La(OH)3凝聚的形态和粒径分布研究

在形态空间中对La(OH)_3凝聚体系统的形态分布进行了描述。在此基础上, 对La(OH)_3凝聚体的粒径分布进行了模拟, 进而提出了La(OH)_3凝聚体的形成机制。     

基于不同竞争状况的威斯通并购估价模型研究

本文首先根据收益增长率等于再投资额与再投资收益率的乘积这一基本结论,对超常增长而后无增长的威斯通模型作了一点修正;接着分析了该模型中隐含的企业总投资资本利润率;最后根据微观经济学理论探讨了企业在无增长阶段可能面临的不同竞争状况对其未来盈利能力和现金流的影响,建立了更具普遍性的估价模型.     

带利息力和干扰的批量索赔一般到达风险模型

本文在经典风险模型的基础上,将索赔到达过程推广为更新过程,索赔可以批量到达,且带有常数利息力和Brown运动干扰项,得到一个新的风险模型,运用Markov骨架过程的方法,得出盈余过程的瞬时分布和生存概率.     

Solid-state 13C NMR characterization of molecular orientation of hot drawn nylon 6

Two-dimensional cross polarization (CP), magic angle spinning (MAS) rotor synchronization NMR spectroscopy has been used to determine quantitatively the molecular orientational distribution function on hot-drawn Nylon 6. Both films and fibers are studied that had been thermally deformed at temperature above T_g, from 60 to 175°C at draw ratios in the range of 1-5.5. In the two-dimensional NMR spectrum, the sidebands that intrinsically originate from the chemical shift anisotropy reveal the degree of molecular orientational order. No preferential orientational order is detected for the sample without thermal deformation, and the highest degree of order is observed for samples which have been hot drawn above T_g at ratios ca. 5. Based on the aggregate model the maximum achievable order parameters are determined. © 1994 John Wiley & Sons, Inc.     

一类新的表面活性剂——长链烷基三苯基鏻——Ⅵ.稳态荧光猝灭法测定十二烷基三苯基溴化鏻胶束的平均簇集数

研究了十二烷基三苯基溴化鏻(C_(12)PBr)胶束中N,N-二甲基苯胺(DMA)和二苯甲酮(DPK)对芘的荧光猝灭,发现DMA的猝灭行为不符合Stern-Volmer动态猝灭和Turro静态猝灭模型;DPK的猝灭行为不符合Stern-Volmer猝灭模型,但遵从Turro静态猝灭模型。根据DPK的静态猝灭性质测得C_(12)PBr胶束的平均簇集数为15士2,并相应地得到C_(12)PBr的临界胶束浓度为(1.77±0.09)×10~(-3)mol/L,后者与文献值一致。     

Photoionization processes in F aggregate centres of LiF crystal

Extensive studies have been carried out on the optical conversion of F and F-aggregate colour centres produced in lithium fluoride single crystal on gamma irradiation. Using 308 nm XeCl laser it has been shown that significantly large population build-up of F ₃ ⁺ centre and reduction in the population of undesirable F₂ centres can be achieved in gamma irradiated crystal at room temperature due to multistep photoionization processes. These and other investigations have provided a scheme for possible laser action based on F ₃ ⁺ colour centres in LiF crystal at room temperature.     

Multi-Armed bandit problem revisited

In this paper, we revisit aspects of the multi-armed bandit problem in the earlier work (Ref. 1). An alternative proof of the optimality of the Gittins index rule is derived under the discounted reward criterion. The proof does not involve an explicit use of the interchange argument. The ideas of the proof are extended to derive the asymptotic optimality of the index rule under the average reward criterion. Problems involving superprocesses and arm-acquiring bandits are also reexamined. The properties of an optimal policy for an arm-acquiring bandit are discussed.This research was supported by NSF Grant IRI-91-20074.     

Zero-sum stochastic games with unbounded costs: Discounted and average cost cases

Zero-sum stochastic games with countable state space and with finitely many moves available to each player in a given state are treated. As a function of the current state and the moves chosen, player I incurs a nonnegative cost and player II receives this as a reward. For both the discounted and average cost cases, assumptions are given for the game to have a finite value and for the existence of an optimal randomized stationary strategy pair. In the average cost case, the assumptions generalize those given in Sennott (1993) for the case of a Markov decision chain. Theorems of Hoffman and Karp (1966) and Nowak (1992) are obtained as corollaries. Sufficient conditions are given for the assumptions to hold. A flow control example illustrates the results.     

Linear complementarity and discounted switching controller stochastic games

The class of discounted switching controller stochastic games can be solved in one step by a linear complementarity program (LCP). Following the proof of this technical result is a discussion of a special formulation and initialization of a standard LCP pivoting algorithm which has, in numerical experiments, always terminated in a complementary solution. That the LCP algorithm as formulated always finds a complementary solution has not yet been proven, but these theoretical and experimental results have the potential to provide an alternative proof of the ordered field property for these games. Numerical experimentation with the reformulated LCP is reviewed.     

纳米混合分子聚集体材料中弗兰克尔激子迁移的相位弛豫

在有机染料ＰＩＣ－１中引入其衍生物ａｚａＰＩＣ－Ｉ形成能量势垒，改变在混合分子聚集体中ＰＩＣ－Ｉ的Ｊ－聚集体的实体长度。用双调制外差检测的累积光子回波技术研究了相干弗兰克尔激子失相过程。观测到激子失相时间Ｔ２随ａｚａＰＩＣ－１克分子数的增大从６０ｐｓ变为２２４ｐｓ。