期刊文献+
共找到60篇文章
< 1 2 3 >
每页显示 20 50 100
北秦岭斜峪关群和草滩沟群火山岩成因的地球化学和同位素约束、SHRIMP年代及其意义 被引量:63
1
作者 闫全人 王宗起 +5 位作者 陈隽璐 闫臻 王涛 李秋根 姜春发 张宗清 《地质学报》 EI CAS CSCD 北大核心 2007年第4期488-500,I0007-I0008,共15页
地球化学分析结果表明:北秦岭斜峪关群基性熔岩的LREE轻度富集,(La/Yb)N=1.31~3.27,中—酸性熔岩的LREE显著富集,(La/Yb)N=4.22~26.54。草滩沟群基性火山岩LREE中度富集,(La/Yb)N=2.50~2.97,中—酸性熔岩的LREE显著富集,(La/Yb)N=4.57~1... 地球化学分析结果表明:北秦岭斜峪关群基性熔岩的LREE轻度富集,(La/Yb)N=1.31~3.27,中—酸性熔岩的LREE显著富集,(La/Yb)N=4.22~26.54。草滩沟群基性火山岩LREE中度富集,(La/Yb)N=2.50~2.97,中—酸性熔岩的LREE显著富集,(La/Yb)N=4.57~10.15。低δEu值(0.62~1.14)暗示斜峪关群和草滩沟群火山岩初始玄武质岩浆的分离结晶程度很低、初始岩浆中斜长石分异作用很弱,大离子亲石元素明显富集,而相对N-MORB较低的高场强元素丰度,特别是明显的Ta、Nb低谷,展示了典型的岛弧火山岩的特征。同位素地球化学分析揭示,斜峪关群和草滩沟群火山岩的初始Sr比值为0.703438~0.708329,初始Nd比值为0.511948~0.512327,多集中于0.512003~0.512327间,εNd均为正值(+5.42^+12.81),表明二群火山岩主要来自富集地幔源区。斜峪关群和草滩沟群火山岩的岩浆源区为混染的富集地幔源区,是俯冲板片熔融和地壳混染的产物,形成于岛弧构造环境。SHRIMP锆石U-Pb测年表明斜峪关群基性熔岩形成时代为早奥陶世(472±11Ma),其中的古老捕晶锆石(1294±34Ma)表明斜峪关群火山岩的岩浆源区存在元古宙地壳混染。 展开更多
关键词 斜峪关群 草滩沟群 火山岩 SHRIMP测年 地球化学 SR-ND-PB同位素 构造环境 秦岭
下载PDF
皖南地区歙县岩群昌前岩组和昱岭关群井潭组凝灰岩SHRIMP锆石U-Pb年龄及其地质意义 被引量:4
2
作者 龚成强 张恒 +1 位作者 丁孝忠 高林志 《岩石矿物学杂志》 CAS CSCD 北大核心 2019年第4期465-476,共12页
江南造山带东北段歙县岩群和昱岭关群是皖南地区重要的前寒武纪地层单元。本文对皖南地区歙县岩群昌前岩组和昱岭关群井潭组凝灰岩样品中的锆石进行了测年研究,获得昌前岩组凝灰岩SHRIMP锆石U-Pb年龄为852±6 Ma和840±11Ma,井... 江南造山带东北段歙县岩群和昱岭关群是皖南地区重要的前寒武纪地层单元。本文对皖南地区歙县岩群昌前岩组和昱岭关群井潭组凝灰岩样品中的锆石进行了测年研究,获得昌前岩组凝灰岩SHRIMP锆石U-Pb年龄为852±6 Ma和840±11Ma,井潭组凝灰岩SHRIMP锆石U-Pb年龄为809±10 Ma,为皖南地区新元古代地层格架的建立和地层的对比增添了可靠的年代学依据。根据最新获得的锆石U-Pb年龄数据,确定歙县岩群的时代与江南造山带区域范围内梵净山群、四堡群、冷家溪群、双桥山群以及溪口岩群相当,其上覆的昱岭关群与下江群、丹洲群、板溪群、马涧桥组、登山群以及上墅组等地层单元可以对比。 展开更多
关键词 皖南地区 歙县岩群 昱岭关群 凝灰岩 SHRIMP锆石U-PB年龄
下载PDF
北秦岭西部铜峪VHMS型铜矿床地质-地球化学特征与成矿动力学背景 被引量:2
3
作者 朱赖民 李犇 +2 位作者 张国伟 弓虎军 郭波 《矿床地质》 CAS CSCD 北大核心 2010年第S1期377-378,共2页
已有研究已充分证明,商丹带是秦岭主造山期板块的俯冲碰撞缝合带,商丹一线曾有一个消失的有限洋盆,商丹带就是其消亡的俯冲碰撞缝合线。华北地块南缘呈现出由南向北依次为从商丹俯冲带、秦岭杂岩为基底的岛弧火山岩与花岗岩带到二郎坪... 已有研究已充分证明,商丹带是秦岭主造山期板块的俯冲碰撞缝合带,商丹一线曾有一个消失的有限洋盆,商丹带就是其消亡的俯冲碰撞缝合线。华北地块南缘呈现出由南向北依次为从商丹俯冲带、秦岭杂岩为基底的岛弧火山岩与花岗岩带到二郎坪弧后边缘海盆带,构成与活动大陆边缘类似的沟-弧-盆构造体系。早古生代秦岭商丹洋洋壳俯冲导致北秦岭岛弧造山带的发育,岛弧造山过程起始于洋壳的俯冲消减。 展开更多
关键词 矿床地质 成矿动力学背景 地球化学特征 北秦岭 岛弧火山岩 铜矿床 古秦岭洋 斜峪关群 商丹带 俯冲碰撞
下载PDF
秦岭三叠纪岩相古地理特征 被引量:2
4
作者 殷鸿福 赖旭龙 《矿物岩石地球化学通报》 CAS CSCD 1991年第4期246-247,共2页
秦岭三叠纪是该区海相沉积的最后阶段,正确认识其沉积发展史对了解秦岭地区的构造历史有着十分重要的作用。但其研究程度很低。由于缺乏确凿的古生物证据,许多地区(图幅)的三叠系仅分到群或岩组,有的群(如官亭群)的时代、归属不明,在地... 秦岭三叠纪是该区海相沉积的最后阶段,正确认识其沉积发展史对了解秦岭地区的构造历史有着十分重要的作用。但其研究程度很低。由于缺乏确凿的古生物证据,许多地区(图幅)的三叠系仅分到群或岩组,有的群(如官亭群)的时代、归属不明,在地质图上仅标以临时性代号,图幅之间不能对接。过去由于缺乏完整的地层层序,对该区三叠纪沉积学尤其是岩相古地理学的研究存在着极大困难。李继亮等(1978)、姜春发等(1979)对东秦岭陕西凤县留凤关群作了详细研究后,认为留凤关群为早三叠世复理石(浊积岩)沉积,给人们留下“秦岭三叠系是一套活动类型的复理石沉积”的印象,然事实上不尽然。 展开更多
关键词 岩相古地理 留凤关群 秦岭地区 浊积岩 早三叠世 地层层序 复理石建造 岩组 图幅 沉积学
下载PDF
析产业集群的财务协同效应 被引量:1
5
作者 姚贞 《商场现代化》 北大核心 2008年第12期263-263,共1页
产业集群是区域经济增长的动力。产业集群的竞争力是其协同效应的结果。在产业集群的整体生产经营中,资金流的流畅与否起着极其重要的作用。因此,产业集群的发展要充分利用其财务协同效应,降低成本和风险,提高成员企业和产业集群整体的... 产业集群是区域经济增长的动力。产业集群的竞争力是其协同效应的结果。在产业集群的整体生产经营中,资金流的流畅与否起着极其重要的作用。因此,产业集群的发展要充分利用其财务协同效应,降低成本和风险,提高成员企业和产业集群整体的核心竞争力。 展开更多
关键词 财务协同 产业关群 成本
下载PDF
Distributional patterns of species diversity of main plant communities along altitudinal gradient in secondary forest region,Guandi Mountain,China 被引量:7
