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Propagation characteristics of converted refracted wave and its application in static correction of converted wave

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Science china Earth Sciences 2008年第S2期51卷 226-232页

作者： LIU Yang1,2 & WEI XiuCheng3 1 State Key Laboratory of Petroleum Resource and Prospecting,china University of Petroleum,beijing 102249,china 2 CNPC Geophysical Exploration Key Laboratory,china University of Petroleum,beijing 102249,china 3 Exploration and Production Research institute,SINOPEC,beijing 100083,china china Univ Petr State Key Lab Petr Resource & Prospecting Beijing 102249 Peoples R China china Univ Petr CNPC Geophys Explorat Key Lab Beijing 102249 Peoples R China SINOPEC Explorat & Prod Res Inst Beijing 100083 Peoples R China

Three-component seismic exploration through P-wave source and three-component geophone is an effective technique used in complicated reservoir exploration. In three-component seismic exploration data processing,one of the difficulties is static correction of converted wave. This paper analyzes propagation characteristics of non-converted and converted refracted waves,and discovers a favor-able condition for the formation of converted refracted wave,i.e. the velocity of overlaying medium S wave is much lower than that of underlying medium S wave. In addition,the paper proposes the static correction method of converted wave based on PPS converted refracted wave,and processes the real three-component seismic data with better results of static correction of converted wave.

关键词： PPS converted refracted wave converted wave static correction

Direct CP violation in hadronic B decays

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Science china(Physics,Mechanics & Astronomy) 2006年第3期49卷 357-366页

作者： HONG Bihai1,2 & Lü Caidian3 1. Department of Physics, Lishui University, Lishui 323000,china 2. Department of Physics, Shanghai Jiaotong University, Shanghai 200030, china 3. institute of High energy Physics, beijing 100049,china Department of Physics Lishui University Lishui 323000 China Department of Physics Shanghai Jiaotong University Shanghai 200030 China institute of High energy Physics Beijing 100049 China

There are different approaches for the hadronic B decay calculations, recently. In this paper, we upgrade three of them, namely factorization, QCD factorization and the perturbative QCD approach based on kT factorization, using new parameters and full wave functions. Although they get similar results for many of the branching ratios, the direct CP asymmetries predicted by them are different, which can be tested by recent experimental measurements of B factories.

关键词： CP violation hadronic B decay factorization.

Tungsten-182 Mssbauer experiments at liquid nitrogen temperature

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Chinese Science Bulletin 2001年第9期46卷 732-734页

作者： HUANG Runsheng, LIU Bing, ZHANG Jinrong, LIU Cong & GAO Xuekui1. Physics Department of Nanjing University, Nanjing 210093, china 2. china institute of atomic energy, beijing 102.13, china Physics Department of Nanjing University Nanjing China china institute of atomic energy Beijing China

A good 182Ta Mossbauer source and an apparatus designed specially were made. 182W transmission Mossbauer experiments were successfully carried out, both of the source and absorber at liquid nitrogen temperature. It wa... 详细信息

关键词： Mossbauer effect 182W Mossbauer effect.

Systematic distortion in cosmic microwave background maps

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Science china(Physics,Mechanics & Astronomy) 2009年第5期52卷 804-808页

作者： LIU Hao 1,3 &LI TiPei 1,2 1Key Laboratory of Particle Astrophysics,institute of High energy Physics,Chinese Academy of Sciences,beijing 100049,china 2Center for Astrophysics,Tsinghua University,beijing 100084,china 3 Graduate University of Chinese Academy of Sciences,beijing 100049,china Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Center for Astrophysics Tsinghua University Beijing 100084 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

To minimize instrumentally the induced systematic errors,cosmic microwave background(CMB)anisotropy experiments measure temperature differences across the sky using pairs of horn antennas, temperature map is recovered from temperature difference obtained in sky survey through a map-making *** inspect and calibrate residual systematic errors in the recovered temperature maps is important as most previous studies of cosmology are based on these *** analyzing pixel-ring coupling and latitude dependence of CMB temperatures,we find notable systematic devia- tion from CMB Gaussianity in released Wilkinson Microwave Anisotropy Probe(WMAP)*** detected deviation cannot be explained by the best-fit LCDM cosmological model at a confidence level above 99%and cannot be ignored for a precision cosmology study.

关键词： cosmology cosmic microwave background methods data analysis

Electronic structure and magnetism of R(Fe,Si)_(12) (R=Y,Nd)

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Science china(Physics,Mechanics & Astronomy) 2006年第2期49卷 195-202页

作者： SUN Guang’ai1, CHEN Bo1, DU Honglin2, FAN Zhijian1, GAO Tao3 & QI Xinhua31. institute of Nuclear Physics and Chemistry, china Academy of Engineering Physics, Mianyang 621900, china 2. Department of physics, Peking university, beijing 100871, china 3. institute of atomic and Molecular Physics, Sichuan University, Chengdu 610065, china 1. institute of Nuclear Physics and Chemistry China Academy of Engineering Physics Mianyang 621900 China 2. Department of physics Peking university Beijing 100871 China 3. institute of atomic and Molecular Physics Sichuan University Chengdu 610065 China

