采用扫描电镜的ECP技术分析人工合成金刚石晶体中的晶体缺陷

本文应用扫描电镜的ＥＣＰ技术对人造金刚石晶体表面的位错密度，进行了实验分析，并同位错蚀坑分析技术的测量结果进行了比较，结果表明，如采用临界束流强度作为描述ＥＣＰ本征衬度的参数，则它同位错密度间存在明显定量的数学关系，因此上述临界束流强度可用来评价晶体中位错密度的相对变化。     

可溶高分子负载钯催化剂对于硝基苯加氢反应催化性能的研究

以醇或水溶性高分子（聚乙烯吡咯烷酮，ＰＶＰ；乙基纤维素，ＥＣ；聚乙烯醇，ＰＶＡ；羧甲基纤维素钠，ＣＭＣＮａ）为载体，制备了四种可溶高分子负载钯催化剂。无机碱的存在对反应呈明显的加速效应。在少量Ｋ２ＣＯ３存在下，ＥＣ－ＰｄＣｌ２和ＰＶＰ－ＰｄＣｌ２对于硝基苯的催化加氢具有非常高的活性，最高活性＞２３０ｍｏｌＨ２／ｍｏｌＰｄ·ｍｉｎ，即大于５１５０ｍｌＨ２／ｍｍｏｌＰｄ·ｍｉｎ，该数值是已知文献报道的最好结果。详细考察了各种碱、Ｋ２ＣＯ３用量、溶剂以及反应温度对ＰＶＰ－ＰｄＣｌ２催化硝基苯加氢性能的影响。     

阴极射线管显示器不同屏显字符形状和颜色特征的识别工效的比较研究

本实验研究用数字、汉字、飞机图标和几何图形比较了颜色编码、形状编码及颜色和形状双重编码的检测工效。在阴极射线管（ＣＲＴ）显示器屏幕的９个固定位置（３×３矩阵）上同时显示同一形状不同颜色、同一颜色不同形状或颜色和形状都不相同的３、６或９个字符，让被试按颜色、形状或同时按颜色和形状找出一目标字符，并按压键标数字与所找字符显示位置号相同的键。每个字符在各个位置的显示概率是相等的，显示的先后次序是随机的。字符的显示、目标字符的检测时间和错误率由计算机系统程序控制，实时计算和打印记录。结果表明，就检测工效而言，颜色编码优于颜色和形状双重编码，后者又优于形状编码；目标字符的检测时间随同时显示字符的数量的增加而增长，并得到了从同时显示的３、６、９个字符中按不同特征检测目标字符的搜索一识别时间和包括按键操作在内的目标检测时间。     

Coordinated induction of plasminogen activator inhibitor-1 (PAI-1) and inhibition of plasminogen activator gene expression by hypoxia promotes pulmonary vascular fibrin deposition

PURPOSE: In a rabbit model, transposition of a muscle pedicle flap to an ischemic hind limb has been shown to result in the development of new blood vessels that connect the arterial circulation of the flap to the circulation of the limb. The hypothesis that exogenous recombinant basic fibroblast growth factor (bFGF) would enhance the development of this new blood supply was examined and the regulation of bFGF in this process was investigated. METHODS: The right common iliac artery was ligated in 12 male New Zealand white rabbits. An abdominal wall muscle flap based on the left inferior epigastric artery was transposed to the right thigh. bFGF in phosphate-buffered saline (PBS) at 3 ng/h (n = 6), or PBS alone (n = 6), was infused for 7 days via mini-osmotic pumps with an infusion catheter positioned at the flap-muscle interface. The flap-muscle interface was immunostained with anti-alpha-actin antibody to determine blood vessel density (number of vessels/mm) and with anti-bFGF antibody to evaluate bFGF distribution. RNA was isolated from these sections, and polymerase chain reaction (PCR) was used to examine endogenous bFGF messenger RNA (mRNA) expression. RESULTS: Blood vessel density was significantly increased in animals receiving exogenous bFGF (22. 0 +/- 10.6 vessels/mm vs. 10.7 +/- 8.8 vessels/mm, P =.009). In the controls, neovessels were arranged in clusters with endogenous bFGF concentrated around these clusters. In bFGF-treated animals, vessels were diffusely scattered throughout the flap-limb interface, corresponding to the distribution pattern of infused bFGF. There was no difference in bFGF mRNA expression between the control and the bFGF-treated groups. CONCLUSION: Exogenous bFGF infusion significantly augmented new blood vessel development at the flap-limb interface. Endogenous bFGF was up-regulated around the newly developed microvessels in control animals, and vessel growth correlated with the diffuse distribution of exogenous bFGF, implicating bFGF as an important factor in angiogenesis. Exogenous bFGF did not affect bFGF mRNA expression, suggesting that the regulation of bFGF is not under autocrine control.     

