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Metal-organic framework-based CO

Yujie Ban, Meng Zhao, Weishen Yang

《化学科学与工程前沿（英文）》 2020年 第14卷 第2期   页码 188-215 doi: 10.1007/s11705-019-1872-6

摘要： A low-carbon economy calls for CO capture technologies. Membrane separations represent an energy-efficient and environment-friendly process compared with distillations and solvent absorptions. Metal-organic frameworks (MOFs), as a novel type of porous materials, are being generated at a rapid and growing pace, which provide more opportunities for high-efficiency CO capture. In this review, we illustrate a conceptional framework from material design and membrane separation application for CO capture, and emphasize two importance themes, namely (i) design and modification of CO -philic MOF materials that targets secondary building units, pore structure, topology and hybridization and (ii) construction of crack-free membranes through chemical epitaxy growth of active building blocks, interfacial assembly, ultrathin two-dimensional nanosheet assembly and mixed-matrix integration strategies, which would give rise to the most promising membrane performances for CO capture, and be expected to overcome the bottleneck of permeability-selectivity limitations.

关键词： CO2 capture     CO2-philic MOFs     crack-free membranes    

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Full-band error control and crack-free surface fabrication techniques for ultra-precision fly cutting

F. H. ZHANG, S. F. WANG, C. H. AN, J. WANG, Q. XU

《机械工程前沿（英文）》 2017年 第12卷 第2期   页码 193-202 doi: 10.1007/s11465-017-0448-8

摘要：

Large-aperture potassium dihydrogen phosphate (KDP) crystals are widely used in the laser path of inertial confinement fusion (ICF) systems. The most common method of manufacturing half-meter KDP crystals is ultra-precision fly cutting. When processing KDP crystals by ultra-precision fly cutting, the dynamic characteristics of the fly cutting machine and fluctuations in the fly cutting environment are translated into surface errors at different spatial frequency bands. These machining errors should be suppressed effectively to guarantee that KDP crystals meet the full-band machining accuracy specified in the evaluation index. In this study, the anisotropic machinability of KDP crystals and the causes of typical surface errors in ultra-precision fly cutting of the material are investigated. The structures of the fly cutting machine and existing processing parameters are optimized to improve the machined surface quality. The findings are theoretically and practically important in the development of high-energy laser systems in China.

关键词： ultra-precision fly cutting     large-aperture KDP crystals     spatial frequency     processing error    

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Feasibility of crack free reinforced concrete bridge deck from materials composition perspective: a state

Mahdi AREZOUMANDI

《结构与土木工程前沿（英文）》 2015年 第9卷 第1期   页码 91-103 doi: 10.1007/s11709-015-0274-1

摘要： Early age cracking on bridge deck has been the subject of many studies for years. Cracking is a major concern because it leads to premature deterioration of structures. Millions of dollars spent to repair the cracked bridge decks each year. To design an appropriate mixture for crack free bridge deck, it is important to study previous researches. This paper presents a comprehensive literature review of the performance of different materials compositions as well as methods have been used to reduce and control bridge deck cracks. Different material compositions and methods are discussed in terms of their performances as well as advantages and disadvantages.

关键词： bridge deck     crack     fiber     shrinkage     shrinkage reducing admixture    

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A hypothesis for crack free interior surfaces of Longyou caverns caved in argillaceous siltstone 2000

Zhong Qi YUE, Shaopeng FAN, Zhifa YANG, Lihui LI, Luqing ZHANG, Zhongjian ZHANG,

《结构与土木工程前沿（英文）》 2010年 第4卷 第2期   页码 165-177 doi: 10.1007/s11709-010-0018-1

摘要： Five complete caverns were discovered in Longyou in 1992. They were manually caved in argillaceous siltstone at shallow depths more than 2000 years ago. When they were un-watered, their integrity was maintained completely, and their interior rock surfaces were free of old cracks. Since then, however, the rock’s interior faces have initiated and propagated more and more cracks. This paper attempts to address the question of why the rock interior faces were free of old cracks once they were unearthed. To address this question, this paper proposes a hypothesis that the argillaceous siltstone has the ability of self-healing its cracks over a short period of time under weak acid water environment. Data and evidence are presented herewith to prove the hypothesis. They include observations and measurements in the field and test results in the laboratory. Specifically, a three-point bending test is used to form a tensile crack in a rectangular rock specimen and a dead load test for the specimen immersed in initially weak acid water is used for self-healing its crack. The results have shown that the argillaceous siltstone is in a state of weak alkalinity and the rain water at the site is in a state of weak acidity. Therefore, when it is immersed in weak acid water for some time, the argillaceous siltstone would be able to make chemical reactions to generate new minerals such as calcite. The new minerals would be able to infill the cracks and then heal the crack within a few years. Once the crack is self-healed, the rock can regain its strength and integrity. Consequently, the rock interior surfaces could be free of old cracks when the water was pumped out of the caverns.

