期刊文献+
共找到19篇文章
< 1 >
每页显示 20 50 100
URBAN REGIONAL STRUCTURES TRANSFORMATION AND SUSTAINABLE DEVELOPMENT: CASE STUDY OF NANJING MEGALOPOLIS 被引量:1
1
作者 XU Yi-lun WU Qi-yan REN Dong-ming 《Chinese Geographical Science》 SCIE CSCD 2000年第4期32-38,共7页
s: Since 1978, many changes have happened on the background of urban regional structure in China, such as the economy system restructuring, the social transforming including the population flow accelerating and social... s: Since 1978, many changes have happened on the background of urban regional structure in China, such as the economy system restructuring, the social transforming including the population flow accelerating and social demand diversifying and individualizing, the political and economic systems reforms, the rise of the real estate market and the changing relationship between human and nature. From the macroscopic view, these changes make the national urban system to be a newer pattern with a widening gap among the cities in spite of the rising of the cities as a whole. At the same, the urban land use structures are changing with both the trends of intensification and diversification, and the trends of the regional diversification and the economic integration. Besides, urban structures with multiple centers are emerging in several metropolitan areas in China. These changes and trends mentioned above are confirmed by a case study of Nanjing City, a growing metropolitan area in east China. The case study also points out some problems in urban regional structure reforming, especially the poor social and ecological considerations. We should pay more attention to some ideas like balance of intensification and decentralization, development of suburban centers and a reasonable mixing of the functional activities to develop a sustainable urban regional structure. 展开更多
关键词 urban regional structure Nanjing megalopolis sustainable development
下载PDF
Time analysis of regional structure of large-scale particle using an interactive visual system
2
作者 Yihan Zhang Guan Li Guihua Shan 《Visual Informatics》 EI 2022年第2期14-24,共11页
N-body numerical simulation is an important tool in astronomy.Scientists used this method to simulate the formation of structure of the universe,which is key to understanding how the universe formed.As research on thi... N-body numerical simulation is an important tool in astronomy.Scientists used this method to simulate the formation of structure of the universe,which is key to understanding how the universe formed.As research on this subject further develops,astronomers require a more precise method that enables expansion of the simulation and an increase in the number of simulation particles.However,retaining all temporal information is infeasible due to a lack of computer storage.In the circumstances,astronomers reserve temporal data at intervals,merging rough and baffling animations of universal evolution.In this study,we propose a deep-learning-assisted interpolation application to analyze the structure formation of the universe.First,we evaluate the feasibility of applying interpolation to generate an animation of the universal evolution through an experiment.Then,we demonstrate the superiority of deep convolutional neural network(DCNN)method by comparing its quality and performance with the actual results together with the results generated by other popular interpolation algorithms.In addition,we present PRSVis,an interactive visual analytics system that supports global volume rendering,local area magnification,and temporal animation generation.PRSVis allows users to visualize a global volume rendering,interactively select one cubic region from the rendering and intelligently produce a time-series animation of the high-resolution region using the deep-learning-assisted method.In summary,we propose an interactive visual system,integrated with the DCNN interpolation method that is validated through experiments,to help scientists easily understand the evolution of the particle region structure. 展开更多
关键词 Visual analytics Frame interpolation INTERACTIVE Particle region structure
原文传递
Structure and Kinematics of Emission Line Regions in AGN
3
作者 Wolfram Kollatschny 《天文研究与技术》 CSCD 北大核心 2003年第S1期32-41,共10页
