检索结果-南通市图书馆

Higher order bulk characteristic parameters of asymmetric nuclear matter

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(Physics,Mechanics & Astronomy) 2011年第S1期54卷 124-129页

作者： CHEN LieWen1,2 1Department of Physics, shanghai Jiao Tong University, shanghai 200240, china 2center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000, china 1. Department of Physics Shanghai Jiao Tong University Shanghai 200240 China 2. center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator Lanzhou 730000 China

The bulk parameters characterizing the energy of symmetric nuclear matter and the symmetry energy defined at normal nuclear density ρ0 provide important information on the equation of state (EOS) of isospin asymmetric nuclear matter. While significant progress has been made in determining some lower order bulk characteristic parameters, such as the energy E0(ρ0) and incompress ibility K0 of symmetric nuclear matter as well as the symmetry energy Esym(ρ0) and its slope parameter L, yet the higher order bulk characteristic parameters are still poorly known. Here, we analyze the correlations between the lower and higher order bulk char acteristic parameters within the framework of Skyrme Hartree-Fock energy density functional and then estimate the values of some higher order bulk characteristic parameters. In particular, we obtain J0 = (-355±95) MeV and I0 = (1473±680) MeV for the third order and fourth-order derivative parameters of symmetric nuclear matter at ρ0 and Ksym = (-100 ± 165) MeV, Jsym = (224 ± 385) MeV, Isym = (-1309 ± 2025) MeV for the curvature parameter, third-order and fourth-order derivative parameters of the symmetry energy at ρ0, using the empirical constraints on E0(ρ0), K0, Esym(ρ0), L, and the isoscalar and isovector nucleon effective masses. Furthermore, our results indicate that the three parameters E0(ρ0), K0, and J0 can reasonably characterize the EOS of symmetric nuclear matter up to 2ρ0 while the symmetry energy up to 2ρ0 can be well described by Esym(ρ0), L, and Ksym.

关键词： equations of state of nuclear matter forces in hadronic systems and effective interactions symmetry energy nuclear density functional theory and extensions asymmetric matter neutron matter

Large-eddy simulations and vortex structures of turbulent jets in crossflow

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2007年第1期50卷 118-132页

作者： GUAN Hui1,2 & WU ChuiJie2 1 School of Mechanical and Power Engineering,East china University of Science and Technology,shanghai 200237,china 2 research center for Fluid Dynamics,PLA University of Science and Technology,Nanjing 211101,china 1. School of Mechanical and Power Engineering East China University of Science and Technology Shanghai 200237 China 2. research center for Fluid Dynamics PLA University of Science and Technology Nanjing 211101 China

Using the method of large-eddy simulation, the 3-dimensional turbulent jets in crossflow with stream-wise and transverse arrangements of nozzle are simulated, emphasizing on the dynamical process of generation and evolution of vortex structures in these flows. The results show that the basic vortex structures in literatures, such as the counter-rotating vortex pair, leading-edge vortices, lee-side vortices, hanging vortices, kidney vortices and anti-kidney vortices, are not independent physical substances, but local structures of the basic vortex structure of turbulent jets in crossflow-the 3-D stretching vortex rings originating from the orifice of the nozzle, which is discovered in this study. Therefore, the most important large-scale structures of turbulent jets in crossflow are unified to the 3-D vortex rings which stretch and twist in stream-wise and swing in transverse directions. We also found that the shedding frequencies of vortex rings are much lower than the one corresponding to the appearance of leading-edge and lee-side vortices in the turbulent jets.

关键词： turbulent jet in crossflow coherent structure large-eddy simulation

Understanding SARS with Wolfram Approach

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 1-10页

作者： Da-Wei LI, Yu-Xi PAN, Yun DUAN, Zhen-De HUNG, Ming-Qing XU, and Lin HE ( Bio-X Life Science research center, shanghai Jiao Tong University, shanghai 200030, china Institute for Nutritional science, the Chinese Academy of Sciences, shanghai 200031, china ) Bio-X Life Science research center Shanghai Jiao Tong University Shanghai 200030 China.

Stepping acquired immunodeficiency syndrome (AIDS), severe acute respiratory syndrome (SARS) as another type of disease has been threatening mankind since late last year. Many scientists worldwide are making great efforts to study the etiology of this disease with different approaches. 13 species of SARS virus have been sequenced. However, most people still largely rely on the traditional methods with some disadvantages. In this work, we used Wolfram approach to study the relationship among SARS viruses and between SARS viruses and other types of viruses, the effect of variations on the whole genome and the advantages in the analysis of SARS based on this novel approach. As a result, the similarities between SARS viruses and other coronavirusxes are not really higher than those between SARS viruses and non-coronaviruses.

