The current work is an extension of the nonlocal elasticity theory to fractional order thermo-elasticity in semiconducting nanostructure medium with voids.The analysis is made on the reflection phenomena in context of...The current work is an extension of the nonlocal elasticity theory to fractional order thermo-elasticity in semiconducting nanostructure medium with voids.The analysis is made on the reflection phenomena in context of three-phase-lag thermo-elastic model.It is observed that,four-coupled longitudinal waves and an independent shear vertical wave exist in the medium which is dispersive in nature.It is seen that longitudinal waves are damped,and shear wave is un-damped when angular frequency is less than the cut-off frequency.The voids,thermal and non-local parameter affect the dilatational waves whereas shear wave is only depending upon non-local parameter.It is found that reflection coefficients are affected by nonlocal and fractional order parameters.Reflection coefficients are calculated analytically and computed numerically for a material,silicon and discussed graphically in details.The results for local(classical)theory are obtained as a special case.The study may be useful in semiconductor nanostructure,geology and seismology in addition to semiconductor nanostructure devices.展开更多
Nanostructured FeS-SiC coating was deposited by atmospheric plasma spraying（APS）.The microstructure and phase composition of the coating were characterized with SEM and XRD,respectively.In addition,the size distribu...Nanostructured FeS-SiC coating was deposited by atmospheric plasma spraying（APS）.The microstructure and phase composition of the coating were characterized with SEM and XRD,respectively.In addition,the size distribution of the reconstituted powders and the porosity of the coating have been measured.It was found that the reconstitiuted powers with sizes in the range of 20 to 80 μm had excellent flowability and were suitable for plasma spraying process.The as-sprayed FeS-SiC composite coating exhibited a bimodal distribution with small grains（30～80nm） and large grains（100～200nm）.The coating was mainly composed of FeS and SiC,a small quantity of Fe1-xS and oxide were also found.The porosity of the coating was approximately 19%.展开更多
Diesel soot subjected to high exhaust temperature suffers from thermal ageing,which is difficult to be removed by regeneration process.Based on the thermogravimetric(TG)analysis and images by high resolution transmiss...Diesel soot subjected to high exhaust temperature suffers from thermal ageing,which is difficult to be removed by regeneration process.Based on the thermogravimetric(TG)analysis and images by high resolution transmission electron microscope(HRTEM),effects of thermal ageing temperature,ageing time and oxygen concentration on oxidation characteristic of soot are investigated.The activation energy of soot increases with the increase of ageing temperature and oxygen concentration.The activation energy increases rapidly when the ageing time is less than 45 min,and then it keeps in a value of 157 kJ/mol when the ageing time is between 45 and 60 min.Compared to the soot without thermal ageing,the shape of ageing soot particles presents shorter diameter and more regular circle by observing soot nanostructure.With the increase of ageing temperature,ageing time and oxygen concentration,the more stable structure of“shell and core”is shown in the basic carbon.The soot has an increased fringe length,decreased tortuosity and separation distance after thermal ageing process,which leads to the deepening of the disorder degree of soot nanostructures and reduction of soot oxidation activity.Consequently,the thermal ageing process should be avoided in order to optimize the active regeneration strategy.展开更多
Nanostructured n-Al2O3/Ni feedstock for thermal spraying was manufactured by the method of chemical wrapping and spray drying. The nanostructured coating was sprayed with this feedstock. Tribological properties of the...Nanostructured n-Al2O3/Ni feedstock for thermal spraying was manufactured by the method of chemical wrapping and spray drying. The nanostructured coating was sprayed with this feedstock. Tribological properties of the coatings and steel 45# were tested. Within the testing range, the friction coefficient of coatings against GCr15 steel decreased and the mass loss of coatings increased at first then decreased with the increase of load. Under each load, the coatings’ friction coefficients and wear losses were lower than that of steel 45#. Scanning electron microscopy and energy dispersive spectrometer analysis show that adhesion is the dominating wear mechanism, and fatigue exists at the same time. Material transferred from counter-part to the coating is the main factor which influences the coatings’ friction coefficient and wear losses.展开更多
