Helicity-dependent photocurrent(HDPC)of the surface states in a high-quality topological insulator(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplate grown by chemical vapor deposition(CVD)is investigated.By investigating the angle...Helicity-dependent photocurrent(HDPC)of the surface states in a high-quality topological insulator(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplate grown by chemical vapor deposition(CVD)is investigated.By investigating the angle-dependent HDPC,it is found that the HDPC is mainly contributed by the circular photogalvanic effect(CPGE)current when the incident plane is perpendicular to the connection of the two contacts,whereas the circular photon drag effect(CPDE)dominates the HDPC when the incident plane is parallel to the connection of the two contacts.In addition,the CPGE of the(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplate is regulated by temperature,light power,excitation wavelength,the source–drain and ionic liquid top-gate voltages,and the regulation mechanisms are discussed.It is demonstrated that(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplates may provide a good platform for novel opto-spintronics devices.展开更多
This study investigates the size-dependent wave propagation behaviors under the thermoelectric loads of porous functionally graded piezoelectric(FGP) nanoplates deposited in a viscoelastic foundation.It is assumed tha...This study investigates the size-dependent wave propagation behaviors under the thermoelectric loads of porous functionally graded piezoelectric(FGP) nanoplates deposited in a viscoelastic foundation.It is assumed that(i) the material parameters of the nanoplates obey a power-law variation in thickness and(ii) the uniform porosity exists in the nanoplates.The combined effects of viscoelasticity and shear deformation are considered by using the Kelvin-Voigt viscoelastic model and the refined higher-order shear deformation theory.The scale effects of the nanoplates are captured by employing nonlocal strain gradient theory(NSGT).The motion equations are calculated in accordance with Hamilton’s principle.Finally,the dispersion characteristics of the nanoplates are numerically determined by using a harmonic solution.The results indicate that the nonlocal parameters(NLPs) and length scale parameters(LSPs) have exactly the opposite effects on the wave frequency.In addition,it is found that the effect of porosity volume fractions(PVFs) on the wave frequency depends on the gradient indices and damping coefficients.When these two values are small,the wave frequency increases with the volume fraction.By contrast,at larger gradient index and damping coefficient values,the wave frequency decreases as the volume fraction increases.展开更多
In this paper, the free vibration of magneto- electro-elastic (MEE) nanoplates is investigated based on the nonlocal theory and Kirchhoff plate theory. The MEE nanoplate is assumed as all edges simply supported rect...In this paper, the free vibration of magneto- electro-elastic (MEE) nanoplates is investigated based on the nonlocal theory and Kirchhoff plate theory. The MEE nanoplate is assumed as all edges simply supported rectan gular plate subjected to the biaxial force, external electric potential, external magnetic potential, and temperature rise. By using the Hamilton's principle, the governing equations and boundary conditions are derived and then solved analytically to obtain the natural frequencies of MEE nanoplates. A parametric study is presented to examine the effect of the nonlocal parameter, thermo-magneto-electro-mechanical loadings and aspect ratio on the vibration characteristics of MEE nanoplates. It is found that the natural frequency is quite sensitive to the mechanical loading, electric loading and magnetic loading, while it is insensitive to the thermal loading.展开更多
In this paper,we analytically study vibration of functionally graded piezoelectric(FGP)nanoplates based on the nonlocal strain gradient theory.The top and bottom surfaces of the nanoplate are made of PZT-5H and PZT-4,...In this paper,we analytically study vibration of functionally graded piezoelectric(FGP)nanoplates based on the nonlocal strain gradient theory.The top and bottom surfaces of the nanoplate are made of PZT-5H and PZT-4,respectively.We employ Hamilton’s principle and derive the governing differential equations.Then,we use Navier’s solution to obtain the natural frequencies of the FGP nanoplate.In the first step,we compare our results with the obtained results for the piezoelectric nanoplates in the previous studies.In the second step,we neglect the piezoelectric effect and compare our results with those obtained for the functionally graded(FG)nanoplates.Finally,the effects of the FG power index,the nonlocal parameter,the aspect ratio,and the lengthto-thickness ratio,and the nanoplate shape on natural frequencies are investigated.展开更多
A mathematical model for nonlocal vibration and buckling of embedded two-dimensional(2 D) decagonal quasicrystal(QC) layered nanoplates is proposed. The Pasternak-type foundation is used to simulate the interaction be...A mathematical model for nonlocal vibration and buckling of embedded two-dimensional(2 D) decagonal quasicrystal(QC) layered nanoplates is proposed. The Pasternak-type foundation is used to simulate the interaction between the nanoplates and the elastic medium. The exact solutions of the nonlocal vibration frequency and buckling critical load of the 2 D decagonal QC layered nanoplates are obtained by solving the eigensystem and using the propagator matrix method. The present three-dimensional(3 D) exact solution can predict correctly the nature frequencies and critical loads of the nanoplates as compared with previous thin-plate and medium-thick-plate theories.Numerical examples are provided to display the effects of the quasiperiodic direction,length-to-width ratio, thickness of the nanoplates, nonlocal parameter, stacking sequence,and medium elasticity on the vibration frequency and critical buckling load of the 2 D decagonal QC nanoplates. The results show that the effects of the quasiperiodic direction on the vibration frequency and critical buckling load depend on the length-to-width ratio of the nanoplates. The thickness of the nanoplate and the elasticity of the surrounding medium can be adjusted for optimal frequency and critical buckling load of the nanoplate.This feature is useful since the frequency and critical buckling load of the 2 D decagonal QCs as coating materials of plate structures can now be tuned as one desire.展开更多
