线切割设备工艺曲线计算方法的优化与应用

论述了圆弧式数据曲线的计算方式与方法,该算法通过软件产品予以实现,主要用来优化线切割设备的工艺设定方式与工艺曲线计算方法,最终达到增强设备稳定性的目的。

两种活塞环外型曲线计算方法的比较

本文对采用Коган压力分布式的两种活塞环型线计算方法进行比较,并从个人观点指 出哪种方法更有利。

径向剃齿刀齿向凹形量的双曲线计算方法

日本五十铃汽车齿轮变速箱的传动齿轮常常有齿向鼓形量的要求,精加工有齿向鼓形量要求的传动齿轮常常采用径向剃齿加工方法。根据径向剃齿加工原理,要加工出传动齿轮的齿向鼓形量,就必须确定好径向剃齿刀的齿向凹形量,使剃齿刀的齿向凹形曲线与传动齿轮对应的齿向鼓形曲线完全一致。问题的关键是,如何根据齿向鼓形量确定其齿向鼓形曲线?如果确定了齿轮的齿向鼓形曲线,那么其他问题就迎刃而解。

利用二次曲线束求解二次曲线的计算方法研究

利用二次曲线进行物体识别、场景重建及运动分析是计算机视觉中非常活跃的一个研究领域。传统的方法是通过二次曲线上的多个点或多条直线求解二次曲线。但在实际应用中,有时既检测曲线上的点,又检测曲线上的直线,因此必须建立一个统一的二次曲线算法。为此,提出了二次曲线束基的概念,给出了不同条件下利用二次曲线束求解二次曲线的具体计算方法。实验表明算法实用和可靠。

复合曲线坐标计算方法浅析

通过图示,介绍了直线、圆曲线、缓和曲线的坐标计算方法及线型的通用表示方法,并使用通用符号,通过编程简化计算过程,大大提高了测量工作效率。

直埋供热管道散热损失简化计算方法

为了准确预测城市热水集中供热管网动态热力工况,必须准确计算供热管道散热损失。现有的计算公式均比较复杂,不便于供热管网动态热力工况的计算分析。因此,本文在对目前国内外通用的直埋热水供热管道散热损失计算公式比较、分析的基础上,提出采用最小二乘法进行多项式拟合,建立仅以热水温度为变量的供热管道散热损失线性方程,并对不同管径、不同保温材料进行了计算分析。结果发现,各计算公式的偏差主要由热阻的计算范围不同所导致。简化后的拟合公式与选用公式的相对误差均在3%以内,可以满足工程应用的要求。

基于分布式光纤传感的海底管线横向屈曲识别方法

针对传统海底管线横向屈曲识别方法无法真实反映海底管线结构状态的问题,本文以含初始缺陷的海底管线作为研究对象,基于分布式光纤传感获得的海底管线分布式结构响应,采用Euler-Bernoulli梁挠曲线计算方法建立管道屈曲位移重构算法,实现了荷载未知情况下海底管线前、后屈曲行为的定量识别。以初始缺陷幅值作为变参数,采用初始缺陷海底管线有限元分析与模型实验验证提出方法的可行性。结果表明:本文基于分布式光纤传感提出的海底管线横向屈曲位移重构算法可定量识别海底管线横向屈曲的产生及发展过程,为解决未知荷载作用下海底管线横向屈曲识别问题提供了一种可行的方法。

Invertibility of Infinite-Dimensional Hamiltonian Operators and Its Application to Plate Bending Equation

The results of invertibility and spectrum for some different classes of infinite-dimensional Hayniltonian operators, after a brief classification by domains. are given. By the above results, the associated infinite-dimensional Hamiltonian operator with simple supported rectangular plate is proved to be invertible. Furthermore, by a certain compactness, we find that the spectrum of this operator consists only of isolated eigenvalues with finite geometric multiplicity, which will play a significant role in finding the analytical and numerical solution based on Hamiltonian system for a class of plate bending equations.

An efficient method for tracing planar implicit curves

This paper presents a method for tracing a planar implicit curve f（x, y）=0 on a rectangular region based on continuation scheme. First, according to the starting track-point and the starting track-direction of the curve, make a new fimction F（x, y）=0 where the same curve withf（x, y）=0 is defined. Then we trace the curve between the two domains where F（x, y）〉0 and F（x, y）〈0 alternately, according to the two rules presented in this paper. Equal step size or adaptive step size can be used, when we trace the curve. An irregular planar implicit curve （such as the curve with large curvatures at some points on the curve）, can be plotted if an adaptive step size is used. Moreover, this paper presents a scheme to search for the multiple points on the curve. Our method has the following advantages： （1） it can plot Co planar implicit curves; （2） it can plot the planar implicit curves with multiple points; （3） by the help of using the two rules, our method does not need to compute the tangent vector at the points on the curve, and directly searches for the direction of the tracing curve; （4） the tracing procedure costs only one of two evaluations of function f（x, y）=0 per moving step, while most existing similar methods cost more evaluations of the function.

The Complex Analysis Method of Numerical Identification of Parameters of Quasiideals Processes in Doubly-Connected Nonlinear-Layered Curvilinear Domains

The method of numerical solving of nonlinear model problems of theory of a complex quasi-potential in doubly-connected nonlinear-layered curvilinear domains considering inverse influence function of flow on a conductivity coefficient of medium was developed on the basis of synthesis of numerical methods of the quasi-conformal mappings and summary representations in conjunction with domain decomposition by method Schwartz. The proposed algorithm allows finding the potential of the quasiideals field, construction a motion grid （fluid-flow grid） simultaneously defining the flow lines that separate of sub-domains constancy of coefficient conductivity and identification the piecewise-constant values of coefficient conductivity, the local flows for the known measurements on boundary of domain.

The Hyperbolic Darboux Image and Rectifying Gaussian Surface of Nonlightlike Curve in Minkowski 3-Space

In this paper,we give the classification of the singularities of hyperbolic Darboux image and rectifying Gaussian surface of nonlightlike curve in Minkowski 3-space.We establish the relationship between the singularities and the geometric invariants of curves which are deeply related to its order of contact with helices.

Some Researches on Real Piecewise Algebraic Curves

The piecewise algebraic curve,defined by a bivariate spline,is a generalization of the classical algebraic curve.In this paper,we present some researches on real piecewise algebraic curves using elementary algebra.A real piecewise algebraic curve is studied according to the fact that a real spline for the curve is indefinite,definite or semidefinite(nondefinite).Moreover, the isolated points of a real piecewise algebraic curve is also discussed.

Sufficient Conditions for Heegaard Splittings with Disjoint Curve Property

In the paper,we give two conditions that the Heegaard splitting admits the disjoint curve property.The main result is that for a genus g(g■2)strongly irreducible Heegaard splitting(C_1,C_2;F),let D_i be an essential disk in C_i,i=1,2,satisfying(1)at least one of ■D_1 and ■D_2 is separating in F and|■D_1∩■D_2|■2g-1;or(2)both ■D_1 and ■D_2 are non-separating in F and|■D_1∩■D_2|■2g-2,then(C_1,C_2;F)has the disjoint curve property.

Semipositivity of generic ordinary fibration over a curve

Let f : X → B be a generic ordinary proper fibration over a complete curve in positive characteristics, we prove that the dual of higher direct image sheaf R^1 f_*O_X is nef. As a corollary, we show that f_*ω_(S/B) is nef, if f : S → B is a fibration from a surface to a curve with generic ordinary fibres.