共查询到20条相似文献，搜索用时 328 毫秒
1.
傅康麟 《昆明师范高等专科学校学报》1987,(4)
在L—LS耦合下,一般地要确定一个原子的基态,必须知道原子系统的自旋角动量,轨道角动量以及由自旋和轨道按L-S耦合而得的总角动量。但是由同一电子组态所形成的可能的原子态有若干个,那末这些原子态中哪个是基态?如何确定?本文将给出在L—S耦合下确定原子基态S,L,T的一种方法。这种方法是借助于一组公式。用此方法确定的原子基态与其它方法确定的完全一样。但这种方法所借助的一组公式具有简单、对称和便於记忆的特点。 相似文献
2.
《赤峰学院学报(自然科学版)》2017,(12)
本文利用求解能量本征方程方法,研究外磁场对氦原子中两电子体系能量的影响,进而研究自旋效应.理论结果表明,若自旋状态在磁场方向的投影为零,则自旋磁矩与外磁场的相互作用能量为零,自旋对体系无影响;反之,若自旋状态在磁场方向的投影不为零,则自旋磁矩与外磁场的相互作用能量不为零,自旋对体系有影响.所以,氦原子处于基态时,自旋对体系无影响;处于激发态时,自旋的影响随自旋状态的不同而不同. 相似文献
3.
在现行的教材中,原子基态的求法,通常是先用L_s耦合法求出基态电子组态所有可能的原子态,再除去违反泡利原理的状态,最后根据洪特定则确定原子的基态。此法繁琐,不易为学生掌握。对此人们作了很多努力,但所得结果仍需考虑次壳层中的电子过半与否和正、倒序关系而不易记忆。本文所导出的关系,可克服上述困难。确定原子态有L_s稠合法,jj耦合法,jk耦合法等。前者适用于轻的、中等质量或低激发态的原子。原子的基态是原子能量最低的状态,故可用L_s耦合法来确定基态原子的原子态。洪特发现:<1>对于L_s耦合,同一电子组态所形成的所有多重态中,总自旋角动量量子数S最大的态能级最低,其中又以总轨道角动量量子数L最大的态能级最低;<2>若次壳层中 相似文献
4.
本文根据自旋平行的两个电子泡利排斥原理,按照洪特定则,运用角动量合成投影规律.对原子基态是等效电子时基态光谱项的研究.并提出原子基态是等效电子时基态光谱项确定的一种简易方法. 相似文献
5.
给出了单电子量子同心环基态能量E(0,0)随磁场和势垒的变化规律,并对变化规律进行分析.结果表明,单电子量子同心环基态能量随磁场增大而增大,由于磁场的存在,原来的基态能级分裂成三个能级.由于量子同心环中势垒的存在,使得单电子量子同心环基态能量增大,基态能量随势垒的增大而增大. 相似文献
6.
曹欣伟 《西安文理学院学报》2004,19(3):68-71
本使用严格对角化方法对S=1／2自旋阶梯模型进行了数值模拟计算研究，通过对不同长度自旋阶梯中两条单链和链间耦合部分各自对基态能量、能隙的贡献比例和自旋关联的考察，认为该系统处于自旋液体状态，同时模拟计算的结果对沿链方向形成交错磁场的假设提出了质疑。 相似文献
7.
利用传递矩阵方法，在同时考虑自旋轨道耦合效应和量子尺寸效应情况下，分别计算了没有外场、外加磁场、电场时，透射概率的变化关系。 相似文献
8.
从经典力学中质点系的角动量导出轨道角动量和自旋角动量的概念,并给出如地球运动的自定轴运动刚体的轨道角动量和自旋角动量,以及一般运动刚体的轨道角动量和自旋角动量. 相似文献
9.
若以P_L、P_s, P_J分别表示原子的总轨道、总自旋角动量和总角动量,L、S、J为其相应的量子数(l为电子的轨道角量子数),洪特发现,对于LS耦合:(1)在给定电子组态时,S最大的态能级最低,其中又以L最大的态能级最低。(2)对于同一L_(max)值而J值不同的能级,当次壳层中同科价电子数A不过半满 相似文献
10.
