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南美奥连特盆地坎潘阶碳酸盐岩建隆的识别及科迪勒拉运动早期抬升对Main-M1储集层沉积的控制作用 被引量:1
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作者 丁峰 王光付 +6 位作者 孙建芳 孙钰 李发有 薛明喜 吴洁 班舒悦 鲍志东 《古地理学报》 CAS CSCD 北大核心 2024年第1期5-16,共12页
厄瓜多尔奥连特盆地Main-M1砂岩储集层是该盆地近年来重要的构造-岩性圈闭勘探目的层系,寻找砂体和岩性尖灭带是Main-M1砂岩勘探的关键。该盆地为晚白垩世弧后热沉降盆地和新生代前陆盆地的叠合盆地,在构造上分为西部逆冲褶皱带、中部... 厄瓜多尔奥连特盆地Main-M1砂岩储集层是该盆地近年来重要的构造-岩性圈闭勘探目的层系,寻找砂体和岩性尖灭带是Main-M1砂岩勘探的关键。该盆地为晚白垩世弧后热沉降盆地和新生代前陆盆地的叠合盆地,在构造上分为西部逆冲褶皱带、中部前渊带和东部斜坡带,在前渊带发育一系列近N-S走向长轴背斜。综合观察和分析发现,在研究区内长轴背斜上生长了1个碳酸盐岩建隆,地震上具有明显的边界反射形成丘状外观和较连续的弱振幅内部反射,测井上具有厚层、近箱型低GR响应特征。该建隆表明在其沉积的坎潘阶时期,长轴背斜已经开始抬升,将背斜顶部推升至古水面附近,形成建隆局部生长的条件。压实回剥方法恢复古地貌证实,长轴背斜在坎潘阶早期开始发育,构造抬升幅度为7~10 m。由于构造抬升和建隆发育始于Main-M1沉积前,抬升古地貌可影响砂岩沉积。根据背斜上数十口已钻井Main-M1砂体厚度统计,发现背斜顶部砂岩储集层整体较发育,但古建隆顶部砂层厚度减薄或者缺失,在背斜的南部延伸段,构造顶部砂岩缺失,仅在东部侧翼富集。提出了近N-S向背斜古地貌影响Main-M1砂体沉积,使砂岩于富集于构造下倾方向的控砂模式。该模式可形成上倾尖灭型构造-岩性圈闭,从而提供了通过古地貌恢复在奥连特盆地前渊带寻找新圈闭的勘探思路。 展开更多
关键词 奥连特盆地 科迪勒拉运动 碳酸盐岩建隆 古地貌 main-M1储集层 构造-岩性圈闭
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Damage and deterioration mechanism and curing technique of concrete structure in main coal cleaning plants 被引量:10
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作者 LV Heng-lin ZHAO Cheng-ming +2 位作者 SONG Lei MA Ying XU Chun-hua 《Mining Science and Technology》 EI CAS 2009年第6期750-755,共6页
Concrete structures in main coal cleaning plants have been rebuilt and reinforced in the coal mines of the Shanghai Datun Energy Sources Co. Ltd., the first colliery of the Pingdingshan Coal Co. Ltd. and the Sanhejian... Concrete structures in main coal cleaning plants have been rebuilt and reinforced in the coal mines of the Shanghai Datun Energy Sources Co. Ltd., the first colliery of the Pingdingshan Coal Co. Ltd. and the Sanhejian mine of the Xuzhou Mining Group Co. Ltd. In these projects, the operating environment and reliability of concrete structures in the main plants of the three companies were investigated and the safety of the structures inspected. Qualitative and quantitative analyses were made on the special natural, technological and mechanical environments around the structures. On the basis of these analyses, we discuss the long-term, combined actions of the harsh natural (corrosive gases, liquids and solids) and mechanical environments on concrete structures and further investigated the damage and deteriorating mechanisms and curing techniques of concrete structures in the main coal cleaning plants. Our study can provide a theoretical basis for ensuring the reliability of concrete structures in main coal cleaning plants. 展开更多
关键词 main coal cleaning plants concrete structure operating environment reliability detection and inspection damage anddeteriorating mechanisms curing technique
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Two New Main Group Metal Coordination Polymers Based on 2,5-Furandicarboxylic Acid: Syntheses and Crystal Structures 被引量:2
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作者 王浩 刘洋 +2 位作者 陈飞 郭雨萌 章应辉 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2015年第4期585-593,共9页
By using solvothermal method, two new main group metal coordination polymers based on 2,5-furandicarboxylic acid (H2FDA) ligand, [Sr2(FDA)E(H2O)5]n (1) and [Ba4(FDA)4(H2O)10]n (2), were produced and char... By using solvothermal method, two new main group metal coordination polymers based on 2,5-furandicarboxylic acid (H2FDA) ligand, [Sr2(FDA)E(H2O)5]n (1) and [Ba4(FDA)4(H2O)10]n (2), were produced and characterized by single-crystal X-ray diffraction analyses, elemental analyses, IR, and powder X-ray diffraction. Compound 1 crystallizes in monoclinic, space group C2/c with a = 13.454(3), b = 13.426(3), c = 20.166(4) A, β = 107.06(3)°, V = 3482.4(13)A^3, Dc = 2.188 g/cm^3, CIEH14Sr2O15, Mr = 573.47, F(000) = 2256,μ(MoKα)= 6.21 mm^-1, Z = 8, R = 0.0522 and wR = 0.1229 for 2493 observed reflections (I〉 