SrMoO4 nanoplates were synthesized by a facile reverse microemulsion method at room temperature.Energy evolution of this in situ growth process was monitored by means of a microcalorimeter.A sharp exothermic peak for ...SrMoO4 nanoplates were synthesized by a facile reverse microemulsion method at room temperature.Energy evolution of this in situ growth process was monitored by means of a microcalorimeter.A sharp exothermic peak for the initial reaction and two discontinuous relatively weak exothermic peaks for the subsequent crystal growth emerged on the microcalorimetric heat flow curve.Based on the in situ thermokinetic data,the rate constants of the nucleation process and crystallization process at 298.15 K were calculated to be 4.078×10-3 and 5.033×10-4 s-1,respectively.The growth mechanism and energy evolution were investigated.展开更多
This paper attempts to investigate the buckling and post-buckling behaviors of piezoelectric nanoplate based on the nonlocal Mindlin plate model and yon Karman geometric nonlinearity. An external electric voltage and ...This paper attempts to investigate the buckling and post-buckling behaviors of piezoelectric nanoplate based on the nonlocal Mindlin plate model and yon Karman geometric nonlinearity. An external electric voltage and a uniform temperature rise are applied on the piezoelectric nanoplate. Both the uniaxial and biaxial mechanical compression forces will be considered in the buckling and post-buckling analysis. By substituting the energy functions into the equation of the minimum total potential energy principle, the governing equations are derived directly, and then discretized through the differential quadrature (DQ) method. The buckling and post-buckling responses of piezoelectric nanoplates are calculated by employing a direct iterative method under different boundary conditions. The numerical results are presented to show the influences of different factors including the nonlocal parameter, electric voltage, and temperature rise on the buckling and post-buckling responses.展开更多
In this study,the wave propagation properties of piezoelectric sandwich nanoplates deposited on an orthotropic viscoelastic foundation are analyzed by considering the surface effects(SEs).The nanoplates are composed o...In this study,the wave propagation properties of piezoelectric sandwich nanoplates deposited on an orthotropic viscoelastic foundation are analyzed by considering the surface effects(SEs).The nanoplates are composed of a composite layer reinforced by graphene and two piezoelectric surface layers.Utilizing the modified Halpin-Tsai model,the material parameters of composite layers are obtained.The displacement field is determined by the sinusoidal shear deformation theory(SSDT).The Euler-Lagrange equation is derived by employing Hamilton’s principle and the constitutive equations of piezoelectric layers considering the SEs.Subsequently,the nonlocal strain gradient theory(NSGT)is used to obtain the equations of motion.Next,the effects of scale parameters,graphene distribution,orthotropic viscoelastic foundation,and SEs on the propagation behavior are numerically examined.The results reveal that the wave frequency is a periodic function of the orthotropic angle.Furthermore,the wave frequency increases with the increase in the SEs.展开更多
Biosynthesis of gold nanostructures has drawn increasing concerns because of its green and sustainable synthetic process. However, biosynthesis of gold nanoplates is still a challenge because of the expensive source a...Biosynthesis of gold nanostructures has drawn increasing concerns because of its green and sustainable synthetic process. However, biosynthesis of gold nanoplates is still a challenge because of the expensive source and difficulties of controllable formation of morphology and size. Herein, one-pot biosynthesis of gold nanoplates is proposed, in which cheap yeast was extracted as a green precursor. The morphologies and sizes of the gold nanostructures can be controlled via varying the pH value of the biomedium. In acid condition, gold nanoplates with side length from 1300 ± 200 to 300 ± 100 nm and height from 18 to 15 nm were obtained by increasing the pH value. Whereas, in neutral or basic condition, only gold nanoflowers and nanoparticles were obtained. It was determined that organic molecules, such as succinic acid, lactic acid, malic acid, and glutathione, which are generated in metabolism process, played important role in the reduction of gold ions. Besides, it was found that the gold nanoplates exhibited plasmonic property with prominent dipole infrared resonance in near-infrared region, indicating their potential in surface plasmon-enhanced applications, such as bioimaging and photothermal therapy.展开更多
Based on the modified couple-stress theory,the three-dimensional(3D)bending deformation and vibration responses of simply-supported and multilayered twodimensional(2D)decagonal quasicrystal(QC)nanoplates are investiga...Based on the modified couple-stress theory,the three-dimensional(3D)bending deformation and vibration responses of simply-supported and multilayered twodimensional(2D)decagonal quasicrystal(QC)nanoplates are investigated.The surface loading is assumed to be applied on the top surface in the bending analysis,the tractionfree boundary conditions on both the top and bottom surfaces of the nanoplates are used in the free vibration analysis,and a harmonic concentrated point loading is applied on the top surfaces of the nanoplates in the harmonic response analysis.The general solutions of the extended displacement and traction vectors for the homogeneous QC nanoplates are derived by solving the eigenvalue problem reduced from the final governing equations of motion with the modified couple-stress effect.By utilizing the propagator matrix method,the analytical solutions of the displacements of bending deformation for the phonon and phason fields,the natural frequency of free vibration,and the displacements of the harmonic responses of the phonon and phason fields are obtained.Numerical examples are illustrated to show the effects of the quasiperiodic direction,the material length scale parameter,and the the stacking sequence of the nanoplates on the bending deformation and vibration responses of two sandwich nanoplates made of QC and crystal materials.展开更多