6
作者 高俊峰 张芸香 《Journal of Forestry Research》 SCIE CAS CSCD 2006年第2期111-115,共5页
Fourteen plots were chosen along with the altitude of 1600-2600 m in Guandi Mountain, Shanxi Province, China to investigate all the trees in the plots, and the species diversity indexes were calculated for analyzing t... Fourteen plots were chosen along with the altitude of 1600-2600 m in Guandi Mountain, Shanxi Province, China to investigate all the trees in the plots, and the species diversity indexes were calculated for analyzing the effects of altitudinal gradient on plant species diversity. The results showed that the order of dominant species from low altitude to high altitude is as Quercus liaotungensis Koidz, Pinus tabulaeformis, Betula platyphylla, B. albo-sinensis, Picea wilsonii, P. Meyeri and Larix principis-rupprechtii. With altitude increasing, the average height and DBH of the arbor firstly increase and then decrease, the maximal height and DBH of the arbor present the unimodal variable trend, the maximal height of coniferous and broad-leaved trees firstly increases and then decreases, the maximal DBH of broad-leaf trees has no clear fluctuation, and the maximal DBH of the needle-leaf trees decreases gradually. Moreover, in middle altitudinal communities (the altitude of 1900-2200 m), the maximal height and DBH of the needle-leaf trees are larger than these of broad-leaf trees. Both Shannon-wiener index and Margalef index of the communities present the unimodal variable trend, with a peak in the mid-altitude. Plant species diversity in the mid-altitude (1900-2200 m) is higher than that of the low altitude (1600-1900 m) and the high altitude (2200-2600 m). In addition, the unimodal variable trend of α species diversity is clearly correlated with the altitudinal gradient. The change of plant species diversity is significantly correlated with the altitudinal gradient, and also related to the community structure, the community composition, the feature of species and the human disturbance. 展开更多
关键词 Species diversity Altitudinal gradient COMMUNITY Guandii Mountain
下载PDF
中国高等教育学会体育研究会’95北京学术论文报告会综述
7
作者 曹宝源 《体育学刊》 CAS 1995年第4期7-7,共1页
此届学术论文报告会在国家教委、北京高教局的支持、指导下,于10月9—11日在清华大学召开。在党中央、国务院以“科技兴国”为决策的精神鼓舞下召开的这届报告会,必将推动我国高等学校体育事业的发展。 这次论文报告会共收到征文128篇,... 此届学术论文报告会在国家教委、北京高教局的支持、指导下,于10月9—11日在清华大学召开。在党中央、国务院以“科技兴国”为决策的精神鼓舞下召开的这届报告会,必将推动我国高等学校体育事业的发展。 这次论文报告会共收到征文128篇,承蒙惠州大学领导协助,于7月7—11日,由来自全国高校的专家教授,以学会副理事长朱丰诚同志为领导组成了16人的评审组。经过评委会认真评选,共录取了58篇论文, 展开更多
关键词 中国高等教育学会 体育研究 北京学 报告会 关群 课余训练 “科技兴国” 运动生理 学校体育工作 理事长
下载PDF
Insulation fault diagnosis based on group grey relational grade analysis method for power transformers 被引量:5
8
作者 董立新 肖登明 刘奕路 《Journal of Southeast University(English Edition)》 EI CAS 2005年第2期175-179,共5页