I will review some key aspects of the physical conditions of the line emitting regions in AGN. The innermost BLR extends at radii of light days to light weeks from the central ionizing source. There are strong indicat... I will review some key aspects of the physical conditions of the line emitting regions in AGN. The innermost BLR extends at radii of light days to light weeks from the central ionizing source. There are strong indications that the BLR clouds are connected to the outer region of an accretion disk. Trends of radial acceleration of the line emitting clouds have been found in the extended narrow line region. Ⅰ will concentrate on observations taken in the optical wavelength range. Finally, Ⅰ will discuss different methods to determine the mass of the central supermassive black hole from the emission lines. 展开更多
关键词 structure and Kinematics of Emission Line Regions in AGN 110 FIGURE
下载PDF
Study on fine structure of crust-mantle transi-tion zone in Yanqing-Hailai basin based on CDP and DSS data
4
作者 成瑾 李清河 《Acta Seismologica Sinica(English Edition)》 CSCD 1998年第1期78-85,共8页
The fine structure of crust mantle transition zone in Yanqing Hailai(Yan Huai basin) basin has been analyzed and discussed by using the data of Yanqing Hailai deep seismic reflection profile and Beijing Huailai ... The fine structure of crust mantle transition zone in Yanqing Hailai(Yan Huai basin) basin has been analyzed and discussed by using the data of Yanqing Hailai deep seismic reflection profile and Beijing Huailai Fengzhen deep seismic sounding profile obtained respectively in 1992 and in 1993. The primary model is established based on CDP stacking profile. The phases of seismic refraction waves and wide angle reflection waves are analyzed, travel time inversion is carried out and 2 D ray tracing is computed. Synthetic seismograms are completed by using re flectivity method for waveform fitting of phases P M and P M′, they are reflection waves from both the upper and the lower boundaries of the crust mantle transition zone in this basin. The results show that the P M′ reflection waves are stronger at some points and come from the lower boundary of Moho discontinuity. It is confirmed and inter preted that the Moho discontinuity in Yanqing Hailai basin consists of a group of thin layers with alternatively higher and lower velocities. 展开更多
关键词 seismic reflection and refraction Yanqing Hailai basin fine structure crust mantle transition region travel time inversion
下载PDF
A research on the geothermal structure in Yanqing-Huailai Basin and its neighbouring region
5
作者 祖金华 吴乾蕃 廉雨方 《Acta Seismologica Sinica(English Edition)》 CSCD 1997年第4期115-118,共4页
AresearchonthegeothermalstructureinYanqing┐HuailaiBasinanditsneighbouringregionJIN-HUAZU(祖金华)QIAN-FANWU(吴乾蕃)... AresearchonthegeothermalstructureinYanqing┐HuailaiBasinanditsneighbouringregionJIN-HUAZU(祖金华)QIAN-FANWU(吴乾蕃)YU-FANGLIAN(廉雨方)... 展开更多
关键词 terrestrial heat flow two dimensional temperature structure Yanqing Huailai Basin and its neighbouring regions
下载PDF
Advances in Research on Urban Green Spaces from the Perspective of Urban Geography
6
作者 PENG Danlu 《Journal of Landscape Research》 2021年第1期58-63,共6页
The construction of urban green space has attracted extensive attention of researchers under the background of urban sustainable development and ecological civilization construction.The research of urban green space i... The construction of urban green space has attracted extensive attention of researchers under the background of urban sustainable development and ecological civilization construction.The research of urban green space involves ecology,geography,economics,sociology and other disciplines,among which geography has played an important role in promoting the study and practice of green space in terms of research perspectives,methods and techniques,planning and management.In this paper,the important role of urban geography in green space research is analyzed from defi nition,classifi cation to multidisciplinary background,and the research and practice progress of green space in urban geography are summarized in four aspects:characteristics and division of green space,relationship between green space and urban regional structure,service function of urban green space,and the relationship between green space and urban development.Finally,the practical achievements of green space research are illustrated from the perspective of urban geography. 展开更多
关键词 Urban geography Green space CHARACTERISTICS regional structure Service function
下载PDF
Features of isostatic gravity anomaly and seismic activity in the Central Asian region
