Soil cement bentonite(SCB)is a common material for constructing vertical cutoff walls to prevent groundwater migration at contaminated industrial sites.However,site contaminants can degrade the durability of the cutof...Soil cement bentonite(SCB)is a common material for constructing vertical cutoff walls to prevent groundwater migration at contaminated industrial sites.However,site contaminants can degrade the durability of the cutoff wall.To enhance its performance,this study developed a silica fume-SCB(SSCB).The macroscopic and microscopic properties of SSCB were assessed by unconfined compressive strength test,variable head permeability test,X-ray diffraction(XRD),scanning electron microscopy(SEM)and nuclear magnetic resonance(NMR)spectroscopy.The correlation between its multi-scale properties was analyzed based on pore characteristics.The results indicate that increasing the silica fume substitution ratio improved SSCB strength,especially in the middle and late curing stages.Moreover,increasing the substitution ratio decreased SSCB permeability coefficient,with a more pronounced effect in earlier curing stages.Silica fume addition also refined SSCB pore structure and reduced its porosity.The fractal dimension was used to quantify SSCB pore structure complexity.Increasing silica fume content reduced small pore fractal dimension in SSCB.Concurrently,SSCB strength increased and SSCB permeability coefficient decreased.The findings of this research will demonstrate the great potential of SSCB backfill for practical applications.展开更多
The pressure-preserving controller is the core part of deep in-situ pressure-preserving coring(IPP-Coring) system, and its pressure-preserving capability is the key to IPP-Coring technology. To achieve a good understa...The pressure-preserving controller is the core part of deep in-situ pressure-preserving coring(IPP-Coring) system, and its pressure-preserving capability is the key to IPP-Coring technology. To achieve a good understanding of the influence of mechanical properties of materials on the ultimate pressure-bearing capability(UPB-Capability) of the pressure-preserving controller, the IPP-Coring experimental platform was developed to test the UPB-Capability of pressure-preserving controllers of four different materials. The experimental results show that the UPB-Capability of pressure-preserving controllers with different material varies greatly. A numerical model of the pressure-preserving controller was developed to study the influences of mechanical parameters of materials on the UPB-Capability of the pressurepreserving controller after the accuracy of the numerical model is verified by experiments. The results indicate that the yield strength(YS) and Poisson's ratio(PR) of the material have little effect on the UPB-Capability of the pressure-preserving controller, whereas the elastic modulus(EM) of the material has a significant effect. A generalized model of the UPB-Capability of the pressure-preserving controller is developed to reveal the mechanism of the influence of material properties on the UPB-Capability of the pressure-preserving controllers. Considering these results, the future optimization direction of the pressure-preserving controller and material selection scheme in practical engineering applications of the pressure-preserving controller are suggested.展开更多
Tunnel Boring Machines(TBMs)are vital for tunnel and underground construction due to their high safety and efficiency.Accurately predicting TBM operational parameters based on the surrounding environment is crucial fo...Tunnel Boring Machines(TBMs)are vital for tunnel and underground construction due to their high safety and efficiency.Accurately predicting TBM operational parameters based on the surrounding environment is crucial for planning schedules and managing costs.This study investigates the effectiveness of tree-based machine learning models,including Random Forest,Extremely Randomized Trees,Adaptive Boosting Machine,Gradient Boosting Machine,Extreme Gradient Boosting Machine(XGBoost),Light Gradient Boosting Machine,and CatBoost,in predicting the Penetration Rate(PR)of TBMs by considering rock mass and material characteristics.These techniques are able to provide a good relationship between input(s)and output parameters;hence,obtaining a high level of accuracy.To do that,a comprehensive database comprising various rock mass and material parameters,including Rock Mass Rating,Brazilian Tensile Strength,and Weathering Zone,was utilized for model development.The practical application of these models was assessed with a new dataset representing diverse rock mass and material properties.To evaluate model performance,ranking systems and Taylor diagrams were employed.CatBoost emerged as the most accurate model during training and testing,with R2 scores of 0.927 and 0.861,respectively.However,during validation,XGBoost demonstrated superior performance with an R2 of 0.713.Despite these variations,all tree-based models showed promising accuracy in predicting TBM performance,providing valuable insights for similar projects in the future.展开更多
Accumulative roll bonding(ARB)is a severe plastic deformation method to prepare the metallic composite material by physical method at room to elevate temperature,without the generation of additional waste solid or gas...Accumulative roll bonding(ARB)is a severe plastic deformation method to prepare the metallic composite material by physical method at room to elevate temperature,without the generation of additional waste solid or gas.With the physical characteristicsmulti-material and hybrid structure,the mechanical and function properties of the ARB composite material,like Al/steel,Al/Mg,Al/Cu,etc.,shall have the"1+1>2"effect on the mechanical and functional properties,including the remarkable properties that include lightweight,high strength,thermal/electrical conductivity,electromagnetic shielding,and other functions.To deeply investigate the preparation method and microstructural evolution of various metal laminates by ARB,as well as the mechanical and functional properties of the laminate,an overview of the history of ARB technique,the breakthrough of ARB sheet properties,as well as the relative products in industries is provided.Addi-tionally,the future development of ARB technology and the utilization of composite materials in different areas will be discussed.展开更多
