Periodic photonic structures can provide rich modulation in propagation of light due to well-defined band structures.Especially near band edges,light localization and the effect of near-zero refractive index have attr...Periodic photonic structures can provide rich modulation in propagation of light due to well-defined band structures.Especially near band edges,light localization and the effect of near-zero refractive index have attracted wide attention.However,the practically fabricated structures can only have finite size,i.e.,limited numbers of periods,leading to changes of the light propagation modulation compared with infinite structures.Here,we study the size effect on light localization and near-zero refractive-index propagation near band edges in one-dimensional periodic structures.Near edges of the band gap,as the structure's size shrinks,the broadening of the band gap and the weakening of the light localization are discovered.When the size is small,an added layer on the surface will perform large modulation in the group velocity.Near the degenerate point with Dirac-like dispersion,the zero-refractive-index effects like the zero-phase difference and near-unity transmittance retain as the size changes,while absolute group velocity fluctuates when the size shrinks.展开更多
By means of Muskhelishvili’s method and the technique of generalized conformal mapping,the physical plane problems are transformed into regular mathematical problems in quasicrystals(QCs).The analytical solution to a...By means of Muskhelishvili’s method and the technique of generalized conformal mapping,the physical plane problems are transformed into regular mathematical problems in quasicrystals(QCs).The analytical solution to an elliptical orifice problem with asymmetric cracks in one-dimensional(1D)orthorhombic QCs is obtained.By using the Dugdale-Barenblatt model,the plastic simulation at the crack tip of the elliptical orifice with asymmetric cracks in 1D orthorhombic QCs is performed.Finally,the size of the atomic cohesive force zone is determined precisely,and the size of the atomic cohesive force zone around the crack tip of an elliptical orifice with a single crack or two symmetric cracks is obtained.展开更多
In this paper,we investigate the interfacial behavior of a thin one-dimensional(1D)hexagonal quasicrystal(QC)film bonded on an elastic substrate subjected to a mismatch strain due to thermal variation.The contact inte...In this paper,we investigate the interfacial behavior of a thin one-dimensional(1D)hexagonal quasicrystal(QC)film bonded on an elastic substrate subjected to a mismatch strain due to thermal variation.The contact interface is assumed to be nonslipping,with both perfectly bonded and debonded boundary conditions.The Fourier transform technique is adopted to establish the integral equations in terms of interfacial shear stress,which are solved as a linear algebraic system by approximating the unknown phonon interfacial shear stress via the series expansion of the Chebyshev polynomials.The expressions are explicitly obtained for the phonon interfacial shear stress,internal normal stress,and stress intensity factors(SIFs).Finally,based on numerical calculations,we briefly discuss the effects of the material mismatch,the geometry of the QC film,and the debonded length and location on stresses and SIFs.展开更多
One-dimensional(1D)Pt-based electrocatalysts demonstrate outstanding catalytic activities and stability toward the oxygen reduction reaction(ORR).Advances in three-dimensional(3D)ordered electrodes based on 1D Pt-base...One-dimensional(1D)Pt-based electrocatalysts demonstrate outstanding catalytic activities and stability toward the oxygen reduction reaction(ORR).Advances in three-dimensional(3D)ordered electrodes based on 1D Pt-based nanostructure arrays have revealed great potential for developing highperformance proton exchange membrane fuel cells(PEMFCs),in particular for addressing the mass transfer and durability challenges of Pt/C nanoparticle electrodes.This paper reviews recent progress in the field,with a focus on the 3D ordered electrodes based on self-standing Pt nanowire arrays.Nanostructured thin-film(NSTF)catalysts are discussed along with electrodes made from Pt-based nanoparticles deposited on arrays of polymer nanowires,and carbon and TiO2 nanotubes.Achievements on electrodes from Pt-based nanotube arrays are also reviewed.The importance of size,surface properties,and the distribution control of 1D catalyst nanostructures is indicated.Finally,challenges and future development opportunities are addressed regarding increasing electrochemical surface area(ECSA)and quantifying oxygen mass transport resistance for 1D nanostructure array electrodes.展开更多
The density functional theory method is utilized to verify the electronic structures of SiC nanotubes(SiCNTs) and SiC nanoribbons(SiCNRs) one-dimensional(1D) van der Waals homojunctions(vdWh) under an applied axial st...The density functional theory method is utilized to verify the electronic structures of SiC nanotubes(SiCNTs) and SiC nanoribbons(SiCNRs) one-dimensional(1D) van der Waals homojunctions(vdWh) under an applied axial strain and an external electric field. According to the calculated results, the SiCNTs/SiCNRs 1D vdWhs are direct semiconductors with a type-II band alignment and robust electronic structures with different diameters or widths. Furthermore,the SiCNTs/SiCNRs 1D vdWhs are direct semiconductors with a type-I band alignment, respectively, in a range of[-0.3,-0.1] V/A and [0.1, 0.3] V/A and change into metal when the electric field intensity is equal to or higher than0.4 V/A. Interestingly, the SiCNTs/SiCNRs 1D vdWhs have robust electronic structures under axial strain. These findings demonstrate theoretically that the SiCNTs/SiCNRs 1D vdWhs can be employed in nanoelectronics devices.展开更多
This paper presents a strategy for computation of super-convergent solutions of multi-dimensional problems in the finite element method (FEM) by recursive application of the one-dimensional (1D) element energy pro...This paper presents a strategy for computation of super-convergent solutions of multi-dimensional problems in the finite element method (FEM) by recursive application of the one-dimensional (1D) element energy projection (EEP) technique. The main idea is to conceptually treat multi-dimensional problems as generalized 1D problems, based on which the concepts of generalized 1D FEM and its consequent EEP formulae have been developed in a unified manner. Equipped with these concepts, multi-dimensional problems can be recursively discretized in one dimension at each step, until a fully discretized standard finite element (FE) model is reached. This conceptual dimension-by- dimension (D-by-D) discretization procedure is entirely equivalent to a full FE discretization. As a reverse D-by-D recovery procedure, by using the unified EEP formulae together with proper extraction of the generalized nodal solutions, super-convergent displacements and first derivatives for two-dimensional (2D) and three-dimensional (3D) problems can be obtained over the domain. Numerical examples of 3D Poisson's equation and elasticity problem are given to verify the feasibility and effectiveness of the proposed strategy.展开更多