关键词： rock cavern     grotto     Longyou     argillaceous siltstone     crack     water     environment     self-healing    

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Recovery of free volume in PIM-1 membranes through alcohol vapor treatment

Faiz Almansour, Monica Alberto, Rupesh S. Bhavsar, Xiaolei Fan, Peter M. Budd, Patricia Gorgojo

《化学科学与工程前沿（英文）》 2021年 第15卷 第4期   页码 872-881 doi: 10.1007/s11705-020-2001-2

摘要： Physical aging is currently a major obstacle for the commercialization of PIM-1 membranes for gas separation applications. A well-known approach to reversing physical aging effects of PIM-1 membranes at laboratory scale is soaking them in lower alcohols, such as methanol and ethanol. However, this procedure does not seem applicable at industrial level, and other strategies must be investigated. In this work, a regeneration method with alcohol vapors (ethanol or methanol) was developed to recover permeability of aged PIM-1 membranes, in comparison with the conventional soaking-in-liquid approach. The gas permeability and separation performance, before and post the regeneration methods, were assessed using a binary mixture of CO and CH (1:1, v:v). Our results show that an 8-hour methanol vapor treatment was sufficient to recover the original gas permeability, reaching a CO permeability>7000 barrer.

关键词： polymer of intrinsic microporosity (PIM)     PIM-1     physical aging     gas separation     vapor-phase regeneration    

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Dynamic crack propagation in plates weakened by inclined cracks: an investigation based on peridynamics

A. SHAFIEI

《结构与土木工程前沿（英文）》 2018年 第12卷 第4期   页码 527-535 doi: 10.1007/s11709-018-0450-1

摘要： Peridynamics is a theory in solid mechanics that uses integral equations instead of partial differential equations as governing equations. It can be applied to fracture problems in contrast to the approach of fracture mechanics. In this paper by using peridynamics, the crack path for inclined crack under dynamic loading were investigated. The peridynamics solution for this problem represents the main features of dynamic crack propagation such as crack bifurcation. The problem is solved for various angles and different stress values. In addition, the influence of geometry on inclined crack growth is studied. The results are compared with molecular dynamic solutions that seem to show reasonable agreement in branching position and time.

关键词： peridynamics     inclined crack     dynamic fracture     crack branching    

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Advancing ion-exchange membranes to ion-selective membranes: principles, status, and opportunities

《环境科学与工程前沿（英文）》 2023年 第17卷 第2期 doi: 10.1007/s11783-023-1625-0

摘要：

● IEM ion/ion selectivities of charge, valence, & specific ion are critically assessed.

关键词： Ion-exchange membranes     Selectivity     Separations    

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Imprinted membranes for sustainable separation processes

Laura Donato, Enrico Drioli

《化学科学与工程前沿（英文）》 2021年 第15卷 第4期   页码 775-792 doi: 10.1007/s11705-020-1991-0

摘要： The rapid industrial growth and the necessity of recovering and recycling raw materials increased the interest in the production of highly selective and efficient separation tools. In this perspective, a relevant input was given by the membrane-based technology and the production of imprinted membranes, which possess specific recognition properties at molecular and ionic level, offers the possibility of developing sustainable and green processes. Furthermore, the integration of imprinted membranes with traditional or membrane-based approaches is a promising strategy in the logic of process intensification, which means the combination of different operations in a single apparatus. This work discusses the concept and separation mechanisms of imprinted membranes. Furthermore, it presents an overview of their application in organic solvent nanofiltration, for the removal of toxic agents and recovery solvent, as well as valuable compounds. The recent advances in water treatment, such as pesticide removal and recovery of metal ions, are also discussed. Finally, potential applications of imprinted membranes in hybrid processes are highlighted, and a look into the future of membrane separations for water treatment and recovery of critical raw materials is offered.