[ Objective] The research aimed to study effects of material physical properties on white-rot fungi mycelial growth and provide theoretical basis for further expanding the application range of white-rot fungi. [ Metho...[ Objective] The research aimed to study effects of material physical properties on white-rot fungi mycelial growth and provide theoretical basis for further expanding the application range of white-rot fungi. [ Method Four common species of white-rot fungi were cultivated by wood meal fowl dung mixture in test tube and culture dishes. The relationship between physical properties of culture material and the growth of these mycelials were studied. [Result] The results showed the water retention capacity of culture material was decreased with the increasing of its grain size and porosity, but the decrease of its specific gravity reduced the material water retention. And the dehydration rate of medium prepared with these materials at the same moisture conditions tended to increase. These physical properties of material, such as grain size, specific gravity, porosity, water retention and water drainage, influenced the growth of white-rot fungi mycelial by affecting the moisture and ventilation condition of media. The results hinted that above material physical properties had feedback effects on the growth of white-rot fungi mycelia. [ Conclution] Physical properties of culture material have significant effects on the growth of white-rot fungi mycelial.展开更多
Only two macroscopic parameters are needed to describe the mechanical properties of linear elastic solids, i.e. the Poisson＇s ratio and Young＇s modulus. Correspondingly, there should be two microscopic parameters to...Only two macroscopic parameters are needed to describe the mechanical properties of linear elastic solids, i.e. the Poisson＇s ratio and Young＇s modulus. Correspondingly, there should be two microscopic parameters to determine the mechanical properties of material if the macroscopic mechanical properties of linear elastic solids are derived from the microscopic level. Enlightened by this idea, a multiscale mechanical model for material, the virtual multi-dimensional internal bonds （VMIB） model, is proposed by incorporating a shear bond into the virtual internal bond （VIB） model. By this modification, the VMIB model associates the macro mechanical properties of material with the microscopic mechanical properties of discrete structure and the corresponding relationship between micro and macro parameters is derived. The tensor quality of the energy density function, which contains coordinate vector, is mathematically proved. From the point of view of VMIB, the macroscopic nonlinear behaviors of material could be attributed to the evolution of virtual bond distribution density induced by the imposed deformation. With this theoretical hypothesis, as an application example, a uniaxial compressive failure of brittle material is simulated. Good agreement between the experimental results and the simulated ones is found.展开更多
Statistical manipulation of material data was conducted for probabilistic life assessment or risk-based design and maintenance for high temperature components of power plants. To obtain the statistical distribution of...Statistical manipulation of material data was conducted for probabilistic life assessment or risk-based design and maintenance for high temperature components of power plants. To obtain the statistical distribution of material properties, dominant parameters affecting material properties are introduced into normalization of statistical variables. Those parameters are hardness, chemical composition, characteristic micro structural features and so on. Creep and fatigue properties are expressed by normalized parameters and the unified statistical distributions are obtained. These probability distribution functions show good coincidence statistically with the field database of steam turbine components. It was concluded that the unified statistical baseline approach is useful for the risk management of components in power plants.展开更多
The properties and tensile behaviors of polypropylene (PP) geogrids and geonets for reinforcement of soil structures are investigated.Mass per unit area of the geogrids and geonets was weighed using an electronic bala...The properties and tensile behaviors of polypropylene (PP) geogrids and geonets for reinforcement of soil structures are investigated.Mass per unit area of the geogrids and geonets was weighed using an electronic balance and aperture sizes of the geonets were exactly measured using a computer.Laboratory tests were performed using a small tensile machine capable of monitoring tensile force and displacement.Tensile failure behaviors were described,and tensile index properties such as tensile strength,maximum tensile strain,tensile forces corresponding to different strains in the geogrids and gronets were obtained.The characterization of these indexes is discussed.展开更多
Materials have driven human progress from the Stone Age to the Silicon Age;and a new age of multifunctional assembled materials is coming.Designing these materials with precisely tailored properties is essential to so...Materials have driven human progress from the Stone Age to the Silicon Age;and a new age of multifunctional assembled materials is coming.Designing these materials with precisely tailored properties is essential to solve problems that the current generation of materials cannot handle.This approach will facilitate the development of scalable multifunctional material systems and devices.展开更多