Based on the nonlocal theory and Mindlin plate theory,the governing equations(i.e.,a system of partial differential equations(PDEs)for bending problem)of magnetoelectroelastic(MEE)nanoplates resting on the Pasternak e...Based on the nonlocal theory and Mindlin plate theory,the governing equations(i.e.,a system of partial differential equations(PDEs)for bending problem)of magnetoelectroelastic(MEE)nanoplates resting on the Pasternak elastic foundation are first derived by the variational principle.The polynomial particular solutions corresponding to the established model are then obtained and further employed as basis functions with the method of particular solutions(MPS)to solve the governing equations numerically.It is confirmed that for the present bending model,the new solution strategy possesses more general applicability and superior flexibility in the selection of collocation points.The effects of different boundary conditions,applied loads,and geometrical shapes on the bending properties of MEE nanoplates are evaluated by using the developed method.Some important conclusions are drawn,which should be helpful for the design and applications of electromagnetic nanoplate structures.展开更多
We report a facile and reproducible approach toward rapid seedless synthesis of single crystalline gold nanoplates with edge length on the order of microns.The reaction is carried out by reducing gold ions with ascorb...We report a facile and reproducible approach toward rapid seedless synthesis of single crystalline gold nanoplates with edge length on the order of microns.The reaction is carried out by reducing gold ions with ascorbic acid in the presence of cetyltrimethylammonium bromide(CTAB).Reaction temperature and molar ratio of CTAB/Au are critical for the formation of gold nanoplates in a high yield,which are,respectively,optimized to be 85 °C and 6.The highest yield that can be achieved is 60 % at the optimized condition.The synthesis to achieve the microscaled gold nanoplates can be finished in less than 1 h under proper reaction conditions.Therefore,the reported synthesis approach is a time-and costeffective one.The gold nanoplates were further employed as the surface-enhanced Raman scattering substrates and investigated individually.Interestingly,only those adsorbed with gold nanoparticles exhibit pronounced Raman signals of probe molecules,where a maximum enhancement factor of 1.7 9 10~7 was obtained.The obtained Raman enhancement can be ascribed to the plasmon coupling between the gold nanoplate and the nanoparticle adsorbed onto it.展开更多
On account of the high theoretical capacity, high corrosion resistance, environmental benignity, abundant availability and low cost, the research on a-Fe_2O_3 has been gradually fastened on as promising anodes materia...On account of the high theoretical capacity, high corrosion resistance, environmental benignity, abundant availability and low cost, the research on a-Fe_2O_3 has been gradually fastened on as promising anodes materials toward lithium-ion batteries(LIBs). A high-performance anode for LIBs based on α-Fe_2O_3 nanoplates have been selectively prepared. The α-Fe_2O_3 nanoplates can be synthesized with iron ionbased ionic liquid as iron source and template. The α-Fe_2O_3 nanoplates as the anode of LIBs can display high capacity of around1950 mAh g^(-1) at 0.5 A g^(-1) which have exceeded the theoretical capacity of α-Fe_2O_3. On account of unique nanoplate structures and gum arabic as binder, the α-Fe_2O_3 nanoplates also exhibit high rate capability and excellent cycling performance.展开更多
This paper presents a theoretical model for the size-dependent band structure of magneto-elastic phononic crystal(PC)nanoplates according to the Kirchhoff plate theory and Gurtin-Murdoch theory,in which the surface ef...This paper presents a theoretical model for the size-dependent band structure of magneto-elastic phononic crystal(PC)nanoplates according to the Kirchhoff plate theory and Gurtin-Murdoch theory,in which the surface effect and magneto-elastic coupling are considered.By introducing the nonlinear coupling constitutive relation of magnetostrictive materials,Terfenol-D/epoxy PC nanoplates are carried out as an example to investigate the dependence of the band structure on the surface effect,magnetic field,pre-stress,and geometric parameters.The results show that the surface effect has promotive influence on dispersion curves of the band structure,and the band gaps can be improved gradually with the increase in the material intrinsic length.Meanwhile,the band gaps exhibit obvious nonlinear coupling characteristics owing to the competition between the magnetic field and the pre-stress.By considering the surface effect and magneto-elastic coupling,the open and closed points of band gaps are found when the lattice constant to thickness ratio increases.The study may provide a method for flexible tunability of elastic wave propagation in magneto-elastic PC nanoplates and functional design of highperformance nanoplate-based devices.展开更多
Electromechanical property of a p-type single-crystal silicon nanoplate is modelled by a microscopic approach where the hole quantization effect and the spin-orbit coupling effect are taken into account. The visible a...Electromechanical property of a p-type single-crystal silicon nanoplate is modelled by a microscopic approach where the hole quantization effect and the spin-orbit coupling effect are taken into account. The visible anisotropic subband structures are calculated by solving self-consistently the stress-dependent 6×6 k.p Schrodinger equation with the Poisson equation. The strong mixing among heavy, light, and split-off holes is quantitatively assessed. The influences of the thickness and the temperature on the piezoresistive coefficient are quantitatively investigated by using the hole concentrations and the effective masses from the complex dispersion structure of the valence band with and without stresses. Our results show that the stress determines the extent to which the band is mixed. The hole quantization effect increases as the thickness decreases, and therefore the valence band is strongly reshaped, resulting in the size-dependent piezoresistivity of the silicon nanoplate. The piezoresistive coefficient increases almost 4 times as the thickness reduces from the bulk to 3 nm, exhibiting a promising application in mechanical sensors.展开更多
This paper is concerned with a buckling analysis of an embedded nanoplate integrated with magnetoelectroelastic(MEE) layers based on a nonlocal magnetoelectroelasticity theory. A surrounding elastic medium is simulate...This paper is concerned with a buckling analysis of an embedded nanoplate integrated with magnetoelectroelastic(MEE) layers based on a nonlocal magnetoelectroelasticity theory. A surrounding elastic medium is simulated by the Pasternak foundation that considers both shear and normal loads. The sandwich nanoplate(SNP) consists of a core that is made of metal and two MEE layers on the upper and lower surfaces of the core made of Ba Ti O3/Co Fe2 O4. The refined zigzag theory(RZT) is used to model the SNP subject to both external electric and magnetic potentials. Using an energy method and Hamilton’s principle, the governing motion equations are obtained, and then solved analytically. A detailed parametric study is conducted, concentrating on the combined effects of the small scale parameter, external electric and magnetic loads, thicknesses of MEE layers, mode numbers, and surrounding elastic medium. It is concluded that increasing the small scale parameter decreases the critical buckling loads.展开更多