Utilising dissolved gases analysis, a new insulation fault diagnosis methodfor power transformers is proposed. This method is based on the group grey relational grade analysismethod. First, according to the fault type... Utilising dissolved gases analysis, a new insulation fault diagnosis methodfor power transformers is proposed. This method is based on the group grey relational grade analysismethod. First, according to the fault type and grey reference sequence structure, some typicalfault samples are divided into several sets of grey reference sequences. These sets are structuredas one grey reference sequence group. Secondly, according to a new calculation method of the greyrelational coefficient, the individual relational coefficient and grade are computed. Then accordingto the given calculation method for the group grey relation grade, the group grey relational gradeis computed and the group grey relational grade matrix is structured. Finally, according to therelational sequence, the insulation fault is identified for power transformers. The results of alarge quantity of instant analyses show that the proposed method has higher diagnosis accuracy andreliability than the three-ratio method and the traditional grey relational method. It has goodclassified diagnosis ability and reliability. 展开更多
关键词 dissolved gases analysis group grey relational grade fault diagnosis
下载PDF
Correlation and Path Analysis for Growth Traits in F_1 Population of Pearl Oyster Pinctada martensii 被引量:34
9
作者 邓岳文 杜晓东 +2 位作者 王庆恒 符韶 黄荣莲 《Marine Science Bulletin》 CAS 2008年第2期68-73,共6页
120 pearl oysters (Pinctada martensii) were randomly sampled from F1 population, and shell length, shell width, shell height, shell weight and total weight of each sample were measured. Correlation and path analysis... 120 pearl oysters (Pinctada martensii) were randomly sampled from F1 population, and shell length, shell width, shell height, shell weight and total weight of each sample were measured. Correlation and path analysis were conducted on the basis of measurement data. The results showed that shell length, shell width, shell height, shell weight and total weight were significantly correlated (P 〈 0.05). Total weight was significantly and positively correlated with shell weight (r = 0.8970), shell height (r = 0.6974), shell width (r = 0.6521) and shell length (r = 0.5486). Shell weight, shell height, shell width and shell length had positive and direct effects on total wet weight, with the values of 0.6356, 0.1872, 0.1814 and 0.0599, respectively. The results indicated that growth traits (shell length, shell width, shell height, shell weight and total wet weigh) of the F1 population could be improved by direct or indirect selection. 展开更多
关键词 Pinctada martensii selected line F1 growth traits CORRELATION path analysis
下载PDF
Analysis of Genetic Variation and Population Structure of Starch Synthesis-related Genes in Indica Rice Cultivars
10
作者 赵春芳 胡庆峰 +7 位作者 强新涛 赵凌 赵庆勇 陈涛 周丽慧 姚姝 梁文化 王才林 《Agricultural Science & Technology》 CAS 2016年第9期1993-1999,共7页
