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灾后村庄重建:公共产品性质变异及其供给特点 被引量:3
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作者 李雪萍 《华中师范大学学报(人文社会科学版)》 CSSCI 北大核心 2010年第5期39-46,共8页
学术界就公共产品性质的研究,由"公私二分法"到"二维连续分布",皆关注产品的原始属性;英格.考尔等认为产品性质在很大程度上由政策及其他集体行动来决定,即是一种社会建构。社会建构中,产品性质发生变异,均衡性公... 学术界就公共产品性质的研究,由"公私二分法"到"二维连续分布",皆关注产品的原始属性;英格.考尔等认为产品性质在很大程度上由政策及其他集体行动来决定,即是一种社会建构。社会建构中,产品性质发生变异,均衡性公共产品是其典型。灾后村庄公共产品供给中,产品性质变异:私人产品转化为纯公共产品、准公共产品,准公共产品向纯公共产品靠拢。性质变异后,公共产品供给呈现出新特点:主要供给基本生活资料,很强的时效性,无偿性,普及性,强制性。 展开更多
关键词 灾后重建 公共产品供给 性质变异
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四川雨城区主要土壤母质上的耕地土壤性质变异研究 被引量:5
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作者 胡玉福 邓良基 +1 位作者 张世熔 马其芳 《土壤通报》 CAS CSCD 北大核心 2004年第3期246-250,共5页
通过在四川省雨城区采集侏罗系沙溪庙组(J2s)、侏罗系遂宁组(J3s)、侏罗系蓬莱镇组(J3p)、白垩系夹关组(K2j)等地层9种母质上发育的耕地土壤样品共55个,并进行土壤性质测定及对比分析,结果表明:白垩系夹关组紫色砂岩上发育的耕地土壤较... 通过在四川省雨城区采集侏罗系沙溪庙组(J2s)、侏罗系遂宁组(J3s)、侏罗系蓬莱镇组(J3p)、白垩系夹关组(K2j)等地层9种母质上发育的耕地土壤样品共55个,并进行土壤性质测定及对比分析,结果表明:白垩系夹关组紫色砂岩上发育的耕地土壤较其他紫色母岩上发育的耕地砂粒含量高,pH低,养分含量低;第三系名山群及白垩系灌口组上发育的耕地土壤具有较其他母质高的土壤全钾;青衣江灰色河流冲积物发育的耕地土壤较其他母质发育的耕地土壤全磷和速效磷含量高,第四系冰水沉积物上发育的耕地土壤pH最低,粘粒含量高,土壤有机质及全氮、速效氮较其他母质发育的耕地土壤高。 展开更多
关键词 四川 土壤母质 土壤性质变异 土壤颗粒 土壤养分 土壤速效养分
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汉字变异的人类学背景
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作者 赵丽明 《广西民族学院学报(哲学社会科学版)》 CSSCI 北大核心 2001年第3期2-9,共8页
数千年来 ,汉字在约定俗成和不断规范中形成了自己的体制原则。它在周边民族和国家的使用与传播中 ,由于不同的文化背景 ,发生了种种变异 ,经历了五种形态 :汉字汉文→汉字某 (民族 )文→某族汉字→自创民族文字→新“书同文”和大字符... 数千年来 ,汉字在约定俗成和不断规范中形成了自己的体制原则。它在周边民族和国家的使用与传播中 ,由于不同的文化背景 ,发生了种种变异 ,经历了五种形态 :汉字汉文→汉字某 (民族 )文→某族汉字→自创民族文字→新“书同文”和大字符集建设 ,并因而形成了汉字系文字以及使用汉字系文字的国际区域。汉字的这种变异与地理、历史、儒学、宗教、民族等东方文化背景有关 ,并呈现出层次性、离合性。 展开更多
关键词 汉字体制 汉字传播 汉字变异 功能变异 形符变异 语义变异 性质变异 变异规律 离合性 文化背景
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2-酰基-1,3-环二酮类化合物互变异构的理论计算
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作者 王艳花 邹建卫 +3 位作者 张兵 曾敏 马国正 俞庆森 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2004年第8期952-956,共5页
采用MP2/6-31+G**//B3LYP/6-31+G**方法,系统地研究了2-酰基-1,3-环二酮类化合物的互变异构性质,探讨了环的饱和性、环的大小、环上杂原子以及溶剂效应对各互变异构体相对稳定性的影响。结果表明:(1)未烯醇化的异构体由于无法形成分子... 采用MP2/6-31+G**//B3LYP/6-31+G**方法,系统地研究了2-酰基-1,3-环二酮类化合物的互变异构性质,探讨了环的饱和性、环的大小、环上杂原子以及溶剂效应对各互变异构体相对稳定性的影响。结果表明:(1)未烯醇化的异构体由于无法形成分子内氢键而具有较高的能量;(2)环上杂原子的推电子效应提高了邻位羰基氧上的负电荷,从而有利于相应环外烯醇式异构体的稳定;(3)对化合物3-酰基-1H-吡啶-2,4-二酮,3-酰基吡喃-2,4-二酮,2-酰基环戊-4-烯-1,3-二酮和3-酰基吡咯-2,4-二酮,由互变异构形成的环的芳香性在各异构体的相对稳定性中扮演着决定性的作用。 展开更多
关键词 2-酰基-1 3-环二酮类化合物 理论计算 变异性质 从头算 密度泛函
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Genetic variations of wood properties and growth characters of Ko-rean pines from different provenances 被引量:4
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作者 王慧梅 夏德安 +1 位作者 王文杰 杨书文 《Journal of Forestry Research》 SCIE CAS CSCD 2002年第4期277-280,337,共4页
Totally 26 provenance stands of 17-year-old Korean pine were selected for investigating wood properties and growth characters in Mao抏rshan Experimental Forest Farm of Northeast Forestry University in 1999. The anatom... Totally 26 provenance stands of 17-year-old Korean pine were selected for investigating wood properties and growth characters in Mao抏rshan Experimental Forest Farm of Northeast Forestry University in 1999. The anatomical property indexes, including tracheid length, tracheid diameter and wall-indiameter ratio, and the physical property indexes, such as growth ring width, late wood percentage and growth ring density, were measured for wood properties. Growth character indexes, including tree height and diameter at breast height, were also measured. The analytical results showed that there exited obviously dif-ference in wood property indexes between different provenances, which is suggested that wood properties are controlled by their genetic differences. The growth character indexes of Korean pines presented significant difference and they might also be controlled by their genetic differences. Most parameters of wood properties mainly varied in the direction of longitude, but the parameters of growth characters varied in the direction of latitude. 展开更多
