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101.
对事物进行比较的能力构成了人类最基本的认知能力,语言中的各种比较结构.正是人们对事物异同意识的外化形式,比较结构就是这种外化形式的基本表现形式.它是世界上所有语言共有的语法现象。通过汉英比较结构的对比。可以发现汉英比较句具有深层次的共性特征。  相似文献   
102.
写作是全国大学英语四、六级统考很重要的组成部分,它客观地反映出考生的英语语言的综合应用能力,有助于教师了解和评价学生的英语真实水平和语言素养。文章对近一、二年大学英语四、六级作文34篇样卷(RANGE—FINDERS,6RSH2)反映出的考生在词语搭配、语义知识、句法结构和文体程式化方面存在的问题进行了量化研究,并探讨大学英语写作教学上亟待解决的一些问题。  相似文献   
103.
The space sheet for a solar array structure is large in dimension, and flexible to induce complex distortion. It is difficult to measure the distortion. A large-scale flexible test prototype system is built for sheet structure vibration monitoring based on the vibration information of the solar array in space. The system provides an intelligent test method for flexible space structure with embedded sensors and non-visualization reinstruction. Multiple fiber Bragg grating (FBG) sensors are packaged and embedded into the structure with spatial division multiplexing (SDM) and wavelength division multiplexing (WDM). The sensor interrogator distinguishes wavelength shifts that can be turned into curvature of the curve. The structure shape is reconstructed based on the curvature information and the arc-length, and then displayed. The experiment shows that the system has a high FBG sensitivity. The reconstruction algorithm is fast with high precision. The system has great potential for use in health monitoring of the space sheet structure.  相似文献   
104.
文章提出基于神经网络重要抽样法的结构可靠度评估方法,该方法通过训练神经网络,建立随机变量与结构响应之间的非线性映射关系,模拟结构极限状态方程,采用优化算法计算设计点.在重要抽样法中利用训练好的神经网络代替有限元求解器进行数值计算.结果表明,所训练的神经网络能够有效地模拟真实的结构极限状态方程,结构失效概率计算结果具有很高的精度,调用有限元分析的次数显著减少,有效地提高了计算效率.  相似文献   
105.
Wind loading is a dominant factor for design of a cable-membrane structure. Three orthogonal turbulent components, including the longitudinal, lateral and vertical wind velocities, should be taken into account for the wind loads. In this study, a stochastic 3D coupling wind field model is derived by the spectral representation theory. The coherence functions of the three orthogonal turbulent components are considered in this model. Then the model is applied to generate the three correlated wind turbulent components. After that, formulae are proposed to transform the velocities into wind loads, and to introduce the modified wind pressure force. Finally, a wind-induced time-history response analysis is conducted for a 3D cable-membrane structure. Analytical results indicate that responses induced by the proposed wind load model are 10%-25% larger than those by the con- ventional uncorrelated model, and that the responses are not quite influenced by the modified wind pressure force. Therefore, we concluded that, in the time-history response analysis, the coherences of the three orthogonal turbulent components are necessary for a 3D cable-membrane structure, but the modified wind pressure force can be ignored.  相似文献   
106.
王春凤 《科教文汇》2013,(36):139-139,142
三角求值、化简、证明是三角的主要题型,在所有的三角问题中,以“变”为主线,通过一系列的“变角”、“变次”、“变次”、“变结构”等方法枣解决问题。  相似文献   
107.
In this phenomenological study, the authors investigated the experiences of African American counselors‐in‐training, with roots in the Black church, as they navigated their faith and professional responsibilities to provide affirming services to lesbian, gay, and bisexual clients. Findings suggest attitudes toward lesbian, gay, and bisexual clients are intertwined with faith, race, and community allegiance.  相似文献   
108.
Opportunities to Learn in the Budapest Mathematics Classroom   总被引:1,自引:0,他引:1  
This paper examines the nature of the problems posed, the processes by which their solutions were made public, their structural contribution to a lesson and the opportunities they offered for the learning of mathematics in Budapest, Hungary. The problems were derived from observations, the processes of which were informed by various comparative studies, of 94 mathematics lessons in the 10–14 age range. Problems, the analysis and categorisation of which were informed by the literature, tended to fall into two categories – single response with high levels of cognitive demand and multiple response with high levels of cognitive demand. Structurally lessons fell into a well practised pattern of classroom behaviour. They began with a public review of homework, comprising two or three multiple response problems which were solved collaboratively. This was followed by a warm-up period involving the oral setting and mental solving of a few single response problems. Lastly, the main body of the lesson involved several cycles in which a multiple response problem was posed, attempted individually before solutions were shared publicly. Lessons ended with homework being set. The discussion of the findings is framed by Hungary's variable performance on recent international tests of mathematical attainment.  相似文献   
109.
关于我国研究生教育层次结构优化的若干思考   总被引:5,自引:0,他引:5  
文章以阐述研究生教育层次结构优化的标准为基础,对我国研究生教育层次结构的发展现状与问题进行了定量分析,并指出了优化我国研究生教育层次结构全过程中必须注意的问题,提出从总体上控制一个合理的比例关系、实行研究生培养单位的任务分工、实施研究生教育形式的多样化、分别不同科类不同专业调整研究生教育层次等是优化我国研究生教育层次结构的基本对策。  相似文献   
110.
To find out the detailed characteristics of the coherent structures and associated particle dispersion in free shear flow, large eddy simulation method was adopted to investigate a two-dimensional particle-laden wake flow. The well-known Sub-grid Scale mode introduced by Smagorinsky was employed to simulate the gas flow field and Lagrangian approach was used to trace the particles. The results showed that the typical large-scale vortex structures exhibit a stable counter rotating arrangement of opposite sign, and alternately form from the near wall region, shed and move towards the downstream positions of the wake with the development of the flow. For particle dispersion, the Stokes number of particles is a key parameter. At the Stokes numbers of 1.4 and 3.8 the particles concentrate highly in the outer boundary regions. While the particles congregate densely in the vortex core regions at the Stokes number of 0.15, and the particles at Stokes number of 15 assemble in the vortex braid regions and the rib regions between the adjoining vortex structures.  相似文献   
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