A brief introduction of the connotation and characteristics of metal functional materials was presented. The current research and development of several important materials and the difference between home and world ad...A brief introduction of the connotation and characteristics of metal functional materials was presented. The current research and development of several important materials and the difference between home and world advanced level were described. The latest trend of research and development was discussed. The industrialization and market for several new metal functional materials were commented and some opinions also were given.展开更多
A nonlinear finite element method is applied to observe how inclusion shape influence the thermal response of a ceramic-metal functionally graded material (FGM). The elastic and plastic behaviors of the layers which a...A nonlinear finite element method is applied to observe how inclusion shape influence the thermal response of a ceramic-metal functionally graded material (FGM). The elastic and plastic behaviors of the layers which are two-phase isotropic composites consisting of randomly oriented elastic spheroidal Inclusions and a ductile matrix are predicted by cc mean field method. The prediction results show that inclusion shape has remarkable influence on the overall behavior of the composite. The consequences of the thermal response analysis of the FGM are that the response is dependent on inclusion shape and its composition profile cooperatively and that the plastic behavior of each layer should be taken into account in optimum design of a ceramic-metal FGM.展开更多
Based on the three-component assumption that the reflection is divided into specular reflection,directional diffuse reflection,and ideal diffuse reflection,a bidirectional reflectance distribution function（BRDF） mod...Based on the three-component assumption that the reflection is divided into specular reflection,directional diffuse reflection,and ideal diffuse reflection,a bidirectional reflectance distribution function（BRDF） model of metallic materials is presented.Compared with the two-component assumption that the reflection is composed of specular reflection and diffuse reflection,the three-component assumption divides the diffuse reflection into directional diffuse and ideal diffuse reflection.This model effectively resolves the problem that constant diffuse reflection leads to considerable error for metallic materials.Simulation and measurement results validate that this three-component BRDF model can improve the modeling accuracy significantly and describe the reflection properties in the hemisphere space precisely for the metallic materials.展开更多
Surface functionalization of suspended single-walled carbon nanotubes(SWNTs) using metal(Au) nanoparticles(NPs) is reported.SWNTs are grown on three-dimensionally patterned substrates by thermal chemical vapor deposit...Surface functionalization of suspended single-walled carbon nanotubes(SWNTs) using metal(Au) nanoparticles(NPs) is reported.SWNTs are grown on three-dimensionally patterned substrates by thermal chemical vapor deposition and successfully functionalized with Au NPs.Ethylendiamine is mainly used to functionalize SWNTs surface with amino groups before introducing Au NPs.From Raman scattering spectroscopy of the Au-functionalized suspended SWNTs,enhanced Raman scattering properties are obtained.The results suggest that the attached Au NPs may contribute to the enhancement of resonant phenomena.By measuring the electric properties after each functionalization process,it is found that Au NPs act as electron acceptor to the amine functionalized SWNTs.展开更多
Metal-organic frameworks（MOFs） are a unique class of porous crystalline materials that have shown promise for a wide range of applications. MOFs have been explored as a new type of heterogeneous catalytic materials,...Metal-organic frameworks（MOFs） are a unique class of porous crystalline materials that have shown promise for a wide range of applications. MOFs have been explored as a new type of heterogeneous catalytic materials, because of their high surface area, uniform and tunable pores, facile functionalization and incorporation of catalytic active sites. The use of multi-functional sites MOF materials as catalysts for synergistic catalysis and tandem reactions has attracted increasing attention. In this review, we aim to introduce the construction of bi-or multi-functional MOF catalysts with cooperative or cascade functions via post-synthetic modification（PSM）.展开更多
