最终破产概率的Lundberg上界及其应用

利用停时和鞅论技巧导出了保险公司在初始盈余为u(u≥0)的条件下的最终破产概率及其Lundberg上界,并结合实例说明它的应用.     

Seasonal variation of global stratosphere-troposphere mass exchange

By Wei formula in pressure coordinate, the stratosphere-troposphere mass exchange (STME) is diagnosed globally for 44 years from 1958 to 2001 using the European Center for Medium-Range Weather Forecasts (ECMWF) reanalysis datasets. Regions of mass flux into the stratosphere are found over Indonesia, bay of Bangladesh and the mid-west coast of South Africa. Compensating mass outflow from the stratosphere appears mainly over mid-latitudes near large-scale troughs. Upward and downward transport of mass at the middle and high latitudes accompany with each other. Mass flux into troposphere is stronger in autumn and winter than in spring and summer. Strong downward mass flux into the troposphere occurs in eastern Asia the whole year with nearly stable sites. Although the area of eastern Asia accounts for only 5.6% of that of the northern hemisphere (NH), its net mass exchange reaches 15.83% of that of the NH, which means that research on STME of eastern Asia is greatly important to that of the NH and even the global areas. Air across the tropopause enters more from stratosphere to troposphere than that from troposphere to stratosphere, which is possibly related with systematic bias of the assimilated datasets and with persistent rise of the tropopause height. Contributions of the mass exchange and the mass flux exchange in the NH and southern hemisphere (SH) on their latitudes increase from equator to pole, with larger contributions in the NH. Mass exchange and mass flux exchange per areas at high latitudes are larger than that at low latitudes, which means greater mass exchange efficiency at high latitudes.     

石刁柏三种不同类型愈伤组织扫描电镜观察

以石刁柏嫩茎为外植体诱导初始愈伤组织,以初始愈伤组织诱导胚性和非胚性愈伤组织,对3种不同类型愈伤组织进行扫描电镜观察,结果表明,3种不同类型愈伤组织在形态和结构上存在着较大的差别.     

"子"字在江西南康客家话中的特殊用法

南康客家话中的词缀"子"比起汉语普通话来在用法上更为特殊,功能上也较为丰富,其中又以用在形容词、量词及动词之后显得更为特殊一些,用在形容词之后往往带有上了"使程度降低"的附加意义;用在数量词之后则赋予了"数量减少"的附加意义;用在动词之后,根据动词的不同类型又具有了"不专注、不投入或目的性不明确或出于下意识"或"使人觉得单调、厌倦或者结果不甚明确"等附加意义.     

Evaluation of Eco-Environmental Frangibility Based on Remote Sensing and Geographic Information System

The eco-environmental frangibility is studied by choosing the factors of land use class change and vegetation cover rate, and the equation of eco-environmental frangibility and its evaluation system are established based on remote sensing （RS） and geographic information system technology （GIS）. Four different years of TM images are selected to calculate land use change grads and vegetation cover rate, and the relationship between the two factors and eco-environment frangibility index are build, taking Fuzhou as an example. The character of times change and space distribution of eco-environment frangibility are described. The result indicates the area of eco-environment frangibility increased 2.6% in Fuzhou during twelve years, and expands from the region between infield and forest land to forest land in space distribution.     

Density functional theory study on the insertion reaction mechanism of dibromocarbene with formaldehyde

The insertion reaction mechanism of CBr2 with CH3CH2O has been studied by using the B3LYP/6-311G(d) and CCSD(T)/6-311G(d) at single point. The geometries of reactions,transition state and products were completely optimized. All the transition state is verified by the vibrational analysis and the internal re-action coordinate (IRC) calculations. The results show that reaction (1) is the dominant reaction path,which proceeds via two steps: i) two reactants form an intermediate (IM1),which is an exothermal re-action of 8.62 kJ·mol?1 without energy barrier; ii) P1 is obtained via the TS1 and the H-shift,in which the energy barrier is 44.53 kJ·mol?1. The statistical thermodynamics and Eyring transition state theory with Wigner correction are used to study the thermodynamic and kinetic characters of this reaction in temperature range from 100 to 2200 K. The results show that the appropriate reaction temperature ranges from 200 to 1900 K at 1.0 atm,in which the reaction has a bigger spontaneity capability,equi-librium constant (K) and higher rate constant (k).     

西秦岭厂坝-李家沟铅锌矿矿床地质特征和成因分析

摘要：厂坝一李家沟矿床规模巨大，是秦岭地区西成铅锌成矿带的重要矿床之一。矿体形态和规模明显受沉积洼地控制。矿石常显微莓球状、针状、他形隐晶质、显微球粒结构。可识别的矿石沉积一成矿作用构造有浸染一条带状、条纹一条带状、隐晶质条带、条块状、块状构造等。矿体中下部主要为块状矿石，富黄铁矿、闪锌矿、钠长石和石英；上部为条带状、浸染状和层纹状矿石，富闪锌矿、重晶石和方解石。条带状的石英钠长石岩和重晶石所含的典型喷气元素B和As的含量比正常沉积岩高出几倍到几十倍。闪锌矿中Zn／Cd〉〉500，黄铁矿中Co／Ni为O．2～O．8。另外，该矿主要形成于受裂谷控制的克拉通内部及其边缘的沉降盆地。结果表明，厂坝矿具有较典型的Sedex型矿床特征。[第一段]     

重组抑肽酶的表达纯化和活性测定

抑肽酶是一种用途广泛的丝氨酸蛋白酶抑制剂.用基因重组技术将化学合成的抑肽酶基因插入表达载体pET28a,并转化至大肠杆菌Rosetta(DE3)中,经IPTG诱导后,表达产物以包涵体形式存在于菌体内包涵体纯化后经复性及CM-阳离子交换层析后,从每升培养液可获得2.4 mg抑肽酶,纯度可达90%.活性测定结果显示,重组抑肽酶可竞争性抑制纤溶酶对小分子底物S2251的水解活性.抑制常数(Ki)为(0.6±0.3)nmol/L,与天然抑肽酶的抑制活性相似.     

曲韵研究的回顾与展望

曲韵研究是传统音韵学与传统戏曲学、音乐学三学科相互交叉的一个新兴研究领域。语音史研究者的曲韵研究可推动近代汉语语音研究的发展,他们对曲韵的考察从20世纪上半期开始,20世纪下半期打破了过去韵书研究的单一局面,更多地从曲韵实际进行探索,学界已逐渐总结出一套成熟可行的研究方法。展望曲韵研究的未来,有许多反映曲韵实际的材料尚待挖掘,可以尝试新的研究思路,拓宽研究视野。将语音史背景下的曲韵研究与文学史、音乐史背景下的曲韵研究有机地结合起来,应是研究者未来需要关注的焦点。     

"数字国土"框架下的国土政务信息化平台建设初探

介绍了"数字国土"工程的基本内容,在此基础上提出了"数字国土"工程建设的4个关键步骤.针对目前的现状和国内数字国土发展的实际,对国土政务信息化平台建设这一当前亟待解决的环节进行探讨,提出了国土政务信息化平台建设的总体设计方案.