In this study, 34 molecular markers of starch synthesis-related genes were used to evaluate the genetic variation and population structure of 87 indica rice cultivars from different countries and regions. The results ... In this study, 34 molecular markers of starch synthesis-related genes were used to evaluate the genetic variation and population structure of 87 indica rice cultivars from different countries and regions. The results showed that a total of 80 alleles were amplified using 34 primer pairs, with an average of 2.5 alleles per locus. The allele number varied from 2 to 6 among various cultivars. Shannon's diversity index of molecular markers varied from 0.303 to 0.796, with an average of 0.539. Polymorphism information content (PIC) varied from 0.084 to 0.658, with an average of 0.295. The genetic similarity coefficients of 87 indica rice cultivars ranged from 0.265 to 0.990, indicating significant genetic differences of starch synthesis-related genes among different cultivars, but the variation frequency of alleles varied among different cultivars. Population structure analysis showed that these 87 indica rice cultivars were divided into three categories. Genetic differences were small within the same category but great among different categories. Moreover, indica rice cultivars with simple genetic components accounted for 39.1% and those with complex genetic background accounted for 60.9%. This study may not only provide theoretical basis for genetic improvement of rice starch quality, but also lay a solid foundation for subsequent association analysis of rice quality-related traits. 展开更多
关键词 Indica rice Starch synthesis-related gene Genetic variation Population structure
下载PDF
Stock discrimination of spottedtail goby (Synechogobius ommaturus) in the Yellow Sea by analysis of otolith shape 被引量:7
11
作者 王英俊 叶振江 +1 位作者 刘群 曹亮 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2011年第1期192-198,共7页
Otolith shape is species specific and is an ideal marker of fish population affiliation. In this study, otolith shape of spottedtail goby Synechogobius ommaturus is used to identify stocks in different spawning locati... Otolith shape is species specific and is an ideal marker of fish population affiliation. In this study, otolith shape of spottedtail goby Synechogobius ommaturus is used to identify stocks in different spawning locations in the Yellow Sea. The main objectives of this study are to explore the potential existence of local stocks of spottedtail goby in the Yellow Sea by analysis of otolith shape, and to investigate ambient impacts on otolith shape. Spottedtail goby was sampled in five locations in the Yellow Sea in 2007 and 2008. Otoliths are described using variables correlated to size (otolith area, perimeter, length, width, and weight) and shape (rectangularity, circularity, and 20 Fourier harmonics). Only standardized otolith variables are used so that the effect of otolith size on the shape variables could be eliminated. There is no significant difference among variables of sex, year, and side (left and right). However, the otolith shapes of the spring stocks and the autumn stocks differ significantly. Otolith shape differences are greater among locations than between years. Correct classification rate of spottedtail goby with the otolith shape at different sampling locations range from 29.7%–77.4%. 展开更多
