The closed-orbit and the photoabsorption spectra of the Rydberg hydrogen atom between two parallel metallic surfaces

Using the closed orbit theory, we study the classical motion and calculatethe photoabsorption spectra of Rydberg hydrogen atom between two parallel metallic surfaces. The results show that the metallic surfaces have a significant effect on the photoabsorption process. When the distances between the hydrogen atom and the two metallic surfaces are close to a critical value dc, the number of the closed orbits is the greatest. When the distance larger or smaller than dc, the number of the closed orbits decreases and the absorption spectra are shown to exhibit a damping oscillation. This work is an interesting new application of closed-orbit theory and is of potential experimental interest.

Closed form solution of stress intensity factors for cracks emanating from surface semi-spherical cavity in finite body with energy release rate method

In this paper, a new semi-analytical and semi-engineering method of the closed form solution of stress intensity factors （SIFs） of cracks emanating from a surface semi-spherical cavity in a finite body is derived using the energy release rate theory. A mode of crack opening displacements of a normal slice is established, and the normal slice relevant functions are introduced. The proposed method is both effective and accurate for the problem of three-dimensional cracks emanating from a surface cavity. A series of useful results of SIFs are obtained.

Study of Electron Orbits for Formation of Toroidal Closed Flux Surface by ECH

Electron orbits under the external vertical field （Bv） and the self poloidal field of the toroidal plasma current in a toroidal geometry are investigated by using analytic model fields in order to search for the conditions of occurence of appropriate confinement asymmetry of fast electrons along the field lines. This asymmetry efficiently and quickly generates a toroidal current, which may close the field lines in ECH-started plasmas. It is analytically shown that the characteristics of confinement asymmetry depend on the product of the major radius and the strength of the external vertical field. The results suggest that in large devices By should be lowered and also some artificial means to speed up the pitch angle scattering for the fast electrons at a higher energy range are beneficial to generate the toroidal current in order to close the filed

Closed-form solutions for free vibration of rectangular FGM thin plates resting on elastic foundation

This article presents closed-form solutions for the frequency analysis of rectangular functionally graded material (FGM) thin plates subjected to initially in-plane loads and with an elastic foundation. Based on classical thin plate theory, the governing differential equations are derived using Hamilton's principle. A neutral surface is used to eliminate stretching-bending coupling in FGM plates on the basis of the assumption of constant Poisson's ratio. The resulting governing equation of FGM thin plates has the same form as homogeneous thin plates. The separation-of-variables method is adopted to obtain solutions for the free vibration problems of rectangular FGM thin plates with separable boundary conditions, including, for example, clamped plates. The obtained normal modes and frequencies are in elegant closed forms, and present formulations and solutions are validated by comparing present results with those in the literature and finite element method results obtained by the authors. A parameter study reveals the effects of the power law index n and aspect ratio a/b on frequencies.

Photodetachment of negative ion in a gradient electric field near a metal surface

Based on closed-orbit theory, the photodetachment of H- in a gradient electric field near a metal surface is studied. It is demonstrated that the gradient electric field has a significant influence on the photodetachment of negative ions near a metal surface. With the increase of the gradient of the electric field, the oscillation in the photodetachment cross section becomes strengthened. Besides, in contrast to the photodetachment of H- near a metal surface in a uniform electric field, the oscillating amplitude and the oscillating region in the cross section of a gradient electric field also become enlarged. Therefore, we can use the gradient electric field to control the photodetachment of negative ions near a metal surface. We hope that our results will be useful for understanding the photodetachment of negative ions in the vicinity of surfaces, cavities, and ion traps.

The influence of electric field on the photodetachment of H^- near a metal surface

The influence of electric field on the photodetachment of H- near a metal surface is investigated based on the closed-orbit theory. It is found that the photodetachment of H- near a metal surface is not only related to the electric field strength but also to the electric field direction. If the electric field is along the ＋z axis, it can strengthen the oscillation in the photodetachment cross section. However, if the electric field is along the -z axis, since the direction of electric field force is opposite to that of static-image force caused by the metal surface, the situation becomes much more complicated. When the electric field is very weak, its influence can be neglected. The photodetachment cross section is nearly the same as that when a single metal surface exists. When the electric field strength is strong enough, the electric field force is able to counteract the metallic attraction, therefore no closed orbit is formed. If the electric field continues to increase until its influence becomes dominant, the photodetachment cross section approaches the case of the photodetachment of H^- in an electric field. Our results may be useful for guiding future experimental studies on the photodetachment of negative ions near surfaces.