2σ(I)), and R = 0.0689 and wR = 0.1324 for all data. Compound 2 crystallizes in triclinic, space group el with α = 6.8382(14), b = 10.932(2), c = 25.571(5) A,α = 94.64(3), β= 95.41(3), γ = 107.83(3)°, V= 1799.4(6) A3, Dc = 2.484 g/cm^3, C24H28Ba4O30, Mr = 1345.82, F(000) = 1272,μ(MoKa) = 4.43 mm^-1, Z = 2, R = 0.0485 and wR = 0.0906 for 5020 observed reflections (I〉 2σ(I)), and R = 0.0706 and wR = 0.0991 for all data. In 1, the trinuclear clusters Sr3 are connected with adjacent four clusters by a carboxylate group to produce a two-dimensional (2D) sheet, which is extended by a FDA-based pillar into a 3D framework. In 2, neighbouring trinuclear clusters Ba3 are linked through two -O-C-O- of FDA^2- ligands to form one-dimensional (1D) chains, which are connected by a FDA-based pillar to construct a 2D framework. The thermal stabilities of 1 and 2 are also investigated. 展开更多
关键词 2 5-furandicarboxylic acid main group crystal structure
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Structure of the Intermetallic Compound Ni_3Al Synthesized under Compression of the Powder Mixture of Pure Elements Part Ⅰ: Phase Composition and Microstructure of Main Phase 被引量:4
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作者 M. V. Fedorischeva, V.E.Ovcharenko, O.B.Perevalova and E. V. Kozlov(Institute of Strength Physics and Materials Science, Russian Academy of Sciences, Siberian Branch, Tomsk, Russia) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1999年第6期531-535,共5页
It was shown by TEM and X-ray analysis that there are four types of grains of the main Ni3Al phase in the structure of the intermetallic obtained by the self-propagation high temperature method (SHS). Every type of gr... It was shown by TEM and X-ray analysis that there are four types of grains of the main Ni3Al phase in the structure of the intermetallic obtained by the self-propagation high temperature method (SHS). Every type of grains has its own domain and dislocation structure. There are mono- and polydomains with and without dislocations. The grains of the main phase of monoand polydomains without dislocations and polydomains with dislocations were formed by diffusion in the solid phase. In these conditions NiAl3 phase is located on the grain boundary of the main phase. The Ni2Al3 phase is located at the triple joints of the main phase. 展开更多
关键词 In Al structure of the Intermetallic Compound Ni3Al Synthesized under Compression of the Powder Mixture of Pure Elements Part Phase Composition and Microstructure of main Phase Ni
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STRUCTURE OF MAIN COMPONENT IN PERFUME "ISO-E-SUPER"
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作者 You Zhu YUAN Shu Jing PENG 《Chinese Chemical Letters》 SCIE CAS CSCD 1992年第7期507-510,共4页
Addition of myrcene and 3-methyl-3-penten-2-one followed by cyclization afforded perfume 'Iso-E-Super' with 2(?)-acetyl-2β,3β,8,8-tetramethyl-1,2,3,4,5,6,7,8-octalin as main component on the basis of its spe... Addition of myrcene and 3-methyl-3-penten-2-one followed by cyclization afforded perfume 'Iso-E-Super' with 2(?)-acetyl-2β,3β,8,8-tetramethyl-1,2,3,4,5,6,7,8-octalin as main component on the basis of its spectroscopic data. 展开更多
关键词 EU structure OF main COMPONENT IN PERFUME ISO-E-SUPER
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FORMATION OF MESOPHASE MONO-DOMAINS AND MICRO-STRUCTURES IN THIN FILMS OF A SERIES OF COPOLYETHERS CONTAINING BOTH ODD-NUMBERED METHYLENE UNITS
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作者 Feng-chao Xie Jie-ping Liu +3 位作者 Dong-hang Yan Tian-bai He Ru-qing Zheng Er-qiang Chen State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China Department of Polymer Science and Engineering College of Chemistry Peking University Beijing 100871, China 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2001年第4期391-397,共7页