基于近些年来试验上有机和无机磁性高分子化合物的合成,文章利用双时格林函数方法, 对AB2型双向聚合物棱型自旋链的磁学和热力学性质进行了研究．在半满强耦合极限条件下,该系统可转化为量子铁磁-反铁磁自旋为1／2的AB2型海森堡模型,该模型将由零温量子相转变到亚铁磁基态．在Tyablikov耦合近似条件下,基态的自旋波、以及亚晶格的磁化强度和系统的磁化率在不同的序参量和不同外场的条件下进行了研究．结果显示该模型低温下的性质和自旋为1／2的铁磁相互作用的海森堡链相同． 相似文献
11.
ZHANG Gang YU Lie XIE You-bai School of Electromechanical Engineering Automation Shanghai University Shanghai China Xian Jiaotong University Xian China 《上海大学学报(英文版)》2000,(Z1)
1 IntroductionThe great majority of docUments about magneticbearings dealt only with the characteristics when thejournal was concentric with the radial magnetic bearing inthe past, and few research involved the ones when thejournal was eccotic with the radial magnetic bearing.For example, the bulk of documents suPPosed thecomponents Fx and F. of magnetic force depended onlyon the cUrred in x and y direchons respeGtively, bac theair gap thickness and the curvatUre of suiface shape werenot co… 相似文献
12.
This paper is based on the example of a radial magnetic bearing possessed of eight-pole, and derives the calculation formulas of
static and dynamic mechanical characteristics of the bearing, in which the shape and curvature of surface, eccentricity and tilt of the journal
are taken into account. Variations of the static and dynamic characteristics of the radial magnetic bearing versus static tilt parameters of
journal are discussed. The outcomes show that the static tilt of the journal has influence on the mechanical characteristics of radial magnetic
bearing, and change the static load capacity between two radial magnetic bearings and exert coupling effect between them. To study the
dynamics of a practical rotor-magnetic bearing system, at least six stiffness coefficients in each radial magnetic bearing must be considered
in ideal case, and twelve stiffness coefficients must be considered in general case of tilting journal. Such a find can be used for the coupled
electromechanical dynamics analysis of rotor system equipped with magnetic bearings. 相似文献
13.
The path of charged particles is affected when they enter a magnetic field. This change of path largely depends on the angle between the applied magnetic field and the direction of motion of the charged particle (and its velocity) entering the magnetic field. This is demonstrated by means of a simple, low-cost experiment. A high voltage is used to ionize the air between a spark gap. The flow of charged particles between the spark gap is altered by applying a magnetic field from a rare earth permanent magnet having surface magnetic field induction of 0.12 T. 相似文献
14.
采用线性组合算符及幺正变换的方法研究了量子阱中强耦合磁极化子的性质。得出磁极化子基态能量与耦合强度,阱宽,磁场强度之间的关系。数值计算表明：对于强耦合磁极化子,振动频率随磁场强度的增加而增大。基态能量随回旋频率的增加而增大。磁极化子的基态能量随着阱宽的增大而减小,阱宽越小磁极化子的量子尺寸效应越明显。 相似文献
15.
磁暴期间,导电网络(如电力系统、管道和电话电缆)中会感应出电压。用计算穿过环路的变化垂直磁场或者计算由沿环路变化的水平磁场来得到地面水平环路感应出的电压,这两种方法是等效的,都应用了麦克斯韦方程组,但是它们的等效很难形象化地给予解释。考虑到磁场的发散特性,穿过水平环路的垂直磁场如何相关到环路外围的水平磁场(由于地面线电流),用磁扰动的例子来说明两种方法在计算导电网络中感应电压上是等效的。 相似文献
16.