关键词 Korean pine Provenance trial Wood properties Geographical variation Genetic variation
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Effects of Soil and Environment on Quality Traits of Purple-fleshed Sweetpotato 被引量:2
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作者 闫会 李强 +5 位作者 张允刚 王欣 刘亚菊 后猛 唐维 马代夫 《Agricultural Science & Technology》 CAS 2017年第3期516-520,523,共6页
For the study of main traits of purple-flashed sweetpotato in different soil and ecological environments, 18 cultivars of purple-flashed sweetpotato with different enthocyenin contents were planted at Yancheng and Xuz... For the study of main traits of purple-flashed sweetpotato in different soil and ecological environments, 18 cultivars of purple-flashed sweetpotato with different enthocyenin contents were planted at Yancheng and Xuzhou separately. The main quality traits were determined. The results showed the quality traits of purple-fleshed sweetpotato were significantly influenced by soil and ecological environments. Geno- type (G), environment (E) and genotype x environment (GxE) interaction had signif- icantiy effects on the contents of anthocyanin, dry matter, starch, protein, reducing sugar and soluble sugar in storage roots. Anthocyanin content was most easily af- fected by the environment. The E effect on anthocyanin content was greater than G and GxE effects. However, the GxE interaction effects on other 5 quality traits were greater than G and E effects. The 6 quality traits were significantly different at 1% level under different environments respectively. The contents of dry matter, starch and anthocyenin were higher in Yancheng than in Xuzhou, while the contents of protein, reducing sugar and soluble sugar were higher in Xuzhou. The variation co- efficients of all quality traits at Yancheng and Xuzhou were in the same order: an- sugar〉protein〉starch, the variation coefficient of anthocyanin content was higher in Xuzhou, and the variation coefficients of other 5 traits were higher in Yancheng. Correlation analysis showed that the reducing sugar and solu- ble sugar contents were negatively correlated with starch content, and had no sig- nifiant correlation with anthocyanin and protein contents. Dry matter content and starch content were positively correlated, and anthocyanin content and other quality traits had no significant correlation. 展开更多
关键词 Purple-fleshed sweetpotato Quality traits GENOTYPE ENVIRONMENT Varia-tion
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Vertical Variation Characteristics of Basic Physical Properties in the Daxia Irrigated Area of Qinghai Province
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作者 吕文星 唐洪波 +3 位作者 刘东旭 王国重 王玉明 李东 《Agricultural Science & Technology》 CAS 2015年第12期2859-2862,2865,共5页
