基于Moldflow的多样条注塑模流道优化设计

多样条注塑模具是进行试样力学性能测试的关键。文中设计了2型腔非平衡式拉伸、冲击样条注射模流道结构,运用Moldflow软件模拟熔料的填充和流动平衡分析,获得最佳的流道设计,并应用于模具设计中。

基于多节点样条理论的漏磁数据去冗余压缩算法

为解决管道漏磁缺陷检测中采样数据的去冗余压缩问题,在利用小波去噪的基础上,根据多节点样条理论具有插值过程无需解方程组、逼近误差小、基函数有界支集的性质,通过构造一个对称的、局部支集的、拉格朗日型基函数,从而设计出一种能快速、高效地逼近原检测数据的去冗余压缩新算法,以提高管道漏磁在线检测数据压缩的实时性.用实验室检测到的漏磁数据对该算法进行了验证.结果表明,该算法具有很好的实时性及较高的数据压缩率.

考虑地震波随机性及水位影响的高土石坝易损性研究

考虑地震动输入数量及不同水位工况下的流固耦合影响,采用弹塑性模型非线性有限元方法对国内某高土石坝进行动力分析,再通过多样条分析(MSA)法对该坝地震易损性研究。根据场地条件选取40条地震波,并对高土石坝震害等级进行划分,选取坝体相对震陷率作为易损性极限状态指标;采用动力固结有限元程序SWANDYNE II对大坝进行动力计算,再采用MSA法得到地震易损性曲线。通过不同地震波数量的易损性方程参数分析,确定地震波合适的输入数量。通过对不同水位和地震动强度作用下的高土石坝三维易损性曲线发现,在相同地震作用下,随着水位的升高,大坝不同等级相应的破坏概率增大。综合考虑不同水位和地震动输入数量对高土石坝地震易损性的影响,可为高土石坝抗震安全评估提供参考依据。

±800kV换流变压器地震易损性分析

换流变压器是特高压换流站中的关键设备,为了评估其抗震性能及地震易损性,对某±800 kV换流变压器建立精细化有限元模型,通过时程响应分析研究其地震作用下响应特征和潜在失效模式;利用多样条易损性分析方法得到其地震易损性曲线,并研究了在阀侧套管升高座顶部设置落地支架以提高其抗震性能的可行性。结果表明:换流变压器的阀侧套管基频低于1 Hz,在地震作用下易产生过大的顶部位移响应;而从根部应力角度而言,网侧套管相较阀侧套管地震易损性更高。研究结果表明,换流变压器套管变形失效模式的发生概率高于其强度失效模式。在阀侧升高座端部设置落地支架,可以降低阀侧套管升高座顶部的加速度响应;考虑变形、强度双重失效模式下,增设支架可以有效降低换流变压器的地震易损性。

Real option pricing method for R&D investment under changing risk-free rate and discount rate

The polynomial spline model, which belongs to the static term structure model of interest rates, is studied. Every cash flow of the project is discounted relatively accurately by obtaining the discount rate from the static term structure model of interest rates. A simple basic model, which belongs to the dynamic term structure model, is studied, and the option pricing formula under changing risk-free rates is obtained by bringing it into the option pricing formula. Both dynamic and static term structure models are estimated by the use of the data of buy-back rates and the Shanghai Stock Exchange, and an example is given to compare the differences between the traditional method and the method under the changes in the interest rates and the discount rates.

Multi-modality liver image registration based on multilevel B-splines free-form deformation and L-BFGS optimal algorithm

A new coarse-to-fine strategy was proposed for nonrigid registration of computed tomography(CT) and magnetic resonance(MR) images of a liver.This hierarchical framework consisted of an affine transformation and a B-splines free-form deformation(FFD).The affine transformation performed a rough registration targeting the mismatch between the CT and MR images.The B-splines FFD transformation performed a finer registration by correcting local motion deformation.In the registration algorithm,the normalized mutual information(NMI) was used as similarity measure,and the limited memory Broyden-Fletcher- Goldfarb-Shannon(L-BFGS) optimization method was applied for optimization process.The algorithm was applied to the fully automated registration of liver CT and MR images in three subjects.The results demonstrate that the proposed method not only significantly improves the registration accuracy but also reduces the running time,which is effective and efficient for nonrigid registration.

Diatom diet selectivity by early post-larval abalone Haliotis diversicolor supertexta under hatchery conditions

Benthic diatoms constitute the primary diet of abalone during their early stages of development. To evaluate the dietary preferences of early post-larval abalone, Haliotis diversicolor supertexta, we analyzed the gut contents of post-larvae that settled on diatom films. We compared the abundance and species diversity of diatom assemblages in the gut to those of the epiphytic diatom assemblages on the attachment films, and identified 40 benthic diatom species in the gut contents of post-larvae 12 to 24 d after settlement. The most abtmdant taxa in the gut contents were Navicula spp., Amphora copulate, and Amphora coffeaeformis. Navicula spp. accounted for 64.0% of the cell density. In the attachment films, we identified 110 diatom species belonging to 38 genera. Pennate diatoms were the dominant members including the species Amphiprora alata, Cocconeis placentula var. euglypta, Cylindrotheca closterium, Navicula sp. 2, and A. coffeaeformis. Nano-diatoms （〈20 pm in length） accounted for a considerable proportion of the total species number and cell density of the diatom assemblages in the gut contents and on the films. This suggests that nano-diatoms are important to the efficient production of abalone seed. The difference of the composition and abundance of diatoms between in the guts and on the biofilms suggests that early post-larval grazing was selective. An early post-larval abalone preferred nano-diatoms and the genera Navicula and Amphora during the month after settlement.

