检索结果-南通市图书馆

Certainties and uncertainties of land cover statistics in China

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

Journal of Environmental Sciences 2003年第4期15卷 520-524页

作者： ZHAOJing-zhu SUNYi BAIGuang-xin WUGang SHAOGuo-fan ResearchCenterforEco-EnvironmentalSciences ChineseAcademyofSciencesBeijing100085China DepartmentofForestryandNaturalResources 1159ForestryBuildingPurdueUniversityWestLafayetteIN47907USA.

Vegetation or land cover maps have been made directly or indirectly available for the entire territory of China. The certainties and uncertainties of land cover statistics were analyzed by comparing three data sources: China's Vegetation Map, IGPB DISCover, and University of Maryland Product. Great similarities in the statistics of 7 aggregated land cover types were found among the three data sources, particularly between the two global land cover maps. The per pixel agreement between any 2 of 3 maps was between 38.0%—51.4%; the per pixel agreement among all three maps was only 27.1%. Certainties were found in regions where vegetation types are typical and human land use practice is relatively homogenous; the uncertainties occurred to either vegetation transition zones or regions where land cover types and land use practice are relatively diversified. Systematic and multidisciplinary efforts are necessary to promote accurate mapping of nationwide land cover types in China. Intensive efforts should be made in regions where uncertainties of land cover information are found.

关键词： uncertainties of land cover remote sensing spatial pattern landscape characterization

Turbulent flame image classification using Convolutional Neural Networks

在线全文

学校读者我要写书评

暂无评论

Energy and AI 2022年第4期10卷 87-94页

作者： Rathziel Roncancio Aly El Gamal Jay P.Gore School of Mechanical Engineering Purdue UniversityWest LafayetteIN47907USA School of Electrical and Computer Engineering Purdue UniversityWest LafayetteIN 47907USA

Pockets of unburned material in turbulent premixed flames burning CHs,air,and CO_(2) were studied using OH Planar Laser-Induced Fuorescence(PLIF)images to improve current *** flames are ubiquitous in most natural gas air combustors running gas turbines with dry exhaust gas recirculation(EGR)for land-based power *** improvements continue in the charactenization and understanding of turbulent flames with EGR particularly for transient events like ignition and *** and/or islands of unburned material within bumed and unburned turbulent media are some of the features of these *** features reduce the heat release rates and increase the carbon monoxide and hydrocarbons *** present work involves Convolutional Neural Networks(CNN)based dassification of PIF images containing unburned pockets in three turbulent flames with 0%,5%,and 10%CO_(2).The CNN model was constructed using three convolutional layers and two fully connected layers using dropout and weight *** of 94.2%,92.3%and 89.2%were registered for the three flames,*** present approach represents significant computational time savings with respect to conventional image processing methods.

关键词： CNN Flame Neural network Turbulent

A numerical study of two-and three-dimensional detonation dynamics of pulse detonation engine by the CE/SE method

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

Acta Mechanica Sinica 2005年第1期21卷 32-39页

作者： ChunshengWeng JayP.Gore SchoolofPowerEngineering NanjingUniversityofScience&TechnologyNanjing210094China SchoolofPowerEngineering NanjingUniversityofScience&TechnologyNanjing210094China//SchoolofMechanicalEngineenngPurdueUniversityIN47907USA

In this paper, the CE/SE method is developed to simulate the two- and three-dimensional flow-field of Pulse Detonation Engine (PDE). The conservation equations with stiff source terms for chemical reaction are solved in two steps. The detailed analysis of computational results of a PDE with a single detonation tube and a PDE with five detonation tubes are given in this paper. Complex wave systems are observed inside and outside a PDE. For a PDE with 5 detonation tubes, there is a big bow shock produced from a number of little shocks near the open ends of tubes. A lot of vortexes interact with shocks and a large expansion wave propagates forward and backward with respect to the PDE in a semi-oval shape.