Magnetic field effect in photodetachment from negative ion in electric field near metal surface

Based on the closed-orbit theory, the magnetic field effect in the photodetachment of negative ion in the electric field near a metal surface is studied for the first time. The results show that the magnetic field can produce a significant effect on the photodetachment of negative ion near a metal surface. Besides the closed orbits previously found by Duet al. for the H in the electric field near a metal surface （J. Phys. B 43 035002 （2010））, some additional closed orbits are produced due to the effect of magnetic field. For a given ion surface distance and an electric field strength, the cross section depends sensitively on the magnetic field strength. As the magnetic field strength is very small, its influence can be neglected. With the increase of the magnetic field strength, the number of the closed orbits increases greatly and the oscillation in the cross section becomes much more complex. Therefore we can control the photodetachment cross section of the negative ion by changing the magnetic field strength. We hope that our results may guide future experimental studies for the photodetachment process of negative ion in the presence of external fields and surfaces.

Photodetachment of H^- Near a Dielectric Surface

用关上的轨道理论， H 的 photodetachment 十字节？近，绝缘的表面被导出并且计算。结果证明绝缘的表面在电离阀值附近在否定离子的 photodetachment 过程上有大影响。在电离阀值上面， photodetachment 十字节开始震荡。随精力的增加，震荡的振幅减少，震荡的频率增加。在 H 的 photodetachment 十字节的摆动？面对绝缘的表面比 H 的 photodetachment 更大或小吗？没有表面。因为光子精力比批评价值 Epc 大，摆动的结构消失了并且 H 的 photodetachment 的盒子的生气的节途径吗？在任何外部地外面。为一个给定的分开电子的精力， photodetachment 十字节变得随离子表面距离的增加减少了。而且，绝缘的常数在 H 的 photodetachment 上有大影响 ? 。随绝缘的常数的增加，在生气的节的摆动变得增加。作为到无穷的绝缘的经常的增加，生气的节与 H 的 photodetachment 一样吗？接近金属表面。这研究在 H 的 photodetachment 过程上提供新理解吗？面对电介质出现。

Control of the photodetachment of H^-near a metallic sphere surface by an elastic interface

According to the closed-orbit theory, we study the influence of elastic interface on the photodetachment of H- near a metallic sphere surface. First, we give a clear physical description of the detached electron movement between the elastic interface and the metallic sphere surface. Then we put forward an analytical formula for calculating the photodetachment cross section of this system. Our study suggests that the photodetachment cross section of H is changed with the distance between the elastic interface and H^-. Compared with the photodetachment cross section of H^- near a metallic sphere surface without the elastic interface, the cross section of our system oscillates and its oscillation is strengthened with the decrease of the distance from the elastic interface to H^-. In additon, our calcuation results suggest that the influence of the elastic interface becomes much more significant when it is located in the lower half space rather than in the upper half space. Therefore, we can control the photodetachment of H^- near a metallic sphere surface by changing the position of the elastic interface. We hope that our work is conducive to the understanding of the photodetachment process of negative ions near interfaces, cavities and ion traps.

A TECHNIQUE OF DIGITAL SURFACE MODEL GENERATION

It is usually a time-consuming process to real-time set up 3D digital surface model(DSM) of an object with complex surface.On the basis of the architectural survey project of"Chilin Nunnery Reconstruction",this paper investigates an easy and feasible way,that is,on project site,applying digital close range photogrammetry and CAD technique to establish the DSM for simulating ancient architectures with complex surface.The method has been proved very effective in practice.

The effect of the attractive well of the potential energy surface for Ne-HC1 on rotationally inelastic partial wave cross sections

An interaction potential of the Ne-HC1 van der Waals complex is obtained by utilizing the Huxley analytic potential function to fit the accurate interaction energy data, which have been computed at the coupled cluster singles and doubles including connected triple excitations level and with the augmented correlation consistent polarized valence quintuple zeta basis set extended with a set of 3s3p2dlflg mid-bond functions [CCSD （T）/aug-cc-pV5Z-33211]. The close coupling calculation of state-to-state partial cross sections for collision of Ne with HC1 is first performed by employing the fitted interaction potential. This calculation is performed at the incident energies： 40, 60, 75 and 100 meV, separately. The effects of the long-range attractive and the short-range anisotropic interactions on the inelastic state-to-state partial cross sections are discussed in detail. Two maxima are present in the rotationally inelastic partial cross sections and they originate from different mechanisms.