A nanocomposite of manganese dioxide coated manganese hexacyanoferrate was synthesized by a facile co-precipitation method and tested as active electrode material for an electrochemical supercapacitor. A way called &q...A nanocomposite of manganese dioxide coated manganese hexacyanoferrate was synthesized by a facile co-precipitation method and tested as active electrode material for an electrochemical supercapacitor. A way called "Deep electro-oxidation" was used to generate manganese dioxide coated layer for stabilizing the electrode material. The structure and ingredient of the resulting MnHCF/MnO2 composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray Photoelectron Spectroscopy. Electrochemical testing showed a capacitance of 225.6 F/g at a sweep rate of 5 mV/s within a voltage range of 1.3 V, and high energy density of 37.2 Wh/kg at a current density of 0.5 A/g in galvanostatic charge/discharge cycling. It is suggested that the two different components, manganese hexacyanoferrate core and manganese dioxide shell, lead to an integrated electrochemical behavior, and an enhanced capacitor. The electrochemical testing and corresponding XPS analysis also demonstrated that the manganese coordinated by cyanide groups via nitrogen atoms in MnHCF did not get involved in the charge storage process during potential cycles.展开更多
In this Study,Cadmium Oxide(CdO)nanostructures were synthesized by using Chemical Bath Deposition Technique.The synthesized process was carried out at room temperature.The structural and optical properties of nanostru...In this Study,Cadmium Oxide(CdO)nanostructures were synthesized by using Chemical Bath Deposition Technique.The synthesized process was carried out at room temperature.The structural and optical properties of nanostructures was characterized by XRD,SEM and UV-Vis techniques.As a result,the CdO nanostructures are oriented along(111)plane of cubic crystal structure.The morphology of CdO nanostructures showed interconnected prism-like and cauliflower-type cluster nanostructure.The UV results of this structures with high absorbtion coefficient are observed to be in accordance with the CdO nanoparticles.展开更多
Metallic nanostructures can support the strongly confined interface waves:surface plasmon polaritons(SPPs).SPPs have recently been used in a variety of applications due to their abilities to guide light in the scale o...Metallic nanostructures can support the strongly confined interface waves:surface plasmon polaritons(SPPs).SPPs have recently been used in a variety of applications due to their abilities to guide light in the scale of na-nometer.Whereas,intrinsic weak optical nonlinearities and short propagation lengths of SPPs hinder their applica-tions in novel active plasmonic devices.One promising solution is to couple SPPs to nonlinear optical resonances,such as excitons(Xs)in molecular or semiconducting nanostructures.Consequently,hybrid nanostructures containing J-aggregate molecules and metallic nanostructures have attracted considerable interest.In these systems,vacuum field fluctuations lead to a coherent ex-change of energy between ensembles of excitons and plasmons and the formation of new hybrid polariton states.Strong coupling between Xs and SPPs enables an efficient transfer of the strong optical nonlinearities of the excitonic emitters to the passive plasmonic nanostructures on the ultrashort time scale of femtosecond.展开更多
Hard carbons(HCs)are recognized as potential anode materials for sodium-ion batteries(SIBs)because of their low cost,environmental friendliness,and the abundance of their precursors.The presence of graphitic domains,n...Hard carbons(HCs)are recognized as potential anode materials for sodium-ion batteries(SIBs)because of their low cost,environmental friendliness,and the abundance of their precursors.The presence of graphitic domains,numerous pores,and disordered carbon layers in HCs plays a significant role in determining their sodium storage ability,but these structural features depend on the precursor used.The influence of functional groups,including heteroatoms and oxygen-containing groups,and the microstructure of the precursor on the physical and electrochemical properties of the HC produced are evaluated,and the effects of carbonization conditions(carbonization temperature,heating rate and atmosphere)are also discussed.展开更多
