Choice of a pertinent color space for color texture characterization using parametric spectral analysis

This article presents a comparison of different color spaces including RGB, IHLS and L?a*b* for color texture characterization. This comparison is based on the fusion of the independent spatial structure and color feature cues. In IHLS and L*a*b*, two channel complex color images are created from the luminance and the chrominance values. For such images, two dimensional complex multichannel linear prediction models are used to perform parametric power spectrum estimation and the structure feature cues are computed from this estimated power spectrum. Quantitative comparison of auto spectra of luminance and combined chrominance channels for different color spaces is done. This comparison is based on the degree of decorrelation between luminance and chrominance information provided by different color space transformations. Three dimensional histograms are used as color feature cues. Then, to classify color textures, Kullback-Leibler divergence based symmetric distance measures are calculated for pure color, luminance structure and chrominance structure feature cues. Individual as well as combined effect of information from all feature cues on classification results is then compared for different color spaces and different color texture data sets. The proposed color texture classification method performs better than the state of the art methods in certain cases. The L*a*b* color space gives us a better characterization of the chrominance spatial structure as well as the overall spatial structure for all of the chosen data sets. Experimental results on pixel classification of color textures are also presented and discussed.     

High frequency complex permeability of flake-shaped Fe_(74)Cr_2Mo_2Sn_2P_(10)Si_4B_4C_2 particle composite material

A composite consisting of flake-shaped Fe74Cr2Mo2Sn2P10Si4B4C2 particles was prepared.The flake-shaped particles included in the composite were prepared by planetary ball milling.The complex permeability of the composite material was measured at frequency range from 10 MHz to 8.5 GHz.The permeability of the composite containing flake-shaped particles was much higher than that of the spherical particles.The permeability of particles was improved by means of heat-treatment.In contrast to the random-spatial-di...     

Molecular recognition of DNA–protein complexes: A straightforward method combining scanning force and fluorescence microscopy

Combining scanning force and fluorescent microscopy allows simultaneous identification of labeled biomolecules and analysis of their nanometer level architectural arrangement. Fluorescent polystyrene nano-spheres were used as reliable objects for alignment of optical and topographic images. This allowed the precise localization of different fluorescence particles within complex molecular assemblies whose structure was mapped in nanometer detail topography. Our experiments reveal the versatility of this method for analysis of proteins and protein–DNA complexes.     

夹芯复合墙板在水平荷载作用下变形的有限元分析

利用有限元程序对夹芯复合墙板在水平荷载作用下的变形进行分析,探讨墙板结构层厚度、水平桁架、纵向桁架、钢筋网作为主要参数变化时对墙板变形的影响。分析得出:影响墙板刚度的主要因素是结构层厚度,其次是水平桁架,其他因素影响较小。该结论为新型复合墙板的研发提供了理论依据。     

纳米改性变压器油-纸复合绝缘频率响应特性

为寻求提高变压器油纸复合绝缘特性可能途径,开展了纳米改性变压器油-纸复合绝缘频率响应特性研究。利用电介质频率响应法,对比测试了添加纳米改性前后油纸复合绝缘不同微水含量、在不同温度条件下,10^-4～10^-6Hz范围频率响应;建立基于Cole-Cole函数的弛豫模型分析实验结果,并通过最小二乘法拟合得到弛豫模型参数;分析小同微水含量及温度条件下添加纳米粒子对弛豫参数的影响。结果表明：所建立的弛豫模型能较好地反映油纸复合绝缘频率响应特性,弛豫模型参数能反映油纸复合绝缘状态的变化规律;添加纳米粒子引入了新弛豫机制,在低频及高频段,降低了油纸复合绝缘的介质损耗,在0．1～100Hz频率范围内却增大了其介质损耗,且随着温度升高及微水含量增加,影响越显著。     

基于80296和CPLD的补偿电网微机选线装置的设计

分析了补偿电网单相接地故障时故障线路与非故障线路零序电流的分布特性,将补偿电流融入到选线的计算和判断中,提出了一种新的接地选线方法———电流融合法,该方法具有计算简单、保护裕度大选线准确快速的特点,并在此基础上设计了以INTEL80296和CPLD为主控单元的微机选线装置,该装置对装设了预调式消弧线圈的补偿电网的选线具有很高的准确性。     

FAFFA加速的PO-MM研究复杂金属载体上线天线电磁特性

本文提出了一种快速远场近似(FAFFA)加速的混合物理光学矩量法(POMM),利用FAFFA加速计算矩阵方程中的矩阵矢量积,明显提高了计算效率.对物体表面上的远场组之间的耦合作用推导出了一组简洁的计算公式,并分析了计算复杂度.复杂金属组合体上线天线输入导纳、互导纳和方向性图的计算结果与文献结果一致.利用该方法分析计算了一个舰船模型上线天线的电磁特性.数值结果表明了这种方法的正确性和工程应用中的有效性.     

Measurement Method of the Thickness Uniformity for Polymer Films

Several methods for investigating the thickness uniformity of polymer thin films are presented as well their measurement principles.A comparison of these experimental methods is given.The cylindrical lightwave feflection method is found to can obtain the thickness distribution along a certain direction.It is simple and suitable method to evaluate the film thickness uniformity.     

(Zn_(1/3)Nb_(2/3))~(4+)取代的BNT系无铅压电陶瓷性能

采用两步合成工艺,制备了新型Bi1/2Na1/2Ti1–x(Zn1/3Nb2/3)xO3(简称BNTZN—100x)系无铅压电陶瓷。研究了B位复合离子(Zn1/3Nb2/3)4+取代量对BNT陶瓷介电及压电性能的影响。结果表明:当0.005≤x≤0.020时,该体系陶瓷具有三方、四方共存的准同型相界(MPB)结构。在MPB附近,具有较佳的压电性能:当x为0.020时,d33为97pC/N,kt为0.47。εr-t曲线显示该体系材料具有明显的弥散相变特征。具有高kt值,低kp值;kt/kp较大,具有较大的各向异性,是一种适合高频下使用的优良超声换能材料。     

On Solving TM0n Modal Excitation in a Ka-Band Overmoded Circular Waveguide by the Conservation of Complex Power Technique

To measure the radiation properties of relativistic diffraction generator (RDG) in Ka-band, a TM0n modal excitation model is established, which consists of an overmoded circular waveguide and a coaxial line feeding probe. Using the transverse E-field mode matching and the conservation of complex power technique (CCPT), we deduce the scattering matrix at coaxial line to coaxial line and coaxial line to circular waveguide junctions. Then using the overall cascaded junction scattering matrix, the numerical results for the reflection coefficient of the coaxial line and the power distribution of TM0n multi-modal are presented. The numerical results are in agreement with HFSS simulation results and experimental results. The analysis shows that by choosing the appropriate position of coaxial line probe, the power proportion of the device operating mode excited in circular waveguide could be the largest.