普通英语与专门用途英语的教学整合探索——以飞行基础英语与民航英语为例

普通英语与专门用途英语是大学英语教学的两个阶段。如何实现两者的顺利过渡是提高专门用途英语教学的关键。本文首先探讨了普通英语与专门用途英语的异同,并以飞行基础英语和民航英语为例,以两者的关系为基础,分析了从教学目标、教材、师资三方面将普通英语与专门用途英语进行教学整合的措施,以促进专门用途英语教学质量的提高。     

SiC颗粒强韧化MoSi2复合材料研究

本文通过对热压合成制备的SiC MoSi2 复合材料显微组织及其断口形貌分析 ,结合硬度、抗弯强度、断裂韧度等力学性能和孔隙率、晶粒度的测试 ,初步探讨了SiC颗粒强韧化MoSi2 复合材料的效果和机制。     

Multiple-model estimation with variable structure. III. Model-groupswitching algorithm

A general multiple-model (MM) estimator with a variable structure (VSMM), railed model-group switching (MGS) algorithm, is presented. It assumes that the total set of models can be covered by a number of model groups, each representing a cluster of closely related system behavior patterns or structures, and a particular group is running at any given time determined by a hard decision. This algorithm is the first VSMM estimator that is generally applicable to a large class of problems with hybrid (continuous and discrete) uncertainties. It is also easily implementable. It is illustrated, via a simple fault detection and identification example, that the MGS algorithm provides a substantial reduction in computation while having identical performance with the fixed-structure Interacting Multiple-Model (FSIMM) estimator     

Accumulation of tumor suppressor p53 in rat muscle after a space flight.

Tumor suppressor p53 functions as a cell cycle checkpoint under stressful conditions. Early studies have shown that genotoxic stress activates p53 pathway. Recently, many kinds of non-genotoxic stress such as heat shock, cold shock, and low pH also have been found to activate p53 pathway. The effects on living organism remains to be explored. Here, we show that an 18-day space flight induced a 3.6 fold accumulation of p53 in rat skeletal muscle. This results suggests that the p53 pathway plays a role in safeguarding genomic stability against the stressful space environments and supports our previous observation of p53 accumulation in rat skin after a space flight.     

Inertial Flight Mode and Semiconductor Segregation Patterns

In this work, a 2D time-dependent Bridgman model has been used to analyze the impact of the inertial flight mode on the resulting crystal dopant homogeneity. To be as near as possible to the experimentalists, the discussion has been based on the computed solid dopant segregation. Excepting a few cases at the lowest value of gravity, 1 g, the model is amazingly sensitive to the orbital characteristics. In effect, alternated dopant structures appear recorded in the solid phases as clear fingerprints of the nonlinear vibroconvective flow effects acting along the simulated growth processes. Thus, to improve crystal homogeneity, some strategies should be introduced to eliminate also these pernicious effects.     

我国房产税存在的问题及对策

本文重点分析了现行房产税存在的主要问题 :征税范围不全面、税基窄 ;内外企业分设两套税法、税制不统一 ;计税依据不尽合理等。笔者认为应借鉴国际经验 ,据中国国情 ,适时调整税收政策 ,坚持税收“中性”原则 ,统一税法 ,扩大征税范围、拓宽税基、改进计税依据、合理设计税率     

经济可持续增长与产业结构的税收政策关联性分析

经济可持续增长除资本、技术、资源、人才因素外,还与产业结构的布局密切相关。在阐述我国产业结构的现状、三次产业之间的比例不合理、三次产业内部结构不合理,及我国三次产业的税收政策后,调整三次产业结构,提出了促进经济可持续增长,完善三次产业的税收政策取向。     

基于面向对象PETRI网的移动式Agent系统

 为了简化移动式Agent 的设计和实现,描述了以OOPN 为建模语言,建立移动式Agent 系统的基本原理。该系统提供了可视化系统建模、死锁检测和实际的系统运作功能。首先介绍OOPN 的基本概念和Agent 编程工具Aglets,在此基础上介绍如何通过OOPN 建模来生成移动式Agent 系统的具体实现机制,包括Agent 的远程创建和动态部署。最后通过生产者—消费者实例来说明整个系统的执行过程。     

Evaluation of estimation algorithms part I: incomprehensive measures of performance

Practical metrics for performance evaluation of estimation algorithms are discussed. A variety of metrics useful for evaluating various aspects of the performance of an estimation algorithm is introduced and justified. They can be classified in two different ways: 1) absolute error measures (without a reference), relative error measures (with a reference), or frequency counts (of some events), and 2) optimistic (i.e., how good the performance is), pessimistic (i.e., how bad the performance is), or balanced (neither optimistic nor pessimistic). Pros and cons of these metrics and the widely-used RMS error are explained. The paper advocates replacing the RMS error in many cases by a measure called average Euclidean error     

MoSi2及其复合材料的研究进展

介绍了MoSi2的性能特点，阐述了它的应用领域，并从合金化和复合化等方面综述了对MoSi2及其复合材料进行强韧化的途径，同时还展望了其发展趋势和应用前景。