HO3、HO+3、HO-3光谱和结构的MP2和DFT理论研究

用B3LYP和MP2量子化学理论 ,详细地计算了HO3 、HO+ 3 、HO-3 可能的平衡构型、能量和光谱参数 ,分析了它们可能的解离通道和稳定性 .还分析了HO3 的电离势 (IE)及电子亲和势 (Ea) ,讨论了HO3 、HO3 -自由基的光电子能谱的特征 ,及用光电子能谱去探测HO3 的可能性     

The rotational spectrum and hyperfine structure of arsenic monophosphide, AsP

Arsenic monophosphide has been prepared by laser ablation of arsenic in the presence of PH₃. The J = 2-1 and 1-0 transitions in both the ground and first excited vibrational states have been measured with a cavity pulsed jet Fourier-transform microwave spectrometer. An improved equilibrium internuclear distance (r_e) has been obtained. Hyperfine structure in the rotational spectrum of AsP has been resolved and has led to the first determinations of the As nuclear quadrupole coupling constant and both nuclear spin-rotation constants. The data enable the electronic structure of AsP to be compared with those of other mixed Group 15 diatomic molecules.     

J-TEXT 装置等离子体平衡重建与集成运算

利用Matlab 语言将EFIT 程序反演计算过程进行优化整合,简化了程序操作步骤,并增加了对计算结果的分析与存储功能。利用整合后的EFIT 程序,计算分析了J-TXET 装置放电过程中等离子体磁场位形和其它参数的演变,绘制了等离子体压强剖面图、等离子体电流密度和安全因子分布等磁面信息的重建结果。此外,还将反演结果与软X 射线测算数据进行比对。结果表明,改善后的EFIT 程序能够初步满足对实验放电的反演计算分析要求,为J-TXET 装置的放电控制和运行提供重要的参考数据。     

Bulk singularities at critical end points: a field-theory analysis

A class of continuum models with a critical end point is considered whose Hamiltonian [φ,ψ] involves two densities: a primary order-parameter field, φ, and a secondary (noncritical) one, ψ. Field-theoretic methods (renormalization group results in conjunction with functional methods) are used to give a systematic derivation of singularities occurring at critical end points. Specifically, the thermal singularity ∼ | t|^{2 - α} of the first-order line on which the disordered or ordered phase coexists with the noncritical spectator phase, and the coexistence singularity ∼ | t|^{1 - α} or ∼ | t|^β of the secondary density <ψ> are derived. It is clarified how the renormalization group (RG) scenario found in position-space RG calculations, in which the critical end point and the critical line are mapped onto two separate fixed points _CEP ^* and _λ ^*, translates into field theory. The critical RG eigenexponents of _CEP ^* and _λ ^* are shown to match. _CEP ^* is demonstrated to have a discontinuity eigenperturbation (with eigenvalue y = d), tangent to the unstable trajectory that emanates from _CEP ^* and leads to _λ ^*. The nature and origin of this eigenperturbation as well as the role redundant operators play are elucidated. The results validate that the critical behavior at the end point is the same as on the critical line. Received 18 January 2001     

HL-2A��������ʵʱƽ���ؽ���GPU���л�

描述了HL-2A等离子体实时平衡重建的GPU并行化算法,主要包括G-S方程的并行化处理、三对角方程求解、网格边界磁通计算以及一系列矩阵相乘的并行加速.并行后,在129×129的网格下完成一次迭代计算需要约575μs.     

Bandwidth allocation strategy for traffic systems of scale-free network

In this Letter, the bandwidth resource allocation strategy is considered for traffic systems of complex networks. With a finite resource of bandwidth, an allocation strategy with preference parameter α is proposed considering the links importance. The performance of bandwidth allocation strategy is studied for the local routing protocol and the shortest path protocol. When important links are slightly favored in the bandwidth allocation, the system can achieve the optimal traffic performance for the two routing protocols. For the shortest path protocol, we also give a method to estimate the network traffic capacity theoretically.     

The theoretical analysis of the lattice hydrodynamic models for traffic flow theory

The lattice hydrodynamic model is not only a simplified version of the macroscopic hydrodynamic model, but also connected with the microscopic car following model closely. The modified Korteweg-de Vries (mKdV) equation related to the density wave in a congested traffic region has been derived near the critical point since Nagatani first proposed it. But the Korteweg-de Vries (KdV) equation near the neutral stability line has not been studied, which has been investigated in detail for the car following model. We devote ourselves to obtaining the KdV equation from the original lattice hydrodynamic models and the KdV soliton solution to describe the traffic jam. Especially, we obtain the general soliton solution of the KdV equation and the mKdV equation. We review several lattice hydrodynamic models, which were proposed recently. We compare the modified models and carry out some analysis. Numerical simulations are conducted to demonstrate the nonlinear analysis results.     

A higher-order macroscopic model for pedestrian flows

This paper develops a higher-order macroscopic model of pedestrian crowd dynamics derived from fluid dynamics that consists of two-dimensional Euler equations with relaxation. The desired directional motion of pedestrians is determined by an Eikonal-type equation, which describes a problem that minimizes the instantaneous total walking cost from origin to destination. A linear stability analysis of the model demonstrates its ability to describe traffic instability in crowd flows. The algorithm to solve the macroscopic model is composed of a splitting technique introduced to treat the relaxation terms, a second-order positivity-preserving central-upwind scheme for hyperbolic conservation laws, and a fast-sweeping method for the Eikonal-type equation on unstructured meshes. To test the applicability of the model, we study a challenging pedestrian crowd flow problem of the presence of an obstruction in a two-dimensional continuous walking facility. The numerical results indicate the rationality of the model and the effectiveness of the computational algorithm in predicting the flux or density distribution and the macroscopic behavior of the pedestrian crowd flow. The simulation results are compared with those obtained by the two-dimensional Lighthill-Whitham-Richards pedestrian flow model with various model parameters, which further shows that the macroscopic model is able to correctly describe complex phenomena such as “stop-and-go waves” observed in empirical pedestrian flows.     

系统-热库模型平衡约化密度矩阵的精确计算:多层多构型含时Hartree方法及其与多电子态路径积分分子动力学方法的比较

An efficient and accurate method for computing the equilibrium reduced density matrix is presented for treating open quantum systems characterized by the system-bath model. The method employs the multilayer multiconfiguration time-dependent Hartree theory for imaginary time propagation and an importance sampling procedure for calculating the quantum mechanical trace. The method is applied to the spin-boson Hamiltonian, which leads to accurate results in agreement with those produced by the multi-electronic-state path integral molecular dynamics method.     

Multiclass first-order simulation model to explain non-linear traffic phenomena

With the first-order traffic model of Lighthill, Whitham and Richard (LWR), many simple traffic problems can be represented analytically such as a shock formation. However, the LWR model has some deficiencies. For example, among the other things, it fails to replicate interesting non-linear phenomena such as hysteresis and capacity drop as well as the dispersion of traffic platoon when there exists a distribution of desired speeds in heterogeneous traffic. To this end, in this paper, we propose a novel multiclass first-order simulation model based on an approximation of Riemann solver. In the developed model, each vehicle class is only characterized by their desired speeds in a free-flow traffic state where overtaking is allowed. However, when traffic is congested, all vehicle classes must travel at the same congested speed and overtaking is not possible. Numerical results show that the proposed model is not only more accurate and reliable than the existing models but also able to explain non-linear traffic phenomena on freeways.