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71.
NPP distribution related to the terrains along the North-South Transect of Eastern China 总被引:2,自引:0,他引:2
LI Yan LIAO Shendong CHI Guobin & LIAO Qifang . Spatial Information Research Center South China Normal University Guangzhou China . Guangdong Key Laboratory of RS GIS Applications Guangzhou China 《科学通报(英文版)》2004,49(6):617-624
Vegetation net primary productivity (NPP) is defined as the accumulative amount of organic matters per unit area and time, which is calculated from the difference between accumulative photosynthesis and accumulative autotrophic respiration by green plants. Since the NPP reflects the physiological and ecological characteristics of the plants and the interactive results of the environmental factors, it is an important index to evaluate a structure of ecological system, functional features and … 相似文献
72.
Nomenclature ki integral action coefficient[s-1]kp speed proportional gain[s-1]kv position proportional gain[s-1]kf feed forward factor of the speed loop[%]M axis mass[kg]V speed[m/s]F driving effort[N]Rc radius of curvature[m]d distance to the apex[m]o lateral offset[m]εcontouring error[m]ωm lowest mechanical resonant frequency[s-1]ζdamping coefficient[-]r inertia ratio[-]μmembership function[-]αcorner angle[rad]x,y horizontal and vertical coordinates[m]?angle to the normal line[rad]1.I… 相似文献
73.
Ibrahim M.AL-HARKAN 《系统科学与系统工程学报(英文版)》2005,14(2):187-206
1.Introduction Production sequencing and scheduling is one of the most important activities in production planning and control.Sequencing is defined as the order in which the jobs are processed through the machines.The allocation of machines over time to process a collection of jobs is defined as Scheduling.Several methods have been developed to solve the scheduling problem which can be classified as follows:1)efficient optimal methods,2)implicit and explicit,or complete enumerative methods,a… 相似文献
74.
"强纲领"是埃丁堡科学知识社会学学派(简称SSK)提出的研究知识社会成因的社会学形而上学理论.巴里·巴恩斯和大卫·布鲁尔是这个学派的理论家.他们把自己的纲领定位在"相对主义知识观"上,其批判的矛头直指科学哲学研究中的理性主义.在20世纪曾经占统治地位的科学哲学理性主义知识观受到挑战后,如何评价科学知识社会学的相对主义知识观?本文试图通过分析批判SSK相对主义知识观的几个主要观点,并对现代科学哲学中相关的理论做出历史反思和辩护来审视这个问题. 相似文献
75.
一代科学巨匠爱因斯坦,又是一位杰出的思想家,他的思想方法是耐人寻味的.他所创立的相对论,以其前提的简单、结构的新颖、体系的严谨、结论的正确,堪称现代物理理论之魁首.众所周知,相对论突破了经典力学的机械论囿限,否定了传统的绝对时空观念,披露了物质、运动、引力、时空的内在联系.相对论的建立,无疑是一个伟大的突破、一项卓越的创新.那么,爱因斯坦是如何突破和创新的呢?从方法论的角度,我们可从中吸取些怎么样的教益呢? 相似文献
76.
GanShi-xin 《武汉大学学报:自然科学英文版》2004,9(1):13-17
This paper investigates some conditions which imply the strong laws of large numbers for Banach space valued random variable sequences. Some generalizations of the Marcinkiewicz- Zygmund theorem and the HoffmannJφrgensen and Pisier theorem are obtained. 相似文献
77.
ZhangNing LiuHai-lin YuZhu-xing XiongRui ShiJing 《武汉大学学报:自然科学英文版》2004,9(1):55-58
The characteristics of electronic transport properties: behaviors of magnetization curve and magnetic relaxation of a typical normal superconductor 2H-NbSe2 are investigated. The results show that Tc and △Tc of the samples are 7. 2,0. 18 K, indicating that superconducting energy gap at zero temperature is 1. 1 meV. No fish tail shape is found in the magnetization curves at several temperatures. The relationship between remnant magnetic moment and time reveals that the magnetic flux creep of the sample agrees with the Kim-Anderson thermal activation model with the relaxation rate S=0.000 36 at T=6 K. 相似文献
78.
Xiao Ling Yu Zu-yu Yang Chao Zhu Hua-yue Du Yu-min College of Resource Environmental Science Wuhan University Wuhan Hubei China 《武汉大学学报:自然科学英文版》2004,9(2):247-251
0 IntroductionChitosanisadeacetylatedderivativeofchitin ,containinginitsstructure glucosamineandacetylglucosamine joinedthroughβ (1→ 4 )linkages.ItisinsolubleinwaterandcommonorganicsolventsbutsolubleatapHunder 6 .5acidicmedia.Duetoitsexcellentbiodegradableandbiocompatiblecharacter,chi tosanhasbeenexaminedextensivelyinthepharmaceuticalindus tryforitspotentialinthedevelopmentofdrugdeliverysys tems[1 ,2 ] .Gelatinisabiodegradablepolymerofwidesafety ,pro ducedfromcollagen ,themostabundantprote… 相似文献
79.
ZHAO Wei HU Ke KIMOTO Akitsu MIZUYAMA Takahisa . Institute of Environmental Science Beijing Normal University Beijing China . College of Earth Sciences Jilin University Changchun Jilin China . Laboratory of Erosion Control Graduate School of Agriculture Kyoto University Kyoto Japan 《武汉大学学报:自然科学英文版》2004,9(4):527-532
0 IntroductionManystudieshavebeendoneonthesedimentdischargeinMt.Tanakami .Thosestudiesconcerntheamountofsedi mentsandfewdiscussionsabouttheprocessonly .Andthesedi mentyieldmechanismindevastatedslopeinMt.Tanakamiisnotfullyunderstood.Inordertorecordthewholeprocessofsoilero sionfromthebeginningofprecipitation ,totheendofsedimentmovement,asimulatingexperimentbyusingartificialrainiscon ducted .Basedonthisexperiment,andbyfurthercomparingwiththepreviousdataofsedimentsinthisarea,somebasicdataaboutc… 相似文献
80.
MAOCheng-ying LUYan-sheng 《武汉大学学报:自然科学英文版》2004,9(5):687-693
As the increasing popularity and complexity of Web applications and the emergence of their new characteristics. the testing and maintenance of large, complex Web applications are becoming more complex and difficult. Web applications generally contain lots of pages and are used by enormous users. Statistical testing is an effective way of ensuring their quality. Web usage can be accurately described by Markov chain which has been proved to be an ideal model for software statistical testing. The results of unit testing can b eutilized in the latter stages, wbich is an important strategy for bottom-to-top integration testing, and the other improvement of extended Markov chain model (FMM) is to present the error type vector which is treated as a part of page node. This paper also proposes the algorithm for generating test cases of usage paths. Finally, optional usage reliability evaluation methods and an incremental usability regression testing model for testing and evaluation are presented. 相似文献