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Complex Polynomial Vector Fields Having a Finitely Curved Orbit

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Acta Mathematica Sinica,English Series 2007年第12期23卷 2247-2252页

作者： B.scDUA Instituto de Matemática C.P.68530Universidade Federal do Rio de Janeiro

The author proves that a non-singular polynomial vector field without invariant lines and having an entire finitely curved transcendent orbit on C^2 must be equivalent to a trivial vector field by a holomorphic change of coordinates. Other classification results are obtained for polynomial vector fields having a finitely curved orbit on C^2.

关键词： holomorphic foliation minimal immersion Huber-Osserman theorem

DIscRETIZATION OF JUMP STOCHASTIC DIFFERENTIAL EQUATIONS IN TERMS OF MULTIPLE STOCHASTIC INTEGRALS

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Journal of Computational Mathematics 1998年第4期16卷 375-384页

作者： Li, CW Wu, sc Liu, XQ City Univ Hong Kong Dept Math Hong Kong Hong Kong Acad Sinica Inst Appl Math Beijing 100080 Peoples R China Acad Sinica Lab Management Decis & Informat Syst Beijing 100080 Peoples R China

In the Stratonovich-Taylor and Stratonovich-Taylor-Hall discretization schemes for stochastic differential equations (SDEs), there appear two types of multiple stochastic integrals respectively. The present work is to approximate these multiple stochastic integrals by converting them into systems of simple SDEs and solving the systems by lower order numerical schemes. The reliability of this approach is clarified in theory and demonstrated in numerical examples. In consequence, the results are applied to the strong discretization of both continuous and jump SDEs.

关键词： Brownian motion Poisson process stochastic differential equation multiple stochastic integral strong discretization

The isotopic abundance and atomic weight of natural uranium

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Chinese science Bulletin 1997年第10期42卷 814-817页

作者： Liu, YF Fu, sc China Institute of Atomic Energy Beijing China

THERE are three radioactive nuclides of uranium in nature,234U,235U and 238*** isotopicabundance and atomic weight of unanium was reported *** 1983,the International U-nion of Pure and Applied Chemistry（IUPAC）gave a review of the published *** resultsof the review showed the abundance of uraniums,234U:0.000 055（5）;235U:0.007 200（12）;238U:0.992 745（60）,the atomic weight of uranium,A,（U）=238.028 9（1）.

关键词： isotopic abundance of uranium atomic weight of uranium mass spectrometric measurement.

THREE DIMENSIONAL DYNAMIC ELASTICPLASTIC ANALYSIS OF THE INTERACTION OF A SET OF PERCUSSION BITS WITH ROCK MASSES

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Acta Mechanica Solida Sinica 1995年第4期8卷 364-374页

作者： Song, sc Knasmillner, RE INNER MANGOLIA RES INST MET POB 4BAOTOU 014034PEOPLES R CHINA VIENNA TECH UNIV INST MECHA-1040 VIENNAAUSTRIA

A three dimensional dynamic elastic-plastic finite element analysis of the interaction of percussion bits with rock masses is presented. The dynamic contact problem was investigated with the numerical method developed for high velocity impact calculations[1]. The numerical analysis was carried out for three simultaneously loaded percussion bits arranged on a straight line on the rock surface, the loading time was kept constant throughout this work. The numerical calculation for various strengths of the dynamic load tm the percussion bits shows that a critical minimum dynamic load exists for the generation of plastic deformations in the rock. For this critical value of the load the maximum normal stress of the longitudinal wave in the percussion bit exceeds the yield stress of the rock mass.

关键词： rock masses percussion bits numerical analysis

Geographic variation in sexual selection and implications for speciation in the Barn Swallow

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Chinese Birds 2015年第1期5卷 30-42页

作者： Elizabeth sc scordato Rebecca J Safran Department of Ecology and Evolutionary Biology The University of Colorado

Barn Swallows(Hirundo rustica), a group of passerine birds comprised of six closely related subspecies, are well known throughout their nearly worldwide distribution, in part because of their close association with human settlements.A tractable species for both individual-based and population-level studies, Barn Swallows are a prominent model system in evolutionary, ecological, and behavioral research. Here we review work on sexual selection and population divergence in this species complex, focusing on comparative studies among populations and *** summarize variation in the targets of mate choice and in the information conveyed by sexually selected traits, and conclude that the benefits advertised by different traits may vary geographically. Finally, we consider the role of sexual selection as a driver of population divergence in this widespread and phenotypically variable species complex.