To accelerate the kinetics of oxygen evolution reaction(OER)regarding the energy conversion and storage approaches,the discovery of desirable cost-effective and highly efficient electrocatalysts is of prime importance...To accelerate the kinetics of oxygen evolution reaction(OER)regarding the energy conversion and storage approaches,the discovery of desirable cost-effective and highly efficient electrocatalysts is of prime importance.This study demonstrates a layered CaCo_2O_4with a two-dimensional nanoplate structure,which possesses electrocatalytic activity for OER.The OER activity was achieved on CaCo_2O_4with a Tafel slope of 71 mV dec^(-1)and a current density of 10 mA cm^(-2)at an overpotential of 371 mV,which was more active than the similar structure LiCoO_2catalyst.Combined with X-ray absorption fine structure and density functional theory calculations,the enhanced OER activity and stability are mainly attributed to the unique electronic structure derived from the interaction of Ca and Co,and improved electrical conductivity.CaCo_2O_4can be developed as a highly active and earth-abundant catalyst for OER in energy conversion and storage technologies.展开更多
The driven self-assembly behaviors of hard nanoplates on soft elastic shells are investigated by using molecular dynamics (MD) simulation method, and the driven self-assembly structures of adsorbed hard nanoplates d...The driven self-assembly behaviors of hard nanoplates on soft elastic shells are investigated by using molecular dynamics (MD) simulation method, and the driven self-assembly structures of adsorbed hard nanoplates depend on the shape of hard nanoplates and the bending energy of soft elastic shells. Three main structures for adsorbed hard nanoplates, including the ordered aggregation structures of hard nanoplates for elastic shells with a moderate bending energy, the collapsed structures for elastic shells with a low bending energy, and the disordered aggregation structures for hard shells, are observed. The self-assembly process of adsorbed hard nanoplates is driven by the surface tension of the elastic shell, and the shape of driven self-assembly structures is determined on the basis of the minimization of the second moment of mass distribution. Meanwhile, the deformations of elastic shells can be controlled by the number of adsorbed rods as well as the length of adsorbed rods. This investigation can help us understand the complexity of the driven self-assembly of hard nanoplates on elastic shells.展开更多
In this paper,to better reveal the surface effect and the screening effect as well as the nonlinear multi-field coupling characteristic of the multifunctional piezoelectric semiconductor(PS)nanodevice,and to further i...In this paper,to better reveal the surface effect and the screening effect as well as the nonlinear multi-field coupling characteristic of the multifunctional piezoelectric semiconductor(PS)nanodevice,and to further improve its working performance,a magneto-mechanical-thermo coupling theoretical model is theoretically established for the extensional analysis of a three-layered magneto-electro-semiconductor coupling laminated nanoplate with the surface effect.Next,by using the current theoretical model,some numerical analyses and discussion about the surface effect,the corresponding critical thickness of the nanoplate,and the distributions of the physical fields(including the electron concentration perturbation,the electric potential,the electric field,the average electric displacement,the effective polarization charge density,and the total charge density)under different initial state electron concentrations,as well as their active manipulation via some external magnetic field,pre-stress,and temperature stimuli,are performed.Utilizing the nonlinear multi-field coupling effect induced by inevitable external stimuli in the device operating environment,this paper not only provides theoretical support for understanding the size-dependent tuning/controlling of carrier transport as well as its screening effect,but also assists the design of a series of multiferroic PS nanodevices.展开更多
β-Co(OH)2 and Mg(OH)2 nanoplates were synthesized via a facile template-free hydrothermal approach.The different conditions of preparation and catalytic properties of the products were studied and discussed.The p...β-Co(OH)2 and Mg(OH)2 nanoplates were synthesized via a facile template-free hydrothermal approach.The different conditions of preparation and catalytic properties of the products were studied and discussed.The products were characterized by X-ray diffraction,transmission electron microscopy,scanning electron microscopy,selected area electron diffraction(SAED),and gas chromatograph.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62074036,61674038,and 11574302)the Foreign Cooperation Project of Fujian Province,China(Grant No.2023I0005)+2 种基金the Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics(Grant No.KF202108)the National Key Research and Development Program of China(Grant No.2016YFB0402303)the Foundation of Fujian Provincial Department of Industry and Information Technology of China(Grant No.82318075)。
文摘Helicity-dependent photocurrent(HDPC)of the surface states in a high-quality topological insulator(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplate grown by chemical vapor deposition(CVD)is investigated.By investigating the angle-dependent HDPC,it is found that the HDPC is mainly contributed by the circular photogalvanic effect(CPGE)current when the incident plane is perpendicular to the connection of the two contacts,whereas the circular photon drag effect(CPDE)dominates the HDPC when the incident plane is parallel to the connection of the two contacts.In addition,the CPGE of the(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplate is regulated by temperature,light power,excitation wavelength,the source–drain and ionic liquid top-gate voltages,and the regulation mechanisms are discussed.It is demonstrated that(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplates may provide a good platform for novel opto-spintronics devices.