The semi-analytical solutions to Fredlund and Hasan's one-dimensional (1D) consolidation for unsaturated soils with a semi-permeable drainage boundary are pre- seated. Two variables are introduced to transform the ...The semi-analytical solutions to Fredlund and Hasan's one-dimensional (1D) consolidation for unsaturated soils with a semi-permeable drainage boundary are pre- seated. Two variables are introduced to transform the two coupled governing equations of pore-water and pore-air pressures into an equivalent set of partial differential equations (PDFs), which are easily solved by the Laplace transform method. Then, the pore-water pressure, pore-air pressure, and soil settlement are obtained in the Laplace domain. The Crump method is adopted to perform the inverse Laplace transform in order to obtain the semi-analytical solutions in the time domain. It is shown that the proposed solutions are more applicable to various types of boundary conditions and agree well with the existing solutions from the literature. Several numerical examples are provided to investigate the consolidation behavior of an unsaturated single-layer soil with single, double, mixed, and semi-permeable drainage boundaries. The changes in the pore-air and pore-water pres- sures and the soil settlement with the time factor at different values of the semi-permeable drainage boundary parameters are illustrated. In addition, parametric studies are con- ducted on the pore-air and pore-water pressures at different ratios (the air permeability coefficient to the water permeability coefficient) and depths.展开更多
Within the framework of continuum mechanics, the double power series ex- pansion technique is proposed, and a series of reduced one-dimensional (1D) equations for a piezoelectric semiconductor beam are obtained. The...Within the framework of continuum mechanics, the double power series ex- pansion technique is proposed, and a series of reduced one-dimensional (1D) equations for a piezoelectric semiconductor beam are obtained. These derived equations are universal, in which extension, flexure, and shear deformations are all included, and can be degen- erated to a number of special cases, e.g., extensional motion, coupled extensional and flexural motion with shear deformations, and elementary flexural motion without shear deformations. As a typical application, the extensional motion of a ZnO beam is analyzed sequentially. It is revealed that semi-conduction has a great effect on the performance of the piezoelectric semiconductor beam, including static deformations and dynamic be- haviors. A larger initial carrier density will evidently lead to a lower resonant frequency and a smaller displacement response, which is a little similar to the dissipative effect. Both the derived approximate equations and the corresponding qualitative analysis are general and widely applicable, which can clearly interpret the inner physical mechanism of the semiconductor in the piezoelectrics and provide theoretical guidance for further experimental design.展开更多
The explicit expression of Eshelby tensors for one-dimensional(1D) hexagonal quasicrystal composites is presented by using Green’s function method. The closed forms of Eshelby tensors in the special cases of spheroid...The explicit expression of Eshelby tensors for one-dimensional(1D) hexagonal quasicrystal composites is presented by using Green’s function method. The closed forms of Eshelby tensors in the special cases of spheroid, elliptic cylinder, ribbon-like,penny-shaped, and rod-shaped inclusions embedded in 1 D hexagonal quasicrystal matrices are given. As an application of Eshelby tensors, the analytical expressions for the effective properties of the 1 D hexagonal quasicrystal composites are derived based on the Mori-Tanaka method. The effects of the volume fraction of the inclusion on the elastic properties of the composite materials are discussed.展开更多
Grain crushing plays an important role in one-dimensional (1D) compression and creep behaviors of granular materials under high stress. It is clear that the macro-properties of granular materials are closely related t...Grain crushing plays an important role in one-dimensional (1D) compression and creep behaviors of granular materials under high stress. It is clear that the macro-properties of granular materials are closely related to the micro-fracture properties of grains in 1D compression and creep tests. In this paper, a series of 1D compression and creep tests were performed on Ottawa sand to investigate the deformation and grain crushing properties of granular materials, and it shows that the void ratio is correlated to the grain crushing amount (the quantity of crushed grains) for granular materials subjected to grain crushing. The test results, combining with the existing test data related to grain crushing of granular materials, were used to verify the relation. Moreover, the implications of these relations on the yield of granular material, and the equivalent effect of stress and time in changing soil fabric are presented.展开更多
Based on non-Darcian flow caused by non-Newtonian liquid, the theory of one-dimensional (1D) consolidation was modified to consider variation in the total vertical stress with depth and time. The finite difference met...Based on non-Darcian flow caused by non-Newtonian liquid, the theory of one-dimensional (1D) consolidation was modified to consider variation in the total vertical stress with depth and time. The finite difference method (FDM) was adopted to obtain numerical solutions for excess pore water pressure and average degree of consolidation. When non-Darcian flow is degenerated into Darcian flow, a comparison between numerical solutions and analytical solutions was made to verify reliability of finite difference solutions. Finally, taking into account the ramp time-dependent loading, consolidation behaviors with non-Darcian flow under various parameters were analyzed. Thus, a comprehensive analysis of 1D consolidation combined with non-Darcian flow caused by non-Newtonian liquid was conducted in this paper.展开更多
