BZ反应的滴定量热研究

用滴定热量计考察丙二酸(以下简称MA)-溴酸钾-硝酸铈铵-硫酸振荡体系在不同反应物浓度下周期、诱导期、诱导期放热的变化情况. 发现反应物浓度与周期、诱导期的倒数之间存在着线性关系,并观测到溴酸钾与丙二酸的浓度固定在不同的值时,随着Ce4 浓度的逐渐变稀,振荡周期变短,从动力学理论角度对上述现象进行了分析.     

含连续滞量和阻尼项的非线性双曲偏微分方程组的振动性

研究了一类含连续分布滞量和阻尼项的非线性双曲型偏微分方程组运用黎卡提变换获得了该方程组在两类边值条件下解振动的充分条件.     

Rotating class of parametric resonance processes in coupled oscillators

We single out and elucidate basic features of strongly coupled parametric oscillators as opposed by symmetry to the type reducible to uncoupled Mathieu equations. The strongly coupled type is essential to the oscillations and waves in rotating structures and chiral systems. It exhibits only the main parametric resonance, no higher-order ones. As well, the relaxation–fluctuation behavior is unusual, characterized by a negative-energy oscillation mode that is, nonetheless, stable so the Gibbs statistics lose its force. The models presented are exactly solvable.     

Commutators of fractional integral operators on Vanishing-Morrey spaces

In this note we prove a sufficient condition for commutators of fractional integral operators to belong to Vanishing Morrey spaces VL ^p,λ. In doing this we use an extension on Morrey spaces of an inequality by Fefferman and Stein concerning the sharp maximal function and the fractional maximal function and related Morrey inequalities.      

Study of a Biological Oscillation System by a Microcalorimetric Method

The power–time curves of a biological oscillation system were determined for different temperatures, acidities and carbon sources, by using a 2277 thermal activity monitor. The apparent activation energy and order of the oscillation reaction were calculated from the induction period (t _in) and the first oscillation period (t _p). The regularity of the biological oscillation system is discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

一阶非线性具偏差变元脉冲微分方程

给出了具有时滞和时超的一阶非线性脉冲微分方程所有解为振动的充分条件，所得结论包含了线性情形作为其推论。     

Numerical investigation of the effect of inlet condition on self‐excited oscillation of wet steam flow in a supersonic turbine cascade

Self‐excited oscillation can be induced due to the interaction between condensation process and local transonic condition in condensing flow, which is an important problem in wet steam turbine. With an Eulerian/Eulerian numerical model, the self‐excited oscillation of wet steam flow is investigated in a supersonic turbine cascade. Owing to supercritical heat addition to the subsonic flow in the convergent part of the cascade, the oscillation frequency decreases with increased inlet supercooling. Mass flow rate increases in the oscillating flow due to the greater supersaturation in condensation process, while the increase will be suppressed with the flow oscillation. Higher inlet supercooling leads to the fact that the condensation process moves upstream and the loss increases. Moreover, some predictions of oscillation effects on outflow angle and aerodynamic force are also presented. Finally, heterogeneous condensations with inlet wetness and periodic inlet conditions, as a result of the interference between stator and rotor, are discussed. Copyright © 2008 John Wiley & Sons, Ltd.     

Nonlinear resonances and self-excited oscillations of a rotor caused by radial clearance and collision

This paper investigates oscillations in a flexible rotor system with radial clearance between an outer ring of the bearing and a casing by experiments and numerical simulations. The mathematical model considers the collisions of the bearing with the casing. The following phenomena are found: (1) Nonlinear resonances of subharmonic, super-subharmonic and combination oscillation occur. (2) Self-excited oscillation of a forward whirling mode occurs in a wide range above the major critical speed. (3) Entrainment phenomena from self-excited oscillation to nonlinear forced oscillation occur at these nonlinear resonance ranges. Moreover, this study analyzes periodic solutions of the mathematical model by the Harmonic Balance Method (HBM). As the results, the nonlinear resonances of subharmonic oscillation and its entrainment phenomenon can be explained theoretically by investigating the stability of the periodic solutions. The influence of the static force and the bearing damping on these oscillation are also clarified.     

Matrix characterization of oscillation for double sequences

The notion of oscillation for ordinary sequences was presented by Hurwitz in 1930. Using this notion Agnew and Hurwitz presented regular matrix characterization of the resulting sequence space. The primary goal of this article is to extend this definition to double sequences, which grants us the following definition: the double oscillation of a double sequence of real or complex number is given P-lim sup_{(m,n)→∞;(α,β)→∞}|S _m,n -S _α,β |. Using this concept a matrix characterization of double oscillation sequence space is presented. Other implication and variation shall also be presented.      

二阶时标非线性中立型动力学方程的振动性

运用广义Riccati变换给出时标上二阶非线性中立型动力学方程振动的充分条件,进一步研究了具扰动项的动力学方程解的性态.所得结论推广和改进了已知文献的部分结果.