Study on tribological behaviors of short glass fiber and polytetrafluoroethylene reinforced polycarbonate composites via a d‐optimal mixture design

This study analyzed variations of tribological behaviors that depend on the injection molding techniques during the blending of short glass fiber (SGF) and polytetrafluoroethylene (PTFE) reinforced polycarbonate (PC) composites. The proposed planning of blending experiments is to use a D‐optimal mixture design (DMD). The tribological behaviors of friction coefficient and wear mass loss were selected for discussion. Nine experimental runs, based on a DMD method, utilized to train the back‐propagation neural network (BPNN) and then the simulated annealing algorithm (SAA) approach is applied to search for an optimal mixture ratio setting. In addition, the result of BPNN integrating SAA was also compared with response surface methodology (RSM) approach. The results of confirmation experiment show that DMD, RSM, and BPNN integrating SAA method are effective tools for the optimization of reinforced process. Furthermore, the scanning electron microscope (SEM) images show that the abundant debris are peeled off from the matrix materials and predominant delamination mechanisms and plastic deformation are shown on the worn surface after tribological behavior tests. Copyright © 2010 John Wiley & Sons, Ltd.     

Lanostane-type triterpenoids from Diospyros discolor

Four new lanostane-type triterpenes, 24-ethyl-3beta-methoxylanost-9(11)-en-25-ol (1), 3beta-methoxy-24-methylenelanost-9(11)-en-25-ol (2), 3beta-methoxy-25-methyl-24-methylenelanost-9(11)-en-21-ol (3) and 3beta-methoxy-24-methyllanosta-9(11),25-dien-24-ol (4) together with three known triterpenes, betulinaldehyde, betulinic acid methyl ester, and ursaldehyde have been isolated from the methanol extract of the twigs of Diospyros discolor. The structures of those new compounds were elucidated by spectroscopic methods.     

Choosing best alliance partners and allocating optimal alliance resources using the fuzzy multi-objective dummy programming model

Synergy effects are the motives to enter into strategic alliances; however due to lack of adequate preparation or planning, these alliances often fail. It is of no doubt that a successful strategic alliance depends on choosing the correct alliance partners and appropriate resource allocation. In this paper, the fuzzy multi-objective dummy programming model is proposed to overcome the above-mentioned problems. Two types of strategic alliances, joint ventures and mergers and acquisitions (M&A), are demonstrated to choose the best alliance partners and allocate the optimal alliance resources in a numerical example. Based on the results, our method can provide the optimal alliance cluster and satisfaction in strategic alliances.     

Modeling single-frequency laser-plasma acceleration usingparticle-in-cell simulations: the physics of beam breakup

We investigate electron acceleration from space-charge waves driven by single-frequency lasers using a fully explicit particle-in-cell (PIC) model. The two dimensional (2-D) simulations model ~100 fs pulses at densities near n=4×10¹⁹ cm^-3 for 1-μm lasers. The pulses are found to break up due to a combination of longitudinal and transverse bunching of the laser intensity via Raman forward scattering type instabilities. The ponderomotive force of these intensity modulations generates large amplitude plasma waves. Large numbers of self-trapped electrons and multiple Raman forward scattering satellites are observed. The relevance of these simulations to experiments is discussed     

A Public-Key Traitor Tracing Scheme with Revocation Using Dynamic Shares

We proposed a new public-key traitor tracing scheme with revocation capability using dynamic shares and entity revocation techniques. Our schemes traitor tracing and revocation programs cohere tightly. The size of the enabling block of our scheme is independent of the number of receivers. Each receiver holds one decryption key only. The distinct feature of our scheme is that when traitors are found, we can revoke their private keys (up to some threshold z) without updating the private keys of other receivers. In particular, no revocation messages are broadcast and all receivers do nothing. Previously proposed revocation schemes need update existing keys and entail large amount of broadcast messages. Our traitor tracing algorithm works in a black-box way. It is conceptually simple and fully k-resilient, that is, it can find all traitors if the number of them is k or less. The encryption algorithm of our scheme is semantically secure assuming that the decisional Diffie-Hellman problem is hard.AMS Classification: 11T71, 68P30     

On the optimal product mix in life insurance companies using conditional value at risk

This paper proposes a Conditional Value-at-Risk Minimization (CVaRM) approach to optimize an insurer’s product mix. By incorporating the natural hedging strategy of Cox and Lin (2007) and the two-factor stochastic mortality model of Cairns et al. (2006b), we calculate an optimize product mix for insurance companies to hedge against the systematic mortality risk under parameter uncertainty. To reflect the importance of required profit, we further integrate the premium loading of systematic risk. We compare the hedging results to those using the duration match method of Wang et al. (forthcoming), and show that the proposed CVaRM approach has a narrower quantile of loss distribution after hedging—thereby effectively reducing systematic mortality risk for life insurance companies.     

Mass-analyzed Threshold Ionization Spectroscopy of Rotamers of p-ethoxyphenol Cations and Configuration Effect

利用双色双光子质量分辨的阈值电离光谱技术,研究了对位乙氧基苯酚顺式和反式两种构型的离子态振动特性. 测得顺式和反式精确的绝热电离势分别为61565±5和61670±5 cm^-1. 与对位甲氧基苯酚实验结果比较,顺式和反式的测得的绝热电离势分别降低了645和643 cm^-1. 从所得到的两种构型的高分辨离子态光谱中,可知顺式和反式不同构型对苯环平面的振动影响很小,而低频率的C-OC₂H₅弯曲振动在两种构型中都很活跃.