Piezoelectric semiconductors(PSs)possess both semiconducting properties and piezoelectric coupling effects,making them optimal building blocks for semiconductor devices.PS fiber-like structures have wide applications ...Piezoelectric semiconductors(PSs)possess both semiconducting properties and piezoelectric coupling effects,making them optimal building blocks for semiconductor devices.PS fiber-like structures have wide applications in multi-functional semiconductor devices.In this paper,a one-dimensional(1D)theoretical model is established to describe the piezotronic responses of a PS fiber under gradient temperature changes.The theoretical model aims to explain the mechanism behind the resistance change caused by such gradient temperature changes.Numerical results demonstrate that a gradient temperature change significantly affects the physical fields within the PS fiber,and can induce changes in its surface resistance.It provides important theoretical guidance on the development of piezotronic devices that are sensitive to temperature effects.展开更多
We address the existence of surface solitons at an interface in a defocusing cubic medium with an imprinted one-dimensional (1D) composite Bessel optical lattice. This setting is composed of two Bessel lattices with...We address the existence of surface solitons at an interface in a defocusing cubic medium with an imprinted one-dimensional (1D) composite Bessel optical lattice. This setting is composed of two Bessel lattices with different orders and different modulation depths, separated beside both sides of an interface. Stability analysis and numerical propagation simulations prove that solitons supported by the model are dynamically stable in the entire domain of their existence. The order of lattice determines the shape of soliton, and the amplitude of soliton depends on the lattice modulation depth. The experimental realization of the scheme is also proposed. Our results may provide another effective way of controlling the shapes of surface solitons and thus their evolutions by introducing a new freedom degree.展开更多
In this paper, the three-dimensional(3D) interfacial fracture is analyzed in a one-dimensional(1D) hexagonal quasicrystal(QC) coating structure under mechanical loading. A planar interface crack with arbitrary shape i...In this paper, the three-dimensional(3D) interfacial fracture is analyzed in a one-dimensional(1D) hexagonal quasicrystal(QC) coating structure under mechanical loading. A planar interface crack with arbitrary shape is studied by a displacement discontinuity method. Fundamental solutions of interfacial concentrated displacement discontinuities are obtained by the Hankel transform technique, and the corresponding boundary integral-differential equations are constructed with the superposition principle.Green’s functions of constant interfacial displacement discontinuities within a rectangular element are derived, and a boundary element method is proposed for numerical simulation.The singularity of stresses near the crack front is investigated, and the stress intensity factors(SIFs) as well as energy release rates(ERRs) are determined. Finally, relevant influencing factors on the fracture behavior are discussed.展开更多
Electrolytic water splitting by renewable energy is a technology with great potential for producing hydrogen(H_(2))without carbon emission,but this technical route is hindered by its huge energy(electricity)cost,which...Electrolytic water splitting by renewable energy is a technology with great potential for producing hydrogen(H_(2))without carbon emission,but this technical route is hindered by its huge energy(electricity)cost,which is mainly wasted by the anode oxygen evolution reaction(OER)while the value of the anode product(oxygen)is very limited.Replacing the high-energy-cost OER with a selective organic compound electrooxidation carried out at a relatively lower potential can reduce the electricity cost while producing value-added chemicals.Currently,H_(2) generation coupled with synthesis of value-added organic compounds faces the challenge of low selectivity and slow generation rate of the anodic products.One-dimensional(1D)nanocatalysts with a unique morphology,well-defined active sites,and good electron conductivity have shown excellent performance in many electrocatalytic reactions.The rational design and regulation of 1D nanocatalysts through surface engineering can optimize the adsorption energy of intermediate molecules and improve the selectivity of organic electrooxidation reactions.Herein,we summarized the recent research progress of 1D nanocatalysts applied in different organic electrooxidation reactions and introduced several different fabrication strategies for surface engineering of 1D nanocatalysts.Then,we focused on the relationship between surface engineering and the selectivity of organic electrooxidation reaction products.Finally,future challenges and development prospects of 1D nanocatalysts in the coupled system consisting of organic electrooxidation and hydrogen evolution reactions are briefly outlined.展开更多
Detecting light from a wealth of physical degrees of freedom(e.g.wavelength,intensity,polarization state,phase,etc)enables the acquirement of more comprehensive information.In the past two decades,low-dimensional van ...Detecting light from a wealth of physical degrees of freedom(e.g.wavelength,intensity,polarization state,phase,etc)enables the acquirement of more comprehensive information.In the past two decades,low-dimensional van der Waals materials(vdWMs)have established themselves as transformative building blocks toward lensless polarization optoelectronics,which is highly beneficial for optoelectronic system miniaturization.This review provides a comprehensive overview on the recent development of low-dimensional vdWM polarized photodetectors.To begin with,the exploitation of pristine 1D/2D vdWMs with immanent in-plane anisotropy and related heterostructures for filterless polarization-sensitive photodetectors is introduced.Then,we have systematically epitomized the various strategies to induce polarization photosensitivity and enhance the degree of anisotropy for low-dimensional vdWM photodetectors,including quantum tailoring,construction of core–shell structures,rolling engineering,ferroelectric regulation,strain engineering,etc,with emphasis on the fundamental physical principles.Following that,the ingenious optoelectronic applications based on the low-dimensional vdWM polarized photodetectors,including multiplexing optical communications and enhanced-contrast imaging,have been presented.In the end,the current challenges along with the future prospects of this burgeoning research field have been underscored.On the whole,the review depicts a fascinating landscape for the next-generation high-integration multifunctional optoelectronic systems.展开更多
