中国学习者英语书面语多词动词特征研究--基于语料库的方法

根据Biber等人(1999)提出的研究框架,对中国学习者使用英语中频率最高的141个多词动词的情况进行调查分析。分别从中国英语学习者语料库和英国国家语料库的采样中提取出多词动词,并采取中介语对比研究的方法对两组数据进行对比。研究结果表明,两组所得多词动词分布模式存在显著性差异。与英语母语者相比,中国学习者英语多词动词的使用总体偏低,并且倾向于过多使用语法结构相对简单的多词动词。     

水轮发电机组计算机监控实时仿真系统的实现

提出了一种水轮发电机组计算机监控实时仿真系统构建方案。通过对水轮发电机组及其辅助设备进行数字仿真,再结合监控层的应用软件及硬件,构成混合仿真系统,实现了计算机监控系统对水轮发电机组一系列动态过程监控的实时仿真。     

Estimation of mean and variance of stigmatized quantitative variable using distinct units in randomized response sampling

Received: April 6, 1998; revised version: July 12, 1999     

Estimating numbers of infectious units from serial dilution assays

Summary.  The paper concerns the design and analysis of serial dilution assays to estimate the infectivity of a sample of tissue when it is assumed that the sample contains a finite number of indivisible infectious units such that a subsample will be infectious if it contains one or more of these units. The aim of the study is to estimate the number of infectious units in the original sample. The standard approach to the analysis of data from such a study is based on the assumption of independence of aliquots both at the same dilution level and at different dilution levels, so that the numbers of infectious units in the aliquots follow independent Poisson distributions. An alternative approach is based on calculation of the expected value of the total number of samples tested that are not infectious. We derive the likelihood for the data on the basis of the discrete number of infectious units, enabling calculation of the maximum likelihood estimate and likelihood-based confidence intervals. We use the exact probabilities that are obtained to compare the maximum likelihood estimate with those given by the other methods in terms of bias and standard error and to compare the coverage of the confidence intervals. We show that the methods have very similar properties and conclude that for practical use the method that is based on the Poisson assumption is to be recommended, since it can be implemented by using standard statistical software. Finally we consider the design of serial dilution assays, concluding that it is important that neither the dilution factor nor the number of samples that remain untested should be too large.     

换热器中熵产数和■效率的计算与分析

本文建立了换热器的熵产数、单位有效度的熵产数、效率与其各自影响因素间的函数关系。对其变化规律和形成这些规律的原因进行了全面系统的研究。研究结果有较广泛的适用性。     

简论全国重点文物保护单位在旅游业发展中的作用和地位

论述了全国重点文物保护单位在我国旅游业发展中的重要作用和显著地位，分析了其存在的问题和矛盾，并就进一步做好全国重点文物保护单位的保护、管理和合理利用工作，把旅游业培育成国民经济的重要产业等提出对策和建议。     

风险投资法律组织形态分析

本文在概述风险投资基本运作的基础上 ,着重对风险投资法律组织形式的制度选择的有效性予以分析 ,从而说明有限合伙制是风险投资法律组织形态的首选形式 ,并对我国风险投资法律组织形式提出相应的立法建议     

Estimation of parameters of 1-out-of-2:g repairable system

Moment estimators of l-out-of-2:G repairable system are supplied under four sampling schemes assuming that the failure and repair time distribution of the units are exponential with unknown parameters λ, μ respectively. Information metrices of the estimators are supplied. Also it is shown that the estimators are asymptotically normally distributed in every sampling scheme.     

Interpenetrating subsampling of unequal samples and the estimator with distinct units

In this article Pathak's (1964) results on estimation of mean and variance for k-equal subsamples and Rao's (1975) result on the expectation of the reciprocal of the number of distinct units obtained from two unequal subsamples , for interpenetrating subsampling scheme, have been extended to the case of k-unequal subsamples.     

认知语言学视角下多词单位的二语教学研究

传统语言学视角下的多词单位缺乏理据性,教学通常是难题,认知语言学为其提供了新的视角。国内外学者已做过认知语言学和二语教学相结合的多词单位实证研究。主要依据原型理论、概念隐喻、词源理据、意象及意象图式等认知原理具体介绍四项实证研究,并从研究使用的教学内容、教学方法和测试方法等方面进行评价。根据其研究不足,提出对未来研究的展望,以期对外语语言工作者、外语教师和研究者在多词单位的实证研究和教学方面有所启示。