Influenced by climate, biology and soil properties, vertical soil profile showed stratification character in terms of basic physical properties. The research conducted measurement and analysis on basic physical proper... Influenced by climate, biology and soil properties, vertical soil profile showed stratification character in terms of basic physical properties. The research conducted measurement and analysis on basic physical properties of typical field in the Daxia irrigation area in Qinghai Province. The results showed that soil bulk density changed from decreasing to increasing upon soil horizon; the soil horizons in 0-40 and 90-150 cm were high porosity zones, and the others were low porosi- ty area; the saturation moisture capacity, water retention of capillary porosity and field water retention all changed from decreasing to increasing upon soil horizon featured by arithmetic progression. In addition, the research area in Daxia irrigated area showed loose structure in soil horizon of 0-40 cm, compacted in 40-60 cm, and loose again in 60-200 cm vertically. 展开更多
关键词 Daxia irrigated area Soil basic physical properties Vertical variation
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Geographic variation and genetic performance of Picea koraiensis in growth and wood characteristics 被引量:5
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作者 WANGQiu-yu JIAHong-bai SHANGJie 《Journal of Forestry Research》 SCIE CAS CSCD 2005年第2期93-96,共4页
Eight provenances of 19-year-old Picea koraiensis Nakai from the provenancetrials of Maoershan (45°20′N, 127°30′E), Liang-shui (47°10′N, 128°53′E) and Jiagedaqi(50°24′N, 124°07′E) i... Eight provenances of 19-year-old Picea koraiensis Nakai from the provenancetrials of Maoershan (45°20′N, 127°30′E), Liang-shui (47°10′N, 128°53′E) and Jiagedaqi(50°24′N, 124°07′E) in Northeast China were investigated to analyze the genetic variation ingrowth characteristics (tree height and diameter) and wood characteristics (tracheid length,tracheid diameter, tracheid wall thickness, annual ring width as well as wood density). Greatvariation in height growth and breast height diameter growth was observed among the provenances, andalong with the increase of tree age, these provenances presented different geographic adaptability.The growth characteristics of Picea koraiensis stand at age of 10 in Maoershan and Liangshuiprovenance trials had a positive correlation with longitude, and with increase of tree age to 15 and19, the tree growth of the provenances displayed a significant positive correlation with latitudeas well as altitude. For wood characteristics, great variation was also found among the provenances.There exists a close relation between growth characteristics and wood properties of the provenance.The height and breast height diameter growth of the provenance had a positive correlation withtracheid diameter and annual ring width, and a negative correlation with tracheid wall thickness andwood density. Genetic performance of the provenance in all above characteristics was alsoinvestigated in order to provide more useful information for comprehensive selection of this speciesfor pulpwood and plywood production. 展开更多
关键词 picea koraiensis geographic variation genetic correlation growthcharacteristics wood characteristics
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Effect of Two Herbicides on the Growth of Early Seedlings of Rye(Secale cereale) 被引量:2
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作者 党晨 高越 《Agricultural Science & Technology》 CAS 2011年第8期1213-1216,共4页