7
作者 方盛明 冯锐 +3 位作者 田长征 孙桂香 王志理 李长法 《Acta Seismologica Sinica(English Edition)》 CSCD 1997年第6期105-109,共5页
In this paper, the lithospheric isostatic gravity anomaly with its distribution features in the Central Asian region (30°~70°N, 50°~140°E), according to the research of the lithospheric isostati... In this paper, the lithospheric isostatic gravity anomaly with its distribution features in the Central Asian region (30°~70°N, 50°~140°E), according to the research of the lithospheric isostatic principle, is discussed. Moreover, some primary structures and seismic activities in this region are discussed. 展开更多
关键词 isostatic gravity anomaly regional structure seismic activity the Central Asian region
下载PDF
Experimental Observation of the Ore-Forming Fluid NaCl-H_2O System in the Earth Interior 被引量:5
8
作者 ZHANG Ronghua and HU Shumin Open Research Laboratory of Geochemical Kinetics, Chinese Academy of Geological Sciences,26 Baiwanzhuang Road, Beijing 100037, China 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 1999年第1期47-64,共18页
The NaCl-H_2O binary system is a major component of solutions coexisting with ores. Observation ofsaturated solutions of NaCl-H_2O by using the method of hydrothermal diamond anvil cell (HDAC) is a new approach tothe ... The NaCl-H_2O binary system is a major component of solutions coexisting with ores. Observation ofsaturated solutions of NaCl-H_2O by using the method of hydrothermal diamond anvil cell (HDAC) is a new approach tothe study of ore-forming fluids. The salinities of NaCl-H_2O solutions in experimental observation are in a range of 32-55%. The observed temperature range is 25℃-850℃, and the pressure range 1 atm-10 kb. In this temperature-pressure range, the supercritical single phase, two phases (L,V) close to the critical state and two-phased (L+V) immis-cible region were observed. And for the salinity of 35% the two phase L+V immiscible region of NaCl-H_2O solutionwas observed in a range of 253-720℃. Another temperature range, 400-817℃, was observed for the immiscible two-phased region of 50% salinity solution. In the high-temperature part of the two-phased immiscible region, the phase na-ture is very unstable. A "critical phenomenon" was observed when the heating path was very close to the critical state.It is possible to observe a 'critical phenomenon': an "explosion" occurred almost constantly at the interface between theliquid and vapour and the interface is rather obscure. A continuous transition between phases L and V could be foundin the immiscible L+V phase while heating continuously. Moreover, as the NaCl-H_2O solution was separated into liq-uid and vapour phases, static charges surrounding each vapour bubble could be seen, and these bubbles were attractedtogether by the static charges to form a special solution structure. Besides, critical states of different salinities of NaCl-H_2O were observed in order to study the properties of the fluids occurring in the rocks in the earth interior, the origin ofore-bearing fluids and the significance of supercritical fluid with respect to the ore formation. The comparison of the sa-linity data of the fluid inclusions in the minerals of ore deposits with observations of NaCl-H_2O under HDAC in theconditions of high temperatures and pressures, combined with further thermodynamic analysis of ore-formation condi-tions would explain in depth the factors determining the ore formation. 展开更多
关键词 critical phenomenon solution structure of the two-phased immiscible region ore-forming hydrothermal solutions
下载PDF
Identification and characterization of adult alpha-and beta-globin genes and their genomic arrangement in Pseudosciaena crocea 被引量:1
9
作者 CHU Wuying QIAN Ronghua +3 位作者 WANG Lianshen YU Xiameng YOU Zhenqiang YU Lian 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2006年第4期65-76,共12页
