Influence of Complex Refractive Index on Diffuse Reflection of Biological Tissues

Complex refractive indices are introduced to solve various boundary questions at the interfaces when modelling light migration within heterogeneous tissues. Combined with the complex refractive index, Fresnel‘s formulaeare used to describe the reflection and transmission at the interfaces between two heterogeneous tissues layers.Using the Monte Carlo method, the influence of the complex refractive index on diffuse reflection of semi-infinite biological tissues is discussed. The results show that neglecting the imaginary part of the refractive index of tissues will bring a major deviation in the diffuse reflection of semi-infinite biological tissues when its emitting point is apart from the incident point.     

线光束照射下局部病变组织背散射场角分布研究

将内含异质层的半无限生物组织作为研究线光束照射下局部病变组织背散射场的近似模型，在此基础上，引入倍加算法对线光束照射下局部病变组织背散射场角分布进行数值计算。根据数值计算结果，分析了不同组织层几何参量和光学参量对背散射场角分布的影响，结果表明：“病变组织层对背散射场中小角度光的影响明显大于对大角度光的影响；背散射场的角分布对病变组织的几何参量(埋藏深度和光学厚度)较为敏感，而对病变组织光学参量亦即病变组织性质的差异敏感度较低。”同时还对含肿瘤的乳房组织的背散射场角分布进行了计算和分析，为将背散射场角分布应用于组织内隐藏异物的无创伤诊断提供了理论参考。     

Transfer color to night vision images

Night vision technology enables human beings to operat at night. Low light level imaging and infrared imaging are two key technologies in night vision field. However the images obtained through the night vision imaging systems are monochromatic, this hinders observers from interpreting the scene well. In order to improve targe detection and identification abilities, color night vision technology is being pursued as an effective method fo solving the problem. The main methods of realizing color…     

Color fusion of SAR and FLIR images using a natural color transfer technique

Fusion of synthetic aperture radar (SAR) and forward looking infrared (FLIR) images is an important subject for aerospace and sensor surveillance. This paper presents a scheme to achieve a natural color image based on the contours feature of SAR and the target region feature of FLIR so that the overall scene recognition and situational awareness can be improved. The SAR and FLIR images are first decomposed into steerable pyramids, and the contour maps in the SAR image and the region maps in the FLIR image are calculated. The contour and region features are fused at each level of the steerable pyramids. A color image is then formed by transferring daytime color to the monochromic image by using the natural color transfer technique. Experimental results show that the proposed method is effective in providing a color fusion of SAR and FLIR images.     

理想气体一维不定常流自模拟运动的基本微分方程

将一维不定常流自模拟函数推广到一般形式，结合量纲理论和流体力学基本运动方程，导出总能量为常数情况下的理想气体一维不定常流自模拟运动基本微分方程组.该理论模型表明，由流体速率u和自模拟面速率r·〖DD)]组成一个无量纲特性参数L，用L作自变量时理想气体一维不定常流自模拟运动的规律具有常微分方程的最简数学形式.该模型克服了点爆炸Taylor自模拟温度函数原点附近趋于无穷大的问题，具有重要意义. 关键词： 理想气体 自模拟运动 Taylor模型     

Synthesis of Large Quantity Single—Walled Carbon Nanotubes by Arc Discharge

We report on a new method to prepare large quantity single-walled carbon nanotubes(SWCNTs) with high purity.Using a Y-Ni powder composite graphite rod as an anode,at a given angle with the high-purity graphite cathode rod,a cloth-like deposit can be obtained by dc arc discharge in helium at high temperature,which contains about 60% SWCNTs.In this way,we can obtain a deposit of more than one gram in ten minutes.Transmission electron microscopy and Raman scattering have been used to observe the structure and morphology of the SWCNTs.     

Bragg光纤光栅用作滤波器时的输出光脉冲波形分析

对光纤光栅用作接收端光噪音滤波器进行了详细的理论分析,计算了通信系统中矩形光脉冲信号经“强”、“弱”Bragg光纤光栅滤波器后的输出光脉冲波形,同时也计算了矩形光脉冲信号经匹配光滤波器、现行光通信系统中常用F-P滤波器的输出光脉冲波形,对四种滤波器的输出光脉冲波形进行了分析和比较,并分析了输出信号在抽样判决时的码间干扰情况,从输出波形分析认为,光纤光栅用做接收端噪音滤波器比F-P滤波器具有更大的优越性.     

毛细管真空紫外线辐射源

稀有气体中的毛细管放电的共振辐射在真空紫外区,可被用作真空紫外辐射源。本文讨论了无窗式毛细管真空紫外辐射源的结构设计,并用实验测定了它的辐射特性。由于HeⅡ(303.8)共振辐射对光电子谱研究最为有用,实验表明为了获得强的HeⅡ(303.8)线,He的工作气压应小于0.1乇。总的HeⅡ(303.8)约为3.2×10~(11)光子/秒。此类毛细管真空紫外光源可用于表面研究及真空紫外单色仪的波长定标。     

数字三色条纹相移形貌投影栅线法

基于投影栅线的三色条纹相移算法与投影栅线法相结合,提出一种数字三色条纹相移形貌投影栅线法.此法是对时间相移法的改进,只需一幅三色条纹图,就可利用简单的三光强相移算法完成物体表面的形貌重建;不需要相移装置而误差较小,成本较低,简易实用,将有利于推广到动态实时分析.实验证明,此法是正确可行的.     

液体和非晶态Ni64B36合金结构的从头算分子动力学模拟

运用从头算分子动力学模拟了液体以及猝冷后形成的非晶态Ni₆₄B₃₆合金体系, 得到了它们的对相关函数、结构因子、键对分析方面的结构信息, 与实验结果相当一致; 结果表明, 猝冷得到的合金性质与液体合金性质相似, 为非晶态结构. B原子多数以B—B双原子成键形式分散于Ni原子构成的骨架中. 电子态密度分析表明, Ni 3d电子最活泼, 因此在合金中Ni为活性位. 轨道电荷分析从电子结构角度揭示了在NiB 催化剂中B作为修饰剂的机理.