La2Zr2O7 （LZ） is a promising thermal barrier coating material for the high temperature applications. The fracture toughness and microhardness of nanocrystalline LZ （n-LZ）, microcrystalline LZ （m-LZ） and LZ-5mol%...La2Zr2O7 （LZ） is a promising thermal barrier coating material for the high temperature applications. The fracture toughness and microhardness of nanocrystalline LZ （n-LZ）, microcrystalline LZ （m-LZ） and LZ-5mol%8YSZ （LZ-5-8YSZ） composite （8YSZ for zirconia stabilized by 8 mol% ytrria） were studied. The n-LZ had a thermal expansion coefficient of （9.6±0.4）×10 -6 K -1 （200～1000℃） and fracture toughness of （1.98±0.07） MPa·m 1/2 which are obviously higher than those of the m-LZ （ （9.1±0.4）×10 -6 K -1 and （1.40±0.23） MPa·m 1/2, respectively）, indicating that nanofication was an efficient way to increase the toughness and thermal expansion coefficient of LZ. The composite LZ-5-8YSZ had a higher fracture toughness （（1.88±0.30） MPa·m 1/2） than LZ, which was close to that of 8YSZ densified by superhigh pressure （SHP）.展开更多
Surface enhanced Raman scattering(SERS)is an efficient technique to detect low concentration molecules.In this work,periodical silicon nanowires(Si NWs)integrated with metal-insulator-metal(MIM)layers are employed as ...Surface enhanced Raman scattering(SERS)is an efficient technique to detect low concentration molecules.In this work,periodical silicon nanowires(Si NWs)integrated with metal-insulator-metal(MIM)layers are employed as SERS substrates.Laser interference lithography(LIL)combined with reactive ion etching(RIE)is used to fabricate large-area periodic nanostructures,followed by decorating the MIM layers.Compared to MIM disks array on Si surface,the SERS enhancement factor(EF)of the MIM structures on the Si NWs array can be increased up to 5 times,which is attributed to the enhanced electric field at the boundary of the MIM disks.Furthermore,high density of nanoparticles and nanogaps serving as hot spots on sidewall surfaces also contribute to the enhanced SERS signals.Via changing the thickness of the insulator layer,the plasmonic resonance can be tuned,which provides a new localized surface plasmon resonance(LSPR)characteristic for SERS applications.展开更多
Developing high-performance lithium ion batteries(LIBs)using manganese oxides as anodes is attractive due to their high theoretical capacity and abundant resources.Herein,we report a facile synthesis of hierarchical s...Developing high-performance lithium ion batteries(LIBs)using manganese oxides as anodes is attractive due to their high theoretical capacity and abundant resources.Herein,we report a facile synthesis of hierarchical spherical MnO2 containing coherent amorphous/crystalline domained by a simple yet effective redox precipitation reaction at room temperature.Further,flower-like CoMn2O4 constructed by single-crystalline spinel nanosheets has been fabricated using MnO2 as precursor.This mild methodology avoids undesired particle aggregation and loss of active surface area in conventional hydrothermal or solid-state processes.Moreover,both MnO2 and CoMn2O4 nanosheets manifest superior lithium-ion storage properties,rendering them promising applications in LIBs and other energy-related fields.展开更多
Hollow-structured Cu_(0.3)Co_(2.7)O_(4) microspheres have been synthesized by a simple one-pot template-free hydrothermal method with copper sulfate,cobalt acetate and ammonia as raw materials.The products were charac...Hollow-structured Cu_(0.3)Co_(2.7)O_(4) microspheres have been synthesized by a simple one-pot template-free hydrothermal method with copper sulfate,cobalt acetate and ammonia as raw materials.The products were characterized by powder X-ray diffraction,energy dispersive X-ray analysis,selected area electron diffraction,high-resolution transmission electron microscopy,scanning electron microscopy and BET measurements.The research results show that the hollow Cu_(0.3)Co_(2.7)O_(4) microspheres consist of single-crystalline nanocubes with the diameter of about 20 nm.The formation mechanism of hollow Cu_(0.3)Co_(2.7)O_(4) microspheres is suggested as Ostwald ripening in a solid-solution-solid process,and Cu_(0.3)Co_(2.7)O_(4) microspheres are mesoporous containing two pore sizes of 3.3 and 5.9 nm.The as-prepared Cu_(0.3)Co_(2.7)O_(4) sensors have optimal gas responses to 50×10^(−6) mg/m^(3) C_(2)H_(5)OH at 190℃.展开更多
Ytterbia and erbia dual-doped zirconia(ZrO_2:Yb^(3+),Er^(3+))nanophosphors were successfully synthesized by high-temperature fuel combustion at 1000°C for 2 h.The effects of dopant concentration on the structure ...Ytterbia and erbia dual-doped zirconia(ZrO_2:Yb^(3+),Er^(3+))nanophosphors were successfully synthesized by high-temperature fuel combustion at 1000°C for 2 h.The effects of dopant concentration on the structure and upconversion properties were investigated by X-ray diffraction,transmission electron microscopy and photoluminescence,respectively.XRD patterns indicate that the main phase of products belongs to cubic ZrO_2 fluorite-type structure.TEM results show that different fuels have great influence on the morphologies of dual-doped ZrO_2 samples.Under 980 nm excitation,the glycine-calcined nanophosphors show high stimulated luminescence and doped-ion concentration-depended intensities.The intensely red upconversion emissions are attributed to the fact that the dual-doped Yb^(3+)and Er^(3+)ions result in the non-radiative relaxation,energy migration,and cross relaxation.展开更多
