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。     

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。     

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...     

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。     

高吸湿纤维的吸附—解吸等温曲线参数的分析

不同织物服装的卫生性和舒适感在很大程度上决定于纤维的吸湿性。纤维材料在加工、储藏和使用过程中,总是暴露于一定的湿度和温度环境中,由于许多纤维材料对湿度很敏感,因此在加工过程中它们的形状、尺寸会发生改变。另外制品的力学性能也与纤维和纱线的吸湿率成函数关系,这种情况在很大程度上     

Short communication: Selection for persistency by changing the shape of lactation curves with geometric morphometrics

The objective was to simulate the response to selection by modifying the shape of the lactation curve to improve persistency in Israeli first-parity Holstein cattle using geometric morphometrics and multivariate quantitative genetics. The 2-dimensional Cartesian coordinates representing the shape of the lactation curve were characterized using geometric morphometrics. Genetic parameters of daily milk yield were estimated for the individual animal model using REML. Results of selection were simulated using the multivariate breeders' equation. We defined 6 selection regimens: (1) decrease in the third month in milk (MIM), (2) increase in the ninth MIM, (3) decrease in the third MIM and increase in the ninth MIM, (4) decrease in the first MIM, (5) decrease in the second MIM, and (6) decrease in the fourth MIM. The first 3 selection criteria targeted changes in the MIM of previous measurements of persistency in the Israeli Holstein population, and the last 3 targeted the months with the highest variability. All selection regimens attempted to modify the shape of the lactation curve while keeping total milk yield constant. The first 3 selection regimens showed greater total responses, with the highest response for decrease in the third MIM and increase in the ninth MIM. Magnitudes of correlated responses consistently surpassed direct responses in all selection criteria, suggesting that selection on specific parts of the lactation curve would produce correlated responses in other parts. Predicted responses to selections were depicted as shape changes from the mean shape in the data set. Most predicted responses demonstrated a fairly similar shape compared with the lactation curve. The predicted responses of lactation shapes of the last 3 selection regimens were overall lower in the first 3 MIM and decreased less in the last MIM, demonstrating a much flatter shape and thus improved persistency.     

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.     

Scleral shape and its correlation with corneal parameters in keratoconus

PurposeTo assess the correlation of the scleral shape and corneal tomographic parameters in keratoconus.MethodsTwenty eyes of 15 keratoconus patients with no previous specialty lens wear or ocular surgery were included in this study. Corneal imaging was obtained with the Pentacam HR and three-dimensional (3D) corneoscleral maps were acquired using the Eye Surface Profiler, ESP. Sagittal height was calculated at the central corneal level (annulus of 0–4 mm radius), peripheral cornea (annulus 4–6 mm radius) and sclera (annulus 6–8 mm radius) using ESP maps and Pentacam HR (exclusively for the central cornea). The flattest and steepest regions of each annulus and the circumferential scleral asymmetry were calculated based on custom-made software. The Pearson correlation coefficient (r) was used to evaluate the correlation between corneal parameters as measured by Pentacam HR and scleral asymmetry.ResultsAnterior corneal parameters, such as flattest and steepest keratometry, were found to be correlated with scleral asymmetry in keratoconus (all r>0.5, p < 0.05). In contrast, anterior astigmatism showed poor correlation with the level of scleral irregularity (r=-0.11; p = 0.32). Other disease-specific parameters pertaining to the posterior corneal curvature and corneal thickness were not correlated with scleral asymmetry. The steepest regions of the central cornea, peripheral cornea, and sclera tended to share a common angle (r = 0.92; p < 0.001 for central cornea compared to sclera).ConclusionAnterior corneal parameters measured by corneal imaging are associated with the level of scleral asymmetry and the orientation of the steepest area of the sclera in eyes with keratoconus.     

A字裙造型与面料性能的关系

为研究A字裙造型与面料性能之间的量化关系,选用15种常见面料,测试了面料的常见物理力学性能,并用同一样板制作A字裙,用数码相机对A字裙从不同角度进行拍照,然后用Photoshop进行图像处理,提取A字裙不同方向像素面积、裙宽、裙厚、波浪个数等造型参数指标,最后用相关分析和回归分析进行数据处理。研究结果表明：影响A字裙造型客观的面料性能有弯曲刚度、拉伸率、面密度及悬垂性;裙厚及侧面面积与面密度呈正相关;45°侧面面积与纬向抗弯刚度正相关;面料越不易拉伸的面料制成的A字裙越易呈现下摆向两侧张开的A型效果;硬挺、悬垂性差的面料制成的A字裙波浪数较少。     

利用织物实际弯曲形态测试其弯曲性质的算法

介绍了织物弯曲理论和测试方法的研究现状,提出了一种利用织物在自重作用下的实际弯曲形态间接测试织物弯曲性质的测试方法。详细叙述了该方法的测试原理,在此基础上利用数学多项式回归和微积分方法对实际弯曲形态曲线上的信息进行计算处理,提出了织物在自重作用下的弯矩与曲率、弯曲刚度与曲率关系的算法。利用此方法对织物进行测试,取得了很好的结果,与KES方法测试得到的弯曲刚度值对比,获得了很好的相关性验证。     

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.