This paper presents a geometrical representation of robot grasping and a definition of "relative form closure" of point contact restraint based on the concepts of positive linear combination,affine combination,convex combination,etc.in the screw space.The dual equivalence theorem,topological equivalence theorem and algebraic equivalence theorem are derived from the defined restraint cone and freedom cone in the dual screw spaces.A J0-function method of computer-aided grasp planning is implemented more efficiently than other proposed methods.The states of restraint and instantaneous motion of a rigid body grasped by a set of point contacts are specified by the unisense degrees of freedom and unisense degrees of restraint.Finally,a quality measure of robot grasping is provided for the synthesis procedure of relatively form-closed grasp.
{"title":"Theory of Point Contact Restraint and Qualitative Analysis of Robot Grasping","authors":"Xiong Wei-Lun","doi":"10.1360/YA1994-37-5-629","DOIUrl":"https://doi.org/10.1360/YA1994-37-5-629","url":null,"abstract":"This paper presents a geometrical representation of robot grasping and a definition of \"relative form closure\" of point contact restraint based on the concepts of positive linear combination,affine combination,convex combination,etc.in the screw space.The dual equivalence theorem,topological equivalence theorem and algebraic equivalence theorem are derived from the defined restraint cone and freedom cone in the dual screw spaces.A J0-function method of computer-aided grasp planning is implemented more efficiently than other proposed methods.The states of restraint and instantaneous motion of a rigid body grasped by a set of point contacts are specified by the unisense degrees of freedom and unisense degrees of restraint.Finally,a quality measure of robot grasping is provided for the synthesis procedure of relatively form-closed grasp.","PeriodicalId":256661,"journal":{"name":"Science in China Series A-Mathematics, Physics, Astronomy & Technological Science","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115057723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The forward extrusion through cone-shaped die,which is the basis for establishing the extrusion theory,can be simply considered to be two-dimensional in a spherical coordinates system in its treatment.This paper,for the first time,derives the analytical formulae and constraint equations for strain,strain-rate and stress of superplastic extrusions through cone-shaped die by simulating displacement function.In the present work,typical superplastic alloy Zn-5wt%Al was chosen as the example,so the results are of universal significance.The method can even be generalized to non-typical superplastic materials.
{"title":"Analytical Theory of Superplastic Extrusion","authors":"Song Yu-quan","doi":"10.1360/YA1994-37-5-607","DOIUrl":"https://doi.org/10.1360/YA1994-37-5-607","url":null,"abstract":"The forward extrusion through cone-shaped die,which is the basis for establishing the extrusion theory,can be simply considered to be two-dimensional in a spherical coordinates system in its treatment.This paper,for the first time,derives the analytical formulae and constraint equations for strain,strain-rate and stress of superplastic extrusions through cone-shaped die by simulating displacement function.In the present work,typical superplastic alloy Zn-5wt%Al was chosen as the example,so the results are of universal significance.The method can even be generalized to non-typical superplastic materials.","PeriodicalId":256661,"journal":{"name":"Science in China Series A-Mathematics, Physics, Astronomy & Technological Science","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116976362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present paper derives the modified expression of broad emission line profiles for the kinematic model of radiation pressure driving BLR gas outflow in the BLR, and discusses the intrinsic emission difference between the two lines HeIλ5876 and Hβ. It is shown that the fact that the observed line width of HeIλ5876 is broader than that of Hβ cannot be explained by W. G. Mathews' modified model. For comparison, line profiles of gravitational infall model and orbital disk model are also calculated; the latter is in good agreement with the observations. Thereupon, conclusion is reached that gravitational infall is an important process in the BLR gas motion.
本文导出了BLR内辐射压力驱动气体流出的运动模型的广义发射谱线的修正表达式，并讨论了HeIλ5876和Hβ两条谱线的本征发射差。结果表明，HeIλ5876观测到的谱线宽度比Hβ谱线宽这一事实不能用W. G. Mathews的修正模型来解释。为了比较，还计算了引力落模型和轨道盘模型的线轮廓;后者与观测结果非常吻合。由此得出结论:引力落体是BLR气体运动的一个重要过程。
{"title":"Kinematic Models of BLR Gas and Line Profiles of HeIλ5876 and Hβ in AGNs","authors":"S. Xue, F. Cheng, J. Kwan","doi":"10.1360/YA1994-37-4-487","DOIUrl":"https://doi.org/10.1360/YA1994-37-4-487","url":null,"abstract":"The present paper derives the modified expression of broad emission line profiles for the kinematic model of radiation pressure driving BLR gas outflow in the BLR, and discusses the intrinsic emission difference between the two lines HeIλ5876 and Hβ. It is shown that the fact that the observed line width of HeIλ5876 is broader than that of Hβ cannot be explained by W. G. Mathews' modified model. For comparison, line profiles of gravitational infall model and orbital disk model are also calculated; the latter is in good agreement with the observations. Thereupon, conclusion is reached that gravitational infall is an important process in the BLR gas motion.","PeriodicalId":256661,"journal":{"name":"Science in China Series A-Mathematics, Physics, Astronomy & Technological Science","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130890800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The encryption algorithm of finite automata (FA) public key cryptosystem is implemented by a weakly invertible finite automata (WIFA) which is composed of a nonlinear WIFA with delay 0 and a linear WIFA with delay τ. In this paper, we proved that such an automaton bears the same properties as the linear WIFA and the increasing ranks of the latter are key factors to affecting the former. A probabilistic algorithm is given to realize a ciphertext attack, and its complexity is analysed through the increasing ranks of the linear WIFA. The size of the parameters for safe linear WIFA is estimated.