Effect of Crystallization Conditions on Polymorphic Diversity of Malic Acid RS-Racemate

Enantiomers （R （＋） and S（-））, RS-racemate mixture of enantiomers） of malic acid C4H605 have been （double compound） and （R ＋ S） -conglomerate （mechanical investigated by means of X-ray diffractometry and high tern- perature X-ray diffraction method. The RS-racemate was found to be able to form three polymorphic modifications, which we denominated as M1 （monoclinic, space group P21/c）, M2 （monoclinic, space group Cc）, and Tc （triclinic, space group P-l ）, the latter modification having been unknown before. Modification Tc was also described, and its X- ray diffraction characteristics, including interplanar spacings d, hkl indices, unit cell parameters, were defined. In addi- tion, X-ray diffraction characteristics for both reported earlier M1 and M2 monoclinic polymorphic modifications were measured with higher accuracy. The ability of RS-racemate to form one of the above three modifications （MI, M2, and Tc） or their mixtures containing various proportions and combinations of the components （M1 ＋ M2, M1 ＋ Tc, or M2 ＋ Tc） was found to depend on the type of crystallization medium （a melt, aqueous medium, ethanol or acetone solu- tion）, crystallization rate （from 2--3 minutes to 4 months）, and crystallization temperature. Heating S-enantiomer and M1 RS-racemate up to their respective melting points （100 ℃ and 124 ℃, correspondingly） only made them undergo thermal deformations, while heating （R ＋ S） -conglomerate in the temperature range of 96--110 ℃ resulted in its homogenization to form M2 RS-racemate, which, near the melting point （118 ℃）, namely, in the range of 112-116 ℃, was transformed into MI RS-racemate. Keywords： polvmorDhism; racemic, chiral

Interpolation in R^2 with Minimum Value of the Uniform Norm of the Laplace Operator

Problems, which are studied in the paper, concern to theoretical aspects of interpolation theory. As is known, interpolation is one of the methods for approximate representation or recovery of functions on the basis of their given values at points of a grid. Interpolating functions can be chosen by many various ways. In the paper the authors are interested in interpolating functions, for which the Laplace operator, applied to them, has a minimal norm. The authors interpolate infinite bounded sequences at the knots of the square grid in Euclidian space. The considered problem is formulated as an extremal one. The main result of the paper is the theorem, in which certain estimates for the uniform norm of the Laplace operator applied to smooth interpolating functions of two real variables are established for the class of all bounded （in the corresponding discrete norm） interpolated sequences. Also connections of the considered interpolation problem with other problems and with embeddings of the Sobolev classes into the space of continuous functions are discussed. In the final part of the main section of the paper, the authors formulate some open problems in this area and sketch possible approaches to the search of solutions. In order to prove the main results, the authors use methods of classical mathematical analysis and the theory of polynomial splines of one variable with equidistant knots.

生物多样性条约第七次缔约国会议

生物多样性条约第七次缔约国会议于2004年2月9～20日在马来西亚吉隆坡召开，与会的180个国家的政府就濒临灭绝的种的保护及原住民的权利保障的行动计划框架达成了一致意见。

Bivariate Simplex Spline Quasi-Interpolants

In this paper we use the simplex B-spline representation of polynomials or piecewise polynomials in terms of their polar forms to construct several differential or discrete bivariate quasi interpolants which have an optimal approximation order.This method provides an efficient tool for describing many approximation schemes involving values and(or) derivatives of a given function.

A polynomial smooth epsilon-support vector regression based on cubic spline interpolation

Regression analysis is often formulated as an optimization problem with squared loss functions. Facing the challenge of the selection of the proper function class with polynomial smooth techniques applied to support vector regression models, this study takes cubic spline interpolation to generate a new polynomial smooth function ｜×｜ε^ 2, in g-insensitive support vector regression. Theoretical analysis shows that Sε^2 -function is better than pε^2 -function in properties, and the approximation accuracy of the proposed smoothing function is two order higher than that of classical pε^2 -function. The experimental data shows the efficiency of the new approach.