One of the phenolic acids is 4-hydroxybenzoic acid(HBA)which takes the form of a white crystalline solid with a molecular formula of C 7H 6O 3,a melting point of 214.5℃and a molecular weight of 138.12 g·mol^(-1)...One of the phenolic acids is 4-hydroxybenzoic acid(HBA)which takes the form of a white crystalline solid with a molecular formula of C 7H 6O 3,a melting point of 214.5℃and a molecular weight of 138.12 g·mol^(-1).It soluble in polar organic solvents like acetone and alcohols,and slightly soluble in chloroform and water.The reactions between the metal ions and the HBA were carried out under specific conditions like(molar reaction was 2∶2(ligand to metal),reaction temperature was 60℃,media was neutral(pH 7),and solvent was H 2O∶MeOH(1∶1).Under these conditions,the HBA was deprotonated to form(HOC_(6)H_(4)CO^(2);L^(-)).The ligand L-was coordinated to the metal ions forming the metal complexation.The reaction of 4-hydroxybenzoic acid(HOC 6H 4CO 2H;HL)with the Ni(Ⅱ),Mn(Ⅱ)and Cu(Ⅱ)ions afford metal-complexes with gross formula of[Ni_(2)L_(2)(NO_(3))_(2)(H_(2)O)_(4)],[Mn_(2)L_(2)(NO_(3))_(2)(H_(2)O)_(4)]and[Cu_(2)L_(2)(NO_(3))_(2)(H_(2)O)_(4)],respectively.These complexes were characterized by elemental analysis(CHN),magnetic susceptibility,UV-Vis spectra,infrared(IR),and X-ray powder diffraction(XRD)techniques.The complexes of HBA are insoluble in common solvents and hence molar conductance could not be measured,but this very insolubility indicates that the complexes are neutral.Data has demonstrated that the ligand(L^(-))was coordinated to the metal ion by bidentate bridging carboxylate group(COO^(-)),with an octahedral geometry.Thus,HBA is expected to act as bidentate uninegative ions and the coordination number of the metal ions is six.XRD results showed that the complexes possess uniform and organized microstructures in the nanometer range with a main diameter in the range of 11~28 nm.展开更多
Perception of color with our eyes is one of the major sources of information that we gain from our surround-ings.The color of an object depends on which portion of light(range of wavelengths)reaches our eyes.In nature...Perception of color with our eyes is one of the major sources of information that we gain from our surround-ings.The color of an object depends on which portion of light(range of wavelengths)reaches our eyes.In nature,struc-tura1 colors are often caused by the interaction of light with dielectric structures whose dim ensions are on the order of visible-light wavelengths.For example,in beetles,the color is originated from the microstructure of the skin which is acting as scattering center;while in some butterflies,the colorful patterns are routed from the reflection from the top of the wings.Different optical interactions,including multilayer interference,light scattering and photonic crystal eflfect,give rise to selective transmission or reflection of particular light wavelengths.which leads to the generation of structural colors.W ith the consumption of dyes and pigments,recycling of colored discarded m aterials has been a very difficult issue because of the hardships in relation to the dissociation of diverse chemica1 compounds present in the colorant agents.Plasmonic colors therefore draw attention as they enable generation of vivid colors only by geometrical arrange-ment of m etals which not only eases the recycling but also enhances the chemical stability of the colors.Plasm onic colors are structural colors that originate from the interaction between light and metallic nanostructures.Rapid development in nanofabrication and characterization of plasmonic structures provides an efficient way to control light properties at subwavelength scale,which can generate plasmonic structural colors.The engineering of plasmonic colors is a promising rapidly em erging research field that could have a large technological impact.Artiflcia1 surfaces,in particular,on which the colors are generated via a resonant interaction between light and subwavelength metallic nanostructures,have emerged as nanomaterials or metam aterials for the realization of structura1 colors.Here we introduce several representa-tive plasmonic nanostructures which can generate visible structural colors,including nanogratings,perforated metallic film s,metal-insulator-meta1 resonators,dynamically tunable color generators and perfect absorbers.w e highlight the properties of plasmonic colors and discuss the intrinsic plasmonic resonance m echanism s.Plasmonic structural colors have features of sub-diffraction localization,high-fidelity color rendering and rapid responses of external changes,which are believed to offer a promising future in the applications including ultra-high resolution color displaB spectral filtering and sensing,holography,three-dimensiona1 stereoscopic imaging and real-time colors controlling with extremely com-pact device architectures.展开更多
