121 research outputs found

    Efficient Simulation Methods for Reinforced Concrete Columns with Encased Steel in High-rise Building Structures

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    型钢混凝土柱在建筑结构中往往是主要的承重构件之一,使用合适的数值模型分析其力学性能对高层结构抗震分析有重要的意义。本文综述了目前文献中已有的低含钢率恢复力模型相关研究,分析了其理论、计算流程和算法,并在通用有限元软件OpenSees中编程实现。本文详细推导了模型中基本参数的确定方法,并用于模拟实际高层建筑结构中的型钢混凝土柱。首先,本文用恢复力模型模拟了单根型钢混凝土柱的试验,通过对比验证了模型的精度,研究了其计算效率。其次,本文将恢复力模型用于理想32层高层结构中的单排型钢混凝土构件静、动力分析中。根据与纤维模型计算结果的对比,证明使用恢复力模型分析高层结构中的局部构件抗震性能时较传统的纤维...The steel reinforced concrete column plays an essential role in the structural analysis. Therefore, choosing a suitable simulation method for these components is of significant importance. In this background, the thesis reviews a resilience model for the reinforced concrete column with low ratios encased steel, studies the calibration method for the model parameters, designs the flowcharts of the ...学位:工学硕士院系专业:建筑与土木工程学院_结构工程学号:2532013115180

    Managerial Power, Abnormal Executive Compensation and Audit Opinion: Evidence from China

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    委托代理理论认为,对高管进行有效的薪酬激励是为了将高管利益与股东价值最大化相联系,从而缓解高管与股东间存在的代理冲突。但在我国资本市场上,却屡屡出现与行业平均水平偏离较大、和公司业绩表现并不紧密相关甚至“背道而驰”的上市公司高管薪酬状况。 一方面,现有研究表明上市公司高管薪酬情况会受高管拥有权力的影响,出现异常高管薪酬的公司内部治理机制可能存在一定的缺陷。当公司内部治理机制难以对管理层权力进行限制时,高管可能会利用自身在公司中拥有的权力,调节薪酬状况,而这破坏了股东与高管间有关高管薪酬激励契约的有效性,影响了股东利益最大化的实现。另一方面,现有研究也发现注册会计师基于审计风险的考虑,可能会通...According to Agency Theory, the purpose of incentives in top-level executive compensation is relating the interests of top executives with the interests of shareholders, alleviating the agency conflict between top executives and shareholders. However on China’s capital market, there exists some abnormal phenomena in which the executive compensation are deviated greatly from the industry averages o...学位:管理学硕士院系专业:管理学院_会计学学号:1752011115119

    Reconstruction of 3D Objects Utilizing the Frame Features

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    论文以交通视频检测为背景,系统地对由直线段与面等组成的框架特征下,双目立体视觉中的三维重建涉及到的各个环节进行了研究和讨论,提出了一些新的算法,并给出了一个的解决方案,同时实现了系统的核心功能。 本文工作的贡献主要包括以下三个方面: 1、关于轮廓提取算法:对现有常用的图像分割算法进行了总结,并在研究前人成果的基础上,提出了一种基于边界的轮廓提取算法。在室内场景和交通场景中进行了实验,取得了较好的效果。 2、关于目标物体分割算法:讨论了利用框架特征的目标物体表面分割算法,提出了一种基于立体信息的目标物体表面分割算法。通过实验,取得了预期的效果,证明了所提出算法的可靠性。对基于框架特征的三维...This thesis studies the reconstruction of 3D objects utilizing the frame features in the scope of Binocular Vision. A reasonable system scheme is proposed, and the kernel functions of the system is implemented and tested. Our experiment results show the feasibility of the proposed system. Our work chooses the Traffic Video Detection System as the research background. Some new algorithms for 3D ob...学位:工学硕士院系专业:信息科学与技术学院计算机科学系_计算机应用技术学号:20042802

    Seismic Response Sensitivity Analysis of Soil-Structure Interaction Systems

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    本文概述了基于直接微分法的非线性有限元动力响应对于模型材料参数、几何参数和地震不确定性参数的敏感性分析方法,介绍了基于力法、位移法和三场混合法等方法的有限单元直接微分法敏感性分析最新进展,并着重讲述了将直接微分法拓展到非线性结构和岩土等材料模型中,用于分析土-结相互作用体系的敏感性分析方法。本文将此敏感性方法应用到一个有实际工程背景的受双向地震荷载作用下的三维土-结相互作用体系中,通过有限差分法证明敏感性分析计算结果的高效性和正确性,验证了此方法应用到实际工程中的有效性和实用性。直接微分法由于计算得到的是半解析解,具有精确、高效、不受数值噪音干扰等优点,具有潜在重要的工程价值。Sensitivities of the FE response with respect to both model( material or geometry) and loading parameters represent an essential ingredient in studying the structures.This paper presents recent developments in FE response sensitivity analysis based on the Direct Differentiation Method( DDM) for displacement-based,force-based,and three-field mixed finite elements,with a focus on the extensions of the DDM to nonlinear material constitutive models of structural or geotechnical systems.DDM based response sensitivity analysis methods are used to analyze a real three dimensional nonlinear soil-structure interaction system under bi-directional seismic load to verify its accuracy,efficiency and applicability to engineering problems.The DDM has semi-analytieal solution and is accurate,effective and not disturbed by numerical noise,it has latent engineering value.国家自然科学基金(51261120376;51281220267); 冻土工程国家重点实验室资助(SKLFSE201405

    罗格列酮对压力超负荷大鼠血流动力学及心肌肥厚的影响

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    【目的】探讨过氧化物酶体增殖物激活受体γ(PPAR-γ)配体罗格列酮对压力超负荷大鼠血流动力学及心肌肥厚的影响。【方法】30只SD大鼠随机分为假手术组(n=9)和压力超负荷模型组(n=21),应用腹主动脉缩窄的方法制作压力超负荷模型,将制作模型后24h仍存活的16只大鼠随机分为压力超负荷(PO)组(n=7)和罗格列酮(PO+Ros)组(n=9)。罗格列酮组给予罗格列酮3mg/(kg·d)共8周。8周后测定血流动力学;称量心脏质量;放射免疫分析方法测量血浆肾素活性、血管紧张素Ⅱ和醛固酮。【结果】与PO组相比,PO+Ros组动脉血压降低(P〈0.05);+dp/dtmax升高(P〈0.05);心脏质量指数和左室质量指数降低(P〈0.05);血浆肾素活性、血管紧张素Ⅱ、醛固酮和胰岛素及血糖水平无明显差异(P〉0.05)。【结论】PPAR-γ配体改善压力超负荷性心肌肥厚和左室舒缩功能,降低动脉血压,其效应与血浆肾素血管紧张素系统无明显关系

    平成26年度版 教育実習におけるタブレット端末活用の指針

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    <臨床>複合アパタイトセラミックスインプラントを用いた人工歯根の臨床経験

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    Ceramic materials are physically and chemically stable with excellent affinity to tissues. It is well known that apatite ceramics, exhibit particularly excellent bony ankylosis with osseous tissues. The authors conducted implantation of apatite ceramics and obtained favorable results. An outline of these results is as follows: The apatite ceramics implants in the present studies have a two-piece structure-separated into an apatite-root and a Ti-core. A two-step method was used:the apatite-root is first implanted into the submucous bone tissuejand the Ti-core is set when ankylosis is completed. Prosthetic appliances have a double-structure consisting of an inner and outer crown working as a buffer mechanism. The crowns can be free-standing with no need for bridges or other anchoring to adjacent teeth
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