期刊文献+
共找到9篇文章
< 1 >
每页显示 20 50 100
Size dependent free vibration analysis of functionally graded piezoelectric micro/nano shell based on modified couple stress theory with considering thickness stretching effect 被引量:5
1
作者 Maryam Lori Dehsaraji Mohammad Arefi Abbas Loghman 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2021年第1期119-134,共16页
Higher-order shear and normal deformation theory is used in this paper to account thickness stretching effect for free vibration analysis of the cylindrical micro/nano shell subjected to an applied voltage and uniform... Higher-order shear and normal deformation theory is used in this paper to account thickness stretching effect for free vibration analysis of the cylindrical micro/nano shell subjected to an applied voltage and uniform temperature rising.Size dependency is included in governing equations based on the modified couple stress theory.Hamilton’s principle is used to derive governing equations of the cylindrical micro/nano shell.Solution procedure is developed using Navier technique for simply-supported boundary conditions.The numerical results are presented to investigate the effect of significant parameters such as some dimensionless geometric parameters,material properties,applied voltages and temperature rising on the free vibration responses. 展开更多
关键词 Thickness stretching effect Shear and normal deformation theory Vibration analysis Length scale parameter Modified couple stress theory
下载PDF
Discussion on the Hillert Theory of Normal Grain Growthwith a Modified Monte Carlo Simulation 被引量:1
2
作者 SONG Xiaoyan LIU Guoquan(Department of Materials Science and Engineering, USTB, Beijing 100083, China)(Department of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, PRC) 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 1997年第1期24-29,共6页
On the basis of analyzing some limitations in the existing algorithm, a modified Monte Carlo methodwas proposed to simulate two-dimensional normal grain growth. With the modified method. the simulated time exponent of... On the basis of analyzing some limitations in the existing algorithm, a modified Monte Carlo methodwas proposed to simulate two-dimensional normal grain growth. With the modified method. the simulated time exponent of grain growth attained n=0.49±0.01, which is very close to the theoretical value of the steady graingrowth n=0.5, indicating the possibility to investigate the total process of normal grain growth. The relationbetween the Hillert and the von Neumann equations were studied and identified, the Hillert's basic equation hasbeen found to hold during the normal grain growth. The grain size distribution was found to van continuouslyand slowly with the simulated time in the total growth process, the lognormal and the Hillert functions may betwo types of the expression forms during its transition, and the later seemingly corresponds at the distribution ofthe steady stage were n≈0.50. 展开更多
关键词 Monte Carlo simulation Hillert theory of normal grain growth von Neumann equation garin size distribution
下载PDF
DYNAMICAL BEHAVIOR OF AN INNOVATION DIFFUSION MODEL WITH INTRA-SPECIFIC COMPETITION BETWEEN COMPETING ADOPTERS 被引量:1
3
作者 Rakesh KUMAR Anuj Kumar SHARMA Govind Prasad SAHU 《Acta Mathematica Scientia》 SCIE CSCD 2022年第1期364-386,共23页
In this paper,we proposed an innovation diffusion model with three compartments to investigate the diffusion of an innovation(product)in a particular region.The model exhibits two equilibria,namely,the adopter-free an... In this paper,we proposed an innovation diffusion model with three compartments to investigate the diffusion of an innovation(product)in a particular region.The model exhibits two equilibria,namely,the adopter-free and an interior equilibrium.The existence and local stability of the adopter-free and interior equilibria are explored in terms of the effective Basic Influence Number(BIN)R_(A).It is investigated that the adopter free steady-state is stable if R_(A)<1.By consideringτ(the adoption experience of the adopters)as the bifurcation parameter,we have been able to obtain the critical value ofτresponsible for the periodic solutions due to Hopf bifurcation.The direction and stability analysis of bifurcating periodic solutions has been performed by using the arguments of normal form theory and the center manifold theorem.Exhaustive numerical simulations in the support of analytical results have been presented. 展开更多
关键词 intra-specific competition basic influence number local stability HOPF-BIFURCATION normal form theory center manifold theorem
下载PDF
A new perspective of ecosystem health 被引量:1
4
作者 LI Hai-tao GU Chen-jie +2 位作者 LIANG Tao JOHN Ranjeet XU Jian-ye 《Journal of Forestry Research》 SCIE CAS CSCD 2011年第1期127-132,共6页
Ecosystem health has attracted considerable attention from different disciplines in recent years. However, it still remains a disputed issue whether to focus on its general concept or on operational practice. As a res... Ecosystem health has attracted considerable attention from different disciplines in recent years. However, it still remains a disputed issue whether to focus on its general concept or on operational practice. As a result, these disputations have caused confusion and limited further research in the field of ecosystem health. In this paper, we attempt to introduce a new perspective to the concept of ecosystem health. With the aid of modern statistical methodology, such as factor analysis and normal distribution theory, we provide a conceptual approach to the quantitative assessment of ecosystem health and our method could be applied to various categories of ecosystems. 展开更多
关键词 ecosystem health MAJORITY factor analysis normal distribution theory
下载PDF
STABILITY AND BIFURCATION ANALYSIS OF A DELAYED INNOVATION DIFFUSION MODEL 被引量:1
5
作者 Rakesh KUMAR Anuj Kumar SHARMA Kulbhushan A GNIHOTRI 《Acta Mathematica Scientia》 SCIE CSCD 2018年第2期709-732,共24页
