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Effects of heat treatment process on thin film alloy resistance and its stability 被引量:1
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作者 周继承 彭银桥 《Journal of Central South University of Technology》 2003年第2期91-93,共3页
Alloy thin film for advanced pressure sensors was manufactured by means of ion-beam sputtering SiO2 insulation film and NiCr thin film on the 17-4PH stainless steel elastic substrate. The thin film resistance was resp... Alloy thin film for advanced pressure sensors was manufactured by means of ion-beam sputtering SiO2 insulation film and NiCr thin film on the 17-4PH stainless steel elastic substrate. The thin film resistance was respectively heat-treated by four processes. The effects on stability of thin film alloy resistance were investigated, and paramaters of heat treatment that make thin film resistance stable were obtained. The experimental result indicates that the most stable thin film resistance can be obtained when it is heat-treated under protection of SiO2 and N2 at 673 K for 1 h, and then kept at 473 K for 24 h. Pressure sensor chips of high precision for harsh environments can be manufactured by this process. 展开更多
关键词 THIN film ALLOY RESISTANCE HEAT treatment STABILITY pressure sensors
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EXISTENCE AND NONEXISTENCE OF GLOBAL SOLUTIONS OF THE INITIAL-BOUNDARY VALUE PROBLEM FOR SOME DEGENERATE HYPERBOLIC EQUATION 被引量:1
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作者 叶耀军 《Acta Mathematica Scientia》 SCIE CSCD 2005年第4期703-709,共7页
The author considers the global existence and global nonexistence of the initial-boundary value problem for some degenerate hyperbolic equation of the form utt- div(|△↓|^P-2 △↓u)=|u|^m u, (x,t)∈[0, +∞)... The author considers the global existence and global nonexistence of the initial-boundary value problem for some degenerate hyperbolic equation of the form utt- div(|△↓|^P-2 △↓u)=|u|^m u, (x,t)∈[0, +∞) ×Ω with p 〉 2 and m 〉 0. He deals with the global solutions by D.H.Sattinger's potential well ideas. At the same time, when the initial energy is positive, but appropriately bounded, the global nonexistence of solutions is verified by using the analysis method. 展开更多
关键词 Degenerate hyperbolic equations global existence and global nonexistence initial-boundary value problem
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THE APPROXIMATION PROBLEM ON THE CLOSED CONVEX CONE AND ITS NUMERICAL SOLUTION
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作者 周富照 胡锡炎 张磊 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 2004年第1期64-71,共8页
In this paper, we study the approximation problem on the closed convex cone, and prove that there exists a unique solution of the approximation problem, then give the algorithm to compute the unique solution.
关键词 最优解 数值解 闭凸锥体 对称正交矩阵 HILBERT空间
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A new extension algorithm for cubic B-splines based on minimal strain energy 被引量:8
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作者 MO Guo-liang ZHAO Ya-nan 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第12期2043-2049,共7页
Extension of a B-spline curve or surface is a useful function in a CAD system. This paper presents an algorithm for extending cubic B-spline curves or surfaces to one or more target points. To keep the extension curve... Extension of a B-spline curve or surface is a useful function in a CAD system. This paper presents an algorithm for extending cubic B-spline curves or surfaces to one or more target points. To keep the extension curve segment GC^2-continuous with the original one, a family of cubic polynomial interpolation curves can be constructed. One curve is chosen as the solution from a sub-class of such a family by setting one GC^2 parameter to be zero and determining the second GC^2 parameter by minimizing the strain energy. To simplify the final curve representation, the extension segment is reparameterized to achieve C-continuity with the given B-spline curve, and then knot removal from the curve is done. As a result, a sub-optimized solution subject to the given constraints and criteria is obtained. Additionally, new control points of the extension B-spline segment can be determined by solving lower triangular linear equations. Some computing examples for comparing our method and other methods are given. 展开更多
关键词 GC^2-continuous EXTENSION Minimal strain energy Knot removal Reparametrization
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Reductions to Korteweg-de Vries Soliton Hierarchy 被引量:2
