梯形明渠正常水深直接计算公式

通过对梯形明渠均匀流基本方程的数学变换，得到计算其无量纲正常水深λ的迭代公式，一方面从数学上证明了迭代函数的收敛性，另一方面，通过对无量纲正常水深λ与已知参数ｍ，ａ之间关系的分析及数值计算，利用最佳逼近拟合原理得到无量纲正常水深的一次近似计算式，最后以此近似计算式为初和迭代方程进行一次迭代得到梯形明渠无量纲正常水深的直接计算公式，计算实例表明此方法简捷、准确且不需依赖图表。     

梯形断面抗滑桩桩间距计算方法研究

针对滑坡治理新方法——梯形断面抗滑桩,分析了梯形断面抗滑桩土拱效应的形成机理,建立了梯形断面抗滑桩桩间距计算模型。将该类桩的土拱效应视为两个独立的土拱作用,利用土体极限强度、拱脚强度以及桩间静力平衡推导了相应的桩间距计算公式。实例分析表明,梯形断面抗滑桩桩间净距比其他矩形桩桩间净距大,说明梯形抗滑桩斜边的存在使土拱效应整体效果得到加强,梯形抗滑桩相较于其他形式的抗滑桩具有更好的抗滑效果。     

梯形透空丁坝局部水动力特性对底栖动物生境演替的影响机制

针对因梯形透空丁坝局部水动力特性对底栖动物栖息地的影响机制尚不明确,限制了此类结构的大范围推广应用的问题,依托长江深水航道建设的示范应用工程,构建三维水动力数值模型,选择中华绒螯蟹为指示物种,研究了不同径流条件下梯形透空丁坝局部水动力特性及其对指示物种栖息地的影响;结合梯形透空丁坝不同时期沉积物和底栖动物的监测数据,分析了梯形透空丁坝对底栖动物生境演替的影响机制。结果表明：梯形透空丁坝迎流面产生的上升流将主流引导至丁坝后上方,在汛期为中华绒螯蟹提供了避洪场所;坝内及坝后较小的流速和丰富的流场结构为中华绒螯蟹提供了索饵场和越冬场。     

彩色梯度相移与格雷码相结合的三维测量方法

为了实现高分辨率快速非接触式三维测量,将彩色梯度相移法与格雷码相结合,提出了三维测量算法。将一幅彩色梯形三步相移图案和两幅彩色格雷码图案相结合,对测量空间进行编解码;通过两幅彩色格雷码图案将测量空间可靠地分成64个子空间,通过一幅重复彩色梯形三步相移图案将每个子空间分成6个区域,每个区域再通过强度比细分到像素级。给出了编码图案和解码公式,组建了彩色结构光三维测量系统,并分别采用彩色梯形相移法和本文提出的方法对深度为700～950nm的平面进行了仿真和实际测量。理论分析、仿真与实际测量结果表明,得到的测量平均误差0.9mm,测量标准差1.2mm。最后,采用本文方法对石膏和人体进行了测量实验,结果显示该方法具有抗干扰能力强、运算速度快的优点。     

梯形螺纹宏程序的数控仿真加工

介绍了VNUC数控加工仿真软件的仿真加工过程.通过搭建数控车床模型、安装工件、安装刀具、载入程序文件等的仿真环境,尝试用35°硬质合金外圆精车刀加工梯形螺纹,并进行工艺分析与程序设计.利用VNUC软件支持的宏程序功能对梯形螺纹程序仿真并验证,加工的螺纹效果很好.     

弧形坡脚梯形渠道混凝土衬砌技术

介绍了弧形坡脚梯形渠道混凝土衬砌技术在大型灌区节水工程中的实际应用,详细叙述了各工序的施工工艺,对加快施工速度、提高工程质量提出几点意见。     

基于聚类分组的模糊查询控制

本文提出了一种模糊查询控制的模型,这个模型吸收了两种思想,即有穷自动机思想和聚类分组算法,基础是采用了分组算法。模型分为两个部分,第一部分是对原始数据的分析,为后面的查询控制做准备,第二部分则是具体的模糊查询控制。     

A comparison of mental retardates and normals on the rotating trapezoidal window illusion.

56 high-grade institutionalized adolescent retardates and 56 normals of equated CA were, after training, split into 4 groups: Groups I and II observed a rotating trapezoidal window monocularly and binocularly, respectively; Groups III and IV observed a rotating trapezoidal shape, which had no windows cut out or shadows painted on it, monocularly and binocularly, respectively. Analysis of variance shows that visual conditions and stimuli are significant, but groups are not. The finding that retardates do not differ from normals on a reduced-cue ("experiential") illusion, contrasts with previous findings that they differ on full-cue ("physiological") illusions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An implicit boundary element solution with consistent linearization for free surface flows and non‐linear fluid–structure interaction of floating bodies

In this work, a new comprehensive method has been developed which enables the solution of large, non‐linear motions of rigid bodies in a fluid with a free surface. The application of the modern Eulerian–Lagrangian approach has been translated into an implicit time‐integration formulation, a development which enables the use of larger time steps (where accuracy requirements allow it). Novel features of this project include: (1) an implicit formulation of the rigid‐body motion in a fluid with a free surface valid for both two or three dimensions and several moving bodies; (2) a complete formulation and solution of the initial conditions; (3) a fully consistent (exact) linearization for free surface flows valid for any boundary elements such that optimal convergence properties are obtained when using a Newton–Raphson solver. The proposed framework has been completed with details on implementation issues referring mainly to the computation of the complete initial conditions and the consistent linearization of the formulation for free surface flows. The second part of the paper demonstrates the mathematical and numerical formulation through numerical results simulating large free surface flows and non‐linear fluid structure interaction. The implicit formulation using a fully consistent linearization based on the boundary element method and the generalized trapezoidal rule has been applied to the solution of free surface flows for the evolution of a triangular wave, the generation of tsunamis and the propagation of a wave up to overturning. Fluid–structure interaction examples include the free and forced motion of a circular cylinder and the sway, heave and roll motion of a U‐shaped body in a tank with a flap wave generator. The presented examples demonstrate the applicability and performance of the implicit scheme with consistent linearization. Copyright © 2001 John Wiley & Sons. Ltd.     

基于梯形波分析信号的一种新方法

本文以电子学中的一种常见波形——梯形波为研究对象,考虑了它的主要性质,并利用双正交性质,研究了一个信号如何才能表示成梯形波形式的问题.对非正交函数的研究是信号分析理论的有益补充.