Motion Simulation of a New High Overload Flight Simulator

提出一种新型的基于绳牵引并联机器人技术的飞行模拟器,针对其大过载机动特性进行仿真分析。首先根据绳牵引并联机器人理论,设计了9根绳牵引具有6自由度的运动平台;通过建立平台动力学模型,设计了对干扰项进行补偿的前馈PD控制率;其中前馈项主要确保动态过程中绳索处于张紧状态。进一步给出了系统控制稳定性分析;并以大过载机动和单自由度俯仰振荡运动为例进行了数值仿真。分析结果表明,在大过载机动情况,瞬时正加速度超过4 g,平台位置能够迅速衰减并稳定;基于绳拉力前馈,可以避免绳索松弛,能够满足飞行员过载训练;俯仰运动也具有较好的跟踪特性。研究成果可为进一步分析工作空间、动态特性及控制稳定性等奠定基础,为绳牵引并联支撑的飞行模拟器设计提供指导与依据。A new kind of flight simulator based on the cable-driven parallel robot was proposed, and the over-load maneuver properties were emphatically analyzed. According to the fundamental theories of cable-driven parallel robot, the motion platform suspended by nine cables with a six-DOF is designed. The dynamic equations of the platform is established, and a PD control law incorporating feedforward term and disturbance compensation term is given. The stability analysis of control law is also made. Finally, numerical simulations of overload maneuver and pitch oscillation are taken as examples, and results show that the platform can achieve a high overload with more than 4 g, meanwhile the position attenuates and tends to be stable in a short time. The cable tension is also guaran-teed to be positive and secure during the motion process. Moreover, the case of pitch oscillation shows a good track-ing property. Researches studied above could lay on foundation for the workspace analysis, dynamics and control stability, and furthermore, provide guidance and evidence for the practical design of flight simulator.航空科学基金（20141368007）; 福建省自然科学基金计划（2016J05134）资

Bank Credit Policy and Real Estate Bubble

我国房地产业从20世纪80年代开始兴起，90年代发展壮大，近20年的发展取得了令人瞩目的成就，不仅很快改善了居民的居住质量，而且推动了中国经济的快速增长，已经成为国民经济的基础产业和支柱产业之一。我国从1998年房地产价格不断上飙升，房地产投资出现了过热的迹象，而银行的信贷支持则对房地产价格推升居功厥伟，不论是房产开发方面还是个人房贷方面。有鉴于美国次贷危机造成的重大损失，我国金融监管机构加强了对银行信贷和房地产业的监控，已相继收缩银根和地根，收到了初步的成效。 本文从银行信贷政策对房地产业的信贷支持角度出发来研究银行信贷扩张政策与房地产泡沫的内在关系。通过国内外的实际案例和近来发生的美国次...China's real estate industry has made remarkable achievements in nearly 20 years，from the beginning in the 1980s to the development and expansion in the 1990s, which is quickly improved the living quality of the residents and promoted China's rapid economic growth. Now China's real estate has become the basic industries of national economy and pillar industries. But in recent years, the prices of ...学位：经济学硕士院系专业：经济学院财政金融系_金融工程学号：2005130096

美国中小企业融资途径刍议——兼谈对完善我国中小企业融资体系的启示

本文介绍了美国中小企业的融资体系,并结合我国民营中小企业融资现状,吸取美国成熟作法,提出了完善我国中小企业融资途径的对策

Application Research on the Model of the Performance Evaluation of Enterprise Informatization

基于平衡记分卡(BSC)原理,从财务、业务流程、客户服务、战略与发展四个角度构建企业信息化绩效评价指标体系;依据BP神经网络原理,建立用于评估企业信息化绩效水平的BP神经网络模型,并结合算例进行仿真模拟,证明该模型的评价精度令人满意,有较强的实践意义。厦门市社会科学研究立项课题(编号:200848

我国商业银行与外资银行合作探讨

在国际金融业并购的背景下 ,中国银行业面临入世后的竞争压力 ,吸收外资不仅能增强国内商业银行实力 ,更重要的是能给银行带来了先进的管理理念 ,把国内商业银行日益改造成符合国际标准的银行 ;对外资银行而言 ,与中资银行合作乃绕过管制 ,低成本向中国市场扩张 ,实现本土化发展战略的最佳选择

