This paper extends the one-dimensional(1D)nonlocal strain gradient integral model(NStraGIM)to the two-dimensional(2D)Kirchhoff axisymmetric nanoplates,based on nonlocal strain gradient integral relations formulated al...This paper extends the one-dimensional(1D)nonlocal strain gradient integral model(NStraGIM)to the two-dimensional(2D)Kirchhoff axisymmetric nanoplates,based on nonlocal strain gradient integral relations formulated along both the radial and circumferential directions.By transforming the proposed integral constitutive equations into the equivalent differential forms,complemented by the corresponding constitutive boundary conditions(CBCs),a well-posed mathematical formulation is established for analyzing the axisymmetric bending and buckling of annular/circular functionally graded(FG)sandwich nanoplates.The boundary conditions at the inner edge of a solid nanoplate are derived by L'H?spital's rule.The numerical solution is obtained by the generalized differential quadrature method(GDQM).The accuracy of the proposed model is validated through comparison with the data from the existing literature.A parameter study is conducted to demonstrate the effects of FG sandwich parameters,size parameters,and nonlocal gradient parameters.展开更多
The effect of reducing agents and surfactants on controlling the silver nanoplates was studied. Two reducing agents, trisodium citrate dehydrate (TSC) and potassium tartrate, were used to reduce the AgNO3 solution. In...The effect of reducing agents and surfactants on controlling the silver nanoplates was studied. Two reducing agents, trisodium citrate dehydrate (TSC) and potassium tartrate, were used to reduce the AgNO3 solution. In this redox system, polyvinylpyrrolidone (PVP), sodium dodecyl sulfate (SDS) and arabic gum were served as surfactants. The results showed that reducing agents and surfactants both act as the capping agent adhering to the certain facets of silver seeds to block this surface to grow. The relative intensity of reducing agents also takes an active part in influencing the growth rate and direction of silver seeds. It was also found that halides can accelerate the speed of Ostwald ripening by adding Cl?, Br? and I?into the aqueous and have some effects on the morphology of the nanoplates.展开更多
In this study,we showed that BiO Br nanoplates prepared at different pH values have substratedependent photocatalytic activities under visible-light irradiation. The BiO Br nanoplates synthesized at pH 1（BOB-1） degr...In this study,we showed that BiO Br nanoplates prepared at different pH values have substratedependent photocatalytic activities under visible-light irradiation. The BiO Br nanoplates synthesized at pH 1（BOB-1） degraded salicylic acid more effectively than did those obtained at pH 3（BOB-3）,but the order of their photocatalytic activities in rhodamine B（RhB） degradation were reversed. Electrochemical Mott–Schottky and zeta-potential measurements showed that BOB-1 had a more positive valence band and lower surface charge,leading to superior photocatalytic activity in salicylic acid degradation under visible light. However,BOB-3 was more powerful in RhB degradation because larger numbers of superoxide radicals were generated via electron injection from the excited RhB to its more negative conduction band under visible-light irradiation; this was confirmed using active oxygen species measurements and electron spin resonance analysis. This study deepens our understanding of the origins of organic-pollutant-dependent photoreactivities of semiconductors,and will help in designing highly active photocatalysts for environmental remediation.展开更多
Silver nanoplates,with average thickness about 5 nm and average tunable size from 40 to 500 nm,were synthesized via a simple room-temperature solution-phase chemical reduction method in the presence of appropriate con...Silver nanoplates,with average thickness about 5 nm and average tunable size from 40 to 500 nm,were synthesized via a simple room-temperature solution-phase chemical reduction method in the presence of appropriate concentration of trisodium citrate and silver seeds.The optical in-plane dipole plasmon resonance bands of these silver plates could be tuned from 520 to 1100 nm.Control experiments were explored for understanding of the growth mechanism.It is found that both the amount of citrate ions and the small silver seeds added to the growth solution are the key to controlling the silver nanoplates without changing their thickness and crystal structure.Small silver seeds are found to play an important role in the formation of large thin silver nanoplates when poly（vinylpyrrolidone）（PVP） are used as capping agent.展开更多
