县（市）域城镇体系结构及其优化——以浙江省桐乡市为例

通过深入分析浙江桐乡市域城镇体系结构,认为桐乡市域城镇体系具有中心城市能级低,次级城镇缺失,城镇规模偏小,城镇体系发育不全,小城镇功能趋同、职能单一,城镇化水平不高且地域分布不均等特征,并据此提出了以构建城镇组团为重点,构筑城镇新体系;发展产业集群,提升产业层次,形成功能互补、特色鲜明的城镇职能结构,提高城镇化水平;完善城乡网络系统,形成以城镇组团为依托,发展轴线清晰的城镇体系空间格局等构想与建议。     

An Integrated Knowledge Framework to Characterize and Scaffold Size and Scale Cognition (FS2C)

Size and scale cognition is a critical ability associated with reasoning with concepts in different disciplines of science, technology, engineering, and mathematics. As such, researchers and educators have identified the need for young learners and their educators to become scale-literate. Informed by developmental psychology literature and recent findings in nanoscale science and engineering education, we propose an integrated knowledge framework for characterizing and scaffolding size and scale cognition called the FS2C framework. Five ad hoc assessment tasks were designed informed by the FS2C framework with the goal of identifying participants' understandings of size and scale. Findings identified participants' difficulties to discern different sizes of microscale and nanoscale objects and a low level of sophistication on identifying scale worlds among participants. Results also identified that as bigger the difference between the sizes of the objects is, the more difficult was for participants to identify how many times an object is bigger or smaller than another one. Similarly, participants showed difficulties to estimate approximate sizes of sub-macroscopic objects as well as a difficulty for participants to estimate the size of very large objects. Participants' accurate location of objects on a logarithmic scale was also challenging.     

基于尺寸设计变量的声场-结构耦合系统的敏度分析

本文应用有限元方法对声场-结构耦合系统进行数值模拟和灵敏度分析.通过在结构设计阶段数值方法的研究,对耦合系统基于尺寸设计变量的特征频率和特征向量的灵敏度进行了分析,并通过数值算例的结果表明了算法的正确性,可为耦合系统的声学性态优化设计提供理论和算法基础.     

企业收缩性资本运营的理论基础

企业收缩性资本运营除了一般的动因以外，还有深刻的理论基础。交易费用理论认为，一个企业的资产特定性越低，该企业就应进行适当的分立；新产权理论认为，企业资产互为独立时，分立是最优行为；信息技术影响论认为，当信息技术使得一些资产更具“柔性”而很少被有形资产“套牢”时，它将有助于资产所有权的分散；公司规模不相关理论认为。若中间品的交易效率超过劳动力的交易效率，公司规模和经营范围就会随个人专业化水平的提高和生产活动范围的减小而缩小；企业寿命周期理论认为，若一家公司超过了最优规模，可通过剥离来进行回归，若不进行更新，公司最终就会衰退以至消亡．     

Numerical evaluation of sample size effect on the stress-strain behavior of geotextile-reinforced sand

This paper studies the effect of sample size on the stress-strain behavior and strength characteristics of geotextile reinforced sand using the finite element numerical analysis. The effect of sample size was investigated by studying the effects of varying the number of geotextile layers, the confining pressure and the type of geotextile. Modeling was performed on samples with five different diameters： 38, 100, 200, 500 and 600 mm. The elastic-plastic Mohr-Coulomb model was used to simulate sand behavior. Results showed that small-sized samples show higher values of peak strength and higher axial strain at failure in comparison with large-sized samples. The size effect on the behavior of samples became further apparent when the number of geotextile layers was increased or the confining pressure was decreased. In addition, the results indicated that the magnitude of the size effect on the mechanical behavior of reinforced sand decreases with an increase in the sample size.     

边际收益递减规律与图书馆藏书发展

介绍了边际收益递减规律和“图书馆馆藏稳定状态”理论,并尝试利用边际收益递减规律解释馆藏规模理想状态存在的合理性以及藏书发展与图书馆服务之间的关系。     

AutoCAD在计算定位误差中的应用

阐述利用CAD软件来测定工件在夹具上的定位误差,用AUTOCAD绘图软件举例说明这种方法的使用过程,与传统的计算方法比较,这种计算方法更方便、更精确,也为工程上类似计算提供了一种思路．     

技术创新中的企业适度规模

本文探讨了企业的技术创新和企业规模的互动关系,从资金的投入强度和研究开发(R&D)人员的努力程度这两个技术创新成败决定性因素的角度论述了企业适度规模问题,得到技术创新中的适度企业规模范围.     

介绍一个物理化学实验--粒度分析

粒度分析又称为沉降分析是物理化学实验之一.主要方法有重力场下的沉降和超离心沉降,实验主要介绍超离心沉降法,其原理是基于固体颗粒的离心沉降和光透射原理来测定颗粒的粒度大小及分布,它以Stokes定律和lamber-Beel定律为基础,可采用恒速或变速测定方式.用计算机控制整个测试过程,具有快速、宽域、重复性好、操作简便等特点.     

Lysozyme refolding at high concentration by dilution andsize-exclusion chromatography

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