首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 156 毫秒
1.
张学龙 《大学物理》1991,10(8):24-25
本文给出质心系Runge—Lenz矢量的一种合适的定义形式及其物理含义.作为这种矢量应用的一个实例,我们利用它十分简便地得到考虑原子核运动时原子中电子椭圆形经典轨道方程及有关的结论.  相似文献   

2.
利用微分几何与矢量极限的方法及坐标系间的关联推导了常见曲线坐标系中单位矢量的空间导数.推导过程简洁直观,便于理解,方便在物理教学及实践中运用.  相似文献   

3.
卢端华 《大学物理》2012,31(6):7-12
本文试图从微分几何的角度探讨矢量微分算符▽在各种正交坐标系的梯度、散度、旋度和拉普拉斯符中的不变形式;并探讨了运用▽算符时容易出现混乱的根源,提出了‘括弧矢量优先’的判断与解决方法.从而扫除了运用▽算符的若干障碍.  相似文献   

4.
直接利用矢量解法求解开普勒问题,不必借助于比奈方程.该方法简明扼要,物理图像清晰.  相似文献   

5.
提出把二维矢量表示成极坐标式,能把矢量的大小和方向同时表示出来的概念.通过举例说明在矢量合成或分解的计算公式中,把各矢量用极坐标式的数值代入计算,对列和解矢量方程,都会带来极大方便,是矢量合成的快速计算法.  相似文献   

6.
柳闻鹃 《物理通报》2001,(12):12-13
1 引言 《物理通报》1993年第9期刊登了《自然坐标系单位矢量的正向选取》,该文从微分几何角度引入了自然坐标系单位矢量正向的选取方法为:a.切向坐标轴正向τ°的选取:沿轨道曲线的切线,并指向弧坐标的正方向.  相似文献   

7.
本文简要地说明了矢量势平方项在经典电动力学过程和量子力学过程中的作用,特别地说明了矢量势平方项在原子多光子电离过程中的作用。  相似文献   

8.
本文将力学中角动量矢量的规则进动的概念拓展到任意数学或物理矢量之上;给出了一个任意矢量发生规则进动的判定法则及若干性质,简要证明并枚举数例。  相似文献   

9.
王杰文 《大学物理》1990,(5):46-46,27
在球坐标(r,θ,)中计算矢量的变化率,例如计算质点的加速度,需要先计算基底矢量er,eθ,e的微分der ,deθ,de,本文给出这三个微分.  相似文献   

10.
四维速度矢量在狭义相对论中具有承前启后的作用,一方面关联着光速不变原理决定的相对论四维时空,另一方面关联着相对性原理决定的协变力学定律和电动力学定律.长期的教学实践表明,重视和加强四维速度矢量及其承前启后作用的教学,可以更有效启发初学者理解狭义相对论的来龙去脉和理论体系,更有利于促进他们夯实物理基础.  相似文献   

11.
We propose a model where a condensate of monopole-antimonopole pairs leads to confinement. Magnetic monopoles are considered as massless fermion fields interacting via local four-monopole interaction of the Nambu-Jona-Lasinio kind leading to monopole condensation. Condensation of magnetic monopole currents and any derivative of them are obtained. It is shown that the bosonized version of this Monopole Nambu-Jona- Lasinio (MNJL) model is reducing to London’s theory of dual superconductivity within Dirac’s extension of Maxwell’s Electrodynamics. The affinity of the MNJL-model with Compact Quantum Electrodynamics is discussed.  相似文献   

12.
With displacement, time, and force as basic undefined physical quantities, other physical quantities are defined as combinations of two vector quantities and one scalar quantity. Combinations include multiplication and division of vectors by vectors, scalars by vectors, and scalars by scalars. Defined quantities are vectors, scalars or quaternions, depending on directions of vectors in the definitions. Division of a vector by a vector is equivalent to multiplication of vectors divided by a scalar. The unit of a vector (or scalar) is itself a vector (or scalar) quantity. Thesquare meter (a vector) differs from meter 2 (a scalar), and the cubic meter (a scalar) is different frommeter 3 . The characteristics of displacement, time, and force are considered known from experience.  相似文献   

13.
结合相位恢复和像素行、列循环移动置乱技术, 本文提出了一种基于复振幅场信息复用和RSA算法的非对称多幅图像认证方法, 通过菲涅耳域的相位恢复算法, 依次恢复并生成多幅图像各自所对应的输入平面的复振幅信息, 通过各自的行、列向量随机数对原始二值振幅模板进行行、列循环移动置乱操作来获得每幅图像的采样模板, 认证系统将多个复振幅场信息采样、叠加并空间复用, 同时, 行向量随机数和列向量随机数被RSA算法公钥编码成密文. 系统认证时, 认证方利用自己持有的私钥将密文解码成行向量随机数和列向量随机数, 通过行、列循环移动置乱变换后获得各自的采样模板, 合成的复振幅信息和采样模板等认证信息均放置在各自正确位置, 当认证系统被正确波长的平面波照射时, 在输出平面能获得输出图像, 通过计算、显示输出图像和对应认证图像的非线性相关系数峰值来判断认证是否成功.  相似文献   

