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Properties of Broad Band Continuum of Narrow Line Seyfert 1 Galaxies

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Chinese Journal of Astronomy and Astrophysics 2002年第6期2卷 501-524页

作者： Hong-Yan Zhou and Ting-Gui WangCenter for Astrophysics, university of science and technology of china, Hefei 230026National Astronomical Observatories, Chinese Academic of science, beijing 100012 National Astronomical Observatories Chinese Academic of Science Beijing 100012

We have performed a statistical study of the properties of the broad band continuum of Narrow Line Seyfert 1 galaxies (NLS1s) by collecting ratio, infrared, optical and X-ray continuum data from various databases and compared the results with control samples of Broad Line Seyfert 1 galaxies (BLS1s). We find that the fraction (similar to 6%) of Radio Loud (RL) NLS1s is significantly less than that of BLS1s (similar to 13%), which is caused by the lack of radio-very-loud sources in the former. The rarity of RL NLS1s, especially radio-very-loud ones, is consistent with the scenario of small black hole and high accretion rate for NLS1s. Six new radio loud NLS1s are found and five RL NLS1 candidates are presented. In comparison with the BLS1s, the NLS1s tend to have stronger far infrared emission, cooler infrared colors and redder B - K color, which suggests that NLS1s are hosted by dust-richer nuclei. The NLS1s also show steeper soft X-ray spectrum and large soft X-ray to optical flux ratio, while a significant fraction show flat soft X-ray spectra. At least two factors can account for this, absorption and spectral variability. We also perform a correlation analysis between various broad band data. It is found that most correlations identified for NLS1s are also valid for radio quiet BLS1s: (1) the optical colors are anti-correlated with X-ray spectral index; (2) higher optical, Xray and NIR luminosity objects show bluer optical colors and red H - K color; (3) higher luminosity objects show warmer IRAS color; (4. the radio loudness correlates with B - K and X-ray to optical flux ratio. Radio loud objects behave somewhat differently in a few correlations.

关键词： galaxies : active galaxies : Seyfert radiation : continuum

P2P traffic optimization

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science china(information sciences) 2012年第7期55卷 1475-1492页

作者： ZHANG GuoQiang 1,2 ,TANG MingDong 3 ,CHENG SuQi 2,4.,ZHANG GuoQing 2 ,SONG HaiBin 5 ,CAO JiGuang 6 & YANG Jing 7 1 School of computer science and technology,Nanjing Normal university,Nanjing 21004.,{4. 2 Institute of Computing technology,Chinese Academy of sciences,beijing 100190,{4. 3 School of computer science and Engineering,Hunan university of science and technology,Xiangtan 4.1201,{4. 4.Graduate university of Chinese Academy of sciences,beijing 100190,{4. 5 Nanjing R&D Center,Huawei Technologies,Nanjing 210012,{4. 6 {4. Academy of Telecommunication Research of MIIT,beijing 100191,{4. 7 {4. Mobile Research Institute,beijing 100053,{4. 1. School of computer science and technology Nanjing Normal University Nanjing 210046 China2. Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China3. School of Computer Science and Engineering Hunan University of Science and Technology Xiangtan 411201 China4. Graduate University of Chinese Academy of Sciences Beijing 100190 China5. Nanjing R&D Center Huawei Technologies Nanjing 210012 China6. China Academy of Telecommunication Research of MIIT Beijing 100191 China7. China Mobile Research Institute Beijing 100053 China

Peer-to-peer (P2P) based content distribution systems have emerged as the main form for content distribution on the Internet,which can greatly reduce the distribution cost of content providers and improve the overall system ***,the mismatch between the overlay and underlay networks causes large volume of redundant traffic,which intensifies the tension between P2P content providers and ***,how to efficiently use network resources to reduce the traffic burden on the ISPs is crucial for the sustainable development of P2P *** paper surveys the state-of-art P2P traffic optimization technologies from three perspectives:P2P cache,locality-awareness and data *** details,comparison between these technologies and their applicabilities are presented,followed by a discussion of the issues that remain to be addressed and the direction of future content distribution research.

