快速凝固Cu-Al-Ni合金的记忆性能及时效稳定性

采用快速凝固淬火法获得Cu-Al-Ni合金带,并对其合金的转变特性、记忆性能、时效对临界点的影响以及应变与回复率的关系进行了研究,为了进一步开发和应用提供了依据。     

Long‐memory dynamic Tobit models

We introduce a long‐memory dynamic Tobit model, defining it as a censored version of a fractionally integrated Gaussian ARMA model, which may include seasonal components and/or additional regression variables. Parameter estimation for such a model using standard techniques is typically infeasible, since the model is not Markovian, cannot be expressed in a finite‐dimensional state‐space form, and includes censored observations. Furthermore, the long‐memory property renders a standard Gibbs sampling scheme impractical. Therefore we introduce a new Markov chain Monte Carlo sampling scheme, which is orders of magnitude more efficient than the standard Gibbs sampler. The method is inherently capable of handling missing observations. In case studies, the model is fit to two time series: one consisting of volumes of requests to a hard disk over time, and the other consisting of hourly rainfall measurements in Edinburgh over a 2‐year period. The resulting posterior distributions for the fractional differencing parameter demonstrate, for these two time series, the importance of the long‐memory structure in the models. Copyright © 2006 John Wiley & Sons, Ltd.     

消极心理因素对急行跳远踏板准确性的影响

急行跳远踏跳的准确性直接决定着运动员试跳的成绩 .心理因素是影响踏跳准确性的重要因素 ,包括积极因素和消极因素两种 .其中消极的心理因素对急行跳远踏板的准确性的影响十分重要 ,文章就此问题进行分析探讨 .     

对称正则长波方程的指数吸引子

考虑了对称正则长波方程的整体快变动力学。证明了该方程有关的非线形半群的挤压性质和指数吸引子的存在性。     

Discussion on Improvement of Toxicological Pathology Study

Toxicological pathology plays a key role in drug safety assessment. To enhance the research level of toxicological pathology, the following studies should be carried out urgently: setting up a standard operation procedure (SOP) for toxicological pathology assessment; emphasizing on immunotoxicology evaluation; adopting a new experiment model of replacement, featuring high speed and reliability; introducing new techniques and new models in toxicological mechanism research; and establishing a new appraisal system to screen innovative drug and rapid and high precision methods for early security assessment, detection and measurement.     

Cache-Conscious Index Mechanism for Main-Memory Databases

Recent studies have addressed that the cache be havior is important in the design of main memory index structures. Cache-conscious indices such as the CSB^＋-tree are shown to outperform conventional main memory indices such as the AVL-tree and the T-tree. This paper proposes a cacheconscious version of the T-tree, CST-tree, defined according to the cache-conscious definition. To separate the keys within a node into two parts, the CST-tree can gain higher cache hit ratio.     

文化双调:作为记忆和图式的狂欢--从大众传播学看巴赫金的文化思想、方法及其意义

巴赫金的文化思想从20世纪60年代起在西方的文化研究中独树一帜，引人注目，既有系统而深刻的认识论背景，又有诸多方法论上的创新。这突出地表现在他的文化传播论述的两个大方面：从个体行为探究民间社会集体记忆与文化传承的关系；从知识建构的角度勾勒民间文化的形态图式及其历史变化过程。通过对巴赫金问题意识的讨论，本文还试图引出有较普遍意义的、能启发我们反思当代文化研究的一些问题。     

屏风村龙灯文化变迁中的国家与社会

国家与社会之间的关系是一个永恒的话题。一个小山村龙灯文化的消失过程 ,反映了国家与民间社会在集体记忆方面分歧、糅合、分离、混杂的历史互动关系的过程。屏风村龙灯文化所代表的民间社会在与国家的互动中 ,被迫放弃了记忆的基础之后 ,处于全能国家时代之后的一种混乱的记忆状态。如果这种现状无法改变 ,民间文化的重构将出现失序与混乱     

Sobolev方程Fourier拟谱方法的长时间稳定性和收敛性

考虑一维Sobolev方程的大时间问题, 构造了它的半离散和全离散拟谱逼近, 获得了时间区间0≤t<∞上一致最优阶的误差估计.     

英语科技文体的语言特征

从词法和语法的角度出发，分析了探讨了科技英语词汇、被动语态、名词化倾向、非限定性动词以及长句的应用等语言特点，总结出科技英语文体的一般特征。