[Objective]The aim was to study the effect of herbicide on the growth of early seedlings of rye(Secale cereale).[Method]Effect of two kinds of herbicide(Atrazine and APM)on seedling growth of rye was investigated ... [Objective]The aim was to study the effect of herbicide on the growth of early seedlings of rye(Secale cereale).[Method]Effect of two kinds of herbicide(Atrazine and APM)on seedling growth of rye was investigated at the physiological,biochemical and cellular level.[Result]The Atrazin significantly decreased the contents of chlorophyll a,b and soluble proteins.Rye seeds were treated with 0.01-1 mg/L Atrazine for 16 h,the contents of chlorophyll a and b decreased from 1.26(a),0.49(b)mg/g FW(control)to 1.15(a),0.46(b)mg/g FW(0.1 mg/L)and 0.81(a),0.33(b)mg/g FW(1.0 mg/L).The content of soluble protein decreased with the increasing concentration of Atrazin.Atrazin had no significant influence on the cell division and chromosome structure variation.The contents of chlorophyll a,b and soluble proteins had no significantly change under the treatment of APM,but the number of chromosome structure variation such as chromosome bridge,multipolar division cells,lagging chromosome and unequal division cells increased significantly.[Conclusion]The critical concentration of Atrazine was 0.1-1.0 mg/L and 4 mg/L of APM in rye. 展开更多
关键词 HERBICIDES Secale cereal Chlorophyll content Soluble protein Chromosome structure variation
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Evaluation of Spatial Variability of Soil Properties in a Long-Term Experimental Tobacco Station in Southwest China 被引量:1
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作者 Jiang Houlong Wang Hongfeng +6 位作者 Li Najia Xu Anding Yang Chao Chen Yiyin Li Yong Geng Lina Liu Guo-Shun 《Journal of Agricultural Science and Technology(A)》 2014年第9期723-735,共13页
Analysis of the spatial variability of soil properties is important to arrange the experimental treatments in the experimental station. This paper aims to study the spatial structure of soil variables and their distri... Analysis of the spatial variability of soil properties is important to arrange the experimental treatments in the experimental station. This paper aims to study the spatial structure of soil variables and their distribution in the Pengshui tobacco experiment station in Chongqing, China. Soil samples were taken from 289 soil points on 20 m grid in March 2012. Twenty-two soil chemical and physical properties were analyzed by classical statistical and geo-statistical methods. Soil pH, cation exchange capacity (CEC), total phosphorus (TP), available phosphorus (AP), zinc (Zn), magnesium (Mg) and sulphur (S) have the strong spatial dependence, with nugget/sill ratios of less than 25%. The others have the moderate dependence with nugget/sill ratios of 26.17% to 71.04%. Ranges of the spatial correlation varied from 51.30 m for chlorine (C1) to 594.90 m for TP. The clearly patchy maps of the nutrients showed the spatial distributions of the soil variables, which can be used for better management of experimental treatments, achieving reliable exoerimental results in the tobacco exnerimental station.Highlight: Scientific experimentation assumes the existence of random variability for soil attributes. This research was to evaluate the spatial variability of soil chemical and physical attributes and to interpolate the spatial distribution of soil properties in the tobacco experimental station in Chongqing. The result of this work can be used for the agricultural management of tobacco cultivation. 展开更多
关键词 Geo-statistical analysis soil property spatial variability tobacco experimental station.
