受高斯白噪声影响的有限化学反应体系的随机热力学——外噪声对化学反应体系影响的有效热力学量度

通过分析噪声对跃迁概率的不同影响,借助Novikov定理及MSR理论,建立了受多源白噪声影响的有限化学反应体系的有效主方程及有效熵平衡方程,导出非平衡定态时这类噪声体系熵产生的一般表达式,揭示涨落熵产生的统计内涵及噪声贡献,并针对非宏观量级的外噪声,借助扰动按分布参数分离法及有效主方程的Kramers-Moyal展开,进一步对简单加合性噪声建立了非平衡定态宏观稳定性判据的随机模拟,论证了噪声对化学反应体系定态稳定性的弱化作用.     

Bäcklund transformations and abundant exact explicit solutions of the Sharma-Tasso-Olver equation

By using an extension of the homogeneous balance method and Maple, the Bäcklund transformations for the Sharma-Tasso-Olver equation are derived. The connections between the Sharma-Tasso-Olver equation and some linear partial differential equations are found. With the aid of the transformations given here and the computer program Maple 12, abundant exact explicit special solutions to the Sharma-Tasso-Olver equation are constructed. In addition to all known solutions re-deriving in a systematic way, several entirely new and more general exact explicit solitary wave solutions can also be obtained. These solutions include (a) the algebraic solitary wave solution of rational function, (b) single-soliton solutions, (c) double-soliton solutions, (d) N-soliton solutions, (e) singular traveling solutions, (f) the periodic wave solutions of trigonometric function type, and (g) many non-traveling solutions. By using the Airy’s function and the Bäcklund transformations obtained here, the exact explicit solution of the initial value problem for the STO equation is presented. The variety of the structure of the solutions for the Sharma-Tasso-Olver equation is illustrated.     

A Combinatorial Approach to Piecewise Linear Time Series Analysis

Over recent years, several nonlinear time series models have been proposed in the literature. One model that has found a large number of successful applications is the threshold autoregressive model (TAR). The TAR model is a piecewise linear process whose central idea is to change the parameters of a linear autoregressive model according to the value of an observable variable, called the threshold variable. If this variable is a lagged value of the time series, the model is called a self-exciting threshold autoregressive (SETAR) model. In this article, we propose a heuristic to estimate a more general SETAR model, where the thresholds are multivariate. We formulate the task of finding multivariate thresholds as a combinatorial optimization problem. We develop an algorithm based on a greedy randomized adaptive search procedure (GRASP) to solve the problem. GRASP is an iterative randomized sampling technique that has been shown to quickly produce good quality solutions for a wide variety of optimization problems. The proposed model performs well on both simulated and real data.     

Towards the Exact Minimization of BDDs—An Elitism-Based Distributed Evolutionary Algorithm

Binary Decision Diagrams (BDDs) are the state-of-the-art data structure for representation and manipulation of Boolean functions. In general, exact BDD minimization is NP-complete. For BDD-based technology, a small improvement in the number of nodes often simplifies the follow-up problem tremendously. This paper proposes an elitism-based evolutionary algorithm (EBEA) for BDD minimization. It can efficiently find the optimal orderings of variables for all LGSynth91 benchmark circuits with a known minimum size. Moreover, we develop a distributed model of EBEA, DEBEA, which obtains the best-ever variable orders for almost all benchmarks in the LGSynth91. Experimental results show that DEBEA is able to achieve super-linear performance compared to EBEA for some hard benchmarks.     

ON THE MAXIMAL LYAPUNOV EXPONENT FOR A REAL NOISE PARAMETRICALLY EXCITED CO-DIMENSION TWO BIFURCATION SYSTEM (Ⅱ)

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分裂导线自阻尼振动特性研究

为了掌握线路的振动状态,确定线路抗振能力,保证线路安全,需要明确架空输电导线的风致振动响应．本文针对江苏境内某特高压工程LGJ-630/45型导线,建立其振动控制能量平衡方程,编制了Fortran程序以高效准确地求解该超越方程,计算分析了单导线及四种分裂导线微风振动状态下的振动及耗能特性．结果表明,单导线在风振平衡点处的双振幅最大值在最低频率上,约为导线直径的两倍;四种分裂导线风振平衡点处的幅值在15Hz附近达到最大值;导线单位长度功耗在60Hz附近达到最高,功耗能力在较低频域(10Hz~20Hz)上较弱,在较高频域(30Hz~80Hz)较强;导线分裂数越大,分裂导线的振幅越小,八分裂导线的防振消振效果相对最好;四种分裂导线在在10Hz~20Hz频域振动幅值大而单位功耗水平低,因此10Hz~20Hz频段是分裂导线的危险频段,防振措施应该针对这一频段设置．研究方法与成果为LGJ-630/45导线的抗振设计提供了科学依据．     

细颗粒湍流聚并的分区法群平衡模拟

通过聚并促进细颗粒(PM2.5)特别是亚微米颗粒(PM1.0)团聚长大或被大颗粒捕集,是提高其脱除效率的有效方法之一.本文采用分区法对燃煤电厂尾部烟气中飞灰的聚并进行了群平衡模拟研究.利用圆柱阵列实现的湍流聚并装置,圆柱横向间距为4倍直径时,纵向间距宜在圆柱直径的15～30倍之间,在工程上较为可行的条件下,对于PM1....     

The effects of doubly excited states on ionization balance

The effects of highly doubly excited states on ionization balance are investigated. In the calculation, A Collisional-Radiative model in Detailed-Configuration-Accounting (DCA) is applied to population calculations for NLTE plasmas. Configuration-averaged rate coefficients that needed in the rate equations are obtained based on the first order perturbation theory. The Hatree-Fock-Slater self-consistent-field method is used to calculate the electron wave functions. The mean ionization stage of high-Z plasma Lu is presented. The comparison shows that the mean ionization stage increases more than 3 stages when doubly excited states 5l6l' and 5l5l' are not included in the population calculations.     

空间目标的可见光散射与红外辐射

利用Lowtran7大气传输模型计算0.4～0.8μm可见光波段的太阳辐射、大气自身的热辐射以及天地背景辐射.依据粗糙面光散射理论与双向反射分布函数计算空中目标表面对太阳辐射和云层对阳光反射的散射.利用传热学和背景辐射理论,根据能量守恒定律建立空间目标表面温度的热平衡方程.以气球为例,计算不同表面涂层材料的气球,在不同地理位置、不同高度和不同时间条件下,其温度及辐射功率的变化.分析空间目标红外辐射特性的一般规律和特征.     

Backlund Transformation and Exact Solutions for a New Generalized Zakharov-Kuzentsov Equation with Nonlinear Terms of Any Order

In this paper, with the help of symbolic computation, a new Backlund transformation (BT) for a newgeneralized Zakharov-Kuznetsov equation with nonlinear term of any order, ut+aupux +bu2pux +γuxy +δuxxx +ρuxyy=0, is obtained by using the homogeneous balance method. Based on the BT, some exact solutions are presented.