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作者 CHEN Jin-Bing TAN Rui-Mei GENG Xian-Guo 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第2期231-235,共5页
Based on the nonlinearization of Lax pairs, the Korteweg-de Vries (KdV) soliton hierarchy is decomposed into a family of finite-dimensional Hamiltonian systems, whose Liouville integrability is proved by means of th... Based on the nonlinearization of Lax pairs, the Korteweg-de Vries (KdV) soliton hierarchy is decomposed into a family of finite-dimensional Hamiltonian systems, whose Liouville integrability is proved by means of the elliptic coordinates. By applying the Abel-Jacobi coordinates on a Riemann surface of hyperelliptic curve, the resulting Hamiltonian flows as well as the KdV soliton hierarchy are ultimately reduced into linear superpositions, expressed by the Abel-Jacobi variables. 展开更多
关键词 KdV soliton hierarchy Hamiltonian systems Riemann surface Abel-Jacobi coordinates
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INFINITELY MANY SOLUTIONS FOR ELLIPTIC SYSTEMS WITH STRONGLY INDEFINITE VARIATIONAL STRUCTURE 被引量:1
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作者 刘朝霞 《Acta Mathematica Scientia》 SCIE CSCD 2010年第1期55-64,共10页
Based on the multiplicity results of Benci and Fortunato [4], we consider some elliptic systems with strongly indefinite quadratic part, and establish the existence of infinitely many nontrivial solutions in a suitabl... Based on the multiplicity results of Benci and Fortunato [4], we consider some elliptic systems with strongly indefinite quadratic part, and establish the existence of infinitely many nontrivial solutions in a suitable family of products of fractional Sobolev spaces. 展开更多
关键词 semilinear elliptic systems variational functional (P.S.)c sequence criticalpoint
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ON A CLASS OF INHOMOGENEOUS,ENERGY-CRITICAL,FOCUSING,NONLINEAR SCHRDINGER EQUATIONS 被引量:1
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作者 刘朝霞 《Acta Mathematica Scientia》 SCIE CSCD 2013年第6期1522-1530,共9页
In this paper, we study the Cauchy problem of the inhomogeneous energy-critical Schrōdinger equation: iаtu=-△u-k(x)|u|4/N-2u,N≥3. Using the potential well method, we establish some new sharp criteria for blow... In this paper, we study the Cauchy problem of the inhomogeneous energy-critical Schrōdinger equation: iаtu=-△u-k(x)|u|4/N-2u,N≥3. Using the potential well method, we establish some new sharp criteria for blow-up of solutions in tile nonradial case. In particular, our conclusion in some sense improves on the results in [Kenig and Merle, invent. Math. 166, 645-675 (2006)], where only the radial case is considered in dimensions 3. 4. 5. 展开更多
关键词 focusing Schrōdinger equation critical energy
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Designing Bézier surfaces minimizing the L^2-norm of the Gaussian curvature
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作者 MO Guo-liang WU Ming-hua 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第1期142-148,共7页
In freeform surface modelling, developable surfaces have much application value. But, in 3D space, there is not always a regular developable surface which interpolates the given boundary of an arbitrary piecewise smoo... In freeform surface modelling, developable surfaces have much application value. But, in 3D space, there is not always a regular developable surface which interpolates the given boundary of an arbitrary piecewise smooth closed curve. In this paper, tensor product Bézier surfaces interpolating the closed curves are determined and the resulting surface is a minimum of the functional defined by the L2-integral norm of the Gaussian curvature. The Gaussian curvature of the surfaces is minimized by the method of solving nonlinear optimization problems. An improved approach trust-region form method is proposed. A simple application example is also given. 展开更多
关键词 ensor product polynomial surfaces Gaussian curvature L^2-integral norm Texture mapping Nonlinear optimization
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Asymptotic Behavior of Global Solutions for Double Degenerate Nonlinear Parabolic Equation
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作者 叶耀军 刘秋香 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2005年第4期390-394,共5页
In this paper we study the decay estimate of global solutions to the initial-boundary value problem for double degenerate nonlinear parabolic equation by using a dif-ference inequality.
