期刊文献+
共找到2,285篇文章
< 1 2 115 >
每页显示 20 50 100
A solution method for decomposing vector fields in Hamilton energy
1
作者 Xin Zhao Ming Yi +2 位作者 Zhou-Chao Wei Yuan Zhu Lu-Lu Lu 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第9期645-653,共9页
Hamilton energy,which reflects the energy variation of systems,is one of the crucial instruments used to analyze the characteristics of dynamical systems.Here we propose a method to deduce Hamilton energy based on the... Hamilton energy,which reflects the energy variation of systems,is one of the crucial instruments used to analyze the characteristics of dynamical systems.Here we propose a method to deduce Hamilton energy based on the existing systems.This derivation process consists of three steps:step 1,decomposing the vector field;step 2,solving the Hamilton energy function;and step 3,verifying uniqueness.In order to easily choose an appropriate decomposition method,we propose a classification criterion based on the form of system state variables,i.e.,type-I vector fields that can be directly decomposed and type-II vector fields decomposed via exterior differentiation.Moreover,exterior differentiation is used to represent the curl of low-high dimension vector fields in the process of decomposition.Finally,we exemplify the Hamilton energy function of six classical systems and analyze the relationship between Hamilton energy and dynamic behavior.This solution provides a new approach for deducing the Hamilton energy function,especially in high-dimensional systems. 展开更多
关键词 Hamilton energy dynamical systems vector field exterior differentiation
下载PDF
Vector magnetometry in zero bias magnetic field using nitrogen-vacancy ensembles
2
作者 Chunxing Li Fa-Zhan Shi +1 位作者 Jingwei Zhou Peng-Fei Wang 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第10期21-29,共9页
The application of the vector magnetometry based on nitrogen-vacancy(NV)ensembles has been widely investigatedin multiple areas.It has the superiority of high sensitivity and high stability in ambient conditions with ... The application of the vector magnetometry based on nitrogen-vacancy(NV)ensembles has been widely investigatedin multiple areas.It has the superiority of high sensitivity and high stability in ambient conditions with microscale spatialresolution.However,a bias magnetic field is necessary to fully separate the resonance lines of optically detected magneticresonance(ODMR)spectrum of NV ensembles.This brings disturbances in samples being detected and limits the rangeof application.Here,we demonstrate a method of vector magnetometry in zero bias magnetic field using NV ensembles.By utilizing the anisotropy property of fluorescence excited from NV centers,we analyzed the ODMR spectrum of NVensembles under various polarized angles of excitation laser in zero bias magnetic field with a quantitative numerical modeland reconstructed the magnetic field vector.The minimum magnetic field modulus that can be resolved accurately is downto~0.64 G theoretically depending on the ODMR spectral line width(1.8 MHz),and~2 G experimentally due to noisesin fluorescence signals and errors in calibration.By using 13C purified and low nitrogen concentration diamond combinedwith improving calibration of unknown parameters,the ODMR spectral line width can be further decreased below 0.5 MHz,corresponding to~0.18 G minimum resolvable magnetic field modulus. 展开更多
关键词 vector magnetometry NV ensembles optically detected magnetic resonance(ODMR) zero bias magnetic field
下载PDF
Conservative Vector Fields and the Intersect Rule
3
作者 Daniel A. Jaffa 《Journal of Applied Mathematics and Physics》 2023年第10期2888-2903,共16页
This paper covers the concept of a conservative vector field, and its application in vector physics and Newtonian mechanics. Conservative vector fields are defined as the gradient of a scalar-valued potential function... This paper covers the concept of a conservative vector field, and its application in vector physics and Newtonian mechanics. Conservative vector fields are defined as the gradient of a scalar-valued potential function. Gradient fields are irrotational, as in the curl in all conservative vector fields is zero, by Clairaut’s Theorem. Additionally, line integrals in conservative vector fields are path-independent, and line integrals over closed paths are always equal to zero, properties proved by the Gradient Theorem of multivariable calculus. Gradient fields represent conservative forces, and the associated potential function is analogous to potential energy associated with said conservative forces. The Intersect Rule provides a new, unique shortcut for determining if a vector field is conservative and deriving potential functions, by treating the indefinite integral as a set of infinitely many functions which satisfy the integral. 展开更多
