Perturbation analysis for the positive definite solution of the nonlinear matrix equation X-\sum_{i=1}^{m} A_{i}^{*}X^{-1}A_{i}=Q

Consider the perturbation analysis for positive definite solution of the nonlinear matrix equation $X-\sum_{i=1}^{m}A_{i}^{*}X^{-1}A_{i}=Q$ which arises in an optimal interpolation problem. Two perturbation bounds for the unique positive definite solution are obtained, and an explicit expression of the condition number for the unique positive definite solution is derived. The theoretical results are illustrated by several numerical examples.     

Numerical methods for portfolio selection with bounded constraints

This work develops an approximation procedure for portfolio selection with bounded constraints. Based on the Markov chain approximation techniques, numerical procedures are constructed for the utility optimization task. Under simple conditions, the convergence of the approximation sequences to the wealth process and the optimal utility function is established. Numerical examples are provided to illustrate the performance of the algorithms.     

Insight into copper-catalyzed decarboxylative thiolation of carboxylic acids in the gas phase

Organocopper complexes bearing bidentate nitrogen ligands were synthesized in the gas phase by electrospray ionization mass spectrometry. Gas-phase decarboylative thiolation reaction was carried out in the ion-trap analyzer by collision-induced dissociation and ion-molecule reaction. The carboxylic acids were finally converted to thioethers as a neutral loss via collision-induced dissociation. During this process, copper acetate acted as a catalyst, and the valence state change of copper was observed. Meanwhile, the mechanism of decarboxylative thiolation was examined. This reaction was also suitable for different carboxylic acids and bidentate nitrogen ligands in the gas phase.     

近50年鄱阳湖流域降水时空特征及其对水文过程的驱动

依照鄱阳湖流域79个国家气象站的逐月降水资料(1961~2010年),基于BCC-CSM全球气候系统模式预估数据(2014~2050年),对鄱阳湖流域降水变化趋势和空间分布变化趋势进行分析。选取赣江外洲站1961~2010年逐日径流量和1960~2010年年代径流量、输沙量数据,利用HBV水文模型、SPSS统计软件对赣江流域面雨量及径流量进行相关性分析,探讨降水特征对水文过程的驱动性。结果表明:1961~2010年间鄱阳湖流域降水量总体略呈上升趋势,降水日数呈下降趋势,降水强度增加、降水时间分布不均匀性更加明显,旱涝等极端事件发生更为频繁;年内变化特征为分布不均匀,以4~6月为汛期,其中6月降水量最大;空间分布特征总体表现为东部降水大于西部,丘陵地区降水大于平原地区;降水变化为径流量、输沙量变化等水文响应的主要驱动力,赣江流域面雨量及径流量呈显著线性相关,相关系数高达0.909。未来37年降水呈现略上升趋势,但趋势不显著。若鄱阳湖流域长期存在高能源需求及高温室气体排放,则洪涝灾害发生将更为频繁。研究为预测鄱阳湖流域水资源科学管理提供科学依据。     

高功率半导体激光器光纤耦合实验研究

为进一步提高光纤耦合半导体激光器的输出功率,提出了一种多单管半导体激光器通过台阶分布、光束精密准直及自由空间合束实现高功率光纤耦合输出的方法,该方法具有结构简单、光学元件易于加工、耦合效率高等优点。采用这种方法对5只封装在次热沉上的单管半导体激光器开展了芯径100 m、数值孔径0.22多模光纤的耦合实验研究,当工作电流为7.0 A时,光纤连续输出功率为21.8 W,亮度为1.83 MW/(cm2sr) ,耦合效率为70.32%。     

用手性配体改性铝锂试剂对芳香酮的还原

用手性一元酮作辅助配体,与１,２,５,６－二丙酮甘ｉＡｌｈ５对芳香酮进行对映选择 的,得到光学活性产物８个。通过与α－乙酰氧基－Ｌ－丙酰氯生成非对映异构体酯,经气相色谱分析,芳酮挑学产率为２３．３￣７１．２％。初步探讨了配体之间对称性匹配的情况。     

由激光诱导荧光方法探测光碎片分子取向的理论研究

采用密度矩阵方法,推导了从激光诱导荧光(LIF)强度中抽出光碎片取向参数的表达式.光碎片的取向由分子态多极矩描述.用于解离母分子和激发碎片分子的激光均为线偏振光,而探测荧光为非偏振光.激光诱导荧光强度是光碎片分子初始态多极矩、线强度因子和解离-激发几何因子的函数.光碎片的取向参数可以由测量荧光偏振比和计算动力学因子而获得.     

新型水溶性配体-负载金属氢甲酰化催化剂:TPPTS-Rh/SiO2

考察了几种硅胶负载贵金属催化剂和HRhCO(TPP)3催化剂的1-己烯氢甲酰化反应,对Rh/SiO2、 HRhCO(TPPTS)3/SiO2 和TPPTS-Rh/SiO2上的1-己烯氢甲酰化结果进行了比较.结果表明, TPPTS-Rh/SiO2催化剂的醛的选择性和醛的正异比n/b接近HRhCO(TPPTS)3/SiO2 的相应的催化性能,而远高于Rh/SiO2的相应的催化性能, 7.0 MPa高压下TPPTS-Rh/SiO2催化剂的活性大幅度增加,达到0.0692 S-1.实验排除了其他可能,认为是含有孤对电子的TPPTS 和Rh/SiO2中高度分散的Rh粒子产生了化学键的作用,形成了具有匀相性能的支撑水膜多相催化剂: TPPTS-Rh/SiO2.