基金Project supported by the National Natural Science Foundation of China(Nos.11502218 and 11672252)。
文摘This study investigates the size-dependent wave propagation behaviors under the thermoelectric loads of porous functionally graded piezoelectric(FGP) nanoplates deposited in a viscoelastic foundation.It is assumed that(i) the material parameters of the nanoplates obey a power-law variation in thickness and(ii) the uniform porosity exists in the nanoplates.The combined effects of viscoelasticity and shear deformation are considered by using the Kelvin-Voigt viscoelastic model and the refined higher-order shear deformation theory.The scale effects of the nanoplates are captured by employing nonlocal strain gradient theory(NSGT).The motion equations are calculated in accordance with Hamilton’s principle.Finally,the dispersion characteristics of the nanoplates are numerically determined by using a harmonic solution.The results indicate that the nonlocal parameters(NLPs) and length scale parameters(LSPs) have exactly the opposite effects on the wave frequency.In addition,it is found that the effect of porosity volume fractions(PVFs) on the wave frequency depends on the gradient indices and damping coefficients.When these two values are small,the wave frequency increases with the volume fraction.By contrast,at larger gradient index and damping coefficient values,the wave frequency decreases as the volume fraction increases.
基金supported by the Australian Research Council (DP130104358)Fundamental Research Funds for the Central Universities under Grant number 2013JBM009+1 种基金Program for New Century Excellent Talents in University under Grant number NCET-13-0656Beijing Higher Education Young Elite Teacher Project under Grant number YETP0562
文摘In this paper, the free vibration of magneto- electro-elastic (MEE) nanoplates is investigated based on the nonlocal theory and Kirchhoff plate theory. The MEE nanoplate is assumed as all edges simply supported rectan gular plate subjected to the biaxial force, external electric potential, external magnetic potential, and temperature rise. By using the Hamilton's principle, the governing equations and boundary conditions are derived and then solved analytically to obtain the natural frequencies of MEE nanoplates. A parametric study is presented to examine the effect of the nonlocal parameter, thermo-magneto-electro-mechanical loadings and aspect ratio on the vibration characteristics of MEE nanoplates. It is found that the natural frequency is quite sensitive to the mechanical loading, electric loading and magnetic loading, while it is insensitive to the thermal loading.
文摘In this paper,we analytically study vibration of functionally graded piezoelectric(FGP)nanoplates based on the nonlocal strain gradient theory.The top and bottom surfaces of the nanoplate are made of PZT-5H and PZT-4,respectively.We employ Hamilton’s principle and derive the governing differential equations.Then,we use Navier’s solution to obtain the natural frequencies of the FGP nanoplate.In the first step,we compare our results with the obtained results for the piezoelectric nanoplates in the previous studies.In the second step,we neglect the piezoelectric effect and compare our results with those obtained for the functionally graded(FG)nanoplates.Finally,the effects of the FG power index,the nonlocal parameter,the aspect ratio,and the lengthto-thickness ratio,and the nanoplate shape on natural frequencies are investigated.
基金the National Natural Science Foundation of China(Nos.12072166 and 11862021)the Program for Science and Technology of Inner Mongolia Autonomous Region of China(No.2021GG0254)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(No.2020MS01006)。
文摘A mathematical model for nonlocal vibration and buckling of embedded two-dimensional(2 D) decagonal quasicrystal(QC) layered nanoplates is proposed. The Pasternak-type foundation is used to simulate the interaction between the nanoplates and the elastic medium. The exact solutions of the nonlocal vibration frequency and buckling critical load of the 2 D decagonal QC layered nanoplates are obtained by solving the eigensystem and using the propagator matrix method. The present three-dimensional(3 D) exact solution can predict correctly the nature frequencies and critical loads of the nanoplates as compared with previous thin-plate and medium-thick-plate theories.Numerical examples are provided to display the effects of the quasiperiodic direction,length-to-width ratio, thickness of the nanoplates, nonlocal parameter, stacking sequence,and medium elasticity on the vibration frequency and critical buckling load of the 2 D decagonal QC nanoplates. The results show that the effects of the quasiperiodic direction on the vibration frequency and critical buckling load depend on the length-to-width ratio of the nanoplates. The thickness of the nanoplate and the elasticity of the surrounding medium can be adjusted for optimal frequency and critical buckling load of the nanoplate.This feature is useful since the frequency and critical buckling load of the 2 D decagonal QCs as coating materials of plate structures can now be tuned as one desire.