关键词 vector Physics vector Calculus Multivariable Calculus Gradient fields vector fields Conservative vector fields Newtonian Mechanics
下载PDF
Hybrid gradient vector fields for path-following guidance
4
作者 Yi-yang Zhao Zhen Yang +4 位作者 Wei-ren Kong Hai-yin Piao Ji-chuan Huang Xiao-feng Lv De-yun Zhou 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第10期165-182,共18页
Guidance path-planning and following are two core technologies used for controlling un-manned aerial vehicles(UAVs)in both military and civilian applications.However,only a few approaches treat both the technologies s... Guidance path-planning and following are two core technologies used for controlling un-manned aerial vehicles(UAVs)in both military and civilian applications.However,only a few approaches treat both the technologies simultaneously.In this study,an innovative hybrid gradient vector fields for path-following guidance(HGVFs-PFG)algorithm is proposed to control fixed-wing UAVs to follow a generated guidance path and oriented target curves in three-dimensional space,which can be any combination of straight lines,arcs,and helixes as motion primitives.The algorithm aids the creation of vector fields(VFs)for these motion primitives as well as the design of an effective switching strategy to ensure that only one VF is activated at any time to ensure that the complex paths are followed completely.The strategies designed in earlier studies have flaws that prevent the UAV from following arcs that make its turning angle too large.The proposed switching strategy solves this problem by introducing the concept of the virtual way-points.Finally,the performance of the HGVFs-PFG algorithm is verified using a reducedorder autopilot and four representative simulation scenarios.The simulation considers the constraints of the aircraft,and its results indicate that the algorithm performs well in following both lateral and longitudinal control,particularly for curved paths.In general,the proposed technical method is practical and competitive. 展开更多
关键词 Unmanned aerial vehicle(UAV) Path-following guidance(PFG) Hybrid gradient vector field(HGVF) Switching strategy
下载PDF
Characteristics of electromagnetic vector field generated from rock fracturing 被引量:1
5
作者 Menghan Wei Dazhao Song +3 位作者 Xueqiu He Quan Lou Liming Qiu Zhenlei Li 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第2期457-466,共10页
Rock fracturing is often accompanied by electromagnetic phenomenon.As a vector field,in addition to the intensity that is widely concerned,the generated electromagnetic field also has obvious direction-ality.To this e... Rock fracturing is often accompanied by electromagnetic phenomenon.As a vector field,in addition to the intensity that is widely concerned,the generated electromagnetic field also has obvious direction-ality.To this end,a set of electromagnetic antennas capable of simultaneous three-axis measurement is used to monitor the electromagnetic vector field generated from rock fracturing based on Brazilian tests.The signal amplitude on each axis can represent the magnitude of actual magnetic flux density component on the three axes.The intensity and directional characteristics of electromagnetic signals received at different positions are studied using vector synthesis.The directionality of electromagnetic radiation measured using a three-axis electromagnetic antenna shows that the direction of the magnetic flux intensity generated by rock fracturing tends to be parallel to the crack surface,and the measured signal intensity is greater in a direction closer to the crack surface. 展开更多
关键词 Electromagnetic radiation DIRECTIONALITY vector field Rock fracturing
下载PDF
THE INVARIANT CLOSED CONES OF HOMOGENEOUS VECTOR FIELDS OF DEGREE TWO IN R^(3) 被引量:1
6
作者 梁肇军 《Acta Mathematica Scientia》 SCIE CSCD 2001年第1期29-36,共8页
In this paper, the authors investigate the invariant cones of quadratic homoge- neous polynomial vector fields in three variables. Necessary and sufficient conditions for the existence of non-isolated invariant closed... In this paper, the authors investigate the invariant cones of quadratic homoge- neous polynomial vector fields in three variables. Necessary and sufficient conditions for the existence of non-isolated invariant closed cones are obtained by the algebraic expressions in terms of the coefficients of certain quadratic homogeneous polynomials. 展开更多