This paper uses the generalised gradient approximation based on density functional theory to analyse the geometric structure and properties of the 3d transition metal atom doped endohedral fullerene M@C20F20 （M = Sc...This paper uses the generalised gradient approximation based on density functional theory to analyse the geometric structure and properties of the 3d transition metal atom doped endohedral fullerene M@C20F20 （M = Sc-Ni）. The geometric optimization shows that the cage centre is the most stable position for M, forming the structure named as M@C20F20-4. The inclusion energy, zero-point energy, and energy gap calculations tell us that Ni@C20F20-4 should be thermodynamically and kinetically stablest. M@C20F20-4 （M = Sc-Co） possesses high magnetic moments varied from 1 to 6 μB, while Ni@C20F20-4 is nonmagnetic. The Ni-C bond in Ni@C20F20-4 contains both the covalent and ionic characters.展开更多
The biosynthesis strategy of nanoparticles has attracted much attention due to the mild synthesis condi-tions,environmental-friendly properties,and low costs.Biosynthesized nanoparticles(bio-NPs)not only show excellen...The biosynthesis strategy of nanoparticles has attracted much attention due to the mild synthesis condi-tions,environmental-friendly properties,and low costs.Biosynthesized nanoparticles(bio-NPs)not only show excellent physicochemical properties,but also exhibit high stability,enlarged specific surface area,and excellent biocompatibility,which are crucial for industrial,agricultural,and medical fields.She-wanella,a kind of dissimilatory metal-reducing bacteria,is regarded as a typical biosynthesis-functional bacteria class with wide distribution and strong adaptability.Thus,in this paper,functional bio-NPs by Shewanella were reviewed to provide a comprehensive view of current research progress.The biosynthetic mechanisms of Shewanella are summarized as the Mtr pathway(predominant),extracellular polymeric substance-induced pathway,and enzyme/protein-induced pathway.During the biosynthesis process,bio-logical factors along with the physicochemical parameters highly influenced the properties of the resul-tant bio-NPs.Till now,bio-NPs have been applied in various fields including environmental remediation,antibacterial applications,and microbial fuel cells.However,some challenging issues of bio-NPs by She-wanella remain unsolved,such as optimizing suitable bacterial strains,intelligently controlling bio-NPs,clarifying biosynthesis mechanisms,and expanding bio-NPs applications.展开更多
Late-stage modification of peptides and proteins meets the increasing demand in biochemical and pharmaceutical communities. These modification strategies could provide functionalized nonproteinogenic analogues with en...Late-stage modification of peptides and proteins meets the increasing demand in biochemical and pharmaceutical communities. These modification strategies could provide functionalized nonproteinogenic analogues with enhanced biological activities or improved therapeutic capabilities compared to their natural counterparts. Recent years, transition-metal-promoted functionalization of ubiquitous C-H bonds has been emerged as a powerful and tunable tool in this area, both for backbone diversifications and labeling of specific moieties. These reactions were flexible and expedient in both academic and industrial laboratories, especially considering their atom and step-economy, good functional group compatibility, accurate site selectivity. This review surveys the progress achieved in the late-stage modification of peptides and proteins utilizing transition-metal-catalyzed C-H functionalization with C-C and C-X(F, Cl, O, N, B, etc.) bonds formation.展开更多
Multivariate metal-organic frameworks（MTV-MOFs） with different ratios of terephthalate（BDC） linker and amino-benzenedicarboxylate（BDC-NH2） linker were synthesized through both direct synthesis from linker mixtur...Multivariate metal-organic frameworks（MTV-MOFs） with different ratios of terephthalate（BDC） linker and amino-benzenedicarboxylate（BDC-NH2） linker were synthesized through both direct synthesis from linker mixture and linker exchange of activated single-linker MOFs. Functionality proportion was impacted by the thermodynamics during the one-pot MOF construction, resulting in preference of BDC over BDC-NH2 in the MTV-MOF, in agreement with the quantum mechanics calculations. The functionality difference also affects the thermodynamics in the linker exchange process, as indicated by the more effective linker exchange in BDC-NH2-based IRMOF-3 than in BDC-based MOF-5. Furthermore,the thermal decomposition temperatures and chemical integrity upon ambient air exposure of these MOFs with variate functionalities were investigated, and it reveals that higher proportion of BDC in the MTV-MOF crystals contribute to both higher thermal and higher chemical stabilities.展开更多
