钕电解阳极过电位的测定

用慢扫描示波法测定了钕电解的阳极过电位 .考察了温度、阳极电流密度、Nd2 O3添加量、电解质组成等因素对阳极过电位的影响 ,探讨了降低阳极过电位的可能途径 .结果表明 ,阳极过电位随阳极电流密度的增加而增大 ,随温度的升高而减小 ,一定范围内 ,阳极过电位与阳极电流密度的对数呈线性关系 ,满足塔菲尔方程 ;电解质中LiF和Nd2 O3浓度增加 ,阳极过电位降低 ;适当控制阳极电流密度、升高温度、增加电解质中LiF和Nd2 O3的浓度并尽可能减小极间距 ,均有利于降低阳极过电位     

纳米技术在中药开发中的应用

本文综述了纳米科技与中药制剂相结合的发展，阐述了纳米中药的概念、特性，介绍了纳米中药的制备技术，另外探讨了收集纳米粒子的方法，最后，着重展望了纳米技术在中药制剂中广泛的应用前景。     

Sol-gel Preparation and Preliminary in vitro Evaluation of Fluorapatite／Hydroxyapatite Solid Solution Films

Fluorapatite/hydroxyapatite solid solution has better biological properties than other apatites, especially used as films or coatings. In this work, sol-gel preparation and in vitro behavior of fluorapatite/hydroxyapatite solid solution films on titanium alloy were investigated. Ca(NO3)2-4H20 and PO(OH)x(OEt)3-x were selected as precursors, and hexafluorophosphoric acid (HPFo) was used as a fluorine containing reagent. The Ca and P precursors were mixed with HPFo to keep the Ca/P molar ratio 1.67. The mixtures refluxed for 12 h were used as dipping sols for the preparation of the films. The phase of the films obtained at 600℃ was apatite. The F contents in the films increased with the concentrations of HPF6 in the dipping sols. The solid solution films were shown to have better stability than hydroxyapatite films, and a reasonably good bioactivity in the in vitro evaluation.     

环境试验与可靠性试验的关系

从环境试验和可靠性试验的相关标准入手，详细论述了两者之间的相互关系与区别：互为补充，互为依存，共同发展，共同为保障产品的环境适应性和使用可靠性发挥作用。最后阐述了加强自然环境试验的重要性，它是检验实验结果的基本标准。     

Synthesis, characteristics and oxygen-sensitive properties of SrMgxTi 1 − xO3 nanocrystals

SrMg_xTi_{1 - x}O₃ nanocrystals (x = 0.1–0.6) were synthesized by the stearic acid gel method. Powder samples were characterized by X-ray diffraction and X-ray photoelectron (XP) spectroscopy. The results showed that the lattice parameter a and the O 1s XP spectrum changed not only with the Mg content x but also with the grain size d of the samples. The conductivity of a thick film specimen fabricated on an aluminium oxide wafer was investigated in a nitrogen—oxygen atmosphere.     

溶胶－凝胶法制备Pb（Zr，Ti）O_3玻璃陶瓷过程中的结构变化

本文介绍溶胶－凝胶法制备均匀ＰｂＺｒ－Ｔｉ－Ｂ－Ｓｉ凝胶玻璃，并通过适当热处理在凝胶玻璃中原位生长Ｐｂ（Ｚｒ；Ｔｉ）Ｏ３微晶的新工艺·利用ＩＲ谱考察了凝胶玻璃中的元素键合结构随温度的变化．结合热分析和ＸＲＤ；ＳＥＭ技术，研究了Ｐｂ（Ｚｒ，Ｔｉ）Ｏ３微晶在凝胶玻璃中的生长过程及该材料的结构特点．发现Ｐｂ２（Ｚｒ，Ｔｉ）２Ｏ６＋ｘ立方焦绿石介稳过渡相的纳米微晶首先出现于该体系中，并在更高的温度下先后完全转变成三方和四方Ｐｂ（Ｚｒ，Ｔｉ）Ｏ３钙钛矿相．电子显微观察结果表明，该工艺制备的Ｐｈ（Ｚｒ；Ｔｉ）Ｏ３玻璃陶瓷具有均匀的细晶结构．     

Flow reversal in the descending aorta: a guide to intraoperative assessment of aortic regurgitation with transesophageal echocardiography

This study assessed the value of biplane transesophageal echocardiographic assessment of diastolic flow reversal in the descending aorta as an alternative to Doppler color flow imaging in determining severity of aortic regurgitation. In 45 patients undergoing cardiac operations, the severity of aortic regurgitation was assessed by semiquantitative grading of the width of the Doppler color flow regurgitant jet relative to the left ventricular outflow tract, and the presence of diastolic flow reversal was assessed with pulsed-wave Doppler measurements at three sites in the descending aorta. In four patients, the diastolic flow reversal method was the only available form of assessment because of inadequate visualization of the left ventricular outflow tract beneath a mitral valve prosthesis. Diastolic flow reversal in the descending aorta was not observed in patients without aortic regurgitation and was always present in patients with severe aortic regurgitation. Aortic valve replacement successfully eliminated descending aortic flow reversal in all 19 patients in whom it was present before valve replacement. Identification of diastolic flow reversal at multiple sites in the descending aorta with biplane transesophageal echocardiography helps to confirm the presence of severe aortic regurgitation and can serve as an alternative method of assessment when visualization of the left ventricular outflow tract is impaired.     

建筑容积率对地价影响规律及修正方法研究

在分析建筑容积率对土地价格影响的作用机制和规律的基础上，针对目前土地估价工作中，容积率修正系数确定存在的问题，提出新的容积率修正思路和方法。     

新型缆用热熔胶的研制

分析了通信线缆用 YH- 4热熔胶组成原料的性能和作用 ,找出影响耐环境高温性能的主要原因 ,并对新研制出的耐环境高温性能 YH- 5热熔胶作了一些分析和探讨 .     

U(Ⅳ)-U(Ⅵ)同位素交换反应动力学研究 Ⅰ.Fe~(2+)对U(Ⅳ)-U(Ⅵ)同位素交换反应的催化作用

一、前言由于U(IV)-U(VI)同位素交换体系具有相当大的同位素效应和很好的稳定性,并且容易实现两相回流,这对于分离U同位素的工业应用都是十分有利的。但是,U(IV)-U(VI)同位素交换反应速度非常慢,常温下H~+浓度为1.0—4.0 mol/l时,速度常数为1.0×10~(-4)l~2/mol·s。因此要用U(IV)-U(VI)交换体系浓缩铀同位素,必须研究U(IV)-U(VI)交换反应动力学,找到加快交换反应的方法。