关于带常数利率与盈余相依型loss-carry-forward税收系统的Cramr-Lundberg风险模型(英文)

本文研究了带常数利率和盈余相依型loss-carry-forward税收系统的Cramr-Lundberg风险模型.利用无穷小分析方法及该过程具有的的强马氏性,得出了保险公司从开始运营到破产期间税收折现总额的数学期望表达式.作为例子,本文给出了指数分布索赔假定下该税收折现函数的具体表达式.     

滑动弧放电等离子体分解甲醇制氢

对常温常压下滑动弧放电等离子体直接分解甲醇进行了研究,探讨了载气流量、甲醇浓度、电极间距、输入电压和气化室温度等实验参数的影响。结果表明,不同操作条件导致甲醇转化率由51%升高到81.7%,氢气和一氧化碳的选择性之比基本保持一个固定值。除了氢气和一氧化碳,产物中还检测到了少量的甲烷和C₂不饱和烃以及痕量二氧化碳。不同于传统的甲醇热分解机理,提出了滑动弧放电等离子体甲醇分解的制氢路径。     

电化学分析的进展及应用

本文对2005年1月～2007年3月间我国电化学分析的发展进行了评述.文章按照电化学分析的不同领域分为极谱与伏安法,微电极、超微电极和修饰电极,离子选择性电极与传感器,示波分析法,电泳及色谱电化学,光谱电化学、电致发光法,石英晶体微天平,化学计量学方法,其他分析方法和仪器装置及实验技术等几部分.引用文献561篇.     

带负顾客和强占优先权的不耐烦信元排队

考虑带有负顾客的两类信元的强占优先权M/M/1排队系统.两类信元及负顾客的到达过程均为泊松过程.两类信元到达后分别在各自有限的缓冲器内排队,第一类信元较第二类信元有强占优先权,同时第一类信元是不耐烦的.负顾客一对一抵消队尾的第一类信元(若有),若系统中无第一类信元,到达的负顾客就自动消失.负顾客不接受服务.采用矩阵分析的方法得到了两类信元各自的稳态分布,并作了相应的性能分析.     

光纤Fizeau干涉仪的声发射检测研究

验证了一种基于光纤Fizeau干涉仪的声发射传感器,可用于固体表面传播的超声波的检测.这种传感器的特点是能够精确地检测由固体表面传播的超声波产生的微弱振动.当超声波信号通过光纤传感器到达探测器时,干涉仪的输出光强度受到了超声信号的调制.通过检测干涉仪的输出光强度并利用Fourier变换,测得了超声信号的振幅和频率.对传感系统的相位调制特性进行了仿真,并对实验结果进行了分析.     

碰撞积分中的截面数值计算

全面描述和处理了截面数值计算中所遇到的临界现象、振荡现象和积分限的截断等问题。根据用我们的方法求出的原子间相互作用势,计算了惰性气体的截面、碰撞积分和输运系数。对输运系数的计算结果与实验值进行了比较。     

电感耦合等离子体原子发射光谱法测定枸杞中11种元素含量

采用电感耦合等离子体原子发射光谱法测定了枸杞中锌、铅、锰、铁、铬、镁、钙、铜、钠、钾和镉11种元素含量。选择硝酸(2+98)溶液作为介质,选择波长为213.86,220.35,257.61,259.94,267.72,279.08,324.75,317.93,589.59,766.49,226.50 nm 11条谱线依次作为测定锌、铅、锰、铁、铬、镁、钙、铜、钠、钾和镉的分析线,测得11种元素的检出限(3δ)均低于0.07 mg·L~(-1),相对标准偏差(n=11)在0.72%～2.40%之间。比较了常规湿法消化法、高压消化罐法和微波消解法处理样品对测定结果的影响。研究表明,高压消化罐法和微波消解处理样品精密度好。     

Visible and near-infrared chiroptical gels containing electrochromic anthraquinone imide groups

A cholesterol-based organogelator bearing an anthraquinone imide(AQI) group was synthesized and characterized.It self-assembled into chiral gels in acetonitrile at low concentrations,which displayed a combination of electrochromic and chiroptical properties.Upon electrochemical reduction at -700 mV,the gel exhibited new absorption bands at around 820 nm corresponding toπ~*-π~*(SOMO→LUMO) transitions of the radical anion of AQI and strong negative Cotton effects in the same spectral region.With further reduction at -1000 mV,a new CD band with a negative Cotton effect in the range from 500 nm to 800 nm appeared concomitant with the variation of absorption spectrum.Thus, with the use of electrochromic AQI chromophore as a switch-responsive unit and the stable gel of compound N-[3β-cholest-5 -en-3-yl N-(2-aminoethyl) carbamate]anthraquinone-2,3-dicarboxylic imide as a chiral scaffold,a redox-triggered chiroptical switch operating in visible and near-infrared region was realized.     

Bogdanov-Takens bifurcation in a Leslie-Gower predator-prey model with prey harvesting

This paper discuss the cusp bifurcation of codimension 2 （i.e. Bogdanov-Takens bifurcation） in a Leslie~Gower predator-prey model with prey harvesting, which was not revealed by Zhu and Lan [Phase portraits, Hopf bifurcation and limit cycles of Leslie-Gower predator-prey systems with harvesting rates, Discrete and Continuous Dynamical Systems Series B. 14（1） （2010）, 289-306]. It is shown that there are different parameter values for which the model has a limit cycle or a homoclinic loop.     

Effect of Water Vapor Absorption on Measurements of Atmospheric Nitrate Radical by LP-DOAS

During the measurement of atmospheric nitrate radical by long-path differential optical absorption spectroscopy, water vapor strong absorption could affect the measurement of nitrate radical and detection limits of system. Under the tropospheric condition, the optical density of water vapor absorption is non-linearly dependent on column density. An effective method was developed to eliminate the effect of water vapor absorption. Reference spectra of water vapor based on the daytime atmospheric absorption spectra, when fitted together with change of cross section with water vapor column densities, gave a more accurate fitting of water vapor absorptions, thus its effect on the measurements of nitrate radical could be restricted to a minimum and detection limits of system reached 3.6 ppt. The modified method was applied during an intensive field campaign in the Pearl River Delta, China. The NO3 concentration in polluted air masses varied from 3.6 ppt to 82.5 ppt with an average level of 23.6±1.8 ppt.