Polycrystalline rock salt’s compression is a function of applied stresses,exposure duration to the applied stresses,ambient temperature,and water content.Rock salt’s compressional behavior under different conditions...Polycrystalline rock salt’s compression is a function of applied stresses,exposure duration to the applied stresses,ambient temperature,and water content.Rock salt’s compressional behavior under different conditions and its effects on the specimens’mechanical properties have been investigated in the literature.However,the one-dimensional(1D)compression behavior of polycrystalline rock salt at various water contents and how the specimen’s compression at different water contents further affects its physical and mechanical properties are not fully understood yet.In this study,polycrystalline rock salt specimens were prepared under nominally dry and wet conditions and some of the dry and wet specimens were annealed after the preparation.The relationship between the porosity of the specimens and the logarithm of the applied axial stresses during the 1D compression was found to follow a linear relationship after reaching unique critical porosities of 32%and 37%for the dry and wet specimens,respectively.Unloading and reloading the specimens did not result in any major changes in the porosity of the specimens.The specimens compressed under wet condition showed an average final porosity of 2.6%compared to 6.9%for the dry specimens.The dry and wet specimens that were annealed after the compression exhibited a lower porosity in comparison to the dry and wet specimens,respectively.Unconfined compression experiments on the specimens showed dry and wet specimens possess averaged unconfined compressive strengths(σ_(u))of 64.3 and 16.2 MPa,respectively.Annealing decreased σ_(u)of the dry specimens to 39.6 MPa and increased σ_(u)of the wet specimens to 41 MPa.展开更多
Studies on heat conduction are so far mainly focused on regular systems such as the one-dimensional(1D) and twodimensional(2D) lattices where atoms are regularly connected and temperatures of atoms are homogeneous...Studies on heat conduction are so far mainly focused on regular systems such as the one-dimensional(1D) and twodimensional(2D) lattices where atoms are regularly connected and temperatures of atoms are homogeneously distributed.However, realistic systems such as the nanotube/nanowire networks are not regular but heterogeneously structured, and their heat conduction remains largely unknown. We present a model of quasi-physical networks to study heat conduction in such physical networks and focus on how the network structure influences the heat conduction coefficient κ. In this model,we for the first time consider each link as a 1D chain of atoms instead of a spring in the previous studies. We find that κ is different from link to link in the network, in contrast to the same constant in a regular 1D or 2D lattice. Moreover, for each specific link, we present a formula to show how κ depends on both its link length and the temperatures on its two ends.These findings show that the heat conduction in physical networks is not a straightforward extension of 1D and 2D lattices but seriously influenced by the network structure.展开更多
There have been intensive and continuous research efforts in large-scale controlled assembly of one-dimensional(1D)nanomaterials,since this is the most effective and promising route toward advanced functional systems ...There have been intensive and continuous research efforts in large-scale controlled assembly of one-dimensional(1D)nanomaterials,since this is the most effective and promising route toward advanced functional systems including integrated nano-circuits and flexible electronic devices.To date,numerous assembly approaches have been reported,showing considerable progresses in developing a variety of 1D nanomaterial assemblies and integrated systems with outstanding performance.However,obstacles and challenges remain ahead.Here,in this review,we summarize most widely studied assembly approaches such as Langmuir-Blodgett technique,substrate release/stretching,substrate rubbing and blown bubble films,depending on three types of external forces:compressive,tensile and shear forces.We highlight the important roles of these mechanical forces in aligning 1D nanomaterials such as semiconducting nanowires and carbon nanotubes,and discuss each approach on their effectiveness in achieving high-degree alignment,distinct characteristics and major limitations.Finally,we point out possible research directions in this field including rational control on the orientation,density and registration,toward scale-up and cost-effective manufacturing,as well as novel assembled systems based on 1D heterojunctions and hybrid structures.展开更多
基金the National Key Basic Research Program of China(Grant No.2022YFA1404800)the National Natural Science Foundation of China(Grant Nos.12234007 and 12221004)supported by Science and Technology Commission of Shanghai Municipality,China(Grant Nos.19XD1434600,2019SHZDZX01,19DZ2253000,20501110500,and 21DZ1101500)。
文摘Periodic photonic structures can provide rich modulation in propagation of light due to well-defined band structures.Especially near band edges,light localization and the effect of near-zero refractive index have attracted wide attention.However,the practically fabricated structures can only have finite size,i.e.,limited numbers of periods,leading to changes of the light propagation modulation compared with infinite structures.Here,we study the size effect on light localization and near-zero refractive-index propagation near band edges in one-dimensional periodic structures.Near edges of the band gap,as the structure's size shrinks,the broadening of the band gap and the weakening of the light localization are discovered.When the size is small,an added layer on the surface will perform large modulation in the group velocity.Near the degenerate point with Dirac-like dispersion,the zero-refractive-index effects like the zero-phase difference and near-unity transmittance retain as the size changes,while absolute group velocity fluctuates when the size shrinks.
