检索结果-南通市图书馆

The gold-telluride connection:Evidence for multiple fluid pulses in the Jinqingding telluride-rich gold deposit of Jiaodong Peninsula,Eastern China

引用

Geoscience Frontiers 2024年第3期15卷 146-165页

作者： Wenyan Cai Mingchun Song M.Santosh jian Li School of Resources and Environmental Engineering Shandong University of TechnologyZibo 255049China Hebei Key Laboratory of Strategic Critical Mineral Resources Hebei GEO UniversityShijiazhuang 050031China School of Earth Sciences and Resources China University of Geosciences Beijing29 Xueyuan RoadBeijing 100083China Department of Earth Science University of AdelaideAdelaide SA 5005Australia

The mechanism of gold migration,enrichment,and precipitation in forming world-class gold deposits has been a topic of wide interest,particularly where these deposits are abundant in *** Jiaodong Peninsula in eastern China hosts some of the world-class gold deposits among which the Jinqingding deposit is one of the best examples with substantial telluride mineralization and thus provides opportunity to investigate the genetic connection between tellurium and gold *** orebody in this deposit is hosted in the NE-NNE-trending jiangjunshi-Quhezhuang fault with the Jurassic Kunyushan granitic pluton as wall *** deposit involved three mineralization stages as inferred from assemblages and crosscutting relationships between *** stages are:(I)pre-ore gold-poor quartz-pyrite veins,(II)main ore auriferous quartz-pyrite-Te/Bi-minerals±sphalerite±chalcopyrite±barite±marcasite veins,and(III)post-ore quartz-calcite *** present here the textural,isotopic,and geochemical variations of different stages/generations of pyrite based on scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS),electron probe microanalysis(EPMA),and laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS).Pyrite in the Jinqingding deposit displays distinct ***1a shows a porous and dissolution-reprecipitation texture in the core,whereas Py1b exhibits a smooth and flat *** analysis reveals contrasting elemental compositions,with Py1a characterized by low Au(avg.0.14 ppm),As(avg.15.57 ppm),Ag(avg.17.71 ppm),and Te(avg.19.2. ppm)contents,but elevated Co(avg.1068.10 ppm)and Ni(2.4.12.ppm)concentrations,and variable sulfur isotopic composition(δ^(34)SV-CDT=9.54‰-12.12.).Conversely,Py1b displays increased concentrations of these elements and a more concentratedδ^(34)SV-CDT value(11.99‰-12.2.‰),possibly associated with weak coupled dissolution-reprecipitation(CDR)*** Stage II,pyrite can be further categorized

关键词： Episodic fluid pulses Sulfur reservoir Gold-Te precipitation Jinqingding deposit Jiaodong Peninsula

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

Block dual Toeplitz Operators on the Orthogonal Complements of Fock Spaces

引用

Acta Mathematica Sinica,English Series 2024年第8期40卷 1967-1988页

作者： jian Xiang DONG Chun Xu XU Yu Feng LU School of Mathematical Sciences Dalian University of TechnologyDalian 116024P.R.China School of Mathematics and Information Science Guangzhou UniversityGuangzhou 510006P.R.China

In this paper,we characterize the boundedness and compactness of the block dual Toeplitz operators acting on the orthogonal complement of the Fock spaces,and the compactness of the finite sum of two dual Toeplitz oper... 详细信息

关键词： Block dual Toeplitz operators boundedness compactness Fock space (semi)-commutator

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

Occurrence and possible sources of antibiotic resistance genes in seawater of the South China Sea

引用

Frontiers of Environmental Science & Engineering 2024年第9期18卷 27-38页

作者： jian Lu Jun Wu Cui Zhang jianhua Wang Xia He CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation Yantai Institute of Coastal Zone Research(YIC)Chinese Academy of Sciences(CAS)Shandong Key Laboratory of Coastal Environmental ProcessesYICCASYantai 264003China Yantai Research Institute Harbin Engineering UniversityYantai 264006China College of Environmental Science and Engineering Guilin University of TechnologyGuilin 541006China

