基于不确定控制理论的最优策略研究

本文在不确定理论的框架下,研究一类带背景状态变量的最优控制模型.在乐观值准则下,利用不确定动态规划的方法,证明了不确定最优性原则,得到最优性方程.作为应用,求解一个固定缴费(DC)型养老金的最优投资策略问题,在乐观值准则下,以工资变量为背景状态变量,建立养老金模型.通过求解不确定最优性方程得到最优投资策略和最优支付率.     

Allocating unfunded liability in pension valuation under uncertainty

This paper studied the cost allocation for the unfunded liability in a defined benefit pension scheme incorporating the stochastic phenomenon of its returns. In the recent literature represented by Cairns and Parker [Insurance: Mathematics and Economics 21 (1997) 43], Haberman [Insurance: Mathematics and Economics 11 (1992) 179; Insurance: Mathematics and Economics 13 (1993) 45; Insurance: Mathematics and Economics 14 (1994) 219; Insurance: Mathematics and Economics 14 (1997) 127], Owadally and Haberman [North American Actuarial Journal 3 (1999) 105], the fund level is modeled based on the plan dynamics and the returns are generated through several stochastic processes to reflect the current realistic economic perspective to see how the contribution changed as the cost allocation period increased. In this study, we generalize the previous constant value assumption in cost amortization by modeling the returns and valuation rates simultaneously. Taylor series expansion is employed to approximate the unconditional and conditional moments of the plan contribution and fund level. Hence the stability of the plan contribution and the fund size under different allocation periods could be estimated, which provide valuable information adding to the previous works.     

Dependence of the rate constants on the treatment of internal rotation modes: the reaction OH + CH3SH --> CH3S + H2O as an example

The title reaction has been used as an example to test the importance of using a hindered rotor treatment instead of a harmonic oscillator model for calculating vibrational partition functions corresponding to low-frequency internal rotation modes. First, a normal-mode analysis according to the Ayala and Schlegel's algorithm has been used to identify the internal rotation modes of methanethiol and the transition state structure. Then, after calculation of the energy barrier for each internal rotation, the corresponding hindered rotor partition functions have been calculated following the CW scheme of Chuang and Truhlar. The results show that the anharmonic treatment produces a rather modest improvement of the rate constants at room temperature or below.     

Excess enthalpies of ethylbenzene + alkane systems at 25°C. An interpretation in terms of the Prigogine-Flory-Patterson model

The molar excess enthalpies for the ethylbenzene + n-decane and ethylbenzene + n-tetradecane systems have been measured at 25°C over the complete concentration range. These results and others from the literature for alkanes + ethylbenzene, and alkanes + toluene have been discussed in terms of the Prigogine-Flory-Patterson theory.     

Synthesis of protected peptides from the human IgG1 hinge region on PEG support using disulfide bond synthons and alkaline or enzymatic detachment

Peptides from the hinge region of human IgG1 are potential defined carriers of synthetic immunogens. Their synthesis was carried out on the soluble support—PEG-OMe 2000 using disulfide bond synthons. The loading capacity of the polymer was increased twofold by anchoring the lysine as a simple branching unit. The amino acid leucine was used as an enzymatically cleavable linker. Peptide detachment from the polymer was performed either by classical ester bond saponification or newly by peptide bond cleavage catalyzed by thermolysin in water.     

