金融危机带给非垄断央企的反思

近两年来席卷全球的金融危机对我国经济造成很大影响,对一些跨国非垄断央企影响更甚。通过一个非垄断央企与同行业竞争民企的比较,进行了反思,旨在增强央企员工的忧患意识,调动其工作积极性,推进央企的改革进程。     

Siliceous microplankton fluxes and seasonal variations in the central South China Sea during 1993-1995:monsoon climate and El Ni(n)o responses

Seasonal variations of radiolarian and diatom fluxes in the central South China Sea during 1993-1995 were overwhelmingly controlled by monsoon climate. Radiolarian and diatom increased obviously during the Northeast (from November to February) and Southwest (from June to September) monsoons and decreased during the periods between the monsoons. The change of circulation driven by the monsoons improved water exchange in the different areas that brought rich nutrient materials for the surface microplankton, thereby enhancing radiolarian and diatom fluxes. Variation of radiolarian flux coincided with organic carbon flux, surface primary and export productivities. High radiolarian flux corresponded to high surface primary productivity. Radiolarian and diatom fluxes raised abnormally during 1994-1995 could be attributed to the El Ni(n)o event during the period.     

关于Runge—Lenz矢量应用的探讨

为了能方便地研究平方反比有心力场质点的运动规律，通过引入Runge-Lenz矢量，十分简便地得到了质点的轨道方程，能量判据和卢瑟福散射公式，并能简单处理索莫菲的电子椭圆轨道理论，这一方法可以简化公式推导，降低掌握有心力知识的难度。     

Human impact on avian diversity in rural Mediterranean areas

Human activities influence the biodiversity of Mediterranean ecosystems and are involved in the transformation of natural habitats into farmland. We surveyed birds using the point count method on 288 plots at a 50-m radius in three altitudinal landscapes with different rural character in spring and autumn. The results showed that bird species richness in the study area was high (74 species). High total species richness was found in the upland rural landscape characterized by mixed land use and high landscape diversity. The applied richness of total, resident and Sylviidae species illustrated a definite preference for villages with a low human population during the breeding season. Positive and significant correlations were found between rural settlements and Fringillidae, Sylviidae and total bird richness at both periods in the three landscapes. Finally, a clear dependence on the land use/land cover type was shown for the five recorded priority species.     

线电荷椭圆环中心轴线势分布

运用椭圆积分的理论和教学方法，给出线电荷椭圆环中心轴线势分布的解析表达式，进行了有关的讨论，指出线电荷椭圆环中心轴线势具有的重要特性。     

CFB锅炉中心筒改造探讨

探讨了CFB锅炉中心筒改造的必要性与可行性，重点介绍了CFB锅炉中心筒的改造方案，以提高分离器效率，延长中心筒使用寿命，节约检修费用。     

咸丰末年肃顺对清廷中枢决策体制之影响

肃顺是咸丰末年对朝政最具影响力之大臣。咸丰朝时,由于军机大臣不堪重用,肃顺凭借自己过人的才华开始在清代政坛崭露头角,成为咸丰帝倚重之臣。至"祺祥"时期,肃顺达到了权力的巅峰,将军机处置于自己的直接控制之下,极大地影响了清廷中枢决策体制。     

相干分布式信源中心波达方向估计算法

针对移动通信中由本地散射导致的分布式信源的中心波达方向估计问题,根据分布式信源角度信号密度对称的约束条件,将相干分布式信源方向向量整理为点信源方向向量与实向量的Schur-Hadamard积,并构造相应的二阶统计量,提出了一种仅需利用二阶统计量就能直接估计中心波达方向的新方法。该算法与传统谱峰搜索类算法和经典子空间类算法相比,无须谱峰搜索和任何特征值或奇异值分解,有效地降低了计算量;所利用的二阶统计量对噪声不敏感,具有较好的信噪比性能;参数估计过程中,无须事先已知角度信号密度的具体类型,鲁棒性较好。仿真实验验证了所提算法的有效性。     

Pascal定理的投影证明

给出了利用中心投影证明 Pascal 定理的过程,并用较为初等的方法,导出了一些结论.     

川中金华油田大安寨段介壳灰岩储集空间演化与油气关系

金华油田位于四川盆地中部，其产层下侏罗统大安寨段介壳灰岩为滨湖高能生物介壳滩相沉积。介壳灰岩层薄、致密、非均质性强，属低孔、低渗孔隙—裂缝性储层。储集空间类型主要为次生溶蚀孔、洞、裂缝及微孔隙和微裂缝，其多期叠加即形成了独特的被致密岩体所遮挡的具有一定体积和连通范围的相对独立的储渗体圈闭，即孔隙—裂缝系统圈闭。储集空间演化分为同生—早成岩、中成岩、晚成岩和后生四个阶段，其中后两个阶段是形成油气藏的主要阶段。储集空间发育主要受成岩后生作用、构造作用等多重因素的控制。位于生油中心上倾方向早期形成的古隆起，由于来自生油岩的压释水和烃类化合物优先选择其储集空间发育的部位，并且阻碍了孔、洞、缝中次生矿物的沉淀，使储集空间得以保存，有利于油气聚集形成油气藏。