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1.55 μm Wavelength Operation of E_r^(3+) -Doped Optical Fiber Bistability

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wuhan university Journal of Natural {{2. 1999年第4期4卷 435-438页

作者： SONG Qian 1, ZHANG Yuan cheng 2... College of Electronics information,{2., {2..430072. China 2..department of Physics,{2., {2..430072. China wuhan university College of Electronics Information Wuhan China (GRID:grid.49470.3e) (ISNI:***) wuhan university Department of Physics Wuhan China (GRID:grid.49470.3e) (ISNI:***)

An all optical all fiber optical bistability operation has been realized in an all fiber cavity consisted with Er doped fiber and optical fiber loop mirrors. The experimental bistability threshold is consistent w... 详细信息

关键词： optical nonlinearity optical bistability Er doped fiber all fiber device

Hierarchical Classification of Chinese Documents Based on N grams

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wuhan university Journal of Natural {{2. 2001年第Z1期6卷 416-422页

作者： Zhou Shui geng 1, Guan Ji hong 2..He Yan xiang 2... State Key Laboratory of Software Engineering,{2., wuhan {2..China 2..School of Computer science,{2., wuhan {2..China State Key Laboratory of Software Engineering Wuhan University Wuhan China School of Computer science Wuhan University Wuhan China

We explore the techniques of utilizing N gram information to categorize Chinese text documents hierarchically so that the classifier can shake off the burden of large dictionaries and complex segmentation processing, and subsequently be domain and time independent. A hierarchical Chinese text classifier is implemented. Experimental results show that hierarchically classifying Chinese text documents based N grams can achieve satisfactory performance and outperforms the other traditional Chinese text classifiers.

关键词： Chinese text classification N grams feature selection hierarchical classification

An efficient method for detecting concurrency errors in object-oriented programs

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science China(information sciences) 2012年第12期55卷 2774-2784页

作者： HE YanXiang 1,2..U Wei 2.. CHEN Yong 2.. School of Computers,wuhan university,wuhan 430072.China 2..tate Key Laboratory of Software Engineering,wuhan university,wuhan 430072.China School of Computers Wuhan University Wuhan China State Key Laboratory of Software Engineering Wuhan University Wuhan China

Multicore and multi-threaded processors have become the norm for modern ***,concurrent programs have become more and more prevalent despite being difficult to write and *** errors are highly likely to appear in concurrent code,conventional error detection methods such as model checking,theorem proving,and code analysis do not scale smoothly to concurrent *** is an indispensable technique for detecting concurrency errors,but it involves a great deal of manual work and is *** paper presents an automatic method for detecting concurrency errors in classes in object-oriented *** method uses a heuristic algorithm to automatically generate test cases that can effectively trigger ***,each test case is executed automatically and a fast method is adopted to identify the actual concurrency error from anomalous run *** have implemented a prototype of the method and applied it to some typical Java *** shows that our method is more effective and faster than previous work.

关键词： concurrency error dynamic test data race atomicity violations test case generation

Preparation and Characterization of Chitosan/Carboxymethylated Konjac Glucomannan Blend Films

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wuhan university Journal of Natural {{2. 2002年第1期7卷 107-112页

作者： Zheng Hua 1 , Du Yu-min 2... department of Chemical Engineering,{2. of Technology, {2..430070, Hubei, China 2..College of Chemistry and Molecular sciences,{2., {2..430072. Hubei, China department of Chemical Engineering Wuhan University of Technology Wuhan Hubei China College of Chemistry and Molecular sciences Wuhan University Wuhan Hubei China

In order to improve the mechanical and water swelling properties of the chitosan (CS) film, a series of transparent films were prepared by blending 2..weight) chitosan acetic acid solution with 1.5%(weight) carboxymethylated konjac glucomannan (CMKGM) aqueous solution according to predetermined ratio and drying at 30°C. The morphological structure, miscibility, thermal stability, mechanical properies, and swelling capacity of the blend films were studied by infrared (IR), X-ray diffraction (XRD), differential thermal analysis (DTA), scanning electron micrograph (SEM), and measurements of the mechanical properties and swelling properties. The results demonstrated that there was strong interaction and good miscibility between CS and CMKGM resulted from intermolecular hydrogen bonding and electrostatic force. The mechanical properties in dry state and wet state, thermostability, and water swelling properties of the blend films were obviously improved. The best values of the tensile strength in the dry and wet state achieved 89 MPa and 49 MPa, respectively, when the CMKGM content was 30%(weight). The CS/ CMKGM blend films provided promising biomedical applications.

关键词： Key words chitosan carboxymethylated konjac glucomannan blend films structure characterization

A hybrid matching method for geospatial services in a composition-oriented environment

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science China(Technological sciences) 2010年第S1期53卷 213-220页

作者： LUO An 1,2..ANG YanDong 1,2.. CHEN ShengHua 2.. State Key Laboratory of Software Engineering,wuhan university,wuhan 430072.China 2..tate Key Laboratory of information Engineering in Surveying,Mapping and Remote Sensing,wuhan university,wuhan 430079,China State Key Laboratory of Software Engineering Wuhan University Wuhan China State Key Laboratory of information Engineering in Surveying Mapping and Remote Sensing Wuhan University Wuhan China

With the development of Internet and GIS,large volumes of spatial data,powerful computing resources and many spatial data processing functions are published in the form of Web *** suitable geospatial services in the composition-oriented environment is a crucial *** semantic Web provides a kind of technology to find and compose various service resources automatically through the *** paper proposes a hybrid method for the semantic matching of geospatial *** method includes two *** 1 puts forward a multi-level semantic matching approach,which matches single geospatial service at four levels:classification,input/output,precondition/effect and the quality of service(QoS).This multi-level matching approach makes single service matching quicker and more *** 2..uts forward a matching algorithm for a geospatial service chain based on the *** algorithm adopts a trace algorithm,taking account of the effect of the *** restricts the input/output parameters of the current service by the input/output parameters of service chain,pre-service and *** matches the atomic service dynamically in a composition-oriented environment,and accurately converts the abstract model of geospatial services into an executable geospatial service chain.A case study of the flood analysis for the Poyang Lake illustrates the effectiveness of our context-based matching method for geospatial services.

