犁体曲面的计算机辅助设计研究

犁体曲面的计算机辅助设计研究吕钊钦山东农业大学１前言设计犁体曲面的主要途径有在试修法基础上进行测绘获得犁体曲面和用几何作图法与数学分析法设计犁体曲面。常用的几何作图法为水平直线元法，该法应根据给定的土垡几何尺寸ａ和ｂ绘制犁体曲面外形轮廓主视图；确定元...     

采用地震目录构建南美消减带的三维形态

利用ISC(International Seismological Centre)编辑的地震目录,对南美消减带形态进行研究,给出了俯冲带的三维形态。通过观察我们发现大量地震发生在消减带的附近,我们假定俯冲带为一个曲面,而震源沿着曲面分布,借此我们可以反演俯冲带的几何形态。首先我们处理了ISC地震目录里面的数据,再通过拟合处理过的地震数据,而得出的三维形态。     

数字化服装立体裁剪方法研究

"服装是艺术与几何空间的完美结合",这一点在服装立体裁剪中得到了充分体现。为了合理地进行服装曲面的结构处理,必须深入研究人体及服装的曲面形状,研究如何利用平面材料的几何变形完成服装曲面的构造。三维服装CAD正是要实现服装曲面的构造及其展开,因而必须从立体裁剪过程中抽象出其几何特征,以实现数字化操作。本文根据服装原型在服装裁剪中的核心作用及其立体裁剪所具有的几何学特征,以日本文化式女装原型为研究对象,提出了实现服装原型数字化立体裁剪的几何学方法。     

空间二次代数曲面的最优有理参数化

利用三角形网格均匀面积参数化的思想,提出了有理参数曲面上曲面片的最优参数化评判标准。根据构造具有几何意义的二次代数曲面有理参数化方法,确定了二次代数曲面上指定曲面片的最优或逼近最优的有理参数化方程。最后通过实例对该方法与传统方法得到的参数化结果进行了对比。     

翻领成型器曲面几何形状研究

翻领成型器曲面为可展曲面,用微分几何方法描述了翻领成型器曲面的数学模型,推出了肩曲面为左右对称顶点不同的锥面时的圆形料管翻领成型器的交接曲线以及边界曲线的数学模型,并用Pro/E建立其三维曲面参数化数字模型,为翻领成型器其他截面形状、其他曲面形状的研究提供新的研究方法,为翻领成型器设计制造提供一定的理论依据。     

基于点模型的织物平整性能分析

为客观评价织物的平整度等级,给出一个基于点模型的织物平整性能分析流程。首先以三维高精度激光扫描仪上获取的织物离散数据点为研究对象,引入点模型的分析方法,筛选出反映织物表面起伏与否的特征点及其邻域点集,并在特征点邻域重构MLS曲面。然后,依据离散微分几何中的曲面理论,计算特征点在重构曲面上的高斯曲率和平均曲率,用曲率值的大小客观表达特征点处局部曲面的屈曲类型和弯曲程度。实验数据表明,织物点模型特征点处的曲率值揭示了点模型所代表的织物表面的褶皱起伏程度和尖锐程度,合理反映了织物的平整性能,可以为客观评价织物的平整度等级提供依据。     

文胸模杯曲面形态特征曲线提取与分析

为获得控制文胸模杯曲面形态的特征曲线,实现模杯的正向设计,采用三维扫描仪获取模杯的点云数据,用逆向工程软件进行实体模型构建,然后根据模杯角度及特征点构建了26条模杯内外曲面形态曲线。利用各曲线拐点、峰值点、曲率最大点及最小点的分布位置一致性,提取能够反映模杯曲面特征信息的内外曲面形态特征曲线5条。结果表明:模杯结构特征曲线上的几何参数分布离散程度更小,较角度特征曲线更能反映不同类型模杯的曲面形态特征。拟合各特征曲线弧长与模杯杯深的函数关系,通过改变形态特征曲线上的几何参数可控制曲面形态结构。     

