检索结果-南通市图书馆

Wave decomposition phenomenon and spectrum evolution over submerged bars

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2009年第3期28卷 82-92页

作者： LI Benxia YU Xiping national Marine Environmental Forecasting center State Oceanic Administration Beijing 100081China Department of Hydraulic Engineering Tsinghua University Beijing 100084 China

Wave decomposition phenomenon and spectrum evolution over submerged bars are investigated by a previously developed numerical model. First, the computed free surface displacements of regular waves at various locations are compared with the available experimental data to confirm the validity of the numerical model, and satisfactory agreements are obtained. In addition, variations of decomposition characteristics with incident wave parameters and the change of energy spectrum for regular waves are also studied. Then the spectrum evolution of irregular waves over submerged bars, as well as the influence of incident peak wave period and the steepness of the front slope of the bar on spectrum evolution, is investigated. Wave decomposition and spectral shape are found to be significantly influenced by the incident wave conditions. When the upslope of the bar becomes 1：2, the length of the slope becomes shorter and will not benefit the generation of high frequency energy, so spectrum evolution is not significant.

关键词： wave decomposition spectrum evolution nonlinear waves irregular waves submerged bars

Protein Product Encoded by a Human Novel Gene E9730 Enhances AP-1 Activity through Interacting with Jab1

在线全文

学校读者我要写书评

暂无评论

Acta Biochimica et Biophysica Sinica 2004年第1期36卷 11-15页

作者： Zhao-Qing WANG, Han-Dong WEI, and Fu-Chu HE(Department of System Biology, beijing Institute of Radiation Medicine, Chinese Human national center at beijing, beijing 100850, china) Department of System Biology Beijing Institute of Radiation Medicine Chinese Human National Center at Beijing Beijing 100850 China

A novel human gene, named E9730 (a clone number of fetal liver cDNA library), has been identified from more than 14,000 expressed sequence tags (ESTs) based on our large scale sequencing of human fetal liver cDNA libraries. Although sequencing of this novel human gene indicates that it is a leucine zipper protein, the function of E9730 and its homologous genes among species is unknown yet. To find out physiological functional clue of E9730, the yeast two-hybrid system was used to screen the E9730-interac-ting protein(s), and one clone containing a cDNA insert with almost the entire coding sequence (amino acids 39-335) of human Jabl (Jun-activating domain binding protein 1) that interacted specifically with E9730 was identified. A specific association between Jabl and E9730 was shown by co-immunoprecipitation and co-localization experiments. Furthermore, E9730 appeared to enhance Jab 1 -induced AP-1 activity in a concentration-dependent manner and Jabl may be involved in the intracellular signaling trans

关键词： human E9730 gene CSN5/Jabl protein-protein interaction signaling transduction

Principle and application of three-band gradient difference vegetation index

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 2005年第2期48卷 241-249页

作者： TANG Shihao, ZHU Qijiang, WANG Jindi, ZHOU Yuyu & ZHAO Feng Research center for Remote Sensing and GIS, Department of Geography, beijing Normal University, beijing 100875, china national Satellite Meteorological center, china Meteorological Administration, beijing 100081, china 1. Research center for Remote Sensing and GIS Department of Geography Beijing Normal University 100875 Beijing China 2. national Satellite Meteorological center China Meteorological Administration 100081 Beijing China

Vegetation index is a simple, effective and experiential measurement of terrestrial vegetation activity, and plays a very important role in qualitative and quantitative remote sensing. Aiming at shortages of current vegetation indices, and starting from the analysis of vegetation spectral characteristics, we put forward a new vegetation index, the three-band gradient difference vegetation index (TGDVI), and established algorithms to inverse crown cover fraction and leaf area index (LAI) from it. Theoretical analysis and model simulation show that TGDVI has high saturation point and the ability to remove the influence of background to some degree, and the explicit functional relation with crown cover fraction and LAI can be established. Moreover, study shows that TGDVI also has the ability to partly remove the influence of thin cloud. Experiment in the Shunyi District, beijing, china shows that reasonable result can be reached using the vegetation index to retrieve LAI. We also theoretically analyzed the reason why the normalized difference vegetation index (NDVI) owns the low saturation point, and show that it is determined by the definition of NDVI and the characteristic of vegetation spectra, and is unavoidable to some degree. Meanwhile, through model simulation, we also indicate that the relationship between simple ratio vegetation index (SR) and LAI closes to a piecewise linear one instead of a linear one, which is mainly caused by the influence of background and different change rates of reflectance in red and infrared bands with LAI increasing.