基金Supported by the National Natural Science Foundation of China(No.20963001)the Major Project of Natural Science Foundation of Guangxi Province,China(No.0991001Z)
文摘SrMoO4 nanoplates were synthesized by a facile reverse microemulsion method at room temperature.Energy evolution of this in situ growth process was monitored by means of a microcalorimeter.A sharp exothermic peak for the initial reaction and two discontinuous relatively weak exothermic peaks for the subsequent crystal growth emerged on the microcalorimetric heat flow curve.Based on the in situ thermokinetic data,the rate constants of the nucleation process and crystallization process at 298.15 K were calculated to be 4.078×10-3 and 5.033×10-4 s-1,respectively.The growth mechanism and energy evolution were investigated.
基金supported by the National Natural Science Foundation of China (11272040 and 11322218)
文摘This paper attempts to investigate the buckling and post-buckling behaviors of piezoelectric nanoplate based on the nonlocal Mindlin plate model and yon Karman geometric nonlinearity. An external electric voltage and a uniform temperature rise are applied on the piezoelectric nanoplate. Both the uniaxial and biaxial mechanical compression forces will be considered in the buckling and post-buckling analysis. By substituting the energy functions into the equation of the minimum total potential energy principle, the governing equations are derived directly, and then discretized through the differential quadrature (DQ) method. The buckling and post-buckling responses of piezoelectric nanoplates are calculated by employing a direct iterative method under different boundary conditions. The numerical results are presented to show the influences of different factors including the nonlocal parameter, electric voltage, and temperature rise on the buckling and post-buckling responses.
基金supported by the National Natural Science Foundation of China(Nos.11502218,11672252,11602204,and 12102373)the Fundamental Research Funds for the Central Universities of China(No.2682020ZT106)。
文摘In this study,the wave propagation properties of piezoelectric sandwich nanoplates deposited on an orthotropic viscoelastic foundation are analyzed by considering the surface effects(SEs).The nanoplates are composed of a composite layer reinforced by graphene and two piezoelectric surface layers.Utilizing the modified Halpin-Tsai model,the material parameters of composite layers are obtained.The displacement field is determined by the sinusoidal shear deformation theory(SSDT).The Euler-Lagrange equation is derived by employing Hamilton’s principle and the constitutive equations of piezoelectric layers considering the SEs.Subsequently,the nonlocal strain gradient theory(NSGT)is used to obtain the equations of motion.Next,the effects of scale parameters,graphene distribution,orthotropic viscoelastic foundation,and SEs on the propagation behavior are numerically examined.The results reveal that the wave frequency is a periodic function of the orthotropic angle.Furthermore,the wave frequency increases with the increase in the SEs.
基金supported by the National Key Research and Development Program of China(2016YFC0102700)National Natural Science Foundation of China(21171117,21271181,21473240,and 81270209)+1 种基金Medical-Engineering Crossover Fund of Shanghai Jiao Tong University(YG2015MS51 and YG2014MS66)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning
文摘Biosynthesis of gold nanostructures has drawn increasing concerns because of its green and sustainable synthetic process. However, biosynthesis of gold nanoplates is still a challenge because of the expensive source and difficulties of controllable formation of morphology and size. Herein, one-pot biosynthesis of gold nanoplates is proposed, in which cheap yeast was extracted as a green precursor. The morphologies and sizes of the gold nanostructures can be controlled via varying the pH value of the biomedium. In acid condition, gold nanoplates with side length from 1300 ± 200 to 300 ± 100 nm and height from 18 to 15 nm were obtained by increasing the pH value. Whereas, in neutral or basic condition, only gold nanoflowers and nanoparticles were obtained. It was determined that organic molecules, such as succinic acid, lactic acid, malic acid, and glutathione, which are generated in metabolism process, played important role in the reduction of gold ions. Besides, it was found that the gold nanoplates exhibited plasmonic property with prominent dipole infrared resonance in near-infrared region, indicating their potential in surface plasmon-enhanced applications, such as bioimaging and photothermal therapy.
基金Project supported by the National Natural Science Foundation of China(Nos.11862021 and 12072166)the Program for Science and Technology of Inner Mongolia Autonomous Region of China(No.2021GG0254)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(No.2020MS01006)
文摘Based on the modified couple-stress theory,the three-dimensional(3D)bending deformation and vibration responses of simply-supported and multilayered twodimensional(2D)decagonal quasicrystal(QC)nanoplates are investigated.The surface loading is assumed to be applied on the top surface in the bending analysis,the tractionfree boundary conditions on both the top and bottom surfaces of the nanoplates are used in the free vibration analysis,and a harmonic concentrated point loading is applied on the top surfaces of the nanoplates in the harmonic response analysis.The general solutions of the extended displacement and traction vectors for the homogeneous QC nanoplates are derived by solving the eigenvalue problem reduced from the final governing equations of motion with the modified couple-stress effect.By utilizing the propagator matrix method,the analytical solutions of the displacements of bending deformation for the phonon and phason fields,the natural frequency of free vibration,and the displacements of the harmonic responses of the phonon and phason fields are obtained.Numerical examples are illustrated to show the effects of the quasiperiodic direction,the material length scale parameter,and the the stacking sequence of the nanoplates on the bending deformation and vibration responses of two sandwich nanoplates made of QC and crystal materials.