关键词： Barn Swallow Geographic variation Natural selection Sexual selection Speciation Tail streamers Ventral color

Proline accumulation in rice seedlings exposed to hydroxyl radical stress in relation to antioxidation

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Chinese science Bulletin 1997年第10期42卷 855-859页

作者： Jiang, MY Guo, sc Zhang, XM Department of Biology Xiangtan Teachers College Xiangtan 411201 China

PROLINE(Pro)is an essential amino acid for proteins and free Pro extensively exists in *** accumulates in plant cells in response to water stress,salinity,low temperature,air pollu-tants,*** has been mainly studied for its role in the osmotic adjustment of plants subject-ed to drought and *** addition to acting as a cytoplasmic osmoticum,Pro

关键词： hydroxyl radical stress proiine accumulation lipid peroxidation antioxidation Oryza sativa L.

Qualification Test for the Reliability of Diver Gas Recovery System

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China Ocean Engineering 1997年第3期12卷 357-361页

作者： Mao, FG Lu, sc Luo, RR Natl Naval Med Res Inst Shanghai 200433 Peoples R China Chinese Navy Headquarters Navigat Guarantee Dept Tianjin 300042 Peoples R China

A qualification test for the reliability of a newly-developed Diver Gas Recovery System (DGRS) was carried out in the Naval Medical Research Institute of the People's Liberation Army, China from March 29 to April 2, 1995. A sequential test plan of high discrimination ratio for the mean time between failures (MTBF) was adopted. The test procedures simulated those of a 300 msw dive. A hyperbaric breathing machine was used for the simulation of diver's respiratory functions. Parameters, such as diving depth, respiratory minute volume (RMV), CO2 production, gas flow rate, partial pressure of carbon dioxide, and ambient temperature and himidity were all displayed and recorded with a microcomputer system. The results indicated that no failure occurred during the 91.5 h operation. According to the acceptance and rejection criteria specified in the statistical test plan, a no-failure score in the 88 h operation is acceptable. Therefore, the DGRS has been demonstrated to meet the requirements of MTBF specified in the contract.

关键词： diver gas recovery system reliability qualification test

A clinical and long-term follow-up study of perioperative sequential triple therapy for gastric cancer

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World Journal of Gastroenterology 2000年第2期6卷 284-286页

作者： Zou sc Qiu HS Zhang CW Tao HQ Zhejiang Prov Peoples Hosp Dept Surg Hangzhou 310014 Zhejiang Peoples R China

INTRODUCTIONAlthough the long-term postoperative survival rateof gastric cancer(GC) patients has been improvedsignificantly since the local dissection of lymph nodewas widely used in China,yet the low curativeresection rate and the high recurrence rate fromperitoneal and hepatic metastases hinder it fromfurther *** alter the currentunsatisfactory status of GC treatment,a

关键词： stomach neoplasms/surgery stomach neoplasms/drug therapy intra-arterial chemotherapy intra-peritoneal chemotherapy curative resection survival rate

New Triterpene Glycoside from Thalictrum smithii

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Chinese Chemical Letters 1999年第6期10卷 485-486页

作者： Yu, sc Wu, QL Wang, LW Xiao, PG Chinese Acad Med sci Inst Med Plant Dev Beijing 100094 Peoples R China Peking Union Med Coll Beijing 100094 Peoples R China

A new triterpene glycoside, 24S-cycloartane-3 beta, 16 beta, 24, 25, 30-pentaol 3-O-(2-O-beta-D-xylosyl)-beta-D-xyloside was isolated from Thalictrum smithii. Its structure was determined by spectroscopic and chemical... 详细信息

关键词： Thalictrum Thalictrum smithii triterpene glycoside 24S-cycloartane-3 beta, 16 beta, 24,25 30-pentaol 3-O-(2-O-beta-D-xylosyl)-beta-D-xyloside