{"title":"Increasing Ranks of Linear Finite Automata and Complexity of FA Public Key Cryptosystem","authors":"Feng Bao","doi":"10.1360/YA1994-37-4-504","DOIUrl":"https://doi.org/10.1360/YA1994-37-4-504","url":null,"abstract":"The encryption algorithm of finite automata (FA) public key cryptosystem is implemented by a weakly invertible finite automata (WIFA) which is composed of a nonlinear WIFA with delay 0 and a linear WIFA with delay τ. In this paper, we proved that such an automaton bears the same properties as the linear WIFA and the increasing ranks of the latter are key factors to affecting the former. A probabilistic algorithm is given to realize a ciphertext attack, and its complexity is analysed through the increasing ranks of the linear WIFA. The size of the parameters for safe linear WIFA is estimated.","PeriodicalId":256661,"journal":{"name":"Science in China Series A-Mathematics, Physics, Astronomy & Technological Science","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122928012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hong Huang, Chen Gong-Zheng, Chen Ju-li, Yang Shilin
The positive or negative photoconductivity effects are found between the component of phthalocyanine dimixing composites and the photoconductivity by dimixing method. The relations between the crystalline forms and electronic structure of the composites and the photoconductivity are further studied through X-ray and XPS. The results indicate that the composites may be a kind of new uniform eutectic composites, which can enhance or reduce the partial charge transfer processes from phthalocyanine rings to metals, and the processes are exactly correspondent with the positive or negative photoconductivity effects. A model of gradually transferred charge in the phthalocyanine solids is put forward, which can better explain the electronic processes in the phthalocyanine solids.
{"title":"Electronic Processes in Phthalocyanine Solids","authors":"Hong Huang, Chen Gong-Zheng, Chen Ju-li, Yang Shilin","doi":"10.1360/YA1994-37-4-497","DOIUrl":"https://doi.org/10.1360/YA1994-37-4-497","url":null,"abstract":"The positive or negative photoconductivity effects are found between the component of phthalocyanine dimixing composites and the photoconductivity by dimixing method. The relations between the crystalline forms and electronic structure of the composites and the photoconductivity are further studied through X-ray and XPS. The results indicate that the composites may be a kind of new uniform eutectic composites, which can enhance or reduce the partial charge transfer processes from phthalocyanine rings to metals, and the processes are exactly correspondent with the positive or negative photoconductivity effects. A model of gradually transferred charge in the phthalocyanine solids is put forward, which can better explain the electronic processes in the phthalocyanine solids.","PeriodicalId":256661,"journal":{"name":"Science in China Series A-Mathematics, Physics, Astronomy & Technological Science","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131037389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"W 1, p ( Ω )空间中非强制变分问题的Γ-收敛","authors":"简怀玉","doi":"10.1360/ZA1994-24-3-233","DOIUrl":"https://doi.org/10.1360/ZA1994-24-3-233","url":null,"abstract":"本文研究了泛函∫Ωｆ（ｘ／e，△ｕ）ｄｘ在向量值Ｓｏｂｏｌｅｖ空间中关于其弱拓扑的Г－收敛问题。通过灵活地结合研究Г－收敛的各种不同方法，构造出一种新型的表达式，克服了ｆ（ｙ，λ）不满足强制性条件的困难。","PeriodicalId":256661,"journal":{"name":"Science in China Series A-Mathematics, Physics, Astronomy & Technological Science","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124454279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The time series of the length of day (LOD) and the observational Pacific sea level during l962.0-1990.0 are used to study the relation between Earth rotation and equatorial oceanic activities.The results show that (i) the sea level is apparently rising at an average rate of about 1.75±.01mm/a during the past 30 years,(ii) there are large-scale eastward and westward water motions in the upper equatorial Pacific zone,which,according to the dynamical analysis of the angular momentum of the large-scale sea water motion in Pacific Ocean related to the Earth rotation axis accounts for about 30% of the change in ititerannual Eatlh rotation rate; (iii) the interannual changes in Earth rotation also cause changes in the distribution of the water mass in equatorial Pacific,and affect the formation of ENSO events.Based on these results,we give a new model for the interaction between equatorial ocean and Earth rotation.
