检索结果-南通市图书馆

SHRIMP zircon U-Pb geochronology of early Mesozoic felsic igneous rocks from the southern Lancangjiang and its tectonic implications

在线全文

学校读者我要写书评

暂无评论

Science china Earth sciences 2006年第10期49卷 1032-1042页

作者： PENG Touping1,2, WANG Yuejun1, FAN Weiming1, LIU Dunyi3. SHI Yuruo3.& MIAO Laicheng4 1. Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou institute of Geochemistry, Chinese academy of sciences, Guangzhou 510640, {3. 2. Graduate University of Chinese academy of sciences, beijing 10003., {3. 3. SHRIMP isotope Laboratory, Chinese academy of Geological sciences, beijing 10003., {3. 4. institute of Geology and Geophysics, Chinese academy of sciences, beijing 100029, {3. Key Laboratory of Isotope Geochronology and Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China Graduate University of Chinese academy of sciences Beijing China SHRIMP isotope Laboratory Chinese Academy of Geological Sciences Beijing China institute of Geology and Geophysics Chinese Academy of Sciences Beijing China

The SHRIMP zircon U-Pb geochronology of three typical samples, including two monzo nitic granites from the Lincang batholith and a rhyolite from the Manghuai Formation are presented in the southern Lancangjiang, western Yunnan Province. The analyses of zircons for the biotite monzonitic granites from the northern (02DX-13.) and southern (20JH-10) Lincang batholith show the single and tight clusters on the concordia, and yield the weighted mean 206Pb/23.U ages of 229.4 ± 3.0 Ma and 23..4 ± 3.6 Ma, respectively, representing the crystallized ages of these granites. The zircons for the rhyolitic sample (02DX-95) from the Manghuai Formation give a weighted mean 206Pb/23.U age of 23..0 ± 5.0 Ma. These data suggest that the igneous rocks from the Lincang granitic batholith and Manghuai Formation have a similar crystallized age. In combination with other data, it is inferred that both were generated at a narrow age span (~23. Ma) and were originated from the postcollisional tectonic regime. An early Proterozoic 206Pb/23.U apparent age of 1977±44 Ma is additionally obtained from one zircon from the biotite monzonitic granite (southern Lincang batholith), indicative of devel- opment of the early Proterozoic Yangtze basement in the region. These precisely geochronological data provide important constraints on better understanding the Paleozoic tectonic evolution of the Tethys, western Yunnan Province.

关键词： SHRIMP zircon U-Pb dating, Middle Triassic, Lincang granitic batholith, Manghuai Formation rhyolite, southern Lancangjiang.

Relationships between tree-ring width index and NDVI of grassland in Delingha

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2006年第9期51卷 1106-1114页

作者： HE Jicheng1,3.& SHAO Xuemei1,21. institute of Geographical sciences and Natural Resources Research, Chinese academy of sciences, beijing 100101, china 2. institute of Tibetan Plateau Research, Chinese academy of sciences, beijing 100085, china 3. Graduate School of Chinese academy of sciences, beijing 10003., china institute of Geographical sciences and Natural Resources Research Chinese Academy of Sciences Beijing China Graduate School of Chinese academy of sciences Beijing China institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing China

Using five well-replicated Qilian juniper (Sabina przewalskii Kom.) tree-ring width index se- ries, monthly normalized difference vegetation index (NDVI) of grassland, and climatic data from 1982 to 2001, the relationships between tree-ring width index, NDVI of grassland, and climatic data were analyzed firstly. Then, the relationship between tree-ring width index and NDVI of grassland was explored. The re- sults showed that: (1) Temperature and precipitation in June influenced tree-ring width index and NDVI of grassland deeply in Delingha. (2) There were sig- nificant relationships between five tree-ring width index series (DLH1-DLH5) and monthly NDVI of grassland from June to September, with the most significant relationship being between tree-ring width index series and NDVI of grassland in August. (3. The PC1 (the first principal component derived from DLH1-DLH5 series) exhibited good agreement with monthly NDVI of grassland in the grass growth sea- son (from June to September) and the averaged NDVI in the growth season, which was attributed to their common responses to water-supply limit in Delingha. This study may allow an increase in studying the past dynamics of grassland in Delingha in that the variation of grassland NDVI during the last millennium has been reconstructed from PC1.

