The definition and the criterion of a unified symmetry for a Hamilton system are presented. The sufficient condition under which the Noether symmetry is a unified symmetry for the system is given. A new conserved quan...The definition and the criterion of a unified symmetry for a Hamilton system are presented. The sufficient condition under which the Noether symmetry is a unified symmetry for the system is given. A new conserved quantity,as well as the Noether conserved quantity and the Hojman conserved quantity, deduced from the unified symmetry, is obtained. An example is finally given to illustrate the application of the results.展开更多
This paper focuses on studying the relation between a velocity-dependent symmetry and a generalized Lutzky conserved quantity for a holonomic system with remainder coordinates subjected to unilateral constraints. The ...This paper focuses on studying the relation between a velocity-dependent symmetry and a generalized Lutzky conserved quantity for a holonomic system with remainder coordinates subjected to unilateral constraints. The differential equations of motion of the system are established, and the definition of Lie symmetry for the system is given. The conditions under which a Lie symmetry can directly lead up to a generalized Lutzky conserved quantity and the form of the new conserved quantity are obtained, and an example is given to illustrate the application of the results.展开更多
This paper study stability of saturated salt solutions cells at 25 ℃. These cells were prepared and measured at National Institute for Standard （NIS-Egypt） to study the stability of the saturated salt solutions. Th...This paper study stability of saturated salt solutions cells at 25 ℃. These cells were prepared and measured at National Institute for Standard （NIS-Egypt） to study the stability of the saturated salt solutions. The study was carried out using three saturated salt solutions, which are Potassium Acetate 22.5%, Potassium Iodide 68.9% and Potassium Sulphate 97.3% to cover low, medium and high relative humidity. The study was carried out using different shapes and volumes half liter spherical, liter spherical and liter conical per each salt which was prepared. The apparatus which used in measurement system in the first time are the same which used after ten years. The results show that the change of relative humidity value after ten years ranged from 0.1% to 0.7%. This value is suitable within uncertainty ＋ 2%. The period of stability for each run for all cells was found to be more than five hours and this period enough for calibration. The measurements show that the cells are stable for more than ten years with accepted value.展开更多
We study symmetric hyperbolic systems with memory-type dissipation and investigate their dissipative structures.We treat two cases:memory-type diffusion and memory-type relaxation,and observe that the dissipative stru...We study symmetric hyperbolic systems with memory-type dissipation and investigate their dissipative structures.We treat two cases:memory-type diffusion and memory-type relaxation,and observe that the dissipative structures of these two cases are essentially different.Namely,we show that the dissipative structure of the system with memory-type diffusion is of the standard type,while that of the system with memory-type relaxation is of the regularity-loss type.展开更多
Complex networks are everywhere. A typical example is software network. How to measure and control coupling interactions of software components is a largely explored research problem in software network. In terms of g...Complex networks are everywhere. A typical example is software network. How to measure and control coupling interactions of software components is a largely explored research problem in software network. In terms of graph theory and linear algebra, this paper investigates a pair of coupling metrics to evaluate coupling interactions between the classes of object-oriented systems. These metrics differ from the majority of existing metrics in three aspects： Taking into account the strength that one class depends on other ones, reflecting indirect coupling, and distinguishing various coupling interaction. An empirical comparison of the novel measures with one of the most widely used coupling metrics is described. Specifically, an experiment about the relationships of this pair metrics is conducted. The result shows that software complexity derived from coupling interaction could not be accurately reflected by one dimension of coupling metric for negative correlation.展开更多
Beam model has been used widely in computer aided engineering for mechanical systems and the simulation results largely depend on the beam model, there are great demand for beam model with high accuracy and efficiency...Beam model has been used widely in computer aided engineering for mechanical systems and the simulation results largely depend on the beam model, there are great demand for beam model with high accuracy and efficiency in simulating the mechanical system with large deformation. In this work, a new model of Timoshenko beam for large deformations is proposed to improve the accuracy and efficiency. Absolute nodal coordinate formulation and geometrically-exact beam formulation, which make the model very suitable to simulate large deformation mechanical system, are first combined in the new beam model, the governing equations are then discrete by finite element methods and numerical difficulties are well solved by applying the shape function strategy. The new beam model is then applied to simulate the mechanical systems with large deformation and the simulations based on the traditional beam model and hexahedron element were also carried out to verify the results. The results show that good precision and efficiency in simulating the mechanical systems with large deformation can be obtained by the new Timoshenko beam model at the same time. The presented new method also serves as a good foundation for other simulation of mechanical systems.展开更多
文摘The definition and the criterion of a unified symmetry for a Hamilton system are presented. The sufficient condition under which the Noether symmetry is a unified symmetry for the system is given. A new conserved quantity,as well as the Noether conserved quantity and the Hojman conserved quantity, deduced from the unified symmetry, is obtained. An example is finally given to illustrate the application of the results.
