检索结果-南通市图书馆

World Journal of Mechanics 2019年第6期9卷 163-176页

作者： Esteban Lopez Peter E. jenkins Mechanical Engineering Department University of Colorado Denver USA

This paper describes an experimental offside detection system that will be capable of detecting offside passes during a game of soccer. Soccer is the world’s most popular and most televised sport. In recent years, FIFA has implemented goal line technology in order to end controversial goals/missed goals during high profile competitive matches. The most contentious aspect of the sport is the offside rule and its many controversial calls or lack of calls. Sometimes the linesmen cannot see the passage of playing fast enough to make a correct decision. Being similar to goal line technology, people have requested offside technology to help the linesmen and to reduce the number of incorrect offside calls in a game. This paper describes a working offside detection system that can accurately detect offside passes. Positional data was exported from a VICON infrared motion tracking camera system and a MATLAB script was written so that it can analyze the positions of the players and the ball and determine if a pass was offside.

关键词： Soccer Motion Simulation

PoreScript:Semi-automated pore size algorithm for scaffold characterization

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Bioactive Materials 2022年第7期7卷 1-8页

作者： Dana jenkins Karim Salhadar grant Ashby Anita Mishra Joy Cheshire Felipe Beltran Melissa grunlan Sebastien Andrieux Cosima Stubenrauch Elizabeth Cosgriff-Hernandez Department of Biomedical Engineering University of Texas–AustinAustinTX78712USA Department of Biomedical Engineering Texas A&M UniversityCollege StationTX77843USA Universite de Strasbourg CNRSInstitut Charles Sadron UPR22F-67000StrasbourgFrance Institut für Physikalische Chemie Universitat StuttgartPfaffenwaldring 55D-70569StuttgartGermany

The scaffold pore size influences many critical physical aspects of tissue engineering,including tissue infiltration,biodegradation rate,and mechanical *** measurements of pore sizes from scanning electron micrographs using ImageJ/FIJI are commonly used to characterize scaffolds,but these methods are both time-consuming and subject to user *** semi-automated analysis tools are limited by a lack of accessibility or limited sample size in their verification *** work here describes the development of a new MATLAB algorithm,PoreScript,to address these *** algorithm was verified using three common scaffold fabrication methods(e.g.,salt leaching,gas foaming,emulsion templating)with varying pore sizes and shapes to demonstrate the versatility of this new *** results demonstrate that the pore size characterization using PoreScript is comparable to manual pore size *** PoreScript algorithm was further evaluated to determine the effect of user-input and image parameters(relative image magnification,pixel intensity threshold,and pore structure).Overall,this work validates the accuracy of the PoreScript algorithm across several fabrication methods and provides user-guidance for semi-automated image analysis and increased throughput of scaffold characterization.

关键词： Pore size measurement Polymer scaffolds MATLAB program Tissue engineering

Two decades of compositional and structural change in deciduous old-growth forests of Indiana,USA

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Plant Ecology 2016年第3期9卷 256-271页

作者： Christy A.Lowney Bradley D.graham Martin A.Spetich Stephen R.Shifley Michael R.Saunders Michael A.jenkins Department of Forestry and Natural Resources and Hardwood Tree Improvement and Regeneration Center Purdue University715 West State StreetWest Lafayette IN 47907USA Arkansas Forestry Sciences Laboratory USDA Forest ServiceSouthern Research StationP.O.Box 1270Hot SpringsAR 71902USA USDA Forest Service Northern Research Station202 ABNR BuildingColumbiaMO 65201USA

Aims Using a network of permanent plots,we determined how multiple old-growth forests changed over an 18-19-year period at a state-wide *** examination of change allowed us to assess how the compositional and structural stability of each forest varied with site characteristics(topography,physiography and productivity)and stochastic *** In 2011,we resampled 150 plots distributed across five old-growth hardwood forests in Indiana,USA that were originally sampled in *** each plot,we relocated and remeasured the diameter at breast height(dbh)of all trees(≥10.0 cm)present during the 1992-1993 sample,which allowed us to track their individual fates through time for growth and mortality *** that grew to≥10.0 cm dbh since plot establishment were designated as *** dbh and species of all saplings(stems≥2.0 cm butgs,density per ha was calculated by species for each *** also calculated annual mortality rate(AMR)for three diameter classes(10-29.9,30-59.9 and≥60 cm)and species richness(S),evenness(E)and Shannon-Weiner diversity(H')for the tree and sapling *** between years were compared for each forest using paired t-tests and Wilcoxon signed rank *** FindingsAlthough we observed commonality in changes across some sites,our results suggest that these forests differ in their rates and trajectories of *** in total stand BABA and density varied across sites and were influenced by past disturbance and mortality *** observed a general increase in the overstory dominance of Acer saccharum coupled with a general decrease in the dominance of Quercus section Lobatae(red oak group)*** of overstory trees present in 1992-1993 ranged from 27%to 49%over the study period(mean AM

关键词： forest remnants forest structure long-term data mortality species diversity stand development.

