大学生异性交往研究述评

在回顾异性交往的概念、基本现状和测评工具的基础上,分析了影响大学生异性交往的相关因素(包括生理变化、自我同一性、亲密关系),最后针对大学生异性交往的测评工具、现状探索和干预措施等面提出了需要进一步深入研究的问题。     

体扩散对TGFB单晶生长的影响研究

本文通过动态体视显微法研究了溶液流速对ＴＧＦＢ晶面生长速率的影响，结合晶胞参数和生长溶液的密度、粘度等物理性质的测定，得出了ＴＧＦＢ单晶生长时的体扩散系数约为１０－６ｃｍ２／ｓ．讨论了要消除体扩散的影响，用转晶法生长单晶时掣晶盘的转速不应低于５２ｒ／ｍｉｎ．     

城乡协调发展的经济学基础与核心机制构建

本文基于中国城乡协调发展的历史演变与现实要求,认为现阶段中国既要保证城市的发展,同时更要促进农村的快速发展,缩小城乡差距,增加社会公平,使效率与公平同时实现;进一步论证了效率与公平同时实现依赖于合理劳动分工的原理,揭示了现阶段城乡协调发展的经济学基础;最后提出基于劳动分工原理构建城乡协调发展的两种核心机制,一是建立合理的城乡分工机制,二是通过农业生产的区域专业化建立农村内部劳动分工机制。     

间接电氧化法合成L—磺基丙氨酸研制的成功

磺基丙氨酸是一种重要的生化试剂 ,在动物体内有着广泛的生理作用 ,在医药、化妆品、洗涤剂等行业的应用在国外已受到广泛关注 .以其为原料可合成抗爱滋病毒 (HIVI)、Herpes Simplex I病毒、球菌及杆菌的药物 ;聚磺基丙氨酸可抑制癌细胞的扩散而对未感染细胞无任何副作用 ;含磺基丙氨酸的护发剂可保持头发弹性和湿度 ,定型剂和染发剂可防止头发损伤 ,还可修复已损伤的头发并改善发质 ;以磺基丙氨酸二溴乙烷及丁氨二酸为主要原料合成的乙基丁氨二酸碘基丙氨酸 (EAC) ,以磺基丙氨酸、烷基马来酸酯为原料合成的磺基丙氨丁二酸酯作为洗涤助…     

利用PRP-6树脂制备高纯度全反式番茄红素

文中以番茄酱为原料,利用聚苯乙烯-二乙烯基苯共聚物（PRP-6树脂）吸附并经梯度洗脱制备出高纯度番茄红素,经紫外、红外、质谱和核磁分析,确认制得的样品为全反式番茄红素,经高效液相色谱检测样品纯度为99.8%。     

紧支撑正交小波的多项式滤波器

利用Reisz引理及特殊的余弦三角多项式,给出了一种构造紧支撑正交小波的多项式滤波器的算法,从而可以得到一系列特性各异的紧支撑正交的小波基,这为我们在应用小波分析的过程中从众多小波基中挑选出“好基”提供了可能。特别地,也可采用该方法构造出著名的I.Daubechies小波的多项滤波器及相应的小波,最后给出相应的数值算例。     

Portfolio managers' and novices' forecasts of risk and return: are there predictable forecast errors?

This study aims to investigate the individual behaviour that underlies the overreaction hypothesis by conducting a controlled experiment. Two areas that were not captured by previous research on the validity of the overreaction hypothesis are investigated. First, actual portfolio managers are employed as forecasters. Second a real‐world assessment task is given in the form of predicting the prices of stocks traded on the exchange on a real time basis. The purpose is to explore return expectations and risk perceptions of portfolio managers as well as financially unsophisticated investors by using point and interval forecasts provided for different forecast horizons in bull and bear markets. Contributions stem from three sources. (1) The use of financially sophisticated subjects for the first time in an experimental framework testing the overreaction hypothesis makes possible to control for the effect of expertise. (2) The use of different forecast horizons controls for the effect of forecast period. (3) The use of real‐time forecasts of specific stocks traded at the stock exchange, for the first time in an experimental framework testing the overreaction hypothesis enables to control for ecological validity. Discussions will be given as to the portfolio managers' versus naive investors' interpolating asset prices from past trends and hedging behaviour, due to their caution in projections of ranges for future prices. Copyright © 2002 John Wiley & Sons, Ltd.     

A mendelian gene for albinism in natural cave fish

Zusammenfassung Es konnte gezeigt werden, dass beim HöhlenfischAnoptichthys — neben zahlreichen anderen degenerativen Genen — ein Gen für Albinismus vorkommt.     

甘肃天水透辉石的烧陶试验及其节能效应

透辉石属Ca—Mg硅酸盐矿物,可配入普通陶瓷原料中,形成CaO—MgO—A_2O_3—SiO_2:四元体系。其共溶温度(1200℃±),且熔融温度范围比单一含Ca或含Mg硅酸盐矿物宽,可明显降低陶瓷烧结温度,缩短烧成时间.用甘肃天水透辉石所作的烧陶试验及机理研究表明.天水后裕沟透辉石矿床是很好的节能矿物原料基地.     

Controlling photons using electromagnetically induced transparency

It is well known that a dielectric medium can be used to manipulate properties of light pulses. However, optical absorption limits the extent of possible control: this is especially important for weak light pulses. Absorption in an opaque medium can be eliminated via quantum mechanical interference, an effect known as electromagnetically induced transparency. Theoretical and experimental work has demonstrated that this phenomenon can be used to slow down light pulses dramatically, or even bring them to a complete halt. Interactions between photons in such an atomic medium can be many orders of magnitude stronger than in conventional optical materials.