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基于条件异方差分析的水文时序模型及其应用

系统工程理论与实践 2009年第11期29卷 19-30页

作者：王红瑞高雄常晋源左恒北京师范大学水科学研究院-水沙科学教育部重点实验室北京100875 北京师范大学数学科学学院北京100875

针对条件异方差现象在水文过程的时序研究中常被忽略的情况,建立了水文过程时间序列分析和预测模型.首先,利用Census X12分解水文时序,由其得到的周期项与趋势项分别建立相应的条件异方差模型;其次,对于分解序列后得到的残差项,建立基... 详细信息

针对条件异方差现象在水文过程的时序研究中常被忽略的情况,建立了水文过程时间序列分析和预测模型.首先,利用Census X12分解水文时序,由其得到的周期项与趋势项分别建立相应的条件异方差模型;其次,对于分解序列后得到的残差项,建立基于BX数据生成的灰色Markov预测模型;再次,将三个模型进行耦合,编制了算法流程,由此提出了一种基于条件异方差的水文时序分析与预测模型;最后以河南省淮河流域的鲇鱼山水文站1975-1999年逐月的径流量为例进行了应用验证.研究结果表明:提出的模型从预测效果来看,总的平均偏差只有17.42%,其精度要明显高于常规的水文时序分析中ARCH和ARMA(1,1)等传统方法.

关键词：时间序列分解条件异方差模型灰色BX数据生成法灰色Markov预测模型鲇鱼山水文站

Solution of stress intensity factors of multiple cracks in plane elasticity with eigen COD formulation of boundary integral equation

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Journal of Shanghai university(English Edition) 2011年第3期15卷 173-179页

作者：郭钊马杭 Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Department of Mechanics College of Sciences Shanghai University

The concept of eigen crack opening displacement （COD） can be defined as the COD of a crack in infinite plate under the tractions acting on the crack surface. By introducing this concept, the eigen COD formulation of boundary integral equation is proposed in this paper, together with the solution procedures for multiple crack problems in plane elasticity. With the proposed approach, the multiple crack problems can be solved with the conventional displacement discontinuity boundary integral equations in an iterative fashion with a small size of system matrix as that in the numerical Green’s function （NGF） approach but without the trouble to determine the complementary solutions since the standard boundary element discretization on the crack surface is no longer required with the proposed approach. Some numerical examples computing the stress intensity factors are presented and compared with those in literature to show the accuracy and the effectiveness of the proposed approach.

关键词： crack opening displacement (COD) multiple cracks stress intensity factor boundary integral equation iteration

Study on the spatial differences and its time lag effect on climatic factors of the vegetation in the Longitudinal Range-Gorge Region

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Science Bulletin 2007年第S2期 42-49页

作者： BAO YaJing~1 SONG GuoBao~(1,2) LI ZhengHai~(1,3) GAO JiXi~3 L HaiYan~4 WANG HaiMei~5 CHENG Yan~6 XU Tian~7 1 Institute of Bio-Resources and Environment,college of Life Science,Dalian Nationalities university,Dalian 116600,china 2 college of Resources Science and Technology,Beijing Normal university,Beijing 100875,china 3 Innovation Base of Regional Ecology,Chinese Research Academy of Environmental sciences,Beijing 100012,china 4 Institute of Agricultural Resources and Regional Planning,Chinese Academy of Agricultural sciences,Beijing 100081,china 5 Inner Mongolia Municipality Observatory,Huhhot 010051,china 6 college of Ecological Environment,Inner Mongolia Agricultural university,Huhhot 010018,china 7 college of Life Science,Inner Mongolia university,Huhhot 010021,china

This article analyzes the correlation of NDVI and two meteorological data including temperature and precipitation,and probes the spetial pattern of responding sensitivity of the vegetation to temperature and precipitation *** constructing the NDVIrindex,the relation between vegetation cover and land use in the Longitudinal Range-Gorge Region（LRGR）is *** conclusion is as follows:（1） The time lag effect that vegetation responds to temperature and precipitation change is ***- ferent regions have different delay time corresponding to maximum correlation *** to response time of precipitation and temperature combination,three kinds of temperature-precipi- tation forms are defined,namely,precipitation and temperature in the same time,precipitation prior to temperature and temperature prior to precipitation.（2）The spatial distribution of sensitivity,of which vegetation responses to temperature,is characterized by several high and low scattered correlation *** from temperature,two insensitive regions and two sensitive belts are formed to pre- sent the response of vegetation to precipitation.（3）The NDVIris constructed,which can perfectly re- flect the corresponding relationship between meteorological factors and land use condition in the LRGR.

