检索结果-南通市图书馆

From quantum spectra to classical orbits: Varying rectangular billiards

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2008年第8期18卷 927-930页

作者： Jun Lu * Department of Foundational Science, beijing Union university, beijing 100101, china Institute of Theoretical Physics, chinese academy of sciences, beijing 100080, china Department of Foundational Science Beijing Union University Beijing 100101 China Institute of Theoretical Physics Chinese Academy of Sciences Beijing 100080 China

The quantum-spectrum function is introduced by means of the eigenvalues and the eigenfunctions in the system of varying rectangular billiards. It is found that the Fourier transform of the quantum-spectrum function corresponds with the classical orbits in the system. These results give new evidence about the classical-quantum correspondence.

关键词： Quantum spectrum Classical-quantum correspondence Semiclassical physics

PLS path model building:A multivariate approach to land price studies-A case study in beijing

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2009年第11期19卷 1643-1649页

作者： Wenjie Wu~(a,b),Wenzhong Zhang~(a,*) a Institute of Geographic sciences and Natural Resources Research,CAS,beijing 100101,china b graduate university of chinese academy of sciences,beijing 100049,china Institute of Geographic sciences and Natural Resources Research CAS Beijing 100101 China graduate university of chinese academy of sciences Beijing 100049 China

Previous studies have revealed that statistical methods can be used to analyze land-leasing parcel ***,the conventional statistical methods used in land analysis have some limitations,especially in cases of limited observational *** this paper,with the help of geographic information system(GIS) techniques,a partial least squares(PLS) path model is applied to study the relationship between residential land prices and various determinants through a case study of beijing in *** a preliminary analysis,four latent variables are selected:accessibility of the workplace center,livability,traffic,and environment *** results show that the observation variables have a strong explanatory power for their corresponding latent variables,and the four latent variables have varying impacts on residential land *** the latent variables,accessibility to the workplace center has the strongest impact on the residential land price.

关键词： Land PLS path model GIS beijing

A new approach of cascade utilization of the chemical energy of fuel

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第5期16卷 518-523页

作者： HAN Wei, JIN Hongguang and LIN Rumou ( Institute of Engineering Thermophysics, chinese academy of sciences, beijing 100080, china graduate School of the chinese academy of sciences, beijing 100080, china) Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100080 China graduate School of the chinese academy of sciences Beijing 100080 China

The indirect release of chemical energy of fuel is investigated, and a new mechanism is proposed to identify the cascade utilization of chemical energy of fuel more clearly. Based on the concept of energy level, the internal phenomenon of the indirect chemical energy release is disclosed, and the equations of energy level describing the utilization of chemical energy and thermal energy during the indirect chemical energy release process are obtained. From theoretical analysis, we find that the superiority of the indirect chemical energy release of fuel comes from the cascade utilization of the fuel's chemical energy. Moreover, the cascade utilization of chemical energy is verified by the investigation of CRGT (chemically recuperated gas turbine). As a result, the thermal exergy obtained from the chemical energy release of fuel increases by 2 % -3 % . The results obtained here may help a deeper understanding of indirect chemical energy release of fuel and provide a theoretical basis for the synthesis of innovative energy systems.

关键词： chemically recuperated gas turbine methane/steam reforming chemical energy level cascade utilization.

Effects of the Biot and the squirt-flow coupling interaction on anisotropic elastic waves

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

chinese Science Bulletin 2000年第23期45卷 2130-2138页

作者： YANG Dinghui & ZHANG Zhongjie Department of Mathematical sciences, Tsinghua university, beijing 100084, china Institute of Geophysics, chinese academy of sciences, beijing 100101, china Department of Mathematical sciences Tsinghua University Beijing China Institute of Geophysics Chinese Academy of Sciences Beijing China

Considering the velocity anisotropy of the solid/fluid relative motion and employment of the BISQ theory based on the one-dimensional porous isotropic case, we establish a two-phase anisotropic elastic wave equation to simultaneously include the Biot and the squirt mechanisms in terms of both the basic principles of the fluid’s mass conservation and the elastic-wave dynamical equations in the two-phase anisotropic rock. Numerical results, while the Biot-flow and the squirt-flow effects are simultaneously considered in the transversely isotropic (Tl) poroelastic medium, show that the attenuation of the quasi P-wave and the quasi SV-wave strongly depend on the permeability anisotropy, and the attenuation behavior at low and high frequencies is contrary. Meanwhile, the attenuation and dispersion of the quasi P-wave are also affected seriously by the anisotropic solid/fluid coupling additional density.

关键词： two-phase anisotropy Biot flow squirt-flow elastic wave attenuation and dispersion BISQ model.