Polylactic acid,a biodegradable polymer derived from renewable resources,is increasingly used in food packaging due to its transparency,renewability,and food safety.However,its mechanical properties,heat resistance,an...Polylactic acid,a biodegradable polymer derived from renewable resources,is increasingly used in food packaging due to its transparency,renewability,and food safety.However,its mechanical properties,heat resistance,and barrier performance present significant challenges that limit its application.Currently,there is a lack of comprehensive literature addressing methods to optimize polylactic acid’s performance for various food packaging application.Hence,this review provides an overview of polylactic acid production processes,including the synthesis of lactic acid and lactide,as well as methods such as polycondensation and ring-opening polymerization.We critically examine the advantages and limitations of polylactic acid in various food packaging contexts,focusing on strategies to enhance its mechanical properties,barrier performance against oxygen and water vapor,surface hydrophobicity,thermal stability,and resistance to ultraviolet light.Furthermore,we summarize recent advancements in polylactic acid applications for food packaging,highlighting innovations in antioxidant,antimicrobial,and freshness indicator packaging.These developments underscore the significant potential of polylactic acid in the food packaging sector and offer valuable insights for future research directions.展开更多
The screening of novel materials with good performance and the modelling of quantitative structureactivity relationships(QSARs),among other issues,are hot topics in the field of materials science.Traditional experimen...The screening of novel materials with good performance and the modelling of quantitative structureactivity relationships(QSARs),among other issues,are hot topics in the field of materials science.Traditional experiments and computational modelling often consume tremendous time and resources and are limited by their experimental conditions and theoretical foundations.Thus,it is imperative to develop a new method of accelerating the discovery and design process for novel materials.Recently,materials discovery and design using machine learning have been receiving increasing attention and have achieved great improvements in both time efficiency and prediction accuracy.In this review,we first outline the typical mode of and basic procedures for applying machine learning in materials science,and we classify and compare the main algorithms.Then,the current research status is reviewed with regard to applications of machine learning in material property prediction,in new materials discovery and for other purposes.Finally,we discuss problems related to machine learning in materials science,propose possible solutions,and forecast potential directions of future research.By directly combining computational studies with experiments,we hope to provide insight into the parameters that affect the properties of materials,thereby enabling more efficient and target-oriented research on materials discovery and design.展开更多
The first author proposed the concept of the cemented material dam （CMD） in 2009. This concept was aimed at building an environmentally friendly dam in a safer and more economical way for both the dam and the area d...The first author proposed the concept of the cemented material dam （CMD） in 2009. This concept was aimed at building an environmentally friendly dam in a safer and more economical way for both the dam and the area downstream. The concept covers the cemented sand, gravel, and rock dam （CSGRD）, the rockfill concrete （RFC） dam （or the cemented rockfill dam, CRD）, and the cemented soil dam （CSD）. This paper summarizes the concept and principles of the CMD based on studies and practices in projects around the world. It also introduces new developments in the CSGRD, CRD, and CSD.展开更多
Material properties of blank have a great effect on power spinning process of aluminum alloy parts with transverse inner rib.By using finite element(FE) and Taguchi method,the effects and significance of five key mate...Material properties of blank have a great effect on power spinning process of aluminum alloy parts with transverse inner rib.By using finite element(FE) and Taguchi method,the effects and significance of five key material parameters,namely,anisotropic index in thickness direction,yield strength,hardening exponent,strengthening factor and elastic modulus on the formability of inner rib,tendency of wall fracture and degree of inhomogeneous deformation of finished spun parts were obtained.The achievements provide an important guide for selecting reasonable spinning material,and are very significant for the optimum design and precision control of power spinning process of parts with transverse inner rib.展开更多
This study aims at proposing a reasonable roughness parameter that can reflect the peak shear strength(PSS)of rock joints.Firstly,the contribution of the asperities with different apparent dip angles to shear strength...This study aims at proposing a reasonable roughness parameter that can reflect the peak shear strength(PSS)of rock joints.Firstly,the contribution of the asperities with different apparent dip angles to shear strength is studied.Then the shear strength of the entire joint asperities is derived.The results showed that the PSS of the entire joint asperities is proportional to a key parameter hs,which is related to the geometric character of the joint surface and the joint material properties.The parameter hsis taken as the new roughness parameter,and it is reasonable to associate the PSS with the geometric characteristics of the joint surface.Based on the new roughness parameter and shear test results of 20 sets of joint specimens,a new PSS model for rock joints is proposed.The new model is validated with the artificial joints in this paper and real rock joints in published studies.Results showed that it is suitable for different types of rock joints except for gneiss joints.The new model has the form of the Mohr-Coulomb model,which can directly reflect the relationship between the 3 D roughness parameters and the peak dilation angle.展开更多
