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C. Wolf 《Astronomische Nachrichten》1988,309(3):173-175
In two theories involving continuous creation higher order curvature terms are added to the field equations. At high gravitational curvatures the creation of matter depends critically on these extra terms. 相似文献
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D. Lorenz-Petzold 《Journal of Astrophysics and Astronomy》1985,6(3):137-144
We derive some new exact 7-dimensional cosmological solutions |R⊗ I ⊗N, whereN = I, II, VI0, VII0, VIII and IX are the various 3-dimensional Bianchi models. The solutions given are higher-dimensional generalizations of
the mixmaster cosmologies. There is a strong influence of the extra spacesN, which results in a fundamental change of the 3-dimensional cosmology. 相似文献
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注册测绘师制度的推行,对我国测绘行业人员提出了更高要求,为了适应新形势下国家对测绘人才培养的需求,高职工程测量专业进行教学改革迫在眉睫。从注册测绘师所要求的知识结构和专业能力入手分析,探讨了工程测量专业课程体系、实践教学、师资队伍、教学方法与手段、学生考核评价方式以及校企合作方式的教学改革,为高职工程测量人才培养提供了保障。 相似文献
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波浪水槽中非线性浅水波传播特性与模拟 总被引:2,自引:0,他引:2
通过建立解析解、进行数值模拟和物理实验,研究了波浪水槽中非线性浅水波浪传播特性,给出了数值模拟中对应造波板做正弦运动的二阶入射边界条件。数值模拟采用高阶Boussinesq方程。实验结果、数值结果和解析解进行对比,并讨论了解析解的适用范围、高次谐波的产生及三波相互作用问题。 相似文献
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Jamison Miller 《The Professional geographer》2018,70(1):165-173
Emerging less than a decade ago, the term EDUPUNK sought to encapsulate the nascent rebellion against the corporatism and neoliberal ideology permeating digital aspects of higher education. A loose association of academic technologists with interests in net neutrality, open source software, hacktivism, and so on, the EDUPUNK movement has also been informing the adoption of various open practices in higher education, including open educational resources (OER). Intriguingly, university administrators and policymakers—attracted by aspects such as increased access and lower costs for students—are taking notice. In this article, I focus on developments from across the state of Virginia to introduce a critical praxis landscape from within higher education. Thus, I showcase some of the opportunities for critical technology praxis within the neoliberal(izing) university. 相似文献
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An improvement is first suggested to the modal pushover analysis (MPA) procedure for bridges initially proposed by the writers (Earthquake Engng Struct. Dyn. 2006; 35 (11):1269–1293), the key idea being that the deformed shape of the structure responding inelastically to the considered earthquake level is used in lieu of the elastic mode shape. The proposed MPA procedure is then verified by applying it to two actual bridges. The first structure is the Krystallopigi bridge, a 638 m‐long multi‐span bridge, with significant curvature in plan, unequal pier heights, and different types of pier‐to‐deck connections. The second structure is a 100 m‐long three‐span overpass bridge, typical in modern motorway construction in Europe, which, although ostensibly a regular structure, is found to exhibit a rather unsymmetric response in the transverse direction, mainly due to torsional irregularity. The bridges are assessed using response spectrum, ‘standard’ pushover (SPA), and MPA, and finally using non‐linear response history analysis (NL‐RHA) for a number of spectrum‐compatible motions. The MPA provided a good estimate of the maximum inelastic deck displacement for several earthquake intensities. The SPA on the other hand could not predict well the inelastic deck displacements of bridges wherever the contribution of the first mode to the response of the bridge was relatively low. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献