关键词： geospatial services semantic context composition service match

Capability of evolutionary cryptosystems against differential cryptanalysis

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science China(information sciences) 2011年第10期54卷 1991-2000页

作者： ZHANG HuanGuo 1,2..LI ChunLei 1,2.. TANG Ming 1,2.. School of Computer,wuhan university,wuhan 430072.China 2..ey Laboratory of Aerospace information Security and Trusted Computing of Ministry of Education,wuhan university,wuhan 430072.China School of Computer Wuhan University Wuhan China Key Laboratory of Aerospace information Security and Trusted Computing of Ministry of Education Wuhan University Wuhan China

The evolutionary cryptosystem is a new *** paper studies its security level resisting against differential *** is shown that the evolutionary cryptosystem possesses higher resistance than its initial fixed cryptosystem against differential *** the basis of the relationship among the data complexity,the bit advantage and the success rate of differential cryptanalysis,it is proven that more data is needed for attacking the evolutionary cryptosystem when the bit advantage and success rate are ***,it is shown that the time complexity for attacking the evolutionary cryptosystem is higher than that of differential attacking its initial fixed cryptosystem with the same amount of plaintext-ciphertext *** research indicates that the evolutionary cryptosystem is more robust than its initial fixed cryptosystem against differential cryptanalysis.

关键词： information security cryptology evolutionary cryptosystem cryptanalysis differential cryptanalysis

Fabrication of Dense Ultrafine TiAl Alloys by Spark Plasma Synthesis from Mechanically Activiated Powders

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Journal of wuhan university of Technology(Materials science) 2007年第3期22卷 408-411页

作者：夏力 department of Materials Engineering Wuhan University

Powder of Ti-46at%Al alloy was synthesized through mechanical activation（MA） and then sintered and concurrently consolidated in a short sintering time of 900 s by using a spark plasma sintering（SPS） process. The XRD and SEM profiles show that the microstructures of TiAl alloys contained γ TiAl and small amount α-2..i3Al phase, whose amount can be controlled by the sintering temperature. The compacts retained the original fine-grained fully densified bodies by avoiding an excessively high sintering temperature. The alloys sintered at higher temperature with this process showed a coarser microstructure. So it is possible to produce dense nanostructured TiAl alloys by mechanically activated spark plasma sintering （MASPS） within a very short period of time.

关键词： titanium aluminides mechanical activation spark plasma sintering (SPS)

LARGE DEVIATIONS FOR STATIONARY Φ-MIXING SEQUENCES IN τ-TOPOLOGY

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Chinese Annals of Mathematics,Series B 1996年第2期17卷 149-158页

作者： Hu YIJUN department of Mathematics, wuhan university, {{2.430072. China. department of Mathematics Wuhan University Wuhan 430072 China

The results of Bryc on large deviations for empirical measures of stationary Φ-mixing sequences are extended. Bryc states his results in the usual weak topology on the space ofprobability measures. In this paper, under somewhat weaker assumptions than those of Bryc,the author extends Bryc's results by taking the finer topology which is generated by the integralsover bounded measurable functions.

关键词： Large deviation Empirical measure Stationary sequence Φ-mixing τ-topology

Ferroelectric properties of Bi_(3.4)Ho_(0.6)Ti_3O_(12..thin films prepared by sol-gel method

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science China(Technological sciences) 2008年第9期51卷 1439-1444页

作者： FU ChengJu1, HUANG ZhiXiong1, LI Jie2.. GUO DongYun3 1 School of Materials science and Technology,{2. of Technology, {2..430070, China 2..chool of Mechanical Engineering, Chongqing university of science and Technology, Chongqing 400050, China 3 department of Physics,{2., {2..430072. China School of Materials science and Technology Wuhan University of Technology Wuhan China School of Mechanical Engineering Chongqing University of Science and Technology Chongqing China department of Physics Wuhan University Wuhan China

We have prepared the Ho-substituted bismuth titanate (Bi3.4Ho0.6Ti3O12..BHT) thin films on Pt/Ti/SiO2..i substrates using sol-gel method. The crystal structure and morphology of the films were characterized using X-ray diffraction and atomic force microscopy. The BHT film shows a single phase of Bi-layered Aurivillius structure and dense microstructure. The 2.. and 2.. of the 600-nm-thick BHT film were 38.4 μC/cm2..nd 376.1 kV/cm, respectively at applied electric field 500 kV/cm. The dielectric constant and dielectric loss are about 310 and 0.015 at a frequency of 1 MHz, respectively. The Pr value decreased to 93% of its pre-fatigue values after 4.46×109 switching cycles at 1 MHz frenquency, and the BHT film shows good in-sulating behavior according to the test of leakage current.

关键词： Bi3.4Ho0.6Ti3O12 thin film sol-gel method ferroelectric property fatigue dielectric constant