Simulink/MATLAB Model for Assessing the Use of a Centrifugal Pump as a Hydraulic Turbine

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Mechanics 2018年第7期8卷 253-271页

作者： Peter E. jenkins Artem Kuryachy Mechanical Engineering Department University of Colorado Denver USA

A centrifugal pump used as a hydraulic turbine in producing power for a microhydropower system is multifaceted. Centrifugal pumps are far more ubiquitous than turbines in the turbomachinery market, therefore being more readily available to the consumer. Additionally, they are cheaper. Hydraulic turbines undergo rigorous CFD simulation design and testing to establish their blade geometries and ranges of operation. This results in a refined but very expensive final product. Centrifugal pumps are thus presented as a logical alternative seeing that they can physically perform the same task as a hydropower turbine albeit at a reduced efficiency. This paper presents the results of an analysis and simulation to assess the use of a centrifugal pump as a hydraulic turbine.

关键词： Centrifugal Pump Hydraulic Turbine Simulink MATLAB Simulation

天语计划——寻找第二个太阳系及探索动态宇宙（英文）

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

天文学报 2024年第4期 3-45页

作者：冯发波芮易成杜芝茂林清张聪聪周丹崔开明 OgIHARA Masahiro 杨明林杰蔡永志杨涛只庞晓莹简明杰李文雄郭恒潇史弦史建春李荐扬郭康柔姚嵩陈啊明贾鹏谭先瑜 jenkins S.James 蒋宏轩张铭缘李可欣肖光耀郑书玥宣一帆郑捷何敏 JONES R.A.Hugh 宋翠英上海交通大学李政道研究所上海交通大学物理与天文学院上海天文馆(上海科技馆分馆) 中国科学院上海天文台同济大学测绘与地理信息学院中国科学院星系宇宙学重点实验室(中国科学技术大学) 中国科学技术大学天文与空间科学学院中国科学院云南天文台中国科学院天体结构与演化重点实验室国际超新星中心-云南省国际超新星研究重点实验室西安交通大学物理学院西交利物浦大学物理系上海师范大学上海市星系与宇宙学半解析研究重点实验室 Department of Astronomy Stockholm University 中国科学院国家天文台中山大学大气科学学院太原理工大学电子信息与光学工程学院 Instituto de Estudios Astrofísicos Facultad de Ingeniería y CienciasUniversidad Diego Portales Centro de Astrofísica y Tecnologías Afines(CATA) 山东大学空间与物理学院山东省光学天文与日地空间环境重点实验室中国科学院国家天文台中国科学院天文光学技术重点实验室 Centre for Astrophysics Research University of Hertfordshire 清华大学天体物理研究中心

像木星和土星这样的冷巨行星对类地行星的形成和宜居性起到了关键作用,因此,对像太阳系这样具有多个冷巨行星的系统的搜寻具有重要意义.Kepler以及TESS (Transiting Exoplanet Survey Satellite)太空望远镜成功地通过凌星的方法发现了... 详细信息

