二元结构下的城乡消费差异分析及对策

二元结构是指发展中国家社会中政治、经济、文化、教育等多方面结构的断层和分化。由于计划经济体制的影响，我国的城乡二元结构比一般发展中国家更为突出。本文将城乡消费差异纳入二元经济结构中加以考察，并运用垄断厂商逐利行为导致的供给歧视理论对城乡消费差异进行了数理经济分析，发现城乡消费差异不仅是因为二元结构的体制原因，还有垄断厂商供应歧视的经济动因。因此，要建设城乡互动的和谐社会，除了要消除二元结构的体制格局外，还要规范厂商行为、扩大农村商品流通、引导农民消费行为，也许这种规范和引导会成为最终消除城乡二元结构的重要政策选择。     

海带与裙带菜种群遗传结构的比较研究

用聚丙烯酰胺凝胶电泳对海带、裙带菜６种同工酶电泳所获得的遗传信息进行了分析、比较,通过裙带菜９种同工酶的电泳,对其丝状体（配子体）和叶状体（孢子体）基因表达的重叠性与特有性进行了研究,结果显示海带丝状体同工酶生化遗传结构中的各种指标均高于裙带菜丝状体,说明海带遗传多样性比裙带菜丰富,发现裙带菜丝状体的基因表达量除与叶状体重叠外,还有其特有性     

浅论图书馆知识组织的功能及形式

本认为知识组织充分体现了图书馆的基本职能,知识组织是图书馆在知识经济时代生存和发展的需要,并对图书馆的知识组织形式进行了评价。     

《搜神记》动结式述补结构研究

<搜神记>的口语色彩较浓,反映了当时生动活泼的用语状况,探讨<搜神记>中的语法现象对汉语史,尤其是中古汉语的研究有重要意义.本文首先确定了动结式述补结构的判定标准,然后对<搜神记>的动结式述补结构进行分类描写,最后指出书中的相似结构并加以区分.     

试论汉英比较句结构的共性

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。     

语义知识和文体知识同大学英语写作能力的正相关解读

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。     

Vibration shape testing of space sheet structure

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.     

基于神经网络重要抽样法的结构可靠度评估

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．     

3D wind-induced response analysis of a cable-membrane structure

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.     

“变”在三角函数中

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。