The structural and morphological evolution of mono-domains in thin films has been investigated for a series of liquid crystalline (LC) copolyethers. The copolyethers studied were synthesized by the reaction of 1-(4-hy... The structural and morphological evolution of mono-domains in thin films has been investigated for a series of liquid crystalline (LC) copolyethers. The copolyethers studied were synthesized by the reaction of 1-(4-hydroxy-4 ' -biphenylyl)-2-(4-hydroxyl-phenyl)propane (TPP) with 1,7-dibromoheptane and 1,11-undecane at different compositions (coTPPs-7/11). In contrast to the solution-cast thin films without annealing, which exhibit the isotropic homogeneous molecular orientation, mono-domains with a homeotropic alignment were found in coTPP-7/11(5/5) after the thin films were annealed in the high-temperature columnar phase (Phi '). Similar to the nucleation process in polymer crystallization, transmission electron microscopic observations show that small mono-domains appear in the initial stage of annealing, where molecules form a uniaxial in-plane chain orientation. With increasing annealing time, the molecular orientation gradually became tilted with respect to the substrate surface, and finally, a uniaxial homeotropic molecular orientation was achieved after a prolonged annealing time. The lateral size of mono-domains was found to increase continuously with annealing time and grew into a circular shape, indicating an isotropic lateral growth scheme which implies a hexagonal molecular packing proved by the electron diffraction experiments. 展开更多
关键词 main-chain liquid crystalline polymer structure morphology
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Spatial structural analysis of main saddle for single tower spatial cable self-anchored suspension bridge
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作者 李建慧 李爱群 +1 位作者 袁辉辉 李喜平 《Journal of Southeast University(English Edition)》 EI CAS 2009年第3期372-375,共4页
Based on the engineering background of the Jiangxinzhou Bridge in Nanjing, issues related to the spatial main saddle of the self-anchored suspension bridge are studied. The refinement finite element model is establish... Based on the engineering background of the Jiangxinzhou Bridge in Nanjing, issues related to the spatial main saddle of the self-anchored suspension bridge are studied. The refinement finite element model is established by the secondary development technology based on the platform of the general finite element program, and a reasonable load pattern is used in its spatial structural analysis, by which its path of force transference and stress distribution are obtained. Matched with the spatial main cable, the tangency point correction method is also discussed. The results show that the lateral wall stress of the saddle groove is higher than the stress within the wall due to the role of lateral forces in the finished bridge state; the horizontal volume force of the main cable can generate a gradient distributed vertical extrusion pressure on the saddle clamping device and the main saddle body; the geometric nonlinear effect of the self- anchored suspension bridge cable system in the construction process is significant, which can be reflected in the spatial tangent point position of the main cable with the main saddle changes a lot from free cable to finished cable. 展开更多
关键词 self-anchored suspension bridge finite element main saddle spatial cable structural design
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The Design of Water-reusing Network with a Hybrid Structure Through Mathematical Programming 被引量:4
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作者 刘永忠 段海涛 冯霄 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2008年第1期1-10,共10页