关键词： genome sequence SARS visualization Wolfram approach

PREDICTION OF ACOUSTIC PERFORMANCE IN EXPANSION CHAMBER MUFFLERS WITH MEAN FLOW BY FINITE ELEMENT METHOD

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 Journal of Mechanical Engineering 2003年第3期16卷 292-295,304页

作者： Liu YadongLi CongxinRuan XueyuNational Die & Mold CAD Engineeringresearch center,shanghai Jiaotong University,shanghai 200030, china National Die & Mold CAD Engineering research center Shanghai Jiaotong University Shanghai 200030 China

The equation of wave propagation in a circular chamber with mean flow is obtained. Computational solution based on finite element method is employed to determine the transmission loss of expansive chamber. The effect of the mean flow and geometry (length of expansion chamber and expansion ratio)on acoustic attenuation performance is discussed, the predicted values of transmission loss of expansion chamber without and with mean flow are compared with those reported in the literature and they agree well. The accuracy of the prediction of transmission loss implies that finite element approximations are applicable to a lot of practical applications.

关键词： Wave equation Finite element method Exhaust mufflers Acoustic characteristics

EMMA:An Efficient Massive Mapping Algorithm Using Improved Approximate Mapping Filtering

在线全文

学校读者我要写书评

暂无评论

Acta Biochimica et Biophysica Sinica 2006年第12期38卷 857-864页

作者： Xin ZHANG~1 Zhi-Wei CAO~2 Zhi-Xin LIN~3 Qing-Kang WANG~1* Yi-Xue LI~4 1 Institute of Micro/Nano Science and Technology,shanghai Jiaotong University,shanghai 200030,china 2.shanghai center for bioinformation Technology,shanghai 2.02.5,china 3 College of Life Science and Technology,shanghai Jiaotong University,shanghai 200030,china 4 bioinformation center of shanghai Institutes for Biological Sciences,Chinese Academy of Sciences,shanghai 200031,china shanghai center for bioinformation Technology Shanghai 200235China Institute of Micro/Nano Science and Technology Shanghai Jiaotong UniversityShanghai 200030China

Efficient massive mapping algorithm (EMMA),an algorithm on efficiently mapping massivecDNAs onto genomic sequences,has recently been *** process of mapping massive cDNAsonto genomic sequences has been improved using more approximate mapping filtering based on an enhancedsuffix array coupled with a pruned fast hash table,algorithms of block alignment extensions,and *** compared with the classical BLAT software in this field,the computing of EMMA ranges fromtwo to forty-one times faster under similar prediction precisions.

关键词： cDNA mapping maximal exact match enhanced suffix array pruned fast hash table extension algorithm

Conformational flexibility of β-secretase: molecular dynamics simulation and essential dynamics 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

Acta Pharmacologica Sinica 2004年第6期25卷 3-11页

作者： Bing XIONG, Xiao-qin HUANG, Ling-ling SHEN, Jian-hua SHEN 2,Xiao-min LUO, Xu SHEN, Hua-liang JIANG2, Kai-xian CHENDrug Discovery and Design center, State Key Laboratory of Drug research, shanghai Institute of Materia Medica,shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, shanghai 201203, china Drug Discovery and Design center State Key Laboratory of Drug Research Shanghai Institute of Materia Medica Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Shanghai 201203 China

AIM: Based on the structural analysis to reveal the mechanism of ligand binding to b-secretase and the specificityof each binding sub-site. METHODS: Molecular dynamics was used to simulate on the ligand free b-secretase andligand bound b-secretase. The trajectories were analyzed using the essential dynamics, and the significant confor-mational change was illustrated employing the DynDom program. RESULTS: The essential dynamics and DynDomanalyses clearly showed that the b-secretase experienced a large conformational change upon the substrate orinhibitor binding. The flap structure adopted a swing motion, gradually covering the active site to facilitate theligand binding process. Residues Ser86 and Ile87 served as the hinge point. Inhibitor-enzyme interaction analysisrevealed that residues at P2, P1, and P1 positions of the inhibitor were very important for the binding, and residuesat P2 and P3 positions may be modified to improve the binding specificity. S3 subsite of the enzyme still hadspace to modify the inhibitors in increasing the binding affinity. CONCLUSION: The information presented hereis valuable and could be used to identify small molecular inhibitors of b-secretase.