关键词：圆柏祁连山 NDVI 草原年轮宽度指数

A new DNA algorithm to solve graph coloring problem

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第6期17卷 733-738页

作者： Jiang Xingpeng1, Li Yin2, Meng Ya3.and Meng Dazhi2(1. National Laboratory of Pattern Recognition,institute of Automation, Chinese academy of sciences, {3. 100080, china 2. College of Applied sciences, {3. University of Technology, {3. 100022, china 3. School of Science, {3. institute of Technology, {3. 100081, china) National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Beijing 100080 China College of Applied sciences Beijing University of Technology Beijing 100022 China School of Science Beijing Institute of Technology Beijing 100081 China

Using a small quantity of DNA molecules and little experimental time to solve complex problems successfully is a goal of DNA computing. Some NP-hard problems have been solved by DNA computing with lower time complexity than conventional computing. However, this advantage often brings higher space complexity and needs a large number of DNA encoding molecules. One example is graph coloring problem. Current DNA algorithms need exponentially increasing DNA encoding strands with the growing of problem size. Here we propose a new DNA algorithm of graph coloring problem based on the proof of four-color theorem. This algorithm has good properties of needing a relatively small number of operations in polynomial time and needing a small number of DNA encoding molecules (we need only 6R DNA encoding molecules if the number of regions in a graph is R).

关键词： DNA computing NP-hard problem graph coloring problem.

The lepton flavor violating signal of the extra gauge boson Z′in photon-photon collision at the ILC

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2010年第11期53卷 1992-1997页

作者： LIU GuoLi 1,2 1 Physics Department,Zhengzhou University,Zhengzhou 450001,china 2 Kavli institute for Theoretical Physics china,Chinese {3. of sciences,beijing 100190,china 1. Physics Department Zhengzhou University Zhengzhou 450001 China2. Kavli Institute for Theoretical Physics China Chinese Academy of Sciences Beijing 100190 China

The hitherto unconstrained lepton flavor mixings,induced by the new gauge boson Z ,which are the prediction of many new physics models,such as topcolor-assisted technicolor (TC2) models and flavor-universal TC2 models,may lead to the lepton flavor violating productions of τμˉ,τeˉ and μeˉ in photon-photon collision at the proposed International Linear Collider (ILC).Through a comparative analysis of these processes,we find that the better channel to probe the new physics models is the production of τμˉ or τeˉ which occurs at a much higher rate than μeˉ production due to the large mixing angle and the large flavor changing coupling,and may reach the detectable level of the ILC for a large part of the parameter *** the rates predicted by the Standard Model are far below the detectable level,these processes may serve as a sensitive probe for such new physics models.

关键词： new gauge boson Z lepton flavor violating processes photon-photon

Modeling and verifying Web services driven by requirements:An ontology-based approach

在线全文

学校读者我要写书评

暂无评论

Science in china(Series F) 2006年第6期49卷 792-820页

作者： HOU Lishan1,3.JIN ZHi1,2 & WU Budan1,4 1. academy of Mathematics and Systems Science, Chinese academy of sciences, {3. 100080, china 2. institute of Computing Technology, Chinese academy of sciences, {3. 100080, china 3. institute of Software, Chinese academy of sciences, {3. 100080, china 4. Graduate University of Chinese academy of sciences, {3. 100049, china 1. academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China 3. institute of Software Chinese Academy of Sciences Beijing 100080 China 2. institute of Computing Technology Chinese Academy of Sciences Bejing 100080 China 4. Graduate University of Chinese academy of sciences Beijing 100049 China

Automatic discovery and composition of Web services is an important research area in Web service technology, in which the specification of Web services is a key issue. This paper presents a Web service capability description framework based on the environment ontology. This framework depicts Web services capability in two aspects： the operable environment and the environment changes resulting from behaviors of the Web service. On the basis of the framework, a requirement-driven Web service composition model has been constructed. This paper brings forward the formalization of Web service interactions with π calculus. And an automatic mechanism converting conceptual capability description to the formal process expression has been built. This kind of formal specification assists in verifying whether the composite Web service model matches the requirement.

关键词： Web service environment ontology automatic composition π calculus formal verification.

Experimental results and analysis of sparse microwave imaging from spaceborne radar raw data

在线全文

学校读者我要写书评

暂无评论

Science china(Information sciences) 2012年第8期55卷 1801-1815页

作者： JIANG ChengLong1,2,3.ZHANG BingChen1,2,ZHANG Zhe1,2,3.HONG Wen1,2&WU YiRong1,2 1S cience and Technology on Microwave Imaging Laboratory,beijing 100190,china 2I nstitute of electronics,Chinese {3. of sciences,beijing 100190,china 3. raduate University of Chinese {3. of sciences,beijing 100190,china 1. Science and Technology on Microwave Imaging Laboratory Beijing 100190 China2. Institute of Electronics Chinese Academy of Sciences Beijing 100190 China3. Graduate University of Chinese Academy of Sciences Beijing 100190 China

Sparse microwave imaging is a novel radar framework aiming to bring revolutions to the microwave imaging according to the theory of sparse signal *** compressive sensing(CS)is introduced to synthetic aperture radar(SAR)imaging in recent years,the current SAR sparse imaging methods have shown their advantages over the traditional matched filtering ***,the requirement for these methods to process the compressed range data results in the increase of the hardware *** the SAR sparse imaging method that directly uses the raw data is *** paper describes the method of SAR sparse imaging with raw data directly,presents the analysis of the signal-to-noise ratio(SNR)in the echo signal by combining the traditional radar equation with the compressive sensing theory,and provides the tests on 2-D simulated SAR *** simulation results demonstrate the validity of the SNR analysis,and the good performance of the proposed method while a large percentage of the raw data is *** experiment with RadarSat-1 raw data is also carried out to show the feasibility of processing the real SAR data via the method proposed in this *** method is helpful for designing new SAR systems.

