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英语结构语言学及其现实意义 被引量:2
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作者 李玉萍 毕凤春 《沈阳农业大学学报(社会科学版)》 2005年第4期494-496,共3页
结构主义是20世纪语言学的主要理论,它由三个主要的学派组成:布拉格学派、哥本哈根和美国学派。结构语法是在美国描写语言学的基础上发展起来的,是美国语言学发展只上的一个重要时期,它们二者有着密不可分的关系。对中国人了解和掌握英... 结构主义是20世纪语言学的主要理论,它由三个主要的学派组成:布拉格学派、哥本哈根和美国学派。结构语法是在美国描写语言学的基础上发展起来的,是美国语言学发展只上的一个重要时期,它们二者有着密不可分的关系。对中国人了解和掌握英语结构和学习英语有一定现实意义。 展开更多
关键词 结构主度 结构语法 美国语言学
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Study on Adaptive Shape Optimization
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作者 邹文胜 左正兴 +1 位作者 范志刚 张儒华 《Journal of Beijing Institute of Technology》 EI CAS 1998年第2期154-160,共7页
Aim To introduce a new method of adaptive shape optimization (ASOP) based on three-dimensional structure boundary strength and optimize an engine bearing cap with the method. Methods Using the normal substance's p... Aim To introduce a new method of adaptive shape optimization (ASOP) based on three-dimensional structure boundary strength and optimize an engine bearing cap with the method. Methods Using the normal substance's property of thermal expansion and cooling shrinkage,the load which is proportional to the difference between the nodes' stress and their respective objective stress were applied to the corresponding variable nodes on the boundary.The thermal load made the nodes whose stress is greater than their objective stress expand along the boundary's normal direction and the nodes whose stress is less than objec- tive stress shrink in the opposite direction , This process would repeat until the stress on the boundary nodes was converge to the objective stress. Results The satisfied results have been obtained when optimizing an engine bearing cap.The mass of the bearing cap is reduced to 55 percent of the total. Conclusion ASOP is an efficient,practical and reliable method which is suitable for optimizing the shape of the continuous structures. 展开更多
关键词 adaptive shape optimization structure strength bearing cap
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Application of PCA and HCA to the Structure-Activity Relationship Study of Fluoroquinolones 被引量:2
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作者 李小红 张现周 +2 位作者 程新路 杨向东 朱遵略 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2006年第2期143-148,共6页
Density functional theory (DFT) was used to calculate molecular descriptors (properties) for 12 fluoro-quinolone with anti-S.pneumoniae activity. Principal component analysis (PCA) and hierarchical cluster analy... Density functional theory (DFT) was used to calculate molecular descriptors (properties) for 12 fluoro-quinolone with anti-S.pneumoniae activity. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were employed to reduce dimensionality and investigate in which variables should be more effective for classifying fluoroquinolones according to their degree of an-S.pneumoniae activity. The PCA results showed that the variables ELUMO, Q3, Q5, QA, logP, MR, VOL and △EHL of these compounds were responsible for the anti-S.pneumoniae activity. The HCA results were similar to those obtained with PCA.The methodologies of PCA and HCA provide a reliable rule for classifying new fluoroquinolones with antiS.pneumoniae activity. By using the chemometric results, 6 synthetic compounds were analyzed through the PCA and HCA and two of them are proposed as active molecules with anti-S.pneumoniae, which is consistent with the results of clinic experiments. 展开更多
关键词 Structure-activity relationship Density functional theory Principal component analysis Hierarchical cluster analysis
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Influence of expanded polystyrene size on deformation characteristics of light weight soil 被引量:15
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作者 侯天顺 《Journal of Central South University》 SCIE EI CAS 2012年第11期3320-3328,共9页
