Higher Toda Mechanics and Spectral Curves

For each of the Lie algebras gln and g~ln we construct a family of integrable generalizations of the Toda chains characterized by two integers m and m_. The Lax matrices and the equations of motion are given explicitly, and the integrals of motion can be calculated in terms of the trace of powers of the Lax matrix L. For the case of m =m_,we find a symmetric reduction for each generalized Toda chain we found, and the solution to the initial value problems of the reduced systems is outlined. We also studied the spectral curves of the periodic (m ,m_)-Toda chains, which turns out to be very different for different pairs of m and m_. Finally we also obtain the nonabelian generalizations of the (m ,m_)-Toda chains in an explicit form.     

Spectral Energy Density in a Kerr Nonlinear Blackbody

In a Kerr nonlinear blackbody, bare photons with opposite wave vectors and helicities are bound into pairsand unpaired photons are transformed into a new kind of quasiparticle, the nonpolariton. The nonpolariton system constitutes free thermal radiation in the blackbody. The present paper investigates the spectral energy density of the thermal radiation. It is found that the spectral energy density of a Kerr nonlinear blackbody is larger than that of a normal blackbody.     

Anomalous spectral behaviour of diffracted chirped Gaussian pulses in the near field

By using the Fourier transform method, analytical expressions for the axial power spectrum and near-field intensity in the spacetime domain of chirped Gaussian pulses diffracted at an aperture are derived, which permit us to study changes in spectral and temporal profiles of the chirped Gaussian pulses both analytically and numerically. Detailed numerical results and physical analysis show that spectral anomalies take place in the neighbourhood of certain critical distances, and the shifting of maximum and splitting of temporal intensity profiles appear. In particular, for ultrashort chirped pulses, there exists also spectral switch. Besides the truncation parameter, the chirp parameter and pulse duration affect the behaviour of spectral switches.     

Comment on “A Hierarchy of Integrable Nonlinear Lattice Equations and New Integrable Symplectic Map”

Comment on a recent paper on Commun. Theor. Phys. (Beijing, China) 38 (2002) pp. 523-528.     

图的无符号拉普拉斯和距离无符号拉普拉斯特征值

Let G be a simple graph. We first show that ■, where δiand di denote the i-th signless Laplacian eigenvalue and the i-th degree of vertex in G, respectively.Suppose G is a simple and connected graph, then some inequalities on the distance signless Laplacian eigenvalues are obtained by deleting some vertices and some edges from G. In addition, for the distance signless Laplacian spectral radius ρQ(G), we determine the extremal graphs with the minimum ρQ(G) among the trees with given diameter, the unicyclic and bicyclic graphs with given girth, respectively.     

THE WAVE EQUATION APPROACH TO THE TWO-DIMENSIONAL INVERSE PROBLEM FOR A GENERAL BOUNDED DOMAIN WITH PIECEWISE SMOOTH MIXED BOUNDARY CONDITIONS

1 IntroductionLet fl be a simply connected bounded domain in R2 with a smooth boundary 0fl. Considerthe two-dimensional Robin problemwhere k denotes differentiation aIong the inward pointing normal to 0n and 7 is a positiv('constan. Denote its eigenvalues, counted according to multiplicity, byZayed alld Hassall[15'16] l1ave discussed the probleln (1. 1)-(1.2) fOr small / large impedance7 and have determned some geometric quantities of the don1ain n, using tl1e asymptotic ex-pansion of tlie s…     

超高感度CCD摄像传感器的特性分析

介绍了超高感度 CCD(EXview HAD CCD)摄像传感器的概念、结构特点和性能特征。比较了常规的基底为 Nsub、Psub的 CCD传感器和超高动态 CCD传感器各自的灵敏度、饱和信号和暗电流 ,给出了量子转化效率与光波长的关系曲线。结果表明 :超高感度 CCD摄像传感器在减小拖影方面具有突出的优点。     

三维气固两相混合层湍流拟序结构的直接数值模拟

本文对三维气固两相混合层湍流拟序结构进行了直接数值模拟。气相流场应用拟谱方法对Ｎ－Ｓ方程组进行直接求解,通过模拟时间模式的混合层流动,分析流场失稳后涡的卷起、配对、合并及撕裂过程,研究三维混合层湍流拟序结构的演变特征;计算颗粒场时,采用Ｌａｇｒａｎｇｉａｎ方法,针对颗粒不同的Ｓｔｏｋｅｓ数,模拟了颗粒场的瞬态分布,并分析流场三维大涡结构对颗粒分布的影响。     

大口径光学元件检测中的主要误差及其影响

 使用PSD作为大口径光学元件的质量评价标准,标定了测试系统的传递函数,并讨论了在对ICF驱动器中所使用的光学元件进行检测时产生的几种主要误差,分析了这些误差在进行计算和分析时可能造成的影响以及消除的方法。     

“现代谱分析图形软件系统”的一些应用

“现代谱分析图形软件系统”是一个以谱分析为主体的大型软件，它包括了３２种当前典型的现代谱分析方法、经典谱分析方法和其它常用信号分析方法，并具有丰富的图形处理功能。本文介绍了该软件系统的基本功能和主要特点，研究了它在现代谱分析、水声、医疗、语音分析等领域的应用，并分析了有关结果。