A new design method for a water-reusing network, with a hybrid structure, to reduce the complexity of the network and to minimize freshwater consumption, is proposed. The unique feature of the methodology proposed .i... A new design method for a water-reusing network, with a hybrid structure, to reduce the complexity of the network and to minimize freshwater consumption, is proposed. The unique feature of the methodology proposed .in this article is to control the complexity of the water network by regulation of the control number in a water-reusing system. It combines the advantages of a conventional water-reusing network and a water-reusing net work with internal water mains. To illustrate the proposed method, a single contaminant system and a multiple contaminant system serve as examples of the problems. 展开更多
关键词 water-reusing network internal water main hybrid structure OPTIMIZATION
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Structural,Kinematic and Geochronological Study of the Main Tianshan Shear Zone in the Borohoro Ranges,NW China 被引量:1
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作者 LIU Tianlun CHEN Siyu +5 位作者 ZHANG Bo CAI Keda HAN Baofu QU Junfeng GUO Lei WANG Meng 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2021年第5期1431-1455,共25页
The western segment of the Main Tianshan shear zone(MTSZ)branches into three major dextral strike-slip shear zones in the Borohoro Ranges,northwestern China.Mylonitic rocks within these zones exhibit vertical foliatio... The western segment of the Main Tianshan shear zone(MTSZ)branches into three major dextral strike-slip shear zones in the Borohoro Ranges,northwestern China.Mylonitic rocks within these zones exhibit vertical foliations,subhorizontal lineations,and dextral kinematics.The microstructures and CPO patterns of calcite and quartz in the tectonites suggest shearing at temperatures of 200℃ to 500℃ or above.The amount of dextral displacement along the zones is less than 100 km.LA-ICP-MS U-Pb dating of zircons from some pre-kinematic granites gave ages of 364-325 Ma and 316 Ma,and zircons from a syn-kinematic leucogranite gave an age of 291 Ma.We propose that dextral shearing along the MTSZ started in the earliest Permian.Our data indicate that collision between the Yili and Junggar plates might have finished before 325 Ma or 316 Ma,with a tectonic transformation from 325 Ma to 300 Ma,resulting in intracontinental transpression from 300 Ma or 291 Ma.We suggest that the formation of the Kazakhstan orocline(KO)took place in two stages,with the early stage of bending driven by convergence related to oblique subduction,and the late stage possibly associated with lateral disarticulation as a result of the dextral strike-slip shear zones. 展开更多
关键词 structural geology geochronology dextral shearing CPO pattern Late Paleozoic main Tianshan Shear Zone Yili-North Tianshan
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Pore structure characteristics of the relative water-resisting layer on the top of the Ordovician in Longgu Coal Mine 被引量:3
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作者 Rong Huren Bai Haibo 《International Journal of Mining Science and Technology》 SCIE EI 2014年第5期657-661,共5页
In order to study the permeability and water-resisting ability of the strata on the top of the Ordovician in Longgu Coal Mine, this paper tested the permeability and porosity of the strata, investigated the fracture a... In order to study the permeability and water-resisting ability of the strata on the top of the Ordovician in Longgu Coal Mine, this paper tested the permeability and porosity of the strata, investigated the fracture and pore structure features of the strata, and identified the main channels which govern the permeability and water-resisting ability of the strata. The permeability of the upper, central and lower strata shows as 2.0504 × 10^-3-2.782762× 10^-3, 4.1092 × 10^-3 -7.3387 × 10^-3 and 2.0891 ×10^-3-3.2705 × 10-3 μm^2, respectively, and porosity of that