关键词 double degenerate parabolic equations initial-boundary value problem global solutions asymptotic property
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Invariant subspaces and conditional Lie-Bcklund symmetries of inhomogeneous nonlinear difusion equations 被引量:10
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作者 QU ChangZheng JI LiNa 《Science China Mathematics》 SCIE 2013年第11期2187-2203,共17页
The inhomogeneous nonlinear diffusion equation is studied by invariant subspace and condi- tional Lie=Bgcklund symmetry methods. It is shown that the equations admit a class of invariant subspaces governed by the nonl... The inhomogeneous nonlinear diffusion equation is studied by invariant subspace and condi- tional Lie=Bgcklund symmetry methods. It is shown that the equations admit a class of invariant subspaces governed by the nonlinear ordinary differential equations, which is equivalent to a kind of higher=order conditional Lie-B^icklund symmetries of the equations. As a consequence, a number of new solutions to the inhomogeneous nonlinear diffusion equations are constructed explicitly or reduced to solving finite-dimensional dynamical sys- tems. 展开更多
关键词 inhomogeneous nonlinear diffusion equation invariant subspace conditional Lie-B/icklund sym-metry functionally generalized separable solution
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A SINGULAR BIOECONOMIC MODEL WITH DIFFUSION AND TIME DELAY
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作者 Qingling ZHANG Xue ZHANG Chao LIU 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2011年第2期277-290,共14页
This paper studies a prey-predator singular bioeconomic system with time delay and diffusion, which is described by differential-algebraic equations. For this system without diffusion, there exist three bifurcation ph... This paper studies a prey-predator singular bioeconomic system with time delay and diffusion, which is described by differential-algebraic equations. For this system without diffusion, there exist three bifurcation phenomena: Transcritical bifurcation, singularity induced bifurcation, and Hopf bifurcation. Compared with other biological systems described by differential equations, singularity induced bifurcation only occurs in singular system and usually links with the expansion of population. When the diffusion is present, it is shown that the positive equilibrium point loses its stability at some critical values of diffusion rate and periodic oscillations occur due to the increase of time delay. Furthermore, numerical simulations illustrate the effectiveness of results and the related biological implications are discussed. 展开更多
关键词 DIFFUSION hopf bifurcation singular bioeconomic model singularity induced bifurcation time delay transcritical bifurcation.
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Visualisation techniques to support public interpretation of future climate change and land-use choices:a case study from N-E Scotland
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作者 Chen Wang David Miller +2 位作者 Iain Brown Yang Jiang Marie Castellazzi 《International Journal of Digital Earth》 SCIE EI CSCD 2016年第6期586-605,共20页
Mitigating and adapting to climate change includes a requirement to evaluate the role of future land uses in delivering robust integrated responses that are sensitive to local landscape contexts.In practice,this empha... Mitigating and adapting to climate change includes a requirement to evaluate the role of future land uses in delivering robust integrated responses that are sensitive to local landscape contexts.In practice,this emphasises the need for community engagement,planning and inclusive decision-making.Community engagement may be potentially facilitated by the use of spatially explicit quantitative scenarios of landuse change in combination with interactive visualisation.This requires a coherent framework to integrate spatial data modelling,analytical capabilities and visualisation tools in a format that will also engage diverse public audiences.These challenges were explored with a case study of virtual landscapes from N-E Scotland that was used to test preferences for scenarios of future land use.Visualisations employed texture-based rendering rather than full photo-realistic rendering to facilitate interactivity and this provided additional scope for audiences to explore multiple future scenarios compared to the present landscape.Interactive voting in a virtual landscape theatre suggested preferences for visual diversity,good stewardship and perceived naturalness that should be considered in developing planned responses to change.Further investigation of preferences was conducted using interactive 3D features located within the landscape.Study findings are reviewed against objectives for inclusive engagement in the Digital Earth agenda and used to make further recommendations on the use of scenarios and visualisation tools.In particular,technical advances in user engagement need to be developed in conjunction with emerging good practice that addresses ethical,behavioural and inclusion issues so that the content is presented in as transparent and unbiased format as possible. 展开更多