垂直于液晶胆甾相加磁场可以引起胆甾相-向列相转变。在有界面影响的情况下,建立了物理模型。在连续体理论的基础上考虑到表面能,对有界面的磁致胆甾相-向列相转变进行分析,得到临界磁场,并画出空间周期随外磁场的变化曲线,与没有引入表面能的理论结果进行比较后发现,由于表面能对磁致胆甾相-向列相转变的影响,临界磁场要略小于没有考虑边界的情况,且结果表明盒厚在足够薄的情况下对临界磁场的影响才会明显。 相似文献
17.
祝长生 《浙江大学学报(A卷英文版)》2003,4(5)
A disc-type magneto-rheological fluid damper operating in shear mode is proposed in this paper, which is based on the special characteristics of the magneto-rheological (MR) fluid with rapid, reversible and dramatic change in its rheological properties by the application of an external magnetic field. The magnetic field of the disc-type MR fluid damper is analysed by the finite element method; the controllability of the disc-type MR fluid damper on the dynamic behaviour of a rotor system; and the effectiveness of the disc-type MR fluid damper in controlling the vibration of a rotor system, are studied in a flexible rotor system with an over-hung disc. It is shown that the magnetic flux density of the disc-type MR fluid damper in the working areas can significantly change with the applied current in the coil; and that the dynamic behavior of the disc-type MR fluid damper can be varied by the application of an external magnetic field produced by a low voltage electromagnetic coil. The disc-type MR fluid damper can significantly change the dynamic characteristics of a rotor system, provided that the location of the disk-type MR fluid damper is carefully chosen. The disc-type MR fluid damper is a new actuator with good dynamic characteristics for rotating machinery. 相似文献
18.
李福安 《黄山高等专科学校学报》2014,(3):13-16
利用电弧炉熔炼法分别制备了LaFe11.2Co0.7Si1.1B0.2,LaFe11.1Co0.8Si.iB0.2和LaFe11Co0.9Si1.1B0.2化合物.磁性测量和计算得到该系列化合物的等温磁熵变,利用直接测量法测量该系列化合物在外加磁场为0-1.5T下的绝热温变.最后分别计算基于等温磁熵变和绝热温变的相对制冷能力. 相似文献
19.
Zhu Chang-sheng 《浙江大学学报(A卷英文版)》2003,4(5):514-519
A disc-type magneto-rheological fluid damper operating in shear mode is proposed in this paper, which is based on the special
characteristics of the magneto-rheological (MR) fluid with rapid, reversible and dramatic change in its rheological properties
by the application of an external magnetic field. The magnetic field of the disc-type MR fluid damper is analysed by the finite
element method; the controllability of the disc-type MR fluid damper on the dynamic behaviour of a rotor system; and the effectiveness
of the disc-type MR fluid damper in controlling the vibration of a rotor system, are studied in a flexible rotor system with
an overhung disc. it is shown that the magnetic flux density of the disc-type MR fluid damper in the working areas can significantly
change with the applied current in the coil; and that the dynamic behavior of the disc-type MR fluid damper can be varied
by the application of an external magnetic field produced by a low voltage electromagnetic coil. The disc-type MR fluid damper
can significantly change the dynamic characteristics of a rotor system, provided that the location of the disk-type MR fluid
damper is carefully chosen. The disc-type MR fluid damper is a new actuator with good dynamic characteristics for rotating
machinery.
Project supported partially by the EC BRITE/EURAM program under BRPR-CT97-0544 IMPACT project and State Key Laboratory of
Vibration, Shock and Noise, Shanghai Jiatong University 相似文献
20.
吴强 《武汉工程职业技术学院学报》2020,(1):1-5
在增程器失火-不对中耦合故障下,通过多工况下虚拟样机仿真,对不对中故障的故障诊断特征的变化规律展开了研究。借助虚拟样机平台搭建了某款增程器虚拟样机刚柔混合模型;对已经探索得到的不对中故障诊断特征,在多转速、多失火状态工况下,研究耦合故障下不对中故障特征变化规律;对耦合故障下的增程器转子系统进行动力学分析,结合机理研究,对不对中故障诊断特征的变化进行了原理分析;由此得到耦合故障工况下不对中故障诊断特征变化规律。 相似文献