关键词 Synechogobius ommaturus the Yellow Sea otolith shape Fourier analysis
下载PDF
Plant community composition and interspecific relationships among dominant species on a post-seismic landslide in Hongchun Gully, China 被引量:6
12
作者 HUANG You-you HAN Han +1 位作者 TANG Chuan LIU Shou-jiang 《Journal of Mountain Science》 SCIE CSCD 2017年第10期1985-1994,共10页
The 5.12 Earthquake in 2008 and 8.14 Debris Flow in 2010 resulted in large-scale landslides that disturbed vast areas of vegetation in the Hongchun Gully, Wenchuan County, China. To define the specific characteristics... The 5.12 Earthquake in 2008 and 8.14 Debris Flow in 2010 resulted in large-scale landslides that disturbed vast areas of vegetation in the Hongchun Gully, Wenchuan County, China. To define the specific characteristics of vegetation restoration during natural recovery after catastrophic events,vegetation species composition and interspecific associations were investigated on this typical landslide. Field survey data selected from a total of 51 sample plots belonged to seven belt transects and were analysed by Schluter's variance ratio, pearson's chi-squared test, Spearman's correlation coefficients and ecological species groups. Plant communities on the landslide consisted of 78 species, 65 genera and52 families. Of the total of 78 species, 25 are identified as dominant species, among which Camptotheca acuminate, Toxicodendron vernicifluum, Coriaria nepalensis, Robinia pseudoacacia, Buddleja alternifolia, Anemone vitifolia and Nephrolepis auriculata play a constructive role during the natural afforestation. Moreover, according to environmental and ecological factors, these 25 dominant species could be divided into four ecological species groups.This study found that even though the landslide had frequently suffered from interference due to heavy rain, the vegetation succession processes are ongoing,and it is now at a shrub–herb community succession stage, which indicates that vegetation can naturally recover in the denuded sites. This study provides a useful insight into the ecological interactions and interdependence between plant species during the natural recovery of vegetation and provides valuable information on vegetation recovery modelling in the landslide area. 展开更多
关键词 Ecological rehabilitation Plant communities Vegetation recovery Geological hazard Hongchun Gully
下载PDF
Some Characterizations of Cryptogroups
13
作者 LIU Guo-xin ZHANG Jian-gang 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2006年第3期326-330,共5页
In this paper, we give some characterizations of(regular, normal) cryptogroups with Green's relations, left(right) translations and homomorphisms.
