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The separation of variables method was successfully used to resolve the spherically symmetric dynamic thermoelastic problem for a spherically isotropic elastic hollow sphere. Use of the integral transform can be avoided by means of this method, which is also appropriate for an arbitrary thickness hollow sphere subjected to arbitrary thermal and mechanical loads. Numerical results are presented to show the dynamic stress responses in the uniformly heated hollow spheres. 相似文献
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The separation of variables method was successfully, used to resolve the spherically symmetric dynamic thermoelastic problem
for a spherically isotropic elastic hollow sphere. Use of the integral transform can be avoided by means of this method, which
is also appropriate for an arbitrary thickness hollow sphere subjected to arbitrary thermal and mechanical loads. Numerical
results are presented to show the dynamic stress responses in the uniformly heated hollow spheres.
Project supported by the National Natural Science Foundation of China (Nos. 10172075, 10002016) 相似文献
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INTRODUCTION Recently, more and more investigations have been conducted on multilayer piezoelectric media. Kharouf and Heyliger (1994) and Heyliger and Ra- mirez (2000) dealt with the free vibration problems of laminated piezoelectric cylinders and discs, respec- tively. Chen (2000) considered the free vibration of (multilayer) nonhomogeneous piezoceramic hollow spheres by employing a separation formulation for displacements. Chen (2001) developed a state-space method for free vibration … 相似文献
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刘晓青 《陕西理工学院学报(社会科学版)》2000,(3)
利用电多极子电荷密度的δ函数表示式 ,导出了接地导体球附近任意电偶极子和电四极子的电象一般公式 .并指出高阶电多极子电象的求解方法 . 相似文献
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An analytical solution is obtained for a rotating multiferroic composite hollow cylinder made of radially polarized piezoelectric and piezomagnetic materials. Both the number of layers and the stacking sequence of the composite cylinder can be arbitrary. General mechanical, electric and magnetic boundary conditions can be applied at both the inner and outer cylindrical surfaces. The state space method is employed so that only a 2×2 matrix is involved in the whole solving procedure. In the numerical experiments, the distributions of elastic, electric as well as magnetic fields in an internally pressurized rotating BaTiO3/CoFe2O4 composite hollow cylinder subjected to different boundary conditions are presented graphically. The results clearly show that the stress fields in a multiferroic composite cylinder are controllable. 相似文献
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Yang Jihua 《大连大学学报》1992,(4)
本文对开孔(水工)结构进行了结构动力特性和规则波作用下结构动力响应的模型试验,并用有限元法计算了结构自振特性,分析了3种水位、不同波高、周期情况下结构的动力特性和结构的动力响应. 相似文献
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Gloria D. Eldridge Joseph J. Pear Laine J. Torgrud Blair H. Evers 《Learning & behavior》1988,16(3):277-284
Three pigeons were exposed to fixed-time (FT) 15 sec, fixed-interval (FI) 15 sec for performing an arbitrary response, a reversal back to FT 15 sec, and then extinction (no reinforcement). During each phase, a computer-controlled tracking system continuously recorded the position of the bird’s head as it moved freely in the experimental chamber. During the first exposure to FT 15 sec, all 3 birds developed a pattern of feeder-wall-directed behavior with occasional circular excursions from the feeder immediately following reinforcement. During FI 15 sec, all birds performed the arbitrary operant, which consisted of contacting a virtual target sphere near the rear of the chamber, and did not engage in feeder-wall-directed behavior. During the reversal back to FT 15 sec, the birds developed a behavior