La1-xSrxGa1-y MgyO3-δ(LSGM) electrolyte, La1-xSrxCr1-y MnyO3-δ( LSCM ) anode and La1-xSrxFe1-y MnyO3-aaaaaaa(LSFM) cathode materials were all synthesized by glycine-nitrate process (GNP). The microstructure and char...La1-xSrxGa1-y MgyO3-δ(LSGM) electrolyte, La1-xSrxCr1-y MnyO3-δ( LSCM ) anode and La1-xSrxFe1-y MnyO3-aaaaaaa(LSFM) cathode materials were all synthesized by glycine-nitrate process (GNP). The microstructure and characteristics of LSGM, LSCM and LSFM were tested via X-ray diffraction(XRD), scanning electron microcopy (SEM), A C impedance and four-probe direct current techniques. XRD shows that pure perovskite phase LSGM electrolyte and electrode (LSCM anode and LSFM cathode) materials were prepared after being sintered at 1400℃for 20 h and at 1000℃for 5 h, respectively. The max conductivities of LSGM (ionic conductivity), LSCM (total conductivity) and LSFM (total conductivity) materials are 0.02, 10, 16 S·cm-1 in the air below 850℃, respectively. The conductivity of LSCM becomes smaller when the atmosphere changes from air to pure hydrogen at the same temperature and it decreases with the temperature like metal. The porous and LSGM-based LSCM anode and LSFM cathode films were prepared by screen printing method, and the sintering temperatures for them were 1300 and 1250℃, respectively. LSGM and electrode (LSCM and LSFM) materials have good thermal and chemical compatibility.展开更多
Representative volume element （RVE） method and asymptotic homogenization （AH） method are two widely used methods in predicting effective properties of pe- riodic materials. This paper develops a novel implementa- ...Representative volume element （RVE） method and asymptotic homogenization （AH） method are two widely used methods in predicting effective properties of pe- riodic materials. This paper develops a novel implementa- tion of the AH method, which has rigorous mathematical foundation of the AH method, and also simplicity as the RVE method. This implementation can be easily realized using commercial software as a black box, and can use all kinds of elements available in commercial software to model unit cells with rather complicated microstructures, so the model may remain a fairly small scale. Several examples were car- fled out to demonstrate the simplicity and effectiveness of the new implementation.展开更多
Materials science is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This scientific field investigates the relationship between the structure of materials at ...Materials science is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates elements of applied physics and chemistry. With significant media attention focused on nanoscience and nanotechnology in recent years, materials science has been propelled to the forefront at many universities. Materials science encompasses various classes of materials, including electronic materials, functional ceramics, magnesium, material and processes for flat-panel displays, eco/environmental materials, sustainable energy materials, transportation materials, electronic packaging materials, etc.展开更多
We compare the factors which affect the movement of Tibetan Plateau by building three types of finite element models： an elastic materials （M-EC）, a continuous model composed by non-linear materials （M-PC）, and a...We compare the factors which affect the movement of Tibetan Plateau by building three types of finite element models： an elastic materials （M-EC）, a continuous model composed by non-linear materials （M-PC）, and an elastic model with discontinuous fault movements （M-ET）. Both in M-ET and M-EC, the materials in Qiangtang and Lhasa block are elastic, and in M-ET, discontinuous movement of faults is considered for evaluating the effects of strike-slip faults. In model M-PC Druker-Prager plastic materials are used in Qiangtang and Lhasa block. Comparisons of the numerical simulation and the GPS observations show following characteristics： （1） Under present tectonic environment, short-term deformation of Tibetan Plateau can be simulated well by elastic models; （2） Discontinuous fault activities increase the lateral extrusion of the eastern part of Tibetan Plateau, reduce the stress field level in Qiangtang, Tarim and Qaidam blocks and strengthen the E-W extensional force in the east and the west parts of Qiangtang block; （3） Properties of plastic materials reduce the total stress field and the E-W extensional force, thus, the normal fault earthquakes in southern Tibet is mainly owed to the effect of active fault movement. Based on the numerical simulations we speculate that faults movement may play a more important role on the kinematic pattern of Tibetan Plateau than bulk properties.展开更多
Hybrid materials incorporating Eu-(TTA)(3). 2H(2)O (7hereafter designated as Eu-TTA, with TTA: thenoyltrifluoroacetone) in unmodified or modified MCM-41 by 3-aminopropyl-triethoxysilane (APTES) were prepared by impreg...Hybrid materials incorporating Eu-(TTA)(3). 2H(2)O (7hereafter designated as Eu-TTA, with TTA: thenoyltrifluoroacetone) in unmodified or modified MCM-41 by 3-aminopropyl-triethoxysilane (APTES) were prepared by impregnation method. The obtained materials were characterized using X-ray diffraction (XRD), IR and diffuse reflectance spectroscopy and luminescence spectra. All the hybrid samples exhibited the characteristic emission bands of EU3+ under UV light excitation at room temperature, and the excitation spectra showed significant blue-shifts compared to the pure rare-earth complex. Although the red emission intensity in the modified hybrid was almost the half of the red emission intensity in the pure Eu-TTA complex at room temperature, the hybrid showed a much higher thermal stability due to the shielding character of the MCM-41 host.展开更多
