Recent investigations on some cubic Laves phase compounds of rare earth and transition metals

Pseudobinary alloy, Tb_0·27Dy_0·73Fe_2−δ , belonging to C-15 cubic Laves phase having MgCu₂-type structure, possesses large magnetostriction and high magnetomechanical coupling coefficient. The advantages of this material over existing piezoelectric materials, particularly for SONAR applications, are highlighted. Recent results on the influence of cobalt (Co) on magnetic and magnetomechanical properties of Tb_0·27Dy_0·73Fe₂ are discussed.     

粒界缓冲型展宽效应对PTC材料温度系数的影响

本文利用相变扩张理论分析了粒界缓冲型展宽效应对BaTiO_3系PTC陶瓷的介电系数及温度系数a_r的影响,指出了晶粒尺寸和温度系数的关系。     

紧凑式换热面瞬态实验中的全程直接配比法

在紧凑式换热面的瞬态实验中，为获得准确的实验结果，不仅要建立符合试验工况的理 论解，而且还要选择合适的配比方法，以便尽可能减小测量误差对配比结果的影响．本文就瞬态实 验的配比，提出了一种新的基于计算机的全程直接配比法，由于它采用了所有可用测试点进行配 比并且其理论解与实测值的配比误差是通过最小搜索步长来控制的，因此，实验结果的准确性和 可靠性优于通常应用的间接配比法和选点配比法．     

先进控制在环管法聚丙烯装置中的应用

以九江石油化工总厂70kt/a聚丙烯装置产率控制为例,介绍先进过程控制系统在石油化工装置上的应用情况。     

Explosive Random‐Coefficient AR(1) Processes and Related Asymptotics for Least‐Squares Estimation

Abstract. Large sample properties of the least‐squares and weighted least‐squares estimates of the autoregressive parameter of the explosive random‐coefficient AR(1) process are discussed. It is shown that, contrary to the standard AR(1) case, the least‐squares estimator is inconsistent whereas the weighted least‐squares estimator is consistent and asymptotically normal even when the error process is not necessarily Gaussian. Conditional asymptotics on the event that a certain limiting random variable is non‐zero is also discussed.     

铁铝酸盐复合膨胀水泥化学预应力机理及其应用研究

本文阐述铁铝酸盐自应力混凝土的主要物理力学特征.研究了限制膨胀应变与配筋率之间的定量函数关系.通过正交试验和方差分析,确定了复合外加剂对其性能的影响.针对其在自应力管中的应用,提出多层中空圆柱理论计算模型,按弹性理论计算出自应力管初始应力分布规律.对比以前的线性理论计算误差,给出相应的修正系数.本文对类似的自应力混凝土,具有普遍的指导意义.     

直接空冷系统冬季启动运行浅析

介绍漳山发电ACC冬季启动，运行调整，冬季保护，停机注意事项，引发人们对ACC机组冬季安全运行的思考与讨论。     

Analysis of low load transients for the Vandellòs-II NPP: Application to operation and control support

The Technical University of Catalonia (UPC) has been jointly working with the Asociación Nuclear Ascó-Vandellòs (ANAV) for a number of years in order to establish, qualify and use best estimate (BE) models for the reactors under the control of ANAV. ANAV is the consortium that is responsible for operation of the Ascó and Vandellòs-II reactors. The reactors are Westinghouse-design three-loop PWRs with an approximate electrical power of 1000 MW. The existing integral plant models for each plant are currently used for many different purposes among which are support of plant operation and control. Quite a number of studies have been done in order to improve both safety and plant competitiveness. Most of these dynamic analyses were carried out in relation to transients starting at nominal full power or at least, very close to full power. This paper develops a specific use of the Vandellòs-II plant model for operation and control support at low power involving new ranges of system actuation parameters. It also examines scenarios that are somewhat different from those typically analysed. The study starts showing the results of an assessment case, which is a start-up test and provides some additional qualification, and subsequently attempts to establish calculations to support both an improvement in feed water controls and to set up operating recommendations for low-load manual operation of feed water turbo-pump. Both results hopefully, will produce an outcome, which leads to an improvement in safety and reduces reactor trip probability.     

科技论文摘要英译策略研究——以《中国钨业》摘要英译为例

科技论文摘要属典型的信息类语篇,其英译的预期功能是向译文读者传播科研成果。译者应在充分了解汉英两种语言在语用、逻辑和句法差异的基础上,灵活进行相应的变通,使译文做到语言通顺自然、逻辑层次清楚、措辞精确严谨。     

Robust estimation for circular data

The problems arising when there are outliers in a data set that follow a circular distribution are considered. A robust estimation of the unknown parameters is obtained using the methods of weighted likelihood and minimum disparity, each of which is defined for a general parametric family of circular data. The class of power divergence and the related residual adjustment function is investigated in order to improve the performance of the two methods which are studied for the Von Mises (circular normal) and the Wrapped Normal distributions. The techniques are illustrated via two examples based on a real data set and a Monte Carlo study, which also enables the discussion of various computational aspects.