基金The project supported by National Natural Science Foundation of China under Grant No. 10272021 and the Natural Science Foundation of High Education Department of Jiangsu Province under Grant No. 04KJA130135
文摘This paper focuses on studying the relation between a velocity-dependent symmetry and a generalized Lutzky conserved quantity for a holonomic system with remainder coordinates subjected to unilateral constraints. The differential equations of motion of the system are established, and the definition of Lie symmetry for the system is given. The conditions under which a Lie symmetry can directly lead up to a generalized Lutzky conserved quantity and the form of the new conserved quantity are obtained, and an example is given to illustrate the application of the results.
文摘This paper study stability of saturated salt solutions cells at 25 ℃. These cells were prepared and measured at National Institute for Standard （NIS-Egypt） to study the stability of the saturated salt solutions. The study was carried out using three saturated salt solutions, which are Potassium Acetate 22.5%, Potassium Iodide 68.9% and Potassium Sulphate 97.3% to cover low, medium and high relative humidity. The study was carried out using different shapes and volumes half liter spherical, liter spherical and liter conical per each salt which was prepared. The apparatus which used in measurement system in the first time are the same which used after ten years. The results show that the change of relative humidity value after ten years ranged from 0.1% to 0.7%. This value is suitable within uncertainty ＋ 2%. The period of stability for each run for all cells was found to be more than five hours and this period enough for calibration. The measurements show that the cells are stable for more than ten years with accepted value.
基金supported by Grant-in-Aid for Scientific Research (Grant No. 25220702)
文摘We study symmetric hyperbolic systems with memory-type dissipation and investigate their dissipative structures.We treat two cases:memory-type diffusion and memory-type relaxation,and observe that the dissipative structures of these two cases are essentially different.Namely,we show that the dissipative structure of the system with memory-type diffusion is of the standard type,while that of the system with memory-type relaxation is of the regularity-loss type.
基金This research is supported by the National Key Basic Research and Development 973 Program of China under Grant No. 2007CB310805, Foundation for the Author of National Excellent Doctoral Dissertation of China under Grant No. 2007B4, the National Natural Science Foundation of China under Grant Nos. 60873083, 60803025, and the National High Technology Research and Development Program of China under Grant No. 2006AA04Z156.
文摘Complex networks are everywhere. A typical example is software network. How to measure and control coupling interactions of software components is a largely explored research problem in software network. In terms of graph theory and linear algebra, this paper investigates a pair of coupling metrics to evaluate coupling interactions between the classes of object-oriented systems. These metrics differ from the majority of existing metrics in three aspects： Taking into account the strength that one class depends on other ones, reflecting indirect coupling, and distinguishing various coupling interaction. An empirical comparison of the novel measures with one of the most widely used coupling metrics is described. Specifically, an experiment about the relationships of this pair metrics is conducted. The result shows that software complexity derived from coupling interaction could not be accurately reflected by one dimension of coupling metric for negative correlation.
基金supported by the National Natural Science Foundation of China(Grant Nos.51605219&51375007)the Natural Science Foundation of Jiangsu Province(Grant Nos.BK20160791&SBK2015022352)+3 种基金the Visiting Scholar Foundation of the State Key Lab of Mechanical Transmission in Chongqing University(Grant Nos.SKLMT-KFKT-2014010&SKLMT-KFKT-201507)the start-up research foundation for new teachers in Nanjing University of Aeronautics and Astronautics(Grant No.1002-YAH16027)the Fundamental Research Funds for the Central Universities(Grant No.NE2016002)the Open Fund Program of the State Key Laboratory of Vehicle Lightweight Design,P.R.China(Grant No.20130303)
文摘Beam model has been used widely in computer aided engineering for mechanical systems and the simulation results largely depend on the beam model, there are great demand for beam model with high accuracy and efficiency in simulating the mechanical system with large deformation. In this work, a new model of Timoshenko beam for large deformations is proposed to improve the accuracy and efficiency. Absolute nodal coordinate formulation and geometrically-exact beam formulation, which make the model very suitable to simulate large deformation mechanical system, are first combined in the new beam model, the governing equations are then discrete by finite element methods and numerical difficulties are well solved by applying the shape function strategy. The new beam model is then applied to simulate the mechanical systems with large deformation and the simulations based on the traditional beam model and hexahedron element were also carried out to verify the results. The results show that good precision and efficiency in simulating the mechanical systems with large deformation can be obtained by the new Timoshenko beam model at the same time. The presented new method also serves as a good foundation for other simulation of mechanical systems.