In this paper, we present a new united approach to formulate the equivalent micropolar constitutive relation of two-dimensional（2-D） periodic cellular material to capture its non-local properties and to explain the ...In this paper, we present a new united approach to formulate the equivalent micropolar constitutive relation of two-dimensional（2-D） periodic cellular material to capture its non-local properties and to explain the size effects in its structural analysis. The new united approach takes both the displacement compatibility and the equilibrium of forces and moments into consideration, where Taylor series expansion of the displacement and rotation fields and the extended averaging procedure with an explicit enforcement of equilibrium are adopted in the micromechanical analysis of a unit cell.In numerical examples, the effective micropolar constants obtained in this paper and others derived in the literature are used for the equivalent micropolar continuum simulation of cellular solids. The solutions from the equivalent analysis are compared with the discrete simulation solutions of the cellular solids. It is found that the micropolar constants developed in this paper give satisfying results of equivalent analysis for the periodic cellular material.展开更多
基金Project(2019YFC1803601)supported by the National Key Research and Development Program of ChinaProject(52274182)supported by the National Natural Science Foundation of China+1 种基金Project(2021zzts0274)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(CX20210295)supported by the Postgraduate Scientific Research Innovation Project of Hunan Province,China。
文摘Soil cement bentonite(SCB)is a common material for constructing vertical cutoff walls to prevent groundwater migration at contaminated industrial sites.However,site contaminants can degrade the durability of the cutoff wall.To enhance its performance,this study developed a silica fume-SCB(SSCB).The macroscopic and microscopic properties of SSCB were assessed by unconfined compressive strength test,variable head permeability test,X-ray diffraction(XRD),scanning electron microscopy(SEM)and nuclear magnetic resonance(NMR)spectroscopy.The correlation between its multi-scale properties was analyzed based on pore characteristics.The results indicate that increasing the silica fume substitution ratio improved SSCB strength,especially in the middle and late curing stages.Moreover,increasing the substitution ratio decreased SSCB permeability coefficient,with a more pronounced effect in earlier curing stages.Silica fume addition also refined SSCB pore structure and reduced its porosity.The fractal dimension was used to quantify SSCB pore structure complexity.Increasing silica fume content reduced small pore fractal dimension in SSCB.Concurrently,SSCB strength increased and SSCB permeability coefficient decreased.The findings of this research will demonstrate the great potential of SSCB backfill for practical applications.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 52225403, 52304146, 51827901)Sichuan Science and Technology Program (2023NSFSC0919)。
文摘The pressure-preserving controller is the core part of deep in-situ pressure-preserving coring(IPP-Coring) system, and its pressure-preserving capability is the key to IPP-Coring technology. To achieve a good understanding of the influence of mechanical properties of materials on the ultimate pressure-bearing capability(UPB-Capability) of the pressure-preserving controller, the IPP-Coring experimental platform was developed to test the UPB-Capability of pressure-preserving controllers of four different materials. The experimental results show that the UPB-Capability of pressure-preserving controllers with different material varies greatly. A numerical model of the pressure-preserving controller was developed to study the influences of mechanical parameters of materials on the UPB-Capability of the pressurepreserving controller after the accuracy of the numerical model is verified by experiments. The results indicate that the yield strength(YS) and Poisson's ratio(PR) of the material have little effect on the UPB-Capability of the pressure-preserving controller, whereas the elastic modulus(EM) of the material has a significant effect. A generalized model of the UPB-Capability of the pressure-preserving controller is developed to reveal the mechanism of the influence of material properties on the UPB-Capability of the pressure-preserving controllers. Considering these results, the future optimization direction of the pressure-preserving controller and material selection scheme in practical engineering applications of the pressure-preserving controller are suggested.
文摘Tunnel Boring Machines(TBMs)are vital for tunnel and underground construction due to their high safety and efficiency.Accurately predicting TBM operational parameters based on the surrounding environment is crucial for planning schedules and managing costs.This study investigates the effectiveness of tree-based machine learning models,including Random Forest,Extremely Randomized Trees,Adaptive Boosting Machine,Gradient Boosting Machine,Extreme Gradient Boosting Machine(XGBoost),Light Gradient Boosting Machine,and CatBoost,in predicting the Penetration Rate(PR)of TBMs by considering rock mass and material characteristics.These techniques are able to provide a good relationship between input(s)and output parameters;hence,obtaining a high level of accuracy.To do that,a comprehensive database comprising various rock mass and material parameters,including Rock Mass Rating,Brazilian Tensile Strength,and Weathering Zone,was utilized for model development.The practical application of these models was assessed with a new dataset representing diverse rock mass and material properties.To evaluate model performance,ranking systems and Taylor diagrams were employed.CatBoost emerged as the most accurate model during training and testing,with R2 scores of 0.927 and 0.861,respectively.However,during validation,XGBoost demonstrated superior performance with an R2 of 0.713.Despite these variations,all tree-based models showed promising accuracy in predicting TBM performance,providing valuable insights for similar projects in the future.
基金supported by Special Topic of the Industrialization of Scientific and Technological Achievements from Hong Kong and Macao to Guangdong Province(Grant No.2023A0505030002)Shenzhen-Hong Kong-Macao Sciencaend Technology Program(Category C)(Grant No.SGDX20220530111402013)+2 种基金Department of Science and Technology of Guangdong Province(Grant No.2022A0505050081)the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030006)the Guangdong Academy of Science Fund(Grant No.2020GDASYL-20200101001).