The α- and β-globin genes from Pseudosciaena crocea were cloned by rapid amplification of cDNA 3 '-end ( 3 '-RACE). The cDNA of the α-globin is 595 bp with the ATG start codon located at Position 37, the TAA st... The α- and β-globin genes from Pseudosciaena crocea were cloned by rapid amplification of cDNA 3 '-end ( 3 '-RACE). The cDNA of the α-globin is 595 bp with the ATG start codon located at Position 37, the TAA stop codon at Position 469 and the AATAAA polyadenylation signal at Position 560, which codifies 145 amino acids. The entire open reading frame of the β-globin gene is 447 bp long, which encodes 148 amino acids. Amino acid identity of the α- globin or β-globin gene compared with those reported in other fish species, ranged from 31.9% to 76.4%. When comparing with human α- and β-globins, three important alterations in the structural regions can be noted: ct39 Thr→Gln, α113 His→Tyr and β117 His→Lys. The α-globin has a unique inserted amino acid residue in the 47th position. To understand the process of globin gene duplication and identify the regulatory elements present in the intergenic and intragenic regions of globin genes, the genomic arrangement of α- and β-globin genes was investigated. The results showed that the orientation of the two genes was head-to-head relative to each other. The intergenic region between the translation initiation codons of the linked α- and β-globin genes contains classical promoter elements and the length of it is much shorter than that reported in other fish. 展开更多
关键词 Pseudosciaena crocea GLOBIN gene cloning structural region HEAD-TO-HEAD regulatory elements
下载PDF
Ecological Distribution and Significance of Metadiaptomus asiaticus Uljanirs,a Copepod Recently Found on the Qinghai-Tibetan Plateau
10
作者 WANG Hailei YUAN Xianchun ZHENG Mianping 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第S1期108-110,共3页
1 Introduction In 2006,plankton investigation was carried out in the lakes in Ali district,Tibet.7 planktonic crustaceans were identified and reported.Metadiaptomus asiaticus Uljanirs was reported for the first time o... 1 Introduction In 2006,plankton investigation was carried out in the lakes in Ali district,Tibet.7 planktonic crustaceans were identified and reported.Metadiaptomus asiaticus Uljanirs was reported for the first time on the QTP(Yuan et al.,2007).However,detailed data on this species,especially its ecological significance,were not mentioned.In this 展开更多
关键词 Metadiaptomus asiaticus Uljanirs Feature structures Ecological distribution Biogeographical region belonging
下载PDF
Prokaryotic Expression and Immunogenicity of Dominant Epitope Region of Goose Parvovirus Structural Protein VP3
11
作者 Li Shuguang Cheng Likun +4 位作者 Li Feng Zhang Na Zhao Jialei Yang Lifang Shen Zhiqiang 《Animal Husbandry and Feed Science》 CAS 2018年第1期68-71,共4页
[Objective] The paper was to develop a subunit vaccine candidate for prevention and control of goose parvovirus infection. [Method]Based on the prokaryotic expression system, the antigenic epitopes and locations of th... [Objective] The paper was to develop a subunit vaccine candidate for prevention and control of goose parvovirus infection. [Method]Based on the prokaryotic expression system, the antigenic epitopes and locations of the structural protein VP3 were predicted by software analysis,and the region displaying a large portion of antigenic epitopes was amplified by PCR. The target VP3 DNA fragment was inserted into pET-30 a-VP3 vector, was transformed into Escherichia coli BL21 competent cells for protein expression and animal test. The SPF chickens were immunized with the recombinant protein and the antisera were collected for neutralization test by using a goose embryo fibroblast. [Result] The recombinant plasmid was constructed, and the target region of VP3 protein was expressed efficiently in a soluble form. The neutralizing titers of antisera could reach up to-2.608. [Conclusion] The target region displaying a large portion of antigenic epitopes of the structural protein VP3 could be expressed efficiently in soluble form, and the expressed protein could induce neutralizing antibodies in SFP chicken. 展开更多
关键词 Goose parvovirus Structural protein VP3 Dominant epitope region Neutralization titer
下载PDF
Regional characteristics of ultrasonic structural scattering in liver
12
作者 CHEN Qimin ZHANG Xiaofei +1 位作者 LIU Binsheng YAN Bige and LIU Chunrong(Applied Acoustics Institute, Shaanxi Teachers University Xi’an, 710062)(Technical College of the Chinese People’s Armed Police Force, Xi’an, 710086) 《Chinese Journal of Acoustics》 1996年第2期97-105,共9页