基金Project supported by the National Natural Science Foundation of China(Nos.12162027 and 11962026)the Natural Science Key Project of Science and Technology Research in Higher Education Institutions of Inner Mongolia Autonomous Region(No.NJZZ22574)。
文摘By means of Muskhelishvili’s method and the technique of generalized conformal mapping,the physical plane problems are transformed into regular mathematical problems in quasicrystals(QCs).The analytical solution to an elliptical orifice problem with asymmetric cracks in one-dimensional(1D)orthorhombic QCs is obtained.By using the Dugdale-Barenblatt model,the plastic simulation at the crack tip of the elliptical orifice with asymmetric cracks in 1D orthorhombic QCs is performed.Finally,the size of the atomic cohesive force zone is determined precisely,and the size of the atomic cohesive force zone around the crack tip of an elliptical orifice with a single crack or two symmetric cracks is obtained.
基金Project supported by the National Natural Science Foundation of China(Nos.11572289,1171407,11702252,and 11902293)the China Postdoctoral Science Foundation(No.2019M652563)。
文摘In this paper,we investigate the interfacial behavior of a thin one-dimensional(1D)hexagonal quasicrystal(QC)film bonded on an elastic substrate subjected to a mismatch strain due to thermal variation.The contact interface is assumed to be nonslipping,with both perfectly bonded and debonded boundary conditions.The Fourier transform technique is adopted to establish the integral equations in terms of interfacial shear stress,which are solved as a linear algebraic system by approximating the unknown phonon interfacial shear stress via the series expansion of the Chebyshev polynomials.The expressions are explicitly obtained for the phonon interfacial shear stress,internal normal stress,and stress intensity factors(SIFs).Finally,based on numerical calculations,we briefly discuss the effects of the material mismatch,the geometry of the QC film,and the debonded length and location on stresses and SIFs.
基金The author would like to acknowledge the support from the Engineering and Physical Sciences Research Council(EPSRC)(EP/L015749/1).
文摘One-dimensional(1D)Pt-based electrocatalysts demonstrate outstanding catalytic activities and stability toward the oxygen reduction reaction(ORR).Advances in three-dimensional(3D)ordered electrodes based on 1D Pt-based nanostructure arrays have revealed great potential for developing highperformance proton exchange membrane fuel cells(PEMFCs),in particular for addressing the mass transfer and durability challenges of Pt/C nanoparticle electrodes.This paper reviews recent progress in the field,with a focus on the 3D ordered electrodes based on self-standing Pt nanowire arrays.Nanostructured thin-film(NSTF)catalysts are discussed along with electrodes made from Pt-based nanoparticles deposited on arrays of polymer nanowires,and carbon and TiO2 nanotubes.Achievements on electrodes from Pt-based nanotube arrays are also reviewed.The importance of size,surface properties,and the distribution control of 1D catalyst nanostructures is indicated.Finally,challenges and future development opportunities are addressed regarding increasing electrochemical surface area(ECSA)and quantifying oxygen mass transport resistance for 1D nanostructure array electrodes.
基金Project supported by the National Natural Science Foundation of China(Grant No.11864011)the Youth Project of Scientific and Technological Research Program of Chongqing Education Commission,China(Grant Nos.KJQN202001207 and KJQN202101204)the Fund from the Educational Commission of Hubei Province,China(Grant No.T201914)。
文摘The density functional theory method is utilized to verify the electronic structures of SiC nanotubes(SiCNTs) and SiC nanoribbons(SiCNRs) one-dimensional(1D) van der Waals homojunctions(vdWh) under an applied axial strain and an external electric field. According to the calculated results, the SiCNTs/SiCNRs 1D vdWhs are direct semiconductors with a type-II band alignment and robust electronic structures with different diameters or widths. Furthermore,the SiCNTs/SiCNRs 1D vdWhs are direct semiconductors with a type-I band alignment, respectively, in a range of[-0.3,-0.1] V/A and [0.1, 0.3] V/A and change into metal when the electric field intensity is equal to or higher than0.4 V/A. Interestingly, the SiCNTs/SiCNRs 1D vdWhs have robust electronic structures under axial strain. These findings demonstrate theoretically that the SiCNTs/SiCNRs 1D vdWhs can be employed in nanoelectronics devices.
