具有阻尼项的二阶非线性微分方程的区间振动准则

本文研究一类具有阻尼项的二阶非线性微分方程,利用平均函数和一个广义Riccati变换,得到了该方程的新的区间振动准则,这些准则不同于已知的依赖于整个区间[t0,∞)的性质的结果,而是仅依赖于区间[t0,∞)的子区间列的性质．所得结果推广和改进了Kong的振动准则．特别,还给出了几个例子以说明本文所得结果的优越性．     

A2B模型的阻尼振动

借助数学软件MATLAB,求出了A2B模型阻尼振动的解析解,并讨论其算例的振动图像.     

一类吸引玻色-爱因斯坦凝聚的坍塌性质

本文讨论出现在吸引玻色—爱因斯坦凝聚中的一类带调和势的阻尼非线性Schroedinger方程，对照玻色—爱因斯坦凝聚的物理性质，我们证明了其初值问题在有限时间内的坍塌性质。     

Application of Jacobian Elliptic Functions to the Analysis of the Steady-State Solution of the Damped Duffing Equation with Driving Force of Elliptic Type

In this work, Jacobian elliptic functions are applied to obtain the approximate steady-state solution of the damped Duffing equation with driving force of elliptic type. We assume that the damping coefficient and the nonlinear term need not be small. Numerical comparison between the approximate solution and the numerical integration indicates that our proposed approximate steady-state solution captures well the amplitude-time vibrational response. We have also found that for a certain range of values of the driving frequency ω_f and for a stiff spring, there are one, three, or five possible motions for the elliptic excitation amplitude-frequency response curve.     

QUANTUM FLUCTUATIONS IN A MESOSCOPIC DAMPED LC PARALLEL CIRCUIT IN DISPLACED SQUEEZED FOCK STATE

We study the quantum effects of a damped LC parallel circuit considering its different performance from an RLC series circuit in classical physics. The damped LC parallel circuit with a source is quantized and the quantum fluctuations of magnetic flux and electric charge in the circuit in displaced squeezed Fock state are investigated. It is shown that, as in the RLC series circuit, the fluctuations only depend on the squeezing parameter and the parameters of the circuit components in the damped LC parallel circuit, but the effects of the circuit components on the fluctuations are different in the two circuits.     

I. The properties of hot Ca-like fragments from the 40Ca + 40Ca reaction at 35AMeV

The creation of hot Ca-like fragments was investigated in the ⁴⁰Ca + ⁴⁰Ca reaction at 35 AMeV. Using the AMPHORA 4π detector system, the primary projectile-like fragment was reconstructed and its properties were determined. Both primary and secondary distributions are compared with the predictions of a Monte Carlo code describing a heavy-ion collision as a two-step process. Some of the nucleons which are identified as participants in the first step are transferred in the second step to these final states, which correspond on the average to the maximum value of entropy (thermodynamic probability). The model allows for competition between mean-field effects and nucleon-nucleon interactions in the overlap zone of the interacting nuclei. The analysis presented here suggests a thermalized source picture of the decay of the projectile-like fragment. The validity of the reconstruction procedure for projectile-like fragments is discussed. Received: 12 March 2001 / Accepted: 20 June 2001     

阻尼振动的回复时间最短时所满足的条件

本文指出在讨论阻尼振动的回复时间时必须要考虑仪器的测量精度才有意义,而且并非临界阻尼运动的回复时间最短,而是本文所定义的“弱阻尼振动的临界状态”的回复时间最短,进而导出了在给定测量精度时最短回复时间所满足的方程。     

重掺硅衬底片的内吸除效应

本文研究了重掺p型(B)和重掺n型(P、As、Sb)硅单晶的内吸除效应.发现在本实验条件下,经过改进的内吸杂(IG)处理后,不同掺杂剂的重掺硅单晶片都出现了氧沉淀增强现象,但不同掺杂剂的重掺硅单晶中氧沉淀形态不同.且发现砷增强了硅片近表层区氧的外扩散.在相同的热处理条件下,不同掺杂剂的重掺硅清洁区宽度不同,重掺硼硅片的清洁区最窄,重掺砷的最宽.