一维矩形刻槽相位栅的减反特性与结构优化

 为了得到一种结构简单、便于制作的可应用于可见光波段的减反射膜,利用等效介质理论研究了表面具有矩形刻槽周期分布形式的介质膜的减反射特性,比较了4种不同基底材料的减反特性,选用聚甲基丙烯酸甲酯（PMMA）作为基底分析了一维单层矩形光栅结构的减反射膜的占空比、蚀刻深度、入射波长和入射角度对减反射特性的影响;给出了可见光波段的减反射膜的结构设计参数。研究结果表明：当入射角小于30°时,可见光中的短波段（0.4 μm～0.55 μm）反射率低于2%;当入射角小于10°时,该减反射膜可以使0.4 μm～0.8 μm可见光的反射率低于2%。     

Surface topography effects on glow discharge depth profiling analysis

Glow discharge optical emission spectroscopy (GD‐OES) has been shown to be of immense value in elemental depth profiling of thin or thick films on conductive or non‐conductive substrates. For aluminium, GD‐OES has been employed to examine locations of markers and tracers in anodic films, thereby assisting understanding of transport phenomena. In order to investigate the influence of surface topography on depth profiling analysis, anodic aluminium oxide films of various thicknesses, with incorporated electrolyte species, were produced on superpure aluminium substrates of controlled roughnesses. The distributions of incorporated species in the films were subsequently probed. Surface topography modifications and consequent depth resolution degradation were examined during depth profiling analysis performed by GD‐OES. The results reveal that the sputtering process leads to the roughening or smoothing of the surface topography of the specimen for a ratio of the film thickness to the amplitude of the substrate texture less, or greater, than 1 respectively. As a consequence of the surface topography dependence of the ion bombardment, analysis of thin films over rough surfaces suffers from depth resolution limitations due to sputtering‐induced topography changes, thereby limiting quantification of the resultant spectra. Copyright © 2010 John Wiley & Sons, Ltd.     

关于YBCO/MgO超导薄膜电阻转变和微波性质的研究

利用标准的四引线方法研究了磁场平行和垂直于YBCO/MgO超导薄膜表面时的电阻转变.另外,本文采用微带谐振技术研究了该超导薄膜的微波性质.我们获得了该超导薄膜在绝对零度时的穿透深度λ0=280 nm,并且计算出了该超导薄膜的表面电阻,结果显示在60 K,7.78 GHz时Rs=78.2μΩ;在76 K,7.77 GHz时Rs=179.8 μΩ.     

辐射超声速扩散传输产生条件的研究

 利用1维辐射扩散方程的解析理论,在外加辐射源为恒温源的条件下,对能够产生辐射超声速扩散传输的条件进行了研究,可以解析地得出在固定物质密度下能够产生超声速扩散流的参数区域。分析得出：对于一个固定的恒温外源,随着时间的增加,热波波头位置是随时间的平方根增长的,光学厚度正比于波头位置,也是随时间而逐渐增加的;而马赫数是按时间平方根倒数减少的。并推导出在不同密度下恰好产生超声速扩散时,辐射源温度和辐射热波波头位置满足的临界值条件,它们是关于介质密度的函数关系式。最后以SiO₂泡沫为算例,对这些结果的物理图像做了简要的阐述,对它们的应用进行了具体的说明和分析。     

浅海遥感图片海底研究

利用海洋水色进行浅海水深反演,国内外已经提出了很多方法,并建立了各种模型。在他们的反演系统中,无一例外的要运用不同的水下测试仪器进行某些信息的提取,利用提取的信息确定参数,从而完成水深反演。在脱离任何水下测试仪器的情况下,仅通过卫星图片或航空图片提取浅海水深信息,利用海洋水色变化的基本原理,讨论了辐照度与波长以及水深的关系,模拟了浅海水下地形,并通过三维立体形式演示海底地貌。以遥感图片和数码照片为例,分别模拟了所拍摄地区的浅海海底概貌。结果表明,此方法具有一定的可行性,可以进行更深层次的研究,并可应用于航海安全保证、大陆架遥感测绘和环境检测等多个领域。     

