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1.
基于高吸水/保水材料的红外隐身技术研究   总被引:3,自引:0,他引:3  
介绍了基于高吸水/保水材料的红外隐身原理,对高吸水/保水材料的吸水/保水特性进行了研究,提出以高吸水/保水材料为基底的红外隐身复合材料的概念和模型设计,通过实验对其可行性和有效性进行了初步验证。结果表明,该复合材料能有效降低目标红外辐射特征,具有较好的红外隐身效果。  相似文献
2.
基于反常衍射的红细胞变形研究及蒙特卡罗仿真   总被引:3,自引:3,他引:0       下载免费PDF全文
杨静  郭永彩  高潮  郭孝恩 《光子学报》2005,34(4):542-546
用反常衍射理论分析了人体血液中静态红细胞和在剪切力作用下变形为椭球形红细胞的前向光散射特点,建立等体积/等表面积(V/S)光散射模型,采用蒙特卡罗法对稀悬浮液中静态和变形红细胞的光散射过程进行仿真,并计算出红细胞的变形度及三轴参数.结果表明,该理论下进行的细胞光散射分析精度与夫朗和费衍射理论相比可提高约一倍.  相似文献
3.
根据战场条件及红外材料的性能要求,在研究高吸水/保水材料特性的基础上对开发基于高吸水/保水材料的红外隐身复合材料的可行性进行研究分析,提出以高吸水/保水材料为基底的红外隐身复合材料的两种设计方案并制备出该红外隐身复合材料样板.通过对其进行红外效果评价,结果表明,该材料若作为军事目标的表面材料能有效改变目标的红外辐射特性,降低实验目标的可探测性.  相似文献
4.
超宽带时域天线阵列延时控制扫描实验   总被引:1,自引:1,他引:0       下载免费PDF全文
 超宽带(UWB)冲激雷达目标探测中时域天线阵列波束延时控制扫描是通过天线阵列单元间精确的延时控制实现的。在介绍UWB时域波束延时控制扫描原理的基础上,研制了用于UWB天线时域波束扫描的延时控制器,其延时步进为50 ps,延时精度可达10 ps。利用该延时控制器对单元间距42 cm的4单元UWB天线阵列H面方向进行了单元间延时控制波束扫描测量,扫描步进角度小于2°。结果显示,在0°,10°,20°和30°扫描时,实际扫描角度分别为-0.5°,10.5°,20°和29.5°,与理论计算值之间误差小于1°。  相似文献
5.
This paper presents a comparison study of numerical simulation of catalytic combustion of methane on Pt catalyst using two different physical models. The external surface model and the washcoat model were employed. The simulations were conducted in a two-dimensional monolith reactor with detail surface kinetics. The agreement of simulation results of the washcoat model with the measured data is good. However, in contrast to experimental data, the external surface method will produce a lower result of conversion of CH4 at low temperature due to the neglecting of the larger inner surface of the washcoat. Moreover, the effects of specific surface area and pore size of washcoat on reaction rate were discussed. It can be concluded that the washcoat model would provide a more realistic result and can enrich the contents of numerical simulation of catalytic reaction.  相似文献
6.
马宁  李晓毅  杨刚  陈谋 《应用光学》2015,36(1):155-160
 为了验证数字脉冲间隔调制(DPIM)在紫外光通信中应用的可行性,设计了基于FPGA的DPIM调制和解调系统。调制过程在锁存器的控制下,将串并转换后的数据输入比较器,并与计数值相比较产生DPIM调制信号;在解调端,利用计数器检测相邻光脉冲间的空时隙数,在锁存器的控制下,恢复得到原始数据。以16-DPIM为例,随机输入一组串行二进制数据,经过调制系统得到了16-DPIM信号;同样随机输入一个16-DPIM调制信号,通过解调系统恢复得到了原始数据。并在此基础上提出了一种新型的双幅度、定长DPIM调制方式,能更好地弥补DPIM符号长度不固定的缺陷。  相似文献
7.
分析了启闭键控调制(OOK)、脉冲位置调制(PPM)、差分脉冲位置调制(DPPM)和数字脉冲间隔调制(DPIM)的编码结构,然后从带宽需求、平均发射功率、传输容量和差错性能等方面对各种调制方式进行了仿真对比。结果表明,DPIM调制比PPM具有更高的传输容量和更少的带宽需求,并且解调对同步要求较低,实现更简易,并结合紫外LED阵列将作为今后实用化紫外光源的发展趋势,DPIM调制在未来紫外光通信系统的应用中将具有更大的优势。  相似文献
8.
The fill factor of dye-sensitized solar cells based on the ZnO nanowire array is very low, which is usually ascribed to a rapid charge recombination. In this article, the influence on the fill factor of ZnO nanowire array cell is investigated and discussed by comparing dark current and decay rate of open circuit potential of the ZnO nanowire array cell with those of the ZnO nanoparticle cell, TiO2 nanoparticle cell and TiO2-coated ZnO nanowire array cell. The results demonstrate that the low fill factor of the ZnO nanowire array cell is largely caused by a rapid decrease of electron injection efficiency rather than a rapid charge recombination, which is decided by the absorption nature of Ru-complexed dye molecules on ZnO surface and repellency of radial electric field. The fill factor of the ZnO nanowire array cell can be improved by coating ZnO nanowires with a wide band gap semiconductor material or metal oxide insulator.  相似文献
9.
侯倩  李晓毅  何刚  李子  赵芳  肖文林 《光学技术》2011,37(6):699-703
利用蒙特卡罗方法对紫外光非视距传输过程进行了模拟,讨论了传输过程中固体角的确定,仿真分析了系统的角度设置对传输损耗的影响。结果表明,增大收发仰角可以降低系统的传输损耗,并且小角度集中发射与大视场角接收可以降低系统的传输损耗。  相似文献
10.
Aim at the underdetermined convolutive mixture model, a blind speech source separation method based on nonlinear time-frequency masking was proposed, where the approximate W-disjoint orthogonality (W-DO) property among independent speech signals in time-frequency domain is utilized. In this method, the observation mixture signal from multimicrophones is normalized to be independent of frequency in the time-frequency domain at first, then the dynamic clustering algorithm is adopted to obtain the active source information in each time-frequency slot, a nonlinear function via deflection angle from the cluster center is selected for time-frequency masking, finally the blind separation of mixture speech signals can be achieved by inverse STFT (short-time Fourier transformation). This method can not only solve the problem of frequency permutation which may be met in most classic frequency-domain blind separation techniques, but also suppress the spatial direction diffusion of the separation matrix. The simulation results demonstrate that the proposed separation method is better than the typical BLUES method, the signal-noise-ratio gain (SNRG) increases 1.58 dB averagely.  相似文献
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