In this paper, the ultrasonic spectra of liver's structural scattering wave obtained by autoregressive model and the spectral characteristics were analyzed statisticaJly The experimellt and analysis results show t... In this paper, the ultrasonic spectra of liver's structural scattering wave obtained by autoregressive model and the spectral characteristics were analyzed statisticaJly The experimellt and analysis results show that a liver can be divided into three distingulshed scattering regions. The top layer region shows approkimate Rayleigh scattering characteristic, the central region shows diffosion scattering, and the region between the top layer and centre shows random scattering. These distribution characteristics correlate with the distribution of the microstructure characteristics of liver. The experiment results provide possibilities for tissue recognition using spectrum characteristics of the regional structure scattering. 展开更多
关键词 LIVER regional structure Scattering spectrum characteristics
原文传递
A LINEAR HYBRID MODEL OF MSE AND BEM FOR FLOATING STRUCTURES IN COASTAL ZONES 被引量:2
13
作者 ZHANG Jun MIAO Guo-ping 《Journal of Hydrodynamics》 SCIE EI CSCD 2006年第6期649-658,共10页
A linear hybrid model of Mild Slope Equation (MSE) and Boundary Element Method (BEM) is developed to study the wave propagation around floating structures in coastal zones. Both the wave refraction under the influ... A linear hybrid model of Mild Slope Equation (MSE) and Boundary Element Method (BEM) is developed to study the wave propagation around floating structures in coastal zones. Both the wave refraction under the influence of topography and the wave diffraction by floating structures are considered. Hence, the model provides wave properties around the coastal floating structures of arbitrary shape but also the wave forces on and the hydrodynamic characteristics of the structures. Different approaches are compared to demonstrate the validity of the present hybrid model. Several numerical tests are carried out for the cases of pontoons under different circumstances. The results show that the influence of topography on the hydrodynamic characteristics of floating structures in coastal regions is important and must not be ignored in the most wave period range with practical interests. 展开更多
关键词 hybrid model Mild Slope Equation (MSE) Boundary Element Method (BEM) marine floating structures coastal regions wave propagation wave force
原文传递
STRUCTURE IN THE PRECORE REGION OF HEPATITIS B CORE GENE AFFECTING ITS EXPRESSION IN E.coil
14
作者 马贤凯 丁广治 +4 位作者 石成华 左平 逯好英 卢秀桂 黄翠芬 《Science China Chemistry》 SCIE EI CAS 1987年第11期1190-1198,共9页
Restriction fragments of HBV-DNA, cleaved by endonuclease HhaI,containing HBcAg gene were trimmed by BAL-31 exonuclease to remove different lengths of the precore sequence.They were inserted into plasmid pUR222 at Eco... Restriction fragments of HBV-DNA, cleaved by endonuclease HhaI,containing HBcAg gene were trimmed by BAL-31 exonuclease to remove different lengths of the precore sequence.They were inserted into plasmid pUR222 at EcoRI site through synthetic linker ligation. Transformants in E.coli BMH7118 showing different levels of HBcAg gene expression were screened and analyzed for their nucleotide sequences in the junction region both by Maxam and Gilbert’s chemical degradation method and by M13 chain termination method. Results of sequence analysis of different transformants revealed a partial palindromic (loop and stem) structure, at -7 to -35 nucleotide with regard to ATG of the HBcAg gene as position +1, which has dramatic effect on the level of expression of the inserted gene using the same promoter,SD sequence and identical N-terminus.The amount of HBcAg synthesized differed from 9% in the high expressing plasmid to less than 0.01% of the total cell proteins in the low expressing transformants.The findings 展开更多
关键词 HBeAg HBcAg structure IN THE PRECORE REGION OF HEPATITIS B CORE GENE AFFECTING ITS EXPRESSION IN E.coil
原文传递
Security Structure Transformation in the Asia-Pacific Region and the ASEAN Role
15
作者 Ren Yuanzhe 《Peace》 2016年第4期47-59,共13页