The newly developed full-potential linearized augmented plane wave (LAPW) and local orbitals (lo) based on standard APW methods are briefly introduced, and the structure and magnetic properties of R(Fe, Si)12 compounds (R = Y, Nd) are calculated using the method. The distribution of Si at different sites is analyzed based on total energy of one crystal unit with structure having been optimized. The characters of magnetic mo-ments, total density of states (TDOS) and partial density of states (PDOS) for different crystal sites Si occupies are obtained and analyzed. The results show that the total mag-netic moments of RFe10Si2 (R = Y, Nd) are larger than those of RFe10M2 (M = Ti, V, Cr, Mn, Mo and W) and the hybridization mechanism is seen as follows. Si(8j) reduce the mag-netic moments of Fe at three sites, however, Si(8f) mainly reduce the magnetic moments of Fe(8i) and Fe(8j) atoms. The Curie temperature is markedly enhanced by the introduc-tion of Si atoms according to spin fluctuation of DOS at Fermi level.

关键词： (L)APW+lo method R(Fe Si)12(R = Y Nd) magnetic moment Density of state.

Catalytic protection of stannous ion by ascorbic acid in diphosphonic acids solutions

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Nuclear Science and Techniques 1998年第2期9卷 121-123页

作者： Liu Guo-Zheng Liu Fei Miao Zeng-Xing Wang Yi-Shan and Fang Ji-Dong (Isotope Department, china institute of atomic energy, beijing 102.13) Isotope Department China Institute of Atomic Energy Beijing 102413 China

The protective ability of ascorbic acid(Vc) on stannous ion and the influence of light irradiation on the stability of stannous ion in diphosphonate medium at pH=5 have been examined in order to attain minimal loss of stannous ion during the production of lyophilized radiopharmaceutical *** sum of stanous ion and Vc was determined with iodometric *** was shown that the protective ability of Vc was still strong at Vc concentration much lower than that of stannous ion and the illumination by fluorescent lamp was unfavorable to the stability of stannous *** change of pH in the range 3-9 did not affect the action of Vc significantly.

关键词：锡离子稳定性骨造影工具

A SIMPLE WAY CONSTRUCTING SYMPLECTICRUNGE-KUTTA METHODS

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Journal of Computational Mathematics 2000年第1期18卷 61-68页

作者： Geng Sun(institute of Mathematics, Academia Sinica, beijing 100080, china) 中科院数学所北京 100080

Presents a study which derived a way of constructing symplectic methods with the help of symplecticity conditions of partitioned Runge-Kutta methods. Classes of symplectic Runge-Kutta methods; Relationship between Run... 详细信息

关键词： symplecticity condition partitioned Runge-Kutta method

Design of secure operating systems with high security levels

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Science in china(Series F) 2007年第3期50卷 399-418页

作者： QING SiHan1,2 & SHEN ChangXiang3 1 institute of Software, Chinese Academy of Sciences, beijing 100080, china 2 School of Software and Microelectronics, Peking University, beijing 102600, china 3 institute of Computing Technology, Navy, beijing 100841, china 1. institute of Software Chinese Academy of Sciences Beijing 100080 China 2. School of Software and Microelectronics Peking University Beijing 102600 China 3. institute of Computing Technology Navy Beijing 100841 China

Numerous Internet security incidents have shown that support from secure operating systems is paramount to fighting threats posed by modern computing environments. Based on the requirements of the relevant national and international standards and criteria, in combination with our experience in the design and development of the ANSHENG v4.0 secure operating system with high security level （hereafter simply referred to as ANSHENG OS）, this paper addresses the following key issues in the design of secure operating systems with high security levels： security architecture, security policy models, and covert channel analysis. The design principles of security architecture and three basic security models： confidentiality, integrity, and privilege control models are discussed, respectively. Three novel security models and new security architecture are proposed. The prominent features of these proposals, as well as their applications to the ANSHENG OS, are elaborated. Cover channel analysis （CCA） is a well-known hard problem in the design of secure operating systems with high security levels since to date it lacks a sound theoretical basis and systematic analysis approach. In order to resolve the fundamental difficulties of CCA, we have set up a sound theoretical basis for completeness of covert channel identification and have proposed a unified framework for covert channel identification and an efficient backward tracking search method. The successful application of our new proposals to the ANSHENG OS has shown that it can help ease and speedup the entire CCA process.

关键词： secure operating systems with high security levels architecture security model covert channel analysis

Kinetics study on the dissolution of UO_2 particles by microwave and conventional heating in 4 mol/L nitric acid

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Science china Chemistry 2008年第7期51卷 700-704页

作者： ZHAO YunFeng & CHEN Jing institute of Nuclear and New energy Technology, Tsinghua University, beijing 102201, china institute of Nuclear and New energy Technology Tsinghua UniversityBeijing 102201China

The dissolution of UO2 particles in 4 mol·L-1 nitric acid medium at temperatures of 90-110℃ by mi- crowave heating and conventional heating has been investigated, respectively. It is found that the dissolution ratios of UO2 particles by microwave heating were 10%-40% higher than that by conven- tional heating. Kinetics research shows that the dissolution of UO2 particles in 4 mol·L-1 nitric acid is controlled by the diffusion control model for microwave heating and by the surface reaction control model for conventional heating. The diffusion control model for the dissolution of UO2 particles by mi- crowave heating could be explained by the diffuseness on the surface of UO2 particles.

关键词： uranium dioxide nitric acid dissolution microwave heating