带粘弹性边界条件的耦合非线性波动方程组的整体可解性

本文讨论了两根非线性弹性杆的耦合问题，利用沿特征线积分与能量估计相结合的方法证明了在该系统一端及两杆之间用某一粘弹性单元连接时，具小初值的初边值问题存在整体经典解     

弦线中的波动方程T0（a^2y）／（ax^2）=η（a^2y）／（at^2）对大扰动也成立

一般教材中，在讨论一维弦线中的横波波动方程时，都假设弦线中的张力为恒量，在小扰动情况下，推导横波波动方程，本文在较一般情况下，推导一维弦线中的横波波动方程，并讨论弦线中张力的变化等问题，所得结果在小扰动近似下，与一般教材中的结论一致。     

Ring-opening Polymerization of ε-Caprolactone Using Lanthanide Tris（4-tert-butylphenolate）s as a Single-component Initiator

The ring-opening polymerization of ε-caprolactone (CL) initiated by novel singlelanthanide tris(4-tert-butylphenolate)s [Ln(OTBP)3] is reported. Single-component La(OTBP)3can effectively prepare polycaprolactone (PCL) with over 90% yield and viscosity averagemolecular weight about 60 × 103 under quite mild conditions: molar ratio of CL to initiator is 1000,60 ℃, 2 h in toluene. Mechanism study indicates that the monomer inserts into the growing chainvia the break of acyl-oxygen bond of CL.     

水波实验中相位的微机控制

一、引言水波实验能形象地表演“球面波”、“平面波”的传播规律,直观地反映波的反射、衍射、干涉等现象的基本特征,是物理教学中常规的演示实验之一。水波实验通常用玩具电动机或电磁铁驱动的振子作波源,也可用液滴激发水波。这些方法虽然简单、可靠,效果也不错,但是都难以任意调整振动的相位,从而使演示内容受到限制。我们把单片微机与电磁振子结合在一起,实现了多波源频率和相位的程序控制,增加了水波实验的内容。二、原理水波实验要求振子有稳定的频率和相位,至于振子是否作简谐振动,则没有严格要求。因此完全可以用方波来驱动如图1所示的电磁振子(可用小型继电器改装),随着衔铁的吸合与松开,带动小     

Optimal Design of Dual-Pump Fibre-Optical Parametric Amplifiers with Dispersion Fluctuations Based on Hybrid Genetic Algorithm

Solutions of dual-pump fibre-optical parametric amplifiers (DP-FOPAs) with dispersion fluctuations are derived by using a matrix operator. Based on these solutions and a hybrid genetic algorithm, we have optimized threesection DP-FOPAs to increase the signal band and improve the gain uniformity. The optimizations demonstrate that when dispersion fluctuations are taken into account, the 44-nm signal band with the 0.37-dB ripple and over 14.8-dB gain can be obtained from the three-section DP-FOPA, instead of the lowest gain of -13dB with the ripple of more than 15dB from the single-section DP-FOPA.     

基于Fourier分析的中国股市波动周期研究

通过对沪深两市波动周期的实证分析 ,揭示了中国股市的周期性波动特征 ,并对两市波动的周期性进行了对比 ,为进一步研究我国资本市场的波动提供了依据 .     

中国股票市场波动非对称性特征研究

利用三种 GARCH-M模型实证分析了中国股票市场不同发展阶段波动的非对称性特征 .结果发现 ,中国股票市场存在显著的波动非对称性 ,并且在不同阶段呈现不同特点 .对三种模型进行比较的结果显示 ,EGARCH-M模型是描述中国股市波动非对称性特征的最优模型 .     

SHARP CRITERIONS OF GLOBAL EXISTENCE AND COLLAPSE FOR COUPLED NONLINEAR SCHRODINGER EQUATIONS

In this paper, a series of sharp criterions of global existence and collapse for coupled nonlinear Schr6dinger equations are derived out in terms of the characteristics of the ground state and the local theories. And the conclusion that how small the initial data are, the global solutions exist is proved.     

CAUCHY PROBLEM FOR QUASILINEAR HYPERBOLIC SYSTEMS WITH CHARACTERISTICS WITH CONSTANT MULTIPLICITY

For quasilinear hyperbolic systems with characteristics of constant multiplicity, suppose that characteristics of constant multiplicity(> 1) are linearly degenerate, by means of generalized normalized coordinates we get the global existence and the blow-up phenomenon of the C^1 solution to the Cauchy problem under an additional hypothesis.