三维服装原型可展化方略

文中根据服装原型在服装裁剪中的核心作用，以及立体裁剪所具有的几何学特征，提出实现服装原型曲面可展化进而完成服装原型曲面几何造型的策略与方法，并对日本文化式女装衣身原型进行了可展化操作，建立了其服装原型的几何造型。可展化方略为：立足边框线，着眼至高点，填平补凹设省道，近似处理非可展。     

水平动线犁体曲面解析

水平动线犁体曲面的工作性能,主要决定于水平动线的曲导线和动线与沟壁夹角θ的控制曲线。本文试图用解析法分析这两条曲线的几何性质对犁体曲面工作性能的影响,为两条曲线的选择提供一点理论分析的依据,同时建立犁体曲面及有关曲线的方程,供设计研究参考。     

基于语义分析的三维服装曲面生成算法

为进一步提高三维服装设计效率,提出了一种基于语义分析的三维服装曲面生成算法。首先分析了基于网格模式的几何交互语义,通过服装曲面网格化处理,将草图勾绘映射到三角网格上,确定草绘点与网格点之间的对应关系;然后通过几何语义交互模式建立起草绘图与网格图的映射关系,利用逼近拟合算法完成对草绘线的拟合,并通过光滑、去噪、网格拼接等方法形成完整的三维服装曲面;最后选取几何模型法、约束模型法与语义分析法进行对比实验,将3种算法各自完成100 步拟合后分别计算其拟合准确度。结果表明,本文所提算法的运行效率比其他主流算法高出近45%,拟合准确度高出近15%。     

皮蛋壳表层红色斑块成分的分析与鉴定

目的 分析鉴定皮蛋壳表面红色斑块物质组成成分, 为控制红斑生成提供理论依据。方法 采用场发射扫描电镜(Scanning Electron Microscope, SEM)、X射线衍射仪(X-ray Diffractometer, XRD)、X射线电子能谱仪(X-ray Photo-electron Spectroscopy, XPS)分析皮蛋壳表面红色斑块的微观结构和化学成分。结果 皮蛋壳表面红色斑块物质是大块片状物附着在粗糙的碳酸钙晶体外层, 蛋壳气孔也被块状异物堵塞, XPS检测出红斑由C、O、N、Na、Ca、Fe、Cu、S、Zn、P等元素组成, Fe元素含量低, 未检出Pb元素; XRD分析确定红斑的主要物质是Cu2O, 红斑外层Cu+因氧化而成Cu2+。结论 皮蛋壳表面红色斑块主成分为Cu2O。采取鸭蛋消毒控菌, 低温避光腌制或许可控制蛋壳红斑形成。     

Involvement of actin and polarisome in morphological change during spore germination of Saccharomyces cerevisiae

We studied the morphological changes of Saccharomyces cerevisiae ascospores during germination. Initiation of germination is followed by polarization of actin patches, maintaining their localization to the site of cell surface growth. Loss of polarisome components, Spa2p, Pea2p, Bud6p or Bni1p, results in depolarization of actin patches. Green fluorescent protein-fused polarisome components exhibit the polarized localization, implying that polarisome is involved in the polarized outgrowth during germination. At the late stage of germination, we found that actin patches temporally depolarize before bud emergence. The observation that loss of Cla4p extends the polarized growth period suggests that Cla4p is involved in the actin-depolization step. Actin polarization in the initial stage is accelerated by overexpression of Ras2p, whereas hyperpolarization is continuously observed by overexpression of Rho1p. Thus, yeast spore germination is a morphological event that is regulated by a number of factors implicated in mitotic bud morphogenesis.     

