检索结果-南通市图书馆

ON THE MAXIMALITY OF SOME PAIRS OF p-t DEGREES

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1992年第6期37卷 522-523页

作者：郑锡忠 Department of Mathematics Nanjing University Nanjing 210008 PRC

S. A. Cook introduced in [1] the concept of p-t reducibility, and the deduced equivalent class is called the p-t degree which is partially ordered by the relation '≤' which is also deduced from the p-t reducibility. R. E. Ladner and K. Ambos-Spies have given a wide discussion on the structural properties of p-t degrees with '≤'. They proved that there

关键词： discussion deduced branching partially exact ordered letter 内卿 stead

Elements of Finite Order in K_2 of Fields

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1994年第6期39卷 449-451页

作者：秦厚荣 Department of Mathematics Nanjing University Nanjing 210008 PRC

1 Introduction It is important to investigate the elements of finite order in K2 of fields. *** shows that if a global field F contains ξn, a primitive nth root of l, then everyelement of order n in K2F is of the form {ξn,b} for some b∈F. Let Φn.（x） be thenth cycltomic polynomial. For elements of small order in K2F,J. Browkin givesthe following results:

关键词： K2 groups of fields order cyclotomic polynomial.

MODELS OF THE SPATIAL EVOLUTION OF MULTI-PLANT ENTERPRISES

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 1994年第2期4卷 134-147页

作者：费洪平 Department of Geo and Ocean Sciences Nanjing University Nanjing PRC

Since the 1970s, the studies on the geography of enterprise have become increasingly concerned with the spatial evolution of an enterprises in the West developed countries. However, little attention has so far been given to the spatial evolution of an enterprise in China. With China's ongoing economy and political reforms, a number of fundamental changes of enterprise behavior have occurred. These changes have certainly important influences on the evolution of industrial location. Therefore, there is a need for examining the spatial evolution of an enterprise in China. The purpose of the paper is to review the mapjor models of both the growth,and associated spatial evolution of an enterprise, with an illustrative case study of the HeaVy Automobile Enterprise Group of China. The paper is organized by three parts. The first examines the spoilal groWth and location adjustment of multi-plant enterprise. The second reviews mapjor models of the spatial evolution of an enterprise. And the third analyzes the spatial evolution, over a period of time, of a representative sample of the Heavy Automobile Enterprise Group of China, and illustrates the findings with case studies. It is suggested that the models of spatial evolution of an enterprise would provide more evidence about micro-mechanism for evolution of micro- regional economic systems.

关键词： multi-plant enterprises enterprise groups spatial evolution of an enterprise spatial growth location adjustment

EVOLUTION　OF　RAPIDS　OF　CREEK　MOUTH－BAR　AT　GEZHOUBA　RESERVOIR　AND　THE　IMPACTS　ON　NAVIGABLE　CHANNEL　IN　THE　UPPER　REACHES　OF　THE　CHANGJIANG　RIVER

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 1996年第3期6卷 223-230页

作者：林承坤高锡珍 Department of Geo-and Ocean Sciences Nanjing University Nanjing PRC

Almost at every mouth of the tributary creek of the Three Gorges inthe Gezhouba Reservoir, the alluvial fans or alluvial cones formed the rapids, whichare called rapids of creek mouth--bar. They are composed of pebble bed load with d>20 mm. Based upon geological and geomorphological investigations, the authors detect that the pebble bed load at the Gezhouba Re3ervoir comes from two sources,namely, the region mainly with limestone and The region mainly with pyrolith, andtheir converging area is within the Gezhouba Project. percentages of the pebble bedload are calculated. The calculated result stows that, 65% of pebble bed load comesfrom the region mainly with limestone, and 93 % of the rapids of creek mouth--bar isdistributed in the region mainly with limestone. Considering the water level fluctuations, the rapids of creek mouth--bar can be divided into 3 types i. e. flood waterones, medium water ones and low water ones. Due to the rise of water level afterbuilding the Gezhouba Reservoir, the navigable channels in the area of rapids ofcreek mouth--bar within varied back water region are improved, taking up 50% of all12 rapids. But the rapids of creek mouth--bar in the tail region where the water levelrises less than 1 m, the conditions of navigable channels are little improved and evendeterioration, because of the continuous supply of pebble bed load. Therefore, thoserapids must be regulated before the completion of the Three Gorges Project.

