四次Said-Ball曲线的扩展

给出了一个含有参数λ的五次多项式基函数,是四次Said-Ball 曲线基础函数的扩展;分析了此基函数的性质,基于该组基函数定义了带有形状参数的多项式曲线.曲线不仅具有四次Said-Ball 曲线的特性,而且具有形状的可调性和更好的逼近性.参数λ有明确的几何意义:λ越大,曲线越逼近控制多边形;当λ=0时,曲线退化为四次Said-Ball曲线.还讨论了两段曲线C1连续拼接的条件.实例表明,定义的曲线的形状是随着λ取不同的值而发生变化.     

带双参数四次Said-Ball曲线的扩展

为了使曲线易于实现光滑拼接,同时具有对应于相同控制顶点的不同形状,定义了具有凸包性、对称性、形状可调性等基本性质的新曲线.文中分析了基函数及曲线的性质和2个形状参数的几何意义,给出了2条Said-Ball型曲线的G0,G1,G2连续拼接条件.类似构造了局部形状可调的组合曲面.数值实例说明了所给方法的正确性和有效性.     

带有切线多边形的三次B样条的α扩展曲线

为了使三次均匀B样条的α扩展曲线与给定多边形相切,构造了一种与给定多边形相切的三次均匀B样条曲线的α扩展的算法.在算法中,所有的三次均匀B样条的α扩展曲线的控制点可以通过对多边形的顶点简单计算产生.所构造的曲线对多边形具有保形性,曲线可以局部修改.最后给出了2个算例.     

有理三次Bezier曲线的参数化研究

应用重心坐标推导出有理三次Bezier曲线的表达式，通过给定的4个控制顶点和位于这些顶点凸包内三次有理曲线上的一点，反算出了该点的参数和内权因子．研究了在保持曲线形状不变的条件下，空间有理三次Bezier曲线权因子变换和参数变换的等效性。     

腰果形状参数对分级成功率的影响

文章通过测量大量的腰果形状参数,并通过origin软件对各项参数进行分析,确定出以长度代替腰果宽度进行分级,根据长度计算出各级腰果所占的比例,计算表明很大或者很小的腰果所占的比例很小,二级果的分选成功率为60.93%,三级果的分选成功率为22.64%。当对筛孔宽度为19mm时计算分级成功率,得出成功分级的腰果所占比例为83.57%。     

基于手机拍照和ImageJ软件的大米外观形状参数的测定

大米外观形状参数是大米品质和品种分类标准的重要特征之一,目前GB/T 17891—2017中对大米的粒型、外观检测的方法还停留在人工检测阶段。虽然有大米外观品质判定仪设备,但其价格昂贵、操作繁琐。本研究利用手机拍照获取图形,通过ImageJ软件进行图像处理,提出了一种简单、准确、快速的大米外观品质相关特征量的测定方法。与人工检测和大米外观品质判定仪的测定结果进行了比较,证明了该方法优于人工检测,与仪器相当,最后通过该方法对比分析了东北大米和湖南大米的外观品质。该方法简单方便,开发手机App后可在粮食企业和检测机构获得广泛应用。     

热风炉设计参数计算中计算机的应用

热风炉设计参数计算中计算机的应用管建红孙承业（杭州茶叶机械总厂３１１４０４）一、引言热风炉是我厂的主要产品之一。在以往的热风炉设计计算中，我们采用的是区域平均近似计算法，不仅计算工作量大，而且与实际数值有一定的偏差。其原因是：在计算的未知参数中，传热...     

圆锥筒子卷绕曲线的分析与设计

本根据圆锥筒子卷绕密度均匀的要求,利用微分方程推导出满足这一要求的卷绕曲线的方程,并给出了避免重叠的方法。     

加热室管板钻孔的钻头刃磨形状和几何参数

本文介绍黄铜管板的钻孔工艺,在研究和试验基础上,对钻头研磨和钻削速度等方面摸索了一套经验,提高了管板加工质量和速度。     

基于参数化技术的图案设计综述

参数化、变量化技术是学术界、产业界的一个交叉学科研究热点。分析了包括形状语法、分形理论、数学模型等参数化图案设计的理论和方法,讨论与比较了建筑、产品以及图案设计3个领域的参数化设计语言。在此基础上,总结了在理论算法、设计流程以及参数化软件方面的共性,为图案设计的发展与多样性提供新的驱动力。针对服装图案特性,研究了参数化技术的应用现状与难题,提出了参数化技术在图案设计领域未来的发展方向。     

羊毛衫衣片曲线的控制与应用

对影响羊毛衫衣片曲线形状的因素进行研究,以掌握衣片曲线的成形规律。通过结合款式和收放针搭配规则要求,利用计算机软件的方格图进行作图,对实际收放针效果的曲线形状进行模拟,形成收放针效果模拟图,并根据作图效果得到收放针搭配方式。通过这种方法,可以直观地看出收放针成形效果和得到收放针搭配方式,也可以根据收放针搭配方式制作收放针成形效果图。分析了收放针搭配方式中段数、次数、斜率变化对曲线形状的影响,并得到结合直线拟合曲线规律进行收放针搭配的方法。     

Using geometric morphometrics for the genetics analysis of shape and size of lactation curves in Israeli first-parity Holstein cattle