To synthesize graphene economically and efficiently,as well as to improve the interface bonding between graphene and metal and to recede the aggregation issue of graphene,in this work,an easy and scalable bottom-up st...To synthesize graphene economically and efficiently,as well as to improve the interface bonding between graphene and metal and to recede the aggregation issue of graphene,in this work,an easy and scalable bottom-up strategy for the mass production of metal nanoparticles modified graphene nanoplates(GNPs)was proposed.Cu nanoparticles modified GNPs(Cu-GNPs)and Ni nanoparticles modified GNPs(Ni-GNPs)were fabricated through this method,and then compounded with Al via ball milling technique.The asobtained Ni-GNPs/Al composite showed simultaneously improved strength and toughness compared with unreinforced Al,while the Cu-GNPs/Al composite presented a greater strengthening effect.The microstructure and interface of the two composites were carefully characterized and investigated to reveal the difference.First principle study was also adopted to explore the binding energy of different interface structures.This study could provide new insights into the fabrication of GNPs and the control of interface in GNPs/Al composites.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
The effects of the post-deformation annealing on the microstructural evolution of hot rolled Al7075 matrix composites reinforced with CNTs and GNPs were investigated.The multi-pass hot rolling was applied on the stir ...The effects of the post-deformation annealing on the microstructural evolution of hot rolled Al7075 matrix composites reinforced with CNTs and GNPs were investigated.The multi-pass hot rolling was applied on the stir cast samples.Annealing was then applied to the composites at 450℃ for 4 h.Microstructural evolution was examined by SEM,EDS,and EBSD techniques.EBSD data showed that the addition of 0.87 vol.%(GNPs+CNTs)significantly inhibited the occurrence of recrystallization.Also,in the composite with 0.96 vol.%CNTs,recrystallization was partially inhibited.Whereas,in composites with 0.92 vol.%of GNPs,the occurrence of recrystallization through particle stimulated nucleation(PSN)mechanism was significantly accelerated.The volume fraction of recrystallized grains depends significantly on the occurrence of PSN in the presence of reinforcements.The intensity and type of the main components of the texture as well as the FCC fibers depend on the type of reinforcement.展开更多
Non-layered two-dimensional(2D) lead-free all-inorganic perovskites nanoplates have recently attracted considerable attention in photodetectors;however, the indepth investigation of thickness on photodetection perform...Non-layered two-dimensional(2D) lead-free all-inorganic perovskites nanoplates have recently attracted considerable attention in photodetectors;however, the indepth investigation of thickness on photodetection performance is still lacking. In this work, by constructing the famous metal-semiconductor-metal photodetectors, the photodetection behaviors of thickness-controlled CsSnBr;nanoplates are investigated systematically. Ni electrodes are adopted for ensuring the good ohmic contact behaviors of as-fabricated photodetectors. With the increase in thickness, the photodetection performances improve accordingly, such as photocurrent increases from 0.22 to 19.40 nA, responsivity increases from 72.9 to 4893.7 mA·W^(-1), rise/decay time decreases from 11/35 to 3/10 ms, respectively. Notability, the dark current also increases with the increase in thickness, making the further investigation on the reduction in dark current meaningful.All of the as-fabricated photodetectors are stable, suggesting the careful thickness selection in next-generation high-performance lead-free all-inorganic perovskites photodetectors.展开更多
Due to the serious harm of diabetes to human health,development of sensitive assays for glucose level is of high significance for early prevention and treatment of diabetes.Currently,most conventional enzyme-based glu...Due to the serious harm of diabetes to human health,development of sensitive assays for glucose level is of high significance for early prevention and treatment of diabetes.Currently,most conventional enzyme-based glucose sensors suffer from high cost and low stability due to the inherent defects of natural enzymes.Herein,we develop a pure nanozyme-based glucose detection method using Ag@Au core/shell triangular nanoplates(TNPs),which combines glucose oxidase(GOD)-and horseradish peroxidase(HRP)-like activities of the Au shell and inherent plasmonic properties of Ag TNPs.The sensing mechanism is based on the fact that the Au shell possessed GOD-like activity,enabling the oxidation of glucose to produce H2O2,which can further etch the silver core,leading to the decrease of absorbance at 800 nm and the color change from blue to colorless.Compared with the previous nanozymes-based glucose sensors,our method avoids the use of enzymes and organic chromogenic agent.Moreover,the stability of the Ag@Au core/shell TNPs is much better than that of Ag TNPs due to the protection by the coating of the Au shell.This method was successfully applied to the detection of urine samples from patients with diabetes,indicating its practical applicability for real sample analysis.展开更多
