Design and Simulation of Low Power Low Voltage Rail to Rail Operational Amplifier and the bandgap reference

运算放大器是模拟和混合电路中被广泛应用的基本模块，其精度和稳定性决定着系统的性能，而CMOS轨对轨运算放大器以其优异的输入、输出电压范围等特点受到广泛的应用。本文主要针对CMOS轨对轨运算放大器及其辅助电路带隙基准源进行设计与仿真。 本论文首先针对国内外低压低功耗轨对轨运算放大器做了广泛的调查和研究，在吸收前人成果的基础上，设计了一个低压低功耗轨对轨运算放大器。运算放大器采用两级运放的结构。运放的第一级采用互补差分对结构以实现轨对轨输入，采用折叠式共源共栅结构实现第一级的高增益。采用3倍电流镜技术来实现输入级的跨导的恒定。输出级采用浮动电流源控制的互补甲乙类输出结构，提高了输出电压的范围和效...Operational amplifiers are analog and mixed circuits are widely used in the basic module, its precision and stability determine the performance of the system, and rail to rail CMOS operational amplifier with excellent input and output voltage range and so on are widely used. This article will focus CMOS rail to rail operational amplifier and the auxiliary bandgap reference circuit design and simul...学位：工学硕士院系专业：物理与机电工程学院物理学系_微电子学与固体电子学学号：1982007115232

Numerical modeling and biomechanical analysis of the human mitral valve

目的建立人体心脏二尖瓣仿真模型,模拟二尖瓣闭合的工作过程,分析二尖瓣各组件应力分布,探讨二尖瓣瓣叶和腱索的相互作用,并探寻腱索受力大小与腱索粗细之间的相关性。方法构建二尖瓣几何模型,在此基础上定义模型单元类型、材料属性、接触、载荷及约束,建立有限元模型,计算模型的应力、速度和位移等参数。结果瓣膜上的应力分布不均匀,后瓣叶亚区之间的裂口位置所受应力最大;不考虑腱索连接至瓣叶时,瓣叶负载后外翻至心房一侧;考虑腱索连接至瓣叶时,前、后瓣叶关闭良好;各腱索受力不同,与前瓣叶相连的支持腱索受力最大,腱索受力大小与腱索粗细之间的线性相关系数为0.954。结论瓣叶中心和后瓣叶亚区之间的裂口两处应力较大区域是临床上二尖瓣裂的常发生部位;与瓣叶相连的腱索可在瓣叶负载时,施加牵拉力使瓣叶不致发生翻转,前、后瓣叶恰好关闭;解剖结构粗壮的腱索受力较大。Objective To establish a numerical model of human mitral valve and simulate its closing process,so as to analyze stress distributions on the valve apparatuses,study the interaction between leaflets of mitral valve and chordae tendineae,and explore the relationship between the force of chordae tendineae and their thickness.Methods A geometric model of human mitral valve was constructed.On the basis of the geometric model,the finite element model was established by defining the element type,material attributes,contacts,loads and constraints.Parameters such as stress,velocity and displacement were calculated after solving the model.Results The stress distribution on the valve was non-uniform.The clefts between the scallops in the posterior leaflet were always under the highest load.When no chordae tendineae were attached,the leaflets turned over to the side of the atrium.When chordea tendineae were attached,the anterior and posterior leaflet could close up successfully.Different chordae tendineae applied different forces to the valve.The strut chorea tendineae attached to the anterior leaflet applied highest force among all the chordea tendineae.The correlation coefficient between the thickness of chordae tendineae and their force was 0.954.Conclusions The two zones with higher stresses,namely the center of the leaflet and the clefts between the three scallops in the posterior leaflet,are also the positions of mitral valve cleft in clinic.Chordea tendineae can apply the pulling force on the leaflets while the mitral valve is under load,thus the leaflets won't turn over to the side of atrium and the valve can close up in time.Chordea tendineae with thicker anatomic structure always apply a higher force on the leaflets.国家自然科学基金资助项目(61102137); 福建省自然科学基金资助项目(2011J01366); 福建省创新医学科研基金(2009-CXB-59

