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51.
高分子材料辐射接枝苯乙烯的研究进展   总被引:6,自引:0,他引:6  
对各高分子材料辐射接枝苯乙烯的动力学,接枝方法及接枝材料的应用进行了综述,讨论限辐射剂量,剂量率,温度,后效应,溶剂,添加剂和高分子材料厚度及结晶性等方面对接枝反应的影响。  相似文献   
52.
无源微波遥感用于地震预报的实验研究   总被引:4,自引:1,他引:3  
对无源微波遥感用于地震预报在理论研究的基础上对不同岩性不同结构的岩石试件进行了加载实验,测量了岩石试件的微波辐射随载荷的变化.实验得出:岩石试件的微波辐射能量随岩石应力状态变化而显著变化;而且,不同的波段变化的幅度不同;同一波段不同极化方式的波随应力变化的变化量也不同;微波辐射能量的变化能够被卫星微波遥感探测器探测到.实验还发现,岩石试件临破裂前出现明显的微波辐射异常.  相似文献   
53.
One promising method of locating buried objects, such as land mines, is to use optical systems for detecting contrasts in surface temperature. With enhanced knowledge about the interacting physical processes behind these temperature contrasts, it is possible to improve detection precision. In such a context, moisture movement in the soil and moisture evaporation from the surface have been found to be of particular interest. This study was based on indoor experiments on wet and dry sand exposed to radiation from a solar panel. Simulations of heat and moisture transfer conducted with a one-dimensional model are also presented for the experiments. The calculations were successful in accurately predicting surface temperatures for both wet and dry sand, making it possible to predict surface temperatures under different conditions. These findings will contribute to increasing the probability of successful detection of buried objects under real conditions using optical methods.  相似文献   
54.
Electric dipoles radiate an electromagnetic field into their surroundings. The electric and magnetic fields from a point source or from linear dipoles have components parallel to a spherical surface but also a radial component. In most investigations on radiated fields, only the part of the electric field that is parallel to a spherical surface is taken into account. The argument is that only that component contributes to the radiated energy. Here we show that the phase front in the lower half space is not a spherical surface and hence, the radial components contribute to radiated energy. We show differences in radiation patterns for point electric dipoles and linear dipoles, either modeled as perfectly conducting wires or as resistively loaded wires. Our primary interest lies with improving image resolution through processing of Ground-Penetrating Radar data. Here the emphasis lies with understanding the radiation characteristics of linear dipoles that can be incorporated with image processing algorithms. The model uses a thin-wire approximation for the transmitter antenna. The solution to the discrete system of equations is solved, incorporating interaction between the interface, using a CGFFT scheme including symmetrization and a newly developed preconditioning operator. We look at the electric and magnetic fields as well as the time-averaged Poynting vector radiation patterns in the E-plane and H-plane of the transmitting antenna. The results show that the radial component of the radiated electric and magnetic field is not negligible, even at distances more than seven wavelengths away from the antennas.  相似文献   
55.
提出了一种基于修正的M距离辐射源识别新方法。通过计算机仿真 ,验证了该方法的合理性与有效性  相似文献   
56.
地基辐射阻尼和库水对拱坝非线性地震响应的影响   总被引:2,自引:0,他引:2  
针对拱坝坝体—地基—水库系统的动力计算分析,采用考虑无限地基辐射阻尼、坝体横缝非线性和自由场输入的模型程序,以溪洛渡拱坝为工程实例,对不同库水位下,考虑或不考虑地基辐射阻尼的工况进行了系列的计算对比研究。研究结果显示,低水位是横缝开度控制工况,高水位是坝体应力控制工况;对所有水位,地基辐射阻尼都带来坝体地震响应的全面降低,但不影响反应的总体规律。  相似文献   
57.
Q-switch for pulsing laser beam and Galvano scanner for rapid scanning laser beam were adapted to manipulatemicro solid particles in a water droplet.The trapping of fine particles at micron-sized diameters by a YAG lasersystem,induced flows,and the induced motion of the particles by laser beam irradiations are discussed.Particlerotations are observed by using anisotropic micro objects,and moreover the rotational rate with clockwise direc-tion is 22 r/min.The fragments of a cover glass were mixed in a water droplet,and their size and shape are un-even.The rotation of that non-spheres without scanning by the Galvano scanner is also observed in water.  相似文献   
58.
王纳秀  朱毅  朱卫华  傅远  夏绍建 《核技术》2006,29(5):326-328
报道了同步辐射装置光束线关键部件之一的晶体单色器晶体热应变的ANSYS有限元模拟结果,并与实验结果进行了比对,模拟结果在实验误差范围(约士15%)内与实验数据符合,证明了模拟结果的可靠性.  相似文献   
59.
Suitability of sweet sorghum in Greece, where irrigation supply during crop development is limited as rainfall is scarce and evapotranspiration loss is high, is examined in relation with radiation availability. A two-year field experiment was conducted, in central Greece, imposing four soil water regimes via different irrigation treatments: (1) Highly irrigated, (2) Highly irrigated till anthesis when irrigation stopped, (3) Medium irrigated, and (4) Low irrigated. It was found that above-ground dry biomass production from non-water-stressed sweet sorghum plants suggests a high productivity potential among C4 crops. Under water shortage, radiation use efficiency may be significantly lower. Radiation use efficiency seems to be linearly related to water consumption. Stressed plants (probably except severely stressed) seem to use available water more efficiently than unstressed plants. The slope of the line relating dry matter produced and water evapotranspired increases the sooner the stress is sensed. Yield reduction resulting from post-anthesis irrigation stopage is very little. High water use efficiency values tend to be related with low radiation use efficiency values.  相似文献   
60.
The effects of thermal radiation on the pseudosteady state and transient behavior of porous char particles exposed to an oxygen containing environment are investigated. The numerical simulation results show that particles that do not interchange radiant energy with their environment are characterized by wider ambient temperature regions where multiple steady states exist, higher combustion rates, and lower burning times  相似文献   
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