检索结果-南通市图书馆

Science China Earth Sciences 2000年第6期43卷 569-576页

作者：刘再华袁道先何师意张美良张加桂 Institute of Karst Geology Ministry of Land and Resources Guilin 541004 China Institute of Environmental Geology Ministry of Land and Resources Beijing 100081 China

Taking Huanglong Ravine and Kangding, Sichuan, and Xiage, Zhongdian, Yunnan, as examples, the authors summarize the hydrogeochemical and carbon stable isotopic features of the geothermal CO2-water-carbonate rock system and analyze the CO2 sources of the system. It was found that the hydrogeochemical and carbon stable isotopic features of such a system are different from those of shallow CO2-water-carbonate rock system, which is strongly influenced by biosphere. The former has higher CO2 partial pressure, and is rich in heavy carbon stable isotope. In addition, such a geothermal system is also different from that developed in igneous rock. The water in the latter system lacks Ca2+, and thus, there are few tufa deposits on ground surface, but it is rich in light carbon stable isotope. Further analysis shows that CO2 of the geothermal CO2-water-carbon-ate rock system is a mixture of metamorphic CO2 and magmatic CO2.

关键词： geothermal CO2-water-carbonate rock system hydrogeochemistry carbon stable isotope CO2 sources.

The possible source of uranium mineralization in felsic volcanic rocks,Eastern Desert,Egypt of the Arabian-Nubian Shield:Constraints from whole-rock geochemistry and spectrometric prospection

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2021年第5期40卷 819-845页

作者： Gehad.M.Saleh Bahaa.M.Emad Ibrahim.B.Abdel Kader Rania.M.Sakr Nuclear Materials authority El MaadiP.O.Box 530CairoEgypt

The present work deals with the detailed geology,mineralogy,geochemistry,and spectrometric prospection of the felsic volcanic rocks at the Eastern Desert,Egypt of the Arabian-Nubian *** volcanic rocks are an essential source for rare earth elements(REEs)and uranium occurrences in this *** are compositionally uniform with tholeiitic to calc-alkaline affinities,peraluminous and belong to the series of rhyolite with high-K *** exhibit more enrichment in high field strength elements(HFSE,***,Ta,Nd,Th,and U)and large-ion lithophile elements(LILE,*** and Rb)compared to the country rocks of the studied area,with REE ranging from 188.20 to 442.70 ppm and strong depletion in Ti,Sr,P with deep negative Eu *** felsic volcanic rocks were mostly generated from the partial melting of quartz-amphibolite facies accreted during the *** oddities of Zr-U-Th for the felsic volcanic rocks determine the involvement of crustal *** volcanic rocks are found in A-type suites of magma and represent highly fractionated rocks derived from rhyolitic magma,with insignificant interaction with continental crust in the low-pressure environment and during fractional *** volcanic rocks have higher values of radioactivity in which eU range from 0.5 to 121 ppm and eTh from 1.0 to 415.10 *** high values of eU and eTh can be ascribed to the mineralization of uranium and the presence of accessory minerals of radiogenic nature such as uranophane,uranothorite,zircon,and *** is considered as the mineral with most enriched uranium contents in the studied felsic volcanic rocks in which(UO2=87.30 wt%).Also,they are enriched with REE-bearing accessory minerals comprising allanite,titanite,and *** geological investigations of the felsic volcanic rocks in the studied areas are inappropriate to clear the feasible economic potentialities of rare earth elements and U occurrences;itemized and invaluable

关键词： Felsic volcanic rocks Geochemistry REE Uranium mineralization Egypt Arabian-Nubian Shield

Spatial Interpolation of Soil Texture Using Compositional Kriging and Regression Kriging with Consideration of the Characteristics of Compositional Data and Environment Variables

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2013年第9期12卷 1673-1683页

作者： ZHANG Shi-wen SHEN Chong-yang CHEN Xiao-yang YE Hui-chun HUANG Yuan-fang LAI Shuang China Agricultural University/Key Laboratory of Arable land Conservation (North China) Minstry of Agriculture/Key Laboratory of Agricultural Land Quality MonitoringMinistry of Land and Resources School of Earth and Environment Anhui University of Science and Technology Afforestation Management Office Sichuan Forestry Department