Myotoxic activity of a Gln-49 phospholipase A2 from Agkistrodon blomhoffii ussurensis snake venom

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第2期16卷 178-182页

作者： BAO Yongming, BU Pengcheng, YANG Jun, YANG Wei, JIA Peilin and AN Lijia (Department of Bioscience and Biotechnology, Dalian university of Technology, Dalian 116024, china Institute of Biophysics, chinese academy of sciences, beijing 100101, china graduate School of chinese academy of sciences, beijing 100039, china) Department of Bioscience and Biotechnology Dalian University of Technology Dalian 116024 China Institute of Biophysics chinese academy of sciences Beijing 100101 China graduate School of chinese academy of sciences Beijing 100039 China

A novel myotoxic protein phospholipase A2(PLA2), denoted as Gln49-PLA2, has been isolated from snake venom of Agkistrodon blomhoffii ussurensis, which has weak lethal effect and apparent anticoagulant activity, but lacks the PLA2 and hemorrha-genic activity. Gln49-PLA2 obviously increases of plasma creatine-kinase (CK) upon intramuscular injection in mice, suggesting that it may induce a dose-dependent myonecrosis. Histological studies also reveal morphological changes in mouse skeletal muscles, including extensive myonecrosis, hemorrhage and neutrophil infiltration in the treated animals. The myotoxic ability induced by Gln49-PLA2 can be partially inhibited by heparin.

关键词： snake venom phospholipase A2 Agkistrodon blomhoffii ussurensis myotoxic activity.

Compositions of heavy minerals in Northeastern china sandlands and provenance analysis

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 Earth sciences 2007年第11期50卷 1715-1723页

作者： XIE Jing1,2 & DING ZhongLi1 1 Institute of Geology and Geophysics, chinese academy of sciences, beijing 100029, china 2 graduate university of chinese academy of sciences, beijing 100049, china Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China graduate university of chinese academy of sciences Beijing China

Sand samples deposited since the Last Glacial Maximum (LGM) from the Hulun Buir, Horqin and Otin-dag sandlands were measured for their assemblages of heavy minerals and chemical compositions of detrital garnets and tourmalines. Heavy mineral assemblages of these three sandlands consist mainly of garnet, ilmenite, epidote and minor amphibole and magnetite. Garnets consist mainly of high Mg type-A ones (58% on average), and minor type-B ones. Toumalines are mainly composed of Mg-rich and minor Fe-rich ones. Compared with those of central-southern Mongolia and central Tarim, these three sandlands are derived from the Phanerozoic rocks of the Central Asian Orogenic Belt and the Archean and Paleoprotorozoic basement rocks of the North china Craton. Our results provide direct evidence that the present-day sands may be reworked from LGM ones. Differences of heavy mineral composi-tions occur between the samples of the three sandlands and Taklimakan Desert, indicating that the material of the western arid regions contributes little to the eastern sandlands.

关键词： heavy minerals,provenance,Northeastern china,garnet,tourmaline

ON THE CENTRAL RELAXING SCHEME Ⅱ: SYSTEMS OF HYPERBOLIC CONSERVATION LAWS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2001年第6期19卷 571-582页

作者： Hua-zhong Tang (School of Mathematical sciences, Peking university, beijing 100871, china) (LSEC,ICMSEC academy of Mathematics and Systems sciences, chinese academy of sciences, beijing 100080, china) School of Mathematical sciences Peking University Beijing 100871 China

This paper continues to study the central relaxing schemes for system of hyperbolic conservation laws, based on the local relaxation approximation. Two classes of relaxing systems with stiff source term are introduced to approximate system of conservation laws in curvilinear coordinates. Based on them, the semi-implicit relaxing schemes are con- structed as in [6, 12] without using any linear or nonlinear Riemann solvers. Numerical experiments for one-dimensional and two-dimensional problems are presented to demon- strate the performance and resolution of the current schemes.

关键词： Hyperbolic conservation laws The relaxing system The central relaxing schemes The Euler equations.

Models and methods for precise determination of ionospheric delay using GPS

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2期17卷 187-196页

作者： YUAN Yunbin, HUO Xingliang and OU Jikun ( Institute of Geodesy and Geophysics, chinese academy of sciences, Wuhan 430077, china graduate university of chinese A-cademy of sciences, beijing 100039, china) Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China graduate university Chinese Academy of Sciences Beijing 100039 China

The basic principles and methods for precisely determining ionospheric delays in GPS observations are introduced and discussed. Various methods and models for fitting ionospheric delays based on GPS are compared and a... 详细信息

关键词： GPS ionospheric delay atmosphere modeling precise GPS positioning.

SUSPENDED SEDIMENT TRANSPORT IN THE OFFSHORE NEAR YANGTZE ESTUARY

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2008年第3期20卷 373-381页

作者： CHEN Bin WANG Kai Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China graduate university of the chinese academy of sciences Beijing 100039 China

Based on the Estuarine, Coastal and Ocean Modeling System with Sediments （ECOMSED） model, a 3-D hydrodynamic-transport numerical model was established for the offshore area near the Yangtze Estuary in the East china Sea .The hydrodynamic module was driven by tide and wind. Sediment module included sediment resuspension, transport and deposition of cohesive and non-cohesive sediment. The settling of cohesive sediment in the water column was modeled as a fimction of aggregation （flocculation） and deposition. The numerical results were compared with observation data for August, 2006. It shows that the sediment concentration reduces gradually from the seashore to the offshore area. Numerical results of concentration time series in the observation stations show two peaks and two valleys, according with the observation data. It is mainly affected by tidal current. The suspended sediment concentration is related to the tidal current during a tidal cycle, and the maximum concentration appears 1 h-4 h after the current maximum velocity has reached.

关键词： Yangtze Estuary sediment concentration sediment transport