文摘Accumulative roll bonding(ARB)is a severe plastic deformation method to prepare the metallic composite material by physical method at room to elevate temperature,without the generation of additional waste solid or gas.With the physical characteristicsmulti-material and hybrid structure,the mechanical and function properties of the ARB composite material,like Al/steel,Al/Mg,Al/Cu,etc.,shall have the"1+1>2"effect on the mechanical and functional properties,including the remarkable properties that include lightweight,high strength,thermal/electrical conductivity,electromagnetic shielding,and other functions.To deeply investigate the preparation method and microstructural evolution of various metal laminates by ARB,as well as the mechanical and functional properties of the laminate,an overview of the history of ARB technique,the breakthrough of ARB sheet properties,as well as the relative products in industries is provided.Addi-tionally,the future development of ARB technology and the utilization of composite materials in different areas will be discussed.
基金Supported by Qian Jiang Manpower Program of Zhejiang Province Science and Technology Department (No.2007R10039)National Basic Research Program of China (No.2005CB724204)Under-graduate Technology Innovation Program of Zhejiang Province~~
文摘[ Objective] The research aimed to study effects of material physical properties on white-rot fungi mycelial growth and provide theoretical basis for further expanding the application range of white-rot fungi. [ Method Four common species of white-rot fungi were cultivated by wood meal fowl dung mixture in test tube and culture dishes. The relationship between physical properties of culture material and the growth of these mycelials were studied. [Result] The results showed the water retention capacity of culture material was decreased with the increasing of its grain size and porosity, but the decrease of its specific gravity reduced the material water retention. And the dehydration rate of medium prepared with these materials at the same moisture conditions tended to increase. These physical properties of material, such as grain size, specific gravity, porosity, water retention and water drainage, influenced the growth of white-rot fungi mycelial by affecting the moisture and ventilation condition of media. The results hinted that above material physical properties had feedback effects on the growth of white-rot fungi mycelia. [ Conclution] Physical properties of culture material have significant effects on the growth of white-rot fungi mycelial.
基金Project supported by the National Basic Research Program of China (973 Project) (No. 2002CB412704).
文摘Only two macroscopic parameters are needed to describe the mechanical properties of linear elastic solids, i.e. the Poisson＇s ratio and Young＇s modulus. Correspondingly, there should be two microscopic parameters to determine the mechanical properties of material if the macroscopic mechanical properties of linear elastic solids are derived from the microscopic level. Enlightened by this idea, a multiscale mechanical model for material, the virtual multi-dimensional internal bonds （VMIB） model, is proposed by incorporating a shear bond into the virtual internal bond （VIB） model. By this modification, the VMIB model associates the macro mechanical properties of material with the microscopic mechanical properties of discrete structure and the corresponding relationship between micro and macro parameters is derived. The tensor quality of the energy density function, which contains coordinate vector, is mathematically proved. From the point of view of VMIB, the macroscopic nonlinear behaviors of material could be attributed to the evolution of virtual bond distribution density induced by the imposed deformation. With this theoretical hypothesis, as an application example, a uniaxial compressive failure of brittle material is simulated. Good agreement between the experimental results and the simulated ones is found.
文摘Statistical manipulation of material data was conducted for probabilistic life assessment or risk-based design and maintenance for high temperature components of power plants. To obtain the statistical distribution of material properties, dominant parameters affecting material properties are introduced into normalization of statistical variables. Those parameters are hardness, chemical composition, characteristic micro structural features and so on. Creep and fatigue properties are expressed by normalized parameters and the unified statistical distributions are obtained. These probability distribution functions show good coincidence statistically with the field database of steam turbine components. It was concluded that the unified statistical baseline approach is useful for the risk management of components in power plants.
文摘The properties and tensile behaviors of polypropylene (PP) geogrids and geonets for reinforcement of soil structures are investigated.Mass per unit area of the geogrids and geonets was weighed using an electronic balance and aperture sizes of the geonets were exactly measured using a computer.Laboratory tests were performed using a small tensile machine capable of monitoring tensile force and displacement.Tensile failure behaviors were described,and tensile index properties such as tensile strength,maximum tensile strain,tensile forces corresponding to different strains in the geogrids and gronets were obtained.The characterization of these indexes is discussed.
文摘Materials have driven human progress from the Stone Age to the Silicon Age;and a new age of multifunctional assembled materials is coming.Designing these materials with precisely tailored properties is essential to solve problems that the current generation of materials cannot handle.This approach will facilitate the development of scalable multifunctional material systems and devices.
