CO_2、NH_3对YBa_2Cu_3O_(7-x)的结构及超导电性的影响

以热重分析(TGA)、电阻测量和X射线衍射分析等方法,研究了CO_2与NH_3对YBa_2Cu_3O_(7-x)超导体结构稳定性及超导,电性的影响。当温度低于373K时,CO_2对YBa_2Cu_3O(7-x)的结构和超导电性无影响;当温度为523K时,CO_2使YBa_2Cu_3O_(7-x)的Tc下降;温度高于703K时,CO_2将很快破坏YBa_2Cu_3O_(7-x)的结构,并产生化学反应,生成新的化合物,在CO_2中存在的O_2与N_2对YBa_2Cu_3O(7-x)与CO_2的反应及反应产物的影响有较大差异。NH_3对YBa_2Cu_3O(7-x)结构稳定性的影响不大。     

WCDMA中的关键技术

WCDMA关键技术并不是与IS-95、CDMA2000相比WCDMA系统特有的技术,而是在WCDMA协议框架范围内对系统性能有重要影响的技术,如果没有这些关键技术,WCDMA将达不到预期的目标。     

电子信息与工程控制学院北京市光电

工业大学电子信息与工程控制学院北京市光电子技术实验室,北京工业大学电子信息与工程控制学院北京市光电子技术实验室 北京100022,北京100022,北京100022,北京100022,北京100022,北京100022,北京100022,北京100022,北京100022悬臂梁;;可调谐垂直腔面发射激光器运用光学传输矩阵和有限元方法对波长可调谐垂直腔面发射激光器(VCSELs)的波长调谐范围     

比较优势发展战略与中国半导体产业的发展

针对当前我国半导体产业界对于未来发展战略的选择持有的两种不同观点,本文提出遵循“比较优势发展战略”发展我国半导体产业的观点。文章首先介绍了“比较优势”理论及其在后进地区半导体产业发展中的动态应用演变模式;然后具体分析了全球半导体产业分工发展及要素禀赋结构在产业中的演变以及由此带来的产业升级过程;并以我国台湾半导体产业30年来成功发展为例,说明遵循“比较优势发展战略”有利于半导体产业成功崛起;文章最后对我国大陆如何利用“比较优势”理论发展半导体产业做了一定探讨。     

美国和日本国家创新系统演进中的军民一体化及两用政策寓意

军民一体化是当今世界各国国家创新系统演进的共同趋势，本文特别分析了美国和日本国家创新系统演进中的军民一体化模式，从而得出其中蕴含的两用政策寓意，并对两用政策内涵进行具体剖析。     

Sliding mode control for active magnetic bearing system with flexible rotor

This paper presents the analysis and control of active magnetic bearing (AMB) systems with a flexible rotor. A sliding mode controller design scheme is proposed to compensate for the nonlinear effects of the AMB system. A nonlinear model of the AMB system with an electromagnetic actuator and a flexible rotor is proposed to facilitate the present system analysis and controller design. This nonlinear model takes into account the dynamics of the flexible rotor, the characteristics of the nonlinear electromagnetic suspended system, and the contact force between the auxiliary bearing and the shaft. This study also considers the auto-centering control of the AMB system when subjected to disturbances and variations in the system parameters. The numerical results show that the system exhibits a periodic motion and demonstrates high accuracy and robustness when operating under sliding mode control.     

动态全参数自调整BP神经网络预测模型的建立

本文从减少干预的思想出发，提出了BP神经网络动态全参数自调整学习算法，使得隐层节点和学习速率的选取全部动态实现，实现了学习速率和网络的适应能力，最后又将改善后的BP神经网络应用到经济领域中，得到了比常规经济学模型更优的效果。     

万寿竹六个居群的核型研究

本文研究了在云南境内的万寿竹Disporum cantoniense (Lour．)Merr．从滇东南经滇中到滇西 北不同居群间的核型变异。该种的染色体数目较为稳定，2n=14，没有观察到不同数目的变异。六个 居群的不对称性均属于3B型，但各个居群的核型结构表现出一定的差异，核型间随体位置和数目的不 同以及同源染色体的杂合性是居群间变异的主要特征，这种种内不同居群间核型的变异或许与该种的地理分布及生境有一定的相关性。     

Biological and Biochemical Potential of Sea Snake Venom and Characterization of Phospholipase A<Subscript>2</Subscript> and Anticoagulation Activity

This study is designed to isolate and purify a novel anti-clotting protein component from the venom of Enhydrina schistosa, and explore its biochemical and biological activities. The active protein was purified from the venom of E. schistosa by ion-exchange chromatography using DEAE-cellulose. The venom protein was tested by various parameters such as, proteolytic, haemolytic, phospholipase and anti-coagulant activities. 80 % purity was obtained in the final stage of purification and the purity level of venom was revealed as a single protein band of about 44 kDa in SDS-polyacrylamide electrophoresis under reducing conditions. The results showed that the Potent hemolytic activity was observed against cow, goat, chicken and human (A, B and O positive) erythrocytes. Furthermore, the clotting assays showed that the venom of E. schistosa significantly prolonged in activated partial thromboplastin time, thrombin time, and prothrombin time. Venomous enzymes which hydrolyzed casein and gelatin substrate were found in this venom protein. Gelatinolytic activity was optimal at pH 5–9 and ¹H NMR analysis of purified venom was the base line information for the structural determination. These results suggested that the E. schistosa venom holds good promise for the development of novel lead compounds for pharmacological applications in near future.     

基于RTL行为模型的测试产生及时延测试方法(英)

寄存器传输级(RTL)测试产生及时延测试是当今集成电路(IC)测试技术中亟待解决的问题和研究的热点.首先从IC逻辑测试的测试产生和IC时延测试方法这两个方面系统地综述了测试产生和时延测试领域迄今为止的主要研究成果.在RTL行为描述的测试产生方面,提出了新的RTL行为模型的描述方法:行为阶段聚类描述,并提出了基于聚类的测试产生技术.将这些技术集成到RTL级ATPG系统ATCLUB中,在提高测试产生效率及缩短测试长度方面效果显著.在IC时延测试方面,提出了一种新的可变双观测点的时延测试方法。基于该方法提出了新的时延故障诊断方法,实现和完善了可变双观测点的时延测试系统DTwDO.DTwDO提供了从时延测试到故障诊断等一系列测试工具,有效减少了测试通路数,提高了故障覆盖率,并有很高的故障定位成功率.