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
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
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
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
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
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
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
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
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
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
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
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
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
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
基金Project BK2008128 supported by the Natural Science Foundation of Jiangsu Province
文摘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.
基金supported by URT program of Beijing Institute of Petrochemical Technology(2015J00058 and 2015J00056)
文摘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.
文摘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.
文摘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.
基金This work was supported by the National Natural Science Foundation of China (No. 29425005).
文摘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.
基金The National High Technology Research and Development Program of China(863 Program)(No.2006AA04Z416)the National Science Fund for Distinguished Young Scholars(No.50725828)
文摘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.
基金Supported by the National Natural Science Foundation of China (No.20436040) and Xi'an Municipal Project for Industrial Research (No. GG06015).
文摘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.
基金financially supported by the Major Basic Research Project of the Ministry of Science and Technology of China(Grant No.2014CB448000)the National Natural Science Foundation of China(Grant Nos.41772207,41422206)。
文摘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.
基金Financial supports for this work provided by the National Basic Research Program of China(2013CB227900)the Innovation of Graduate Student Training Project in Jiangsu Province of China(CXZZ13_0934)
文摘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.
基金Supported by the China Science and Technology Major Project(2017ZX05030-002)China National Petroleum Corporation Scientific Research and Technology Development Project(2019D-4309)
文摘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.
文摘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.
基金This research was funded by the National Natural Science Foundation of China(NSFC,Project No.51775308)National Natural Science Foundation of Hubei(No.2021CFB236)+1 种基金Youth Talent Project of Hubei Provincial Department of Education(No.Q20201205)Hubei Key Laboratory of Hydroelectric Machinery Design&Maintenance Open Foundation(No.2020KJX04).The authors would like to thank for these financial supports.
文摘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.
基金Sponsored by the National Natural Science Foundation of China (60374069) and the Excellent Young Scholars Research Fund of Beijing Institute of Technology (000Y01-3).
文摘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.
基金This research was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB 0470000)the National Natural Science Foundation of China(22032006,22072169 and 22102201)+3 种基金the National Key Research and Development Program of China(2021YFA0716304)the Key Research Project of Shandong Provincial Natural Science Foundation(ZR2021ZD27)the Gansu Province Basic Research Innovation Group Project(22JR5RA093)the Special Research Assistant Project of the Chinese Academy of Sciences。
文摘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.