Αn analytical method is developed to explore the wave propagation characteristics of piezoelectric sandwich nanoplates in the present work.The sandwich nanoplates are composed of a graphene reinforced composite core ...Αn analytical method is developed to explore the wave propagation characteristics of piezoelectric sandwich nanoplates in the present work.The sandwich nanoplates are composed of a graphene reinforced composite core layer with two piezoelectric surface layers exposed to electric field.The material properties of the nanocomposite layer are given by the Halpin–Tsai model and mixture’s rule.The Euler–Lagrange equation of the nanoplates is obtained by Hamilton's principle and first-order shear deformation theory.Then,combining the high-order nonlocal strain gradient theory with the hygrothermal constitutive relationship of composite nanoplates,the nonlocal governing equations are presented.Finally,numerical studies are conducted to demonstrate the influences of scale parameters,applied external voltage,temperature variation,moisture variation,graphene size,and weight fraction on wave frequency.The results reveal that low-order and high-order nonlocal parameters and length scale parameters have different effects on wave frequency.The wave frequency can be reduced by increasing temperature and the thickness of graphene.This could facilitate the investigation of the dynamic properties of graphene nanocomposite structures.展开更多
In this study,the nonlocal strain gradient theory is adopted to investigate the static bending deformation of a functionally graded(FG)multilayered nanoplate made of onedimensional hexagonal piezoelectric quasicrystal...In this study,the nonlocal strain gradient theory is adopted to investigate the static bending deformation of a functionally graded(FG)multilayered nanoplate made of onedimensional hexagonal piezoelectric quasicrystal(PQC)materials subjected to mechanical and electrical surface loadings.The FG materials are assumed to be exponential distribution along the thickness direction.Exact closed-form solutions of an FG PQC nanoplate including nonlocality and strain gradient micro-size dependency are derived by utilizing the pseudo-Stroh formalism.The propagator matrix method is further used to solve the multilayered case by assuming that the layer interfaces are perfectly contacted.Numerical examples for two FG sandwich nanoplates made of piezoelectric crystals and PQC are provided to show the influences of nonlocal parameter,strain gradient parameter,exponential factor,length-to-width ratio,loading form,and stacking sequence on the static deformation of two FG sandwich nanoplates,which play an important role in designing new smart composite structures in engineering.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
An easy and effective method of silver nanoplate synthesis technique was created by reducing silver nitrate （AgNO3） with hydroxylamine hydrochloride （NH2OH·HCl） at room temperature. Silver nanoplates of vario...An easy and effective method of silver nanoplate synthesis technique was created by reducing silver nitrate （AgNO3） with hydroxylamine hydrochloride （NH2OH·HCl） at room temperature. Silver nanoplates of various shapes, including triangular, truncated triangular, hexagonal, and truncated hexagonal, exhibit an average width and thickness of approximately 1 μm and 50 nm, respectively. Silver nanoparticles were acquired by placing polyvinyl pyrrolidone （PVP） in the reaction solution. The produced silver nanoparticles are quasi-spherical in shape and - 100 nm in size. The catalytic activity in the thermal decomposition of ammonium perchlorate （AID） was distinguished by thermogravimetric （TG） analysis and differential scanning calorimetry （DSC）. The outcomes reveal that the addition of silver nanoplates and nanoparticles diminishes the low decomposition temperature of AP by 7 and 14 ℃ and leads to a drop in the high decomposition temperature of AP by 60 and 110 ℃ and a rise in the total DSC heat release by 0.86 and 1.05 kJ.g^-1, respectively.展开更多
This research develops an analytical approach to explore the wave propagation problem of piezoelectric sandwich nanoplates.The core of the sandwich nanoplates is a nanocomposite layer reinforced with graphene platelet...This research develops an analytical approach to explore the wave propagation problem of piezoelectric sandwich nanoplates.The core of the sandwich nanoplates is a nanocomposite layer reinforced with graphene platelets,which is integrated by two piezoelectric layers exposed to electric field.The material properties of nanocomposite layer are obtained by the Halpin–Tsai model and the rule of mixtures.The Euler–Lagrange equations of nanoplates are derived from Hamilton’s principle.By using the nonlocal strain gradient theory,the nonlocal governing equations are presented.Finally,numerical studies are conducted to demonstrate the influences of propagation angle,small-scale and external loads on wave frequency.The results reveal that the frequency changes periodically with the propagation angle and can be reduced by increasing voltage,temperature and the thickness of graphene platelets.展开更多