关键词： pulse detonation engine detonation shock numerical simulation CE/SE method

SOLVXBILITY　OF　FORWARD－BACKWARD　SDES　AND　THE　NODAL　SET　OF　HAMILTON－JACOBI－BELLMAN　EQUATIONS

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 1995年第3期16卷 279-298页

作者： MAJIN YONGJIONGMIN DepartmentofMathematics PurdueUniversityWestLafayetteIN47907 DepartmentofMathematics FudanUniversityShanghai200433China

The solvability of a class of forward-backward stochastic differential differential equations(SDEs for short)over an arbitrarily prescribed time duration is studied. The authors design a stochastic relaxed control problem, with both drift and diffusion all being controlled, so that the solvability problem is converted to a problem of finding the nodal set of the viscosity solution to a certain Hamilton-Jacobi-Bellman *** method overcomes the fatal difficulty encountered in the traditional contraction mapping approach to the existence theorem of such SDEs.

关键词： Forward-backward stochastic differential equations Stochastic control Relaxed control Viscosity solutions Nodal set.

Minimizing liver uptake of cationic ^(99m)Tc radiotracers with ether and crown ether functional groups

在线全文

学校读者我要写书评

暂无评论

World Journal of Hepatology 2010年第1期2卷 21-31页

作者： Young-Seung Kim School of Health Sciences Purdue University550 Stadium Mall DriveWest LafayetteIN47907United States

Ischemia-related diseases,particularly coronary artery disease(CAD),account for the majority of deaths *** ischemia is a serious condition and the delay in reperfusion of ischemic tissues can be *** is particular true in the aged *** and accurate early detection of myocardial ischemia is highly desirable so that various therapeutic regiments can be given before irreversible myocardial damage *** perfusion imaging with radiotracers is an integral component in evaluations of patients with known or suspected CAD. 99m Tc-Sestamibi and 99m Tc-Tetrofosmin are commercial radiopharmaceuticals currently available for myocardial perfusion *** their widespread clinical applications,both 99m Tc-Sestamibi and 99m Tc-Tetrofosmin do not meet the requirements of an ideal perfusion imaging agent,largely due to their high liver *** intense liver uptake makes it difficultto interpret the heart activity in the inferior and left ventricular *** scattering from the high liver radioactivity accumulation remains a significant challenge for diagnosis of heart *** review will summarize the most recent research efforts to minimize the liver uptake of cationic 99m Tc radiotracers by using ether and crown ether-containing chelators. Fast liver clearance will shorten the duration of imaging protocols(<30 min post-injection) ,and allow for early acquisition of heart images with high quality. Improvement of heart/liver ratio may permit better detection of the presence and extent of coronary artery *** of such a new radiotracer that allows for the improved noninvasive assessment of myocardial perfusion would be of considerable benefit in treatment of patients with suspected CAD.

关键词： Myocardial perfusion imaging Cationic 99mTc radiotracers Single photon emission computed tomography

A three-stage method with efficient calculation for lot streaming flow-shop scheduling

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

Frontiers of Information Technology & Electronic Engineering 2019年第7期20卷 1002-1021页

作者： Hai-yan WANG Fu ZHAO Hui-min GAO John WSUTHERLAND College of Mechanical and Electrical Engineering Jiaxing UniversityJiaxing314000China Environmental and Ecological Engineering Purdue UniversityWest LafayetteIN47907USA School of Mechanical Engineering Purdue UniversityWest LafayetteIN47907USA

An important production planning problem is how to best schedule jobs(or lots)when each job consists of a large number of identical *** problem is often approached by breaking each job/lot into sublots(termed lot streaming).When the total number of transfer sublots in lot streaming is large,the computational effort to calculate job completion time can be ***,researchers have largely neglected this computation time *** provide a practical method for production scheduling for this situation,we propose a method to address the n-job,m-machine,and lot streaming flow-shop scheduling *** consider the variable sublot sizes,setup time,and the possibility that transfer sublot sizes may be bounded because of capacity constrained transportation *** proposed method has three stages:initial lot splitting,job sequencing optimization with efficient calculation of the makespan/total flow time criterion,and transfer *** experiments are conducted to confirm the effectiveness of the three-stage *** experiments reveal that relative to results reported on lot streaming problems for five standard datasets,the proposed method saves substantial computation time and provides better solutions,especially for large-size problems.

