3D fingerprint reconstruction system using feature correspondences and prior estimated finger model

The paper studies a 3D fingerprint reconstruction technique based on multi-view touchless fingerprint images. This technique offers a solution for 3D fingerprint image generation and application when only multi-view 2D images are available. However, the difficulties and stresses of 3D fingerprint reconstruction are the establishment of feature correspondences based on 2D touchless fingerprint images and the estimation of the finger shape model. In this paper, several popular used features, such as scale invariant feature transformation (SIFT) feature, ridge feature and minutiae, are employed for correspondences establishment. To extract these fingerprint features accurately, an improved fingerprint enhancement method has been proposed by polishing orientation and ridge frequency maps according to the characteristics of 2D touchless fingerprint images. Therefore, correspondences can be established by adopting hierarchical fingerprint matching approaches. Through an analysis of 440 3D point cloud finger data (220 fingers, 2 pictures each) collected by a 3D scanning technique, i.e., the structured light illumination (SLI) method, the finger shape model is estimated. It is found that the binary quadratic function is more suitable for the finger shape model than the other mixed model tested in this paper. In our experiments, the reconstruction accuracy is illustrated by constructing a cylinder. Furthermore, results obtained from different fingerprint feature correspondences are analyzed and compared to show which features are more suitable for 3D fingerprint images generation.     

用两个形状指数表征粉煤灰颗粒形貌的研究

引用两个形状指数表征颗粒形状的概念,即先将颗粒形状近似为椭圆,再将椭圆图像分离:以圆为基准的颗粒宏观形状指数δ;以光滑椭圆为基准的颗粒轮廓凹凸度,即微观形状指数ζ。分析和发展了近似椭圆模型。并运用图像分析仪对粉煤灰、水泥样品进行实验。结果表明,粉煤灰颗粒的两个形状指数δ和ζ都大于水泥颗粒。证明粉煤灰颗粒的球形度、表面光滑度优于水泥,而且,随着粒径增大,δ和ζ呈下降趋势,表明磨制颗粒越粗。(?)粒形状越不规则。文中还运用近似椭圆模型再现了颗粒的模拟图像。     

Exploration of mesoporous structure of tunisian raw and acid-leached phosphate ore particles

Rock phosphate fractions were examined for their porous structure by nitrogen adsorption. The pore size distribution and the shape of pores does not seem to depend on the particle size. The specific surface area values present two regions, one above and one below that of the particles with 125 μrn diameter. Particles of a given size were leached with dilute phosphoric acid (1.5 mass% P₂O₅) at 25°C. It was observed that there is a widening of the initial pores during leaching. The particles collected at the initial period of the reaction are pitted and those collected at the final period are disintegrated.     

淡远深邃,天蓝海碧——浅析《天空之城》色彩环境塑造的艺术

色彩之于影视动画,是视觉元素中非常重要的一环,它在塑造环境、烘托主题、助推情节发展以及奠定电影整体感情基调中发挥着不可替代的作用。宫崎骏的动画电影《天空之城》之色彩环境塑造水平,体现了导演深厚的色彩造型功力,文章试从人物色彩造型、故事情节渲染和音乐色彩表现等方面分析电影《天空之城》色彩环境塑造的艺术。     

乙醇和二甲醚微射流火焰燃烧特性研究

采用实验及数值计算研究了乙醇和二甲醚微圆管射流火焰燃烧特性。通过实验观察到不同燃料流速下乙醇和二甲醚火焰都具有四种典型的火焰形态；使用平面激光诱导荧光测试系统获得了微射流火焰的OH基元分布，实验结果表明在较高流速下稳定燃烧的乙醇火焰比二甲醚火焰直径小，且略高于二甲醚火焰；采用考虑详细化学反应机理的数值计算对乙醇和二甲醚火焰进行了数值模拟，计算结果与实验现象吻合较好；利用一维非预混对冲火焰计算进一步研究了这两种燃料的化学反应路径，分析结果表明乙醇和二甲醚火焰的中间产物有显著差异，两种燃料化学反应特性的差异导致了不同的微火焰结构。     

热塑性弹性体SBS异型材挤出模具设计

本文通过对异型材截面形状及原材料挤出成型性能分析，设计了正确的口模形状及合理的流线形流道，设计的模具能够生产出符合尺寸精度要求的型材。     

Thermoporometry as a new tool in analyzing mesoporous MCM-41 materials

Thermoporometry, a calorimetric procedure, is applied for measuring the pore size distribution, pore volume and surface area of mesoporous MCM-41 molecular sieves using water as the adsorbate. A series of MCM-41 materials with various pore diameters was synthesized and subjected to the new method. The results are compared with nitrogen physisorption. Both methods are complementary, whereby the former provides also information about the pore shape. MCM-41 materials with pores wider than 50 Å also allow the use of benzene as the adsorbate in thermoporometry.     

牙舟泥哨

牙舟泥哨作为民间陶制玩具在数百年的发展中逐渐形成了自己的风格和个性，在造型、审美上带有独特黔南地方特色。本文从造型和审美的角度对牙舟泥哨进行了分析。     

Atomization of metal fluorides for enhanced flow characteristics of a multicomponent powder

The National Aeronautics and Space Administration's (NASA's) PS304 coating is a plasma spray deposited tribological coating with feedstock composed of NiCr, Cr₂O₃, Ag and BaF₂-CaF₂ powders. The effects of rounded BaF₂-CaF₂ particles on the gravity-fed flow characteristics of PS304 feedstock have been investigated. The BaF₂-CaF₂ powder was fabricated by water atomization using four sets of process parameters. Each of these powders was then characterized by microscopy and classified by screening to obtain 45-106 μm particles and added incrementally from 0-10 wt.% to the other constituents of the PS304 feedstock, namely nichrome, chromia and silver powders. The relationship between feedstock flow rate, measured with the Hall flowmeter, and concentration of fluorides was found to be linear in each case. The slopes of the lines were between those of the linear relationships previously reported using angular and spherical fluorides and were closer to the relationship predicted using the rule of mixtures. The results offer a fluoride fabrication technique potentially more cost-effective than gas atomization processes or traditional comminution processes.     

基于聚类人体体型分类法的体型反算方法研究

用聚类法将大量人体样本尺寸数据进行体型分类。是目前较先进的一种人体体型分类方法．但分类后若根据个体尺寸数据反向判断其所属的聚类体型则较为困难．本文经过多个设计方案,对实际测量的人体数据进行分析计算和对比,得出一种效果好、计算量小的实用反向判断方法．