闭轨道直径函数的不动点

由引入最一般的压缩条件，在完备度量空间中，对一类具有闭轨道直径函数的自映射证明了不动点的存在性．这一条件不仅包活了Ｋａｎｎａｎ型也包括了Ｒｅｉｏｈ型、Ｈａｒｄｙ和Ｒｏｓｅｒｓ型压缩条件．给出的实例表明了本文方法的有效性．

空间系统闭轨道不存在的一个新的判别方法

平面系统的Bendixson准则是极限环理论的一个基本定理,本文将它推广到三维空间系统中。

临时限速场景下基于轨道区段锁闭时间的铁路调度模型研究

当灾害监测系统发出预警、报警信息时,如何精准、快速、有效地执行临时限速并采取应急处置措施从而保证限速情况下列车安全、平稳、高效运行是亟待解决的关键难题。本文研究了临时限速场景下的铁路调度问题,基于轨道区段锁闭时间计算理论和铁路防灾安全监测系统的预警信息,以路网中列车的总延误时间最短为目标构建了运行图优化调整模型。通过精细化计算列车占用各个闭塞分区的时间并在调度模型基础上引入限速约束,该模型保证列车在限速场景下的安全平稳运行,从而辅助行车调度员的行车调整工作,提升应急处置能力。最后以铁岭西至扶余北段为背景设计算例并验证,表明了该调度模型的准确性。

一阶常微分方程可积性研究的初等方法

本文针对一类一阶常微分方程,给出基于变量代换和极坐标变换的求解一阶常微分方程通积分的初等方法,两种方法所得的结果完全一致,从而该方程的可积性可知.进一步地,基于通积分的显式表达式,我们分析获得该方程的全局轨道分布,得到经过退化平衡点的一族周期闭轨的存在性.

裴沟煤矿KJ539轨道运输监控系统应用研究

介绍了裴沟煤矿安装的KJ539轨道运输监控系统基本结构、工作原理、主要功能等。该系统采用了ZigB ee无线传输技术,具有工作可靠、便于维护、操作方便、适应性强等特点。实践表明,该轨道运输监控系统有效解决了主轨道巷机车运输存在的问题,提高了运输效率。

Recurrence spectra of Li atom in strong external fields

Based upon our previous work [Commun. Theor. Phys.. 40,702 (2003)], we developed the closed orbit theory from two degrees of freedom to three non-separable degrees of freedom and calculated the recurrence spectra of Li Rydberg atom in strong perpendicular electric and magnetic fields. The Fourier transformed spectra of Li atom has allowed direct comparison between the resonance peaks and the scaled action values of closed orbits, whereas the nonhydrogenic resonance can be explained in terms of the new orbits created by the core scattering. The semiclassical result is in good agreement with the quantum one, which suggests that our calculation is correct.

关于欧拉动弯曲问题

本文研究了具有Z_2对称性的、在简谐激励、非线性阻尼、联接质量惯性力作用下的杆的欧拉弯曲问题。用与文献[1]不同的方法,讨论了控制方程在参数改变下可能产生的极限环分支、次谐波分枝及Smale马蹄型混沌的存在性。

Absorption and Recurrence Spectra of Sodium Rydberg Atom in a Strong External Magnetic Field

Using core-scattered closed-orbit theory, we calculate the photoabsorption and the scaled recurrence spectra of sodium Rydberg atom in strong magnetic field below ionization threshold. The non-Coulombic nature of the ionic core have been modified by a model potential, which includes an attractive Coulomb potential and a short-ranged core potential. A family of core-scattered nonhydrogenic closed orbits have also been discovered. The Fourier transformed spectra of sodium atom have allowed direct comparison between peaks in such plot and the scaled action values of closed orbits. The new peaks in the recurrence spectra of sodium atom have been considered as effects caused by the core scattering of returning waves at the ionic core. The results are compared with those of hydrogen case, which show that the core-scattered effects play an important role in alkali-metal atoms.

一类切换系统的稳定性

研究了一类切换系统的稳定性。主要介绍了对该切换系统设计了PI控制器,给出了系统全局渐近稳定的充分条件,并给出了周期闭轨道存在的充分必要条件,同时讨论了系统稳定性的其他情况。最后的数值仿真验证了结论的正确性。

列车间不确定性资源请求冲突的预测方法

通过定义列车间不确定性冲突,从冗余时间、机车车辆(车底)和其他因素3个方面分析不确定性冲突的影响因素,提出列车间不确定性冲突的预测方法,最后以某铁路沿线车站为例,在原始数据结构基础上进行异常数据处理,并采用基于轨道区段锁闭时间预测列车间不确定性冲突的方法计算得到不确定性冲突发生概率,以期为提高列车间冲突预测的准确性、疏解冲突、制订更加高效的列车运行调整方案提供可靠依据。

Double—Pulse Spectra and Closed—Orbits：Photodetachment of H^— in parallel Electric and Magnetic Fields

We derive a formula for double-pulse spectra from closed-orbit theory. We then calculate the double-pulse photodetachment spectra of H? in the presence of parallel electric and magnetic fields. We analyze the spectra in terms of closed-orbits of the system. We suggest a method for the measurement of a phase associated with each closed-orbit.

