检索结果-南通市图书馆

Province-scale commonalities of some world-class gold deposits:implications for mineral exploration

Geoscience Frontiers 2015年第3期6卷 389-399页

作者： David i.Groves m.Santosh Centre for Exploration Targeting UWA State Key Laboratory of Geological Processes and mineral Resources China University of Geosciences Centre for Tectonics Resources and Exploration Dept.of Earth SciencesUniversity of Adelaide Division of interdisciplinary Science Faculty of ScienceKochi University

Discovery rates for all metals, including gold, are declining, the cost per significant discovery is increasing sharply, and the economic situation of the industry is one of low base rate. The current hierarchical structure of the exploration and mining industry makes this situation difficult to redress. Economic geologists can do little to influence the required changes to the overall structure and philosophy of an industry driven by business rather than geological principles, However, it should be possible to follow the lead of the oil industry and improve the success rate of greenfield exploration, necessary for the next group of lower-exploration-spend significant mineral deposit discoveries. Here we promote the concept that mineral explorers need to carefully consider the scale at which their exploration targets are viewed. it is necessary to carefully assess the potential of drill targets in terms of terrane to province to district scale, rather than deposit scale, where most current economic geology research and conceptual thinking is concentrated. if orogenic, iRGD, Carlin-style and iOCG gold-rich systems are viewed at the deposit scale, they appear quite different in terms of conventionally adop- ted research parameters. However, recent models for these deposit styles show increasingly similar source-region parameters when viewed at the lithosphere scale, suggesting common tectonic settings. it is only by assessing individual targets in their tectonic context that they can be more reliably ranked in terms of potential to provide a significant drill discovery. Targets adjacent to craton margins, other lithosphere boundaries, and suture zones are clearly favoured for all of these gold deposit styles, and such exploration could lead to incidental discovery of major deposits of other metals sited along the same tectonic boundaries.

关键词： mineral exploration Gold deposits Tectonic settings mining industry Discovery rate

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Computer modelling of metal Dissolution in the Presence of Aqueous Electrolyte

引用

Chinese Physics Letters 2002年第3期19卷 389-390页

作者： R.i.Eglitis m.R.Philpott UniversitatOsnabruck FachbereichPhysikD-49069OsnabruckGermany DepartmentofmaterialsScience NationalUniversityofSingapore10KentRidgeCrescentSingapore119260

The semi-empirical Hartree-Fock intermediate neglect of differential overlap (iNDO) method was used to explore the potential energy surface of adsorbed water molecules and to speculate, using fairly simple cluster models, on the reaction path followed by metal ions leaving the surface. As an example, iNDO calculations were used to calculate the potential energy curve for a metal atom leaving the surface and entering into a solvation cage composed of tetrahedral arranged water molecules. The effect of adding a NaCl ion pair to the system with the halide ion above the dissolving atom was also explored.

关键词： metals

来源：

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

Peculiarity of magnetoresistance of discontinuous ferromagnetic thin films

引用

international Journal of minerals,metallurgy and materials 2017年第12期24卷 1459-1463页

作者： Yu.O. Shkurdoda i.m. Pazukha A.m. Chornous Department of Applied Physics Sumy State UniversitySumy 40007Ukraine

The magnetoresistive properties of discontinuous ferromagnetic Fe and Co thin films deposited by electron-beam sputtering onto glass substrates at room temperature were investigated. Tunnel magnetoresistance(mR) was observed for all of the as-deposited samples. The maximum mR was observed for Fe thin films with an effective thickness of 17 nm. in the case of the Co thin films, the annealing process led to a change of the type of mR to anisotropic at Co film thicknesses(dCo) of 15 ≤ d_(Co) ≤ 25 nm and to positive isotropic at thicknesses of d_(Co) m. By contrast, the mR type of Fe thin films did not change.