关键词： vegetation index, remote sensing, LAI, crown cover fraction, remote sensing inversion.

A New hcp Phase Formed in the Ni-Nb System during Ion-beam-assisted Deposition

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2004年第5期20卷 577-579页

作者： Bin ZHAO, Kuiwei GENG, Fei ZENG and Feng PANLaboratory of Advanced Materials, Department of Materials Science and Engineering, tsinghua University, beijing 100084, china Lab. of Adv. Mat. Dept. of Mat. Sci. and Eng. Tsinghua Univ. Beijing 100084 China

The Ni80Nb20 films were prepared by ion beam assisted deposition (IBAD) with various Ar+ ion energies. A phase evolution of fcc→amorphous→Ni+Nb→Ni+hcp was observed with the increasing of ion beam energy from 2 keV to 8 keV. When bombarded by Ar+ ions of 8 keV during deposition, a new crystalline phase with hcp structure was obtained, of which the lattice parameters are a=0.286 nm and c=0.483 nm, different from those of the similar A3B-type hcp phase previously reported. The experimental results were discussed in terms of thermodynamics and restricted kinetic conditions in the far-from-equilibrium process of IBAD. The formation of hep phase may also be related to the valence electron effect.

关键词： Hcp phase Ni-Nb Ion beam assisted deposition Thermodynamics Valence electron effect

Relationship between the Asian-Pacific oscillation and the tropical cyclone frequency in the western North Pacific

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2008年第3期51卷 380-385页

作者： ZHOU BoTao1, CUI Xuan2 & ZHAO Ping3 1 Laboratory for Climate Studies, national Climate center, china Meteorological Administration, beijing 100081, china 2 national Meteorological center, china Meteorological Administration, beijing 100081, china 3 Chinese Academy of Meteorological Sciences, china Meteorological Administration, beijing 100081, china 1. Laboratory for Climate Studies National Climate Center China Meteorological Administration Beijing 100081 China 2. national Meteorological center China Meteorological Administration Beijing 100081 China 3. Chinese Academy of Meteorological Sciences China Meteorological Administration Beijing 100081 China

The relationship between the Asian-Pacific oscillation (APO) and the tropical cyclone frequency over the western North Pacific (WNP) in summer is preliminarily investigated through an analysis of ob- served data. The result has shown clearly that APO is significantly and positively correlated to the tropical cyclone frequency in the WNP. If APO is above (below) the normal in summer, more (less) tropical cyclones will tend to appear in the WNP. The present study also addresses the large-scale at- mospheric general circulation changes underlying the linkage between APO and the WNP tropical cy- clone frequency. It follows that a positive phase of summer APO is concurrent with weakened as well as northward and eastward located western Pacific subtropical high (WPSH), low-level convergence and high-level divergence, and reduced vertical zonal wind shear in the WNP, providing favorable envi- ronment for the tropical cyclone genesis, and thus more tropical cyclones will come into being, and vice versa.