文摘The current work is an extension of the nonlocal elasticity theory to fractional order thermo-elasticity in semiconducting nanostructure medium with voids.The analysis is made on the reflection phenomena in context of three-phase-lag thermo-elastic model.It is observed that,four-coupled longitudinal waves and an independent shear vertical wave exist in the medium which is dispersive in nature.It is seen that longitudinal waves are damped,and shear wave is un-damped when angular frequency is less than the cut-off frequency.The voids,thermal and non-local parameter affect the dilatational waves whereas shear wave is only depending upon non-local parameter.It is found that reflection coefficients are affected by nonlocal and fractional order parameters.Reflection coefficients are calculated analytically and computed numerically for a material,silicon and discussed graphically in details.The results for local(classical)theory are obtained as a special case.The study may be useful in semiconductor nanostructure,geology and seismology in addition to semiconductor nanostructure devices.
基金The authors would like to thank National Natural Science Foundation of China (No. 50375015) for supporting.
文摘Nanostructured FeS-SiC coating was deposited by atmospheric plasma spraying（APS）.The microstructure and phase composition of the coating were characterized with SEM and XRD,respectively.In addition,the size distribution of the reconstituted powders and the porosity of the coating have been measured.It was found that the reconstitiuted powers with sizes in the range of 20 to 80 μm had excellent flowability and were suitable for plasma spraying process.The as-sprayed FeS-SiC composite coating exhibited a bimodal distribution with small grains（30～80nm） and large grains（100～200nm）.The coating was mainly composed of FeS and SiC,a small quantity of Fe1-xS and oxide were also found.The porosity of the coating was approximately 19%.
基金Project(51676167)supported by the National Natural Science Foundation of ChinaProject(17TD0035)supported by the Sichuan Provincial Scientific Research Innovation Team Program,ChinaProjects(2017TD0026,2015TD0021)supported by Science&Technology Department of Sichuan Province,China。
文摘Diesel soot subjected to high exhaust temperature suffers from thermal ageing,which is difficult to be removed by regeneration process.Based on the thermogravimetric(TG)analysis and images by high resolution transmission electron microscope(HRTEM),effects of thermal ageing temperature,ageing time and oxygen concentration on oxidation characteristic of soot are investigated.The activation energy of soot increases with the increase of ageing temperature and oxygen concentration.The activation energy increases rapidly when the ageing time is less than 45 min,and then it keeps in a value of 157 kJ/mol when the ageing time is between 45 and 60 min.Compared to the soot without thermal ageing,the shape of ageing soot particles presents shorter diameter and more regular circle by observing soot nanostructure.With the increase of ageing temperature,ageing time and oxygen concentration,the more stable structure of“shell and core”is shown in the basic carbon.The soot has an increased fringe length,decreased tortuosity and separation distance after thermal ageing process,which leads to the deepening of the disorder degree of soot nanostructures and reduction of soot oxidation activity.Consequently,the thermal ageing process should be avoided in order to optimize the active regeneration strategy.
文摘Nanostructured n-Al2O3/Ni feedstock for thermal spraying was manufactured by the method of chemical wrapping and spray drying. The nanostructured coating was sprayed with this feedstock. Tribological properties of the coatings and steel 45# were tested. Within the testing range, the friction coefficient of coatings against GCr15 steel decreased and the mass loss of coatings increased at first then decreased with the increase of load. Under each load, the coatings’ friction coefficients and wear losses were lower than that of steel 45#. Scanning electron microscopy and energy dispersive spectrometer analysis show that adhesion is the dominating wear mechanism, and fatigue exists at the same time. Material transferred from counter-part to the coating is the main factor which influences the coatings’ friction coefficient and wear losses.