Antibiotic resistance genes(ARGs)might have great effect on ecological security and human *** are important reservoirs that receive tremendous amounts of pollutants ***,information on the proliferation of ARGs in seawater is still *** study performed field sampling to investigate the occurrence and distribution of ARGs in seawater of the South China Sea,which is the deepest and largest sea in *** results showed that the total absolute abundances of ARGs in seawater samples ranged from 2.1×10^(3)to 2.3×10^(4)copies/mL,with an of 5.0×10^(3)copies/mL and a range of 2.2.10^(3)–1.8×10^(4)copies/mL for those with mobile genetic elements(MGEs).Genes resistant to multidrug,aminoglycoside,tetracycline,and fluoroquinolone antibiotics accounted for 77.3%–88.6%of total ARGs in *** and Cyanobacteria represented 32.1%–56.2.and 30.4%–49.5%of microbial community,***_MIT9313 and Clade_la were the prevalent genera in seawater of the South China *** co-occurrence relationship existed among ARGs,MGEs,and *** activities had critical influence on ARGs and *** wastewater,wastewater treatment plant effluent,sewage,aquaculture tailwater,and runoff were determined as the important sources of ARGs in seawater of the South China Sea based on positive matrix factorization analysis.

关键词： The South China Sea Antibiotic resistance genes Mobile genetic element Source apportionment

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

Comprehensive tensile properties improved by deep cryogenic treatment prior to aging in friction-stir-welded 2.98 Al–Li alloy

引用

Rare Metals 2024年第10期43卷 5403-5409页

作者： jian-Qiu Sun Yue Ma Chong Gao Hong-Yun Luo School of Materials Science and Engineering Beihang University Chinalco Research Institute of Science and Technology

In order to improve the comprehensive mechanical properties,deep cryogenic treatment （DCT）prior to aging was carried out on friction-stir-welded（FSW） 2.98 Al-Li alloy;afterward,the microstructure and tensile properties were characterized by means of optical microscopy （OM）,transmission electron microscopy（TEM） and tensile *** results show that FSW 2.98 alloy through DCT prior to aging （DAT） possesses superior tensile properties than conventional aging treatment （AT）The microstructural analysis reveals that DAT alloy exhibits a finer grain structure,since DCT might effectively alleviate the residual stress in FSW 2.98 alloy and thus decrease the driving force for grain coarsening in subsequent aging ***,DCT generates dislocation multiplication,which provides more preferential nucleation sites for T1 （Al2.uLi） phase during subsequent aging treatment,resulting in high-density fine T1 phases and thin precipitate-free zone within DAT *** reasonable microstructure leads to DAT alloy possessing better strength-ductility combination compared to AT alloy.

关键词： Al–Li alloy Deep cryogenic treatment Friction stir welding Tensile properties

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress of vegetation modelling and future research prospects

引用

Science China Earth Sciences 2024年第9期67卷 2718-2738页

作者： Siqi LI Xu ZHANG Zhengyao LU jian NI jianhua LU State Key Laboratory of Tibetan Plateau Earth System Resources and Environment(TPESRE)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China British Antarctic Survey Cambridge CB30ETUnited Kingdom Department of Physical Geography and Ecosystem Science Lund UniversityLund 22362Sweden College of Life Sciences Zhejiang Normal UniversityJinhua 321004China School of Atmospheric Sciences Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China

