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991.
Dai Le & Gao Meiguo 《系统工程与电子技术(英文版)》2006,17(3):527-530
1 .INTRODUCTIONWith the rapid development of radar technology ,The technology of high-resolution radar i mage for-mationis gradually getting mature , and the coun-termeasure to high-resolution radar is growing a re-search hot point in the field of ECM. In order toattain high-resolution, High-resolutionradar usual-ly adopts the wideband pulse signal with 1 GHzbandwidth and over . So the realization of A/D( Analog/Digital) conversionis more difficult in en-gineering practice . For the s… 相似文献
992.
993.
Xiao YangInstitute of Information Science Northern Jiaotong University Beijing P.R. China 《系统工程与电子技术(英文版)》2002,13(2)
Models of 2-D continuous-discrete systems are introduced, which can be used to describe some complex systems. Different from classical 2-D continuous systems or 2-D discrete systems, the asymptotic stability of the continuous-discrete systems is determined by Hurwitz-Schur stability (hybrid one) of 2-D characteristic polynomials of the systems. An algebraic algorithm with simpler test procedure for Hurwitz-Schur stability test of 2-D polynomials is developed. An example to illustrate the applications of the test approach is provided. 相似文献
994.
YIN Jiarun 《自然科学进展(英文版)》2003,(4)
New fossil collections in the Lanongla area, Tibetan Himalaya enables the establishment of the Upper Jurassic ammonoidsuccession. Middle Oxfordian ammonite-fauna is characterized by endemic epimayaittds with a marine deepening event, suggesling a high stand of sea Ievel in the Tibetan Himalaya. Distribution of mayaitids around the Eastern Gondwana can be regarded as the first signal of the Indo-AustraI Subrealm that was progressively established during the Late Jurassic and Early Cretaceous times. 相似文献
995.
北京分子科学国家实验室 《中国基础科学》2007,9(4):26-32
2000年,科技部针对当前科技发展日益呈现学科交叉和综合的趋势,适应科技发展需要,提出了建设较大规模、学科交叉的国家实验室的思路,并开展了试点工作,在中科院沈阳金属所原有2个国家重点实验室和1个中科院重点实验室基础上,启动筹建了沈阳材料科学国家(联合)实验室,希望通过整 相似文献
996.
ZHU Detong 《系统科学与复杂性》2000,(4)
1. IntroductionGiven some function f(x): Wu - FI over a nonempty closed set n C W", one is interestedin solving the fOllowing optimization problem with constraints amin f(x)s.t. x E n (1.1)where f(x): Q C Wu - FI is twice continuously differentiable. This problem has receivedconsiderable attention extensively. The linear constrained case where n is a polyhedron is ofspecial inferest. Recently, there are quite a few articles proposing projected gradient methodsto solve the problem (see, fo… 相似文献
997.
SUN Jiong 《系统科学与复杂性》2000,(2)
1. IntroductionLet D be an unbounded open set in R"(n 2 2) with finite Lebesgue measure. We considerthe following eigenvalue problem on a.where A = Z:=, 6 denotes the Laplacian on a and r ~ oa, the boundary of g. In thispaper we have a special interest in r which is considerably irregular like a fractal.Let N(A) denote the eigenvalue counting function of (P): the number of eigenvalues notexceeding A. When n is a bounded open set, it is well known that Weyl's classical asymptoticformulae f… 相似文献
998.
XUE Xiangxu ZHOU Weijian(Department of Geology Northwest University Xi’an China)XUE Xiangxu ZHOU Weijian ZHOU Jie J. Head(State Key Laboratory of Loess Quaternary Geology Xi’an China)A.J.T. Jull(NSF-AMS Facility Department of Physics University of Arizona AZ USA)Correspondence should be addressed to Xue Xiangxu 《科学通报(英文版)》2000,45(9):853-857
We have collected a suite ofPaleoloxodon naumanni-Coelodonta antiquitatis fossils from a river terrace profile between Xi’an and Xianyang cities in Guanzhong Area, Shaanxi Province. A detailed examination
of the fossils, together with14C determinations and pollen analyses, have enabled us to reconstruct preliminary features of climate and environment changes
and their evolutionary processes, within the last glacial maximum (LGM): about 20 ka ago, the climate was basically cool and
wet, and was favourable for the existence ofPaleoloxodon naumanni-Coelodonta antiquitatis fauna. This was followed by a cold, dry phase which was no longer suitable for this type of faunal suite, causing the death
of a large number of mammalian assemblages. The available evidence indicates the existence of cold-dry and cool-wet climate
and environment fluctuations during the LGM. The cool-wet stage within the LGM reflects a Heinrich event occurring in the
high latitude areas, proving the existence of a teleconnection between polar-high latitude areas and the Loess Plateau. 相似文献
999.
Ruan Shigui 《咸宁学院学报》1991,(1)
Liapunov functionals of simple form have been used to de-rive new sufficient conditions for uniform asymptotic stability of the zero so-lution of linear neutral differential difference systems. 相似文献
1000.
证明了关于2t+1阶S te iner三连系的存在和构造方面的定理,提出了2t+1阶S te iner三连系构造的具体步骤,介绍了105个不同构的15阶K irkm an三连系构造的全过程,分析了2t+1阶S te iner三连系的计数问题. 相似文献