检索结果-南通市图书馆

中国宝玉石 2007年第1期 117-117页

polygon是珠宝业最大、最活跃的网上B2B交易市场,致力于向珠宝业人士提供专业服务。

关键词： polygon

Vibration induced flow in hoppers:DEM 2D polygon model

在线全文

学校读者我要写书评

暂无评论

Particuology 2008年第6期6卷 455-466页

作者： Feras Y. Fraige Paul A. Langston Andrew J. Matchett John Dodds Faculty of Mining and Environmental Engineering Al-Hussein Bin Talal University Jordan Chemical and Environmental Engineering Nottingham University University Park Chemical Engineering University of Teesside Centre RAPSODEE Ecole Des Mines

A two-dimensional discrete element model （DEM） simulation of cohesive polygonal particles has been developed to assess the benefit of point source vibration to induce flow in wedge-shaped hoppers. The particle-particle interaction model used is based on a multi-contact principle. The first part of the study investigated particle discharge under gravity without vibration to determine the critical orifice size （Bc） to just sustain flow as a function of particle shape. It is shown that polygonal-shaped particles need a larger orifice than circular particles. It is also shown that Bc decreases as the number of particle vertices increases. Addition of circular particles promotes flow of polygons in a linear manner. The second part of the study showed that vibration could enhance flow, effectively reducing Bc. The model demonstrated the importance of vibrator location （height）, consistent with previous continuum model results, and vibration amplitude in enhancing flow.

关键词： Bulk solids Vibration DEM Hoppers Materials handling polygon

A Fast Algorithm for polygon Operations

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 1991年第1期6卷 91-96页

作者：蔡士杰张福炎 Department of Computer Science Nanjing UniversityNanjing 210008

In this paper,a fast algorithm for polygon operations is *** intersection validation testingmethod is described.

关键词： intersection polygon operations hidden vertex straight bounding sorting outside instead

Study on polygon Region Filling Method

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2000年第2期12卷 104-106页

作者： WANG Jia-yang CHEN Song-qiao WANG Can-dong College of Information Science and Engineering Central South University of TechnologyChangsha 410083China

The paper puts forward a highly efficient and practical scan line based on the filling algorithm. The algorithm takes the lines of polygon as line segments with directions and introduces the concept of marked value when the apex of polygon faces scan line, determines whether there are intersection points between the lines of polygon and scan lines, by judging whether the marked value has changed or not. This method avoids the extra decision and treatment of odd points in traditional algorithm, and it needs little calculations but it is highly efficient.

关键词： computer graphics filling algorithm polygon

High-speed rendering pipeline for polygon-based holograms

在线全文

学校读者我要写书评

暂无评论

Photonics Research 2023年第2期11卷 313-328页

作者： FAN WANG TOMOYOSHI ITO TOMOYOSHI SHIMOBABA Graduate School of Engineering Chiba UniversityChiba 263-8522Japan

As an important three-dimensional(3D) display technology, computer-generated holograms(CGHs) have been facing challenges of computational efficiency and realism. The polygon-based method, as the mainstream CGH algorithm, has been widely studied and improved over the past 20 years. However, few comprehensive and high-speed methods have been proposed. In this study, we propose an analytical spectrum method based on the principle of spectral energy concentration, which can achieve a speedup of nearly 30 times and generate highresolution(8K) holograms with low memory requirements. Based on the Phong illumination model and the subtriangles method, we propose a shading rendering algorithm to achieve a very smooth and realistic reconstruction with only a small increase in computational effort. Benefiting from the idea of triangular subdivision and octree structures, the proposed original occlusion culling scheme can closely crop the overlapping areas with almost no additional overhead, thus rendering a 3D parallax sense. With this, we built a comprehensive high-speed rendering pipeline of polygon-based holograms capable of computing any complex 3D object. Numerical and optical reconstructions confirmed the generalizability of the pipeline.

关键词： rendering polygon computer

Ultrawide-band optically transparent antidiffraction metamaterial absorber with a Thiessen-polygon metal-mesh shielding layer

在线全文

学校读者我要写书评

暂无评论

光子学研究:英文版 2023年第7期11卷 1354-1363页

作者： NAITAO SONG QIAO SUN SU XU DONGZHI SHAN YANG TANG XIAOXI TIAN NIANXI XU JINGSONG GAO Key Laboratory of Optical System Advanced Manufacturing Technology Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China State Key Laboratory of Applied Optics Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China College of Da Heng University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China Jilin Provincial Key Laboratory of Advanced Optoelectronic Equipment and Instrument Manufacturing Technology Changchun 130033China