基金Project supported by the National Natural Science Foundation of China(Nos.11872257 and 11572358)the German Research Foundation(No.ZH 15/14-1)。
文摘Based on the nonlocal theory and Mindlin plate theory,the governing equations(i.e.,a system of partial differential equations(PDEs)for bending problem)of magnetoelectroelastic(MEE)nanoplates resting on the Pasternak elastic foundation are first derived by the variational principle.The polynomial particular solutions corresponding to the established model are then obtained and further employed as basis functions with the method of particular solutions(MPS)to solve the governing equations numerically.It is confirmed that for the present bending model,the new solution strategy possesses more general applicability and superior flexibility in the selection of collocation points.The effects of different boundary conditions,applied loads,and geometrical shapes on the bending properties of MEE nanoplates are evaluated by using the developed method.Some important conclusions are drawn,which should be helpful for the design and applications of electromagnetic nanoplate structures.
基金supported by the National Natural Science Foundation of China(NSFC)(Grants 21271181 and 21473240)Ministry of Science and Technology of China(Intergovernmental S&T Cooperation Project,Grant No.6–10)the Thousand Youth Talents Program of China
文摘We report a facile and reproducible approach toward rapid seedless synthesis of single crystalline gold nanoplates with edge length on the order of microns.The reaction is carried out by reducing gold ions with ascorbic acid in the presence of cetyltrimethylammonium bromide(CTAB).Reaction temperature and molar ratio of CTAB/Au are critical for the formation of gold nanoplates in a high yield,which are,respectively,optimized to be 85 °C and 6.The highest yield that can be achieved is 60 % at the optimized condition.The synthesis to achieve the microscaled gold nanoplates can be finished in less than 1 h under proper reaction conditions.Therefore,the reported synthesis approach is a time-and costeffective one.The gold nanoplates were further employed as the surface-enhanced Raman scattering substrates and investigated individually.Interestingly,only those adsorbed with gold nanoparticles exhibit pronounced Raman signals of probe molecules,where a maximum enhancement factor of 1.7 9 10~7 was obtained.The obtained Raman enhancement can be ascribed to the plasmon coupling between the gold nanoplate and the nanoparticle adsorbed onto it.
基金financially supported by the National Natural Science Foundation of China (No.21506081,21506077)Jiangsu University Scientific Research Funding (15JDG048)+1 种基金Chinese Postdoctoral Foundation (2016M590420)Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘On account of the high theoretical capacity, high corrosion resistance, environmental benignity, abundant availability and low cost, the research on a-Fe_2O_3 has been gradually fastened on as promising anodes materials toward lithium-ion batteries(LIBs). A high-performance anode for LIBs based on α-Fe_2O_3 nanoplates have been selectively prepared. The α-Fe_2O_3 nanoplates can be synthesized with iron ionbased ionic liquid as iron source and template. The α-Fe_2O_3 nanoplates as the anode of LIBs can display high capacity of around1950 mAh g^(-1) at 0.5 A g^(-1) which have exceeded the theoretical capacity of α-Fe_2O_3. On account of unique nanoplate structures and gum arabic as binder, the α-Fe_2O_3 nanoplates also exhibit high rate capability and excellent cycling performance.
基金Project supported by the National Natural Science Foundation of China(No.12002179)the Ningxia Key Research and Development Program(Special Talents)(No.2020BEB04001)the Natural Science Foundation of Ningxia of China(No.2021AAC03037)。
文摘This paper presents a theoretical model for the size-dependent band structure of magneto-elastic phononic crystal(PC)nanoplates according to the Kirchhoff plate theory and Gurtin-Murdoch theory,in which the surface effect and magneto-elastic coupling are considered.By introducing the nonlinear coupling constitutive relation of magnetostrictive materials,Terfenol-D/epoxy PC nanoplates are carried out as an example to investigate the dependence of the band structure on the surface effect,magnetic field,pre-stress,and geometric parameters.The results show that the surface effect has promotive influence on dispersion curves of the band structure,and the band gaps can be improved gradually with the increase in the material intrinsic length.Meanwhile,the band gaps exhibit obvious nonlinear coupling characteristics owing to the competition between the magnetic field and the pre-stress.By considering the surface effect and magneto-elastic coupling,the open and closed points of band gaps are found when the lattice constant to thickness ratio increases.The study may provide a method for flexible tunability of elastic wave propagation in magneto-elastic PC nanoplates and functional design of highperformance nanoplate-based devices.
基金Project supported by the National Basic Research Program of China (Grant No 2006CB300404)the National High-Technology Research and Development Program of China (Grant No 2007AA04Z301)
文摘Electromechanical property of a p-type single-crystal silicon nanoplate is modelled by a microscopic approach where the hole quantization effect and the spin-orbit coupling effect are taken into account. The visible anisotropic subband structures are calculated by solving self-consistently the stress-dependent 6×6 k.p Schrodinger equation with the Poisson equation. The strong mixing among heavy, light, and split-off holes is quantitatively assessed. The influences of the thickness and the temperature on the piezoresistive coefficient are quantitatively investigated by using the hole concentrations and the effective masses from the complex dispersion structure of the valence band with and without stresses. Our results show that the stress determines the extent to which the band is mixed. The hole quantization effect increases as the thickness decreases, and therefore the valence band is strongly reshaped, resulting in the size-dependent piezoresistivity of the silicon nanoplate. The piezoresistive coefficient increases almost 4 times as the thickness reduces from the bulk to 3 nm, exhibiting a promising application in mechanical sensors.