关键词 Homogeneous vector field invariant cone
下载PDF
EMBEDDING THEOREMS ON CAMPANATO-MORREY SPACES FOR VECTOR FIELDS OF HoRMANDER TYPE 被引量:3
7
作者 Guozhen Lu (Wright State University, USA) 《Analysis in Theory and Applications》 1998年第1期69-80,共12页
This paper deals with embedding theorems on Campanato-Marrey spaces formed by degenerate vector fields, which include Honnander and Grushin type of vector fields. These embedding theorems are somewhat different from t... This paper deals with embedding theorems on Campanato-Marrey spaces formed by degenerate vector fields, which include Honnander and Grushin type of vector fields. These embedding theorems are somewhat different from the known Poincare estimates. The main ingredients of the proofs rely on the fractional maximal functions. These results evidently have applications to the regularity of subelliptic PDE. 展开更多
关键词 EMBEDDING THEOREMS ON CAMPANATO-MORREY SPACES FOR vector fields OF HoRMANDER TYPE MATH
下载PDF
VECTOR FIELDS FOR CONTACT PAIRS
8
作者 Yue HE Hai-Long HER 《Acta Mathematica Scientia》 SCIE CSCD 2019年第4期1081-1088,共8页
Let M be a(2 k + 2 l + 2)-dimensional smooth manifold. For such M, Bande and Hadjar introduce a new geometric structure called contact pair which roughly is a couple of 1-forms of constant classes with complementary k... Let M be a(2 k + 2 l + 2)-dimensional smooth manifold. For such M, Bande and Hadjar introduce a new geometric structure called contact pair which roughly is a couple of 1-forms of constant classes with complementary kernels and foliations. We show the relationship between a pair of vector fields for a contact pair and a quadruple of functions on M. This is a generalization of the classical result for contact manifolds. 展开更多
关键词 CONTACT GEOMETRY Reeb vector field CONTACT PAIR
下载PDF
Projective vector fields on Finsler manifolds
9
作者 TIAN Huang-jia 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2014年第2期217-229,共13页
In this paper, we give the equation that characterizes projective vector fields on a Finsler manifold by the local coordinate. Moreover, we obtain a feature of the projective fields on the compact Finsler manifold wit... In this paper, we give the equation that characterizes projective vector fields on a Finsler manifold by the local coordinate. Moreover, we obtain a feature of the projective fields on the compact Finsler manifold with non-positive flag curvature and the non-existence of projective vector fields on the compact Finsler manifold with negative flag curvature. Furthermore, we deduce some expectable, but non-trivial relationships between geometric vector fields such as projective, affine, conformal, homothetic and Killing vector fields on a Finsler manifold. 展开更多
关键词 Finsler manifold projective vector field conformal vector field.
下载PDF
THE VECTOR FIELDS ADMITTING ONE-PARAMETER SPATIAL SYMMETRY GROUP AND THEIR REDUCTION
10
作者 黄德斌 赵晓华 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2000年第2期173-180,共8页
For a n-dimensional vector fields preserving some n-form, the following conclusion is reached by the method of Lie group. That is, if it admits an one-parameter, n-form preserving symmetry group, a transformation inde... For a n-dimensional vector fields preserving some n-form, the following conclusion is reached by the method of Lie group. That is, if it admits an one-parameter, n-form preserving symmetry group, a transformation independent of the vector field is constructed explicitly, which can reduce not only dimesion of the vector field by one, but also make the reduced vector field preserve the corresponding ( n - 1)-form. In partic ular, while n = 3, an important result can be directly got which is given by Me,ie and Wiggins in 1994. 展开更多
关键词 vector field symmtry group Lie group REDUCTION preserving n-form
下载PDF
Some Properties of Homogeneous Vector Fields
11
作者 盛平兴 《Advances in Manufacturing》 SCIE CAS 1997年第3期191-195,共5页
For planar analytic homogcneous vector fields, the existence of periodic orbits and the noncxistence of limit sets arc verilied. It is concluded that spacial analytic homlogencous vector tleld of order in has no limit... For planar analytic homogcneous vector fields, the existence of periodic orbits and the noncxistence of limit sets arc verilied. It is concluded that spacial analytic homlogencous vector tleld of order in has no limit sets for any m>1. Similar results arc extended to highel-dimensional polynomial homogeneous vector fields under certain conditions. 展开更多
关键词 homogeneous vector field induced tangcnt vector held Hairy Ban theorem invariant cone qnalitative analysis closed orbits and limit sets.