关键词： sustainable processes     membrane separation     molecular recognition     imprinted membranes     water treatment    

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Peridynamics versus XFEM: a comparative study for quasi-static crack problems

Jinhai ZHAO, Hesheng TANG, Songtao XUE

《结构与土木工程前沿（英文）》 2018年 第12卷 第4期   页码 548-557 doi: 10.1007/s11709-017-0434-6

摘要： Peridynamics (PD) is a nonlocal continuum theory based on integro-differential equations without spatial derivatives. The fracture criterion is implicitly incorporated in the PD theory and fracture is a natural outcome of the simulation. However, capturing of complex mixed-mode crack patterns has been proven to be difficult with PD. On the other hand, the extended finite element method (XFEM) is one of the most popular methods for fracture which allows crack propagation with minimal remeshing. It requires a fracture criterion which is independent of the underlying discretization though a certain refinement is needed in order to obtain suitable results. This article presents a comparative study between XFEM and PD. Therefore, two examples are studied. The first example is crack propagation in a double notched specimen under uniaxial tension with different crack spacings in loading direction. The second example is the specimens with two center cracks. The results show that PD as well as XFEM are well suited to capture this type of behaviour.

关键词： XFEM     peridynamic     bilateral crack     parallel double cracks     nonlocal theory    

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Correlation between tension softening relation and crack extension resistance in concrete

Xiufang ZHANG , Shilang XU ,

《结构与土木工程前沿（英文）》 2009年 第3卷 第3期   页码 323-329 doi: 10.1007/s11709-009-0041-2

摘要： Changes of the material fracture energy consumption with crack propagation can be described by a crack extension resistance curve, one of the fundamental fracture criteria in crack mechanics. Recently, experimental observation of the fracture behavior in concrete was used to develop a new fracture criterion, the crack extension resistance curve, to analyze crack propagation during the entire concrete fracture process. The variation of the crack extension resistance is mainly associated with the energy consumption in the fracture process zone ahead of the stress-free crack tip. The crack extension resistance is then a function of the softening curve, which is a basic mechanical property in the fracture process zone. The relationship between the softening curve and the crack extension resistance curve is then analyzed based on results of three-point bending beams tests. The results indicate that the characteristic points of the crack extension resistance curve is closely related to the characteristic point on used tension softening curve.

关键词： concrete     fracture process zone     crack extension GR resistance     tension softening curve    

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Fracture resistance on aggregate bridging crack in concrete

ZHANG Xiufang, XU Shilang

《结构与土木工程前沿（英文）》 2007年 第1卷 第1期   页码 63-70 doi: 10.1007/s11709-007-0006-2

摘要： Fracture toughening exhibited in quasi-brittle materials such as concrete is often mainly related to the action of aggregate bridging, which leads to the presence of a fracture process zone ahead of stress-free cracks in such materials. In this investigation, the fracture resistance induced by aggregate bridging, denoted by GI-bridging, is the primary focus. In order to quantitatively determine it, a general analytical formula is firstly developed, based on the definition of fracture energy by Hillerborg. After this, we further present the calculated procedures of determining this fracture resistance from the recorded load vs. crack opening displacement curve. Then, both numerical simulations and fracture experiments are performed on concrete three-point bending beams. Utilizing the obtained load against crack opening displacement curve, the value of G at any crack extension as well as the change of G with the crack extension is examined. It is found that G will firstly increase with the development of crack and then stay constant once the initial crack tip opening displacement reaches the characteristic crack opening displacement w0. The effects of material strength and specimen depth on this fracture resistance are also investigated. The results reveal that the values of G of different specimens at any crack propagation are strongly associated with the values of fracture energy of specimens. If the values of fracture energy between different specimens are comparable, the differences between G are ignored. Instead, if values of fracture energy are different, the G will be different. This shows that for specimens with different strengths, G will change greatly whereas for specimens that are different in depth, whether GI-bridging exhibits size effect depends on whether the fracture energy of specimens considered in the calculation of G is assumed to be a size-dependent material parameter.
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Stability and dynamics of rotor system with 45° slant crack on shaft

Yanli LIN, Xiaohui SI, Fulei CHU

《机械工程前沿（英文）》 2011年 第6卷 第2期   页码 203-213 doi: 10.1007/s11465-011-0131-4

摘要：

Crack on a shaft is one of the common damages in a rotor system. In this paper, transverse vibrations are calculated to compare the influences of transverse crack and slant crack on the rotor system. Results show that the vibration amplitude of the rotor system with a 45° slant crack on the shaft is larger than that with a transverse crack when the two types of crack have the same depth and the rotor system runs in the same condition. Stability and dynamic characteristics of the rotor system with a 45° slant crack on the shaft under torsional excitation are analyzed by considering opening and closing of the crack. It is shown that the instability of the transverse vibration of the rotor system increases with increasing difference between the bending stiffness in two main directions, and the vibration is stable when the two bending stiffness are identical. The spectrum analysis of the steady-state response reveals that the gravity and the eccentricity produce different frequency components, and when the two bending stiffness are identical, the multiple frequency components of the torsional excitation disappear. Further investigation shows that the vibration amplitudes in combined frequencies increase rapidly in transversal, torsional, and axial vibration with increasing slant crack depth. The results are helpful for the understanding the dynamic behavior of a rotor system with a slant crack on a shaft and can be used for the detection of the slant crack on a shaft.

