paper studied on the infrared radiation properties of four different kinds of tourmaline produced in Hebei Guangxi, Henan, Xinjiang. Our experiments indicated that different species of tourmaline has different rate of infrared radiation on the same condition, and infrared radiation rate changes with temperature and particle size.

Abstract: In this paper, the effect of MnO₂ addition the infrared emissivity on ZrO₂-Al₂O₃-SiO₂ low thermal conductivity materials was investigated. The phase and microscopic morphology of the samples with the heat treatment at different temperatures were characterized by XRD and SEM. The results show that the infrared emissivity of ZrO₂-Al₂O₃-SiO₂ materials increased nearly 7% to 0.911 by adding 10 wt% MnO₂. After heat treatment at different temperature, the main phase of ZrO₂-Al₂O₃-SiO₂ materials were t-ZrO₂ and mullite, ZrO₂-Al₂O₃-SiO₂ materials with MnO₂ addition were molten and the phase composition was t-ZrO₂, Al₂O₃, and m-ZrO₂.

Abstract: The aerodynamic heating and infrared radiation characteristics of BrahMos supersonic cruise missile were investigated. The aerodynamic heating was simulated using finite volume method, and the infrared radiation characteristics were simulated by reverse Monte Carlo method. Infrared radiation characteristics of missile surface were analyzed in different surface emissivity and flight altitudes, and the effects of environmental radiation and atmospheric attenuation were considered. The results show 8~14μm and 3~5μm environment radiation were approximately 10% and 2.4% of total radiation respectively, when the surface emissivity is 0.3. The proportion of environmental radiation reduces nearly half when the surface emissivity increases by 0.2.

Abstract: Considering the limitation of maneuverability and real-time performance of the common atmosphere transmission calculation software, a simulation system of atmospheric transmission attenuation effect for mid-wave infrared radiation is designed in this paper. Firstly, the atmospheric transmission attenuation effect for mid-wave infrared radiation is studied. Then an approximate model for atmospheric transmission attenuation effect for MWIR is established based on theoretical approaches and empirical formula. The process of simulation system of atmospheric transmission attenuation effect for MWIR is designed, and corresponding simulation system is implemented. Finally, the comparative experiments with MODTRAN are carried out to validate the performance of the simulation system, and experimental results show that it gives a very good agreement between the calculated results within an attitude of 3 km. In addition, this system has higher performance in real-time compared with Modtran.