基金supported by the National Natural Science Foundation of China(Nos.51378293 and 51078199)
文摘This paper presents a strategy for computation of super-convergent solutions of multi-dimensional problems in the finite element method (FEM) by recursive application of the one-dimensional (1D) element energy projection (EEP) technique. The main idea is to conceptually treat multi-dimensional problems as generalized 1D problems, based on which the concepts of generalized 1D FEM and its consequent EEP formulae have been developed in a unified manner. Equipped with these concepts, multi-dimensional problems can be recursively discretized in one dimension at each step, until a fully discretized standard finite element (FE) model is reached. This conceptual dimension-by- dimension (D-by-D) discretization procedure is entirely equivalent to a full FE discretization. As a reverse D-by-D recovery procedure, by using the unified EEP formulae together with proper extraction of the generalized nodal solutions, super-convergent displacements and first derivatives for two-dimensional (2D) and three-dimensional (3D) problems can be obtained over the domain. Numerical examples of 3D Poisson's equation and elasticity problem are given to verify the feasibility and effectiveness of the proposed strategy.
基金Project supported by the National Natural Science Foundation of China(Nos.41630633 and11672172)
文摘The semi-analytical solutions to Fredlund and Hasan's one-dimensional (1D) consolidation for unsaturated soils with a semi-permeable drainage boundary are pre- seated. Two variables are introduced to transform the two coupled governing equations of pore-water and pore-air pressures into an equivalent set of partial differential equations (PDFs), which are easily solved by the Laplace transform method. Then, the pore-water pressure, pore-air pressure, and soil settlement are obtained in the Laplace domain. The Crump method is adopted to perform the inverse Laplace transform in order to obtain the semi-analytical solutions in the time domain. It is shown that the proposed solutions are more applicable to various types of boundary conditions and agree well with the existing solutions from the literature. Several numerical examples are provided to investigate the consolidation behavior of an unsaturated single-layer soil with single, double, mixed, and semi-permeable drainage boundaries. The changes in the pore-air and pore-water pres- sures and the soil settlement with the time factor at different values of the semi-permeable drainage boundary parameters are illustrated. In addition, parametric studies are con- ducted on the pore-air and pore-water pressures at different ratios (the air permeability coefficient to the water permeability coefficient) and depths.
基金Project supported by the National Natural Science Foundation of China(Nos.11672223,11402187,and 51178390)the China Postdoctoral Science Foundation(No.2014M560762)the Fundamental Research Funds for the Central Universities of China(No.xjj2015131)
文摘Within the framework of continuum mechanics, the double power series ex- pansion technique is proposed, and a series of reduced one-dimensional (1D) equations for a piezoelectric semiconductor beam are obtained. These derived equations are universal, in which extension, flexure, and shear deformations are all included, and can be degen- erated to a number of special cases, e.g., extensional motion, coupled extensional and flexural motion with shear deformations, and elementary flexural motion without shear deformations. As a typical application, the extensional motion of a ZnO beam is analyzed sequentially. It is revealed that semi-conduction has a great effect on the performance of the piezoelectric semiconductor beam, including static deformations and dynamic be- haviors. A larger initial carrier density will evidently lead to a lower resonant frequency and a smaller displacement response, which is a little similar to the dissipative effect. Both the derived approximate equations and the corresponding qualitative analysis are general and widely applicable, which can clearly interpret the inner physical mechanism of the semiconductor in the piezoelectrics and provide theoretical guidance for further experimental design.
基金the National Natural Science Foundation of China(Nos.11962026,12002175,12162027,and 62161045)the Inner Mongolia Natural Science Foundation of China(No.2020MS01018)。
文摘The explicit expression of Eshelby tensors for one-dimensional(1D) hexagonal quasicrystal composites is presented by using Green’s function method. The closed forms of Eshelby tensors in the special cases of spheroid, elliptic cylinder, ribbon-like,penny-shaped, and rod-shaped inclusions embedded in 1 D hexagonal quasicrystal matrices are given. As an application of Eshelby tensors, the analytical expressions for the effective properties of the 1 D hexagonal quasicrystal composites are derived based on the Mori-Tanaka method. The effects of the volume fraction of the inclusion on the elastic properties of the composite materials are discussed.
基金Supported by Natural Sciences and Engineering Research Council of Canada, Alberta Energy Research Institute and the Department of Civil Engineering at University of Calgary
文摘Grain crushing plays an important role in one-dimensional (1D) compression and creep behaviors of granular materials under high stress. It is clear that the macro-properties of granular materials are closely related to the micro-fracture properties of grains in 1D compression and creep tests. In this paper, a series of 1D compression and creep tests were performed on Ottawa sand to investigate the deformation and grain crushing properties of granular materials, and it shows that the void ratio is correlated to the grain crushing amount (the quantity of crushed grains) for granular materials subjected to grain crushing. The test results, combining with the existing test data related to grain crushing of granular materials, were used to verify the relation. Moreover, the implications of these relations on the yield of granular material, and the equivalent effect of stress and time in changing soil fabric are presented.