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Modeling Strain Rate Effect for Heterogeneous Brittle Materials 被引量:1
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作者 MA Guowei DONG Aiai LI Jianchun 《Transactions of Tianjin University》 EI CAS 2006年第B09期79-82,共4页
Rocks are heterogeneous from the point of dynamic failure behavior. Both the compressive and microstructure which is of significance to their tensile strength of rock-like materials is regarded different from the stat... Rocks are heterogeneous from the point of dynamic failure behavior. Both the compressive and microstructure which is of significance to their tensile strength of rock-like materials is regarded different from the static strength. The present study adopts smoothed particle hydrodynamics (SPH) which is a virtual particle based meshfree method to investigate strain rate effect for heterogeneous brittle materials. The SPH method is capable of simulating rock fracture, free of the mesh constraint of the traditional FEM and FDM models. A pressure dependent J-H constitutive model involving heterogeneity is employed in the numerical modeling. The results show the compressive strength increases with the increase of strain rate as well as the tensile strength, which is important to the engineering design. 展开更多
关键词 HETEROGENEOUS strain rate effect SPH method
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Spatial heterogeneity in a deep artificial lake plankton community revealed by PCR-DGGE fingerprinting 被引量:8
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作者 李强 赵越 +4 位作者 张旭 魏雨泉 邱琳琳 魏自民 李富恒 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2015年第3期624-635,共12页
To explore the spatial heterogeneity of plankton communities in a deep artificial lake (Songhua Lake, China), samples were collected at seven sites. Samples were investigated by denaturing gradient gel electrophores... To explore the spatial heterogeneity of plankton communities in a deep artificial lake (Songhua Lake, China), samples were collected at seven sites. Samples were investigated by denaturing gradient gel electrophoresis (DGGE) analysis of the PCR-amplified 16S and 18S rRNA genes and specific bands were sequenced. Cluster analysis of the DGGE profiles revealed that all of the samples grouped into two distinct clusters, in accordance with sampling site; while in each cluster, the divergence of sub-clusters correlated with sampling depth. Sequence analysis of selected dominant DGGE bands revealed that most sequenced phylotypes (84%) exhibited 〉97% similarity to the closest sequences in GenBank, and were affiliated with ten common freshwater plankton phyla (Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, Bacillariophyta, Pyrrophyta, Cryptophyta, Ciliophora, Stramenopiles, and Rotifera). Several of these groups are also found worldwide, indicating the cosmopolitan distribution of the phylotypes. The relationships between DGGE patterns and environmental factors were analyzed by redundancy analysis (RDA). The results suggested that, total nitrogen, nitrate, nitrite, temperature were strongly correlated with the variation ammonia, and CODMn concentrations, and water in plankton composition. 展开更多
关键词 Songhua Lake plankton community composition denaturing gradient gel electrophorcsis (DGGE) artificial lake redundancy analysis
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Heteroplasmy Level of the Mitochondrial tRNA^(Leu(UUR)) A3243G Mutation in a Chinese Family Is Positively Associated with Earlier Age-of-onset and Increasing Severity of Diabetes 被引量:5
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作者 Shi Zhang An-li Tong Yun Zhang Min Nie Yu-xiu Li Heng Wang 《Chinese Medical Sciences Journal》 CAS CSCD 2009年第1期20-25,共6页
Objective To investigate the mutations of mitochondrial genome in a pedigree with suspected maternally inherited diabetes and deafness and to explore the correlations between the mutations and clinical features. Meth... Objective To investigate the mutations of mitochondrial genome in a pedigree with suspected maternally inherited diabetes and deafness and to explore the correlations between the mutations and clinical features. Methods Genomic DNA was isolated from blood leucocytes of each member of the pedigree. The mitochondrial genome was amplified with 24-pair primers that could cover the entire mitochondrial DNA. Direct sequencing of PCR products was used to identify any mitochondrial DNA mutations. Results Family members on the maternal side all harbored the tRNA^Lcu(UUR) A3243G mutation. The paternal side family members did not have the mutation. The age-of-onset of diabetes of the 4 maternal side family members was 15, 41, 44, and 65 years old, and their corresponding heteroplasmy level of the mutation was 34.5%, 14.9%, 14.6%, and 5.9%, respectively. The age-of-onset of diabetes and heteroplasmy level of A3243G mutation were negatively correlated with a correlation coefficient of -0.980(P=0.02). Meanwhile, patient with high heteroplasmy level of A3243G mutation had relatively low severity of disease. Moreover, 6 reported polymorphisms and 2 new variants were found. Conclusions The main cause of diabetes in this pedigree is the tRNA^Lcu(UUR) A3243G mutation. However, other gene variants may contribute to its pathogenicity. The heteroplasmy level of the tRNA^Lcu(UUR) A3243G mutation is positively associated with earlier age-of-onset and increasing severity of diabetes. 展开更多