盖层特性对CO_2埋存逃逸速度的影响

CO2地下埋存盖层逃逸是判定其埋存可行性的重要因素之一。通过理论分析分别建立了盖层渗透、盖层裂隙或者油井、盖层扩散三种气体逃逸与盖层特性之间的关系,并进行了盖层特性对三种逸出方式的影响分析,以及三种逃逸快慢之间的对比。结果表明:初期以渗透逃逸为主,但随着埋存年限的增加,气体盖层渗透减弱,扩散逃逸占主要地位

Optimum Design of Die Casting Die for Aluminum Alloy Microscope Arm

针对L形窄长铝合金显微镜立臂,安装孔多,位置精度高和要求外观表面一次成形不再后续加工等特点,采用CAE模拟分析技术,优化压铸工艺及模具结构,实现低成本制造模具,小吨位压铸机上安装大尺寸模具。并解决了试模中出现的局部裂纹、表面流痕和抽芯过程中铸件易翻转等问题。经批量生产验证,该模具工作稳定可靠,铸件质量达到要求。CAE analysis was applied for optimizing the die casting process & die structure to meet the requirement of precision assembling of its many fixed holes and one-step forming of its surface for the narrow & long microscope arm.Finally the die was manufactured with low cost successfully on a small tonnage die casting machine completely free of cracks,flowing marks or casting overturn that occurred during the trial test.The die functioned steadily with castings of required quality in volume production.福建省教育厅科技计划项目(JB05269);; 福建省自然科学基金项目(2007J0170

Pd Nanoparticles Encapsulated in Hollow Mesoporous Aluminosilica Nanospheres as an Efficient Catalyst for Multistep Reactions and Size-Selective Hydrogenation

最近,具有中空核壳结构的纳米材料在催化领域中有着深入的研究和广泛的应用.在本文中,我们使用一种简单易行的方法合成了一种包裹钯纳米颗粒的中空介孔硅铝酸盐纳米球(简写为Pd@HMAn).首先,通过一种先原位合成钯纳米粒子再对其进行二氧化硅包裹的方法,在brIJ56-环己烷-水的反相胶束中合成了具有核壳结构的包裹钯纳米颗粒的二氧化硅纳米球(简写为Pd@SIO2).然后,使用CTAb,nA2CO3和nAAlO2试剂,通过简单的碱性条件下刻蚀Pd@SIO2的过程,我们成功得到了具有多孔性能的中空核壳型Pd@HMAn纳米催化剂.由于硅铝酸盐外壳具有酸催化作用,并且内核钯纳米颗粒又是一种高活性的催化媒介,因此,这种复合的多功能纳米催化剂能够很好的应用于多步催化反应中.此外,通过一个简单的热处理的方法,能够缩小硅铝酸盐外壳上的孔道,我们发现这种孔道调节后的Pd@HMAn纳米催化剂在尺寸选择性氢化反应中有很好的应用前景.In this work,yolk-shell structured Pd@hollow mesoporous aluminosilica nanospheres(designated as Pd@HMAN) have been successfully fabricated by a straightforward synthetic route.Core-shell Pd@SiO2 nanospheres were firstly obtained by silica coating of in-situ synthesized Pd nanoparticles in a Brij56-cyclohexane-water reverse micelle system.Simply by alkaline etching of as-prepared Pd@SiO2 core-shell nanospheres in the presence of CTAB,Na2CO3 and NaAlO2,Pd@HMAN particles with high porosity were obtained.As the mesoporous aluminosilica shells can serve as acid catalysts,and the Pd yolks can be applied to catalytic hydrogenation,the as-prepared Pd@HMAN can be used as a stable multifunctional catalyst for multistep reactions.Moreover,due to their adjustable pore parameters,Pd@HMAN after simple thermal treatment can be further applied in the size-selective hydrogenation.ProjectsupportedbytheMinistryofScienceandTechnologyofChina(No.2011CB932403); theNationalNaturalScienceFoundationofChina(Nos.21131005;21021061;20925103;20923004); theFokYingTungEducationFoundation(No.121011)~

一种增益自举运算放大器的分析与优化设计

基于开关电容的流水线ADC设计中,运算放大器的建立时间和精度是关键指标。而增益自举运算放大器的建立时间分析比较复杂。本文通过理论推导和模型简化的方法分析其主运放和辅助运放的单位增益带宽及相位裕度对建立时间的影响。提出了一种P型与N型传输函数相同的辅助运放电路,并以此设计了一个高速、低功耗的自举运算放大器