The exposed crystal facet of TiO_(2) is a crucial factor influencing the gas sensing properties.TiO_(2) with high-energy{001}crystal facets that have higher surface energy and reactivity is expected to exhibit excelle...The exposed crystal facet of TiO_(2) is a crucial factor influencing the gas sensing properties.TiO_(2) with high-energy{001}crystal facets that have higher surface energy and reactivity is expected to exhibit excellent gas-sensing properties.In this paper,TiO_(2) nanoplates with defective{001}facets were synthesized by chemical etching via one-step hydrothermal method.We carefully explored the gas-sensing performance of TiO_(2) nanoplates with defective and complete{001}facets towards acetone.The results show that the sensing response of TiO_(2) nanoplates with complete{001}facets is 70%higher than that of defective TiO_(2) nanoplates,which proves that the{001}facets plays a vital role in improving the gas sensing performance of TiO_(2).It is speculated that the poor gas sensitivity of defective TiO_(2) can be contributed to fewer adsorption sites and blocked electron transfer.This work presents a more direct evidence for explaining the important role of the complete{001}crystal facets in high sensitivity of TiO_(2) and also provides a new insight for preparing high sensitivity sensing materials.展开更多
Sliver nanoplates were prepared through a visible light induced reduction process by a reaction between sodium citrate and silver nitrate in an aqueous solvent at room temperature. UV-Vis spectra were employed to moni...Sliver nanoplates were prepared through a visible light induced reduction process by a reaction between sodium citrate and silver nitrate in an aqueous solvent at room temperature. UV-Vis spectra were employed to monitor the growth of the silver nanoplates. The resulting spectra indicated that, at an early stage, the products were spherical particles with planar nanoparticles appearing and growing subsequently. In the last stages of the process, some spherical particles were consumed by the growth of the nanoparticles, through an Ostwald ripening mechanism. Furthermore, it was found that the addition of either Poly（Vinyl Pyrrolidone） （PVP） or excessive citrate could stabilize the colloidal system effectively, and that rigorous stirring was necessary for the anticipant products, Introduction of a large quantities of sodium hydroxide can dramatically accelerate the reactive rate of the photoreduction process.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
Silver nanoplates were synthesized in aqueous solution by photoinduced chemical reduction method with tungsten lamp as light source.The growth process was analyzed and characterized.The linear absorption spectra showe...Silver nanoplates were synthesized in aqueous solution by photoinduced chemical reduction method with tungsten lamp as light source.The growth process was analyzed and characterized.The linear absorption spectra showed that,along with the growth process,the surface plasmon resonance of silver seed nanoparticles at 395 nm decreased gradually,while a new plasmon band at 740 nm corresponding to silver nanoplates appeared and increased gradually.Z-scan technique was used to explore the nonlinear optical properties of silver nanoplates.The results displayed that with the reaction time increases from 0 h to 24 h,the value of nonlinear absorption（NLA） coefficient and the value of nonlinear refraction（NLR） index of the products increased from 0 to 3.167 cm/GW and from 0.64×10^ 4 to 6.83×10 ^4 cm 2 /GW,respectively.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
We herein report a one-step, wet-chemical approach to synthesizing gold nanoplates in large quantities via the AuCl4^- thermal reduction process by aniline, without introducing additional capping agent or surfactant. ...We herein report a one-step, wet-chemical approach to synthesizing gold nanoplates in large quantities via the AuCl4^- thermal reduction process by aniline, without introducing additional capping agent or surfactant. It is found that the reduction kinetics of AuCl4^- is greatly altered by varying the initial molar ratio of aniline to AuCl4^-. Moreover, further investigation reveals that the insitu formed polyaniline could serve effectively as a capping agent to preferably adsorb the { 1 1 1 } facets of gold crystals during a slow reduction process, directing the formation of gold nanoplates.展开更多
基金Project supported by the National Natural Science Foundation of China(No.12172169)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘This paper extends the one-dimensional(1D)nonlocal strain gradient integral model(NStraGIM)to the two-dimensional(2D)Kirchhoff axisymmetric nanoplates,based on nonlocal strain gradient integral relations formulated along both the radial and circumferential directions.By transforming the proposed integral constitutive equations into the equivalent differential forms,complemented by the corresponding constitutive boundary conditions(CBCs),a well-posed mathematical formulation is established for analyzing the axisymmetric bending and buckling of annular/circular functionally graded(FG)sandwich nanoplates.The boundary conditions at the inner edge of a solid nanoplate are derived by L'H?spital's rule.The numerical solution is obtained by the generalized differential quadrature method(GDQM).The accuracy of the proposed model is validated through comparison with the data from the existing literature.A parameter study is conducted to demonstrate the effects of FG sandwich parameters,size parameters,and nonlocal gradient parameters.
