Mathematical modeling and solution trajectories of complex chemical mechanism based on Monte Carlo methods

The main purpose of this article is introducing the method of Spectral Quasi Equilibrium Manifold taking different model, simple and complex mechanism to find solution curve. Before that discussing reaction kinetic, reduction of system, chemical equilibrium, QEM technique. As in complex reaction we need to split reaction mechanism in different route to reduce the complexity of higher dimensional system.in this article SQEM technique is apply to different route and comparison of route is also discussed. In previous years, the depiction of existing method based on chemical reaction kinetics has become a standard approach, for which estimation of involved parameters become challenge. For the model developments and standardization, Sensitivity analysis is powerful tool. Influence of parameters on target output is discussed through graphical results.     

最小Hamilton回路是最优旅行商路线的条件

本文给出并证明了一个非完全图 G的最小 Hamilton回路必为最优旅行商路线的条件是除了应满足广义三角不等式外 ,还必须满足正则收缩性     

Hydrodynamic limit of the Robinson–Schensted–Knuth algorithm

We investigate the evolution in time of the position of a fixed number in the insertion tableau when the Robinson–Schensted–Knuth algorithm is applied to a sequence of random numbers. When the length of the sequence tends to infinity, a typical trajectory after scaling converges uniformly in probability to some deterministic curve.     

关于旅游路线规划问题的建模与研究

近年来,随着我国国民经济的快速发展和人们生活水平的提升,自驾游在全国旅游业中的比重逐渐增大.以旅游爱好者常住地——西安市为例,采用分步优化、聚类分析、蚁群优化算法、0-1规划、层次分析等数学方法,使得游览全国201个5A级景点的时间最短、费用最低、旅游体验度最优.     

PYRIDINATION OF POLY（VINYL CHLORIDE） via A HOMOLYTIC PATHWAY

PVC was subjected to a chemical modification aiming at replacing the chlorine atoms by pyridine groups via a homolytic route. Pyridine groups were peculiarly affixed to the PVC matrix via a carbon-carbon bond rather than a carbon-nitrogen one. PVC was first iodinated using the Conant-Finkelstein reaction, followed by the application of the homolytic conditions of Minisci to generate pyridinated PVC with a varying degree of substitution. The extent of substitution was not high; the reaction on 30% iodinated PVC afforded a degree of modification no greater than 3%.     

图论在传送网工程设计中的应用探讨

利用运用图论理论这一数学工具,对传送网环网工程设计中光缆路由和业务承载问题进行了分析,通过数学建模,提出了相应的解决方法.在理论总结的基础上,结合工程实例提供了定量分析.     

最优路径搜索压缩感知水声通信信道估计

将信号恢复中最优路径搜索的A*正交匹配追踪(A*Orthogonal Matching Pursuit,A*OMP)伪贪婪算法引入到水声通信信道估计中,可以有效改善正交匹配追踪(OMP)算法容易陷入局部最优的问题,并提出了一种改进型的A*OMP水声信道估计算法。改进了路径初始化方式,同时为了避免过多迭代引起的未知误差,将前后两次迭代残差之差作为停止准则。在正交频分复用(OFDM)通信体制下,对OMP、A*OMP和本文改进方法的估计误差和误比特率进行了仿真对比,随着信噪比的增加,改进方法未出现误差平台,且受导频间隔影响较小。仿真结果表明相对于OMP算法和传统A*OMP算法,在高信噪比下改进方法的估计误差分别降低约2和1个数量级,海试数据结果验证了改进方法的可行性,其误比特率分别平均降低42.0%和4.7%。     

Mesoporous Mn promoted Co3O4 oxides as an efficient and stable catalyst for low temperature oxidation of CO

Mesoporous Mn-doped Co₃O₄ catalysts were successfully prepared via a dry soft reactive grinding method based on solid state reaction, and their catalytic performances on CO oxidation were evaluated at a high space velocity of 49,500 mL g⁻¹ h⁻¹. A significant promoted effect was observed once the atomic ratios of Mn/(Co+Mn) were lower than 10%, for instance, the temperature for 50% conversion decreased to about −60 °C, showing superior catalytic performance compared to the single metal oxide. Especially, the Mn-promoted Co₃O₄ catalyst with a Mn/(Co+Mn) molar ratio of 10% could convert 100% CO after 3000 min of time-on-steam without any deactivation at room temperature. As prepared catalysts were characterized by XRD, N₂-adsorption/desorption, TEM, H₂-TPR, O₂-TPD and CO-titration analysis. The significant enhancement of performance for oxidation of CO over Mn-Co-O mixed oxides was associated with the high active oxygen species concentrations formed during the pretreatment in O₂ atmosphere.     

The thermal conversion of the tetrahydrothiophene‐precursor polymer to poly(p‐phenylene vinylene)

This paper reports the thermal conversion of the tetrahydrothiophene (THT)‐precursor to poly(p‐phenylene vinylene) (PPV). Detailed investigations of the conversion process show that the leaving groups THT and HCl do not eliminate simultaneously. Moderate temperatures (≤125 °C) are sufficient to eliminate the THT while a higher temperature of ≈150 °C is necessary for the leaving group HCl. Furthermore, the THT groups split off at two characteristic temperatures. Our investigations have shown that a consistent picture of the reaction mechanism can only be obtained if the configuration of the polymer chain is considered. For the total reaction of the THT‐precursor to PPV a reaction mechanism is suggested that consists of at least four steps. Copyright © 1999 John Wiley & Sons, Ltd.     

高效锂离子筛吸附剂MnO2·0.5H2O的软化学合成及吸附性能研究

以MnCl2·4H2O,LiOH·H2O等试剂为初始原料,采用溶胶-凝胶、水热处理、固化等软化学合成步骤制备了锂离子筛前驱体Li1.6Mn1.6O4,并经稀盐酸抽锂后得到了高选择性锂离子筛吸附剂MnO2·0.5H2O.着重对合成过程中锂锰比,氧化剂用量等因素影响进行了探讨,并对所制备吸附剂的吸附性能进行了研究.结果表明,经软化学合成步骤制备的锂离子筛对Li 有良好的吸附量和选择性,在未来从海水、卤水等液态锂资源富集或提取锂的应用中具有很大的潜力.