LED Color Analysis

主要对蓝光、绿光、白光lEd的色度特性进行分析,首先通过单色仪,分别测得蓝光、绿光、白光lEd的相对光谱功率分布并以色度学理论为基础,计算出光源主波长、色纯度、色温和显色指数.计算结果表明:蓝光lEd和绿光lEd主波长随标准光源的不同变化不大,色纯度比较高,分别在0.64和0.87左右,一般显色指数为-29和-14,显色性很差,不适合用来做照明光源.白光lEd主波长随标准光源的不同变化较大,色纯度相当低,接近0,一般显色指数为82,显色性很好,完全符合照明光源的要求.In order to study the color characteristics of light-emitting diode,the characteristics of blue,green and white LED colors are analyzed.Firstly,the spectral power distribution of blue,green,white LED is respectively measured by using the monochromator,and then on the basis of the theory chroma,the main light source wavelength,color purity,color temperature and color rendering index are calculated.The results show that blue LED and green LED dominant wavelengths change little with different standard light sources,and the color purities are relatively high,at 0.64 and 0.87,respectively,the general color-rendering is very poor for the index of-29 and-14,so these blue and green LED are not suitable to be used as lighting source.White LED dominant wavelength largely change with different standard light sources,and color purity is relatively low,near 0,color rendering is good for the general color-rendering index of 82, so white LED is in full conformance with the lighting requirements

N-取代苯基苯并咪唑类三价铱有机金属配合物、其制备方法与用途

本发明公开了一种N-取代苯基苯并咪唑类三价铱有机金属配合物，其制备方法以及在有机电致磷光掺杂型发光器件中的应用。该有机金属配合物的结构式为：或者其中，R1、R2分别独立选自氢、C1-C4的烷基、C1-C4卤代烷基、芳香基、稠环基团、苯胺基、咔唑基、芴基中的任意一种。该有机金属配合物可应用于具有层状掺杂型结构的有机电致磷光掺杂型发光器件中，作为发光层的客体材料，能够得到发光光谱波段在560-610nm之间的黄光材料，因此在单色、全色显示和照明白光器件中具有良好的应用前景

微藻细胞的连续气浮法采收

以螺旋藻为模型藻，较为详细地研究了藻细胞的絮凝行为以及回流比、藻液浓度、溶气时间和溶气压力因素等对藻细胞连续气浮采收效率的影响。结果表明，调节pH值为11—12可使藻液产生良好的絮凝性能；增大回流比、提高溶气压力、延长溶气时间和接触停留时间，可有效地提高气浮采收效率；藻液浓度较低时，气浮采收效率较高。所提出的连续气浮采收动力学模型可较好地拟合实验结果

1985年~2000年西藏地区景观格局变化及影响因子分析

利用西藏地区1985年及2000年两期遥感影像解译的数据,并结合GIS和统计软件,对西藏地区15年来景观格局变化特征进行分析。结果表明:1985年~2000年,西藏地区各景观要素之间发生了显著的变化,未利用地、居住地及建筑用地、灌木林地及疏林地面积增加,其中居住地及建筑用地增加的速度最快,增长率为46.6%;农用地、森林、草地、河流及湖泊、冰雪地面积减少,河流、湖泊和农用地面积减少率较大,分别为13.1%和10.4%;各景观要素发生相互转移,其中转移程度较大的是草地与未利用地,未利用地向草地转换了8031国家重大基础项目(973)(2005CB422005);国家重大基础研究前期研究专项项目(2005CCA05500)资

微藻细胞的连续气浮法采收

以螺旋藻为模型藻 ,较为详细地研究了藻细胞的絮凝行为以及回流比、藻液浓度、溶气时间和溶气压力因素等对藻细胞连续气浮采收效率的影响。结果表明 ,调节pH值为 11— 12可使藻液产生良好的絮凝性能 ;增大回流比、提高溶气压力、延长溶气时间和接触停留时间 ,可有效地提高气浮采收效率 ;藻液浓度较低时 ,气浮采收效率较高。所提出的连续气浮采收动力学模型可较好地拟合实验结果

低溶气压力下微藻细胞的气浮法采收

从理论和实验两方面探讨了通过添加微量表面活性剂以实现在较低溶气压力下进行微藻气浮采收的可行性。结果表明：添加适量的非离子型表面活性剂Tween 20可降低待分离体系的表面张力，改善微气泡的质量，在较低溶气压力下（≤0.25MPa)可获得良好的采收效果。无论是批式过程还是连续操作，当溶气水中含有浓度为100mg/kg的Tween 20时，采收性能都得到较大改善

低溶气压力下微藻细胞的气浮法采收

从理论和实验两方面探讨了通过添加微量表面活性剂以实现在较低溶气压力下进行微藻气浮采收的可行性。结果表明：添加适量的非离子型表面活性剂Tween 20可降低待分离体系的表面张力，改善微气泡的质量，在较低溶气压力下（≤0.25MPa)可获得良好的采收效果。无论是批式过程还是连续操作，当溶气水中含有浓度为100mg/kg的Tween 20时，采收性能都得到较大改善