出租车司机社会贡献评价方法研究

出租车司机的社会贡献对于促进城市经济发展和社会进步具有重要的作用,评价出租车司机的社会贡献是激励出租车司机多做社会贡献的重要手段。为了评价出租车司机的社会贡献,本文提出了一种基于实际出租车运营数据的评价方法。本文设计了运营特性、重点区域、恶劣天气、大事件四个体现司机社会贡献的指标,以此构建了出租车司机社会贡献评价指标体系,进而选用了主观赋权法G1法和客观赋权法拉开档次法相结合的赋权方式对指标赋权,并选择四种评价信息集结方法建立了出租车司机社会贡献评价模型。最后,通过实际的出租车运营数据验证了本方法的可行性。本文为评价出租车司机社会贡献提供了一种研究思路和方法,并对政府政策的制定和企业策略的实施具有一定的启示。     

ELASTIC BEHAVIOR OF PROTEIN-LIKE SINGLE CHAIN

The conformational properties and elastic behaviors of protein-like single chains in the process of tensile elongation were investigated by means of Monte Carlo method. The sequences of protein-like single chains contain two types of residues: hydrophobic (H) and hydrophilic (P). The average conformations and thermodynamics statistical properties of protein-like single chains with various elongation ratio λ were calculated. It was found that the mean-square end-to-end distance r increases with elongation ratio,λ. The tensor eigenvalues ratio of : decreases with elongation ratio λ for short (HP)x protein-like polymers, however, the ratio of : increases with elongation ratioλ,especially for long (H)x sequence. Average energy per bond increases with elongation ratioλ, especially for(H)x protein-like single chains. Helmholtz free energy per bond also increases with elongation ratioλ. Elastic force (f), energy contribution to force (fU) and entropy contribution to force (fs) for different protein-like single chains were also calculated.These investigations may provide some insights into elastic behaviors of proteins.     

Heat Capacities of Aqueous Solutions of Acetone; 2,5-Hexanedione; Diethyl Ether; 1,2-Dimethoxyethane; Benzyl Alcohol; and Cyclohexanol at Temperatures to 523 K

The heat capacities of aqueous solutions of acetone, 2,5-hexanedione, diethyl ether, 1,2-dimethoxyethane, benzyl alcohol and cyclohexanol at concentrations of 0.1 to 1.0 mol⋅kg⁻¹ were determined at temperatures of 298.15, 423.15, 473.15 and 523.15 K and pressures up to 28 MPa. The measurements were performed at ambient conditions using the commercial Picker differential flow calorimeter and at high temperatures and pressures with a customized Picker type calorimeter constructed at the Blaise Pascal University, Clermont-Ferrand. Standard molar heat capacities were obtained by weighted extrapolation to the infinite dilution limit. The contributions of –CO–, –O– and –OH groups to the standard molar volume and standard molar heat capacity were determined from the newly determined and literature data. The variation of the three oxygen-containing group contributions with temperature and molecular structure is examined qualitatively.     

GC／MS检测信息的综合利用

从充分利用气相色谱／质谱（ＧＣ／ＭＳ）提供的信息来鉴定ＧＣ流出组分的目的出发，并以脂肪醇分析为例讨论了ＧＣ保留指数在ＭＳ谱图解析及ＭＳ鉴定结果的合理性检验方面的作用。总结了ＧＣ保留的同系物规律、极性规律、加和规律及异构物规律来指导ＭＳ谱图解析。提出了含氧化合物官能团相对于－ＣＨ２－质量数的保留指数附加贡献值辅助ＭＳ确定化合物的类别。同时采用了ＧＣ／ＭＳ中选择离子检测方法（ＳＩＭ）在分子离子峰受噪音干扰或太弱以至完全未观测到时来进一步佐证其相对分子质量。     

Apparent molal volumes of aqueous solutions of bis-tetraalkylammonium salts at 25°C: Methylene-group contribution to the limiting molal volume

Densities of aqueous solutions of a series of polymethonium chloride and bromide salts (CH₃)₃–N–(CH₂)_n–N–(CH₃)₃X₂ have been measured at 25°C. Apparent molal volumes have been calculated, and methylene-group contributions to the limiting apparent molal volumes °_v have been estimated. Constant values of the methylene-group contribution of 16.5 and 17.0 cm³-mole^–1 were obtained for the bromide and chloride salts, respectively. These values are consistent with methylene-group contributions reported for other series of organic electrolytes.