基金Project supported by the University of Kashan(No.574600/33)
文摘This paper is concerned with a buckling analysis of an embedded nanoplate integrated with magnetoelectroelastic(MEE) layers based on a nonlocal magnetoelectroelasticity theory. A surrounding elastic medium is simulated by the Pasternak foundation that considers both shear and normal loads. The sandwich nanoplate(SNP) consists of a core that is made of metal and two MEE layers on the upper and lower surfaces of the core made of Ba Ti O3/Co Fe2 O4. The refined zigzag theory(RZT) is used to model the SNP subject to both external electric and magnetic potentials. Using an energy method and Hamilton’s principle, the governing motion equations are obtained, and then solved analytically. A detailed parametric study is conducted, concentrating on the combined effects of the small scale parameter, external electric and magnetic loads, thicknesses of MEE layers, mode numbers, and surrounding elastic medium. It is concluded that increasing the small scale parameter decreases the critical buckling loads.
基金supported by the "Strategic Priority Research Program" of the Chinese Academy of Sciences (XDA02040600)supported by the Canadian Foundation for Innovation+5 种基金Natural Sciences and Engineering Research Council of Canadathe University of Saskatchewanthe Government of SaskatchewanWestern Economic Diversification Canadathe National Research Council Canadathe Canadian Institutes of Health Research
文摘To accelerate the kinetics of oxygen evolution reaction(OER)regarding the energy conversion and storage approaches,the discovery of desirable cost-effective and highly efficient electrocatalysts is of prime importance.This study demonstrates a layered CaCo_2O_4with a two-dimensional nanoplate structure,which possesses electrocatalytic activity for OER.The OER activity was achieved on CaCo_2O_4with a Tafel slope of 71 mV dec^(-1)and a current density of 10 mA cm^(-2)at an overpotential of 371 mV,which was more active than the similar structure LiCoO_2catalyst.Combined with X-ray absorption fine structure and density functional theory calculations,the enhanced OER activity and stability are mainly attributed to the unique electronic structure derived from the interaction of Ca and Co,and improved electrical conductivity.CaCo_2O_4can be developed as a highly active and earth-abundant catalyst for OER in energy conversion and storage technologies.
基金supported by the National Natural Science Foundation of China(Grant No.21174131)
文摘The driven self-assembly behaviors of hard nanoplates on soft elastic shells are investigated by using molecular dynamics (MD) simulation method, and the driven self-assembly structures of adsorbed hard nanoplates depend on the shape of hard nanoplates and the bending energy of soft elastic shells. Three main structures for adsorbed hard nanoplates, including the ordered aggregation structures of hard nanoplates for elastic shells with a moderate bending energy, the collapsed structures for elastic shells with a low bending energy, and the disordered aggregation structures for hard shells, are observed. The self-assembly process of adsorbed hard nanoplates is driven by the surface tension of the elastic shell, and the shape of driven self-assembly structures is determined on the basis of the minimization of the second moment of mass distribution. Meanwhile, the deformations of elastic shells can be controlled by the number of adsorbed rods as well as the length of adsorbed rods. This investigation can help us understand the complexity of the driven self-assembly of hard nanoplates on elastic shells.
基金supported by the National Natural Science Foundation of China(Nos.12072253,11972176,and 12062011)the Doctoral Science Fund of Lanzhou University of Technology of China(No.062002)the Opening Project from the State Key Laboratory for Strength and Vibration of Mechanical Structures of China(No.SV2021-KF-19)。
文摘In this paper,to better reveal the surface effect and the screening effect as well as the nonlinear multi-field coupling characteristic of the multifunctional piezoelectric semiconductor(PS)nanodevice,and to further improve its working performance,a magneto-mechanical-thermo coupling theoretical model is theoretically established for the extensional analysis of a three-layered magneto-electro-semiconductor coupling laminated nanoplate with the surface effect.Next,by using the current theoretical model,some numerical analyses and discussion about the surface effect,the corresponding critical thickness of the nanoplate,and the distributions of the physical fields(including the electron concentration perturbation,the electric potential,the electric field,the average electric displacement,the effective polarization charge density,and the total charge density)under different initial state electron concentrations,as well as their active manipulation via some external magnetic field,pre-stress,and temperature stimuli,are performed.Utilizing the nonlinear multi-field coupling effect induced by inevitable external stimuli in the device operating environment,this paper not only provides theoretical support for understanding the size-dependent tuning/controlling of carrier transport as well as its screening effect,but also assists the design of a series of multiferroic PS nanodevices.
基金Supported by the National Natural Science Foundation of China(Nos.20331010,20671011,90406024and90406002)the 111 Project(No.B07012)the Key Laboratory of Structural Chemistry Foundation(No.060017).
文摘β-Co(OH)2 and Mg(OH)2 nanoplates were synthesized via a facile template-free hydrothermal approach.The different conditions of preparation and catalytic properties of the products were studied and discussed.The products were characterized by X-ray diffraction,transmission electron microscopy,scanning electron microscopy,selected area electron diffraction(SAED),and gas chromatograph.