is 0.6786-0.9197%, 0.3109-0.3951% and 0.9829-1.8655%, respectively. The results indicate that: (I) the main channels of the relative water-resisting layer are the pore throats with a diameter more than 6 μm; (2) the major proportion of pore throats in the vertical flow channel and the permeability first increases and then sharply decreases; (3) the fractures occurring from the top to 20 m in depth of the strata were filled and there occurred almost no fracture under the depth of 40 m; and (4) the ratio of turning point of the main flow channel in the strata on top of Ordovician can be used to confirm the thickness of filled water-resisting lavers. 展开更多
关键词 Relative water-resisting layer Filling effect main channels of seepage Pore structure
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Pore-throat structure characteristics and its impact on the porosity and permeability relationship of Carboniferous carbonate reservoirs in eastern edge of Pre-Caspian Basin 被引量:1
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作者 LI Weiqiang MU Longxin +8 位作者 ZHAO Lun LI Jianxin WANG Shuqin FAN Zifei SHAO Dali LI Changhai SHAN Fachao ZHAO Wenqi SUN Meng 《Petroleum Exploration and Development》 2020年第5期1027-1041,共15页
Carboniferous carbonate reservoirs at the eastern edge of the Pre-Caspian Basin have undergone complex sedimentation,diagenesis and tectonism processes,and developed various reservoir space types of pores,cavities and... Carboniferous carbonate reservoirs at the eastern edge of the Pre-Caspian Basin have undergone complex sedimentation,diagenesis and tectonism processes,and developed various reservoir space types of pores,cavities and fractures with complicated combination patterns which create intricate pore-throats structure.The complex pore-throat structure leads to the complex porosity-permeability relationship,bringing great challenges for classification and evaluation of reservoirs and efficient development.Based on the comprehensive analysis on cores,thin sections,SEM,mercury intrusion,routine core analysis and various tests,this paper systematically investigated the features and main controlling factors of pore-throats structure and its impact on the porosity-permeability relationship of the four reservoir types which were pore-cavity-fracture,pore-cavity,pore-fracture and pore,and three progresses are made.(1)A set of classification and descriptive approach for pore-throat structure of Carboniferous carbonate reservoirs applied to the eastern edge of the Pre-Caspian Basin was established.Four types of pore-throat structures were developed which were wide multimodal mode,wide bimodal mode,centralized unimodal mode and asymmetry bimodal mode,respectively.The discriminant index of pore-throat structure was proposed,realizing the quantitative characterization of pore-throat structure types.(2)The microscopic heterogeneity of pore reservoir was the strongest and four types of pore-throat structures were all developed.The pore-fracture and pore-cavity-fracture reservoirs took the second place,and the microscopic heterogeneity of pore-cavity reservoir was the weakest.It was revealed that the main controlling factor of pore-throat structure was the combination patterns of reservoir space types formed by sedimentation,diagenesis and tectonism.(3)It was revealed that the development of various pore-throat structure types was the important factor affecting poroperm relationship of reservoirs.The calculation accuracy of permeability of reservoirs can be improved remarkably by subdividing the pore-throat structure types.This study deepens the understanding of pore-throat structure of complicated carbonate reservoirs,and is conducive to classification and evaluation,establishment of precise porosity-permeability relationship and highly efficient development of carbonate reservoirs. 展开更多
