杂交晚稻旱育移栽秧龄弹性界限及其产量效应试验

通过对中熟杂交组合Ⅱ优９２不同秧龄期的试验，研究了其移栽秧龄弹性界限及产量效应。结果表明，连作杂交晚稻Ⅱ优９２组合在同期播种、旱育移栽条件下，不同秧龄期移栽与产量呈极显著负相关，２５～３０ｄ秧龄为最适秧龄期，４０～４５ｄ处理比２５～３５ｄ的极显著减产。从而明确了其秧龄弹性的界限在３５～４０ｄ之间。秧龄延长减产的原因是移栽后营养生长期增长和生殖生长期缩短，导致穗型变小。

基于自然交互的FBS设计模型

目的研究FBS设计模型的需求模糊问题,得出因地制宜、因时制宜、因人制宜的表达(即功能实现),从而得到"用户需求"的最优解。方法针对"模糊需求"问题,提出了"弹性界限"的概念,以自然交互的方法,通过对产品使用情境的上下文进行分析,对产品的情境感知进行预设,对"模糊需求"进行设计视域下的求解。结论在设计研发早期,可以将弹性界限形成的域值看作设计范畴,融入到设计中去。

Scattering of Surface Water Waves Involving Semi-infinite Floating Elastic Plates on Water of Finite Depth

Two problems of scattering of surface water waves involving a semi-infinite elastic plate and a pair of semi-infinite elastic plates,separated by a gap of finite width,floating horizontally on water of finite depth,are investigated in the present work for a two-dimensional time-harmonic case.Within the frame of linear water wave theory,the solutions of the two boundary value problems under consideration have been represented in the forms of eigenfunction expansions.Approximate values of the reflection and transmission coefficients are obtained by solving an over-determined system of linear algebraic equations in each problem.In both the problems,the method of least squares as well as the singular value decomposition have been employed and tables of numerical values of the reflection and transmission coefficients are presented for specific choices of the parameters for modelling the elastic plates.Our main aim is to check the energy balance relation in each problem which plays a very important role in the present approach of solutions of mixed boundary value problems involving Laplace equations.The main advantage of the present approach of solutions is that the results for the values of reflection and transmission coefficients obtained by using both the methods are found to satisfy the energy-balance relations associated with the respective scattering problems under consideration.The absolute values of the reflection and transmission coefficients are presented graphically against different values of the wave numbers.

Scaled boundary isogeometric analysis for 2D elastostatics

A new numerical method,scaled boundary isogeometric analysis(SBIGA)combining the concept of the scaled boundary finite element method(SBFEM)and the isogeometric analysis(IGA),is proposed in this study for 2D elastostatic problems with both homogenous and inhomogeneous essential boundary conditions.Scaled boundary isogeometric transformation is established at a specified scaling center with boundary isogeometric representation identical to the design model imported from CAD system,which can be automatically refined without communication with the original system and keeping geometry invariability.The field variable,that is,displacement,is constructed by the same basis as boundary isogeometric description keeping analytical features in radial direction.A Lagrange multiplier scheme is suggested to impose the inhomogeneous essential boundary conditions.The new proposed method holds the semi-analytical feature inherited from SBFEM,that is,discretization only on boundaries rather than the entire domain,and isogeometric boundary geometry from IGA,which further increases the accuracy of the solution.Numerical examples,including circular cavity in full plane,Timoshenko beam with inhomogenous boundary conditions and infinite plate with circular hole subjected to remotely tension,demonstrate that SBIGA can be applied efficiently to elastostatic problems with various boundary conditions,and powerful in accuracy of solution and less degrees of freedom(DOF)can be achieved in SBIGA than other methods.

HIGH ACCURACY ANALYSIS OF THE FINITE ELEMENT METHOD FOR NONLINEAR VISCOELASTIC WAVE EQUATIONS WITH NONLINEAR BOUNDARY CONDITIONS

The standard finite elements of degree p over the rectangular meshes are applied to solve a kind of nonlinear viscoelastic wave equations with nonlinear boundary conditions, and the superclose property of the continuous Galerkin approximation is derived without using the nonclassical elliptic projection of the exact solution of the model problem. The global superconvergence of one order higher than the traditional error estimate is also obtained through the postprocessing technique.

Residual-based a posteriori error estimates for symmetric conforming mixed finite elements for linear elasticity problems

A posteriori error estimators for the symmetric mixed finite element methods for linear elasticity problems with Dirichlet and mixed boundary conditions are proposed. Reliability and efficiency of the estimators are proved. Numerical examples are presented to verify the theoretical results.