基金Supported by the National Natural Science Foundation of China (51109092,50878191)
文摘Based on non-Darcian flow caused by non-Newtonian liquid, the theory of one-dimensional (1D) consolidation was modified to consider variation in the total vertical stress with depth and time. The finite difference method (FDM) was adopted to obtain numerical solutions for excess pore water pressure and average degree of consolidation. When non-Darcian flow is degenerated into Darcian flow, a comparison between numerical solutions and analytical solutions was made to verify reliability of finite difference solutions. Finally, taking into account the ramp time-dependent loading, consolidation behaviors with non-Darcian flow under various parameters were analyzed. Thus, a comprehensive analysis of 1D consolidation combined with non-Darcian flow caused by non-Newtonian liquid was conducted in this paper.
基金Project supported by the National Natural Science Foundation of China (Nos.12172326 and 11972319)the National Key Research and Development Program of China (No.2020YFA0711700)the Natural Science Foundation of Zhejiang Province of China (No.LR21A020002)。
文摘Piezoelectric semiconductors(PSs)possess both semiconducting properties and piezoelectric coupling effects,making them optimal building blocks for semiconductor devices.PS fiber-like structures have wide applications in multi-functional semiconductor devices.In this paper,a one-dimensional(1D)theoretical model is established to describe the piezotronic responses of a PS fiber under gradient temperature changes.The theoretical model aims to explain the mechanism behind the resistance change caused by such gradient temperature changes.Numerical results demonstrate that a gradient temperature change significantly affects the physical fields within the PS fiber,and can induce changes in its surface resistance.It provides important theoretical guidance on the development of piezotronic devices that are sensitive to temperature effects.
基金Project supported by the National Natural Science Foundation of China(Grant No10704067)the Scientific Research Foundation of Education Bureau of Zhejiang Province of China(Grant No20060493)
文摘We address the existence of surface solitons at an interface in a defocusing cubic medium with an imprinted one-dimensional (1D) composite Bessel optical lattice. This setting is composed of two Bessel lattices with different orders and different modulation depths, separated beside both sides of an interface. Stability analysis and numerical propagation simulations prove that solitons supported by the model are dynamically stable in the entire domain of their existence. The order of lattice determines the shape of soliton, and the amplitude of soliton depends on the lattice modulation depth. The experimental realization of the scheme is also proposed. Our results may provide another effective way of controlling the shapes of surface solitons and thus their evolutions by introducing a new freedom degree.
基金Project supported by the National Natural Science Foundation of China (Nos. 11572289, 1171407,11702252, and 11902293)the China Postdoctoral Science Foundation (No. 2019M652563)。
文摘In this paper, the three-dimensional(3D) interfacial fracture is analyzed in a one-dimensional(1D) hexagonal quasicrystal(QC) coating structure under mechanical loading. A planar interface crack with arbitrary shape is studied by a displacement discontinuity method. Fundamental solutions of interfacial concentrated displacement discontinuities are obtained by the Hankel transform technique, and the corresponding boundary integral-differential equations are constructed with the superposition principle.Green’s functions of constant interfacial displacement discontinuities within a rectangular element are derived, and a boundary element method is proposed for numerical simulation.The singularity of stresses near the crack front is investigated, and the stress intensity factors(SIFs) as well as energy release rates(ERRs) are determined. Finally, relevant influencing factors on the fracture behavior are discussed.
文摘Electrolytic water splitting by renewable energy is a technology with great potential for producing hydrogen(H_(2))without carbon emission,but this technical route is hindered by its huge energy(electricity)cost,which is mainly wasted by the anode oxygen evolution reaction(OER)while the value of the anode product(oxygen)is very limited.Replacing the high-energy-cost OER with a selective organic compound electrooxidation carried out at a relatively lower potential can reduce the electricity cost while producing value-added chemicals.Currently,H_(2) generation coupled with synthesis of value-added organic compounds faces the challenge of low selectivity and slow generation rate of the anodic products.One-dimensional(1D)nanocatalysts with a unique morphology,well-defined active sites,and good electron conductivity have shown excellent performance in many electrocatalytic reactions.The rational design and regulation of 1D nanocatalysts through surface engineering can optimize the adsorption energy of intermediate molecules and improve the selectivity of organic electrooxidation reactions.Herein,we summarized the recent research progress of 1D nanocatalysts applied in different organic electrooxidation reactions and introduced several different fabrication strategies for surface engineering of 1D nanocatalysts.Then,we focused on the relationship between surface engineering and the selectivity of organic electrooxidation reaction products.Finally,future challenges and development prospects of 1D nanocatalysts in the coupled system consisting of organic electrooxidation and hydrogen evolution reactions are briefly outlined.
基金supported by the National Natural Science Foundation of China(Grant Nos.U2001215,52272175)the Natural Science Foundation of Guangdong Province(Grant Nos.2021A1515110403,2022A1515011487)+1 种基金the Science and Technology Projects in Guangzhou(Grant No.202201011232)the One-Hundred Talents Program of Sun Yat-sen University,and State Key Laboratory of Optoelectronic Materials and Technologies.