像木星和土星这样的冷巨行星对类地行星的形成和宜居性起到了关键作用,因此,对像太阳系这样具有多个冷巨行星的系统的搜寻具有重要意义.Kepler以及TESS (Transiting Exoplanet Survey Satellite)太空望远镜成功地通过凌星的方法发现了大量短周期行星,然而这些巡天项目的观测基线不足以发现更长周期的行星.为此,天语计划将部署两台1m望远镜(天语一号和天语二号),用于结合天语和其他计划的数据通过凌星法来发现冷巨行星及其他行星,并最终发现类太阳系.天语一号具有约10平方度的视场以及高速CMOS (complementary metal-oxide-semiconductor)科学相机,将对超过1000万颗恒星每小时进行一次高精度测光采样,并通过天语二号的多波段测光、光谱仪以及高分辨率成像对天语一号发现的候选行星进行确认.天语望远镜将放置于海拔约4000m的中国青海冷湖,是目前中国境内最好观测台址之一.天语对亮于14等星的测光精度为0.1%,对亮于18等星的测光精度优于1%,天语预计在5yr内将在类太阳周期发现超过300颗凌星行星,其中包括约17颗冷巨行星.基于系统轨道共面以及孪生地球发生率为10%的假设,天语预计将发现1-2个类太阳系,并可被未来的地球2.0计划所证实.此外,天语还将通过多种巡天观测模式测量从亚秒到周时标的光变,探测不同时标的时域现象,包括超新星早期光变、稀有变星和双星、潮汐瓦解事件、Be星、彗星活动以及系外小行星等.这些发现不仅将深化我们对宇宙的理解,还将为公众科学和科普提供重要平台.

关键词：技术:测光行星与卫星:探测行星与卫星:形成恒星:超新星:普通恒星:变星:普通小行星:普通恒星:伽马射线暴:普通

PROBLEMS IN THE MAINTENANCE OF A MATURE POWDER DIFFRACTION DATA BASE

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

PROBLEMS IN THE MAINTENANCE OF A MATURE POWDER DIFFRACTION D...

Computational Fluid Dynamics Analysis of Multi-Bladed Horizontal Axis Wind Turbine Rotor

Sixteenth Congress of the International Union of Crystallography

作者： R.jenkins International Centre for Diffraction Data SwarthmorePAU.S.A.

＜正＞The first issue of the Powder Diffraction File（PDF） dates back to the mid 1940’*** the intervening half a century mere has been a steady and ongoing effort on the part of the International Centre for Diffraction data（ICDD） to maintain and update the ***,new patterns are added to the file which today stands at about 60,000 entries.

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

World Journal of Mechanics 2020年第9期10卷 121-138页

作者： Nasim A. Mamaghani Peter E. jenkins Department of Mechanical Engineering University of Colorado Denver CO USA

The principal objective of this work was to investigate the 3D flow field around a multi-bladed horizontal axis wind turbine (HAWT) rotor and to investigate its performance characteristics. The aerodynamic performance of this novel rotor design was evaluated by means of a Computational Fluid Dynamics commercial package. The Reynolds Averaged Navier-Stokes (RANS) equations were selected to model the physics of the incompressible Newtonian fluid around the blades. The Shear Stress Transport (SST) k-ω turbulence model was chosen for the assessment of the 3D flow behavior as it had widely used in other HAWT studies. The pressure-based simulation was done on a model representing one-ninth of the rotor using a 40-degree periodicity in a single moving reference frame system. Analyzing the wake flow behavior over a wide range of wind speeds provided a clear vision of this novel rotor configuration. From the analysis, it was determined that the flow becomes accelerated in outer wake region downstream of the rotor and by placing a multi-bladed rotor with a larger diameter behind the forward rotor resulted in an acceleration of this wake flow which resulted in an increase the overall power output of the wind machine.

关键词： Computational Fluid Dynamics Horizontal Axis Wind Turbine Multi-Bladed Rotor Aerodynamic Torque

Leaching from Heterogeneous Heck Catalysts:A Computational Approach

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2002年第2期18卷 175-177页

作者： Peter. M. jenkins and Shik Chi Tsang Surface Science and Catalysis Research Centre, Department of Chemistry, University of Reading, Whiteknights, Reading, Rg6 6AD, UK Surface Science and Catalysis Research Centre Department of Chemistry University of Reading Whiteknights 英国 Reading

The possibility of carrying out a purely heterogeneous Heck reaction in practice without Pd leaching has been previously considered by a number of research groups but no general consent has yet arrived. Here, the reaction was, for the first time, evaluated by a simple computational approach. Modelling experiments were performed on one of the initial catalytic steps: phenyl halides attachment on Pd (111) to (100) and (111) to (111) ridges of a Pd crystal. Three surface structures of resulting were identified as possible reactive intermediates. Following potential energy minimisation calculations based on a universal force field, the relative stabilities of these surface species were then determined. Results showed the most stable species to be one in which a Pd ridge atom is removed from the Pd crystal structure, suggesting Pd leaching induced by phenyl halides is energetically favourable.

关键词： Heterogeneous Heck reaction, Aryl halides, Computational Modelling Leaching of palladium

Stand out.学生用书:大学英语实用听说教程

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论