{"title":"Relation Between Equatorial Oceanic Activities and LOD Changes","authors":"D. Zheng, Gang. Chen","doi":"10.1360/YA1994-37-3-341","DOIUrl":"https://doi.org/10.1360/YA1994-37-3-341","url":null,"abstract":"The time series of the length of day (LOD) and the observational Pacific sea level during l962.0-1990.0 are used to study the relation between Earth rotation and equatorial oceanic activities.The results show that (i) the sea level is apparently rising at an average rate of about 1.75±.01mm/a during the past 30 years,(ii) there are large-scale eastward and westward water motions in the upper equatorial Pacific zone,which,according to the dynamical analysis of the angular momentum of the large-scale sea water motion in Pacific Ocean related to the Earth rotation axis accounts for about 30% of the change in ititerannual Eatlh rotation rate; (iii) the interannual changes in Earth rotation also cause changes in the distribution of the water mass in equatorial Pacific,and affect the formation of ENSO events.Based on these results,we give a new model for the interaction between equatorial ocean and Earth rotation.","PeriodicalId":256661,"journal":{"name":"Science in China Series A-Mathematics, Physics, Astronomy & Technological Science","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128152168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the present paper,based upon the statistical vorticity structure theory of homogeneous isotropic turbulence,it is proposed that homogeneous isotropic turbulence has the property of similarity in the period of decay,and the similarity-length is determined by the magnitude of velocity fluctuation and the generalized Taylor's microscale of turbulence which is closely related to the characteristic length of the vortex Introducing the condition of pseudo-similarity,this paper starts from the Navier-Stokes equations of motion to study homogeneous isotropic turbulence.In the calculations,the velocity fluctuation is assumed to be periodic in space with the period being proportional to the generalized Taylor's microscale of turbulence The calculations in the physical space are transformed to that in the spectral space by expanding the velocity fluctuation and other physical quantities into Fourier series.Utilizing the fast Fourier transform,the forward difference formulae and the leap-frog difference foumulae,we study the homogeneous isotropic turbulence in the whole period of decay for the different grid Reynolds numbers.Agreements between the calculations and the experimental data are satisfactory.
{"title":"Statistical Theory of Homogeneous Isotropic Turbulence for Incompressible Fluids","authors":"Wang Xiao-hong, H. Yongnian, Zhou Pei-yuan","doi":"10.1360/YA1994-37-2-209","DOIUrl":"https://doi.org/10.1360/YA1994-37-2-209","url":null,"abstract":"In the present paper,based upon the statistical vorticity structure theory of homogeneous isotropic turbulence,it is proposed that homogeneous isotropic turbulence has the property of similarity in the period of decay,and the similarity-length is determined by the magnitude of velocity fluctuation and the generalized Taylor's microscale of turbulence which is closely related to the characteristic length of the vortex Introducing the condition of pseudo-similarity,this paper starts from the Navier-Stokes equations of motion to study homogeneous isotropic turbulence.In the calculations,the velocity fluctuation is assumed to be periodic in space with the period being proportional to the generalized Taylor's microscale of turbulence The calculations in the physical space are transformed to that in the spectral space by expanding the velocity fluctuation and other physical quantities into Fourier series.Utilizing the fast Fourier transform,the forward difference formulae and the leap-frog difference foumulae,we study the homogeneous isotropic turbulence in the whole period of decay for the different grid Reynolds numbers.Agreements between the calculations and the experimental data are satisfactory.","PeriodicalId":256661,"journal":{"name":"Science in China Series A-Mathematics, Physics, Astronomy & Technological Science","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122760653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A kind of infinite demensional nonlinear dynamical system described by functional differential equations with finite time delay is investigated in this paper The comparison principles of LRC type are established and applied to the problems of averaging principle and practical stability in terms of two measures for the system with time delay
{"title":"Comparison Principles in Nonlinear Mechanics and Their Application","authors":"Wang Zhao-lin, Chu Tian-A","doi":"10.1360/YA1994-37-2-186","DOIUrl":"https://doi.org/10.1360/YA1994-37-2-186","url":null,"abstract":"A kind of infinite demensional nonlinear dynamical system described by functional differential equations with finite time delay is investigated in this paper The comparison principles of LRC type are established and applied to the problems of averaging principle and practical stability in terms of two measures for the system with time delay","PeriodicalId":256661,"journal":{"name":"Science in China Series A-Mathematics, Physics, Astronomy & Technological Science","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117033491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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