关键词 maternally inherited diabetes and deafness tRNA^Lcu(UUR) A3243G mutation beteroplasmy
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Spatio-temporal Variation of Landscape Heterogeneity under Influence of Human Activities in Xiamen City of China in Recent Decade 被引量:3
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作者 HUANG Yixiong YIN Xiuqin +5 位作者 YE Gongfu LIN Jiemin HUANG Ru WANG Na WANG Liang SUN Yue 《Chinese Geographical Science》 SCIE CSCD 2013年第2期227-236,共10页
Xiamen is an economically competitive and highly urbanized city along the coastal area of Fujian Province, China. The research on spatio-temporal variation of landscape heterogeneity under the influence of human activ... Xiamen is an economically competitive and highly urbanized city along the coastal area of Fujian Province, China. The research on spatio-temporal variation of landscape heterogeneity under the influence of human activities is of great importance to the further study on the relationship of landscape pattern and ecological process. It is also crucial to the discovery of spatial variation and intensity distribution of human activities. The research analyzed the intensity of human impacts and the spatial variation features and dynamics of landscape patterns by introducing statistical theories and approaches. We analyzed spatio-temporal variation of landscape heterogeneity using the geostatistical techniques, such as semivariogram and Kriging interpolation.Results show that there is a higher correlation between landscape heterogeneity indexes and human impact index. Both the indexes show a moderate spatial autocorrelation as well as an obvious characteristic of anisotropy. From 1998 to 2008, the spatial differentiation of the changes in the intensity of human activities and the changes in landscape heterogeneity shows that the landscape patterns in Xiamen are closely related with the urban land utilization methods, the condition of traffic and geographical location and the physical geographical condition such as the terrain and the ecological environment. The process of urbanization has a significant impact on the urban landscape pattern. 展开更多
关键词 landscape heterogeneity human impact index human activities Xiamen City
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Characterizing Landscape Spatial Heterogeneity in Multisensor Images with Variogram Models
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作者 QIU Bingwen ZENG Canying +3 位作者 CHENG Chongcheng TANG Zhenghong GAO Jianyang SUI Yinpo 《Chinese Geographical Science》 SCIE CSCD 2014年第3期317-327,共11页
Most evaluation of the consistency of multisensor images have focused on Normalized Difference Vegetation Index (NDVI) products for natural landscapes, often neglecting less vegetated urban landscapes. This gap has ... Most evaluation of the consistency of multisensor images have focused on Normalized Difference Vegetation Index (NDVI) products for natural landscapes, often neglecting less vegetated urban landscapes. This gap has been filled through quantifying and evaluating spatial heterogeneity of urban and natural landscapes from QuickBird, Satellite pour l'observation de la Terre (SPOT), Ad- vanced Spacebome Thermal Emission and Reflection Radiometer (ASTER) and Landsat Thematic Mapper (TM) images with variogram analysis. Instead of a logarithmic relationship with pixel size observed in the corresponding aggregated images, the spatial variability decayed and the spatial structures decomposed more slowly and complexly with spatial resolution for real multisensor im- ages. As the spatial resolution increased, the proportion of spatial variability of the smaller spatial structure decreased quickly and only a larger spatial structure was observed at very coarse scales. Compared with visible band, greater spatial variability was observed in near infrared band for both densely and less densely vegetated landscapes. The influence of image size on spatial heterogeneity was highly dependent on whether the empirical sernivariogram reached its sill within the original image size. When the empirical semivariogram did not reach its sill at the original observation scale, spatial variability and mean characteristic length scale would increase with image size; otherwise they might decrease. This study could provide new insights into the knowledge of spatial heterogeneity in real multisen- sor images with consideration of their nominal spatial resolution, image size and spectral bands. 展开更多