关键词： sparse microwave imaging synthetic aperture radar(SAR)imaging compressive sensing signalto-noise ratio raw data

Interface delamination of the thermal barrier coating subjected to local heating

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Technological sciences) 2010年第12期53卷 3168-3174页

作者： WU ChenWu, HUANG ChenGuang & CHEN GuangNan institute of Mechanics, Chinese academy of sciences, {3., china 1. institute of Mechanics Chinese Academy of Sciences Beijing 100190 China

To investigate the possible failure modes of the thermal barrier coating (TBC) used to protect the scramjet combustion chamber, the local heating via laser beam irradiation was utilized to simulate the service condition of high thermal flux and high temperature gradient. Firstly, the experimental method and process were described and the typical fracture morphology of the TBC under test were provided. Then, the theoretical and finite element modeling were carried out to study the temperature, deformation and stresses of the specimen when the top ceramic coat was subjected to local heating, and to demonstrate the mechanism on the failure of the TBC. It is revealed that the interface delamination shall appear and ultimately lead to the failure of the TBC under such thermal loading of local quick heating. According to the outcome of this study, the driving force of the interface delamination is influenced greatly by the key structural parameters and performance matching. Moreover, by utilizing the rules of the effects of these parameters on the fracture driving force, there is some possibility for the designer to optimize the performances of the TBC.

关键词： TBC local heating interface delamination FE modeling

Sparse microwave imaging:Principles and applications

在线全文

学校读者我要写书评

暂无评论

Science china(Information sciences) 2012年第8期55卷 1722-1754页

作者： ZHANG BingChen1,2,HONG Wen1,2 & WU YiRong1,2 1Science and Technology on Microwave Imaging Laboratory,beijing 100190,china 2institute of {3.,Chinese academy of sciences,beijing 100190,china 1. Science and Technology on Microwave Imaging Laboratory Beijing 100190 China2. Institute of Electronics Chinese Academy of Sciences Beijing 100190 China

This paper provides principles and applications of the sparse microwave imaging theory and *** aperture radar(SAR) is an important method of modern remote *** decades microwave imaging technology has achieved remarkable progress in the system performance of microwave imaging technology,and at the same time encountered increasing complexity in system *** sparse microwave imaging introduces the sparse signal processing theory to radar imaging to obtain new theory,new system and new methodology of microwave *** on classical SAR imaging model and fundamental theories of sparse signal processing,we can derive the model of sparse microwave imaging,which is a sparse measurement and recovery problem and can be solved with various *** exist several fundamental points that must be considered in the efforts of applying sparse signal processing to radar imaging,including sparse representation,measurement matrix construction,unambiguity reconstruction and performance *** on these considerations,the sparse signal processing could be successfully applied to radar imaging,and achieve benefits in several aspects,including improvement of image quality,reduction of data amount for sparse scene and enhancement of system *** sparse signal processing has also been applied in several specific radar imaging applications.

关键词： sparse microwave imaging sparse signal processing compressive sensing synthetic aperture radar radar imaging

A SAR sidelobe suppression algorithm based on modified spatially variant apodization

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Technological sciences) 2010年第9期53卷 2542-2551页

作者： NI Chong1,2,WANG YanFei1,XU XiangHui1,ZHOU ChangYi1 & CUI PengFei1,2 1 institute of electronics,Chinese academy of {3.,beijing 100190,china 2 Graduate University of Chinese academy of {3.,beijing 10003.,china 1. institute of electronics Chinese Academy of Sciences Beijing 100190 China2. Graduate University of Chinese Academy of Sciences Beijing 100039 China

The existing spatially variant apodizations (SVAs) either cannot depress the sidelobes effectively or reduce the energy of the *** improve this,a modified SVA (MSVA) is put forward in this paper,which expands the traditional filter from 3.taps to 5-taps and sets relevant parameters according to different sampling rates to get the excellent result that satisfies constrained optimization theory.A method for synthetic aperture radar (SAR) sidelobe control based on MSVA is presented,which applies MSVA to range compression and azimuth compression to control *** method which is available for any Nyquist sampling rate can both depress the sidelobes effectively and keep the energy of the mainlobe and the resolution of the *** method can reduce sidelobe levels more effectively than classical amplitude weighting while maintaining the image resolution,as demonstrated by the result of the experiment.

关键词： synthetic aperture radar sidelobe suppression resolution SVA