二阶线性微分系统解的Sturm比较定理

本文利用几个矩阵形式的微分恒等式，建立了关于二阶线性微分系统（１）的预解及其导函数的Ｓｔｕｒｍ比较定理，推广了若于经典结论。     

昆明的城市自然植被和植物区系

对昆明城区范围内自然分布的植被和植物区系进行了初步研究。根据分布的植物区系特征和所调查样地分布的生境，划分出１０种群落类型，这些类型的分布与人为干扰况形式及强度有关；自然分布于城市的一共有１９０种种子植物，对植物的科及其属、种组成，它们的一些特征进行了初步分析，植物区系成分以一年生植物和通常认为的杂草植物为主，而其中不乏有用的植物．     

芳氧乙酰基毗唑啉酮类螫合剂的合成

本文合成了8种新的吡唑啉酮螫合剂,通过元素分析和光谱分析证实了其结构,并初步考察了它们对Cu(Ⅱ)、UO_2(Ⅱ)、La(Ⅲ)的萃取性能。     

SOD与酪氨酸酶共存时各自的活性

本文采用NBT(氮兰四唑)光还原法,测定了在酪氨酸酶存在下SOD酶的活性,并采用生成DOPA红的方法测定了SOD酶存在下酪氨酸酶的活性.并做了一系列干扰实验,实验结果指出:在酪氨酸酶存在下SOD催化O_2~??+O_2~??+2H~+??H_2O_2+O_2的反应活性降低,而在SOD存在下酪氨酸酶催化DOPA生成DOPA红的反应有明显抑制作用.     

TiB_2粒子增强Ti-Al基复合材料的合成机理

采用Ti、Al和B元素粉末,经燃烧反应合成了TiB_2粒子增强的Ti Al金属间化合物基复合材料,并用DSC、EMPA和XRD等方法研究了其合成机理。结果发现,Ti和Al粉末间的放热反应促进了 TiB_2粒子的形成,所形成的 TiB_2粒子的尺寸约为2μm。将所得复合材料重熔后,TiB_2粒子的尺寸、相对含量和形貌没有明显变化,并且其显微组织比铸态Ti Al基合金组织明显细化。     

方柱非定常绕流与涡激振动的数值模拟

为了研究二维刚体方柱的涡激振动和非定常绕流,利用计算流体力学软件Fluent6.0,引入雷诺应力模型求解不可压粘性流体Navier-Stokes方程,将Newmark-β方法的代码嵌入用户自定义函数(UDF)同软件连接来求解方柱的动力响应.用分块的方法建立初始网格,方柱和流场的耦合作用通过Fluent的动网格技术来实现,进行雷诺数从7000到42000范围内的模拟.得到静止方柱的升阻力系数和涡脱频率,其中雷诺数为22000结果与试验一致;同时得到方柱振动的位移和速度时程,以及"频率锁定"、"拍"和锁定段的位移"失谐"现象.     

蒙特卡罗技术在工程成本预测中的应用

对工程施工成本的不确定性进行了研究,根据各分项工作成本符合β分布的特征,提出了用蒙特卡罗技术对工程施工成本进行模拟的方法、步骤以及实现某计划成本值的风险计算方法,其结果有助于施工企业的成本风险决策与控制.     

Positioning accuracy and reliability of GALILEO, integrated GPS-GALILEO system based on single positioning model

A kind of uniform reliability index suitable for the code and phase observations is presented and used in reliability evaluation of satellite systems. Then, based on 25 stations of Crustal Movement Observation Network of China, satellite visibility, positioning availability and observation reliability of GPS, GALILEO and integrated GPSGALILEO are calculated and analyzed in detail. Simulation results reveal that the satellite visibility of GALILEO is superior to that of GPS. Given positioning accuracy, horizontal positioning availability of GALILEO is consistent with that of GPS, but its vertical positioning availability is superior to that of GPS. However, the integrated GPS-GALILEO is shown to be superior to each of the single systems in the aspects of positioning accuracy and availability. The reliability of code and phase observations based on GALILEO and integrated GPS-GALILEO system is superior to that of GPS both in spatial and temporal domains on the whole. The new reliability index presented is simple to calculate and reflects reliability differences of different satellite systems.     

A family net of giant pandas in the Tangjiahe Natural Reserve： Assessment of current individual migration

In the present study, formalin-fixed feces, oligonucleotide fingerprinting and SRY-gene based sexing were used to construct a family net for giant pandas in the Tangjiahe Natural Reserve and to assess contemporary gene flow （migration） in this population. A total of 124 fecal samples were attributed to 37 individuals （22 females and 15 males） that were then analyzed for family relationships. Based on DNA fingerprints, the deduced family net revealed the following facts： （i） First-order relatives possessed similarities from 50% to 90%, and similarities between unrelated individuals or distant relatives were as high as 77%, indicating that the Tangjiahe pandas are characterized by high genetic similarity; （ii） 15 matings were identified and 5 ones occurred between close relatives, implying that there is potential for inbreeding to impact the pandas; （iii） four mating pairs and 5 offspring presented long distance migrations, demonstrating the intra-reserve habitat is continuous; （iv） four pairs of full sibs （also female-male dyads） dispersed short distance and all of them gave birth to highly inbred offspring, reflecting long distance migration is vital for inbreeding avoidance; （v） 17 adult individuals dispersed short or moderate distance and formed three clusters on the landscape, indicating that it is necessary to find out whether there is a negative factor impacting the pandas.     

国有商业银行上市的难题及对策

随着2004年的到来，金融业2006年“入世”大限的逼近，国有商业银行上市的话题愈演愈烈。本文直面国有商业银行上市现状，分析四家银行上市的难题，并提出了解决措施。