14.
A new formalism of the nuclear many-body problem is established in which one ean work with various physical state vector spaces consisting of both Fermions and Bosons, all being equivalent to the original one consisting only of Fermions.With the help of the usual commutation relations and anticommutation relations between the annihilation and creation operators of Boson and Fermion, a generalized state vector space is established, which contains all the physical spaces each being equivalent to the original physical space in terms of pure Fermion operators. Transformation between the state vectors in various equivalent physical spaces are constructed. Basic operators in the original state space are transformed into effective operators in the new physical spaces.  相似文献   

15.
Finding (conformal) Killing vectors of a given metric can be a difficult task. This paper presents an efficient technique for finding Killing, homothetic, or even proper conformal Killing vectors in the Newman-Penrose (NP) formalism. Leaning on, and extending, results previously derived in the GHP formalism we show that the (conformal) Killing equations can be replaced by a set of equations involving the commutators of the Lie derivative with the four NP differential operators, applied to the four coordinates.It is crucial that these operators refer to a preferred tetrad relative to the (conformal) Killing vectors, a notion to be defined. The equations can then be readily solved for the Lie derivative of the coordinates, i.e. for the components of the (conformal) Killing vectors. Some of these equations become trivial if some coordinates are chosen intrinsically (where possible), i.e. if they are somehow tied to the Riemann tensor and its covariant derivatives.If part of the tetrad, i.e. part of null directions and gauge, can be defined intrinsically then that part is generally preferred relative to any Killing vector. This is also true relative to a homothetic vector or a proper conformal Killing vector provided we make a further restriction on that intrinsic part of the tetrad. If because of null isotropy or gauge isotropy, where part of the tetrad cannot even in principle be defined intrinsically, the tetrad is defined only up to (usually) one null rotation parameter and/or a gauge factor, then the NP-Lie equations become slightly more involved and must be solved for the Lie derivative of the null rotation parameter and/or of the gauge factor as well. However, the general method remains the same and is still much more efficient than conventional methods.Several explicit examples are given to illustrate the method.  相似文献   

16.
17.
Regarding phase space—time as a physical space for quantum matter particles, the wave equations are considered in the cases of scalar, vector, and spinor fields. Electrodynamics in pulsed space—time does not contain singularities in the force fields. Expressions are found for the particle propagators in momentum subspace. Order-of-magnitude estimates of force-wave emission and absorption for atomic and nuclear structures show that force waves cannot be neglected in nuclear processes. Force waves are not emitted by particles in a constant force field; the rate of emission is proportional to the square of the rate of force variation over time.NIIVTs Research Center, M. V. Lomosov Moscow State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 32–39, July, 1994.  相似文献   

18.
We assume the existence of a conserved current which generates locally gauge transformations of first kind. We are working in a local quantum Field Theory, where the fields are defined on a vector space where indefinite metric is allowed. We show that the Maxwell equations are not consistent with the above assumptions and the vectors obtained by applying local charged operators on the vacuum cannot describe physical states. Moreover we show that, if charged fields have non-trivial expectation value on the physical states, the vector space must contain vectors with negative norm. We discuss the relation between the local formulation of QED and a formulation in terms of physical states. As an example we study the transition from Gupta-Bleuler free QED to the Coulomb-gauge formulation.  相似文献   

19.
An intuitive, generic, physical model, or conceptual paradigm for pilot wave steerage of particle beams based on Stochastic Electrodynamics is presented. The utility of this model for understanding the Pauli Exclusion Principle is briefly considered, and a possible experimental verification for the underlying concepts is proposed.  相似文献   

20.
光谱解混是高光谱技术中的关键部分,对地物成分的定量分析至关重要。线性光谱解混方法在计算端元丰度时,大多需要涉及矩阵求逆或方阵行列式的计算,导致软件实现的计算复杂度高,且硬件实现困难。同时,当端元数量增加时,算法的计算量也会随之呈指数级快速增长。论文基于传统的正交子空间投影方法,利用正交原理,提出了一种新的光谱解混方法——正交向量投影。该方法首先利用Gram-Schmidt过程计算每个端元的最终正交向量分量,并将其作为代表端元的投影向量。然后对于任意的待解混光谱向量,直接将其投影到该正交向量上。最后,计算得到投影分量的长度与正交向量的长度比,即为该正交向量所代表端元的无约束丰度。该过程避免了正交子空间投影和最小方差方法中计算复杂、实现困难的矩阵求逆运算,更便于并行计算的设计和硬件实现。通过理论的推导分析,证明了该算法与正交子空间投影和最小方差方法是完全一致的。另外,由于算法避免了矩阵相乘和求逆运算,简化了解混过程,通过对不同算法复杂度的具体分析,也证明该算法相对其他算法可以对端元数量降低一个量级。最后,在模拟数据和实际图像上分别进行实验测试,结果的分析和比较,也说明了算法的有效性。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号