下载PDF
<i>L<sub>p</sub></i>-Estimations of Vector Fields in Unbounded Domains
12
作者 Alexey V. Kalinin Alla A. Tyukhtina Artem A. Zhidkov 《Applied Mathematics》 2012年第1期45-51,共7页
Some new estimations of scalar products of vector fields in unbounded domains are investigated. Lp-estimations for the vector fields were proved in special weighted functional spaces. The paper generalizes our earlier... Some new estimations of scalar products of vector fields in unbounded domains are investigated. Lp-estimations for the vector fields were proved in special weighted functional spaces. The paper generalizes our earlier results for bounded domains. Estimations for scalar products make it possible to investigate wide classes of mathematical physics problems in physically inhomogeneous domains. Such estimations allow studying issues of correctness for problems with non-smooth coefficients. The paper analyses solvability of stationary set of Maxwell equations in inhomogeneous unbounded domains based on the proved Lp-estimations. 展开更多
关键词 Estimations SCALAR Product vector field Functional Spaces Maxwell Equations SOLVABILITY Inhomogeneous Domains
下载PDF
Classification of Teleparallel Homothetic Vector Fields in Cylindrically Symmetric Static Space-Times in Teleparallel Theory of Gravitation
13
作者 Ghulam Shabbir Suhail Khan 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第10期675-678,共4页
In this paper we classify cylindrically symmetric static space-times according to their teleparallel homothetic vector fields using direct integration technique. It turns out that the dimensions of the teleparallel ho... In this paper we classify cylindrically symmetric static space-times according to their teleparallel homothetic vector fields using direct integration technique. It turns out that the dimensions of the teleparallel homothetic vector fields are 4, 5, 7 or 11, which are the same in numbers as in general relativity. In case of 4, 5 or 7 proper teleparallel homothetic vector fields exist for the special choice to the space-times. In the case of 11 teleparallel homothetic vector fields the space-time becomes Minkowski with all the zero torsion components. Teleparallel homothetic vector fields in this case are exactly the same as in general relativity. It is important to note that this classification also covers the plane symmetric static space-times. 展开更多
关键词 teleparallel homothetic vector fields WeitzenbSck connections TORSION
下载PDF
A Note on Classification of Spatially Homogeneous Rotating Space-Times According to Their Teleparallel Killing Vector Fields in Teleparallel Theory of Gravitation
14
作者 Ghulam Shabbir Suhail Khan Amjad Ali 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第2期268-272,共5页
In this paper we classify spatially homogeneous rotating space-times according to their teleparallel Killing vector fields using direct integration technique.It turns out that the dimension of the teleparallel Killing... In this paper we classify spatially homogeneous rotating space-times according to their teleparallel Killing vector fields using direct integration technique.It turns out that the dimension of the teleparallel Killing vector fields is 5 or 10.In the case of 10 teleparallel Killing vector fields the space-time becomes Minkowski and all the torsion components are zero.Teleparallel Killing vector fields in this case are exactly the same as in general relativity.In the cases of 5 teleparallel Killing vector fields we get two more conservation laws in the teleparallel theory of gravitation.Here we also discuss some well-known examples of spatially homogeneous rotating space-times according to their teleparallel Killing vector fields. 展开更多
关键词 teleparallel killing vector fields Weitzenbock geometry TORSION
下载PDF
Classification of Kantowski-Sachs and Bianchi Type Ⅲ Space-Times According to Their Killing Vector Fields in Teleparallel Theory of Gravitation
15
作者 Ghulam Shabbir Suhail Khan 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第9期469-472,共4页
In this paper we classify Kantowski-Sachs and Bianchi type Ⅲ space-times according to their teleparallel Killing vector fields using direct integration technique. It turns out that the dimension of the telepaxallel K... In this paper we classify Kantowski-Sachs and Bianchi type Ⅲ space-times according to their teleparallel Killing vector fields using direct integration technique. It turns out that the dimension of the telepaxallel Killing vector fields are 4 or 6, which are the same in numbers as in general relativity. In case of 4 the teleparallel Killing vector fields are multiple of the corresponding Killing vector fields in general relativity by some function of t. In the case of 6 Killing vector fields the metric functions become constants and the Killing vector fields in this case are exactly the same as in general relativity. Here we also discuss the Lie algebra in each case. 展开更多