Terrestrial vegetation is a crucial component of the Earth system,and its changes not only represent one of the most distinct aspects of climate change but also exert significant feedback within the climate system by exchanging energy,moisture,and carbon *** quantitatively and mechanistically study climate-vegetation feedback,numerical vegetation models have been developed on the theory of ecophysiological constraints on plant functional *** models eventually can simulate vegetation distribution and succession across different spatial and temporal scales,and associated terrestrial carbon cycle processes by categorizing vegetation into biomes according different plant functional types and their associated environmental *** we review the developing history of vegetation models and provide recent advances and future *** 2.st century,static vegetation models,as developed statistical models,can only simulate equilibrated characteristics of vegetation *** last several decades,Dynamic Global Vegetation Models(DGVMs)have been developed to simulate instantaneous responses of vegetation to climate change and associated dynamics,and can be coupled with Earth system models to investigate interactions among atmosphere,ocean,and *** are also widely applied to investigate the dynamics accounting for changes in the geographic distribution patterns of land surface vegetation at different spatial and temporal scales and to assess the impacts of terrestrial carbon and water fluxes and land use *** suggest that future vegetation modeling could integrate with machine learning,and explore vegetation transient response and feedback as well as impacts of process hierarchies and human activities on climate and ecosystem.

关键词： Vegetation models DGVMs Ecosystems Plant functional types Plant functional traits

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

Global Spherically Symmetric Solutions for a Coupled Compressible Navier–Stokes/Allen–Cahn System

引用

Acta Mathematica Sinica,English Series 2024年第8期40卷 2037-2064页

作者： Chang Ming SONG jian Lin ZHANG Yuan Yuan WANG Department of Applied Mathematics School of Mathematics and Information ScienceZhongyuan University of TechnologyZhengzhou 450007P.R.China

In this paper,we consider the global spherically symmetric solutions for the initial boundary value problem of a coupled compressible Navier–Stokes/Allen–Cahn system which describes the motion of two-phase viscous compressible *** prove the existence and uniqueness of global classical solution,weak solution and strong solution under the assumption of spherically symmetry condition for initial dataρ0 without vacuum state.

关键词： Diffuse interface model global solutions Navier-Stokes equations Allen-Cahn equation spherically symmetry

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

Inverse reliability analysis and design for tunnel face stability considering soil spatial variability

引用

Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1552-1564页

作者： Zheming Zhang jian Ji Xiangfeng Guo Siang Huat Goh Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing210098China Department of Civil and Environmental Engineering National University of SingaporeSingapore

The traditional deterministic analysis for tunnel face stability neglects the uncertainties of geotechnical parameters,while the simplified reliability analysis which models the potential uncertainties by means of random variables usually fails to account for soil spatial *** overcome these limitations,this study proposes an efficient framework for conducting reliability analysis and reliability-based design(RBD)of tunnel face stability in spatially variable soil *** three-dimensional(3D)rotational failure mechanism of the tunnel face is extended to account for the soil spatial variability,and a probabilistic framework is established by coupling the extended mechanism with the improved Hasofer-Lind-Rackwits-Fiessler recursive algorithm(iHLRF)as well as its inverse analysis *** proposed framework allows for rapid and precise reliability analysis and RBD of tunnel face *** demonstrate the feasibility and efficacy of the proposed framework,an illustrative case of tunnelling in frictional soils is presented,where the soil's cohesion and friction angle are modelled as two anisotropic cross-correlated lognormal random *** results show that the proposed method can accurately estimate the failure probability(or reliability index)regarding the tunnel face stability and can efficiently determine the required supporting pressure for a target reliability index with soil spatial variability being taken into ***,this study reveals the impact of various factors on the support pressure,including coefficient of variation,cross-correlation between cohesion and friction angle,as well as autocorrelation distance of spatially variable soil *** results also demonstrate the feasibility of using the forward and/or inverse first-order reliability method(FORM)in high-dimensional stochastic *** is hoped that this study may provide a practical and reliable framework for determining the stability of tunnels in complex

关键词： Limit analysis Tunnel face stability Spatial variability HLRF algorithm Inverse reliability method

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

Ambarzumyan's Theorem for the Dirac Operator on Equilateral Tree Graphs

引用

Acta Mathematicae Applicatae Sinica 2024年第2期40卷 568-576页

作者： Dong-Jie WU Xin-jian XU Chuan-Fu YANG Department of Mathematics School of Mathematics and StatisticsNanjing University of Science and TechnologyNanjing 210094China

The classical Ambarzumyan’s theorem states that if the Neumann eigenvalues of the Sturm-Liouville operator-d^(2./dx^(2.+q with an integrable real-valued potential q on[0,π] are {n^(2.:n≥0},then q=0 for almost all x∈[0,π].In this work,the classical Ambarzumyan’s theorem is extended to the Dirac operator on equilateral tree *** prove that if the spectrum of the Dirac operator on graphs coincides with the unperturbed case,then the potential is identically zero.