Thin-Plate Spline Analysis of Diversity in Field Populations of Codling Moth, Cydia pomonella L. （Lep., Tortricidae） in North West of Iran

In order to study morphological diversity of codling moth, Cydia pomonella （L.） using thin-plate spline analysis, nine geographical populations from four north western provinces of Iran namely East Azarbayjan, West Azarbayjan, Ardebil and Zandjan were collected during 2003 and 2004. 575 and 564 images were prepared from fore and hind wings, respectively. Then 15 and 11 landmarks were determined from fore and hind wings, respectively. With transforming of landmark＇s two dimensional coordinate data into partial warp scores, 26 and 18 scores were generated for fore and hind wings, respectively. Cluster analysis based on wing shape variables using Ward＇s algorithm assigned nine geographical populations into two groups. The pattern of grouping based on fore and hind wings was different in both sexes. Principal component analysis revealed discrimination between geographic populations and confirmed the result of cluster analysis. Among environmental parameters, wind speed showed the highest correlation with wing shape variables. Non significant correlation was observed between geographic and morphological distance matrices as revealed by Mantel test.

On the Dimension for Multivariate Weak Spline Function Spaces

In this paper, the dimension formulaes of multivariate weak spline are discussed. The dimension formulaes of non-degree multivariate weak spline on a vertex are presented. The dimension formulaes on triangulation are also discussed. At last, the local supported bases of W31(I1Δ) are presented.

The Irreducibility and Isomorphism of Piecewise Algebraic Sets

In this paper , we define the piecewise algebraic sets by using multivariatespline functions and discuss their irreducibility and isomorphism problem. We presenttwo equivalent conditions for the irreducibility of piecewise algebraic sets, and turn theisomorphism and classifying problem of piecewise algebraic sets into the isonorphismand classifying problem of commutative algebras.

Asymptotic properties of Lasso in high-dimensional partially linear models

We study the properties of the Lasso in the high-dimensional partially linear model where the number of variables in the linear part can be greater than the sample size.We use truncated series expansion based on polynomial splines to approximate the nonparametric component in this model.Under a sparsity assumption on the regression coefficients of the linear component and some regularity conditions,we derive the oracle inequalities for the prediction risk and the estimation error.We also provide sufficient conditions under which the Lasso estimator is selection consistent for the variables in the linear part of the model.In addition,we derive the rate of convergence of the estimator of the nonparametric function.We conduct simulation studies to evaluate the finite sample performance of variable selection and nonparametric function estimation.

Numerical manifold method based on isogeometric analysis

In this study, numerical manifold method(NMM) coupled with non-uniform rational B-splines(NURBS) and T-splines in the context of isogeometric analysis is proposed to allow for the treatments of complex geometries and local refinement. Computational formula for a 9-node NMM based on quadratic B-splines is derived. In order to exactly represent some common free-form shapes such as circles, arcs, and ellipsoids, quadratic non-uniform rational B-splines(NURBS) are introduced into NMM. The coordinate transformation based on the basis function of NURBS is established to enable exact integration for the manifold elements containing those shapes. For the case of crack propagation problems where singular fields around crack tips exist, local refinement technique by the application of T-spline discretizations is incorporated into NMM, which facilitates a truly local refinement without extending the entire row of control points. A local refinement strategy for the 4-node mathematical cover mesh based on T-splines and Lagrange interpolation polynomial is proposed. Results from numerical examples show that the 9-node NMM based on NURBS has higher accuracies. The coordinate transformation based on the NURBS basis function improves the accuracy of NMM by exact integration. The local mesh refinement using T-splines reduces the number of degrees of freedom while maintaining calculation accuracy at the same time.

A survey on the local refinable splines

This paper provides a survey of local refinable splines,including hierarchical B-splines,T-splines,polynomial splines over T-meshes,etc.,with a view to applications in geometric modeling and iso-geometric analysis.We will identify the strengths and weaknesses of these methods and also offer suggestions for their using in geometric modeling and iso-geometric analysis.

EFFICIENT ESTIMATION OF SEEMINGLY UNRELATED ADDITIVE NONPARAMETRIC REGRESSION MODELS

This paper is concerned with the estimating problem of seemingly unrelated(SU)nonparametric additive regression models.A polynomial spline based two-stage efficient approach is proposed to estimate the nonparametric components,which takes both of the additive structure and correlation between equations into account.The asymptotic normality of the derived estimators are established.The authors also show they own some advantages,including they are asymptotically more efficient than those based on only the individual regression equation and have an oracle property,which is the asymptotic distribution of each additive component is the same as it would be if the other components were known with certainty.Some simulation studies are conducted to illustrate the finite sample performance of the proposed procedure.Applying the proposed procedure to a real data set is also made.

FUNCTIONAL COEFFICIENT AUTOREGRESSIVE CONDITIONAL ROOT MODEL

This paper proposes an extended model based on ACR nmdel： Functional coefficient autoregressive conditional root model （FCACR）. Under some assumptions, the authors show that the process is geometrically ergodic, stationary and all moments of the process exist. The authors use the polynomial spline function to approximate the functional coefficient, and show that the estimate is consistent with the rate of convergence Op（hv＋1 ＋ n-1/3）. By simulation study, the authors discover the proposed method can approximate well the real model. Furthermore, the authors apply the model to real exchange rate data analysis.