基金Project(51373097)supported by The National Natural Science Foundation of China
文摘The effect of reducing agents and surfactants on controlling the silver nanoplates was studied. Two reducing agents, trisodium citrate dehydrate (TSC) and potassium tartrate, were used to reduce the AgNO3 solution. In this redox system, polyvinylpyrrolidone (PVP), sodium dodecyl sulfate (SDS) and arabic gum were served as surfactants. The results showed that reducing agents and surfactants both act as the capping agent adhering to the certain facets of silver seeds to block this surface to grow. The relative intensity of reducing agents also takes an active part in influencing the growth rate and direction of silver seeds. It was also found that halides can accelerate the speed of Ostwald ripening by adding Cl?, Br? and I?into the aqueous and have some effects on the morphology of the nanoplates.
基金supported by the National Natural Science Funds for Distinguished Young Scholars(21425728)the National Natural Science Foundation of China(21173093+4 种基金211770482127308821477044)the Key Project of Natural Science Foundation of Hubei Province(2013CFA114)the the Fundamental Research Funds for the Central Universities(CCNU14Z01001 CCNU14KFY002)~~
文摘In this study,we showed that BiO Br nanoplates prepared at different pH values have substratedependent photocatalytic activities under visible-light irradiation. The BiO Br nanoplates synthesized at pH 1（BOB-1） degraded salicylic acid more effectively than did those obtained at pH 3（BOB-3）,but the order of their photocatalytic activities in rhodamine B（RhB） degradation were reversed. Electrochemical Mott–Schottky and zeta-potential measurements showed that BOB-1 had a more positive valence band and lower surface charge,leading to superior photocatalytic activity in salicylic acid degradation under visible light. However,BOB-3 was more powerful in RhB degradation because larger numbers of superoxide radicals were generated via electron injection from the excited RhB to its more negative conduction band under visible-light irradiation; this was confirmed using active oxygen species measurements and electron spin resonance analysis. This study deepens our understanding of the origins of organic-pollutant-dependent photoreactivities of semiconductors,and will help in designing highly active photocatalysts for environmental remediation.
基金Project (10804101) supported by the National Nature Science Foundation of ChinaProject (2007CB815102) supported by the National Basic Research Program of ChinaProject (2007B08007) supported by the Science and Technology Development Foundation of Chinese Academy of Engineering Physics
文摘Silver nanoplates,with average thickness about 5 nm and average tunable size from 40 to 500 nm,were synthesized via a simple room-temperature solution-phase chemical reduction method in the presence of appropriate concentration of trisodium citrate and silver seeds.The optical in-plane dipole plasmon resonance bands of these silver plates could be tuned from 520 to 1100 nm.Control experiments were explored for understanding of the growth mechanism.It is found that both the amount of citrate ions and the small silver seeds added to the growth solution are the key to controlling the silver nanoplates without changing their thickness and crystal structure.Small silver seeds are found to play an important role in the formation of large thin silver nanoplates when poly（vinylpyrrolidone）（PVP） are used as capping agent.