基金supported by the“14th Five-Year Plan”National Key Research and Development Plan Project(Grant No.2023YFE0105500)support of the collaborative project titled‘Research and Application of High Transparent and High Strength Degradable Polylactic Acid(PLA)Membrane’(Contract No.2023-0166)with Wuhan Hongzhicai Packaging and Printing Company。
文摘Polylactic acid,a biodegradable polymer derived from renewable resources,is increasingly used in food packaging due to its transparency,renewability,and food safety.However,its mechanical properties,heat resistance,and barrier performance present significant challenges that limit its application.Currently,there is a lack of comprehensive literature addressing methods to optimize polylactic acid’s performance for various food packaging application.Hence,this review provides an overview of polylactic acid production processes,including the synthesis of lactic acid and lactide,as well as methods such as polycondensation and ring-opening polymerization.We critically examine the advantages and limitations of polylactic acid in various food packaging contexts,focusing on strategies to enhance its mechanical properties,barrier performance against oxygen and water vapor,surface hydrophobicity,thermal stability,and resistance to ultraviolet light.Furthermore,we summarize recent advancements in polylactic acid applications for food packaging,highlighting innovations in antioxidant,antimicrobial,and freshness indicator packaging.These developments underscore the significant potential of polylactic acid in the food packaging sector and offer valuable insights for future research directions.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.U1630134,51622207 and 51372228)the National Key Research and Development Program of China(Grant Nos.2017YFB0701600 and 2017YFB0701500)+2 种基金the Shanghai Institute of Materials Genome from the Shanghai Municipal Science and Technology Commission(Grant No.14DZ2261200)the Shanghai Municipal Education Commission(Grant No.14ZZ099)the Natural Science Foundation of Shanghai(Grant No.16ZR1411200).
文摘The screening of novel materials with good performance and the modelling of quantitative structureactivity relationships(QSARs),among other issues,are hot topics in the field of materials science.Traditional experiments and computational modelling often consume tremendous time and resources and are limited by their experimental conditions and theoretical foundations.Thus,it is imperative to develop a new method of accelerating the discovery and design process for novel materials.Recently,materials discovery and design using machine learning have been receiving increasing attention and have achieved great improvements in both time efficiency and prediction accuracy.In this review,we first outline the typical mode of and basic procedures for applying machine learning in materials science,and we classify and compare the main algorithms.Then,the current research status is reviewed with regard to applications of machine learning in material property prediction,in new materials discovery and for other purposes.Finally,we discuss problems related to machine learning in materials science,propose possible solutions,and forecast potential directions of future research.By directly combining computational studies with experiments,we hope to provide insight into the parameters that affect the properties of materials,thereby enabling more efficient and target-oriented research on materials discovery and design.
文摘The first author proposed the concept of the cemented material dam （CMD） in 2009. This concept was aimed at building an environmentally friendly dam in a safer and more economical way for both the dam and the area downstream. The concept covers the cemented sand, gravel, and rock dam （CSGRD）, the rockfill concrete （RFC） dam （or the cemented rockfill dam, CRD）, and the cemented soil dam （CSD）. This paper summarizes the concept and principles of the CMD based on studies and practices in projects around the world. It also introduces new developments in the CSGRD, CRD, and CSD.
基金Projects(50405039,50575186) supported by the National Natural Science Foundation of ChinaProject(50225518) supported by the National Natural Science Foundation of China for Distinguished Young ScholarsProject(2008AA04Z122) supported by the National High-tech Research and Development Program of China
文摘Material properties of blank have a great effect on power spinning process of aluminum alloy parts with transverse inner rib.By using finite element(FE) and Taguchi method,the effects and significance of five key material parameters,namely,anisotropic index in thickness direction,yield strength,hardening exponent,strengthening factor and elastic modulus on the formability of inner rib,tendency of wall fracture and degree of inhomogeneous deformation of finished spun parts were obtained.The achievements provide an important guide for selecting reasonable spinning material,and are very significant for the optimum design and precision control of power spinning process of parts with transverse inner rib.
基金supported by China Postdoctoral Science Foundation(No.2020M680007)Beijing Postdoctoral Research Foundation(No.2020-zz-087)+1 种基金National Natural Science Foundation of China(Nos.51478027 and 51174012)Fundamental Research Funds for Beijing Civil Engineering and Architecture(No.X20031)。
文摘This study aims at proposing a reasonable roughness parameter that can reflect the peak shear strength(PSS)of rock joints.Firstly,the contribution of the asperities with different apparent dip angles to shear strength is studied.Then the shear strength of the entire joint asperities is derived.The results showed that the PSS of the entire joint asperities is proportional to a key parameter hs,which is related to the geometric character of the joint surface and the joint material properties.The parameter hsis taken as the new roughness parameter,and it is reasonable to associate the PSS with the geometric characteristics of the joint surface.Based on the new roughness parameter and shear test results of 20 sets of joint specimens,a new PSS model for rock joints is proposed.The new model is validated with the artificial joints in this paper and real rock joints in published studies.Results showed that it is suitable for different types of rock joints except for gneiss joints.The new model has the form of the Mohr-Coulomb model,which can directly reflect the relationship between the 3 D roughness parameters and the peak dilation angle.