关键词： molecular dynamics secretase essential dynamics computer simulation Alzheimer disease

EFFECT OF PAN-MILLING STRESS ON CRYSTAL STRUCTURES OF HIGH DENSITY POLYETHYLENE

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 Journal of Polymer Science 2000年第4期18卷 363-367页

作者： Hua Huang Polymer research Institute, Sichuan University, Chengdu 610065, china School of chemistry and Chemical Technology,shanghai Jiao Tong University ,shanghai 200240,china Sichuan Univ Polymer Res Inst Chengdu 610065 Peoples R China shanghai Jiao Tong Univ Sch Chem & Chem Technol Shanghai 200240 Peoples R China

A detailed study was performed on the crystal structures of pan-milled high-density polyethylene (HDPE) using differential scanning calorimetry (DSC) and X-ray diffraction. The crystallinity of HDPE first decreased slightly, followed by a gradual increase with increasing milling times. Monoclinic crystals appeared after 4 cycles of milling. With increasing times of milling, the proportion of monoclinic crystals increased significantly while the proportion of orthorhombic crystals decreased gradually. With increasing times of milling, the crystallite size of orthorhombic form decreased greatly, while the size of monoclinic crystallites kept almost constant during milling.

关键词： high-density polyethylene pan-milling crystal structure

Disposable amperometric biosensors based on xanthine oxidase immobilized in the Prussian blue modified screen-printed three-electrode system

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2010年第12期53卷 2581-2586页

作者： TENG YuanJie,CHEN Chen,ZHOU ChangXiang,ZHAO HongLi & LAN MinBo shanghai key Laboratory of Functional Materials Chemistry research center of Analysis Test,East china University of Science and Technology,shanghai 200237,china 1. shanghai key Laboratory of Functional Materials Chemistry research center of Analysis Test East China University of Science and Technology Shanghai 200237 China

The screen-printed three-electrode system was applied to fabricate a new type of disposable amperometric xanthine oxidase ***-working,carbon-counter and Ag/AgCl reference electrodes were all manually printed on the polyethylene terephthalate substrate forming the screen-printed three-electrode system by the conventional screen-printing *** a mediator,Prussian blue could not only catalyze the electrochemical reduction of hydrogen peroxide produced from the enzyme reaction,but also keep the favorable potential around 0 *** optimum operational conditions,including pH,potential and temperature,were *** sensitivities of xanthine and hypoxanthine detections were 13.83 mA/M and 25.56 mA/M,respectively.A linear relationship was obtained in the concentration range between 0.10μM and 4.98μM for xanthine and between 0.50μM and 3.98μM for *** small Michaelis-menten constant value of the xanthine oxidase biosensor was calculated to be 3.90 μ*** results indicate that the fabricated xanthine oxidase biosensor is effective and sensitive for the detection of xanthine and hypoxanthine.

关键词： xanthine oxidase xanthine hypoxanthine screen-printed three-electrode system Prussian blue

Experimental EOS determination of aluminum at Mbar pressure

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2004年第4期47卷 416-423页

作者： CHEN Jianping1,2, LI Ruxin1, ZENG Zhinan1, WANG Xingtao1 & XU Zhizhan1 1. shanghai Institute of Optics and Fine Mechanics, shanghai 201800, china 2. Beijing Aeronautical Technology research center, Beijing 100076, china 1. shanghai Institute of Optics and Fine Mechanics 201800 Shanghai China 2. Beijing Aeronautical Technology research center 100076 Beijing China

A shock wave is driven by a laser pulse of 1.2 ps duration (FWHM), with the intensity of ～1014 W/cm2 at 785 nm, irradiating a 500 nm thick aluminum foil. A chirped laser pulse split from the main pulse is used to detect the shock breakout process at the rear surface of the target based on frequency domain interferometry. The mean shock velocity determination benefits from the precise synchronization (＜100fs resolution) of the shock pump and probe laser pulses, which is calculated from the time the shock takes to travel the 500 nm thick aluminum. The released particle velocity determination benefits from the chirped pulse frequency domain interferometry. The average shock velocity is 15.15 km/s and the shock release particle velocity is 15.24 km/s, and the corresponding pressure after shock is 3.12 Mbar under our experimental condition.

关键词： shock wave, equation of state, chirped laser pulse.