基金the National Natural Science Foundation of China(Grant Nos.51771130,51531004,and 51422104)the Tianjin youth talent support program+1 种基金the Tianjin Natural Science Funds for Distinguished Young(Grant No.17JCJQJC44300)the Tianjin Science and Technology Support Project(Grant No.17ZXCLGX00060)。
文摘To synthesize graphene economically and efficiently,as well as to improve the interface bonding between graphene and metal and to recede the aggregation issue of graphene,in this work,an easy and scalable bottom-up strategy for the mass production of metal nanoparticles modified graphene nanoplates(GNPs)was proposed.Cu nanoparticles modified GNPs(Cu-GNPs)and Ni nanoparticles modified GNPs(Ni-GNPs)were fabricated through this method,and then compounded with Al via ball milling technique.The asobtained Ni-GNPs/Al composite showed simultaneously improved strength and toughness compared with unreinforced Al,while the Cu-GNPs/Al composite presented a greater strengthening effect.The microstructure and interface of the two composites were carefully characterized and investigated to reveal the difference.First principle study was also adopted to explore the binding energy of different interface structures.This study could provide new insights into the fabrication of GNPs and the control of interface in GNPs/Al composites.
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.
基金the Sahand University of Technology and Ghent University for the support of this research。
文摘The effects of the post-deformation annealing on the microstructural evolution of hot rolled Al7075 matrix composites reinforced with CNTs and GNPs were investigated.The multi-pass hot rolling was applied on the stir cast samples.Annealing was then applied to the composites at 450℃ for 4 h.Microstructural evolution was examined by SEM,EDS,and EBSD techniques.EBSD data showed that the addition of 0.87 vol.%(GNPs+CNTs)significantly inhibited the occurrence of recrystallization.Also,in the composite with 0.96 vol.%CNTs,recrystallization was partially inhibited.Whereas,in composites with 0.92 vol.%of GNPs,the occurrence of recrystallization through particle stimulated nucleation(PSN)mechanism was significantly accelerated.The volume fraction of recrystallized grains depends significantly on the occurrence of PSN in the presence of reinforcements.The intensity and type of the main components of the texture as well as the FCC fibers depend on the type of reinforcement.
基金the National Key R&D Program of China(No.2017YFA0305500)the National Natural Science Foundation of China(Nos.61904096 and 62104133)+3 种基金Taishan Scholars Program of Shandong Province(No.tsqn201812006)Shandong University Youth Innovation Supporting Program(No.2019KJN020)Shandong University Multidisciplinary Research and Innovation Team of Young Scholars(No.2020QNQT015)‘‘Outstanding Youth Scholar and Qilu Young Scholar’’programs of Shandong University。
文摘Non-layered two-dimensional(2D) lead-free all-inorganic perovskites nanoplates have recently attracted considerable attention in photodetectors;however, the indepth investigation of thickness on photodetection performance is still lacking. In this work, by constructing the famous metal-semiconductor-metal photodetectors, the photodetection behaviors of thickness-controlled CsSnBr;nanoplates are investigated systematically. Ni electrodes are adopted for ensuring the good ohmic contact behaviors of as-fabricated photodetectors. With the increase in thickness, the photodetection performances improve accordingly, such as photocurrent increases from 0.22 to 19.40 nA, responsivity increases from 72.9 to 4893.7 mA·W^(-1), rise/decay time decreases from 11/35 to 3/10 ms, respectively. Notability, the dark current also increases with the increase in thickness, making the further investigation on the reduction in dark current meaningful.All of the as-fabricated photodetectors are stable, suggesting the careful thickness selection in next-generation high-performance lead-free all-inorganic perovskites photodetectors.
基金supported by the National Natural Science Foundation of China(No.21876206)the Fundamental Research Funds for the Central Universities(No.18CX02037A)。
文摘Due to the serious harm of diabetes to human health,development of sensitive assays for glucose level is of high significance for early prevention and treatment of diabetes.Currently,most conventional enzyme-based glucose sensors suffer from high cost and low stability due to the inherent defects of natural enzymes.Herein,we develop a pure nanozyme-based glucose detection method using Ag@Au core/shell triangular nanoplates(TNPs),which combines glucose oxidase(GOD)-and horseradish peroxidase(HRP)-like activities of the Au shell and inherent plasmonic properties of Ag TNPs.The sensing mechanism is based on the fact that the Au shell possessed GOD-like activity,enabling the oxidation of glucose to produce H2O2,which can further etch the silver core,leading to the decrease of absorbance at 800 nm and the color change from blue to colorless.Compared with the previous nanozymes-based glucose sensors,our method avoids the use of enzymes and organic chromogenic agent.Moreover,the stability of the Ag@Au core/shell TNPs is much better than that of Ag TNPs due to the protection by the coating of the Au shell.This method was successfully applied to the detection of urine samples from patients with diabetes,indicating its practical applicability for real sample analysis.