关键词： discontinuous thin films ferromagnetic structure magnetoresistance peculiarity

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The performance of activated carbon/NiFe_(2)O_(4) magnetic composite to retain heavy metal ions from aqueous solution

引用

Chinese Journal of Chemical Engineering 2021年第1期34卷 135-145页

作者： S.i.moussa m.m.S.Ali Reda R.Sheha Nuclear Chem.Dept. Hot Lab CenterAtomic Energy AuthorityCairo 13759Egypt Analytical Chem.Dept. Hot Lab CenterAtomic Energy AuthorityCairo 13759Egypt

A novel magnetic activated carbon composite(AC/NiF) was synthesized by a precipitation method and applied in retention of Cu(Ⅱ),and Zn(Ⅱ) ions from aqueous *** impact of different sorption parameters such as:equilibration time,solution pH value,competing cations and ionic strength on the amount sorbed of Cu(Ⅱ),and Zn(Ⅱ) was *** illustrated that the magnetic composite had retention ability towards both metal ions significantly higher than that of activated carbon(AC).The magnetic composite exhibited an affinity to adsorb Cu(Ⅱ) higher than Zn(Ⅱ) *** maximum sorption capacities(Q_(max)) of the applied magnetic composite(AC/NiF)towards Cu(Ⅱ) and Zn(Ⅱ) were 105.8 and 75.1 mg·g^(-1),*** of Cu(Ⅱ) and Zn(Ⅱ) was proposed to be achieved though an ion exchange and surface adsorption in neutral conditions,while precipitation was believed to be the relevant mechanism in their removal from basic *** kinetic studies showed that sorption process followed the kinetics of pseudo-second-order reactions with rate constant of 3 × 10^(-3) and 2 × 10^(-3) min^(-1)for sorption of Cu(Ⅱ) and Zn(Ⅱ) onto AC/NiF *** of Cu(Ⅱ) slightly decreased with increasing the ionic strength of aqueous solution,using NaCl as a background *** contrast,presence of mn(Ⅱ),mg(Ⅱ)and Co(Ⅱ) in reaction solutions highly depressed the sorption of Cu(Ⅱ) and Zn(Ⅱ) with a competing efficiency followed the order:mg(Ⅱ)> mn(Ⅱ)> Co(Ⅱ).The magnetic composite was rapidly recovered from aqueous solution by an external magnetic field,and effectively regenerated using 0.1 mol L^(-1) HCl and 0.1 mol L^(-1) FeCl_(3) as *** of Cu(Ⅱ) and Zn(Ⅱ) onto the surface of AC/NiF composite occurred via a spontaneous *** thermodynamically favorable process had ΔH~o values of 30.9 kJ·mol^(-1) and 19.7 kJ·mol^(-1),*** results confirm that the magnetic composite can be viewed as a promising novel composite opens new opportunities f

关键词： Activated carbon Nickel ferrite Composite mechanism

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Physical and Dielectric Properties of Some Nonionic Surfactants

引用

Journal of materials Science & Technology 1998年第4期14卷 361-367页

作者： El-Anwar, i.m. El-Henawii, S.A. National Research Center Dokki Cairo Egypt Faculty of Science Helwan University Egypt

Fatty acid esters have been prepared by reacting the acid C//1//8 with polyethylene glycols having varying numbers of oxyethylene units (4-88 units) by the direct esterification reaction method. Surface and interfacial tensions were studied at various experimental conditions, including, concentration, temperature and chemical constitution of the surfactant. Critical micelle concentrations (CmC), surface excess and residual area occupied by each surface active agent molecule A have been calculated by using Gibb's equations. CmC values range from 10 to 55 multiplied by 10** minus **5 mole/L for all studied agents, while the residual area occupied by each molecule varies from 0.6 to 1.5 nm**2. Variation of CmC of some of these agents with temperature have been also examined and the obtained data were used to calculate the heat of micellization delta H//m and the entropy change during micellization delta S//m. Values of delta H//m vary from 14.63 kJ/mole to 2.717 kJ/mole depending on the chemical constitution of the agent under consideration. The apparent dipole moments mu of three surfactant were measured following the Headstrand's method. (Edited author abstract) 23 Refs.

关键词： Surface active agents

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Corrosion of AiSi 4130 Steel Alloy under Hydrodynamic Condition in Ethylene Glycol+Water+NO_2^- Solution

引用

Journal of materials Science & Technology 2013年第1期29卷 89-96页

作者： i.Danaee m.Niknejad Khomami A.A.Attar Abadan Faculty of Petroleum Engineering Petroleum University of Technology

The electrochemical behavior of steel alloy in ethylene glycol-water mixture at different solution rotating speeds was investigated by polarization curves and AC impedance measurements （EiS）. The results obtained showed that corrosion rate was not changed significantly at different rotating speeds and was decreased with increasing ethylene glycol concentration. The effect of nitrite as an inhibitor was studied and high inhibition efficiency was obtained. it was found that surface passivation occurred in the presence of inhibitor. The inhibiting effect of the nitrite was explained on the basis of the competitive adsorption between the inorganic anions and the aggressive Ci- ions and the adsorption isotherm basically obeys the Flory-Huggins adsorption isotherm. Thermodynamic parameters for steel corrosion and inhibitor adsorption were determined, which revealed that the adsorption process is spontaneous.