The spatial interpolation for soil texture does not necessarily satisfy the constant sum and nonnegativity constraints. Meanwhile, although numeric and categorical variables have been used as auxiliary variables to improve prediction accuracy of soil attributes such as soil organic matter, they （especially the categorical variables） are rarely used in spatial prediction of soil texture. The objective of our study was to comparing the performance of the methods for spatial prediction of soil texture with consideration of the characteristics of compositional data and auxiliary variables. These methods include the ordinary kriging with the symmetry logratio transform, regression kriging with the symmetry logratio transform, and compositional kriging （CK） approaches. The root mean squared error （RMSE）, the relative improvement value of RMSE and Aitchison＇s distance （DA） were all utilized to assess the accuracy of prediction and the mean squared deviation ratio was used to evaluate the goodness of fit of the theoretical estimate of error. The results showed that the prediction methods utilized in this paper could enable interpolation results of soil texture to satisfy the constant sum and nonnegativity constraints. Prediction accuracy and model fitting effect of the CK approach were better, suggesting that the CK method was more appropriate for predicting soil texture. The CK method is directly interpolated on soil texture, which ensures that it is optimal unbiased estimator. If the environment variables are appropriately selected as auxiliary variables, spatial variability of soil texture can be predicted reasonably and accordingly the predicted results will be satisfied.

关键词： compositional kriging auxiliary variables regression kriging symmetry logratio transform

Discrete logistics network design model under interval hierarchical OD demand based on interval genetic algorithm

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2013年第9期20卷 2625-2634页

作者：李利华符卓周和平胡正东 School of Traffic and transport Engineering Changsha University of Science and Technology School of Traffic and transport Engineering Central South University School of Politics and Public Administration University of South China

Aimed at the uncertain characteristics of discrete logistics network design,an interval hierarchical triangular uncertain OD demand model based on interval demand and network flow is *** consideration of the system profit,the uncertain demand of logistics network is measured by interval variables and interval parameters,and an interval planning model of discrete logistics network is *** risk coefficient and maximum constrained deviation are defined to realize the certain transformation of the *** integrating interval algorithm and genetic algorithm,an interval hierarchical optimal genetic algorithm is proposed to solve the *** is shown by a tested example that in the same scenario condition an interval solution[3275.3,3 603.7]can be obtained by the model and algorithm which is obviously better than the single precise optimal solution by stochastic or fuzzy algorithm,so it can be reflected that the model and algorithm have more stronger operability and the solution result has superiority to scenario decision.

关键词： uncertainty interval planning hierarchical OD logistics network design genetic algorithm

Spectral Features of Soil Organic Matter

在线全文

学校读者我要写书评

暂无评论

Geo-Spatial Information Science 2009年第1期12卷 33-40页

作者： HE Ting WANG Jing LIN Zongjian CHENG Ye Key Laboratory of land Use Ministry of Land and Resources 37 Guanyin~uanxiqu Xicheng District Beijing lO0035China.

The study on soil spectral reflectance features is the physical basis for soil remote sensing. Soil organic matter content influences the soil spectral reflectance dramatically. This paper studied the spectral curves between 400 nm-2500 nm of 174 soil samples which were collected in Hengshan county and Yixing county. Fourteen types of transformations were applied to the soil reflectance R to remove the noise and to linearize the correlation between reflectance （independent vari- able） and soil organic matter （SOM） content （dependent variable）. Then, the methods such as derivative spectrum technology and stepwise regression analysis, were applied to study the relationship between these soil spectral features and soil organic matter content. It shows that order 1 derivative of the logarithm of reflectance （01DLA） is the most sensitive to SOM among the various transform types of reflectance in consideration. The regression model whose coefficient of determination reaches 0.885 is built. It predicted the soil organic matter content with higher effect.

关键词： soil organic matter (SOM) spectral features stepwise regression analysis

Petrogenesis,Geodynamics and Radioactivity of the Granitic Rocks of the Nugrus Weakness Zone,South Eastern Desert,Egypt

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 Geologica Sinica(English Edition) 2021年第4期95卷 1183-1198页

作者： Soliman ABU ELATTA Abdallah Mahmoud Gehad M.R.MANSOUR Nuclear Materials authority CairoEgypt.P.O.Box 530 El Maadi

The studied granitic bodies belong to the south Eastern Desert of *** extend in a NNW–SSE trend along the same strike of the Nugrus weakness zone by which they are structurally *** rocks are composed of biotite and biotite-muscovite monzogranites to ***,a higher abundance of Ba and Rb in biotite granites with a relatively low abundance in biotite-muscovite granites as well as the diversity of Th,U,Nb,Ta,Zr,and REE reflects their origin from different sources and geodynamic *** biotite granites are predominantly metaluminous to low peraluminous whereas the biotite-muscovite granites have a peraluminous *** enrichment at the expense of calcium in these rocks reflects a derivation from crustal sources by partial melting in the presence of a volatile *** investigation showed high abundances of U(up to 38 ppm)and Th(up to 26 ppm)in biotite-muscovite granites relative to biotite granites(up to 5 ppm U and 18 ppm Th).Radioactive anomalies furthermore have been recorded in parts of biotite-muscovite granites that were affected by the faults(up to 116 ppm eU and 97 ppm eTh).Consequently,biotite-muscovite granites form a potentially fertile source for uranium mineralization.