基金This work was supported in part by the National Natural Science Foundation of China(Grants 11502218,11672252,and 11602204)the Fundamental Research Funds for the Central Universities of China(Grant 2682020ZT106).
文摘Αn analytical method is developed to explore the wave propagation characteristics of piezoelectric sandwich nanoplates in the present work.The sandwich nanoplates are composed of a graphene reinforced composite core layer with two piezoelectric surface layers exposed to electric field.The material properties of the nanocomposite layer are given by the Halpin–Tsai model and mixture’s rule.The Euler–Lagrange equation of the nanoplates is obtained by Hamilton's principle and first-order shear deformation theory.Then,combining the high-order nonlocal strain gradient theory with the hygrothermal constitutive relationship of composite nanoplates,the nonlocal governing equations are presented.Finally,numerical studies are conducted to demonstrate the influences of scale parameters,applied external voltage,temperature variation,moisture variation,graphene size,and weight fraction on wave frequency.The results reveal that low-order and high-order nonlocal parameters and length scale parameters have different effects on wave frequency.The wave frequency can be reduced by increasing temperature and the thickness of graphene.This could facilitate the investigation of the dynamic properties of graphene nanocomposite structures.
基金supported by the National Natural Science Foundation of China(Grant Nos.11862021,12072166)the Program for Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(Grant No.NJYT-19-A06)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(Grant Nos.2020MS01006,2019MS01015,2019MS01017).
文摘In this study,the nonlocal strain gradient theory is adopted to investigate the static bending deformation of a functionally graded(FG)multilayered nanoplate made of onedimensional hexagonal piezoelectric quasicrystal(PQC)materials subjected to mechanical and electrical surface loadings.The FG materials are assumed to be exponential distribution along the thickness direction.Exact closed-form solutions of an FG PQC nanoplate including nonlocality and strain gradient micro-size dependency are derived by utilizing the pseudo-Stroh formalism.The propagator matrix method is further used to solve the multilayered case by assuming that the layer interfaces are perfectly contacted.Numerical examples for two FG sandwich nanoplates made of piezoelectric crystals and PQC are provided to show the influences of nonlocal parameter,strain gradient parameter,exponential factor,length-to-width ratio,loading form,and stacking sequence on the static deformation of two FG sandwich nanoplates,which play an important role in designing new smart composite structures in engineering.
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financially supported by the National Natural Science Foundation of China (No.51676082)Qing Lan Project of Jiangsu Provincethe Innovation Experiment Program for University Students of Jiangsu (201710323075X)
文摘An easy and effective method of silver nanoplate synthesis technique was created by reducing silver nitrate （AgNO3） with hydroxylamine hydrochloride （NH2OH·HCl） at room temperature. Silver nanoplates of various shapes, including triangular, truncated triangular, hexagonal, and truncated hexagonal, exhibit an average width and thickness of approximately 1 μm and 50 nm, respectively. Silver nanoparticles were acquired by placing polyvinyl pyrrolidone （PVP） in the reaction solution. The produced silver nanoparticles are quasi-spherical in shape and - 100 nm in size. The catalytic activity in the thermal decomposition of ammonium perchlorate （AID） was distinguished by thermogravimetric （TG） analysis and differential scanning calorimetry （DSC）. The outcomes reveal that the addition of silver nanoplates and nanoparticles diminishes the low decomposition temperature of AP by 7 and 14 ℃ and leads to a drop in the high decomposition temperature of AP by 60 and 110 ℃ and a rise in the total DSC heat release by 0.86 and 1.05 kJ.g^-1, respectively.
基金This work was supported in part by the National Natural Science Foundation of China(Grant Nos.11502218,11672252 and 11602204)the Fundamental Research Funds for the Central Universities of China(Grant No.2682020ZT106).