Transparent absorbers, with a functional integration of broadband electromagnetic shielding, microwave camouflage,and optical transparency, have attracted increasing attention in the past decades. Metal mesh, an artificial, optically transparent, conducting material composed of periodic metallic gratings, is the optimal choice for the microwave shielding layer of transparent absorbers because of its excellent compatibility between high transparency and low resistance. However, the micrometer-level periodicity of metallic grating concentrates the diffraction of light, which degrades the imaging quality of cameras and sensors in common. In this study, we report on a generalized Thiessenpolygon-randomization method that prevents the concentration of the diffraction of light in periodic metallic grating and demonstrate an ultrawide-band optically transparent diffraction-immune metamaterial absorber. The absorber is constructed with a multilayer indium-tin-oxide-based metasurface and a Thiessen-polygon-randomized metal-mesh reflector. The lossy metasurface provides multimode absorption, whereas the Thiessen-polygon randomization prevents the concentration of the diffraction of light. The practical sample achieves a 10 dB absorptivity and shielding effectiveness over a range of 8–26.5 GHz, and the optical transparency is also preserved over the entire visible and near-infrared regions. The point spread function and field of view are both improved by using the antidiffraction absorber. Our study paves the way for the application of optically transparent electromagnetic devices, display, and optoelectronic integration in a more practical stage. ? 2023 Chinese Laser Press.

关键词： absorber transparent polygon

CALCULATION OF CHARACTERISTIC IMPEDANCES OF TRANSMISSION LINE WITH COUPLED REGULAR polygon BARS BETWEEN PARALLEL PLATES

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1984年第7期29卷 877-882页

作者：曾令儒 Beijing Institute of Tracking Telemetry and Control

In previous papers, we presented a method to solve the characteristic impedances of five new transmission lines and thirteen existing lines. In this paper, in order to check the accuracy of the method in Ref. [1], a new method is adopted to deal with the transmission line with coupled square bars between parallel plates, and it is proved that the characteristic impedances of coupled regular polygon bars between parallel plates can be derived directly by converting the formulae or calculating the values of the characteristic impedances of coupled rods between ground planes.

关键词： polygon calculating formulae converting transformed illustrated latter hexagonal bounds tables

No Fit polygon for Nesting Problem Solving with Hybridizing Ant Algorithms

在线全文

学校读者我要写书评

暂无评论

Journal of Software Engineering and Applications 2014年第5期7卷 433-439页

作者： Qiang Yang Computer School Yangtze University Jingzhou China

In design science, these two kinds of problems are mutually nested, however, the nesting could not blind us for the fact that their problem-solving and solution justification methods are different. The ant algorithms research field, builds on the idea that the study of the behavior of ant colonies or other social insects is interesting, because it provides models of distributed organization which could be utilized as a source of inspiration for the design of optimization and distributed control algorithms. In this paper, a relatively new type of hybridizing ant search algorithm is developed, and the results are compared against other algorithms. The intelligence of this heuristic approach is not portrayed by individual ants, but rather is expressed by the colony as a whole inspired by labor division and brood sorting. This solution obtained by this method will be evaluated against the one obtained by other traditional heuristics.

关键词： Genetic Algorithm Search Ant Algorithms No Fit polygon Simulated Annealing

The Rate of Asymptotic Normality of Frequency polygon Density Estimation for Spatial Random Fields

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Statistics 2018年第6期8卷 962-973页

作者： Shanchao Yang Xin Yang Guodong Xing Yongming Li School of Mathematics and Statistics Guangxi Normal University Guilin China Department of Mathematics Guilin University of Aerospace Technology Guilin China School of Mathematical Sciences Xiamen University Xiamen China School of Mathematics Shangrao Normal University Shangrao China

This paper is to investigate the convergence rate of asymptotic normality of frequency polygon estimation for density function under mixing random fields, which include strongly mixing condition and some weaker mixing conditions. A Berry-Esseen bound of frequency polygon is established and the convergence rates of asymptotic normality are derived. In particularly, for the optimal bin width , it is showed that the convergence rate of asymptotic normality reaches to ?when mixing coefficient tends to zero exponentially fast.

关键词： Frequency polygon Berry-Esseen Bound Rate of Asymptotic Normality Mixing Random Field

A Gradient Search Algorithm for the Maximal Visible Area polygon Problem

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Operations Research 2015年第3期5卷 168-178页

作者： Helman I. Stern Moshe Zofi Department of Industrial Engineering and Management Ben-Gurion University of the Negev Beersheva Israel Department of Industrial Management Sapir College Sderot Israel

This paper provides a gradient search algorithm for finding the maximal visible area polygon (VAP) viewed by an interior point in a simple polygon P. The algorithm is based on a natural partition of P into convex sets, such that each element of the partition is associated with a unique analytical form of the area function. We call this partition a back diagonal partition of P. Our maximal VAP algorithm converges in a finite number of steps, and is polynomial with a complexity of , for a simple polygon P with n vertices, and r reflex vertices. We use the maximal VAP algorithm as a basis for a greedy heuristic for the well known guardhouse problem with a computation complexity of .

关键词： Maximal Visible polygon Gradient Search Continuous Optimization Guardhouse Problem