关键词： partial melting biotite-muscovite granites peraluminous geodynamic radioactivity Nugrus

Yttria Tetragonal Zirconia Biomaterials:Kinetic Investigation

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2011年第4期27卷 332-337页

作者： Ezzat S.Elshazly S.M.El-Hout M.El-Sayed Ali Department of Mechanical Engineering Virginia Commonwealth University Deptartment of Metallurgy Nuclear Research CenterAtomic Energy Authority

The low temperature aging behavior of polycrystalline tetragonal zirconia was investigated to explore the effects on phase transformation occurring during the process. XRD analysis was conducted for the phase identification and the tetragonal to monoclinic phase transformation was determined. The aging of tetragonal zirconia polycrystals doped with 3 mol% Y203 triggers tetragonal to monoclinic phase transformation on the surface of the specimen only, while the penetration inside the bulk of the specimen is very limited. A slight decrease in the mechanical properties was also observed after aging for 40 h. The transformation kinetics show a nucleation and growth mechanism on the specimen surface to be dominant in the low temperature aging in water environment.

关键词： Low temperature degradation 3Y-TZP Kinetics

Ra's Abdah of the north Eastern Desert of Egypt:the role of granitic dykes in the formation of radioactive mineralization,evidenced by zircon morphology and chemistry

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2016年第4期35卷 368-380页

作者： Ali A.Omran Osama K.Dessouky Nuclear Materials authority P.O.Box 530El MaadiCairoEgypt

Syenogranitic dykes in the north of Egypt's Eastern Desert are of geological and economic interest because of the presence of magmatic and supergene enrichment of radioactive mineralization. Zircon crystal morphology within the syenogranitic dykes allows precise definition of sub-alkaline series granites and crystallized at mean temperature of about 637 °C. The growth pattern of the zircons suggest magmatic and hydrothermal origins of radioactive mineralization. Hydrothermal processes are responsible for the formation of significant zircon overgrowth; high U-zircon margins might have occurred contemporaneously with the emplacement of syenogranitic dykes which show anomalous uranium(e U) and thorium(e Th) contents of up to 1386 and 7330 ppm, *** chemistry revealed a relative increase of Hf consistent with decreasing Zr content, suggesting the replacement of Zr by Hf during hydrothermal *** uranium mineralization is present and recognized by the presence of uranophane and autunite.

关键词： Syenogranitic dykes Zircon Morphology Typology Uranium Egypt

Finding an optimization of the plate element of Egyptian research reactor using genetic algorithm

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2008年第5期19卷 314-320页

作者： WAHED Mohamed IBRAHIM Wesam EFFAT Ahmed Mathematics Department Faculty of ScienceZagazic UniversityEgypt Atomic Energy authority CairoEgypt

The second Egyptian research reactor ET-RR-2 went critical on the 27th of November *** National Center of Nuclear Safety and Radiation Control (NCNSRC) has the responsibility of the evaluation and assessment of the safety of this *** purpose of this paper is to present an approach to optimization of the fuel element plate. For an efficient search through the solution space we use a multi objective genetic algorithm which allows us to identify a set of Pareto optimal solutions providing the decision maker with the complete spectrum of optimal solutions with respect to the various *** aim of this paper is to propose a new approach for optimizing the fuel element plate in the *** fuel element plate is designed with a view to improve reliability and lifetime and it is one of the most important elements during the shut *** this present paper,we present a conceptual design approach for fuel element plate,in conjunction with a genetic algorithm to obtain a fuel plate that maximizes a fitness value to optimize the safety design of the fuel plate.

关键词：埃及核反应堆遗传算法燃料元件核技术

Detailing Losses in the M/M/1/1 Transient Loss System

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2018年第2期34卷 373-385页

作者： Pierpaolo FERRANTE National Workers Compensation authority (INAIL) Department of Occupational and Environmental Medicine Epidemiology and Hygiene (DiMEILA)

This paper is aimed at investigating the transient losses in the M/M/1/1 Erlang loss system. We evaluate the explicit form of the probability distribution of the number of losses in the time interval [0, t） and provide two alternative representations： one based on the iterated derivatives of hyperbolic sinus and cosine and the other on the spherical modified Bessel function of the second kind. The mathematical structures of the transient loss rate and of the transient probability of losing all customers are described and several analytical properties are derived.

关键词： transient losses transient loss rate Erlang bessel functions