关键词 teleparallel killing vector fields Weitzenb5ck connections TORSION
下载PDF
Spatial-Variant Geometric Phase of Hybrid-Polarized Vector Optical Fields
16
作者 Yu Si Ling-Jun Kong +5 位作者 Yu Zhang Zhi-Cheng Ren Yue Pan Chenghou Tu Yongnan Li Hui-Tian Wang 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第4期50-54,共5页
We investigate a novel spatial geometric phase of hybrid-polarized vector fields consisting of linear, elliptical and circular polarizations by Young's two-slit interferometer instead of the widely used Mach-Zehnder ... We investigate a novel spatial geometric phase of hybrid-polarized vector fields consisting of linear, elliptical and circular polarizations by Young's two-slit interferometer instead of the widely used Mach-Zehnder interferometer. This spatial geometric phase can be manipulated by engineering the spatial configuration of hybrid polarizations, and is directly related to the topological charge, the local states of polarization and the rotational symmetry of hybrid-polarized vector optical fields. The unique feature of geometric phase has implications in quantum information science as well as other physical systems such as electron vortex beams. 展开更多
关键词 Spatial-Variant Geometric Phase of Hybrid-Polarized vector Optical fields VOF HP
下载PDF
Magnetic Field Curves and Magnetic Equipotential Surfaces around Crossing Electrical Wires Replacing Classical Magnetic Field Lines
17
作者 Geoffroy Auvert 《Open Journal of Applied Sciences》 2024年第8期1996-2008,共13页
This article is based on a recent model specifically defining magnetic field values around electrical wires. With this model, calculations of field around parallel wires were obtained. Now, this model is extended with... This article is based on a recent model specifically defining magnetic field values around electrical wires. With this model, calculations of field around parallel wires were obtained. Now, this model is extended with the new concept of magnetic equipotential surface to magnetic field curves around crossing wires. Cases of single, double, and triple wires are described. Subsequent article will be conducted for more general scenarios where wires are neither infinite nor parallel. 展开更多
关键词 Magnetic field Value Magnetic field vector Magnetic field Line Magnetic field Curve Equipotential Surface Crossing Electrical Wires Magnetic Cross Product
下载PDF
On the Massless Vector Fields in a Rindler Space
18
作者 Roberto Soldati Caterina Specchia 《Journal of Modern Physics》 2015年第12期1743-1755,共13页
We study the quantum theory of the mass-less vector fields on the Rindler space. We evaluate the Bogoliubov coefficients by means of a new technique based upon the use of light-front coordinates and Mellin transform. ... We study the quantum theory of the mass-less vector fields on the Rindler space. We evaluate the Bogoliubov coefficients by means of a new technique based upon the use of light-front coordinates and Mellin transform. We briefly comment about the ensuing Unruh effect and its consequences. 展开更多
关键词 Rindler SPACE Unruh Effect vector fields BOGOLIUBOV COEFFICIENTS
下载PDF
Utilizing Iso-Value Field Curves in Lieu of Magnetic Field Lines Amid Infinite and Parallel Electrical Wires
19
作者 Geoffroy Auvert 《Open Journal of Applied Sciences》 2024年第1期70-84,共15页
Building on a new model proposed recently for calculating constant electro-magnetic field values, the present article explores the electro-magnetic field configuration generated by parallel electrical wires. This impo... Building on a new model proposed recently for calculating constant electro-magnetic field values, the present article explores the electro-magnetic field configuration generated by parallel electrical wires. This imposes a reevaluation of the drawing procedure for constructing field curves with a constant field values around multiple parallel electrical conducting wires. To achieve this, we employ methods akin to those used for creating contours on topographical maps, ensuring a consistent numerical field value along the entire length of the field curves. Subsequent calculations will be conducted for scenarios where wires are not parallel. 展开更多
关键词 Specific field Value Parallel Electrical Wires Magnetic field vector field around Parallel Wires Topographic Level Map
下载PDF
A NOTE ON EQUIVARIANT VECTOR FIELDS
20
作者 姜伯驹 《Acta Mathematica Scientia》 SCIE CSCD 1991年第3期274-282,共9页
1. Introduction. Throughout this note, G is a finite group, M is a compact connected smooth on-dimensional manifold with or without boundary M, and G acts smoothly on M. We follow the standard notations ([B], [tD]). T... 1. Introduction. Throughout this note, G is a finite group, M is a compact connected smooth on-dimensional manifold with or without boundary M, and G acts smoothly on M. We follow the standard notations ([B], [tD]). The isotropy subgroup of a point 展开更多
关键词 A NOTE ON EQUIVARIANT vector fields
下载PDF
上一页 1 2 115 下一页 到第
使用帮助 返回顶部