关键词： dirac operator quantum graph Ambarzumyan’s theorem inverse spectral problem

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

Higher-order properties and extensions for indirect MRAC and APPC of linear systems

引用

Science China(Information Sciences) 2024年第4期67卷 218-238页

作者： Yanjun ZHANG Zhipeng ZHANG jian SUN Lei WANG kangkang ZHANG National Key Lab of Autonomous Intelligent Unmanned Systems Beijing Institute of Technology Beijing Institute of Technology Chongqing Innovation Center College of Control Science and Engineering Zhejiang University Department of Electrical and Electronic Engineering Imperial College London KIOS Research and Innovation Center of Excellence University of Cyprus

Recently, a reference derived some new higher-order output tracking properties for direct model reference adaptive control(MRAC) of linear time-invariant(LTI) systems: limt→∞ e~((i))(t) = 0, i = 1,..., n~*-1, where n~* and e~((i))(t) denote the relative degree of the system and the i-th derivative of the output tracking error, respectively. However, a naturally arising question involves whether indirect adaptive control(including indirect MRAC and indirect adaptive pole placement control) of LTI systems still has higher-order tracking properties. Such properties have not been reported in the literature. Therefore, this paper provides an affirmative answer to this question. Such higher-order tracking properties are new discoveries since they hold without any additional design conditions and, in particular, without the persistent excitation condition. Given the higher-order properties, a new adaptive control system is developed with stronger tracking features.(1) It can track a reference signal with any order derivatives being unknown.(2. It has higher-order exponential or practical output tracking properties.(3) Finally, it is different from the usual MRAC system, whose reference signal’s derivatives up to the n~* order are assumed to be known. Finally, two simulation examples are provided to verify the theoretical results obtained in this paper.

关键词： higher-order tracking indirect adaptive control model reference adaptive control adaptive pole placement control

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Ramsey Numbers of Trees Versus Multiple Copies of Books

引用

Acta Mathematicae Applicatae Sinica 2024年第3期40卷 600-612页

作者： Xiao-bing GUO Si-nan HU Yue-jian PENG School of Mathematical Sciences Luoyang Normal UniversityLuoyang 471934China School of Mathematics Hunan UniversityChangsha 410082China

Given two graphs G and H,the Ramsey number R(G,H) is the minimum integer N such that any two-coloring of the edges of K_(N) in red or blue yields a red G or a blue *** v(G) be the number of vertices of G and χ(G) be the chromatic number of *** s(G) denote the chromatic surplus of G,the number of vertices in a minimum color class among all proper χ(G)-colorings of *** showed that R(G,H)≥(v(G)-1)(χ(H)-1)+s(H) if G is connected and v(G)≥s(H).A connected graph G is H-good if R(G,H)=(v(G)-1)(χ(H)-1)+s(H).Let tH denote the disjoint union of t copies of graph H,and let G∨H denote the join of G and *** a complete graph on n vertices by K_(n),and a tree on n vertices by T_(n).Denote a book with n pages by B_(n),i.e.,the join K_(2. ∨■.Erd?s,Faudree,Rousseau and Schelp proved that T_(n) is B_(m)-good if n≥*** this paper,we obtain the exact Ramsey number of T_(n) versus 2._(2..Our result implies that T_(n) is 2._(2.-good if n≥5.

关键词： ramsey number ramsey goodness tree book

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：