sequence consisting of moving in the direction of the target sphere after reinforcement, followed by feeder-wall-directed behavior prior to the next reinforcement. During extinction, either moves toward the target sphere or wall-directed behavior occurred separately, interspersed with reappearance of the two as a sequence, followed by cessation of both members of the behavior sequence. These findings indicate that prior reinforcement of an arbitrary response can affect the location and form of superstitious behavior that develops near the beginning of the interreinforcement interval, but that other factors (e.g., immediacy of reinforcement) affect the location and form of the behavior near the end of the interval. The findings can be interpreted in the context of superstitious chaining. 相似文献
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李应乐 《咸阳师范学院学报》2005,20(2):16-19
研究了高速运动的介质目标对任意频率电磁渡的散射,系统地导出了坐标系相对沿着z轴运动时的坐标变换关系、波矢量变换关系以及电磁场的变换关系。首次给出了两个相对作高速匀速运动的球坐标系中的三角函数的变换关系以及矢量的球坐标分量的变换关系,为研究高速运动目标的电磁波散射奠定了理论基础。利用Mie理论。详细地研究了高速运动介质球的散射特性,得到了散射截面的解析表达式并对其进行了仿真和讨论。结果表明:介质球做高速运动时,前向散射大于后向散射,和其它的观察方位相比,入射波频率对散射的影响不大,多普勒效应起主要作用,目标表面上的二次辐射源以电偶极辐射为主。 相似文献
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基于物联网、高速宽带网、云计算和大数据等新信息技术基础上的智慧城市建设已成为现代化发展的新趋势,随着智慧城市中网络的发展和普及,以网络为公共空间和互动平台,以网民为主体,网络公共领域及其网络舆论已经影响到我国政治和社会生活的稳定。基于哈贝马斯的公共领域理论,在研究信息分享(弱关系)和情感分享(强关系)基础上网络公共领域的内在动力机制,提出了网络公共领域建构的过程:结构性诱因、结构性紧张、网络互动、一般性信念(网络共意)、触发因素、行动动员和社会控制;并提出引导网络公共领域的对策。 相似文献
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弃权票作为法律规定的一种选择,其价值的实现尚不明确。通过对弃权票的分析,发现其具有提升人大代表的权利主体意识、促进人大代表权利实现,监督国家权力和推进国家职能变革等宪政价值,只要合理规避弃权票的不当使用所造成的影响人民意志的表达及降低人大会议工作的效率等危害,充分发挥弃权票在使用过程中的功能价值,会不断促进人大代表权利的正确行使,推动国家民主法治建设的发展和完善。 相似文献
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Robert Asen 《Quarterly Journal of Speech》2017,103(4):329-349
This essay considers the challenges that neoliberalism raises for conceptual models and practices of a multiple public sphere. Engaging difference and attending to inequality, a multiple public sphere facilitates the circulation of a dynamic public good that may articulate mutual standing and relationships among people to enable the construction of a collective “we” for coordinated action. Weakening relationships among people and devaluing coordinated action, neoliberalism envisions a public of atomistic individuals who compete with one another for comparative advantage. Flattening difference and obscuring inequality, a neoliberal public presumes a universal subject that obscures its own particularity and discounts the uneven burdens faced by those who cannot seamlessly identify with its mode of subjectivity. Further, for a neoliberal public, inequality serves as the condition and end of competition. Resistance to neoliberalism may arise in the networked locals of a multiple public sphere, as advocates reclaim connections that neoliberalism seeks to deny. 相似文献
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何新是当代中国著名学者,其学术涉及面广。开展何新学术研究与批判有利于推动多领域学术进步;开展研究与批判要注意准确全面把握何新学术内容,运用正确的立场、观点和方法,注意区分何新学术的多层次性,并注意在其学术发展的动态过程中加以考察。 相似文献
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本文从绕线式异步电动机的数学模型出发，推导出在任意同步旋转坐标系下电机的动态仿真框图，一改常规交流传动计算机仿真方法，应用Ｓｉｍｕｌｉｎｋ仿真软件包建立绕线式异步电动机的数学模型，并对其进行改造以方便串级调速的实现．本模型能设定几乎所用电机内部物理量的数值，可以方便地用于电机及其控制系统的稳态及其动态性能分析与研究．最后以实际的ＪＺＲ１１—６型绕线式三相异步电动机为例进行验证，证明了仿真模型的有效性和可行性． 相似文献
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为检验在役双曲拱桥的承载能力与动力特性,对某净跨为36 m空腹式双曲拱桥进行了静载试验、动载试验及空间有限元分析。测试结构的静态应变、动态应变、挠度、自振频率、振型及加速度等结构反应,计算得出冲击系数。将实测结果与有限元结果进行对比分析,结果表明:应变校验系数为0.5~0.9,结构具有较好承载力。实测的各阶频率及相应振型与有限元计算结果比较吻合,桥梁整体竖向刚度较好。 相似文献
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陈立群 《商丘师范学院学报》1996,(Z4)
给出了一般初值条件下无阻尼自由度振系对简谐激励的响应公式，作为特例讨论了无阻尼动力吸振器，结果表明无阻尼动力吸报器并不能完全消除主系统的振动。 相似文献
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张靖仪 《湖南师范大学教育科学学报》1997,(2)
对应于静止带电球对称分布流体球，本文绘出了一种获得Einstein－Maxwell方程精确解的方法，得出了两个新的精确解．并且比较详尽地讨论了它们的物理性质． 相似文献