Deformation characteristics of light weight soil with different EPS (expanded polystyrene) sizes were investigated by consolidation tests.The results show that the confined stress-strain relation curve is in S shape,w... Deformation characteristics of light weight soil with different EPS (expanded polystyrene) sizes were investigated by consolidation tests.The results show that the confined stress-strain relation curve is in S shape,which has a good homologous relation with e-p curve and e-lgp curve,and three types of curves reflect obvious structural characteristics of light weight soil.When cement mixed ratio and EPS volume ratio are the same for different specimens,structural strength decreases with the increase of EPS size,but compressibility indexes basically keep unchanged within the structural strength.The settlement of light weight soil can be divided into instantaneous settlement and primary consolidation settlement.It has no obvious rheology property,and 90% of total consolidation deformation can be finished in 1 min.Settlement-time relation of light weight soil can be predicted by the hyperbolic model.S-lgt curve of light weight soil is not in anti-S shape.It is proved that there is no secondary consolidation section,so consolidation coefficient cannot be obtained by time logarithm method.Structural strength and unit price decrease with the increase of EPS size,but the reducing rate of the structural strength is lower than that of the unit price,so the cost of mixed soil can be reduced by increasing the EPS size.The EPS beads with 3-5 mm in diameter are suggested to be used in the construction process,and the prescription of mixed soil can be optimized. 展开更多
关键词 light weight soil expanded polystyrene (EPS) size effect one-dimensional consolidation theory compressibility index structural strength consolidation test
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Motivating Teachers 被引量:3
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作者 Daniela Martinek 《Sociology Study》 2012年第6期445-457,共13页
Teachers can motivate their pupils by fostering autonomous learning or---especially if they feel under pressure themselves--teachers can hamper the motivation of their students by being controlling. The purpose of thi... Teachers can motivate their pupils by fostering autonomous learning or---especially if they feel under pressure themselves--teachers can hamper the motivation of their students by being controlling. The purpose of this study with 488 secondary school teachers from Austria was to examine the satisfaction of teachers' needs for autonomy, competence and relatedness and meaningful relations to perceived job-related pressure and self-efficacy, to gain an increased insight in autonomy supportive contexts. The results point out that there are various sources for pressure in the teaching profession and structural equation modeling revealing a reciprocal relation between the satisfaction of the need for autonomy and pressure in teaching, as well as between the satisfaction of the need for competence and self-efficacy. In addition perceived pressure had a negative impact on teachers' self-efficacy and self-efficacy in turn influenced the satisfaction of the need for autonomy. In summary, considering basic psychological needs satisfaction of teachers seems relevant to create autonomy supportive environments for pupils and teachers in schools. 展开更多
关键词 Basic psychological needs PRESSURE SELF-EFFICACY
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Design of steel box girder for Taizhou Yangtze River Highway Bridge
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作者 Ding Lei Shan Hongwei Zhou Qing Zheng Benhui 《Engineering Sciences》 EI 2011年第2期57-63,共7页
Taizhou Yangtze River Highway Bridge is the first three-pylon two-span suspension bridge in China. The main girder adopts flat steamline steel closed box girder which has well wind-resistant capability and is technica... Taizhou Yangtze River Highway Bridge is the first three-pylon two-span suspension bridge in China. The main girder adopts flat steamline steel closed box girder which has well wind-resistant capability and is technically mature besides beautiful appearance. Straight web plates of the steel box girder in longitudinal direction are proposed in order to ensure the integrity of the steel box girder, and to keep the stress of the steel box girder continuous in the middle pylon, as well as to reduce the gradient of the middle pylon columns. The cross section of the box girder has one box with three cells. Solid-web diaphragm plate with good integrity and high torsional stiffness is adopted. The lifting lugs are utilized in the anchors of suspender cable. In this paper, selection of the cross section of the steel box girder, the general structure design, local structure design and main structure calculation results of Taizhou Yangtze River Bridge are introduced emphatically. 展开更多
关键词 Taizhou Yangtze River Highway Bridge three-pylon suspension bridge steel box girder DESIGN
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