文摘A nanocomposite of manganese dioxide coated manganese hexacyanoferrate was synthesized by a facile co-precipitation method and tested as active electrode material for an electrochemical supercapacitor. A way called "Deep electro-oxidation" was used to generate manganese dioxide coated layer for stabilizing the electrode material. The structure and ingredient of the resulting MnHCF/MnO2 composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray Photoelectron Spectroscopy. Electrochemical testing showed a capacitance of 225.6 F/g at a sweep rate of 5 mV/s within a voltage range of 1.3 V, and high energy density of 37.2 Wh/kg at a current density of 0.5 A/g in galvanostatic charge/discharge cycling. It is suggested that the two different components, manganese hexacyanoferrate core and manganese dioxide shell, lead to an integrated electrochemical behavior, and an enhanced capacitor. The electrochemical testing and corresponding XPS analysis also demonstrated that the manganese coordinated by cyanide groups via nitrogen atoms in MnHCF did not get involved in the charge storage process during potential cycles.
文摘In this Study,Cadmium Oxide(CdO)nanostructures were synthesized by using Chemical Bath Deposition Technique.The synthesized process was carried out at room temperature.The structural and optical properties of nanostructures was characterized by XRD,SEM and UV-Vis techniques.As a result,the CdO nanostructures are oriented along(111)plane of cubic crystal structure.The morphology of CdO nanostructures showed interconnected prism-like and cauliflower-type cluster nanostructure.The UV results of this structures with high absorbtion coefficient are observed to be in accordance with the CdO nanoparticles.
文摘Metallic nanostructures can support the strongly confined interface waves:surface plasmon polaritons(SPPs).SPPs have recently been used in a variety of applications due to their abilities to guide light in the scale of na-nometer.Whereas,intrinsic weak optical nonlinearities and short propagation lengths of SPPs hinder their applica-tions in novel active plasmonic devices.One promising solution is to couple SPPs to nonlinear optical resonances,such as excitons(Xs)in molecular or semiconducting nanostructures.Consequently,hybrid nanostructures containing J-aggregate molecules and metallic nanostructures have attracted considerable interest.In these systems,vacuum field fluctuations lead to a coherent ex-change of energy between ensembles of excitons and plasmons and the formation of new hybrid polariton states.Strong coupling between Xs and SPPs enables an efficient transfer of the strong optical nonlinearities of the excitonic emitters to the passive plasmonic nanostructures on the ultrashort time scale of femtosecond.
文摘Hard carbons(HCs)are recognized as potential anode materials for sodium-ion batteries(SIBs)because of their low cost,environmental friendliness,and the abundance of their precursors.The presence of graphitic domains,numerous pores,and disordered carbon layers in HCs plays a significant role in determining their sodium storage ability,but these structural features depend on the precursor used.The influence of functional groups,including heteroatoms and oxygen-containing groups,and the microstructure of the precursor on the physical and electrochemical properties of the HC produced are evaluated,and the effects of carbonization conditions(carbonization temperature,heating rate and atmosphere)are also discussed.
文摘La2Zr2O7 （LZ） is a promising thermal barrier coating material for the high temperature applications. The fracture toughness and microhardness of nanocrystalline LZ （n-LZ）, microcrystalline LZ （m-LZ） and LZ-5mol%8YSZ （LZ-5-8YSZ） composite （8YSZ for zirconia stabilized by 8 mol% ytrria） were studied. The n-LZ had a thermal expansion coefficient of （9.6±0.4）×10 -6 K -1 （200～1000℃） and fracture toughness of （1.98±0.07） MPa·m 1/2 which are obviously higher than those of the m-LZ （ （9.1±0.4）×10 -6 K -1 and （1.40±0.23） MPa·m 1/2, respectively）, indicating that nanofication was an efficient way to increase the toughness and thermal expansion coefficient of LZ. The composite LZ-5-8YSZ had a higher fracture toughness （（1.88±0.30） MPa·m 1/2） than LZ, which was close to that of 8YSZ densified by superhigh pressure （SHP）.