关键词： P2P traffic localization P2P traffic optimization P2P cache locality-awareness network coding content-centric network

Reduction of Coercivity of Fe-N Soft Magnetic Film by Heat Treatment

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Journal of Materials science & technology 2003年第5期19卷 491-494页

作者： Dan LI, Yousong GU, Xiangrong CHANG, Fushen LI, Lijie QIAO and Zhongzhuo TIANDepartment of Materials Physics, university of science & technology beijing, beijing 100083, china Department of Materials Physics University of Science and Technology Beijing Beijing 100083 China

200 nm thick Fe-N magnetic thin films were deposited on glass substrates by RF sputtering. The as-deposited films have high saturation magnetization but their coercivity is also higher than what is needed Therefore it is very important to reduce coercivity. The samples were vacuum annealed at 250℃ under 12000 A/m magnetic field. When the N content was in the range of 5-7 at. pct, the thin films consisted of α' +α' after heat treatment and had excellent soft magnetic properties of 4.Ms=2.4.T, HC 4.Ms=2.2 T, HC <80 A/m. The properties of the films meet the need of a recording head material used in the dual-element GMR/inductive heads.

关键词： Fe-N Soft magnetic film Coercivity

EFFECT OF Cr ADDITION ON MICROSTRVCTURES AND MECHANICAL PROPERLIES OF β-NiAl ALLOYS

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Acta Metallurgica Sinica(English Letters) 1999年第2期12卷 173-180页

作者： W.H. Tian S.L. Hu and M. Nemoto(1) Department of Materials Physics, university of science and technology beijing, beijing 100083, china 2) Department of Materials Forming, university of science and technology beijing, beijing 100083, china 3) Department Univ of science and technology Beijing Beijing China

The effect of Cr addition on the microstructures and mechanical properties of NiAl inermetallic alloys containing 4.to 8 mol% Cr has been characterized. It is shown that Cr is not only an efficient soild solution strengthener in NiAl, it is also an efficient precipitation Strengthener by fine dispersion of α-Cr particles. Transmission electron microscope observations have revealed that fine spherical particles of α-Cr appeared homogeneously in the NiAl matrix by aging at temperatures around 1073K after solution annealing at 1563K. The aging behavior was investigated by microhardness measurements and the temperature dependence of the yield stress of NiAl containing α-Cr particles was investigated by compression tests over the tempemture range from 298 to 1173K. NiAl alloys happened appreciably by the precipitation of α-Cr *** bypass the particles during deformation and typical Orowan loops were observed surrounding the α-Cr particles after deformation. Although the dispersion Of α-Cr particles increases the yield strength of NiAl at intermediate temperutre, the strength decreases appreciably at higher temperatures.

关键词： NiAl age-hardening precipitate deformation mechanism microstructure

Weighted estimation of single index models with right censored responses

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science china Mathematics 2011年第3期54卷 479-514页

作者： WANG YanHua1, LI XiaYan2, WANG QiHua3 & HE ShuYuan4.1School of sciences, beijing Institute of technology, beijing 100081, {4. 2Department of Mathematics, university of science and technology of {4., Hefei 230026, {4. 3Chinese Academy of Mathematics and System science, beijing 100080, {4. 4.chool of Mathematical sciences, Capital Normal university, beijing 10004., {4. 1. School of sciences Beijing Institute of Technology Beijing 100081 China2. Department of Mathematics University of Science and Technology of China Hefei 230026 China3. Chinese Academy of Mathematics and System Science Beijing 100080 China4. School of Mathematical Sciences Capital Normal University Beijing 100048 China

In this paper, the unknown link function, the direction parameter, and the heteroscedastic variance in single index models are estimated by the random weight method under the random censorship, respectively. The central limit theory and the convergence rate of the law of the iterated logarithm for the estimator of the direction parameter are derived, respectively. The optimal convergence rates for the estimators of the link function and the heteroscedastic variance are obtained. Simulation results support the theoretical results of the paper.

关键词： single index models random censorship central limit theorem law of the iterated logarithm weighted least squares unknown link function

A novel logic-based automatic approach to constructing compliant security policies

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science china(information sciences) 2012年第1期55卷 149-164页

作者： BAO YiBao1,2,4.YIN LiHua1,FANG BinXing 1,3&GUO Li 1 1Institute of Computing technology,Chinese Academy of sciences,beijing 100190,china 2Institute of Electronic technology,information Engineering university,Zhengzhou 4.0004.china 3beijing university of Posts and Telecommunications,beijing 100190,china 4.raduate university,the Chinese Academy of science,beijing 10004.,china 1. Institute of Computing technology Chinese Academy of Sciences Beijing 100190 China2. Institute of Electronic Technology Information Engineering University Zhengzhou 450004 China4. Graduate University the Chinese Academy of Science Beijing 100049 China3. Beijing University of Posts and Telecommunications Beijing 100190 China