关键词 Landscape visualisation geographic information systems land-use scenarios public participation knowledge exchange
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Estimates for the Tail Probability of the Supremum of a Random Walk with Independent Increments
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作者 Yang YANG Kaiyong WANG 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2011年第6期847-856,共10页
The authors investigate the tail probability of the supremum of a random walk with independent increments and obtain some equivalent assertions in the case that the increments are independent and identically distribut... The authors investigate the tail probability of the supremum of a random walk with independent increments and obtain some equivalent assertions in the case that the increments are independent and identically distributed random variables with Osubexponential integrated distributions.A uniform upper bound is derived for the distribution of the supremum of a random walk with independent but non-identically distributed increments,whose tail distributions are dominated by a common tail distribution with an O-subexponential integrated distribution. 展开更多
关键词 Random walk O-Subexponential distribution Integrated distribution SUPREMUM
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Maximal Dimension of Invariant Subspaces to Systems of Nonlinear Evolution Equations 被引量:13
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作者 Shoufeng SHEN Changzheng QU +1 位作者 Yongyang JIN Lina JI 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2012年第2期161-178,共18页
In this paper, the dimension of invariant subspaces admitted by nonlinear sys- tems is estimated under certain conditions. It is shown that if the two-component nonlinear vector differential operator F = (F1, F2) wi... In this paper, the dimension of invariant subspaces admitted by nonlinear sys- tems is estimated under certain conditions. It is shown that if the two-component nonlinear vector differential operator F = (F1, F2) with orders {k1, k2} (k1≥ k2) preserves the invariant subspace Wn1^1× Wn2^2 (n1 ≥ n2), then n1 - n2 ≤ k2, n1 ≤2(k1 + k2) + 1, where Wnq^q is the space generated by solutions of a linear ordinary differential equation of order nq (q = 1, 2). Several examples including the (1+1)-dimensional diffusion system and Ito's type, Drinfel'd-Sokolov-Wilson's type and Whitham-Broer-Kaup's type equations are presented to illustrate the result. Furthermore, the estimate of dimension for m-component nonlinear systems is also given. 展开更多
关键词 Invariant subspace Nonlinear PDEs Exact solution SYMMETRY Dynamical system
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Long Time L^1-behavior for the Incompressible Magneto-hydrodynamic Equations in a Half-space
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作者 Zhao-xia LIU Xing-jiang YU 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2016年第4期933-944,共12页
The large time Ll-behavior of the strong solution (including the first and second order spacial derivatives) to the incompressible magneto-hydrodynamic (MHD) equations is given in a half-space. The main tool emplo... The large time Ll-behavior of the strong solution (including the first and second order spacial derivatives) to the incompressible magneto-hydrodynamic (MHD) equations is given in a half-space. The main tool employed in this article is a new weighted estimate for the Stokes flow in L1(Rn+), such a study is of independent interest. 展开更多
关键词 MHD equation strong solution asymptotic behavior HALF-SPACE
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Existence of Solutions for the Critical Elliptic System with Inverse Square Potentials
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作者 Zhao-xia LIU Zhao-hui LIU 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2013年第2期315-328,共14页
Let Ω∈← 0 be an open bounded domain in RN (N 〉 3) and 2*(s) = 2(N-8) =2(N-s)N-22. We consider the following elliptic system of two equations in where A, μ 〉 0 and α, β 〉 1 satisfy α + β = 2*(s... Let Ω∈← 0 be an open bounded domain in RN (N 〉 3) and 2*(s) = 2(N-8) =2(N-s)N-22. We consider the following elliptic system of two equations in where A, μ 〉 0 and α, β 〉 1 satisfy α + β = 2*(s). Using the Moser iteration, we prove the asymptotic behavior of solutions at the origin. In addition, by exploiting the Mountain-Pass theorem, we establish the existence of solutions. 展开更多
关键词 elliptic system variational functional Palais-Smale condition critical point
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