文摘Detecting light from a wealth of physical degrees of freedom(e.g.wavelength,intensity,polarization state,phase,etc)enables the acquirement of more comprehensive information.In the past two decades,low-dimensional van der Waals materials(vdWMs)have established themselves as transformative building blocks toward lensless polarization optoelectronics,which is highly beneficial for optoelectronic system miniaturization.This review provides a comprehensive overview on the recent development of low-dimensional vdWM polarized photodetectors.To begin with,the exploitation of pristine 1D/2D vdWMs with immanent in-plane anisotropy and related heterostructures for filterless polarization-sensitive photodetectors is introduced.Then,we have systematically epitomized the various strategies to induce polarization photosensitivity and enhance the degree of anisotropy for low-dimensional vdWM photodetectors,including quantum tailoring,construction of core–shell structures,rolling engineering,ferroelectric regulation,strain engineering,etc,with emphasis on the fundamental physical principles.Following that,the ingenious optoelectronic applications based on the low-dimensional vdWM polarized photodetectors,including multiplexing optical communications and enhanced-contrast imaging,have been presented.In the end,the current challenges along with the future prospects of this burgeoning research field have been underscored.On the whole,the review depicts a fascinating landscape for the next-generation high-integration multifunctional optoelectronic systems.
基金This material is based on work supported by the National Science Foundation under Grant No.CMMI-1641054.
文摘Polycrystalline rock salt’s compression is a function of applied stresses,exposure duration to the applied stresses,ambient temperature,and water content.Rock salt’s compressional behavior under different conditions and its effects on the specimens’mechanical properties have been investigated in the literature.However,the one-dimensional(1D)compression behavior of polycrystalline rock salt at various water contents and how the specimen’s compression at different water contents further affects its physical and mechanical properties are not fully understood yet.In this study,polycrystalline rock salt specimens were prepared under nominally dry and wet conditions and some of the dry and wet specimens were annealed after the preparation.The relationship between the porosity of the specimens and the logarithm of the applied axial stresses during the 1D compression was found to follow a linear relationship after reaching unique critical porosities of 32%and 37%for the dry and wet specimens,respectively.Unloading and reloading the specimens did not result in any major changes in the porosity of the specimens.The specimens compressed under wet condition showed an average final porosity of 2.6%compared to 6.9%for the dry specimens.The dry and wet specimens that were annealed after the compression exhibited a lower porosity in comparison to the dry and wet specimens,respectively.Unconfined compression experiments on the specimens showed dry and wet specimens possess averaged unconfined compressive strengths(σ_(u))of 64.3 and 16.2 MPa,respectively.Annealing decreased σ_(u)of the dry specimens to 39.6 MPa and increased σ_(u)of the wet specimens to 41 MPa.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11135001 and 11375066)the National Basic Research Program of China(Grant No.2013CB834100)
文摘Studies on heat conduction are so far mainly focused on regular systems such as the one-dimensional(1D) and twodimensional(2D) lattices where atoms are regularly connected and temperatures of atoms are homogeneously distributed.However, realistic systems such as the nanotube/nanowire networks are not regular but heterogeneously structured, and their heat conduction remains largely unknown. We present a model of quasi-physical networks to study heat conduction in such physical networks and focus on how the network structure influences the heat conduction coefficient κ. In this model,we for the first time consider each link as a 1D chain of atoms instead of a spring in the previous studies. We find that κ is different from link to link in the network, in contrast to the same constant in a regular 1D or 2D lattice. Moreover, for each specific link, we present a formula to show how κ depends on both its link length and the temperatures on its two ends.These findings show that the heat conduction in physical networks is not a straightforward extension of 1D and 2D lattices but seriously influenced by the network structure.
基金supported by the National Natural Science Foundation of China(No.51802063).Y.Y.S.thanks the National Natural Science Foundation of China(No.51872267),A.Y.C.acknowledges the National Key R&D Program of China(No.2016YFE0127300).
文摘There have been intensive and continuous research efforts in large-scale controlled assembly of one-dimensional(1D)nanomaterials,since this is the most effective and promising route toward advanced functional systems including integrated nano-circuits and flexible electronic devices.To date,numerous assembly approaches have been reported,showing considerable progresses in developing a variety of 1D nanomaterial assemblies and integrated systems with outstanding performance.However,obstacles and challenges remain ahead.Here,in this review,we summarize most widely studied assembly approaches such as Langmuir-Blodgett technique,substrate release/stretching,substrate rubbing and blown bubble films,depending on three types of external forces:compressive,tensile and shear forces.We highlight the important roles of these mechanical forces in aligning 1D nanomaterials such as semiconducting nanowires and carbon nanotubes,and discuss each approach on their effectiveness in achieving high-degree alignment,distinct characteristics and major limitations.Finally,we point out possible research directions in this field including rational control on the orientation,density and registration,toward scale-up and cost-effective manufacturing,as well as novel assembled systems based on 1D heterojunctions and hybrid structures.