Local influence analysis for semiparametric reproductive dispersion nonlinear models

The present paper proposes a semiparametric reproductive dispersion nonlinear model (SRDNM) which is an extension of the nonlinear reproductive dispersion models and the semiparameter regression models. Maximum penalized likelihood estimates (MPLEs) of unknown parameters and nonparametric functions in SRDNM are presented. Assessment of local influence for various perturbation schemes are investigated. Some local influence diagnostics are given. A simulation study and a real example are used to illustrate the proposed methodologies.     

Optimal dividend and dynamic reinsurance strategies with capital injections and proportional costs

We consider an optimization problem of an insurance company in the diffusion setting, which controls the dividends payout as well as the capital injections. To maximize the cumulative expected discounted dividends minus the penalized discounted capital injections until the ruin time, there is a possibility of (cheap or non-cheap) proportional reinsurance. We solve the control problems by constructing two categories of suboptimal models, one without capital injections and one with no bankruptcy by capital injection. Then we derive the explicit solutions for the value function and totally characterize the optimal strategies. Particularly, for cheap reinsurance, they are the same as those in the model of no bankruptcy.     

The risks and returns of stock investment in a financial market

The risks and returns of stock investment are discussed via numerically simulating the mean escape time and the probability density function of stock price returns in the modified Heston model with time delay. Through analyzing the effects of delay time and initial position on the risks and returns of stock investment, the results indicate that: (i) There is an optimal delay time matching minimal risks of stock investment, maximal average stock price returns and strongest stability of stock price returns for strong elasticity of demand of stocks (EDS), but the opposite results for weak EDS; (ii) The increment of initial position recedes the risks of stock investment, strengthens the average stock price returns and enhances stability of stock price returns. Finally, the probability density function of stock price returns and the probability density function of volatility and the correlation function of stock price returns are compared with other literatures. In addition, good agreements are found between them.     

痂囊腔菌素A分子构型和分子内氢键的理论研究

用半经验量子化学AM1方法对天然苝醌化合物痂囊腔菌素A(EA)的分子构型和分子内氢键进行了研究;从EA可能的64种构型中选择16种进行了计算.结果表明,EA的X射线晶体结构对应的构型是II型左旋(A)a,a型(II-L-A-a,a);小的生成热差值可以使得异构体间的转换容易进行,有利于发生分子内质子传递.尽管采用AM1方法计算得到的EA各种构象的平面性有所差别,但都很接近晶体的平面性.此外,EA分子内氢键键能的平均值为22.9kJ/mol;II型的氢键键能比I型的大,(9,10)位的氢键键能比(3,4)位的大;EA的平面性是由苝醌环上的侧链取代所决定,而与分子内是否存在氢键无关.     

二维气相色谱技术及其在烟草行业中的应用

二维气相色谱的应用大大提高了分析能力，而与飞行时间质谱的联用更使其达到一个新的高度。介绍了二维气相色谱的原理、优越性及不足，以及与飞行时间质谱联用的技术进展。综述了近年来该技术在各行业特别在烟草行业中的应用，展望了二维气相色谱在烟草行业中的应用前景。     

Effects of non-Gaussian noise on a calcium oscillation system

We investigate the effects of the non-Gaussian colored noise on a calcium oscillation system using stochastic simulation methods. It is found that the reciprocal coefficient of variance R has a maximum (R max ) with increasing noise intensity Q. The non-Gaussian noise parameter q has an important effect on the system. For some values of q (e.g., q = 0.9, q = 1.0), R has a maximum with increasing correlation time τ. Non-Gaussian noise induced spikes are more regular than Gaussian noise induced spikes when q is small and Q has large values. The R has a maximum with increasing q. Therefore, non-Gaussian noise could play more effective roles in the calcium oscillation system.     

氮杂Brazilin/二芳基茚杂合物的合成研究

天然产物在药物化学中具有非常重要的地位,天然产物杂合物的设计合成,可以为药物筛选提供数目更多、结构更多样化的生物活性分子,是发现更多的新药先导化合物的一条非常重要的途径.以邻苯二甲醚为原料,经傅克酰基化、酮酯缩合、Knoevenagel缩合、Nazarov环化、酮酸酯的胺解、1,3-二羰基化合物的α-羟基化、酮羰基和酰胺的还原及分子内的傅克环化共9步反应,合成了氮杂brazilin(Aza-brazilin)与1,3-二芳基茚类化合物的一个杂合物.     

Evans手性助剂控制的不对称Michael加成立体选择性研究(Ⅱ)

手性助剂控制的不对称反应是不对称合成的重要方法之一.以Evans手性助剂控制的Michael受体1为底物,在FeCl3催化下,通过不同格式试剂对其进行Michael加成,一步反应得到了一系列含两个手性中心的Michael加成产物2a～2h.获得了较高的立体选择性,其中化合物2d和2e得到了de值高达98%的非对映选择性.研究结果表明,亲核试剂的空间位阻是影响产物立体选择性的主要因素.     

Low temperature testing and neutron irradiation of a swept charge device on board the HXMT satellite

We present the low temperature testing of an SCD detector, investigating its performance such as readout noise, energy resolution at 5.9 keV and dark current. The SCD's performance is closely related to temperature, and the temperature range of -80 ℃ to -50 ℃ is the best choice, where the FWHM at 5.9 keV is about 130 eV. The influence of the neutron irradiation from an electrostatic accelerator with fluence up to 1×10⁹ cm^-2 has been examined. We find the SCD is not vulnerable to neutron irradiation. The detailed operations of the SCD and the test results of low temperature are reported, and the results of neutron irradiation are discussed.     

Decomposition of Insoluble and Hard-to-Degrade Animal Proteins by Enzyme E77 and Its Potential Applications

Insoluble and hard-to-degrade animal proteins are group of troublesome proteins, such as collagen, elastin, keratin, and prion proteins that are largely generated by the meat industry and ultimately converted to industrial wastes. We analyzed the ability of the abnormal prion protein-degrading enzyme E77 to degrade insoluble and hard-to-degrade animal proteins including keratin, collagen, and elastin. The results indicate that E77 has a much higher keratinolytic activity than proteinase K and subtilisin. Maximal E77 keratinolytic activity was observed at pH 12.0 and 65 °C. E77 was also adsorbed by keratin in a pH-independent manner. E77 showed lower collagenolytic and elastinolytic specificities than proteinase K and subtilisin. Moreover, E77 treatment did not damage collagens in ovine small intestines but did almost completely remove the muscles. We consider that E77 has the potential ability for application in the processing of animal feedstuffs and sausages.