关键词： Asian-Pacific oscillation western North Pacific tropical cyclone atmospheric circulation

Electric-stimulus rate encoding algorithm of Mandarin tonal information in cochlear implant

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12期16卷 1315-1321页

作者： GUAN Tian~1, GONG Qin~1 and YE Datian~2**(1. Department of Biomedical Engineering, tsinghua University, beijing 100084, china 2. Research center of Biomedical Engineering, Graduate School at Shenzhen, tsinghua University, Shenzhen 518055, china) [a]Department of Biomedical Engineering Tsinghua University Beijing China [b]Research center of Biomedical Engineering Graduate School at Shenzhen Tsinghua University Shenzhen China

The modern multi-channel cochlear implants usually extract and encode the temporal envelope cues. This kind of algorithms can hardly satisfy the users who speak tonal languages, such as Mandarin. Many studies have tried to enhance the recognition ability of Mandarin through encoding tonal information and made suggestions to frequency-modulate the fixed pulse-rate carrier with the extracted tonal information based on the rate-pitch theory in electric hearing. However, how to encode and deliver the tonal information such as F_0by changing electric-stimulus rate has not got further study in clinical electric-stimulus mode. The present paper focuses on this matter by piecewise calculating the appreciable electric-stimulus rates. Then an electric-stimulus encoding algorithm of Mandarin tone is brought forward and testified through acoustic simulations. Such conclusion can be drawn that this algorithm of electric-stimulus rate could convey tonal information well and help to enhance the Mandarin speech recognition ability.

关键词： cochlear implant tone fundamental frequency electric-stimulus rate.

The numerical simulation of Pacific Ocean circulation with five-level model

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 1993年第3期12卷 395-404页

作者： Xing Runan and Chao Jiping beijing Meteorological College, beijing 100081 china national Research center for Marine Environmental Forecasts, beijing 100081, china

A five-level oceanic primitive equation model has been developed. This model is integrated numerically with annual mean wind stress and heat flux at sea surface for 30 a. The ocean circulations tend to quasi-stability. The simulated results show that the computed annual mean currents and sea surface temperature agree well with the observations.

关键词： heat The numerical simulation of Pacific Ocean circulation with five-level model

PHASE EXTENSION AND STRUCTURE ANALYSIS BY THE MAXIMUM ENTROPY METHOD

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1998年第4期11卷 241-254页

作者： G.B.Hu and Q.B.Yang (Department of Physics, Xiangtan University, Xiangtan 411105, china)(beijing Laboratory of electron microscopy, center for Condensed Matter Physics, The Chinese Academy of Sciences, P. O. Box 2724, beijing 100080, china) Xiangtan Univ Xiangtan China

Excellent results are obtained in structure analysis with jew phases of structure factors by the maximum-entropy method (MEM) for CaGaN PbCO3 and ReBe22 single crystals. The computation time and memory space are minim... 详细信息

关键词： maximum entropy method structure analysis phase extension,symmetry

Effect of Heating Rate Before Tempering on Reversed Austenite in Fe-9Ni-C Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2012年第9期19卷 73-78页

作者： ZHANG Kun , TANG Di , WU Hui-bin ( national Engineering Research center of Advanced Rolling , University of Science and Technology beijing , beijing 100083 , china ) national Engineering Research center of Advanced Rolling University of Science and Technology Beijing Beijing 100083 China

The alloy was reheated to 580℃ for tempering at rates of 2 , 5 , 10 , 20 , and 40℃ / s , respectively , after *** amount , distribution , and stability of reversed austenite were investigated by X-ray diffraction ( XRD ) and electron back scatter diffraction ( EBSD ) .The microstructure and cryogenic impact energy were studied by scanning electron microscope ( SEM ), transmission electron microscope ( TEM ) and Charpy V-notch ( CVN ) *** results showed that when the sample was heated at 10℃ / s , the volume fraction of reversed austenite exhibited maximum of 8% ; the reversed austenite was uniform along all kinds of boundaries ; the reversed austenite contained higher concentration of carbon which enabled it to be more *** cryogenic toughness of the alloy was greatly improved when heated at 10℃ / s , as the fracture surface observation showed that it mainly fractured in ductile rupture mode , which was consistent with the results of cryogenic impact energy.

关键词： 9Ni steel heating rate reversed austenite cryogenic toughness