关键词 cryptogroup Green's relation TRANSLATION
下载PDF
Modeling heap biooxidation of arsenic-bearing gold ore 被引量:6
14
作者 LI Jia-feng ZHONG Shui-ping +3 位作者 TONG Lin-lin ZHANG Deng-chao BAO Dong-bin YANG Hong-ying 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第5期1424-1431,共8页
To design heap biooxidation process,it is necessary to understand its internal rules.The heap biooxidation of gold ore from Anhui province was researched in this study.The results showed that the main microorganisms i... To design heap biooxidation process,it is necessary to understand its internal rules.The heap biooxidation of gold ore from Anhui province was researched in this study.The results showed that the main microorganisms in the heap were A.ferrooxidans,F.acidiphilum and L.ferrodiazotrophum.Under their combined action,gold leaching extent rose from 35.62%to 78.08%in 80 d.Boltzmann model matches the actual oxidation effect better and the model equations were obtained.The model predicted that the oxidation extents of arsenic and sulfur are 58.577%and 42.122%after one year,and the gold leaching extent was 80.40%.The arsenic and sulfur oxidation extents,and gold leaching extent were all linearly correlated.It is more reliable to predict gold leaching extent by sulfur oxidation extent.These results provided good guidance for practical application in the actual production. 展开更多
关键词 heap biooxidation gold ore microbial community fitting CORRELATIVITY
下载PDF
Development of two microsatellite multiplex PCR systems for high throughput genotyping in Populus euphratica 被引量:1
15
作者 Eusemann Pascal Fehrenz Steffen Schnittler Martin 《Journal of Forestry Research》 SCIE CAS CSCD 2009年第A3期195-198,285,共5页
Eighteen microsatellite primer pairs previously developed at Oak Ridge National Laboratory for Populus tremuloides Michx. and Populus trichocarpa Torr. & Gray were screened for amplification in Euphrates poplar, P... Eighteen microsatellite primer pairs previously developed at Oak Ridge National Laboratory for Populus tremuloides Michx. and Populus trichocarpa Torr. & Gray were screened for amplification in Euphrates poplar, Populus euphratica Oliv. Thirteen loci were found to express polymorphisms ranging from two to 17 alleles. The eight most variable loci were selected to set up and optimize two multiplex polymerase chain reaction (PCR) assays. Three populations containing altogether 436 trees were used to characterize the selected loci and ascertain their applicability for parentage analysis and genotyping studies. Through cross-checking of clonal identity against sex of the genotyped trees we estimated the maximum error rate for merging genotypes to be less than 0.045. 展开更多
关键词 clone identification Euphrates poplar genetic fingerprint parentage analysis population structure SSR primers
下载PDF
Sem ilinear Equationswith CriticalExponentsonthe Heisenberg Group 被引量:1
16
作者 钮鹏程 文成林 《Chinese Quarterly Journal of Mathematics》 CSCD 1998年第3期52-58, ,共7页
We consider the semilinear subelliptic Laplace equation -Δ Hn u=u p+f(x,u) in Ω,u>0 in Ω,u=0 on Ω . Under suitable assumptions on f and p ,some existence and nonexistence results are obtained.
关键词 subelliptic Laplacian EXISTENCE EXPONENT
下载PDF
Statistical analysis of fracture properties based on particle swarm optimization and Pearson correlation coefficient method 被引量:4
17
作者 ZHOU Yin FENG Xuan +3 位作者 Enhedelihai LUO Teng YANG Xueting HE Mei 《Global Geology》 2015年第1期41-48,共8页
Prediction of reservoir fracture is the key to explore fracture-type reservoir. When a shear-wave propagates in anisotropic media containing fracture,it splits into two polarized shear waves: fast shear wave and slow ... Prediction of reservoir fracture is the key to explore fracture-type reservoir. When a shear-wave propagates in anisotropic media containing fracture,it splits into two polarized shear waves: fast shear wave and slow shear wave. The polarization and time delay of the fast and slow shear wave can be used to predict the azimuth and density of fracture. The current identification method of fracture azimuth and fracture density is cross-correlation method. It is assumed that fast and slow shear waves were symmetrical wavelets after completely separating,and use the most similar characteristics of wavelets to identify fracture azimuth and density,but in the experiment the identification is poor in accuracy. Pearson correlation coefficient method is one of the methods for separating the fast wave and slow wave. This method is faster in calculating speed and better in noise immunity and resolution compared with the traditional cross-correlation method. Pearson correlation coefficient method is a non-linear problem,particle swarm optimization( PSO) is a good nonlinear global optimization method which converges fast and is easy to implement. In this study,PSO is combined with the Pearson correlation coefficient method to achieve identifying fracture property and improve the computational efficiency. 展开更多