Patch exploitation by Tribolium castaneum: movement patterns, distribution, and oviposition

Stored-product insects often live in an environment of spatially separated food patches that vary considerably in size, quality, and persistence. The movement of individuals among patches of food influences the probability that stored products will become infested and pest populations will persist within storage facilities, thus affecting many aspects of pest management. We examined how a major stored-product pest, the red flour beetle, Tribolium castaneum (Herbst), exploits patches of food. Individuals are often inactive, periods of inactivity are often outside of food patches, males are more likely to be inactive outside of flour patches than females, and there is considerable variation among individuals in the time spent outside of patches. Beetles outside of food patches tend to be observed near edges due to a tendency to be inactive at edges, to move along edges, and to move more slowly when moving along edges. This tendency to move along edges makes beetles more likely to infest flour patches near the edges than patches further from the edge. A better understanding of the influence of landscape on pest behavior, spatial distribution, and population dynamics is needed to develop effective stored-product pest IPM programs.     

丝素蛋白/聚左旋乳酸纳米纤维纱线肌腱补片的制备及其性能

针对用于纺织肌腱补片的纯微米纱线结构生物活性低、免疫原性强和不可降解的缺陷,从补片材质和结构优化角度出发,构建了几种可生物吸收的纳米结构肌腱补片,以自制的丝素蛋白(SF)/聚左旋乳酸(PLLA)纳米纤维纱线为纬纱,以传统PLLA微米纤维纱线为经纱,经机织工艺加工成形。系统研究了SF和PLLA组分配比对补片形态结构、理化性能以及生物性能的影响。结果表明:补片均在约16.4°出现了结晶衍射峰,且随着SF占比的增加,补片的结晶度和力学性能均逐渐降低,但其断裂载荷均在100 N以上,可满足实际应用需求,且补片的细胞黏附和增殖能力均随SF质量分数的增加逐渐增强。     

时-空域多特征证据学习与增强的印染疵点在线检测

 提出了一种基于时空域多特征证据学习与增强的织物印染疵点在线检测新方法。利用多种类纹理特征在特征表达上的互补性以及可疑图像分块前n帧历史的对应特征,达到多证据印证的特征学习与分类增强,是一种比较通用的表面缺陷实时检测解决方法。检测总体思想是从“已知的”无疵点纹理表面提取特征,根据特征对被测织物进行分类比较,从而检测出“未知的”疵点纹理区域。检测过程分为一次性时空域多特征证据自学习和在线分类检测两阶段。对实际织物图像序列的在线检测显示,对单色织物常见印染缺陷的有效检测速度达到了55帧/s(1 024×393像素分辨率仿真视频图像),动态检出正确率达到95%以上。     

Development of hydrogel patch for controlled release of alpha-hydroxy acid contained in tamarind fruit pulp extract

Synopsis The aim of this study was to develop hydrogel patch using crosslinked chitosan-starch as polymeric matrix for controlling the release of the natural alpha-hydroxy acid (AHA) contained in the extract of tamarind's fruit pulp. The chitosan (MW 100 000) was blended with corn, tapioca or rice starch in various ratios and then crosslinked with glutaraldehyde. The physical characteristics, mechanical resistance, bio-adhesion property and surface morphology of the prepared hydrogel patches with and without the extract were investigated. The release patterns of the hydrogel patches containing the extract were investigated by measuring the amount of tartaric acid, a major AHA present in the tamarind's fruit pulp extract, accumulated in the receptor medium of the vertical diffusion cell at various time intervals over a period of 6 h. The results indicated that the formulations of chitosan : corn starch 4.5 : 0.5 with glutaraldehyde 0.02% w/w (C(4.5)C(0.5)G(0.02)) or 0.04% w/w (C(4.5)C(0.5)G(0.04)), chitosan : tapioca starch 4.5 : 0.5 with glutaraldehyde 0.04% w/w (C(4.5)T(0.5)G(0.04)) or 0.05% w/w (C(4.5)T(0.5)G(0.05)), and chitosan : rice starch 4.5 : 0.5 with glutaraldehyde 0.04% w/w (C(4.5)R(0.5)G(0.04)) and chitosan : rice starch 4.0 : 1.0 with glutaraldehyde 0.03% w/w (C(4.0)R(1.0)G(0.03)) provided the flexible and elastic patches with good bio-adhesive property. The tensile strength values ranged from 5 to15 N mm(-2) and the elasticity ranged from 30 to 60%. The addition of the extract in these formulations significantly increased the tensile strength values of the obtained patches. The patch of C(4.0)R(1.0)G(0.03) formulation containing the extract showed relatively highest porosity, corresponding to its highest amount (12.02 +/- 0.33 mg) and rate (0.452 +/- 0.012 mg mm(-2) min(-1/2)) of tartaric acid released. The amounts of tartaric acid released from the developed hydrogel patches were proportional to a square root of time (Higuchi's model), particularly the release from C(4.0)R(1.0)G(0.03) (R(2), 0.9978 +/- 0.0020) and C(4.5)R(0.5)G(0.04) (R(2), 0.9961 +/- 0.0024) patches.     