关键词 Pre-Caspian Basin CARBONIFEROUS carbonate reservoir pore-throat structure main controlling factors porosity-permeability relationship
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Flexural behavior of in-plane bending glass structures for design method
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作者 吴丽丽 王元清 +2 位作者 严茂超 石永久 张恒秋 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第8期3133-3140,共8页
Experimental study was carried out on the in-plane bending behavior of glass plates without lateral supports, and the effects of the factors, such as height-to-span ratio, on the stability of glass panels were studied... Experimental study was carried out on the in-plane bending behavior of glass plates without lateral supports, and the effects of the factors, such as height-to-span ratio, on the stability of glass panels were studied. Results show that the in-plane bending glass plates with both ends simply supported and their upper edge free lose overall stability under loads, which belongs to the limit-point type of instability. It is found that the buckling load increases linearly with the increase of height-to-span ratio of the glass plates. The lateral stress of in-plane bending glass plates without lateral supports increases linearly under loads; while the large-area stress increases nonlinearly and the lateral stress is not the controlling factor of instability. In finite element analysis, the first buckling mode is regarded as the initial imperfection and imposed on the model as 1/1000 of the span of the components. The numerical buckling load according to the theory of large deflection is less than the experiment result, which is more conservative and can provide some reference for design. For the design method, when the in-plane load is imposed on the glass plate, its lateral strength and the deflection should be verified. Considering the stability of the in-plane bending glass plate without reliable lateral support, buckling is another possible failure mode and calls for verification. 展开更多
关键词 load-bearing glass structure flexural performance in-plane bending BUCKLING
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Design and Mechanical Characterization of an S-Based TPMS Hollow Isotropic Cellular Structure
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作者 Junjian Fu Pengfei Sun +3 位作者 Yixian Du Lei Tian Qihua Tian Xiangman Zhou 《Computer Modeling in Engineering & Sciences》 SCIE EI 2022年第5期695-713,共19页
Cellular structures are regarded as excellent candidates for lightweight-design,load-bearing,and energy-absorbing applications.In this paper,a novel S-based TPMS hollow isotropic cellular structure is proposed with bo... Cellular structures are regarded as excellent candidates for lightweight-design,load-bearing,and energy-absorbing applications.In this paper,a novel S-based TPMS hollow isotropic cellular structure is proposed with both superior load-bearing and energy-absorbing performances.The hollow cellular structure is designed with Boolean operation based on the Fischer-Koch(S)implicit triply periodic minimal surfaces(TPMS)with different level parameters.The anisotropy and effective elasticity properties of cellular structures are evaluated with the numerical homogenization method.The finite element method is further conducted to analyze the static mechanical performance of hollow cellular structure considering the size effect.The compression experiments are finally carried out to reveal the compression properties and energy-absorption characteristics.Numerical results of the Zener ratio proved that the S-based hollow cellular structure tends to be isotropic,even better than the sheet-based Gyroid TPMS.Compared with the solid counterpart,the S-based hollow cellular structure has a higher elastic modulus,better load-bearing and energy absorption characteristics. 展开更多