After the end of the cold war, the Asia-Pacific security structure has experienced great changes, especially on the occasion of the current "power-sharing" and "power-shifting" between China and th... After the end of the cold war, the Asia-Pacific security structure has experienced great changes, especially on the occasion of the current "power-sharing" and "power-shifting" between China and the United States in the Asia-Pacific region, the Asia-Pacific security structure adjustment is especially significant. On the one hand, the Alliance structure with the United States as the pivot has experienced transformation from a hub-spokes system to a network, has formed the hierarchical layout of new alliance, quasi-alliance and potential alliance, On the other hand, emerging economies represented by China and Russia, while reinforcing the existing coordinate security framework, reshape the Asia-Pacific and even the whole Eurasia geopolitical posture through strategic initiatives such as the Belt and Road Initiative, the Eurasian Economic Union. As the third force in the Asia-Pacific security architecture, the Association of South-East Asian Nations(ASEAN) with the construction of a series of multilateral security mechanisms provides dialogue platform for the two security architectures led by major countries, and has also become one of the feasible paths to realize the future holistic security architecture in the Asia-Pacific region. Meanwhile, the major countries strategic competitions have intensified, which has gradually eroded the ASEAN ‘s cohesion, neutrality and even the central position in a holistic security architecture. The future's reconstruction of the Asia-Pacific security architecture needs to find new strategic consensus and reconfirm the ASEAN central position. 展开更多
关键词 ASEAN ASIA Security structure Transformation in the Asia-Pacific Region and the ASEAN Role
原文传递
基于公路客流的中国城市网络结构与空间组织模式(英文) 被引量:13
16
作者 陈伟 刘卫东 +1 位作者 柯文前 王女英 《Journal of Geographical Sciences》 SCIE CSCD 2018年第4期477-494,共18页
The use of multi-perspective and multi-scalar city networks has gradually developed into a range of critical approaches to understand spatial interactions and linkages. In particular, road linkages represent key chara... The use of multi-perspective and multi-scalar city networks has gradually developed into a range of critical approaches to understand spatial interactions and linkages. In particular, road linkages represent key characteristics of spatial dependence and distance decay, and are of great significance in depicting spatial relationships at the regional scale. Therefore, based on highway passenger flow data between prefecture-level administrative units, this paper attempted to identify the functional structures and regional impacts of city networks in China, and to further explore the spatial organization patterns of the existing functional regions, aiming to deepen our understanding of city network structures and to provide new cognitive perspectives for ongoing research. The research results lead to four key conclusions. First, city networks that are based on highway flows exhibit strong spatial dependence and hierarchical characteristics, to a large extent spatially coupled with the distributions of major megaregions in China. These phenomena are a reflection of spatial relationships at regional scales as well as core-periphery structure. Second, 19 communities that belong to an important type of spatial configuration are identified through community detection algorithm, and we suggest they are correspondingly urban economic regions within urban China. Their spatial metaphors include the administrative region economy, spatial spillover effects of megaregions, and core-periphery structure. Third, each community possesses a specific city network system and exhibits strong spatial dependence and various spatial organization patterns. Regional patterns have emerged as the result of multi-level, dynamic, and networked characteristics. Fourth, adopting a morphology-based perspective, the regional city network systems can be basically divided into monocentric, dual-nuclei, polycentric, and low-level equilibration spatial structures, while most are developing monocentrically. 展开更多
关键词 space of flows city network urban economic region urban system monocentric structure polycentric structure community detection
原文传递
A new static induction thyristor with high forward blocking voltage and excellent switching performances 被引量:1
17
作者 张彩珍 王永顺 +1 位作者 刘春娟 汪再兴 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2010年第3期54-57,共4页
A new static induction thyristor (SITH) with a strip anode region and p- buffer layer structure (SAP-B) has been successfully designed and fabricated. This structure is composed of a p- buffer layer and lightly do... A new static induction thyristor (SITH) with a strip anode region and p- buffer layer structure (SAP-B) has been successfully designed and fabricated. This structure is composed of a p- buffer layer and lightly doped n- regions embedded in the p+-emitter. Compared with the conventional structure of a buffed-gate with a diffused source region (DSR buffed-gate), besides the simple fabrication process, the forward blocking voltage of this SITH has been increased to 1600 V from the previous value of 1000 V, the blocking gain increased from 40 to 70, and the turn-offtime decreased from 0.8 to 0.4μs. 展开更多