基金financial support from A*STAR,SERC 2014 Public Sector Research Funding (PSF) Grant (SERC Project No. 1421200080)
文摘Surface enhanced Raman scattering(SERS)is an efficient technique to detect low concentration molecules.In this work,periodical silicon nanowires(Si NWs)integrated with metal-insulator-metal(MIM)layers are employed as SERS substrates.Laser interference lithography(LIL)combined with reactive ion etching(RIE)is used to fabricate large-area periodic nanostructures,followed by decorating the MIM layers.Compared to MIM disks array on Si surface,the SERS enhancement factor(EF)of the MIM structures on the Si NWs array can be increased up to 5 times,which is attributed to the enhanced electric field at the boundary of the MIM disks.Furthermore,high density of nanoparticles and nanogaps serving as hot spots on sidewall surfaces also contribute to the enhanced SERS signals.Via changing the thickness of the insulator layer,the plasmonic resonance can be tuned,which provides a new localized surface plasmon resonance(LSPR)characteristic for SERS applications.
基金Project(JCYJ20170817110251498)supported by the Basic Research Project of the Science and Technology Innovation Commission of Shenzhen,ChinaProject(2016TQ03C919)supported by the Guangdong Special Support for the Science and Technology Leading Young Scientist,ChinaProject(21603094)supported by the National Natural Science Foundation of China
文摘Developing high-performance lithium ion batteries(LIBs)using manganese oxides as anodes is attractive due to their high theoretical capacity and abundant resources.Herein,we report a facile synthesis of hierarchical spherical MnO2 containing coherent amorphous/crystalline domained by a simple yet effective redox precipitation reaction at room temperature.Further,flower-like CoMn2O4 constructed by single-crystalline spinel nanosheets has been fabricated using MnO2 as precursor.This mild methodology avoids undesired particle aggregation and loss of active surface area in conventional hydrothermal or solid-state processes.Moreover,both MnO2 and CoMn2O4 nanosheets manifest superior lithium-ion storage properties,rendering them promising applications in LIBs and other energy-related fields.
基金Project(51202066)supported by the National Natural Science Foundation of ChinaProject(NCET-13-0784)supported by the Program for New Century Excellent Talents in University of China。
文摘Hollow-structured Cu_(0.3)Co_(2.7)O_(4) microspheres have been synthesized by a simple one-pot template-free hydrothermal method with copper sulfate,cobalt acetate and ammonia as raw materials.The products were characterized by powder X-ray diffraction,energy dispersive X-ray analysis,selected area electron diffraction,high-resolution transmission electron microscopy,scanning electron microscopy and BET measurements.The research results show that the hollow Cu_(0.3)Co_(2.7)O_(4) microspheres consist of single-crystalline nanocubes with the diameter of about 20 nm.The formation mechanism of hollow Cu_(0.3)Co_(2.7)O_(4) microspheres is suggested as Ostwald ripening in a solid-solution-solid process,and Cu_(0.3)Co_(2.7)O_(4) microspheres are mesoporous containing two pore sizes of 3.3 and 5.9 nm.The as-prepared Cu_(0.3)Co_(2.7)O_(4) sensors have optimal gas responses to 50×10^(−6) mg/m^(3) C_(2)H_(5)OH at 190℃.
基金Projects(51062004,11464017)supported by the National Natural Science Foundation of ChinaProject(GJJ150671)supported by the Scientific Research Foundation for Universities from Education Bureau of Jiangxi Province,China+1 种基金Project(20161BAB216123)supported by the Natural Science Foundation of Jiangxi Province,ChinaProjects(NSFJ2014-G13,Jxxjbs12005)supported by the Jiangxi University of Science and Technology,China
文摘Ytterbia and erbia dual-doped zirconia(ZrO_2:Yb^(3+),Er^(3+))nanophosphors were successfully synthesized by high-temperature fuel combustion at 1000°C for 2 h.The effects of dopant concentration on the structure and upconversion properties were investigated by X-ray diffraction,transmission electron microscopy and photoluminescence,respectively.XRD patterns indicate that the main phase of products belongs to cubic ZrO_2 fluorite-type structure.TEM results show that different fuels have great influence on the morphologies of dual-doped ZrO_2 samples.Under 980 nm excitation,the glycine-calcined nanophosphors show high stimulated luminescence and doped-ion concentration-depended intensities.The intensely red upconversion emissions are attributed to the fact that the dual-doped Yb^(3+)and Er^(3+)ions result in the non-radiative relaxation,energy migration,and cross relaxation.