关键词 Hollow cellular structure triply periodic minimal surfaces isotropic property energy absorption load-bearing
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Modeling of 3D-structure for regular fragments of low similarity unknown structure proteins
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作者 彭志红 Chen Jie Lin Xiwen Sang Yanchao 《High Technology Letters》 EI CAS 2007年第4期431-435,共5页
Because it is hard to search similar structure for low similarity unknown structure proteins directly from the Protein Data Bank (PDB) database, 3D-structure is modeled in this paper for secondary structure regular ... Because it is hard to search similar structure for low similarity unknown structure proteins directly from the Protein Data Bank (PDB) database, 3D-structure is modeled in this paper for secondary structure regular fragments (α-Helices, β-Strands) of such proteins by the protein secondary structure prediction software, the Basic Local Alignment Search Tool (BLAST) and the side chain construction software SCWRL3. First, the protein secondary structure prediction software is adopted to extract secondary structure fragments from the unknown structure proteins. Then, regular fragments are regulated by BLAST based on comparative modeling, providing main chain configurations. Finally, SCWRL3 is applied to assemble side chains for regular fragments, so that 3D-structure of regular fragments of low similarity unknown structure protein is obtained. Regular fragments of several neurotoxins are used for test. Simulation results show that the prediction errors are less than 0.06nm for regular fragments less than 10 amino acids, implying the simpleness and effectiveness of the proposed method. 展开更多
关键词 low similarity unknown structure regular segment 3D-structure modeling main chain confonnation side chain assembly
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Basic Structural Forms of Main Roof
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《岩石力学与工程学报》 EI CAS CSCD 1995年第S1期425-437,共13页
BasicStructuralFormsofMainRoofByJiangFuxing;SongZhenqiandSongYang(ShandongInstituteofCoalMiningandTechnology... BasicStructuralFormsofMainRoofByJiangFuxing;SongZhenqiandSongYang(ShandongInstituteofCoalMiningandTechnology,Taian271019)SUMM... 展开更多
关键词 Basic structural Forms of main Roof
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Ultra-low Friction and High Load-Bearing Hydrogel with Tubular Structure Based on Controllable Light-Induced Dissociation
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作者 Song Yang Jianqing Yu +7 位作者 Zhizhi Zhang Hao Yang Yaling Wan Bo Yu Shuanhong Ma Yanfei Ma Feng Zhou Weimin Liu 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2023年第20期2679-2683,共5页
With high water content,excellent biocompatibility and lubricating properties,and a microstructure similar to that of the extracellular matrix,hydrogel is becoming one of the most promising materials as a substitute f... With high water content,excellent biocompatibility and lubricating properties,and a microstructure similar to that of the extracellular matrix,hydrogel is becoming one of the most promising materials as a substitute for articular cartilage.However,it is a challenge for hydrogel materials to simultaneously satisfy high loading and low friction.Most hydrogels are brittle,with fracture energies of around 10 J·m^(-2),as compared with∼1000 J·m^(-2) for cartilage.A great deal of effort has been devoted to the synthesis of hydrogels with improved mechanical properties,such as increasing the compactness of the polymer network,introducing dynamic non-covalent bonds,and increasing the hydrophobicity of the polymer,all at the expense of the lubricating properties of the hydrogel.Herein,we develop a hydrogel material with anisotropic tubular structures where the compactness gradually decreases and eventually disappears from the surface to