关键词 static induction thyristor strip anode region and p- buffer layer structure forward blocking voltage turn-off time
原文传递
Energy Absorption and Deformation Mechanism of Lotus-type Porous Coppers in Perpendicular Direction 被引量:2
18
作者 Weidong Li Kai Xu +3 位作者 Honghao Li Haoling Jia Xinhua Liu Jianxin xie 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2017年第11期1353-1361,共9页
As metallic foams used for energy absorption in the automotive and aerospace industries, recently invented lotus-type porous metals are viewed as potential energy absorbers. Yet, solid conclusion on their eligibility ... As metallic foams used for energy absorption in the automotive and aerospace industries, recently invented lotus-type porous metals are viewed as potential energy absorbers. Yet, solid conclusion on their eligibility as energy absorbers is still in question, particularly when compression is in the direction perpendicular to the axial orientation of cylindrical pores. In this work, the energy absorption of lotus-type porous coppers in the perpendicular direction is investigated at strain rates from 0.001 s^(-1) to^2400 s^(-1). The energy absorption capacity and the energy absorption efficiency are calculated to be4–16 k J/kg and 0.32–0.7, respectively, slightly inferior to metal foams and the same porous solid compressed in the parallel direction due to the shortened extent of the plateau stress region. The deformation mechanism is examined experimentally in conjunction with finite element modeling. Both suggest that gradual squeeze and collapse of pores are the mechanisms accommodating the energy absorption. The deformation is generally evenly distributed over pore ligaments and independent of strain rate. 展开更多
关键词 Lotus-type porous structure Energy absorption Plateau stress region Plastic collapse Strain rate effect
原文传递
Grouping of amino acids and recognition of protein structurally conserved regions by reduced alphabets of amino acids
19
作者 LI Jing1 & WANG Wei1,2 1 National Laboratory of Solid State Microstructure and Department of Physics, Nanjing University, Nanjing 210093, China 2 Interdisciplinary Center of Theoretical Studies, Chinese Academy of Sciences, Beijing 100080, China 《Science China(Life Sciences)》 SCIE CAS 2007年第3期392-402,共11页
Sequence alignment is a common method for finding protein structurally conserved/similar regions. However, sequence alignment is often not accurate if sequence identities between to-be-aligned se- quences are less tha... Sequence alignment is a common method for finding protein structurally conserved/similar regions. However, sequence alignment is often not accurate if sequence identities between to-be-aligned se- quences are less than 30%. This is because that for these sequences, different residues may play similar structural roles and they are incorrectly aligned during the sequence alignment using substitu- tion matrix consisting of 20 types of residues. Based on the similarity of physicochemical features, residues can be clustered into a few groups. Using such simplified alphabets, the complexity of protein sequences is reduced and at the same time the key information encoded in the sequences remains. As a result, the accuracy of sequence alignment might be improved if the residues are properly clustered. Here, by using a database of aligned protein structures (DAPS), a new clustering method based on the substitution scores is proposed for the grouping of residues, and substitution matrices of residues at different levels of simplification are constructed. The validity of the reduced alphabets is confirmed by relative entropy analysis. The reduced alphabets are applied to recognition of protein structurally conserved/similar regions by sequence alignment. The results indicate that the accuracy or efficiency of sequence alignment can be improved with the optimal reduced alphabet with N around 9. 展开更多
关键词 Grouping of amino acids and recognition of protein structurally conserved regions by reduced alphabets of amino acids
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部