Bifunctional thiophosphinamide catalyzed highly enantioselective Michael addition of acetone to (E)-2-azido β-nitrostyrenes and the subsequent reductive cyclization

We have proven that primary amine/thiophosphinamide incorporating (1R,2R)-1,2-diphenylethane-1,2-diamine is an efficient catalyst for the asymmetric Michael addition of acetone to (E)-2-azido β-nitrostyrenes. Under the optimal reaction conditions, the corresponding Michael addition products were obtained in excellent yields with almost perfect stereocontrol. Upon treatment with Et₃SiH/InCl₃, the Michael addition products could be successfully converted to the related 2-methyltetrahydroquinolines in acceptable yields with moderate to excellent diastereoselectivity and without appreciable loss in optical purity. This process provides a highly enantioselective pathway for the synthesis of biologically important 2-methyltetrahydroquinoline derivatives.     

带边界层的线性两点边值问题的打靶——小波配点法

本文将打靶法和小波配点法相结合，提出了打靶－小波配点数值算法，用于求解带边界层的常微分方程边值问题。文中给出了数值算例，并进行了分析，验证了这种方法对处理边界层问题的有效性。     

ZnCdse-ZnSe多量子阱中的激子发光

在77-300K温度下研究了Zn_1-xCd_xSe-ZnSe多量子阱(MQWs)的光致发光特性.首次在77K,Ar离子激光器的457.9nm激发下,在Zn_0.68Cd_0.32Se-ZnseMQWs中观测到5个发光带,其中三个发光带被归因于不同的激子发射:即n=1重空穴(HH)激子;n=l轻-重空穴(LH)激子和n=IHH激子同时发射两个纵光学声子的复合发光,并且n=1HH激子发光可延续至室温.     

ZnSe－CdZnse多量子阱光双稳器件的研制

本文采用电化学选择性腐蚀工艺对ＧａＡｓ衬底蚀孔，在其上获得了大面积具有光滑表面的Ⅱ－Ⅵ族半导体多量子阱外延膜．通过在其表面蒸镀反射膜，制成了高质量的Ｆ－Ｐ腔，制备出ＺｎＳｅ－ＣｄＺｎＳｅ多量子阱Ｆ－Ｐ腔光双稳器件．     

CONCISE POLARON MODEL TO THE CALCULATION OF BINDING ENERGY IN SOME STRONG-AND WEAK-COUPLING POLAR CRYSTALS

A new concise polaron model is proposed to study the ground state of polarons in some strong-and weak-coupling polar crystals. The ground state energy and binding energy of these materials are calculated numerically by iteration method. Results are in close agreement with the experimental data.     

An investigation on laser-diode-array pumped Nd: glass slab laser

Ａｎｉｎｖｅｓｔｉｇａｔｉｏｎｏｎｌａｓｅｒ－ｄｉｏｄｅ－ａｒｒａｙｐｕｍｐｅｄＮｄ：ｇｌａｓｓｓｌａｂｌａｓｅｒ￥ＨＵＷｅｎｔａｏ；ＺＨＯＵＦｕｚｈｅｎｇ；ＣＨＥＮＹｏｕｍｉｎｇ；ＪＩＡＮＧＺｈｏｎｇｈｏｎｇ（ＳｈａｎｇｈａｉＩｎｓｔｉｔｕｔｅｏｆ...     

用速率方程分析垂直腔面发射激光器的噪声

采用一种合理的噪声模拟方法，用速率方程对垂直腔面发射激光器的噪声特性进行了数值分析，在单模情况下计算了器件的自发辐射因子、输出功率、注入电流、阈值电流等参数与相对强度噪声、频率噪声以及线宽等特性的关系，计算结果与实验基本相符，对优化垂直腔面发射激光器的结构设计和应用条件有所裨益. 关键词：     

A New Isoflavone Glucoside from Astragalus membranaceus

TheAstragalusrootisaveryoldandwell-kn0wndrugintraditionalChinesemedicine,usedasanantiperspirant,adiureticandatonic.InourchemicalstudiesonRadixAstragali,weobtainedseveralc0mpounds.Thispaperdescribesthestructuralelucidationofanewis0flavoneglycoside,3'-meth0xy-5'-hydroxy-is0flavoneglucosideI.CompoundI,paleyellowneedle-crystals,mp232~234"C,withm0lecularf0rmulaofCzzHzz0lobased0ntheLD-MS[M K] 485.O847(Calc-485.O844),wasshownt0haveaphenolicgroupbyitsc0lor-reactionwith3?Cl3inethanolandthehyd…     

GaAs/AlGaAs量子线的制备和光致荧光谱

利用分子束外延材料的化学选择腐蚀和再生长制备出了GaAs/AIGaAs量子线并且测量了77K的光致荧光谱.也得到透射电子显微镜的照片. 关键词：     

准连续60W半导体激光侧面泵浦声光调QNd：YAG板条激光器研究

用准连续６０Ｗ激光二极管列阵侧面泵浦Ｎｄ：ＹＡＧ板条激光器，获得３．５ｍＪ的激光输出和峰值功率为７５ｋＷ的声光调Ｑ激光脉冲，脉冲幅度起伏小于±１％。对研究结果进行了分析。