热障涂层厚度及其涂敷下材料内部缺陷的红外定量识别

针对热障涂层结构材料红外定量检测存在的不足,提出基于脉冲相位的LM(LevenbergMarquardt)识别算法。针对研究问题,建立了轴对称圆柱坐标下热障涂层结构材料的瞬态导热模型,利用有限体积法计算出检测表面的温度场,经快速傅里叶变换得到检测表面的相位分布,分析待检测参数对检测表面相位差的影响。以相位为识别条件,采用LM反演算法对热障涂层厚度及其涂敷下材料内部缺陷位置大小进行定量识别,并采用数值实验方法验证了基于相位的LM识别方法的有效性。     

铝合金隔热涂层研究

本工作研究了在ＬＹ１２表面用等离子喷涂氧化锆隔热涂层的热传导性能和抗热震性能及气孔率对这些性能的影响。结果表明,在所选择的最佳工艺参数和厚度下,涂层具有良好的绝热性和抗热震性。     

微分对策界栅理论在舰艇作战能力评估中的应用

作战能力是表征战斗舰艇战术技术性能的一项重要指标,如何正确评价舰艇的作战能力一直是军事运筹研究的热点.利用定性微分对策的界栅理论研究了一类作战问题,通过构造捕获区面积和咽喉区域面积,并以此作为动态评估舰艇作战能力的衡量指标.研究结果可为综合评价舰艇作战能力提供一条新途径.     

陶瓷/金属梯度热障涂层的制备及性能评价

为了评价陶瓷/金属梯度热障涂层的性能,设计了4种涂层方案和2种基体材料(1Cr18Ni9Ti和2Cr13).利用单枪单送粉器成功地制备了线性梯度涂层.通过观察涂层的微观结构、测量涂层的抗热震性能和热残余应力来评价涂层的性能.利用扫描电镜对各种陶瓷涂层的微观结构进行了观察和分析,利用X射线能谱分析得到了陶瓷梯度涂层试样中的不同区域的衍射图.热震试验表明,梯度涂层比非梯度涂层具有更好的抗热震性能.采用钻孔法对不同涂层方案进行了残余应力的测量,结果表明,压应力出现在1Cr18Ni9Ti基体材料上,而拉应力出现在2Cr13基体材料上.     

基于非合作博弈的栅栏信息覆盖虚拟节点组合算法

邻近节点通过协作感知和信息融合组成虚拟节点,能够增加信息覆盖栅栏长度.基于非合作博弈模型,设计了一种完全分布式的虚拟节点组合算法DVSF算法.DVSF算法面向栅栏信息覆盖应用,以尽量增加整个网络的信息覆盖栅栏长度为目标,将合适的邻近节点组合成虚拟节点,提升了整个网络的栅栏信息覆盖性能.仿真实验验证了DVSF算法的有效性...     

倒向随机微分方程在欧式期权中的应用

假设市场为无套利市场,而且市场上只有两种证券:一种是无风险债券;一种是有风险的股票。通过自筹资策略,得到期权价格所满足的倒向随机微分方程(BSDE),利用倒向随机微分方程给出欧式期权价格概率表示;并证明欧式期权的完全套期保值性。     

太阳风作用下航天器表面充电效应分析

针对太阳风等离子体中航天器的充电过程,基于欧洲航天局开发的航天器表面充电仿真软件,建立了航天器的数值计算模型,模拟了太阳风等离子体与航天器的相互作用,实现了不同表面材料时航天器表面电位以及尾迹结构的计算分析,给出了近日环境下航天器周围的空间电位结构以及等离子体密度分布情况。研究结果表明:表面材料的选择将影响空间势垒深度以及尾迹结构,表面充电至更低电位的表面材料具有较小尾迹区域;航天器向阳面电位分布主要由光电子以及二次电子主导,而背阳面的电位分布则主要受到尾迹效应的影响。以上结果对太阳风环境航天器探测和评估等相关工作以及工程研究具有一定的理论参考价值。     

核裂变过程动态模拟计算的动力学系数

本文利用(c,h,a)三参数旋转体模型计算了形变核的相对表面能、相对库仑能及相对转动能。这些相对能量与具体核无关,具有普适性,可以用于核裂变动态过程的模拟计算。利用这些结果,计算了一些核的形变位能随三参数变化的情况,给出了裂变位垒高度,与实验结果符合较好。对~(236)U的形变位能曲面作了较详细的分析,得出一些有益的结论。用Werner—Wheeler方法计算了形变核的惯性质量和粘滞张量随三参数变化情况,对断点线方程作了深入讨论,为核裂变动态过程的计算机模拟准备了必要的系数。     

A Bayesian analysis on the effect of multiple supply options in a quick response environment

In the apparel industry, vendors often suffer from high mismatches in supply and demand. To cope with this problem, they procure the same style product from different suppliers with different manufacturing costs. Especially in the quick response environment, which allows vendors to monitor trends in customer demand and search for available suppliers through the electronic market, they have additional opportunities to improve their decision‐making. In this paper, we propose an analytical profit maximization model and develop efficient decision tools to help both the middle and lower level managers pursuing this strategy. Furthermore, we have shown how significantly the vendors' potential competitive edge can be improved by exploiting multiple supply options, even at the expense of high premium procurement costs for late orders. The effect is critical, especially in a highly competitive market, and it has important implications for the top managers. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2003     

On fair designs of cross-chain exchange for cryptocurrencies via Monte Carlo simulation

Cryptocurrency is one of the earliest and the most successful applications of blockchain, and it utilizes the distributed ledger, which is a commonly used technique in blockchain, to make a decentralized transaction within the blockchain of a cryptocurrency. However, how to make a decentralized transaction of cryptocurrencies between parties on different blockchains, that is, the cross-chain exchange, is not well-studied. In this paper, we develop a new method to make cross-chain exchanges based on the classical atomic swap. We first study the optionality embedded into the atomic swap and propose to add a premium into the atomic swap, and then design a new procedure with the premium to guarantee the fairness of the cross-chain exchange. We also provide an algorithm based on the least-squares Monte Carlo method to estimate the premium and analyze the convergence of the algorithm. Moreover, we study the cross-chain exchange with margin trading. We propose an adapted exchange procedure to make a fair cross-chain exchange and an algorithm to estimate the fair premium under the margin trading. Numerical experiments are provided to show the effectiveness of the algorithms.