用神经网络建立非线性系统模型研究

本文针对多层网络结构，运用递推预报误差（ＲＰＥ）算法对离散非线性系统进行辨识研究，作为应用实例，本文对一个工业实际进行了神经网络动态建模，研究结果表明，神经网络方法是用于带有非线性特性工业过程建模的有效方法。     

金属基体上YSZ过渡层及YBCO薄膜结构与沉积条件的关系

研究了两种在金属基体（ＨａｓｔｅｌｏｙＣ）上沉积的、以钇稳定的ＺｒＯ２（ＹＳＺ）为过渡层的ＹＢａ２Ｃｕ３Ｏ７－ｙ薄膜结构，并讨论了结构与沉积条件的关系。当沉积速率低时，ＹＳＺ层致密、均匀，存在织构取向，且与基体连接良好；而高速率沉积的ＹＳＺ层疏松，与基体结合差。ＹＢＣＯ薄膜的结构和性能与沉积时的基体温度相关。     

Pseudogap Phenomenon in Single Phase Hg-1223 Cuprate Superconductors

The single phase Hg-1223 cuprate superconductors have been successfully fabricated. The postannealing treatment under oxygen (O₂) gas and argon (Ar) gas with different annealing time was performed in order to obtain various hole density samples. These samples were used to study the pseudogap phenomenon in the normal phase. With the plot of ln[1/(T) – 1/_N(T)] against 1/T, three characteristic temperatures T*, T _S, and T _F were obtained, which describe the role of the pseudogap phenomenon. The magnitudes of the pseudogap were extracted from the slope of the stated plots. It is found that the three characteristic temperatures T*, T _S, and T _F change with the hole density linearly. The relationship between T* and T _C goes within T* = T*_op+₀ (1–T_C/T^max _C) , where T*_op and T _C ^max are the pseudogap opening temperature and the critical temperature for the optimal sample. It is also found that the pseudogap phenomenon only exists below the optimal regime in the hole doping phase diagram.     

The Paramagnetism Carried by Paramagnetic Ions and its Effect on the Superconductivity in High TC Superconductors

Extended Brillouin function with a revision is applied to describe the paramagnetism carried by the rare-earth Gd^{3 +} ions in GdBa₂Cu₃O₆₊ and the Re²⁺ ions in (Hg_0.9Re_0.1)Ba₂Ca₂Cu₃O_g+. We believe that the paramagnetism depends on the internal flux density of the sample instead of the applied field. At the field below H_cl the paramagnetism has no contribution to total magnetization; at the field over H_cl the paramagnetic magnetization has different values when in field-increasing and field-decreasing process. The width of the magnetization hysteresis loop M is broadened by the paramagnetism. The effect of the paramagnetism due to paramagnetic ions on the magnetization relaxation rate and the magnetization critical-current density J_c based on the Bean critical-state model is also discussed. The temperature dependence of the paramagnetism is shown in this paper.     

数字图像处理技术在导弹垂直装填中的应用研究

对舰载导弹垂直发射系统装填过程中存在的问题进行了分析,针对导弹装填效率低提出了计算机控制的“抗摇摆”解决方案,然后对计算机控制的“抗摇摆”系统的分系统即定位传感器部分进行了研究,重点研究了基于视频成像技术的导弹贮运发射箱空间位置坐标测量方法,并对其中的关键技术进行了探讨,给出了图像处理结果。实验表明,该方法具有抗干扰能力强,定位精度高等特点,能够满足导弹垂直装填过程定位要求。     

高放废液玻璃固化工艺冷试验装置的设计和验证试验

设计、安装了一套玻璃固化冷试验装置,作了多轮工艺冷试验,取得了一定的经验。本文介绍了装置的设计参数和工艺冷试验对设备的考验结果。     

Basic probabilistic considerations on safety of prestressed concrete pressure vessels

The purpose of the present study is to lay the foundation for the probabilistic safety analysis pertinent to prestressed concrete pressure vessels of nuclear generating stations. We place a major emphasis on the consistency with which various aspects of structural and statistical significance are analyzed and then combined into a probabilistic formulation amenable to practical risk assessment and assurance. In particular (1) prestressed concrete pressure vessels subjected to loads of various temporal nature are considered, (2) the probabilistic algebra used in risk assessment is basically that of the second moment-first order approximation, and (3) the method thus established is applied to reliability analysis of prestressed concrete reactor vessels (PCRVs) to estimate the probability level of ultimate failure. The result of the present study indicating the probability level of the vessel reliability depends entirely on the assumptions concerning statistical aspects of loading conditions and resisting capacities of the vessel and on the approximations in relation to stress and structural analysis and ultimate failure conditions. Therefore, the resulting probability values are illustrative and comparative rather than factual at this time. The authors are solely responsible for the content of this paper which does not represent the official view of the USAEC.     

Preparation of β-TCP with high thermal stability by solid reaction route

Starting from commercial materials, -TCP powder was prepared by a conventional solid reaction route. Using DTG, TG and DTA, the mass change and the heat flow during heating of the commercial powder mixture were tested. The phase evolution at each step of the heating was monitored using XRD analyses. Based on the tests and the analyses the reaction details were analyzed. The -TCP powder prepared in this study has high thermal stability. The phase transition temperature from to was determined to be 1350°C, 200°C higher than commercial -TCP powder (Plasma Biotal). The high phase transition temperature was due to Mg trace in the starting materials.     

Studies of effect of phase volume ratio on transfer of ionizable species across the water/ 1,2-dichloroethane interface by a three-electrode setup

The electrochemical behavior of pyridine distribution at the water/1,2-dichloroethane interface with variable phase volume ratios (r = Vo/Vw) was investigated by cyclic voltammetry. The system was composed of an aqueous droplet supported on a Ag/AgCl disk electrode covered with an organic solution or an organic droplet supported on a Ag/AgTPBCl disk electrode covered with an aqueous solution. In this way, a conventional three-electrode potentiostat can be used to study an ionizable compound transfer process at a liquid/liquid interface with a wide range of phase volume ratios (from 0.0004 to 1 and from 1 to 2500). Using this special cell we designed, only very small volumes of both phase were needed for r equal to unity, which is very useful for the investigation of the distribution of ionizable species at a biphasic system when the available amount of species is limited. The ionic partition diagrams were obtained for different phase volume ratios.     

Molecular Tissue Engineering：Concepts,Status and Challenge

Tissue engineering has confronted many diffculties mainly as follows:1) How to modulate the adherence,proliferation,and oriented differentiation of seed cells,especially that of stemcells.2)Massive preparation and sustained controllable delivery of tissue inducing factors or plasmid DNA,such as growth factors,angiogenesis stimulators,and so on.3) Development of “intelligent biomimetic materials” as extracellular matrix with a good superficial and sturctural compatibility as well as biological activity to stimulate predictable,controllable and desirable responses under defined conditions.Molecular biology is currently one of the most exciting fields of research across life sciences,and the advances in it also bring a bright future for tissue engineering to overcome these difficulties.In recent years,tissue engineering benefits a lot from molecular biology.Only a comprehensive understanding of the involved ingredients of tissue engineering(cells,tissue inducing factors,genes,biomaterials) and the subtle relationships between them at molecular level can lead to a successful manipulation of reparative processes and a better biological substitute.Molecular tissue engineering,the offspring of the tissue engineering and molecular biology.has gained an increasing importance in recent years.It offers the promise of not simply replacing tissue,but improving the restoration.The studies presented in this article put forward this new concept for the fist time and provide an insight into the basic principles,status and challenges of this emerging technology.