The adsorption of cyanide on the top site of a series of transition metal M（100） （M = Cu, Ag, Au, Ni, Pd, Pt） surfaces via carbon and nitrogen atoms respectively, with the CN axis perpendicular to the surface, has...The adsorption of cyanide on the top site of a series of transition metal M（100） （M = Cu, Ag, Au, Ni, Pd, Pt） surfaces via carbon and nitrogen atoms respectively, with the CN axis perpendicular to the surface, has been studied by means of density functional theory and cluster model. Geometry, adsorption energy and vibrational frequencies have been determined, and the present calculations show that the adsorption of CN through C-end on metal surface is more favorable than that via N-end for the same surface. The vibrational frequencies of CN for C-down configuration on surface are blue-shifted with respect to the free CN, which is contrary to the change of vibrational frequencies when CN is adsorbed by N-down structure. Furthermore, the charge transfer from surface to CN causes the increase of surface work function.展开更多
The geometric structures, electronic and magnetic properties of the 3d transition metal doped clusters Pd12M （M = Sc-Ni） are studied using the semi^core pseudopots density functional theory. The groundstate geometri...The geometric structures, electronic and magnetic properties of the 3d transition metal doped clusters Pd12M （M = Sc-Ni） are studied using the semi^core pseudopots density functional theory. The groundstate geometric structure of the Pd12M cluster is probably of pseudoicosahedron. The Ih-Pd12M cluster has the most thermodynamic stability in five different symmetric isomers. The energy gap shows that Pd12M cluster is partly metallic. Both the absolutely predominant metal bond and very weak covalent bond might exist in the Pdl2M cluster. The magnetic mo- ment of Pd12M varies from 0 to 5 μB, implying that it has a potential application in new nanomaterials with tunable magnetic properties.展开更多
Copolyesters having secondary and tertiary amine salt groups in the main and side chains are prepared by chemoselective polymerization. These copolyesters are soluble in a 10% aqueous solution of poly(vinyl alcohol) ...Copolyesters having secondary and tertiary amine salt groups in the main and side chains are prepared by chemoselective polymerization. These copolyesters are soluble in a 10% aqueous solution of poly(vinyl alcohol) (PVA) at 90 degree C and act as plasticizer in the blend films cast from the solution. Only a glass transition temperature is observed for all these blends indicating the formation of compatible blends from these polyesters with PVA. These blends exhibit manifold characteristics such as ionic conductivity, complex formation with metal ions, absorption of moisture and color changes. The electric conductivity of the copolyesters and blends is in the range of 10** minus **6 Scm** minus **1. The blends with PVA forms complexes with Cu**2** plus and Co**2** plus . The coordination structure with two chelate rings is suggested for these polymer blend/metal complexes. (Author abstract) 10 Refs.展开更多
Background: There is much interest regarding metal-on-metal implants in medical and general media. Much of this has been regarding failure of specific implant systems and metal ion toxicity. We present our early mid-t...Background: There is much interest regarding metal-on-metal implants in medical and general media. Much of this has been regarding failure of specific implant systems and metal ion toxicity. We present our early mid-term experience of the ADEPT metal-on-metal system which has both modular and non-modular hip options. Methods: Functional assessment, blood metal ion quantification, and radiographic analysis were performed for the modular and non-modular ADEPT variants. Fifty implants were implanted with a mean follow up time of 28 months. Unpaired t-tests were used to compare modular and resurfacing groups, standardised hip scores were used to compare function to conventional total hip arthroplasty. Results: Metal ion levels were significantly higher in modular prostheses compared to resurfacing implants, but not at “harmful” levels (as determined by a previous metal-on-metal implant recall). Functional outcomes were excellent and revision rates were lower than expected. Conclusions: At our institution we have good outcomes with the ADEPT hip prosthesis. Though patient selection and implant position are crucial, poor performance of metal-on-metal hip replacements is implant specific.展开更多
