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ASYMPTOTIC BEHAVIOR OF SOLUTIONS OF SECOND ORDER NONLINEAR ELLIPTIC DIFFERENTIAL EQUATIONS 被引量:3
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作者 徐志庭 《Acta Mathematica Scientia》 SCIE CSCD 2001年第1期131-136,共6页
In this paper, the second order nonlinear elliptic differential equations (E) (n)Sigma (i,j=1) partial derivative/partial derivativex(j)[a(i,j)(x,y) partial derivative/partial derivativex(j)y] + q(x)f(y) = e(x) are co... In this paper, the second order nonlinear elliptic differential equations (E) (n)Sigma (i,j=1) partial derivative/partial derivativex(j)[a(i,j)(x,y) partial derivative/partial derivativex(j)y] + q(x)f(y) = e(x) are considered in an exterior Omega subset of R-n, where q(x) is allowed to change sign. Some sufficient conditions for any solutions y(x) of (E) to be satisfied liminf\\x\--> infinity \y(x)\ = 0 are obtained. Particularly, these results improve the previous results for second order ordinary differential equations. 展开更多
关键词 nonlinear elliptic differential equations weakly integrally small coefficient factor
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Experimental Investigation and Prediction Model of the Loads Exerted by Oblique Internal Solitary Waves on FPSO 被引量:5
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作者 ZHANG Rui-rui WANG Hong-wei +3 位作者 CHEN Ke YOU Yun-xiang ZHANG Shu-guang XIONG Xiao-hu 《China Ocean Engineering》 SCIE EI CSCD 2022年第2期179-190,共12页
By using a 30-meter-long wave flume equipped with a double-plate wave maker,a series of depression ISWs were generated in a density stratified two-layer fluid and the forces exerted by oblique internal solitary waves(... By using a 30-meter-long wave flume equipped with a double-plate wave maker,a series of depression ISWs were generated in a density stratified two-layer fluid and the forces exerted by oblique internal solitary waves(ISWs)on fixed FPSO model had been measured.According to the laboratory experiments,a numerical flume taken the applicability of KdV,eKdV and MCC ISWs theories in consideration was adopted to study the force components.Based on the experimental data and the force composition,the simplified prediction model was established.It was shown that the horizontal and transversal loads consisted of two parts:the Froude−Krylov force that could be calculated by integrating the dynamic pressure induced by ISW along the FPSO wetted surface,as well as the viscous force that could be obtained by multiplying the friction coefficient Cfx(C_(fy)),correction factor K_(x)(K_(y))and the integration of particle tangential velocity along the FPSO wetted surface.The vertical load was mainly the vertical Froude−Krylov force.Based on the experimental results,a conclusion can be drawn that the friction coefficient Cf and correction factor K were regressed as a relationship of Reynolds number Re,Keulegan-Carpenter number KC,upper layer depth h1/h and ISW accident angleα.Moreover,the horizontal friction coefficient Cfx yielded the logarithmic function with Re,and transversal friction coefficient C_(fy)obeyed the exponent function with Re,while the correction factors K_(x)and K_(y)followed power function with KC.The force prediction was also performed based on the regression formulae and pressure integral.The predicted results agreed well with the experimental results.The maximum forces increase linearly with the ISWs amplitude.Besides,the upper layer thickness had an obvious influence on the extreme value of the horizontal and transversal forces. 展开更多
关键词 internal solitary wave(ISW) FPSO wave forces friction coefficient and correction factor accident angle
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Steady rotation of a composite sphere in a concentric spherical cavity 被引量:1
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作者 D.Srinivasacharya M.Krishna Prasad 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2012年第3期653-658,共6页
The problem of steady rotation of a composite sphere located at the centre of a spherical container has been investigated. A composite particle referred to in this paper is a spherical solid core covered with a permea... The problem of steady rotation of a composite sphere located at the centre of a spherical container has been investigated. A composite particle referred to in this paper is a spherical solid core covered with a permeable spherical shell. The Brinkman's model for the flow inside the compos- ite sphere and the Stokes equation for the flow in the spheri- cal container were used to study the motion. The torque ex- perienced by the porous spherical particle in the presence of cavity is obtained. The wall correction factor is calculated. In the limiting cases, the analytical solution describing the torque for a porous sphere and for a solid sphere in an un- bounded medium are obtained from the present analysis. 展开更多
关键词 Rotation Porous sphere Solid core Stokesflow Brinkman equation Stress jump coefficient. Torque Wall correction factor
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Principal Component-Discrimination Model and Its Application
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作者 韩天锡 魏雪丽 +1 位作者 蒋淳 张玉琍 《Transactions of Tianjin University》 EI CAS 2004年第4期315-318,共4页