关键词： rotor dynamics     slant crack     stability     torsional excitation     open and close    

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Study on the cohesion and adhesion of hot-poured crack sealants

Meng GUO, Yiqiu TAN, Xuesong DU, Zhaofeng LV

《结构与土木工程前沿（英文）》 2017年 第11卷 第3期   页码 353-359 doi: 10.1007/s11709-017-0400-3

摘要： Filling crack sealant is a main method to repair cracking of pavement. The cohesion and adhesion of crack sealant directly determine its service performance and durability. However, the competitive mechanism of cohesion and adhesion failure modes is not clear currently. This research proposed two methods to evaluate cohesion and adhesion of crack sealant, and analyzed the influence of temperature on cohesion and adhesion. The effect of moisture on low-temperature performance of crack sealant was also be evaluated by conducting a soaking test. Results show that with the decrease of temperature, the cohesion force of crack sealant increases significantly, while the adhesion force changes little. There is a critical temperature at which the cohesion force equals the adhesion force. When the temperature is higher, the adhesion force will be greater than cohesion force, and the cohesion failure will happen more easily. In contrast, the adhesion failure will happen more easily when the temperature is lower than the critical value. Soaking in 25 °C water for 24–48 hours will slightly improve the low-temperature tension performance of crack sealant. However, soaking in 60 °C water for 24 hours will decrease the failure energy of low-temperature tension and damage the durability of crack sealant.

关键词： crack sealant     concrete pavement     cohesion     adhesion     moisture damage    

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Bioinspired and biomimetic membranes for water purification and chemical separation: A review

《环境科学与工程前沿（英文）》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1412-8

摘要：

•The history of biological and artificial water channels is reviewed.

关键词： Aquaporins     Artificial water channels     Biomimetic membranes     Chemical separation and water purification    

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Surface modification techniques of membranes to improve their antifouling characteristics: recent advancements

《化学科学与工程前沿（英文）》 2023年 第17卷 第12期   页码 1837-1865 doi: 10.1007/s11705-023-2347-3

摘要： Surface modification techniques of membranes to improve their antifouling characteristics: recent advancements and developments

关键词： Surface modification techniques    

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标题 作者 时间 类型 操作

Metal-organic framework-based CO

Yujie Ban, Meng Zhao, Weishen Yang

期刊论文

Full-band error control and crack-free surface fabrication techniques for ultra-precision fly cutting

F. H. ZHANG, S. F. WANG, C. H. AN, J. WANG, Q. XU

期刊论文

Feasibility of crack free reinforced concrete bridge deck from materials composition perspective: a state

Mahdi AREZOUMANDI

期刊论文

A hypothesis for crack free interior surfaces of Longyou caverns caved in argillaceous siltstone 2000

Zhong Qi YUE, Shaopeng FAN, Zhifa YANG, Lihui LI, Luqing ZHANG, Zhongjian ZHANG,

期刊论文

Recovery of free volume in PIM-1 membranes through alcohol vapor treatment

Faiz Almansour, Monica Alberto, Rupesh S. Bhavsar, Xiaolei Fan, Peter M. Budd, Patricia Gorgojo

期刊论文

Dynamic crack propagation in plates weakened by inclined cracks: an investigation based on peridynamics

A. SHAFIEI

期刊论文

Advancing ion-exchange membranes to ion-selective membranes: principles, status, and opportunities

期刊论文

Imprinted membranes for sustainable separation processes

Laura Donato, Enrico Drioli

期刊论文

Peridynamics versus XFEM: a comparative study for quasi-static crack problems

Jinhai ZHAO, Hesheng TANG, Songtao XUE

期刊论文

Correlation between tension softening relation and crack extension resistance in concrete

Xiufang ZHANG , Shilang XU ,

期刊论文

Fracture resistance on aggregate bridging crack in concrete

ZHANG Xiufang, XU Shilang

期刊论文

Stability and dynamics of rotor system with 45° slant crack on shaft

Yanli LIN, Xiaohui SI, Fulei CHU

期刊论文

Study on the cohesion and adhesion of hot-poured crack sealants

Meng GUO, Yiqiu TAN, Xuesong DU, Zhaofeng LV

期刊论文

Bioinspired and biomimetic membranes for water purification and chemical separation: A review

期刊论文

Surface modification techniques of membranes to improve their antifouling characteristics: recent advancements

期刊论文