The polynomial and linear time hierarchies in V0

We show that the bounded arithmetic theory V⁰ does not prove that the polynomial time hierarchy collapses to the linear time hierarchy (without parameters). The result follows from a lower bound for bounded depth circuits computing prefix parity, where the circuits are allowed some auxiliary input; we derive this from a theorem of Ajtai (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

人结肠及结肠腺癌组织的光学穿透深度和光衰减特性

利用反向倍增法（IAD），采用双积分球系统，研究了人正常结肠和结肠腺癌粘膜／粘膜下层以及正常结肠和结肠腺癌肌层／浆膜组织对630nm，680nm，720nm，780nm，810nm，850nm和890nm的钛宝石激光的光学穿透深度和光衰减特性。结果表明，正常结肠和结肠腺癌粘膜／粘膜下层以及正常结肠和结肠腺癌肌层／浆膜组织的光学穿透深度和总衰减系数都是随着激光波长的变化而变化的。正常结肠和结肠腺癌粘膜／粘膜下层组织的光学穿透深度的最大值都在890nm，其值分别为0．517cm和0．348cm；最小值都在680nm，其值分别为0．232cm和0．209cm。正常结肠和结肠腺癌肌层／浆膜组织的光学穿透深度的最大值都在890nm，其值分别为0．575cm和0．433cm；最小值都在680nm，其值分别为0．277cm和0．260cm。正常结肠和结肠腺癌粘膜／粘膜下层组织的总衰减系数的最大值都在890nm，其值分别为215cm^-1和229cm^-1；最小值都在780nm，其值分别为187cm^-1和209cm^-1。正常结肠和结肠腺癌肌层／浆膜组织的总衰减系数的最大值都在890nm，其值分别为213cm^-1和231cm^-1；最小值都在680nm，其值分别为193cm^-1和204cm^-1。     

(L)2样本深度的基本性质

本文讨论由L^2深度修正得到的L^2深度相应的样本深度的性质，得到了样本深度的相合性和渐近正态性，并证明了它在任意紧集上的一致相合性．最后，基于上述性质简要讨论了样本深度等高的一些性质．     

Influence of local waste burning on atmospheric aerosol properties in urban environment

Aerosols affect the radiative energy budget on both the regional and global scales. The wavelength-dependent aerosol optical depth (AOD) is a fundamental determinant of the amount by which extra-terrestrial incoming sunlight and outgoing terrestrial radiation are being attenuated in the atmosphere. The present study addresses the influence of local waste burning on aerosol characteristics, black carbon (BC) aerosol mass concentration and spectral solar irradiance using ground-based measurements over the tropical urban environment of Hyderabad, India. AOD has been observed to be maximum during burning days compared to normal days. Aerosol size spectra suggest bimodal distributions during pre-and post-burning periods and trimodal distributions during burning periods. Angstrom wavelength exponent estimated from spectral variation of AOD suggested dominance of accumulation mode particle loading during burning days compared to normal days. Diurnal variation of BC on normal days showed a broad nocturnal peak during ∼20:00 to ∼24:00 h with a maximum value of BC aerosol concentration of ∼14,000 ng m⁻³ whereas on local waste burning days enormous increases in BC concentrations have been observed with a peak at ∼60,000 ng m⁻³. Relative attenuation of global solar irradiance during burning days has been found to be of the order of 30% in the visible and 28% in the near-infrared regions. The results are discussed in detail in this paper.     

液体中光声热弹光穿透效应的研究

从光声热弹性的基本方程出发 ,在理论和实验上研究了液体在激光直接照射下产生超声波时 ,光穿透深度对声源的影响。在二维情况下 ,忽略热扩散效应 ,利用汉克积分变换法和最陡下降法解热扩散方程和波动方程 ,得出位移的解析表达式。讨论了光穿透深度对声源指向性的影响 ,并用数值计算方法和绘图软件画出光穿透深度对声源指向性影响的理论曲线图。最后 ,利用实验验证了理论结果。