Having researched for many years, seismologists in China presented about 80 earthquake prediction factors which reflected omen information of earthquake. How to concentrate the information that the 80 earthquake predi... Having researched for many years, seismologists in China presented about 80 earthquake prediction factors which reflected omen information of earthquake. How to concentrate the information that the 80 earthquake prediction factors have and how to choose the main factors to predict earthquakes precisely have become one of the topics in seismology. The model of principal component-discrimination consists of principal component analysis, correlation analysis, weighted method of principal factor coefficients and Mahalanobis distance discrimination analysis. This model combines the method of maximization earthquake prediction factor information with the weighted method of principal factor coefficients and correlation analysis to choose earthquake prediction variables, applying Mahalanobis distance discrimination to establishing earthquake prediction discrimination model. This model was applied to analyzing the earthquake data of Northern China area and obtained good prediction results. 展开更多
关键词 principal component analysis discrimination analysis correlation analysis weighted method of principal factor coefficients
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On Invertibility of Some Functional Operators with Shift
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作者 Aleksandr Karelin Anna Tarasenko Manuel Gonzalez-Hernandez 《Applied Mathematics》 2022年第8期651-657,共7页
In this paper, we consider operators arising in the modeling of renewable systems with elements that can be in different states. These operators are functional operators with non-Carlemann shifts and they act in Holde... In this paper, we consider operators arising in the modeling of renewable systems with elements that can be in different states. These operators are functional operators with non-Carlemann shifts and they act in Holder spaces with weight. The main attention was paid to non-linear equations relating coefficients to operators with a shift. The solutions of these equations were used to reduce the operators under consideration to operators with shift, the invertibility conditions for which were found in previous articles of the authors. To construct the solution of the non-linear equation, we consider the coefficient factorization problem (the homogeneous equation with a zero right-hand side) and the jump problem (the non-homogeneous equation with a unit coefficient). The solution of the general equation is represented as a composition of the solutions to these two problems. 展开更多
关键词 Operator with a Non-Carlemann Shift Inverse Operator Non-Linear Equation Factorization of coefficient Equation with Unit coefficient
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Analysis of the influencing factors of PAEs volatilization from typical plastic products 被引量:5
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作者 Weidong Chen Chenchen Chi +3 位作者 Chen Zhou Meng Xia Cees Ronda Xueyou Shen 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2018年第4期61-70,共10页
The primary emphasis of this research was to investigate the foundations of phthalate(PAEs) pollutant source researches and then firstly confirmed the concept of the coefficient of volatile strength, namely phthalat... The primary emphasis of this research was to investigate the foundations of phthalate(PAEs) pollutant source researches and then firstly confirmed the concept of the coefficient of volatile strength, namely phthalate total content in per unit mass and unit surface area of pollutant sources. Through surveying and evaluating the coefficient of volatile strength of PAEs from typical plastic products, this research carried out reasonable classification of PAEs pollutant sources into three categories and then investigated the relationship amongst the coefficient of volatile strength as well as other environmental factors and the concentration level of total PAEs in indoor air measured in environment chambers.Research obtained phthalate concentration results under different temperature, humidity,the coefficient of volatile strength and the closed time through the chamber experiment. In addition, this study further explored the correlation and ratio of influencing factors that affect the concentration level of total PAEs in environment chambers, including environmental factors, the coefficient of volatile strengths of PAEs and contents of total PAEs in plastic products. The research created an improved database system of phthalate the coefficient of volatile strengths of each type of plastic goods, and tentatively revealed that the volatile patterns of PAEs from different typical plastic goods, finally confirmed that the coefficient of volatile strengths of PAEs is a major factor that affects the indoor air total PAEs concentration, which laid a solid foundation for further establishing the volatile equation of PAEs from plastic products. 展开更多
关键词 Phthalate esters Air The coefficient of volatile strength Typical plastic products The influencing factors
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The Input-Output Model and the Analysis of Profit and Tax of Product
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作者 YANG Hongzhi Xinyang Teacher’s College,Xinyang 464000 《Systems Science and Systems Engineering》 CSCD 1994年第3期263-268,共6页
With the combination of modern quantitative analysis method and enterprise inputoutput model,in this paper we make a scientific analysis on the effect to product profit tax from the change of internal and external imp... With the combination of modern quantitative analysis method and enterprise inputoutput model,in this paper we make a scientific analysis on the effect to product profit tax from the change of internal and external important factors of enterprise,and some important results hare been given. 展开更多
关键词 input-output model coefficient matrix constructed by factors on cost total absorption coefficient matrix boundary cost coefficient matrix flexible coefficient matrix
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