An expression of degree of polarization（DOP） for metallic material is presented based on the three-component polarized bidirectional reflectance distribution function（p BRDF） model with considering specular reflec...An expression of degree of polarization（DOP） for metallic material is presented based on the three-component polarized bidirectional reflectance distribution function（p BRDF） model with considering specular reflection, directional diffuse reflection and ideal diffuse reflection. The three-component p BRDF model with a detailed reflection assumption is validated by comparing simulations with measurements. The DOP expression presented in this paper is related to surface roughness, which makes it more reasonable in physics. Test results for two metallic samples show that the DOP based on the three-component p BRDF model accords well with the measurement and the error of existing DOP expression is significantly reduced by introducing the diffuse reflection. It indicates that our DOP expression describes the polarized reflection properties of metallic surfaces more accurately.展开更多
One-dimensional Cr2NO2 nanoribbons cut from the oxygen-passivated Cr2NO2 MXene were investigated by using density functional theory. The wide nanoribbons have ferromagnetic ground states and are intrinsic half-metals,...One-dimensional Cr2NO2 nanoribbons cut from the oxygen-passivated Cr2NO2 MXene were investigated by using density functional theory. The wide nanoribbons have ferromagnetic ground states and are intrinsic half-metals, independent of their chirality. The half-metallic band gaps of wide nanoribbons are larger than 1 eV, which are large enough for avoiding thermally activated spin flip. The magnetism does not rely on the edge states but originates from all the Cr atoms. Furthermore, the half-metallicity is still robust in an electronic device even if the bias is up to 1 V. Therefore, one-dimensional Cr2NO2 nanoribbons are good candidates for spintronics.展开更多
In this study, friction stir processing（FSP） was employed to modify cold-sprayed（CSed） AA2024/Al2 O3 metal matrix composites（MMCs）. Three different rotation speeds with a constant traverse speed were used for FS...In this study, friction stir processing（FSP） was employed to modify cold-sprayed（CSed） AA2024/Al2 O3 metal matrix composites（MMCs）. Three different rotation speeds with a constant traverse speed were used for FSP. Microstructural analysis of the FSPed specimens reveals significant Al2 O3 particle refinement and improved particle distribution over the as-sprayed deposits. After FSP, a microstructural and mechanical gradient MMC through the thickness direction was obtained. Therefore, a hybrid technique combining these two solid-state processes, i.e. CS and FSP, was proposed to produce functionally gradient deposits. The Guinier-Preston-Bagaryatskii zone was dissolved during FSP, while the amounts at different rotation speeds were approximately the same, which is possibly due to the excellent thermal conductivity of the used Cu substrate. Mechanical property tests confirm that FSP can effectively improve the tensile performance and Vickers hardness of CSed AA2024/Al2 O3 MMCs. The properties can be further enhanced with a larger rotation speed with a maximum increase of 25.9% in ultimate tensile strength and27.4% in elongation at 1500 rpm. Friction tests show that FSP decreases the wear resistance of CSed MMCs deposits due to the breakup of Al2 O3 particles. The average values and fluctuations of friction coefficients at different rotation speeds vary significantly.展开更多
Amino-functionalized Fe3O4@mesoporous SiO/ core-shell composite microspheres NH2-MS in created in multiple synthesis steps have been investigated for Pb（Ⅱ） and Cd（Ⅱ） adsorption. The microspheres were characteriz...Amino-functionalized Fe3O4@mesoporous SiO/ core-shell composite microspheres NH2-MS in created in multiple synthesis steps have been investigated for Pb（Ⅱ） and Cd（Ⅱ） adsorption. The microspheres were characterized by transmission electron microscope （TEM）, scanning electron microscope （SEM）, N2 adsorption-desorption, zeta potential measurements and vibrating sample magnetometer. Batch adsorption tests indicated that NH2-MS exhibited higher adsorption affinity toward Pb（Ⅱ） and Cd（Ⅱ） than MS did. The Langmuir model could fit the adsorption isotherm very well with maximum adsorption capacity of 128.21 and 51.81 mg/g for Pb（Ⅱ） and Cd（Ⅱ）, respectively, implying that adsorption processes involved monolayer adsorption. Pb（Ⅱ） and Cd（Ⅱ） adsorption could be well described by the pseudo second-order kinetics model, and was found to be strongly dependent on pH and humic acid. The Pb（Ⅱ）- and Cd（Ⅱ）-loaded microspheres were effectively desorbed using 0.01 mol/L HC1 or EDTA solution. NH2-MS have promise for use as adsorbents in the removal of Pb（Ⅱ） and Cd（Ⅱ） in wastewater treatment processes.展开更多
文摘A brief introduction of the connotation and characteristics of metal functional materials was presented. The current research and development of several important materials and the difference between home and world advanced level were described. The latest trend of research and development was discussed. The industrialization and market for several new metal functional materials were commented and some opinions also were given.