关键词： Steel 4130 Ethylene glycol Corrosion Hydrodynamic Nitrite

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Corrosion behavior of magnesium and magnesium alloys

引用

中国有色金属学会会刊：英文版 2004年第1期14卷 1-10页

作者： i.m.Baghni 吴荫顺李久青张巍 mechanical Engineering Department Engineering College Tajoura Libya Corrosion & Protection Center University of Science and Technology Beijing Beijing 100083 China

The automotive industry has crossed the threshold from using magnesium alloys in interior applications such as instrument panels and steering wheels to unprotected environment such as oil pan, cylinder head and wheels. The expanding territory of magnesium leads to new challenges: mainly environmental degradation of the alloys used and how they can be protected. The present critical review is aimed at understanding the corrosion behavior of magnesium and magnesium alloys in industrial and marine environments, and the effect of microstructure, additive elements and inhibitors on the corrosion mechanism.

关键词：镁镁合金腐蚀显微结构汽车工业

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Bianchi type i in f(T) gravitational theories

引用

Chinese Physics B 2016年第5期25卷 58-64页

作者： m i Wanas G G L Nashed O A ibrahim Astronomy Department Faculty of Science Cairo University Cairo Egypt Centre for Theoretical Physics The British University in Egypt El-Sherouk City Egypt mathematics Department Faculty of Science Ain Shams University Cairo Egypt Egyptian Relativity Group (ERG) Giza Egypt

A tetrad field that is homogeneous and anisotropic which contains two unknown functions A（t） and B（t） of cosmic time is applied to the field equations of f（T）, where T is the torsion scalar, T = T~μ_（νρ）S_μ^（νρ）. We calculate the equation of continuity and rewrite it as a product of two brackets, the first is a function of f（T） and the second is a function of the two unknowns A（t） and B（t）. We use two different relations between the two unknown functions A（t） and B（t） in the second bracket to solve it. Both of these relations give constant scalar torsion and solutions coincide with the de Sitter one. So,another assumption related to the contents of the matter fields is postulated. This assumption enables us to drive a solution with a non-constant value of the scalar torsion and a form of f（T） which represents ΛCDm.

关键词： f(T) gravitational theory Bianchi type i special solutions

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The extended cubic B-spline algorithm for a modified regularized long wave equation

引用

Chinese Physics B 2013年第4期22卷 75-80页

作者： i.Dag D.irk m.Sari Faculty of Science and Arts Department of Mathematics and Computer Sciences Eskis ehir Osmangazi niversitesi Eskis ehir Turkey Faculty of Science and Arts Department of Mathematics Pamukkale niversitesi Denizli Turkey

A collocation method based on an extended cubic B-spline function is introduced for the numerical solution of the modified regularized long wave equation. The accuracy of the method is illustrated by studying the single solitary wave propagation and the interaction of two solitary waves of the modified regularized long wave equation.

关键词： collocation methods solitary waves

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Finding Dirac Spin Effect in NUT Spacetime

引用

Communications in Theoretical Physics 2010年第5期53卷 864-868页

作者： m.Korunur m.Salti i.Acikgoz Department of Physics Faculty of Art and Science Dicle University

in the present study, we are interested in finding the spin precession of a Dirac particle in expanding and rotating NUT spaeetime. A tetrad with two functions to be determined is applied to the field equation of the teleparallel theory of gravity via a coordinate transformation. The vector, the axial-vector and the tensor parts of the torsion tensor are obtained. We found that the vector parts are in the radial and Ф-directions. The axial-vector torsion is along r-direction while its other components along θ and oh-directions vanish everywhere. The vector connected with Dirac spin has been evaluated as well.

关键词： NUT spacetime axial-vector torsion Dirac particle

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：