文摘This research develops an analytical approach to explore the wave propagation problem of piezoelectric sandwich nanoplates.The core of the sandwich nanoplates is a nanocomposite layer reinforced with graphene platelets,which is integrated by two piezoelectric layers exposed to electric field.The material properties of nanocomposite layer are obtained by the Halpin–Tsai model and the rule of mixtures.The Euler–Lagrange equations of nanoplates are derived from Hamilton’s principle.By using the nonlocal strain gradient theory,the nonlocal governing equations are presented.Finally,numerical studies are conducted to demonstrate the influences of propagation angle,small-scale and external loads on wave frequency.The results reveal that the frequency changes periodically with the propagation angle and can be reduced by increasing voltage,temperature and the thickness of graphene platelets.
基金financially supported by the National Natural Science Foundation of China(Nos.51773226,61701514)the Natural Science Foundation of Hunan Province(No.2018JJ3603)
文摘The exposed crystal facet of TiO_(2) is a crucial factor influencing the gas sensing properties.TiO_(2) with high-energy{001}crystal facets that have higher surface energy and reactivity is expected to exhibit excellent gas-sensing properties.In this paper,TiO_(2) nanoplates with defective{001}facets were synthesized by chemical etching via one-step hydrothermal method.We carefully explored the gas-sensing performance of TiO_(2) nanoplates with defective and complete{001}facets towards acetone.The results show that the sensing response of TiO_(2) nanoplates with complete{001}facets is 70%higher than that of defective TiO_(2) nanoplates,which proves that the{001}facets plays a vital role in improving the gas sensing performance of TiO_(2).It is speculated that the poor gas sensitivity of defective TiO_(2) can be contributed to fewer adsorption sites and blocked electron transfer.This work presents a more direct evidence for explaining the important role of the complete{001}crystal facets in high sensitivity of TiO_(2) and also provides a new insight for preparing high sensitivity sensing materials.
文摘Sliver nanoplates were prepared through a visible light induced reduction process by a reaction between sodium citrate and silver nitrate in an aqueous solvent at room temperature. UV-Vis spectra were employed to monitor the growth of the silver nanoplates. The resulting spectra indicated that, at an early stage, the products were spherical particles with planar nanoparticles appearing and growing subsequently. In the last stages of the process, some spherical particles were consumed by the growth of the nanoparticles, through an Ostwald ripening mechanism. Furthermore, it was found that the addition of either Poly（Vinyl Pyrrolidone） （PVP） or excessive citrate could stabilize the colloidal system effectively, and that rigorous stirring was necessary for the anticipant products, Introduction of a large quantities of sodium hydroxide can dramatically accelerate the reactive rate of the photoreduction process.
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Supported by the National Natural Science Foundation of China(11174229)
文摘Silver nanoplates were synthesized in aqueous solution by photoinduced chemical reduction method with tungsten lamp as light source.The growth process was analyzed and characterized.The linear absorption spectra showed that,along with the growth process,the surface plasmon resonance of silver seed nanoparticles at 395 nm decreased gradually,while a new plasmon band at 740 nm corresponding to silver nanoplates appeared and increased gradually.Z-scan technique was used to explore the nonlinear optical properties of silver nanoplates.The results displayed that with the reaction time increases from 0 h to 24 h,the value of nonlinear absorption（NLA） coefficient and the value of nonlinear refraction（NLR） index of the products increased from 0 to 3.167 cm/GW and from 0.64×10^ 4 to 6.83×10 ^4 cm 2 /GW,respectively.
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supported by the National Natural Science Foundation of China(Nos.90406023,60571031 and 60501009)the National Important Science Research Program of China(No.2006CB933206).
文摘We herein report a one-step, wet-chemical approach to synthesizing gold nanoplates in large quantities via the AuCl4^- thermal reduction process by aniline, without introducing additional capping agent or surfactant. It is found that the reduction kinetics of AuCl4^- is greatly altered by varying the initial molar ratio of aniline to AuCl4^-. Moreover, further investigation reveals that the insitu formed polyaniline could serve effectively as a capping agent to preferably adsorb the { 1 1 1 } facets of gold crystals during a slow reduction process, directing the formation of gold nanoplates.
