Behavioral Finance analysis of China's IPO underpricing

新股首次公开发行问题一直备受学术界的关注，IPO抑价之谜更是金融界经久不衰的热点话题。所谓IPO抑价是指新股发行价低于上市后首日交易的收盘价，投资者认购新股能够获得超额报酬的一种股票市场运行状况。长期以来对于IPO抑价的理解主要集中于一级市场新股定价过低和二级市场首日收盘价过高两方面。对于我国IPO抑价问题，早期学者们认为：严格的发行管制、非市场化的新股发行制度使得IPO在发行时定价过低，造成了我国IPO高抑价现象。但是，在经历了新股发行监管方式和发行定价方式的多次改革后，我国IPO高抑价现象仍然是一如既往的存在。IPO询价制度的实施，虽然在一定程度上改善了IPO高抑价现象，但并没有消除IPO...Abstract The problems of Initial public offerings especially the mystery of IPO under-pricing have been a major concern in the financial circles and academic one. There is a phenomenon of IPO under-pricing that new shares issued at a price lower than the first dealing day’s closing price; and IPO investors consider that they will be able to get an excess return. There are mainly two explanations ...学位：工商管理硕士院系专业：管理学院工商管理教育中心（MBA中心）_工商管理硕士(MBA)学号：1792009115062

Study of the Characteristic and Parameters of Semiconductor Material

提出超晶格 (Al As/ Ga As)和应变超晶格 (Gex Si1-x/ Si,Inx Ga1-x As/ Ga As)光伏效应的机理 ,测量了不同温度下的光伏谱 ,光伏曲线反映了台阶二维状态密度分布并观察到跃迁峰 .计算了导带和价带子带的位置和带宽 ,根据宇称守恒确定光跃迁选择定则 ,对跃迁峰进行指认 .研究了光伏随温度变化、激子谱峰半高宽随温度和阱宽的变化 ,讨论谱峰展宽机制中的声子关联 ,混晶组分起伏及界面不平整对线宽的影响 .测量了元素和化合物半导体单晶材料的室温、低温下的表面光电压谱 ,推导了有关计算公式 ,计算得出电学参数 (L、n0 、μ、S、W)、深能级和表面能级位置、带隙和化合物组分 ;分析了电学参数的温度关系 ;由双能级复合理论 ,研究了少子扩散长度与深能级关系 ,计算了深能级浓度和参数 .在不同条件下研制了二氧化锡 /多孔硅 /硅 (Sn O2 / PS/ Si)和二氧化锡 /硅 (Sn O2 / Si) ,测量了它们的光伏谱 ,分析表明它们存在着异质结 .当样品吸附还原性气体 (H2 、CO、液化石油气 )时 ,光电压有明显变化 ,因此可做为一种新的敏感元件 .分析了它们的吸附机理 ,计算了有关参数The mechanism of the photovoltaic effect for superlattices(AlAs/GaAs) and strained superlattices(Ge xSi 1-x /Si,In xGa 1-x As/GaAs)are discussed. The photovoltage spectra at different temperatures have been measured. The curves of SPV reflect the step like distribution of two dimensional state density, and transition peaks have been observed. The levels and bandwidths of the subbands have been calculated. The transition speaks are assingned according to the selection rule for optical transition based on the conservation law of parit. The changed in photovoltage with temperature, the full width of half maxium of the transition peaks as a function of temperature and well width for different samples are investigated. The influences of exciton phonon coupling, alloy disorder and interface roughness on the broading mechanism of the transition peaks are discussed. The surface photovoltage of element and compounds single crystal semiconductors are measured at room and low temperatures. Some calculation formules are derived. The electrical parameters (L,n 0,μ,S,W),deep levels and surface level, energy gap and composition of the compounds are determined. The temperature dependence of the electrical parameters are analyzed. The dependence of minority carrier diffusion length on deep level are studied by double level recombination theory. The concentration and parameters of deep levels are calculated. Tin Oxide/Porous Silicon/Silicon(SnO 2/PS/Si)and Tin Oxide/Silicon are fabricated at different conditions. The photovoltage spectra of SnO 2/PS/Si and SnO 2/Si have been studied. It is shown that there exist heterojunctions in SnO 2/PS/Si and SnO 2/Si. The photovoltage changes evidently when the sample absorbes reducing gas (H 2,CO,liguified petroleum). The experimental results indicate that SnO 2/PS/Si or SnO 2/Si is a good material for gas sensor. The mechamism for the gas absorption of SnO 2/PS/Si and SnO 2/Si are discussed. The parameters are calculated.国家自然科学基金资助项目!(技准 36 1号 ;6 86 6 0 52 ;;59172 10 1) ;; 教育部科研资助项目 ;; 福建省自然科学基金资助项目!(F950

EFFect of 1-MeV Electron Irradiation on the PerFormence of Al Ga1- As/GaAs Heteroface Solar Cell

对AlXgAl-XAS/gAAS异质面太阳电池经l-MEV电子辐照前后的性能变化进行实验研究和数值拟合分析.讨论了电池性能衰退的主要原因，并提出了如何提高AlXgA1-XAS/gAAS异质面太阳电池的抗电子辐照能力的方法.The changes of perFormance of Al Ga1- As/GaAs heteroface solar cell beFore and aFter 1-MeV electron irradiation have been studied by experiments and numerical Fitting.The major reasons For the degradation of the cell perFormance are discussed and a method For improving the radiation resistance of the cell is proposed

GAN_(1-x)P_x三元合金的MOCVD生长

用金属有机化学气相淀积技术在蓝宝石衬底上成功外延了高P组分的GaN_(1-x)P_x 三元合金。俄歇电子能谱深度剖面结果表明在GaN_(1-x)P_x 中P的掺入量最高达到20%且分布均匀；X射线光电子能谱价态分析证实了外延层中Ga-P键的存在。对不同P组分的GaN_(1-x)P_x 样品进行了低温光致发光（PL）测试，与来自GaN衬底的带边发射相比，随三元合金中P组分的变化，GaN_(1-x)P_x 的PL峰呈现出了不同程度的红移。在GaN_(1-x)P_x 的PL谱中没有观测到有关GaP的发射峰，表明该合金材料没有发生相分离