一种新的薄壁铜管切割方法

介绍了一种新的直型刀具切割薄壁铜管的方法，提供了其主要参数的计算．     

Emission cross section and fluorescence efficiency of Nd-pentaphosphate

The room-temperature cross sections for the Nd³⁺⁴F_{3/2}levels to the⁴I_{11/2}and⁴I_{9/2}manifolds (lower laser state and ground state, respectively) in NdP5O14are measured by two spectroscopic methods. A value for the largest cross section ofsigma(R_{1} - Y_{2}) = 1.7 times 10^{-19}cm²is found. The highest effective cross section, resulting from superposition of two lines at 1.051 μm, gives a laser gain per Nd ion which is about 2/3 of the maximum gain in YAG:Nd. The relative branching ratio into the⁴I_{11/2}and⁴I_{9/2}manifolds is 0.65:0.35. Comparison of the integrated cross sections with the measured lifetime for 1-percent Nd in LaP5O14indicates a combined efficiency <0.1 for the remaining transitions, namely radiative decay into the⁴I_{13/2}and⁴I_{15/2}manifolds and multiphonon quenching. A measurement of temperature dependence of fluorescence lifetime supports this last result.     

解非串并联系统可靠性最优化问题的一个简捷算法

本文分析了非串并联的桥式网络和混联网络在最佳冗余分配方面的特点,提出了以桥式 和混联网络作为典型环节的复杂系统可靠性最优化问题的简化原则,并推广应用文献[1]的简 捷算法来解复杂系统可靠性最优化问题.     

Application of the theory of optimal experiments to adaptive electromagnetic-induction sensing of buried targets

A mobile electromagnetic-induction (EM I) sensor is considered for detection and characterization of buried conducting and/or ferrous targets. The sensor maybe placed on a robot and, here, we consider design of an optimal adaptive-search strategy. A frequency-dependent magnetic-dipole model is used to characterize the target at EMI frequencies. The goal of the search is accurate characterization of the dipole-model parameters, denoted by the vector /spl Theta/; the target position and orientation are a subset of /spl Theta/. The sensor position and operating frequency are denoted by the parameter vector p and a measurement is represented by the pair (p, O), where O denotes the observed data. The parameters p are fixed for a given measurement, but, in the context of a sequence of measurements p may be changed adaptively. In a locally optimal sequence of measurements, we desire the optimal sensor parameters, p/sub N+1/ for estimation of /spl Theta/, based on the previous measurements (p/sub n/, O/sub n/)/sub n=1,N/. The search strategy is based on the theory of optimal experiments, as discussed in detail and demonstrated via several numerical examples.     

颌骨重建中的图像分割和轮廓对应及分支问题

根据人体颌骨的形状特征,提出一系列有针对性的方法,在CT断层数据的基础上重建三维表面模型．研究的内容包括医学图像的分割和从轮廓线重建表面两个方面．首先,采用一种称为“非种子区域分割”方法提取物体的轮廓线;然后,建立一条反应颌骨走向的弓形“参照基准线”,充分利用轮廓线相对于它的“归一化位置”信息解决表面重建中的对应和分支问题;同时考虑相邻层的影响,使生成的表面更加光滑、自然．最后,提出“多阶凸包点对应匹配”的思想,用分层分段迭代的方法拼接三角面片．     

Synthesis and biocompatibility of porous nano-hydroxyapatite/collagen/alginate composite

Porous nano-hydroxyapatite/collagen/alginate (nHAC/Alginate) composite containing nHAC and Ca-crosslinked alginate is synthesized biomimetically. This composite shows a significant improvement in mechanical properties over nHAC material. Mechanical test results show that the compressive modulus and yield strength of this composite are in direct proportion to the percentage of Ca-crosslinked alginate in the composite. Primary biocompatibility experiments in vitro including fibroblasts and osteoblasts co-culture with nHAC/alginate composite indicated the high biocompatibility of this composite. Therefore the composite can be a promising candidate of scaffold material for bone tissue engineering.