关键词： Lot streaming Flow-shop scheduling Transfer sublots Variable size Bounded size Differential evolution

Sonolytic degradation of 2-chlorobiphenyl

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University of Technology 2004年第3期11卷 309-311页

作者：张光明华天星常爱敏 School of Shenzhen Graduate Tsinghua University Shenzhen 518057China School of Civil Engineering Purdue University Indiana IN47907-1084 USA Shenzhen Water Quality Monitoring Station Shenzhen 518001 China

The sonolytic degradation of 2-chlorobiphenyl was investigated. Mass spectroscopy was used to detect the products of sonolytic degradation of 2-chlorobiphenyl. The results show that the products of sonolytic degradation, such as biphenyl, ethyl benzene, diethylbiphenyl, dibutylbiphenyl, phenol, propylphenol and di-tert-butyl phenol are produced by thermolysis and hydroxyl free radical reactions, in which biphenyl counts for almost 40%（mole fraction） of the mother compound and others are at trace level. Rapid accumulation of chloride ion shows quick dechlorination, and 78% organic chlorine is converted into chloride ion. Free radical scavengers, bicarbonate and carbonate, decrease the reaction rate of sonolytic degradation of 2-chlorobiphenyl significantly, and the pseudo 1st order rate constant of sonolytic degradation of 2-chlorobiphenyl decreases linearly with the natural logarithm of the concentration of the added free radical scavenger, showing that the pyrolysis and hydroxyl free radical reaction are the two major pathways for the sonolytic degradation of 2-chlorobiphenyl, in which the hydroxyl radical concentration is estimated to be 1×10-10 （mol/L.）

关键词： sonolytic degradation 2-chlorobiphenyl pyrolysis hydroxyl free radical

在线全文

学校读者我要写书评

暂无评论

星载激光测高技术进展

测绘学报 2022年第6期51卷 964-982页

作者：单杰田祥希李爽李韧菲普渡大学土木工程学院西拉法叶IN47907美国

星载激光(雷达)测高技术已经逐步成为全方位全球观测的技术手段之一,其高测量精度、全天时测量能力、高效三维测量的特点在许多科学领域都具有独特的优势。本文讨论当前两类星载激光测高技术的工作原理、数据处理方法,并探讨了星载激光... 详细信息

星载激光(雷达)测高技术已经逐步成为全方位全球观测的技术手段之一,其高测量精度、全天时测量能力、高效三维测量的特点在许多科学领域都具有独特的优势。本文讨论当前两类星载激光测高技术的工作原理、数据处理方法,并探讨了星载激光测高数据在对地观测和深空观测科学研究中的代表性应用;最后展望了未来星载激光测高技术的发展趋势。期望本文对从事星载激光测高研究、开发和应用的同行们有所裨益。

关键词：星载激光测高地形测绘林业生态测绘极地海洋测绘行星测绘线性激光雷达光子计数激光雷达

Urban Three-dimensional Expansion and Its Driving Forces——A Case Study of Shanghai,China

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2009年第4期19卷 291-298页

作者： SHI Longyu SHAO Guofan CUI Shenghui LI Xuanqi LIN Tao YIN Kai ZHAO Jingzhu Institute of Urban Environment Chinese Academy of Sciences Xiamen 361003 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Department of Forestry and Natural Resources Purdue University West Lafayette IN47907 USA

Urban expansion is a phenomenon of urban space increase,and an important measuring index of the process of *** Shanghai as an example,the changes of urban average height and built-up area were studied to represent city's vertical and horizontal increases respectively,and statistical methods were used to analyze the driving forces of urban *** research drew following conclusions:1) The urban expansion process of Shanghai from 1985 to 2006 had a clear periodic feature,and could be divided into three stages:vertical expansion in dominance,coordinated vertical and horizontal expansion,and horizontal expansion in dominance.2) The average height and quantity of buildings in core city were significantly bigger than those in suburbs,but the changing speed of the latter was *** 3) urbanization process was the major driving force for the city's horizontal expansion,while industrial structure improvement was the key driving factor for the vertical *** two driving forces were simultaneously affected by city's political factors.

关键词： urban expansion three-dimensional space urbanization urban vertical expansion urban horizontal ex-pansion Shanghai China