Semiclassical Calculation of Recurrence Spectra of Rydberg Hydrogen Atom Near a Metal Surface

用关上的轨道理论，我们在金属表面附近给对 Rydberg 氢原子的清楚的物理图画描述并且推测 Fourier 在电离阀值下面在不同放大精力转变了这个系统的复发系列。结果证明随放大精力的增加，关上的轨道的数字极大地增加。一些轨道被垂直轨道的分叉创造。这个盒子相当类似于在一个电场的 Rydberg 原子。当放大能量而且增加时，混乱轨道出现。这研究在金属表面附近在 Rydberg 原子的动态行为上提供一个不同观点。

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

金属表面附近的 Multielectron 原子是实质上比关于理论处理的氢原子更复杂。由使用关上的轨道理论概括了到 multielecton 原子的 semicalssical，我们在金属表面附近学习 Rydberg 锂原子的动态性质。这个系统的相片吸收系列和复发系列也是计算的。就 Rydberg 锂原子的离子的核心潜力的效果而言，关上的轨道增加的数字，它导致更多在金属表面附近比氢原子的盒子在复发系列达到顶点。这结果证明散布核心的效果在 nonhydrogenic 原子起一个重要作用。这研究是靠近轨道的理论的新应用并且具有潜在的试验性的兴趣。

Correspondence between classical dynamics and recurrence spectra of Rydberg hydrogen atom near a metal surface

The chaotic behaviours of the Rydberg hydrogen atom near a metal surface are presented. A numerical comparison of Poincare surfaces of section with recurrence spectra for a few selected scaled energies indicates the correspondence between classical motion and quantum properties of an excited electron. Both results demonstrate that the scaled energy dominates sensitively the dynamical properties of system. There exists a critical scaled energy εc, for ε 〈 εc, the system is near-integrable, and as the decrease of ε the spectrum is gradually rendered regular and finally turns into a pure Coulomb field situation. On the contrary, if ε 〉 εc, with the increase of ε, the system tends to be non-integrable, the ergodic motion in phase space presages that chaotic motion appears, and more and more electrons are adsorbed on the metal surface, thus the spectrum becomes gradually simple.

碳酸盐岩储层闭合酸化模拟研究

酸压裂缝生产一段时间后导流能力会逐渐降低,常采用闭合酸化来提高已酸压裂缝的导流能力,闭合酸化模拟对闭合酸化设计意义重大,因此,针对该问题进行闭合酸化建模及数值模拟。首先,基于达西定理、物质平衡原理、酸岩反应动力学建立闭合酸化数学模型;然后通过地质统计学中的序贯高斯模拟算法生成具有非均质性和空间关联性的初始裂缝宽度空间分布和裂缝表面基质渗透率分布;利用有限体积法对模型进行数值求解,用C++编制模拟计算程序;最后基于该模型进行广泛的数值模拟研究,分析酸液分布规律、裂缝表面溶蚀规律、酸液作用距离的影响因素及规律,并形成各种条件下的酸液作用距离图版。研究表明,初始裂缝宽度和裂缝表面粗糙度对裂缝表面溶蚀形态起主导作用,裂缝面溶蚀形态有均匀推进、指进溶蚀和沟槽溶蚀;裂缝宽度越小、粗糙度越大,裂缝表面溶蚀竞争越强烈,越容易形成沟槽,酸液作用距离越远;排量、注酸量正相关于活酸作用距离,酸液传质系数负相关于活酸作用距离;典型的施工排量、酸液用量、常用的酸液类型下,闭合酸化中酸液作用距离为20~60 m。此模型可以预测不同条件下酸液作用距离和酸蚀裂缝表面溶蚀形态,优化闭合酸化参数,为现场闭合酸化施工设计提供理论依据和指导。