关键词： land cover meteorological factors effect of time lag spatial correlation population density Longitudinal Range-Gorge Region(LRGR)

ACCELERATING RAY TRACING THROUGH POLYGON PROJECTION

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Computer Aided Drafting,Design and Manufacturing 1996年第2期6卷 43-49页

作者： Jin Xiaogang Wan Huagen Peng Qunsheng(State Key Laboratory of CAD and CG Department of Applied Mathematics) zhejiang university hangzhou,zhejiang Province,310027P.R.china

An algorithm for accelerating ray tracing through polygon projection is *** tracing,as it is well known,invokes large amount of computation,more than 70 percent of total rendering time is spent in calculating the intersections between rays and *** volume is a commonly used technique for reducing the computation time, but this necessitates intersecting rays with bounding *** new algorithm avoids the initial intersection tests between primary rays and bounding volumes by polygon projection with little extra *** this technique,the bounding volumes can be constructed as tightly as one *** show that the new algorithm is very efficient.

关键词： ss:ray tracing polygon projection convex hull bounding volume

Structure determination of novel amminelithium(Ⅰ) borohydride for hydrogen/ammonia storage by charge flipping

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Structure determination of novel amminelithium(Ⅰ) borohydri...

ANALYSIS OF COMMUNITY STRUCTURE AND BIODIVERSITY IN THE FRAGEMENTATION VEGETATION IN hangzhou

第十届全国X射线衍射学术大会暨国际衍射数据中心（ICDD）研讨会

作者： Yihan Zhu Yanhui Guo,Guanglie Lv~§,Guanglin Xia,Liang Gao~,Xuebin Yu~ and Weimin Lu~ Institute of Catalysis,zhejiang university,hangzhou 310000,china Department of Materials Science,Fudan university,Shanghai 200433,china§zhejiang university National Science Park,hangzhou 310027,china

Recently,ammonia complexes of metal borohydrides M(BH4)·nNH showed potential for solid hydrogen storage materials.A good example reported by Soloveichik et *** Mg(BH)·2NH, which has a hydrogen capacity of 16.0 wt%and start to release hydrogen below 150℃.And so far,M(BH)·nNH complexes are known to be stable at room temperature for M= Li,Be,Mg,Ca, Zn,Cd,Al,Sc,Y,Ti,Zr,Cr,Co and *** them,one of ammonia complexes of lithium

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ANALYSIS OF COMMUNITY STRUCTURE AND BIODIVERSITY IN THE FRAG...

第三世界生态高峰会

作者： Chen B.~1 Da L.J~2 Yang Y.Y.~3 Shang K.K.~2 1 Department of Resource and Environmental sciences,School of Life and Environmental sciences,hangzhou Teachers college,hangzhou,zhejiang,310036 2 Department of Environmental Science,East china Normal university 3 Faculty of Urban Construction and Environmental Engineering,Chongqing university/Key Lab of Three Gorges Reservoir Region's Eco-Environment (Chongqing university),Ministry of Education,Chongqing

The urban vegetation dynamic and conservation were paid much attention during the last *** analyzed the fragmented vegetation characteristics in hangzhou city based on the field sampling in 2004 and 2005 to evaluate fragmentation *** city of hangzhou（29°ll′～30。34′N,118°20′～120°37′ E）,a fast developing city as a economic and tourism centre,is located at subtropical area of the East *** annual temperature is 15.3°C -17°C,and annual sum precipitation is *** set up a sampling transect in the fragment vegetation in Maojiabu,hangzhou city.A total of 18 plots（20×20m）were included in the transect,and every 20×20m plot was divided into four 10×10m subplots and sixteen 5×5m *** each plot,we recorded the tree species with height （?）1.5m,including the number of individual,height and mean tree diameter at breast height（1.3m,D.B.H）.The shrub species and herb species measure were conducted in 10×10m subplots and 5×5m *** on the data recorded,we analysed the important value of species,Shannon-Wiener diversity index,Simpson diversity index, Evenness index,*** and height distribution of the main species.27,48 and 78 plant species were respectively recorded in the tree,shrub（including several young tree）and herb layer（inclnding tree seedling and shrub seedling）,*** Shannon-Wiener diversity index of the herb layer was higher than that of the tree layer, the Shannon-Wiener diversity index of tree layer,shrub layer and herb layer were respectively 1.803,1.915 and 2.691,evenness index of the three layer were respectively 0.846,0.838 and *** important value of every species,the dominant families were Fagaceae and Theaceae in tree layer and shrub layer,and ferns,Theaceae dominant distributed in the herb *** Fagaceae and Theaceae are also dominantly elements in the subtropical vegetation of East china. The frequency distribution of height and DBH were different among the dominant tree species,their pop