It is significant to automatically detect and resolve the incompliance in security *** existing works in this field focus on compliance verification,and few of them provide approaches to automatically correct the incompliant security *** paper proposes a novel approach to automatically transform a given security policy into a compliant *** security policy Π and delegation policy M declared by logic programs,the approach automatically rewrites Π into a new one ΠM which is compliant with M and is readable by the *** prove that the algorithm is sound and complete under noninterference ***,we show that the security policy query evaluation algorithm with conflict and unsettlement resolution still works very well on Π*** approach is automatic,so it doesn't require a administrator with excess *** this sense,our proposal can help us to save much manpower resource in security management and improves the security assurance abilities.

关键词： security policy rewriting logic program compliance

Carbon Nitride Films Deposited on Pt Substrates byMicrowave Plasma Chemical Vapor Deposition

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International Journal of Minerals,Metallurgy and Materials 2000年第1期14卷 42-44页

作者： Yongping Zhang Yousong Gu Xiangrong Chang Zhongzhuo Tian Dongxia Shi Xiufang Zhanga Lei Yuan Material science and Engineering School, university of science and technology {4., {4. 100083, china {4. Laboratory of Vacuum Physics, Institut Material science and Engineering School University of Science and Technology Beijing Beijing 100083 China beijing Laboratory of Vacuum Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China

Carbon nitride thin films have been synthesized on polycrystalline Pt substrates using microwave plasma chemical vapor de- position (MPCVD) technique. The N/C atomic ratio is close to the stoichiometric value 1.33 of C_3N_4. The experimental X-ray diffraction spectra contain all the strong peaks of α-C_3N_4.and β -C_3N_4. The films are a mixture of α-C_3N_4.and β -C_3N_4. The observed Raman and FT- IR spectra support the existence of C-N covalent bond in carbon nitride compound. The bulk modulus detected by Nano II nanoindentor is up to 34. GPa.

关键词： carbon nitride MPCVD, thin film deposition

Comment on “Evolution model of the earth's limited expanding” from comparative planetology

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Chinese science Bulletin 2001年第17期46卷 1495-1496页

作者： SHI YaolinGraduate School, university of science and technology of china, Chinese Academy of sciences, beijing 100039, china Graduate School University of Science and Technology of China Chinese Academy of Sciences Beijing China

In the article 'Evolution Model of the Earth’s Limited Expanding' published in Volume 4. Number (4. of Chinese science Bulletin[1], the author suggests that the earth expands according to a law R(t) = R0+A(1 -exp(β(t-ts))) (remark: this formula was mistakenly printed as R(t) = R0 + Aexp(β(t-ts)) in the and formula (12) of the text of ref. [1]). According to ref. [1], the earth was formed 4.6 billion years ago. After 0.3 billion years from its birth (ts), it started expansion from an initial radius R0 of 4.51 km, and may reach a final maximum radius of R0+A = 6511 km. In the 4.6 billion years history, the radius of the earch has increased by 1720 km, or the density decreased from 14.00 km/m3 (2.57 times the present density) to 5520 kg/m3 within the latest 4.3 billion years.

关键词： from comparative planetology Evolution model of the earth’s limited expanding

An Application of Optimal Preview Control in Terrain Following System

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Journal of Systems Engineering and Electronics 2002年第1期13卷 21-26页

作者： Li Dongmei Dept. of Precision Instrument and Mechanics, tsinghua university, beijing 100084, P.R.china Zhou Di, Hu Zhenkun & Hu Hengzhang Dept. of Control {4. and Engineering, Harbin Institute of technology, Harbin 150001, P.R.china Dept. of Precision Instrument and Mechanics Tsinghua University Beijing 100084 P. R. China Dept. of Control science and Engineering Harbin Institute of Technology Harbin 150001 P. R. China

An optimal preview method is applied to the design of terrain following controller for cruise missile. In this method, tracking errors and control increments are both considered in the quadratic cost function. Integrating the general optimal servo system with a preview feedforward compensation that feeds forward future command and future disturbance produces an optimal preview servo system. In the terrain following system, the flight altitude of the cruise missile is a command signal, and its future information can be known apriori. Hence, we have designed a terrain following controller with a basic state feedback and a feedforward compensation for future altitude information. Simulation results show that the performance of the terrain following system with such an optimal preview controller has been improved dramatically.

关键词： Cruise missile Terrain following Preview control Optimal control Feedforward compensation.