Our objective was to combine the methods of geometric morphometrics and multivariate quantitative genetics to genetic evaluation of the size and shape of lactation curves of milk of 3,492 Israeli first-parity Holstein cattle. Lactation records were treated as morphological data, for which 2 different lactation shape functions were evaluated, one depicted by a line graph and the other by an orbital graph. The lactation curves from both shape functions were represented by 2-dimensional Cartesian landmark coordinates. The 2 sets of landmarks were then analyzed individually for each shape function with geometric morphometrics to separate variation into components of size and shape. The analysis yielded 2 size measures and 2 sets of shape variables, and they were the inputs to estimate variance components using the MTC REML individual animal model program. Variance components were also estimated for the 305-d lactation production as a reference. Shape variables showed negligible correlation with 305-d production, providing evidence of size and shape of lactation curve as separate characters. The size measure derived from the orbital-depicted lactation curve had equal heritability (0.39 ± 0.01; ± standard error) and complete genetic and environmental correlations with 305-d production, whereas the size measure derived from the line-depicted lactation curve showed low heritability (0.09 ± 0.01) and environmental correlation (0.02 ± 0.004) and relative high genetic correlation with 305-d production (0.48 ± 0.04). This may validate both the orbital graph to depict lactation records and the use of geometric morphometrics to split variation of lactation curve into size and shape components. The maximal heritability for shape of lactation curve was 0.55 for orbital- and 0.56 for line-depicted lactation curves. The respective patterns of variations were visualized as shape changes from the mean shape in the data set. Geometric morphometrics are well grounded within the theory of shape analysis and can be paired with conventional methods in the field to characterize the patterns of phenotypic and genetic variation of shape and size of lactation curve in dairy cattle.     

Effects of inulin,fructooligosaccharides/glucose and pH on the shape of the death kinetic of Lactobacillus reuteri DSM 20016

The viability of Lactobacillus reuteri, Lb. delbrueckii subsp. bulgaricus and Lb. paracasei was assessed in a laboratory medium containing inulin (5 g L^?1) or glucose + FOS (fructooligosaccharides) (2.5 + 2.5 g L^?1). Data were modelled through the Weibull equation pinpointing that prebiotics determined a decrease in the shape parameter. In the 2nd step, L. reuteri was used as the test microorganism; pH, storage temperature and the amounts of FOS + glucose and inulin were combined through a 4‐variable/5‐level central composite design. Temperature, pH and glucose + FOS affected the microbiological shelf life; inulin was not significant. The maximum value of shelf life was found at pH 8.5 and with 5.0 g L^?1 of glucose + FOS. The combination of pH and prebiotics affected the shape parameter with a shift from a convex to a concave trend and vice versa: their effect was different depending on the use of a single prebiotic or a mix.     

文胸的造型结构与人体塑型探讨

通过文胸的造型发展及其造型结构对人体塑型的功效,探讨了文胸造型结构设计的原理与人体相吻合的关系,使文胸造型可塑造不同要求的人体外型美。提出了CAD服装结构设计系统应注重人性化功能的应用。     

多功能馒头机的成型系统设计

在分析了圆形、方形馒头成型机理的基础上,阐述了多功能馒头机成型系统的工作原理,并详细介绍了其主要机构及设计原理和特点。     

Detection of different shapes of lactation curve for milk yield in dairy cattle by empirical mathematical models

The study of relationships between mathematical properties of functions used to model lactation curves is usually limited to the evaluation of the goodness of fit. Problems related to the existence of different lactation curve shapes are usually neglected or solved drastically by considering shapes markedly different from the standard as biologically atypical. A deeper investigation could yield useful indications for developing technical tools aimed at modifying the lactation curve in a desirable fashion. Relationships between mathematical properties and lactation curve shapes were analyzed by fitting several common functions (Wood incomplete gamma, Wilmink's exponential, Ali and Schaeffer's polynomial regression, and fifth-order Legendre polynomials) to 229,518 test-day records belonging to 27,837 lactations of Italian Simmental cows. Among the best fits (adjusted r(2) higher than 0.75), the 3-parameter models (Wood and Wilmink) were able to detect 2 main groups of curve shape: standard and atypical. Five-parameter models (Ali and Schaeffer function and the Legendre polynomials) were able to recognize a larger number of curve shapes. The higher flexibility of 5-parameter models was accompanied by increased sensitivity to local random variation as evidenced by the bias in estimated test-day yields at the beginning and end of lactation (border effect). Meaning of parameters, range of their values and of their (co) variances are clearly different among groups of curves. Our results suggest that analysis based on comparisons between parameter values and (co)variances should be done carefully. Comparisons among parameter values and (co)variances could yield more robust, reliable, and easy to interpret results if performed within groups based on curve shape.     

针织毛衫立体造型设计探讨

随着个性化、时尚化、内衣外穿因子的注入,针织毛衫的立体造型设计越来越强调"服装是人体的软雕塑"的理念.文章介绍了针织毛衫立体造型设计的重要性,重点分析了各种面料线材、不同组织结构、不同材质组合搭配和独特的工艺设计手段在针织毛衫立体造型中的运用.旨在丰富毛衫的艺术表现力,拓展毛衫的空间造型潜力,为毛衫设计师提供更广阔的灵感来源和创作思路.     

服装袖型结构与人体上肢穿着适应性研究

服装袖型结构是依托人体上肢为原型而展开的物态空间体,对其进行研究有利于解决衣袖结构与上肢功能适应性问题。基于上肢形态、关节驱动等特点,将其划分为"臂根、肩部上凸面"、"臂根、胸侧下凹面"、"肘关节隐形前凹面"和"腕关节隐形前凹面"等4个结构部位点,并采用立体裁剪的方法,对4个部位点进行了分析研究。结果表明:服装袖型不仅是单一的上肢包装物,也是一个能容纳和包容多个复杂多变"曲面凹凸体"的椭圆桶状物。合理把握人身体与上肢结构功能关系,设计袖子结构中袖窿、袖山、袖肘、袖腕的"量",确保袖子内部结构能满足身体功能。