关键词 variogram modeling spatial heterogeneity characteristic scale multisensor image
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Effect of Heterogeneities in Soil on Spatial Variation of Peak Ground Acceleration
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作者 Mohammad Ahmed Hussain Ramancharla Pradeep Kumar 《Journal of Civil Engineering and Architecture》 2010年第11期45-52,共8页
In the proximity of an active fault, spatial variation of peak ground motion is significantly affected by the faulting mechanism. It has been observed that near fault ground motions consists of different characteristi... In the proximity of an active fault, spatial variation of peak ground motion is significantly affected by the faulting mechanism. It has been observed that near fault ground motions consists of different characteristics compared to the far fault ground motions. Near fault records, in the distance range of less than 100 m from the faults are not available except for few cases. Therefore numerical simulation of ground motions for such near-fault situations is necessary. In addition to the understanding of the phenomenon of near fault ground motion there is a need to enhance our understanding of the possible potential hazard that can be caused due to the future rupture activity by understanding the phenomenon of surface faulting. In this paper we propose numerical simulation based on discrete modeling to investigate the fault rupture propagation and its effect on the surface peak ground acceleration. In the present two dimensional study rupture propagation due to bedrock motion has been observed for different shear wave velocity. A model of size 1000× 150 m is selected for this purpose. It has been observed that as the stiffness of the media is decreasing, the affected surface is decreasing and also width of the shear crack zone is decreasing. Secondly, we attempted to study the ground motion on the surface due to the bedrock motion in presence of boulders in the soil media by keeping the boulder at different positions. We find that there is an increase in the shear zone as well as the PGA on the surface when the boulder is present on the foot wall and in the vicinity of the rupture zone. Finally, we performed the analysis using layered media and studied the affect of crack propagation and also the variation of peak accelerations. Findings from the study can be utilized to assess the damage potential of the near fault areas. 展开更多
关键词 PGA HETEROGENEITIES AMPLIFICATION fault motion.
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Effects of axial cyclic loading at constant confining pressures on deformational characteristics of anisotropic argillite 被引量:2
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作者 张久长 周苏华 +1 位作者 方理刚 许湘华 《Journal of Central South University》 SCIE EI CAS 2013年第3期799-811,共13页
Triaxial cyclic loading tests have been performed to assess the influence of plastic deformation on inelastic deformational properties of anisotropic argillite with bedding planes which is regarded as a kind of transv... Triaxial cyclic loading tests have been performed to assess the influence of plastic deformation on inelastic deformational properties of anisotropic argillite with bedding planes which is regarded as a kind of transversely isotropic media.Considering argillite's anisotropy and inelastic deformational properties,theoretical formulae for calculating oriented elastic parameters were deduced by the unloading curves,which can be better fitted for the description of its elasticity than loading curves.Test results indicate that with the growth of accumulated plastic,strain,the apparent elastic modulus of argillite decreases in a form of exponential decay function,whereas the apparent Poisson ratio increase in a form of power equation.A ratio of unloading recoverable strain to the total strain increment occurred during a loading cycle is defined to illustrate the characteristic relations between anisotropic coupled elasto-plastic deformation and plastic strain.It is significant to observe that high stress level and plastic history have an inhibiting effect on argillite anisotropy. 展开更多
关键词 anisotropic argillite coupled elasto-plasticity cyclic loading tests elastic parameters plastic strain
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An EMD based method for detrending RR interval series without resampling
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作者 曾超 蒋奇云 +1 位作者 陈朝阳 徐敏 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第2期567-574,共8页