In this article, a nonlinear mathematical model for innovation diffusion with stage structure which incorporates the evaluation stage (time delay) is proposed. The model is analyzed by considering the effects of ext... In this article, a nonlinear mathematical model for innovation diffusion with stage structure which incorporates the evaluation stage (time delay) is proposed. The model is analyzed by considering the effects of external as well as internal influences and other demographic processes such as emigration, intrinsic growth rate, death rate, etc. The asymptotical stability of the various equilibria is investigated. By analyzing the exponential characteristic equation with delay-dependent coefficients obtained through the variational matrix, it is found that Hopf bifurcation occurs when the evaluation period (time delay, T) passes through a critical value. Applying the normal form theory and the center manifold argument, we de- rive the explicit formulas determining the properties of the bifurcating periodic solutions. To illustrate our theoretical analysis, some numerical simulations are also included. 展开更多
关键词 Innovation diffusion model stability analysis HOPF-BIFURCATION normal form theory center manifold theorem
下载PDF
The Novel Spectrum Allocation Algorithm in Cognitive Radio System 被引量:2
6
作者 Xiangqian Che Yupeng Xie +2 位作者 Ye Tian Qijing Zhang Guizhi Sun 《China Communications》 SCIE CSCD 2017年第3期108-117,共10页
In order to reduce the disturbance on an authorizing user and lower the competition between cognitive users, assure the normal communication of a cognitive radio system, reliability theory is applied to describe if a ... In order to reduce the disturbance on an authorizing user and lower the competition between cognitive users, assure the normal communication of a cognitive radio system, reliability theory is applied to describe if a channel can be used by a cognitive user or not and the probability that the channel is continually used for a period. Three aspects including space, time domain and frequency domain are united for the research on the distribution of frequency spectrum. The simulation result shows that, in the space domain, time domain, frequency domain algorithm, the transmitted data volume and the total throughput of the system are superior to those in greedy algorithm and time domain—frequency domain algorithm, the novel algorithm is helpful to reduce the disturbance caused by a cognitive user to an authorizing user and lower the competition between cognitive users, this simulation result shows that the proposed algorithm is effective. 展开更多
关键词 reliability theory spectrum allocation cognitive radio normal communication
下载PDF
GROWTH OF MEROMORPHIC SOLUTIONS OF SOME ALGEBRAIC DIFFERENTIAL EQUATIONS
7
作者 李叶舟 戚建明 袁文俊 《Acta Mathematica Scientia》 SCIE CSCD 2015年第1期105-111,共7页
In this paper, by means of the normal family theory, we estimate the growth order of meromorphic solutions of some algebraic differential equations and improve the related result of Barsegian et al. [6]. We also give ... In this paper, by means of the normal family theory, we estimate the growth order of meromorphic solutions of some algebraic differential equations and improve the related result of Barsegian et al. [6]. We also give some examples to show that our results occur in some special cases. 展开更多
关键词 the normal family theory algebraic differential equations meromorphic solutions GROWTH
下载PDF
The External Dimension of Europeanization and Social Conditionality: The Case of the Generalized System of Preferences
8
作者 Eleni Xiarchogiannopoulou 《International Relations and Diplomacy》 2014年第9期551-564,共14页
The aim of the paper is to clarify the mechanisms of external Europeanization. Studies so far claim that the more distant a country is from the EU core the more indirect the mechanisms of the external Europeanization ... The aim of the paper is to clarify the mechanisms of external Europeanization. Studies so far claim that the more distant a country is from the EU core the more indirect the mechanisms of the external Europeanization are. The paper problematizes this claim. Empirically it focuses on the case of social conditionality (SC) as applied in the area of social trade policy. Theoretically it follows Normal Accident Theory, as adapted in the area of the EU studies. The paper focuses on the interactions of the web of actors found in this policy area. It distinguishes between complex and tightly linked interactions. It hypothesizes that the less complex and the more tightly linked actors are the more direct the mechanisms of external Europeanization. SC is a "social" trade policy instrument that the EU includes to its trade agreements with developing countries through the Generalized System of Preferences (GSP) in order to promote the ratification and application of basic human rights, and labor, sustainable development and good governance standards. The GSP is a trade policy program that allows the exemption of developing countries from exports tariffs as a way of assisting their growth and development. SC is a "hard" instrument in the sense that it consists of both a positive aspect (carrots) and a negative one (sticks). Developing countries that ratify and apply basic human rights, and labor, sustainable development and good governance standards qualify for additional trade preferences (carrots), while failure of compliance results to the withdrawal of the preferences (sticks). 展开更多
关键词 mechanisms of external Europeanization social conditionality normal accident theory developing countries
下载PDF
Bifurcation behaviors analysis of a plankton model with multiple delays 被引量:2
9
作者 Anuj Kumar Sharma Amit Sharma Kulbhushan Agnihotri 《International Journal of Biomathematics》 2016年第6期113-137,共25页
A mathematical model describing the dynamics of toxin producing phytoplankton- zooplankton interaction with instantaneous nutrient recycling is proposed. We have explored the dynamics of plankton ecosystem with multip... A mathematical model describing the dynamics of toxin producing phytoplankton- zooplankton interaction with instantaneous nutrient recycling is proposed. We have explored the dynamics of plankton ecosystem with multiple delays; one due to gestation period in the growth of phytoplankton population and second due to the delay in toxin liberated by TPP. It is established that a sequence of Hopf bifurcations occurs at the interior equilibrium as the delay increases through its critical value. The direction of the Hopf bifurcation and the stability of the bifurcating periodic solutions are determined using the theory of normal form and center manifold. Meanwhile, effect of toxin on the stability of delayed plankton system is also established numerically. Finally, numerical simulations are carried out to support and supplement the analytical findings. 展开更多
关键词 PLANKTON multiple delays TOXIN Hopf bifurcation normal form theory centermanifold theorem.
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部