the subsurface,achieving a balance between lubrication and load-bearing.The porous layer with hydrophilic carboxyl groups on the surface exhibits extremely low friction(coefficient of friction(COF)∼0.003,1 N;COF∼0.08,20 N)against the hard steel ball,while the bottom layer acts as an excellent load-bearing function.What is more,the gradual transition of the tubular structures between the surface and the subsurface ensures the uniform distribution of friction stress between a lubricating and bearing layers,which endows the material with long-lasting and smooth friction properties.The extraordinary lubricious performance of the hydrogels with anisotropic tubular structure has potential applications in tissue engineering and medical devices. 展开更多
关键词 Ultra-low friction HYDROGELS Anisotropic Hydroge structure High load-bearing Biomimetic synthesis Microstructures
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美国“去风险”对中国产业链供应链安全的影响及应对 被引量:8
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作者 蔡宏波 郑涵茜 余天赐 《财经问题研究》 北大核心 2024年第1期33-43,共11页
在大国竞争加剧、突发公共卫生事件冲击和乌克兰危机持续等多重不确定性因素叠加的背景下,全球产业链供应链正进入重要的重塑阶段。与此同时,美国先后提出对华“脱钩”“去风险”,以减少其对中国产业链供应链的依赖,这严重影响了全球产... 在大国竞争加剧、突发公共卫生事件冲击和乌克兰危机持续等多重不确定性因素叠加的背景下,全球产业链供应链正进入重要的重塑阶段。与此同时,美国先后提出对华“脱钩”“去风险”,以减少其对中国产业链供应链的依赖,这严重影响了全球产业链供应链的稳定畅通。首先,本文界定产业链供应链安全范畴主要包括主体要素安全和结构要素安全。其次,辨析美国“脱钩”“去风险”政策意图的异同,并就现阶段美国“去风险”对中国产业链供应链安全的主要影响和中国所面临的现实挑战进行论述。分析发现,美国“去风险”对中国产业链供应链安全的主要影响包括:一是美国通过控制核心技术、中间品出口和关键资源危及中国产业链供应链主体要素安全。二是通过制造业回流、“近岸外包”“友岸外包”重塑全球产业空间布局,威胁中国产业链供应链结构要素安全。三是通过友好国家网络拉拢盟友,增加中国产业链供应链被排除风险。最后,本文据此提出中国如何在美国“去风险”背景下维护产业链供应链安全稳定的政策建议。 展开更多
关键词 产业链供应链安全 主体要素安全 结构要素安全 近岸外包 友岸外包
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弹−塑性基础边界两侧采空(留煤柱)基本顶板结构初次破断特征
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作者 陈冬冬 李子健 +5 位作者 谢生荣 何富连 罗昱 蒋再胜 马翔 李辉 《煤炭学报》 EI CAS CSCD 北大核心 2024年第5期2195-2211,共17页
为了研究两侧采空留煤柱工程条件下基本顶板结构的断裂位态及工程指导意义,构建考虑实体煤弹塑性变形与两侧煤柱宽度及支撑能力弱化的基本顶板结构双塑化基础边界力学模型,基于有限差分算法与主弯矩破断准则系统计算了在非对称煤柱区和... 为了研究两侧采空留煤柱工程条件下基本顶板结构的断裂位态及工程指导意义,构建考虑实体煤弹塑性变形与两侧煤柱宽度及支撑能力弱化的基本顶板结构双塑化基础边界力学模型,基于有限差分算法与主弯矩破断准则系统计算了在非对称煤柱区和长边实体煤区的断裂线形态、区位属性及整体位态特征,并从7个层面、横纵向4对区域与传统模型对比,阐明新模型所得新结论及工程意义。结论如下:(1)两侧非对称煤柱参数对长边实体煤区域的基本顶主弯矩及破断位置影响小,但分别显著影响煤柱区的主弯矩大小、位置及断裂形态。两侧煤柱区(较强/宽煤柱区+较弱/窄煤柱区)基本顶断裂线形态有3类演化模式,随基本顶厚度及弹模增大而煤柱宽度、支撑能力及悬顶跨度减小,其变化规律为:非对称的“连续单弧形+连续单弧形”→“连续单弧形+开口间断双短弧形”→非对称的“开口间断双短弧形+开口间断双短弧形”。(2)长边实体煤区基本顶的断裂线主要有3类区位属性,随基本顶厚度及弹模增大而实体煤的塑性区宽度、塑化程度及悬顶跨度减小,其演变规律为:断裂线在塑性煤体区(C-S式)→弹塑性煤体分界区(C-TS式)→弹性煤体区(C-T式);(3)考虑断裂线区位属性,随基本顶厚度和弹模增大而煤柱宽度、支撑能力及悬顶跨度减小的基本顶全区域破断模式及演变规律为:C-S式的■→C-TS式的■→C-T式的■→C-T式的■→C-T式的■。针对研究两侧采空(煤柱)基本顶板结构破断的3类力学模型,从7个层面对比了3类模型的重要区别,从横向4个区域(开采区域的前方与后方、两侧煤柱区)与纵向4个区域(非对称遗留煤柱下伏、下伏开采空间出/进煤柱/体)阐明了其重要工程作用。 展开更多
关键词 遗留煤柱 基本顶 两侧采空 弹−塑性基础 板结构
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一种自升式风电安装船的主船体结构总强度设计
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作者 孙雪荣 张勇 +1 位作者 沈玉琦 邵武豪 《舰船科学技术》 北大核心 2024年第14期57-62,共6页
本文借助三维有限元直接计算设计技术,结合依托自升自航式一体化海上风电安装平台自身特有的结构布置、任务使命,从船体梁剖面特性、船体梁剖面载荷出发,详细阐述四桩腿式风电安装平台的开孔群式主船体结构总强度设计流程和方法,为海上... 本文借助三维有限元直接计算设计技术,结合依托自升自航式一体化海上风电安装平台自身特有的结构布置、任务使命,从船体梁剖面特性、船体梁剖面载荷出发,详细阐述四桩腿式风电安装平台的开孔群式主船体结构总强度设计流程和方法,为海上风电安装平台的大型化、平台主体结构的规范化和轻量化设计研发提供基础。 展开更多
关键词 风电安装平台 总纵强度 开孔群式 主船体结构
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北京2022年冬奥会内场主火炬抗风性能研究
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作者 李波 胡涛 +5 位作者 田玉基 刘悦 卢啸 张范 宋晓峰 白凡 《工程力学》 EI CSCD 北大核心 2024年第10期43-48,共6页
北京2022年冬奥会和冬残奥会主火炬,是典型的舞美造型结构体,呈大面积薄壁状,对风荷载极为敏感,在点火仪式中有倾斜支撑和竖直悬挂两种典型状态。其中,倾斜支撑状态需要确定结构设计所需的风荷载,竖直悬挂状态需要给出主火炬的风振响应... 北京2022年冬奥会和冬残奥会主火炬,是典型的舞美造型结构体,呈大面积薄壁状,对风荷载极为敏感,在点火仪式中有倾斜支撑和竖直悬挂两种典型状态。其中,倾斜支撑状态需要确定结构设计所需的风荷载,竖直悬挂状态需要给出主火炬的风振响应。该文基于实测数据,给出了国家体育场周边的平均风速剖面和湍流度剖面,通过缩尺模型风环境风洞试验及2月份局地风速概率分布,确定了主火炬结构倾斜支撑状态与竖直悬挂状态的正常运行风速;通过主火炬倾斜支撑和竖直悬挂状态的测力风洞试验,得到了作用于主火炬风荷载的体型系数;并通过随机振动分析给出了竖直悬挂状态的风振响应,为北京2022年冬奥会主火炬点火仪式的顺利进行提供了技术支撑。 展开更多
关键词 冬奥会 主火炬结构 点火仪式 风荷载 风洞试验 风振
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