基金Project supported by the National Natural Science Foundation of China (50204007)the Foundation of Yunnan Province (2005PY01-33)
文摘La1-xSrxGa1-y MgyO3-δ(LSGM) electrolyte, La1-xSrxCr1-y MnyO3-δ( LSCM ) anode and La1-xSrxFe1-y MnyO3-aaaaaaa(LSFM) cathode materials were all synthesized by glycine-nitrate process (GNP). The microstructure and characteristics of LSGM, LSCM and LSFM were tested via X-ray diffraction(XRD), scanning electron microcopy (SEM), A C impedance and four-probe direct current techniques. XRD shows that pure perovskite phase LSGM electrolyte and electrode (LSCM anode and LSFM cathode) materials were prepared after being sintered at 1400℃for 20 h and at 1000℃for 5 h, respectively. The max conductivities of LSGM (ionic conductivity), LSCM (total conductivity) and LSFM (total conductivity) materials are 0.02, 10, 16 S·cm-1 in the air below 850℃, respectively. The conductivity of LSCM becomes smaller when the atmosphere changes from air to pure hydrogen at the same temperature and it decreases with the temperature like metal. The porous and LSGM-based LSCM anode and LSFM cathode films were prepared by screen printing method, and the sintering temperatures for them were 1300 and 1250℃, respectively. LSGM and electrode (LSCM and LSFM) materials have good thermal and chemical compatibility.
基金supported by the National Natural Science Foundation of China(91216201)
文摘Representative volume element （RVE） method and asymptotic homogenization （AH） method are two widely used methods in predicting effective properties of pe- riodic materials. This paper develops a novel implementa- tion of the AH method, which has rigorous mathematical foundation of the AH method, and also simplicity as the RVE method. This implementation can be easily realized using commercial software as a black box, and can use all kinds of elements available in commercial software to model unit cells with rather complicated microstructures, so the model may remain a fairly small scale. Several examples were car- fled out to demonstrate the simplicity and effectiveness of the new implementation.
文摘Materials science is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates elements of applied physics and chemistry. With significant media attention focused on nanoscience and nanotechnology in recent years, materials science has been propelled to the forefront at many universities. Materials science encompasses various classes of materials, including electronic materials, functional ceramics, magnesium, material and processes for flat-panel displays, eco/environmental materials, sustainable energy materials, transportation materials, electronic packaging materials, etc.
基金jointly supported by Chinese Academy of Sciences(Nos.KZCX2-YW-116 and KZCX2-YW-142)National Natural Science Foundation of China (Nos.40974034and 40064004)
文摘We compare the factors which affect the movement of Tibetan Plateau by building three types of finite element models： an elastic materials （M-EC）, a continuous model composed by non-linear materials （M-PC）, and an elastic model with discontinuous fault movements （M-ET）. Both in M-ET and M-EC, the materials in Qiangtang and Lhasa block are elastic, and in M-ET, discontinuous movement of faults is considered for evaluating the effects of strike-slip faults. In model M-PC Druker-Prager plastic materials are used in Qiangtang and Lhasa block. Comparisons of the numerical simulation and the GPS observations show following characteristics： （1） Under present tectonic environment, short-term deformation of Tibetan Plateau can be simulated well by elastic models; （2） Discontinuous fault activities increase the lateral extrusion of the eastern part of Tibetan Plateau, reduce the stress field level in Qiangtang, Tarim and Qaidam blocks and strengthen the E-W extensional force in the east and the west parts of Qiangtang block; （3） Properties of plastic materials reduce the total stress field and the E-W extensional force, thus, the normal fault earthquakes in southern Tibet is mainly owed to the effect of active fault movement. Based on the numerical simulations we speculate that faults movement may play a more important role on the kinematic pattern of Tibetan Plateau than bulk properties.
基金financial supportfrom PRAMX 98-05 and helpful discussion with Dr.A.C.Franville.
文摘Hybrid materials incorporating Eu-(TTA)(3). 2H(2)O (7hereafter designated as Eu-TTA, with TTA: thenoyltrifluoroacetone) in unmodified or modified MCM-41 by 3-aminopropyl-triethoxysilane (APTES) were prepared by impregnation method. The obtained materials were characterized using X-ray diffraction (XRD), IR and diffuse reflectance spectroscopy and luminescence spectra. All the hybrid samples exhibited the characteristic emission bands of EU3+ under UV light excitation at room temperature, and the excitation spectra showed significant blue-shifts compared to the pure rare-earth complex. Although the red emission intensity in the modified hybrid was almost the half of the red emission intensity in the pure Eu-TTA complex at room temperature, the hybrid showed a much higher thermal stability due to the shielding character of the MCM-41 host.
文摘In this paper, we present a new united approach to formulate the equivalent micropolar constitutive relation of two-dimensional（2-D） periodic cellular material to capture its non-local properties and to explain the size effects in its structural analysis. The new united approach takes both the displacement compatibility and the equilibrium of forces and moments into consideration, where Taylor series expansion of the displacement and rotation fields and the extended averaging procedure with an explicit enforcement of equilibrium are adopted in the micromechanical analysis of a unit cell.In numerical examples, the effective micropolar constants obtained in this paper and others derived in the literature are used for the equivalent micropolar continuum simulation of cellular solids. The solutions from the equivalent analysis are compared with the discrete simulation solutions of the cellular solids. It is found that the micropolar constants developed in this paper give satisfying results of equivalent analysis for the periodic cellular material.
