检索结果-南通市图书馆

Cenozoic volcanic rocks in the Belog Co area, Qiangtang, northern Tibet, china: Petrochemical evidence for partial melting of the mantle-crust transition zone

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Geochimica 2007年第3期26卷 305-311页

作者： LAI Shaocong, QIN Jiangfeng, LI Yongfeng, and LIU xin State Key Laboratory of Continental Dynamics, department of Geology, northwest university, xi’an 710069, china State Key Laboratory of Continental Dynamics Department of Geology Northwest University Xi’an China

Neogene volcanic rocks in the Belog Co area, Qiangtang, northern Tibet, are represented by a typical intermediate-basic and intermediate alkaline rock association, with latite-trachyte as the main rock type. The results of chemical analysis are: SiO2=52%–62%, Al2O3>15%, Na2O/K2O>1 and MgO<3.30%. In addition, the volcanic rocks are LREE-enriched with LREE/HREE=10–13, (La/Yb)N=15–19, and show a weak negative Eu anomaly with δEu=0.71–0.89. The close relationship between Mg# and SiO2 and the co-variation of the magmatophile elements and ultra-magmatophile elements such as La/Sm-La and Cr-Tb indicate that this association of volcanic rocks is the product of comagmatic fractional crystallization. The rock association type and lower Sm/Yb values (Sm/Yb=3.23–3.97) imply that this association of volcanic rocks should have originated from partial melting of spinel lherzolite in the lithospheric mantle. On the other hand, the weak negative Eu anomaly and relative depletion in Nb, Ta and Ti reflect the features of terrigenous magma. So the Neogene Belog Co alkaline volcanic rocks should be the result of partial melting of the special crust-mantle transition zone on the Qinghai-Tibet Plateau.

关键词： major and trace elements Cenozoic volcanic rock mantle-crust transition zone Qinghai-Tibet Plateau

CENOZOIC SEDIMENTARY SEQUENCE IN THE KUMUKULI BASIN, xiNJIANG AND NEW EVIDENCE ON LATE QUATERNARY UPLIFT OF THE QINGHAI—TIBETAN PLATEAU

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

地学前缘 2000年第S1期7卷 213-215页

作者： Zhang Yunxiang, Che Zicheng, Liu Liang (department of Geology, northwest university, xi’an 710069,china)

The elevation of Qinghai\|Tibetan plateau is a epoch\|making event in the global evolutionary history, which not only constructed the modern magnificent geomorphic feature, but also influenced far\|reachingly the global climate. The evolutionary models of its uplifting time and scope has been primarily set up, and is waiting to be competed with new discovery and supplement. A comprehensive field geologic excursion on the Cenozoic strata of the Kumukuli basin, xinjiang, northwest Qinghai\|Tibetan plateau by authors has collected a lot of first\|hand data, and the discovery and dating of the late Pleistocene mammal fossils made an important supplement to the scarcity of late Quaternary fossil recorders in many basins, as well as contributed a great deal to the quantitative study of the researches alike, in the main time, provided new evidences to the uplift of Qinghai\|Tibetan plateau since late *** in the northwest part of the Qinghai\|Tibetan plateau, and between the Kunlun and Altum Mountain ranges, Kumukuli basin is a intracontinental plateau basin, with a mean elevation about 4000m. Cenozoic strata have a time span from Oligocene to *** stratigraphic and lithologic association displays that the development of Kumukuli basin started at the Oligocene, at the primary uplift stage of the Qinghai\|Tibetan plateau. The Oligocene and Miocene, with a giant thickness and multiple layers of thick conglomerate, is of the products of stronger erosional stage, and a reflection of higher differential in inner geomorphology of the plateau. The aggradation led to the smoothness of the geomorphic feature and fineness of sedimentary particle since Pliocene. Since then, Large scale conglomerate outcroped in the peripheral of the plateau, and differential of geomorphology in the plateau and its peripheral areas became distinct. Kumukuli basin is one of the synchronously developed basin with the plateau, having the most completed Cenozoic sequence with a thic

关键词： Qinghai\|Tibetan plateau Cenozoic sedimentary sequ ence mammal fossils

A Systematic Analysis of Early Life Exposure to the Chinese Famine(1959-1961)and the Health of Older Adults-china,2008-2023

在线全文

学校读者我要写书评

暂无评论

china CDC weekly 2024年第11期6卷 203-207,I0001-I0003页

作者： Chi Shen xi Chen School of Public Policy and Administration Xi’an Jiaotong UniversityXi’an CityShaanxi ProvinceChina department of Health Policy and Management Yale School of Public HealthNew HavenCTU.S department of Economics Yale UniversityNew HavenCTU.S

What is already known about this topic?There is mounting evidence indicating that the aging process initiates during early life stages,with in utero the individual’s environment playing a significant ***,it is crucial to comprehend the enduring effects of early life circumstances on health in old *** is added by this report?In this study,we conducted a meta-analysis to examine the effects of the Chinese Famine(1959–1961)on the health of older *** also explored potential mechanisms underlying these *** are the implications for public health practice?The complex interplay between early life circumstances,multiple health-related sectors,and healthy aging necessitates a comprehensive life-course approach and strategic interventions to enhance public health in an aging society.