Slow trends in the RR interval(RRI) series should be removed in the preprocessing step to get a reliable result of heart rate variability(HRV) analysis. Re-sampling is required to convert the unevenly sampled RRI seri... Slow trends in the RR interval(RRI) series should be removed in the preprocessing step to get a reliable result of heart rate variability(HRV) analysis. Re-sampling is required to convert the unevenly sampled RRI series into evenly sampled time series when using the widely accepted smoothness priors approach(SPA). Noise is introduced in this process and the information quality is thus compromised. Empirical mode decomposition(EMD) and its variants, were introduced to directly process the unevenly sampled RRI series. Besides, a RR interval model was proposed to fascinate the introduction of standard metrics for the evaluation of the detrending performance. Based on standard metrics including signal-to-noise-ratio in d B(ISNR), mean square error(EMS), and percent root square difference(DPRS), the effectiveness of detrending methods in RR interval analysis were determined. Results demonstrate that complementary ensemble EMD(CEEMD, a variant of EMD) based method has a higher ISNR, a lower EMS and a lower DPRS as well as a better RRI series detrending performance compared with the SPA method, which would in turn lead to a more accurate HRV analysis. 展开更多
关键词 heart rate variability empirical mode decomposition DETRENDING RR interval model
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Impact of Rainfall Temporal Heterogeneity on Relationship between Curve Number and Rainfall Depth in the Zagros Mountain Region,Iran
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作者 Hassan REZAEI-SADR 《Journal of Mountain Science》 SCIE CSCD 2015年第3期689-698,共10页
The impact of temporal variation of rainfall on the relationship between rainfall and catchment response is investigated in a catchment with high temporally variable rainfalls and a high percentage of permeable soils ... The impact of temporal variation of rainfall on the relationship between rainfall and catchment response is investigated in a catchment with high temporally variable rainfalls and a high percentage of permeable soils in the southwest of Iran.Twenty-nine storm events are classified into two classes, High Temporal heterogeneous(HT) and Low Temporal heterogeneous(LT) events using the variogram technique and the storm events of each class are analyzed to detect the relationship between Curve Number(CN) and rainfall depth. It is found that there is not a similar correlation between CN values and rainfall depths for both temporally variable classes, and hence, two different responses can be observed in the catchment according to rainfall temporal heterogeneities. For HT events, a complacent behavior is detected in which the CNs decline as rainfall depth increases while a different response, violent behavior, is observed for LT events in which the CNs rise and asymptotically approach a constant value with increasing storm size. This considerable difference between CN-P relationships derived from the two temporally variable classes of rainfall is attributed to the provocation of different runoff generation mechanisms, infiltration-excess and saturation-excess caused by rainfall temporal heterogeneities. Moreover, the results support the validity of variogram technique to classify storm events into two LT and HT classes. 展开更多
关键词 Asymptotic approach Curve Numbermethod Infiltration-excess Rainfall temporalvariation Saturation-excess Variogram technique
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On the instability of offshore foundations: theory and mechanism 被引量:4
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作者 GAO FuPing LI JinHui +1 位作者 QI WenGang HU Cun 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2015年第12期125-141,共17页
As the offshore engineering moving from shallow to deep waters, the foundation types for fixed and floating platforms have been gradually evolving to minimize engineering costs and structural risks in the harsh offsho... As the offshore engineering moving from shallow to deep waters, the foundation types for fixed and floating platforms have been gradually evolving to minimize engineering costs and structural risks in the harsh offshore environments. Particular focus of this paper is on the foundation instability and its failure mechanisms as well as the relevant theory advances for the prevailing foundation types in both shallow and deep water depths. Piles, spudcans, gravity bases, suction caissons, and plate anchors are detailed in this paper. The failure phenomena and mechanisms for each type of foundations are identified and summarized, respectively. The theoretical approaches along with sophisticated empirical solutions for the bearing capacity problems are then presented. The major challenges are from flow-structure-soil coupling processes, rigorous constitutive modeling of cyclic behaviors of marine sediments, and the spatial variability of soil properties for large-spreading structures. Further researches are suggested to reveal the instability mechanisms for underpinning the evolution of offshore foundations. 展开更多
关键词 failure mechanism bearing capacity fluid-structure interaction offshore foundation soil dynamics
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