关键词 fracture property shear-wave splitting statistic analysis Pearson correlation coefficient particleswarm optimization
下载PDF
Development of the nano-composite cement:Application in regulating grouting in complex ground conditions 被引量:3
18
作者 WANG Sheng WANG Jing-fei +3 位作者 YUAN Chao-peng CHEN Li-yi XU Shi-tong GUO Kai-bin 《Journal of Mountain Science》 SCIE CSCD 2018年第7期1572-1584,共13页
Improvement of the fluidity and setting time of grouting materials has been recognized as an effective approach of seepage prevention in foundation works, and it is quite common to be used for handling severe leakages... Improvement of the fluidity and setting time of grouting materials has been recognized as an effective approach of seepage prevention in foundation works, and it is quite common to be used for handling severe leakages in complex ground conditions, such as loose, broken and fully fissured stratum. For the purposed of better meeting the engineering requirements, experimental studies were conducted in this study with focus on the nanocomposite grouting materials and the related controlled grouting technology. As compared with the commonly used silicate-sulpho-aluminate composite cement, which is characterized by relatively poor rheological property, quick setting time and low strength, the most suitable nano-material with proper reactants were selected intentionally to improve the mentioned attributes of composite cement. Due to the setting time and strength of the targeted cement slurry behaving with poor performance of harmonization to engineering construction problems, hydration synergistic effect of these composites were investigated in our experiments. Results showed that the properties of grouting materials, including initial fluidity, setting time, ideal right-angle thickening, and early strength and late strength were sufficient to produce an expected grouting application. It is therefore advocated that the refined grouting material could provide a better solution to fix grouting problems in complex ground cementing operations. 展开更多
关键词 NANO-SILICA Silicate-sulpho-aluminate composite cement grout Controlled grouting Complex ground conditions
下载PDF
Automatic relational database compression scheme design based on swarm evolution 被引量:1
19
作者 HU Tian-lei CHEN Gang +1 位作者 LI Xiao-yan DONG Jin-xiang 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第10期1642-1651,共10页
Compression is an intuitive way to boost the performance of a database system. However, compared with other physical database design techniques, compression consumes large amount of CPU power. There is a trade-off bet... Compression is an intuitive way to boost the performance of a database system. However, compared with other physical database design techniques, compression consumes large amount of CPU power. There is a trade-off between the re- duction of disk access and the overhead of CPU processing. Automatic design and adaptive administration of database systems are widely demanded, and the automatic selection of compression schema to compromise the trade-off is very important. In this paper, we present a model with novel techniques to integrate a rapidly convergent agent-based evolution framework, i.e. the SWAF (SWarm Algorithm Framework), into adaptive attribute compression for relational database. The model evolutionally consults statistics of CPU load and IO bandwidth to select compression schemas considering both aspects of the trade-off. We have im- plemented a prototype model on Oscar RDBMS with experiments highlighting the correctness and efficiency of our techniques. 展开更多
关键词 Database compression Automatic physical database design Swarm evolution
下载PDF
The Relationship of Between Fuzzy Power Groups and Fuzzy Quotient Groups
20
作者 YAN Guang-xia MI Hong-hai SHI Ya-ting 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2006年第4期493-496,共4页
In this paper, we extend the concept of fuzzy quotient groups. The structuresof fuzzy power groups and fuzzy quotient groups are discussed. The relationship betweenfuzzy power groups and fuzzy quotient groups are cons... In this paper, we extend the concept of fuzzy quotient groups. The structuresof fuzzy power groups and fuzzy quotient groups are discussed. The relationship betweenfuzzy power groups and fuzzy quotient groups are considered. 展开更多
关键词 GROUP power group UPGRADE fuzzy power group mathematics structure
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部