基于OH自由基A2Σ + →X2Πr 电子带系发射光谱的温度测量技术

本文基于OH自由基所固有的分子结构特征,通过分子光谱理论系统地分析和计算了OH自由基A²Σ ⁺ →X²Π_r 电子带系发射光谱的谱线跃迁频率、能级分布以及爱因斯坦自发发射跃迁概率等重要参数.同时结合实际的光谱实验,分析了谱线的自然展宽、碰撞展宽、多普勒展宽以及仪器展宽等各种展宽因素对谱线线型的影响,从理论上计算了任意转动温度、振动温度以及谱线展宽条件下OH自由基A²Σ ^{关键词： 发射光谱 转动温度 振动温度 自发发射爱因斯坦跃迁概率}     

非定常不可压缩Navier-Stokes方程的旋度形式压力校正格式分析

将求解不可压缩流动的旋度形式压力校正格式从Stokes方程延拓到非定常不可压缩Navier-Stokes方程.在第一步需要求解一个线性的对流-扩散方程,在第二步求解一个Stokes问题.首先给出格式的稳定性分析,然后采用P_2—P_1元分别使用标准形式的压力校正格式和旋度形式的压力校正格式进行了数值模拟,模拟结果表明,对于速度的L~2,H~1误差,两种格式几乎一样,对于压力的L~2误差,旋度形式的压力校正格式略有改进.     

Optimal rigid body motions,part 2: Minimum time solutions

The time-optimal control of rigid-body angular rates is investigated in the absence of direct control over one of the angular velocity components. The existence of singular subarcs in the time-optimal trajectories is explored. A numerical survey of the optimality conditions reveals that, over a large range of boundary conditions, there are in general several distinct extremal solutions. A classification of extremal solutions is presented, and domains of existence of the extremal subfamilies are established in a reduced parameter space. A locus of Darboux points is obtained, and global optimality of the extremal solutions is observed in relation to the Darboux points. The continuous dependence of the optimal trajectories with respect to variations in control constraints is noted, and a procedure to obtain the time-optimal bang-bang solutions is presented.This work was supported in part by DARPA under Contract No. ACMP-F49620-87-C-0016, by SDIO/IST under Contract No. F49620-87-C0088, and by Air Force Grant AFOSR-89-0001.     

What price the spin-statistics theorem?

We examine a number of recent proofs of the spin-statistics theorem. All, of course, get the target result of Bose-Einstein statistics for identical integral spin particles and Fermi-Dirac statistics for identical half-integral spin particles. It is pointed out that these proofs, distinguished by their purported simple and intuitive kinematic character, require assumptions that are outside the realm of standard quantum mechanics. We construct a counterexample to these non-dynamical kinematic ‘proofs’ to emphasize the necessity of a dynamical proof as distinct from a kinematic proof. Sudarshan’s simple non-relativistic dynamical proof is briefly described. Finally, we make clear the price paid for any kinematic ‘proof’.     

Harris公式和ab公式对超形变核转动带的适用性的比较

对A≈190区超变形转动带分别用Harris二参数公式和ab公式进行了系统分析.分析结果表明,与正常变形核动带的情况相似,Harris公式与实验有明显的系统偏离,而ab公式则与实验很接近,可以相当精确和方便地描述超变形转动带.     

Error analysis of the L2 least‐squares finite element method for incompressible inviscid rotational flows

In this article we analyze the L² least‐squares finite element approximations to the incompressible inviscid rotational flow problem, which is recast into the velocity‐vorticity‐pressure formulation. The least‐squares functional is defined in terms of the sum of the squared L² norms of the residual equations over a suitable product function space. We first derive a coercivity type a priori estimate for the first‐order system problem that will play the crucial role in the error analysis. We then show that the method exhibits an optimal rate of convergence in the H¹ norm for velocity and pressure and a suboptimal rate of convergence in the L² norm for vorticity. A numerical example in two dimensions is presented, which confirms the theoretical error estimates. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2004     

相对论性定轴转动变质量系统的广义Noether定理

研究相对论性定轴转动变质量系统的广义Noether定理,首先给出相对论性定轴转动变质量非完整系统的运动方程的Routh形式;其次利用Hamilton作用量在无限小变换下的不变性,研究了相对论性定轴转动变质量非完整系统的广义Noether定理和相对论性定轴转动变质量非完整系统的广义Noether逆定理;结论具有普遍意义,对于经典情形和相对论情形都适用,若m_(oi)为常量,结果化为相对论性定轴转动常质量的Noether定理;若θ《Г_i,ω_i《Г_i结果化为经典定轴转动变质量系统的初Noether定理;若m_(oi)为常量,且θ_i《Г_i,ω_i《Г_i,则结果化为经典定轴转动常质量系统的Noether定理。     

High-resolution infrared and theoretical study of four fundamental bands of gaseous 1,3,4-oxadiazole between 800 and 1600 cm

The Fourier transform infrared spectrum of gaseous 1,3,4-oxadiazole, C₂H₂N₂O, has been recorded in the 800–1600 cm⁻¹ wavenumber region with a resolution around 0.0030 cm⁻¹. The four fundamental bands ν₉(B₁; 852.5 cm⁻¹), ν₁₄(B₂; 1078.5 cm⁻¹), ν₄(A₁; 1092.6 cm⁻¹), and ν₂(A₁; 1534.9 cm⁻¹) are analyzed by the standard Watson model. Ground state rotational and quartic centrifugal distortion constants are obtained from a simultaneous fit of ground state combination differences from three of these bands and previous microwave transitions. Upper state spectroscopic constants are obtained for all four bands from single band fits using the Watson model. The ν₄ and ν₁₄ bands form a c-Coriolis interacting dyad, and the two bands are analyzed simultaneously by a model including first and second order Coriolis resonance using the ab initio predicted Coriolis coupling constant . An extended local resonance in ν₂ is explained as higher order b-Coriolis type resonance with ν₆ + ν₁₀, which is further perturbed globally by the ν₁₅ + ν₁₀ level. A fit of selected low-J transitions to a triad model including ν₂(A₁), ν₆ + ν₁₀(B₁), and ν₁₅ + ν₁₀(A₂) using an ab initio calculated Coriolis coupling constant is performed.The rotational constants, ground state quartic centrifugal distortion constants, anharmonic frequencies, and vibration–rotational constants (α-constants) predicted by quantum chemical calculations using a cc-pVTZ and TZ2P basis with B3LYP methodology, are compared with the present experimental data, where there is generally good agreement. A complete set of anharmonic frequencies and α-constants for all fundamental levels of the molecule is given.