Nitrogen and carbon dioxide adsorption by soils

High-resolution nitrogen (77 K) and carbon dioxide (273 K) adsorption at subatmospheric pressures has been studied for a range of model soils of various origins with different organic matter (OM) contents. It is demonstrated that N2 and CO2 molecules probe different regions of soil particles. Nitrogen is adsorbed primarily on the outer surface of soil particles, while CO2 has a higher affinity to OM domains. Low-pressure nitrogen adsorption reveals that soil particle surfaces consist of clay/mineral domains with discrete patches of OM. A linear correlation has been found between the CO2 uptake and the amount of organic carbon reduced per unit of the external surface area. A new method for discriminating the microporosity of soil particles and accessibility of OM has been proposed.     

An integrated method of 3D garment design

We present an intuitive method that seamlessly integrates the whole process of garment design including 3D modeling, pattern development, garment simulation, and grading. Firstly, a sketch-based modeling method is proposed to design a 3D garment using editable control curves. Secondly, 2D patterns are developed by flattening 3D surface patches, then a 3D fine garment is formed directly based on the information of sewing relations and correspondence between 3D surfaces and 2D patterns. Lastly, garment templates are introduced to realize automatic design-preserving transfer of garments between human bodies with different sizes and shapes. The method is able to design 3D garments and 2D patterns efficiently and accurately. Our study provides an easy-to-learn and easy-to-use tool for both fashion designers and computer artists.     

Pantone六色高保真印刷呈色特性研究

为了找出高保真六色印刷复制色彩传递的一般规律,通过一系列印前处理及色彩管理原理和技术,按照一定规律对六原色CMYKOG的双色、三色、四色按不同的网点面积率进行组合,通过对输出打样的测试版色块的测量,得到其色彩传递特性。实验结果表明:不同的网点叠印颜色组合对色调、明度、彩度的影响不同;黑色对色调的影响不明显,黑色的网点面积率在10%～70%时,对亮度和彩度影响显著;不同原色随着网点面积率的增加,其彩度变化不同;实地浅的原色,其实地彩度高于实地深的原色;随着原色网点面积率的不断增加,其彩度呈现对数增长,亮度几乎呈线性下降或者弱指数性下降。     

Surface hydrophobicity of commercial canola proteins mixed with κ-carrageenan or guar gum

The presence of hydrophobic patches on the protein surface can aid in its ability to adsorb at an oil–water or air–water interface. The surface hydrophobicity (S₀) of canola protein isolate (CPI)-hydrocolloid (κ-carrageenan, guar gum) systems was evaluated by fluorometric testing under varied conditions (NaCl, CPI and hydrocolloid concentrations; pH) using 8-Anilino-1-NaphthaleneSulphonate as a fluorescent probe. The S₀ values of CPI-hydrocolloid mixtures increased as hydrocolloid concentrations increased. High S₀ values reflect increased exposure of nonpolar amino acid residues due to changes in protein structure. This effect was greater at high pH and when guar gum was used.