关键词： Gezhouba Reservoir pebble bed load rapids of creek mouth--bar navigable channels

EXISTENCE OF BOUNDED SOLUTIONS OF SINGULAR ORDINARY DIFFERENTIAL EQUATIONS

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1992年第21期37卷 1844-1845页

作者：章熙康 Department of Mathematics Nanjing University Nanjing 210008 PRC

We deal with the bounded solution problems of the ordinary differential equations with

关键词： ordinary hasbeen letter norms locally

SURFACE ENHANCED RAMAN SCATTERING STUDIES OF THE CYCLIZATION AND GRAPHITI ZATION OF POLYACRYLONITRILE ON ROUGH SILVER SURFACE

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1992年第16期37卷 1356-1359页

作者：薛奇张峻峰董坚 Department of Chemistry Nanjing University Nanjing 210008 PRC

Polyacrylonitrile (pAN)can undergo structural changes on heating, and after further dehydrogenation and pyrolysis at high temperature above 2000℃, a graphite structure which has high properties will be formed. Recent... 详细信息

关键词： polyacrylonitrile(PAN) surface enhanced Raman scattering(SERS) graphitization.

ORIENTATION DETERMINATION OF HIGH T_c BSCCO SINGLE CRYSTAL BY SIMULATING KOSSEL DIFFRACTION

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1991年第17期36卷 1441-1443页

作者：张建中王文利李百秦沈惠敏徐永兵王业宁 Department of Physics Nanjing University Nanjing 210008 PRC

In order to understand the possible mechanisms responsible for the superconductivity of high T_c oxides, the study of their structures and physical properties is in progress worldwide. The samples investigated are bei... 详细信息

关键词： high T_c superconductive single crystal simulation of pseudo-Kossel diffraction orientation determination.

A Criterion for Weak Homoclinic Attractor in R^3

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1993年第4期38卷 277-280页

作者：孙建华 Department of Mathematics Nanjing University Nanjing 210008 PRC

The existence of a homoclinic orbit is an important qualitative feature of a dynamical system, which often leads to a complicated but well-understood phase portrait nearby. Although considerable progress for the bifurcation of a homoclinic orbit has been achieved under perturbative treatment of those homoclinic systems, the stability of a homoclinic orbit in higher-dimensional system remains almost unknown. In this note, we shall give a

关键词： three-dimensional systems normal forms weak homoclinic attractor.

AGE AND SOURCE MATERIALS OF BAJIATAN AND FANSHAN-SHIMATAN INTRUSIVE ROCKS IN LUJIANG-ZONGYANG DISTRICT, ANHUI PROVINCE

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1991年第19期36卷 1626-1628页

作者：任启江王德滋刘孝善杨荣勇孙冶东邱检生 Department of Geoscience Nanjing University Nanjing 210008 PRC

The Mesozoic volcanic rocks in Lujiang-Zongyang district can be divided into four formations, from early to late, Longmenyuan, Zhuanqiao, Shuangmiao, Fushan. Their isotopic ages are in confusion. For example, the 11 dating data of Zhuanqiao Formation are between 135 Ma and 109 Ma, belonging to K1, whereas other 9 dating data are from 136 Ma to 178 Ma, belonging to J2—J3. Through the studies on Sm-Nd and Rb-Sr isotopic composition of the Bajiatan and Fanshan-Shimatan volcanic-intrusive rocks in the district, some significant data with regard to the ages and source materials of the volcanic-intrusive rocks have been acquired and published in this note.

关键词： volcanic intrusive rocks isotopic composition.