Photodetachment of H^- Near a Dielectric Surface

Using the closed orbit theory, the photodetachment cross section of H- near a dielectric surface has been derived and calculated. The results show that the dielectric surface has great influence on the photodetachment process of negative ion near the ionization threshold. Above the ionization threshold, the photodetachment cross section starts to oscillate. With the increase of the energy, the oscillating amplitude decreases and the oscillating frequency increases. The oscillation in the photodetachment cross section of H- in the presence of a dielectric surface is either larger or smaller than the photodetachment of H- without the surface. As the photon energy is larger than the critical value Epc, the oscillatory structure disappeared and the cross section approaches to the case of the photodetachment of H- without any external fields. For a given detached-electron energy, the photodetachment cross section becomes decreased with the increase of the ion-surface distance. Besides, the dielectric constant has great influence on the photodetachment of H-. With the increase of the dielectric constant, the oscillation in the cross section becomes increased. As the dielectric constant increases to infinity, the cross section is the same as the photodetachment of H- near a metal surface. This study provides a new understanding on the photodetachment process of H- in the presence of a dielectric surface.

Spontaneous Emission of a Polarized Atom in a Medium Between Two Parallel Mirrors

Using the photon closed orbit theory, the spontaneous emission rate of a polarized atom in a medium between two parallel mirrors is derived and calculated. It is found that the spontaneous emission rate of a polarized atom between the mirrors is related to the atomic position and the polarization direction. The results show that in the vicinity of the mirror, the variation of the spontaneous emission rate depends crucially on the atomic polarization direction. With the increase of the polarization angle, the oscillation in the spontaneous emission rate becomes decreased. For the polarization direction parallel to the mirror plane, the oscillation is the greatest; while for the perpendicular polarization direction, the oscillation is nearly vanished. The agreement between our result and the quantum electrodynamics result suggests the correctness of our calculation. This study further verifies that the atomic spontaneous emission process can be effectively controlled by changing the polarization orientation of the atom.

Absorption and Recurrence Spectra of Li Rydberg Atom in Perpendicular Electric and Magnetic Fields

We develop the semi-closed orbit theory from two degrees of freedom to three non-separable degrees of freedom and put forward a new model potential for the Li Rydberg atom, which reduces the study of the system to an effective one-particle problem. Using this model potential and the closed orbit theory for three degrees of freedom, we caiculate the recurrence spectra of Li Rydberg atom in perpendicular electric and magnetic fields. The closed orbits in the corresponding classicai system have also been obtained. The Fourier transformed spectra of Li atom have ailowed direct comparison between the resonance peaks and the scaied action values of closed orbits, whereas the nonhydrogenic resonance can be explained in terms of the new orbits created by the core scattering. Our result is in good agreement with the quantum spectra, which suggests that our calculation is correct.

Absorption and Recurrence Spectra of Nonhydrogenic Rydberg Atom Near a Metal Surface

Multielectron to theoretical treatments atoms near a metal surface are essentially more complicated than hydrogen atom with regard By using the semicalssical dosed orbit theory generalized to the multielecton atoms, we study the dynamical properties of the Rydberg lithium atom near a metal surface. The photoabsorption spectra and recurrence spectra of this system have also been calculated. Considering the effect of the ionic core potential of the Rydberg lithium atom, the number of the closed orbits increases, which leads to more peaks in the recurrence spectra than the case of hydrogen atom near a metal surface. This result shows that the core-scattered effects play an important role in nonhydrogenic atoms. This study is a new application of the closed-orbit theory and is of potential experimental interest.

Correspondence Between Oscillations and Emitted Photon Closed-Orbits in Spontaneous Emission Rate of an Atom Near a Dielectric Slab

We study the oscillations in the spontaneous emission rate of an atom near a dielectric slab. The emission rate is calculated as a function of system size using quantum electrodynamics. It exhibits multi-periodic oscillations. Four frequencies of the oscillations are extracted by Fourier transforms. They agree with actions of photon closed-orbits going away and returning to the atom. These oscillations are explained as manifestations of quantum interference effects between the emitted photon wave near the atom and the returning photon waves travelling along various closed-orbits.

Electron Flux Distributions in the Photodetachment of H_2^-in an Electric Field

The electron flux distributions in the photdetachment of a negative hydrogen molecular ion in an electric field have been studied by using the two-center model and the dosed orbit theory. An analytic formula is presented for the electron flux of H2 in the presence of an electric field. The results show that the interference between the two orbits passing through the given spatial point leads to the oscillation in the electron flux distribution. Besides, the interference between the two centers of the H2^- is also very important. The comparison between the electron flux of H2^- in electric field with the result of H^- shows that at the equilibrium distance of two centers in the H2^-, the interference of the two nuclei on the detached electron＇s flux distribution is very strong, while at larger distance of the two centers, the interference effect of the two centers is decreased.

Oscillations in Total Photodetachment Cross Sections of a Triatomic Anion

The total photodetachment cross section of a linear triatomic anion is derived for arbitrary laser polarization direction. The cross section is ,shown to be strongly oscillatory when the laser polarization direction is parallel to the axis of the system; the oscillation amplitude decreases and vanishes as the angle between the laser polarization and the anion axis increases and becomes perpendicular to the axis. The average cross section over the orientations of the triatomie system is also obtained. The cross section of the triatomic anion is compared with the cross section of a two-center system. We find there are two oscillation frequencies in the triatomie anion in contrast to only one oscillation frequency in the two-center case. Closed-orbit theory is used to explain the oscillations.

Analysis of STC Fault in Urban Rail Transit Station of Mobile Block System

Mobile block system is a new type of block technology based on the theory of interval block. This article focuses on the analysis of safety key points, the efficient use of emergency time, the maximum efficiency of mobilizers, to reduce the loss of emergency incidents and casualties.

Optimization of Telephone Occlusion Method on Urban Rail Transit in Shanghai

Telephone occlusion method is a backup manual occlusion method during an urban rail transit signal equipment failure, which ensures that metro operated safely and orderly. Through the results of several telephone occlusion exercises, find out the shortcomings oftclcphone occlusion method and optimizing it.