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31.
本文提出了能同时抑制加性噪声,脉冲噪声干扰和点扩展函数模糊,又能保护图象边缘及细节信息的新型滤波方法—“二维Kalman-Median混合自适应滤波”,并成功地应用于统计图象恢复,取得了满意的效果。  相似文献   
32.
A dose of SBR modifier added to asphalt can improve asphalt's performance in stability, permanence, viscosity, and resistance to aging. Better application performances of asphalt pavement are affected directly by proper SBR modifying. This paper shows some investigations that confirm the relationship between the addition of SBR with the structure and the properties of SBR-modified asphalt. This paper also discusses the modified asphalt high temperature property, low temperature ductility, and mechanism of SBR-modified asphalt. The addition of SBR modifier showed an increase in viscosity, softening point, and elastic recovery of modified asphalt with rising temperature. When the temperature rises, the improvement of SBR-modified asphalt in softening point, elastic recovery, and visco-toughness result from SBR cross-linking. Although the lengths of low temperature ductility of SBR-modified asphalt are increased, the viscosities of modified asphalt increase; however, the softening point between the upper layer and lower layer were about 1.8°C after the isolated experiment.  相似文献   
33.
Instead of carbon, Mo2C is used to modify the MoO2 material for the first time. The presence of highly conductive and electrochemical inactive Mo2C decreases the resistance of the charge transport and enhances the structural stability of MoO2 nanoparticles upon lithiation and delithiation, ensuring the superior cycling stability and high rate capability of the heteronanotubes. Cycled at 200 and 1000 mA g?1 for 140 cycles, the discharge capacities of the MoO2/Mo2C heteronanotubes remain to be 790 and 510 mAh g?1, respectively. This work demonstrates the potential of the novel heteronanotubes for application as an electrode material for high‐performance Li‐ion batteries.  相似文献   
34.
Bioinspired surfaces with special wettability have attracted a significant attention in recent years because of their potential applications for no loss liquid transfer, anti‐icing, and self‐cleaning. Herein, the realization of two extreme superhydrophobic states on 1H, 1H, 2H, 2H–perfluorooctyltriethoxysilane‐modified TiO2 nanotube arrays (NTAs) is described by changing the structural characteristics of nanotubes while keeping the surface chemical composition constant. The water adhesive force is regulated in a wide range from ≈4.4 to ≈89.6 μN by the nanotubular diameter, length, density, and surface roughness. The cooperation effect between the negative pressures induced by the volume change of sealed air‐pockets and the van der Waals' attraction at solid–liquid interface contributes to the water adhesion. The superhydrophobic TiO2 NTAs with a high adhesive force is used as a “mechanical hand” to transfer water microdroplets without any loss, and the one with extremely low adhesive force is utilized as a self‐cleaning and anti‐icing surface.  相似文献   
35.
ZnGa2O4 and ZnGa2O4: Mn2+/Eu3+ with uniform nanosphere (diameter about 400 nm) morphology have been synthesized via a facile hydrothermal approach. XRD, Raman spectra, XPS, FT‐IR, SEM, TEM, photoluminescence (PL), and cathodoluminescecne (CL) spectra are used to characterize the resulting samples. The controlled experiments indicate the dosage of trisodium citrate and pH values are responsible for shape determination of the ZnGa2O4 products. The possible fast crystallization–dissolution–recrystallization formation mechanism for these nanospheres is presented. Under UV light and low‐voltage electron beam excitation, ZnGa2O4, ZnGa2O4: Mn2+ and ZnGa2O4: Eu3+ emit bright blue, green, and red luminescence, respectively. Based on density functional theory calculations from first principles, the green and red emission are caused by the Mn 3d and Eu 4f electronic structures, respectively. Besides, the dependence of the CL intensity on the calcination temperature and electrical conductivity of the samples is presented. The ZnGa2O4: Mn2+ nanospheres have a higher CL intensity than that of bulk samples under the same excitation condition. The realization of three primary colors from a single host material suggests that full color display based on ZnGa2O4 nanospheres might be achievable, showing that these materials have potential applications in lighting and display fields.  相似文献   
36.
本文给出了厚透镜实现分数阶付里变换的光学结构;定量分析了阊最透镜和双厚秀镜结构中分数付里叶变换和透镜参数之间的关系。计算表明用厚透镜可以实现分类阶付时变换。  相似文献   
37.
A new type of photovoltaic system with higher generation power density has been studied in detail. The feature of the system is a V-shaped module (VSM) with two tilted monocrystalline solar cells. Compared to solar cells in a flat orientation, the VSM enhances external quantum efficiency and leads to an increase of 31% in power conversion efficiency. Due to the VSM technique, short-circuit current density was raised from 24.94 to 33.7 mA/cm2, but both fill factor and open-circuit voltage were approximately unchanged. For the VSM similar results (about 30% increase) were obtained for solar cells fabricated by using mono-crystalline silicon wafers with only conventional background impurities.  相似文献   
38.
目前,多级维纳滤波器是一种收敛速度最快的降秩空时自适应处理算法,但它只适合于处理平稳随机信号,不能直接用于抑制非均匀的机载共形阵雷达杂波。该文在分析共形阵雷达杂波特性的基础上,提出采用俯仰向空域滤波改善杂波的非均匀性,改进了传统的协方差矩阵加权算法,最后形成了一种基于俯仰向空域滤波的协方差矩阵加权多级维纳滤波算法,用于抑制共形阵雷达杂波。仿真结果表明,该文方法抑制共形阵雷达杂波的综合性能优于现有其他方法,且计算复杂度低,收敛速度快,便于工程实现,在共形阵雷达杂波抑制中具有实际应用前景。  相似文献   
39.
量子级联红外探测器   总被引:2,自引:0,他引:2  
半导体基中远红外探测器在成像、传感、国家安全以及国防领域具有广泛的应用背景.目前,在这个领域最主流的技术之一是量子阱红外探测器( QWIPs).传统的量子阱红外探测器往往存在较大的暗电流和较低的工作温度等限制.量子级联探测器( QCDs)是一种新型的光伏型量子阱红外探测器.其工作原理基于电子吸收光子后在量子阱的子带间跃...  相似文献   
40.
我国科普的新发展和需要深化研究的重要课题   总被引:4,自引:2,他引:4  
比较系统地概括和梳理了我国近年来科技传播与普及(科普)的最新发展情况,分析并总结了我国科普工作在科普理念、科普政策、科普实践、公民科学素质建设、科普理论、学科建设等方面取得的新成就,并对我国未来科普工作和科普研究的发展趋势进行了预测,提出了需要深化研究的重要课题。文章认为,我国近些年来在科普研究和实践领域都取得了一系列重要的突破,科普工作已经迈入一个全新的发展阶段,科普研究也获得了一系列重要的成果并将更好地发展。  相似文献   
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