闭式叶环开槽电解加工流场仿真与阴极结构优化

闭式叶环是一类减重性能优越的整体构件,但因其结构闭式,开敞性差,通道狭窄扭曲,刀具进给空间有限,加工十分困难。电解加工为非接触式特种加工方法,具有加工不受材料力学性能影响、工具阴极无损耗、加工效率高等优势,是加工闭式叶环的重要方法之一。闭式叶环开槽电解加工的流场研究较少,流场稳定性有待提升。针对闭式叶环开槽电解加工,采用了正流式供液的流动方式,开展了1 mm、2 mm、3 mm出液缝宽下的流场仿真和优化研究,结果表明:(1)采用出液缝宽度为2 mm的阴极,间隙内流场均匀性和可达性更好;(2)根据等流程原则调整出液缝位置并设计引流槽结构后,叶片边缘的局部缺液现象得到有效改善。开展了3种不同出液缝宽度下的闭式叶环开槽电解加工试验,结果表明,采用优化流场结构的阴极可以实现叶环开槽的稳定加工,工具阴极与工件间的相对进给速度由0.79 mm/min提升至0.98 mm/min;且通道表面质量相对最优,叶背粗糙度由2.681μm降低至1.641μm,叶盆粗糙度由2.482μm降低至1.243μm。验证了流动方式的有效性和流场仿真结果的正确性。

基于无人机数字近景摄影测量的服役边坡监测方法

针对现有边坡变形监测技术自动化与智能化程度低及安设复杂且对边坡有损坏等问题,提出一种基于无人机数字近景摄影测量的服役边坡坡表变形监测方法。根据数字近景摄影测量的相关理论,确定了数码相机内参数标定和监测点坐标解算方法,研制出一种可布设在服役边坡坡表的数字近景摄影测量和全站仪测量通用的变形监测目标物,实现对边坡的联合监测。研究结果表明,数字近景摄影测量技术配合专门设计的变形监测目标物对边坡坡表变形较为敏感,第一期和第二期的监测点位中误差分别为3.3 mm和1.7 mm,水平位移监测的点位和垂直位移监测的高程中误差分别为3.5 mm和1.6 mm,达到毫米级的监测精度,满足滑坡监测标准的精度要求;同时变形监测目标物制作可靠、成本低廉,具有较高的应用价值。

浅埋近距离煤层群上覆采空区火灾及气体下泄防治研究

针对沙坪煤矿13103工作面浅埋近距离煤层上覆采空区煤层自燃和气体下泄问题,综合利用地面红外探测和同位素测氡等多种方法探测13103工作面上覆采空区自然发火状态,在此基础上用SF6气体进行漏风通道测定,并采用数值模拟方法分析了CO气体的下泄机理。研究结果表明:煤层自燃倾向性、复杂埋藏条件和老窑火区是发生煤层自燃的主要原因,在标定12个火区中心点和39 077 m2隐患区域基础上,发现地面、采空区火区和工作面三者裂隙相互连接是导致CO气体在工作面后半部分涌入工作面并在回风隅角处聚集的主要原因。同时,研究发现,采用井上下联防联控手段可消除上覆采空区内高温点,使得CO气体浓度稳定在0.05%以下,有效控制了采空区自燃和气体下泄问题,保障了13103工作面安全生产。

基于时序InSAR的关闭矿井地表残余沉降监测

矿井关闭后,由于受到岩体之间应力和地下水等诸多因素的影响,导致矿区地下岩层和土层的结构发生变化,从而在采空区的地表上造成了二次形态的改变。为探寻矿井关闭后地表形变的规律,采用SBAS-InSAR(Small Baselines Subset InSAR)技术,对影像数据处理后,得到了淮北市海孜矿区关闭矿井5.5 a的地表形变信息。通过影像结果分析,该矿区有2处较为明显的下沉区域,分别分布于矿区东部和西南部,最大下沉速率为25 mm/a,最大下沉量为124 mm,根据以往学者对关闭矿井地区残余下沉的研究,推测其下沉原因可能与煤层采深、地下水汇集破坏煤岩柱以及地表积水等因素有关,同时矿区中部区域发生明显抬升,多集中于祁集镇及周边范围,最大抬升速率为18 mm/a,最大抬升量为133 mm,推测抬升原因可能与地下水回升和建筑物的重力加载有关,推测地下水涌入居民区地下,造成裂隙岩体反弹,而建筑物重力加速了这一过程,则建筑物集中地区抬升越明显。矿区下沉区域约4 a后地表沉降趋于稳定,居民区地表经历先下沉后抬升逐渐趋于稳定。笔者从地表形变最显著区域选取特征点,结合煤层深度、地下水和建筑物重力等因素进行更加详细地分析,根据形变特征将地表形变随时间变化分为3个阶段:残余下沉阶段、相对稳定阶段和抬升阶段;再根据矿区内地表的年形变面积变化得出:监测时间内,矿区大体上抬升面积逐年增加,下沉面积的比重逐渐减小,从而推测矿区抬升区域已达到最大抬升量,但抬升范围将会进一步扩大。