Rational solutions to Q3δ in the Adler-Bobenko-Suris list and degenerations

We derive rational solutions in Casoratian form for the Nijhoff-Quispel-Capel (NQC) equation by using the lattice potential Korteweg-de Vries (lpKdV) equation and two Miura transformations between the lpKdV and the lattice potential modified KdV (lpmKdV) and the NQC equation. This allows us to present rational solutions for the whole Adler-Bobenko-Suris (ABS) list except Q4. The known Miura transformation for soliton solutions between the NQC equation and Q3_δ and the known degenerations for solitons from Q3_δ to Q2, Q1_δ, H3_δ, H2 and H1 in the ABS list are used. We show that the Miura transformation and degenerations are valid as well for rational solutions which are usually considered as “long-wave-limit” of solitons. All the rational solutions can be expressed in terms of {z _j} which are linear functions of (n, m).     

Theoretical line list of D2 O up to 16,000 cm with an accuracy close to experimental

A line list for D₂ ¹⁶O isotopologue of water molecule was calculated in the region 0-16,000 cm⁻¹ with energy levels up to J=30. Variational calculations are based on the semi-theoretical potential energy surface obtained by morphing ab initio potential using the experimental energy levels of D₂ ¹⁶O. For energy levels with J=0, 2, 5 and 10, the standard deviation of the fit is 0.023 cm⁻¹. This line list should make an excellent starting point for spectroscopic modeling and analysis of D₂O rovibrational spectra.     

我国的新型煤化工产业——煤制甲醇

对我国新型煤化工产业煤气化生产合成气和煤制甲醇的生产工艺作了介绍,涉及煤资源综合利用、低碳绿色化学工业、反应条件的选择以及我国新型煤化工产业的发展特点和成就等.     

基于灰色关联度的中国海洋产业结构分析

简要分析了中国海洋经济的发展现状与趋势, 着重对我国主要海洋产业进行了关联度分析, 得出我国海洋经济的支柱产业和主导产业以及海洋产业结构存在的问题, 并据此提出了中国海洋产业结构优化升级对策等方面的建议.     

基于二进制转换的0—1规划隐枚举法

本针对常规隐枚举法，提出了一种基于二进制转换的快速有效枚举出所有可能解的方法，包括旨在加速优化过程的所有可能解的排列规则，并给出了一个算例。     

关于Tuza和Voigt的(Dm,m)-可选择性刻画定理

给出一个不属于Non-D的图,但该图却不是(Dm,m)-可选择的.这表明在Tuza Zs和Voigt M的Non-D定义和(Dm,m)-可选择图的特征化定理中存在一定的冲突.针对如上冲突,对Tuza Zs和Voigh M所给出的Non-D的定义,以及(Dm,m)-可选择图的特征化定理的证明进行了修正.     

全要素生产率和产业结构对能源利用影响的实证分析

本文利用能源消耗模型进行实证分析,结果表明决定能源利用效率的关键因素和长期因素是全要素生产率,全要素生产率的不断提高导致了我国经济快速发展而单位GDP能源消耗不断降低的特殊现象.产业结构对能源消耗有显著的短期影响,当第一产业比例下降或第二产业比例上升时,能源消耗增加。市场化程度、对外开放程度对能源消耗的作用体现在全要素生产率中.2000年后能源消耗重新抬头并不否定全要素生产率的作用,而是缺乏节能意识的负面影响抵消并逆转了全要素生产率的正面作用.     

Defining and optimizing algorithms for neighbouring particle identification in SPH fluid simulations

Lagrangian particle methods such as smoothed particle hydrodynamics (SPH) are very demanding in terms of computing time for large domains. Since the numerical integration of the governing equations is only carried out for each particle on a restricted number of neighbouring ones located inside a cut‐off radius r_c, a substantial part of the computational burden depends on the actual search procedure; it is therefore vital that efficient methods are adopted for such a search. The cut‐off radius is indeed much lower than the typical domain's size; hence, the number of neighbouring particles is only a little fraction of the total number. Straightforward determination of which particles are inside the interaction range requires the computation of all pair‐wise distances, a procedure whose computational time would be unpractical or totally impossible for large problems. Two main strategies have been developed in the past in order to reduce the unnecessary computation of distances: the first based on dynamically storing each particle's neighbourhood list (Verlet list) and the second based on a framework of fixed cells. The paper presents the results of a numerical sensitivity study on the efficiency of the two procedures as a function of such parameters as the Verlet size and the cell dimensions. An insight is given into the relative computational burden; a discussion of the relative merits of the different approaches is also given and some suggestions are provided on the computational and data structure of the neighbourhood search part of SPH codes. Copyright © 2008 John Wiley & Sons, Ltd.     

First passage time for multivariate jump‐diffusion processes in finance and other areas of applications

The first passage time (FPT) problem is an important problem with a wide range of applications in science, engineering, economics, and industry. Mathematically, such a problem can be reduced to estimating the probability of a stochastic process first to reach a boundary level. In most important applications in the financial industry, the FPT problem does not have an analytical solution and the development of efficient numerical methods becomes the only practical avenue for its solution. Most of our examples in this contribution are centered around the evaluation of default correlations in credit risk analysis, where we are concerned with the joint defaults of several correlated firms, the task that is reducible to a FPT problem. This task represents a great challenge for jump‐diffusion processes (JDP). In this contribution, we develop further our previous fast Monte Carlo method in the case of multivariate (and correlated) JDP. This generalization allows us, among other things, to evaluate the default events of several correlated assets based on a set of empirical data. The developed technique is an efficient tool for a number of financial, economic, and business applications, such as credit analysis, barrier option pricing, macroeconomic dynamics, and the evaluation of risk, as well as for a number of other areas of applications in science and engineering, where the FPT problem arises. Copyright © 2008 John Wiley & Sons, Ltd.