关键词： ANALYSIS OF COMMUNITY STRUCTURE AND BIODIVERSITY IN THE FRAGEMENTATION VEGETATION IN hangzhou

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论新规则对排球接发球技术运用的影响及训练

武汉体育学院学报 2000年第6期34卷 62-64页

作者：李宁浙江大学西溪校区体育部浙江杭州310028

重视接发球技术 ,注重非规格化接发球技术的运用 ,加强发—垫球对抗训练、专项身体素质训练、心理训练等。

关键词：排球规则非规格化技术心理训练

Temporal-Spatial Variability of Soil Organic Carbon Stocks in a Rehabilitating Ecosystem

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Pedosphere 2004年第4期14卷 501-508页

作者： ZHANGShi-Rong SUNBo ZHAOQi-Guo XIAOPeng-Fei SHUJian-Ying InstituteofSoilScience ChineseAcademyofSciencesNanjing210008（China）. collegeofResourcesandEnvironment SichuanAgriculturalUniversityYa＇an625014（China）

In global change research, changes of soil organic carbon (SOC) reservoirs intropical and subtropical regions are still unknown. The temporal-spatial variability of SOC stockswas determined in a basin of over 579 km^2 in subtropical china from 1981to 2002. ArcGIS8.l softwarewas utilized for spatial analysis of semivariance, ordinary kriging (OK), and probability kriging(PK). Grid and hierarchical approaches were employed for the sampling scenario in 2002 with 106Global Position System (GPS) established spots sampled. Bulk topsoil samples (0—30 cm) werecollected at three random sites on each spot. The SOC content for 1981 came from the SOC map of theSecond National Soil Survey. Geostatistical results of the nugget to sill ratio (0.215-0.640)in therehabilitating ecosystem indicated a moderate spatial dependence for SOC on this large scale. Therange of SOC changed from 2.04 km in 1981 to 7.15 km in 2002. The mean topsoil SOC increased by 4.6%from 10.63 g kg^(-1) (1981) to 11.12 g kg^(-1)(2002). However, during this 21-year period 25.2% ofthe total basin area experienced a decrease in SOC. Also, the probability kriging results showedthat the geometric mean probabilities of SOC 15.0 gkg^(-1) were 0.188, 0.534 and 0.378, respectively in 2002, comparing to 0.234, 0.416 and 0.234 inthat order in 1981, respectively. The SOC storage in the topsoil increased by 17.0% during this timewith the main increase occurring in forests and cultivated land,which amounted to 82.5% and 17.0%of the total increase, respectively.

关键词： ordinary kriging probability kriging rehabilitating ecosystem soil organiccarbon temporal-spatial variability

A study on environmental aridity over northern and southern to Qinling Mountains under climate warming

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Journal of Geographical sciences 2001年第2期11卷 193-201页

作者： YAN Jun-ping~1, LIU Yan-sui~2 (1. college of Tourism and Environment, Shaanxi Normal university, Xi’an 710062, china 2. Institute of Geographic sciences and Natural Resources Research, CAS, Beijing 100101, china) college of Tourism and Environment Shaanxi Normal University Institute of Geographic sciences and Natural Resources Research CAS

Based on the data up to 1999 from hydroclimatological departments, this pape analyzes the climatic divide implications of the Qinling Mountains in regional response to the process of climate warming, due to which the grades of dryness/wetness (GDW) in 100 years show that the northern region has entered a drought period, while the southern is a humid period. In a course of ten years, the D-value of annual average air temperature over southern Shaanxi (the Hanjiang Valley) and the Central Shaanxi Plain (the Guanzhong Plain) has narrowed, i.e., the former with a slight change and the latter with rapid increase in temperature. Both regions were arid with the decrease in precipition D-value, namely the plain became warmer while the south was drier. The Qinling Mountains play a pronounced role in the climatic divide. The runoff coefficient (RC) of the Weihe River decreases synchronously with that of the Hanjiang due to climate warming. The RC of Weihe dropped from 0.2 in the 1950s to less than 0.1 in the 1990s. The Weihe Valley (the Guanzhong Plain) is practically an arid area due to shortage of water. The successive 0.5, 1.0°C temperature anomaly over china marks, perhaps, the improtant transition period in which the environment becomes more vulnerable than before. The study shows the obvious trend of environmental aridity, which is of help to the understanding of regional response to global climate change.

关键词： climate change aridity Qinling Mountains