非完备市场下上市公司融资行为的模型分析

资本结构经典理论存在着内在的缺陷,难以合理解释现实世界中的企业融资行为．由此,提出在非完备市场下,存在信息不对称和交易成本的资本结构决策模型,以期揭示中国上市公司基于逆向选择的融资选择行为机理．从而很好地解释了中国上市公司股权过度融资的现象．     

Polyacrylonitrile/Graphene-Based Coaxial Fiber-Shaped Supercapacitors

Supercapacitors have huge potential applications in the field of wearable electronic devices, such as flexible displays, flexible biosensors and implantable multimedia devices, due to their high-power density, fast charge-discharge rates, long cycling life, and relatively simple configuration. In this paper, we demonstrated hierarchically porous and continuous reduced graphene oxide-polyacrylonitrile@polyacrylonitrile(rGO-PAN@PAN) coaxial fibers with certain strength, excellent electrochemical performance through coaxial wet spinning and thermal reduction. Coaxial fibers are carbonized at high temperature and have a graded porous structure with a conductivity of 1 703 S/m. The areal specific capacitance of the supercapacitor assembled by polyvinyl alcohol/sulfuric acid(PVA/H_2SO_4) gel electrolyte is 11.56 mF/cm~2, and its energy density reaches 0.21 mW·h/cm~3, showing good electrochemical performance. Graphene-based coaxial fibers prepared by wet spinning have a great prospect of application in electronic devices due to their excellent properties.     

络合Ca2+的Au/巯基环肽自组装单层膜的交流阻抗研究

环肽在自然界中分布广泛,植物、动物、低等海洋生物、微生物、细菌、病菌等都含有微量的环肽。这些环肽的含量虽然低,但其中不少具有明显的生理活性,因此受到国内外许多化学家、生物学家和药学家的重视[1-2]。自组装单分子层膜(Self-Assembled Monolayer,SAMs)是固液界面通过化     

电子束蒸发太阳能电池窗口层ZnO薄膜

用电子束蒸发法在玻璃基片上制备太阳能电池窗口层ZnO薄膜,并在氧气环境下对其在400～500℃的温度下退火1h．通过X射线衍射、电镜扫描、透过率光谱等手段测试和分析所制备的薄膜,结果表明：当薄膜未经过热处理时,薄膜中含有大量的单质锌;当薄膜经过400℃退火后,薄膜逐渐结晶,并且其物相成分基本是ZnO;当退火温度逐渐升高到500℃时,晶粒长大,晶化程度提高,对可见光和近红外光的透过率也增大,平均值可达90％,此时所制备出的ZnO薄膜适合于作为太阳能电池的窗口层。     

Researches on the Structure and Properties of Mullite Solid Solution Made from Industrial Waste

1 INTRODUCTION The mullite has excellent properties of high tem- perature thermodynamics and mechanics, such as corrosion resistance, creep resistance, thermal shock resistance and high hot strength at high temperature. So it can be used as the inner lining of industrial furnace, thermal insulator material, crucible, protec- ting tube and electronic packaging material, which are widely used in such industries as metallurgy, ceramics, cement, and fireproof materials[1]. So far there has no …     

胸腺五肽在NH-1树脂上的离子交换过程研究

研究了胸腺五肽(TP5)在NH-1树脂上的离子交换过程.结果表明,在pH 2.O的条件下,其等温吸附过程符合Langmuir等温吸附方程,最大吸附量为221.07mg/g wet resin;静态吸附动力学的研究结果显示,NH-1树脂对TP5的吸附过程主要受颗粒扩散控制影响,TP5的颗粒内扩散系数为4.50×10-9cm2/s;对比Nernst-Planck与Fick动力学模型,可用Fick动力学模型来描述TP5在NH-1树脂内的颗粒扩散行为,其有效扩散系数为5.58×10-9cm2/s;采用固定床吸附数学模型,对TP5离子交换柱行为进行模拟,该数学模型考虑了颗粒扩散、轴向返混、非线性平衡以及液膜扩散.结果显示,模拟数据与实验结果具有较好的符合.     

CdGd2(WO4)4单晶的磁性研究

磁化曲线σ-H和电子自旋共振谱（ESR）表明钨酸钆镉（CdGd2（WO4）4,简称CGW）单晶具有磁各向异性．当外磁场等于零或者较小时,难磁化方向的磁化强度为负值,利用各向异性场对此进行了解释,并由ESR谱计算出了各向异性场．     

白光LED用钨/钼酸盐红色发光材料研究进展

红色发光材料的性能对白光LED的显色指数和色温有着极其重要的影响,本文主要介绍了白钨矿型钨/钼酸盐、双钙钛矿型钨/钼酸盐以及复合型钨/钼酸盐等几大体系红色发光材料的结构组成、发光性能以及研究成果,并对钨/钼酸盐红色发光材料的未来前景进行展望.     

青蒿素的制备、用途和展望

青蒿素是含有过氧桥的新型倍半萜内酯,其衍生物有青蒿琥酯、蒿甲醚和二氢青蒿素等。青蒿素是有效的疟痰治疗药物,此外它还具有抗肿瘤、抗寄生虫、影响免疫等药理作用。对青蒿素及其衍生物进行了综述。     

数据挖掘在高校图书馆的应用

介绍了数据挖掘技术的基本含义和任务,分析了其在高校图书馆工作中的应用,阐述了数据挖掘对高校图书馆的发展和数字化进程的重要性。