基金the deanship of scientific Research at Princess Nourah bint Abdulrahman University through the Fast-track Research Funding program。
文摘One of the phenolic acids is 4-hydroxybenzoic acid(HBA)which takes the form of a white crystalline solid with a molecular formula of C 7H 6O 3,a melting point of 214.5℃and a molecular weight of 138.12 g·mol^(-1).It soluble in polar organic solvents like acetone and alcohols,and slightly soluble in chloroform and water.The reactions between the metal ions and the HBA were carried out under specific conditions like(molar reaction was 2∶2(ligand to metal),reaction temperature was 60℃,media was neutral(pH 7),and solvent was H 2O∶MeOH(1∶1).Under these conditions,the HBA was deprotonated to form(HOC_(6)H_(4)CO^(2);L^(-)).The ligand L-was coordinated to the metal ions forming the metal complexation.The reaction of 4-hydroxybenzoic acid(HOC 6H 4CO 2H;HL)with the Ni(Ⅱ),Mn(Ⅱ)and Cu(Ⅱ)ions afford metal-complexes with gross formula of[Ni_(2)L_(2)(NO_(3))_(2)(H_(2)O)_(4)],[Mn_(2)L_(2)(NO_(3))_(2)(H_(2)O)_(4)]and[Cu_(2)L_(2)(NO_(3))_(2)(H_(2)O)_(4)],respectively.These complexes were characterized by elemental analysis(CHN),magnetic susceptibility,UV-Vis spectra,infrared(IR),and X-ray powder diffraction(XRD)techniques.The complexes of HBA are insoluble in common solvents and hence molar conductance could not be measured,but this very insolubility indicates that the complexes are neutral.Data has demonstrated that the ligand(L^(-))was coordinated to the metal ion by bidentate bridging carboxylate group(COO^(-)),with an octahedral geometry.Thus,HBA is expected to act as bidentate uninegative ions and the coordination number of the metal ions is six.XRD results showed that the complexes possess uniform and organized microstructures in the nanometer range with a main diameter in the range of 11~28 nm.
文摘Perception of color with our eyes is one of the major sources of information that we gain from our surround-ings.The color of an object depends on which portion of light(range of wavelengths)reaches our eyes.In nature,struc-tura1 colors are often caused by the interaction of light with dielectric structures whose dim ensions are on the order of visible-light wavelengths.For example,in beetles,the color is originated from the microstructure of the skin which is acting as scattering center;while in some butterflies,the colorful patterns are routed from the reflection from the top of the wings.Different optical interactions,including multilayer interference,light scattering and photonic crystal eflfect,give rise to selective transmission or reflection of particular light wavelengths.which leads to the generation of structural colors.W ith the consumption of dyes and pigments,recycling of colored discarded m aterials has been a very difficult issue because of the hardships in relation to the dissociation of diverse chemica1 compounds present in the colorant agents.Plasmonic colors therefore draw attention as they enable generation of vivid colors only by geometrical arrange-ment of m etals which not only eases the recycling but also enhances the chemical stability of the colors.Plasm onic colors are structural colors that originate from the interaction between light and metallic nanostructures.Rapid development in nanofabrication and characterization of plasmonic structures provides an efficient way to control light properties at subwavelength scale,which can generate plasmonic structural colors.The engineering of plasmonic colors is a promising rapidly em erging research field that could have a large technological impact.Artiflcia1 surfaces,in particular,on which the colors are generated via a resonant interaction between light and subwavelength metallic nanostructures,have emerged as nanomaterials or metam aterials for the realization of structura1 colors.Here we introduce several representa-tive plasmonic nanostructures which can generate visible structural colors,including nanogratings,perforated metallic film s,metal-insulator-meta1 resonators,dynamically tunable color generators and perfect absorbers.w e highlight the properties of plasmonic colors and discuss the intrinsic plasmonic resonance m echanism s.Plasmonic structural colors have features of sub-diffraction localization,high-fidelity color rendering and rapid responses of external changes,which are believed to offer a promising future in the applications including ultra-high resolution color displaB spectral filtering and sensing,holography,three-dimensiona1 stereoscopic imaging and real-time colors controlling with extremely com-pact device architectures.