关键词： life aging mount

A GOLDSTEIN'S TYPE PROJECTION METHOD FOR A CLASSOF VARIANT VARIATIONAL INEQUALITIES

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

Journal of Computational mathematics 1999年第4期17卷 425-434页

作者： Bing-sheng He(department of mathematics, Nanjing university, Nanjing 210008, china) department of mathematics Nanjing University Nanjing 210008 China

Some optimization problems in mathematical programming can be translated to a variant variational inequality of the following form: Find a vectoru*, such that This paper presents a simple iterative method for solving this class of variational inequalities. The method can be viewed as an extension of theGoldstein's projection method. Some results of preliminary numerical experiments are given to indicate its applications.

关键词： Variational inequality Goldstein projection method.

ON MATRIX UNITARILY INVARIANT NORM CONDITION NUMBER

在线全文

学校读者我要写书评

暂无评论

Journal of Computational mathematics 1998年第2期16卷 121-128页

作者： Dao-sheng Zheng (department of mathematics, East china Normal university, Shanghai 200062, china) 华东师范大学数学系上海

In this paper, the unitarily invariant norm \\.\\ on C-mxn is used. We first discuss the problem under what case, a rectangular matrix A has minimum condition number K(A) = \\A\\ \\A(+)\\, where A(+) designates the Moore-Penrose inverse of A; and under what condition, a square matrix A has minimum condition number for its eigenproblem? Then we consider the second problem, i.e., optimum of K(A) = \\A\\ \\A(-1)\\(2) in error estimation.

关键词： matrix unitarily invariant norm condition number

THE CONVERGENCE ON A FAMILY OF ITERATIONS WITH CUBIC ORDER

在线全文

学校读者我要写书评

暂无评论

Journal of Computational mathematics 2001年第5期19卷 467-474页

作者： Dan-fu Han (department of mathematics, Zhejiang university, Hangzhou 310028, china) 浙江大学浙江杭州 310028

Establishes a convergent theorem for a family of iterations with cubic order by using general convergence hypotheses. Disadvantage of using the cubic majorizing function; Convergence of the majorizing sequence; Overvi... 详细信息

关键词： convergence majorizing method gamma-condition error estimate

CONVERGENCE OF THE POINT VORTEX METHODS FOR EULER EQUATION ON HALF PLANE

在线全文

学校读者我要写书评

暂无评论

Journal of Computational mathematics 1996年第3期14卷 213-222页

作者： P.W. Zhang(department of mathematics, Beijing university, Beijing, china) 北京大学数学系北京

In this paper, we study the point vortex method for 2-D Euler equation of incompressible how on the half plane, and the explicit Euler's scheme is considered with the reflection method handling the boundary condition.... 详细信息

关键词： Math CONVERGENCE OF THE POINT VORTEX METHODS FOR EULER EQUATION ON HALF PLANE Zhang

THE GROWTH THEOREM FOR STARLIKE MAPPINGS ON BOUNDED STARLIKE CIRCULAR DOMAINS

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of mathematics,Series B 1998年第4期19卷 401-408页

作者： LIU TAISHUN (department of mathematics, university of Science and Technology of china, Hefei 230026, china)REN GUANGBIN (department of mathematics, university of Science and Technology of china, Hefei 230026, china) department of mathematics University of Science and Technology of China Hefei 230026 China

The authors obtain the growth and covering theorem for the class of normalized biholomorphic starlike mappings on bounded starlike circular *** type of domain discussed is rather general, since the domain must be starlike if there exists a normalized biholomorphic starlike mapping on it. In the unit disc, it is just the famous growth and covering theorem for univalent *** theorem successfully realizes the initial idea of H. Cartan about how to extend geometric function theory from one variable to several complex variables.

关键词： Starlike mappings Growth theorem Starlike circular domains

SOLVING TRUST REGION PROBLEM IN LARGE SCALEOPTIMIZATION

在线全文

学校读者我要写书评

暂无评论

Journal of Computational mathematics 2000年第1期18卷 1-12页

作者： Bing-sheng He(department of mathematics, Nanjing university, Naming 210093, china) 南京大学江苏南京 210093

Presents a study which introduced a method for solving trust region problem in scale minimization. Review of the conjugate gradient method (CG) and the projection and contraction (PC) method; Convergence behavior of t... 详细信息

关键词： trust region problem conjugate gradient method projection and contraction method