基金Funded by National Science Foundation of China(Grant:1987205).
文摘A nonlinear finite element method is applied to observe how inclusion shape influence the thermal response of a ceramic-metal functionally graded material (FGM). The elastic and plastic behaviors of the layers which are two-phase isotropic composites consisting of randomly oriented elastic spheroidal Inclusions and a ductile matrix are predicted by cc mean field method. The prediction results show that inclusion shape has remarkable influence on the overall behavior of the composite. The consequences of the thermal response analysis of the FGM are that the response is dependent on inclusion shape and its composition profile cooperatively and that the plastic behavior of each layer should be taken into account in optimum design of a ceramic-metal FGM.
文摘Based on the three-component assumption that the reflection is divided into specular reflection,directional diffuse reflection,and ideal diffuse reflection,a bidirectional reflectance distribution function（BRDF） model of metallic materials is presented.Compared with the two-component assumption that the reflection is composed of specular reflection and diffuse reflection,the three-component assumption divides the diffuse reflection into directional diffuse and ideal diffuse reflection.This model effectively resolves the problem that constant diffuse reflection leads to considerable error for metallic materials.Simulation and measurement results validate that this three-component BRDF model can improve the modeling accuracy significantly and describe the reflection properties in the hemisphere space precisely for the metallic materials.
基金supported by 2008 Research Grant from Kangwon National University,Korea
文摘Surface functionalization of suspended single-walled carbon nanotubes(SWNTs) using metal(Au) nanoparticles(NPs) is reported.SWNTs are grown on three-dimensionally patterned substrates by thermal chemical vapor deposition and successfully functionalized with Au NPs.Ethylendiamine is mainly used to functionalize SWNTs surface with amino groups before introducing Au NPs.From Raman scattering spectroscopy of the Au-functionalized suspended SWNTs,enhanced Raman scattering properties are obtained.The results suggest that the attached Au NPs may contribute to the enhancement of resonant phenomena.By measuring the electric properties after each functionalization process,it is found that Au NPs act as electron acceptor to the amine functionalized SWNTs.
基金supported by the National Natural Science Foundation of China (Nos. 21371069 and 21621001)
文摘Metal-organic frameworks（MOFs） are a unique class of porous crystalline materials that have shown promise for a wide range of applications. MOFs have been explored as a new type of heterogeneous catalytic materials, because of their high surface area, uniform and tunable pores, facile functionalization and incorporation of catalytic active sites. The use of multi-functional sites MOF materials as catalysts for synergistic catalysis and tandem reactions has attracted increasing attention. In this review, we aim to introduce the construction of bi-or multi-functional MOF catalysts with cooperative or cascade functions via post-synthetic modification（PSM）.
基金Project supported by the Research Starting Foundation of Hohai University (Grant No. 2084/40801130)the Natural Science Foundation of Hohai University (Grant Nos. 2008431211 and 2008430311)+2 种基金the Excellent Innovation Personal Support Plan of Hohai Universitythe Basic Scientific Research Foundation of National Centralthe Special Foundation of the Natural Natural Science (Grant No. 10947132)
文摘This paper uses the generalised gradient approximation based on density functional theory to analyse the geometric structure and properties of the 3d transition metal atom doped endohedral fullerene M@C20F20 （M = Sc-Ni）. The geometric optimization shows that the cage centre is the most stable position for M, forming the structure named as M@C20F20-4. The inclusion energy, zero-point energy, and energy gap calculations tell us that Ni@C20F20-4 should be thermodynamically and kinetically stablest. M@C20F20-4 （M = Sc-Co） possesses high magnetic moments varied from 1 to 6 μB, while Ni@C20F20-4 is nonmagnetic. The Ni-C bond in Ni@C20F20-4 contains both the covalent and ionic characters.
基金supported by the Hainan Provincial Joint Project of Sanya Yazhou Bay Science and Technology City(no.2021CXLH0005)the National Key Research and Development Pro-gram of China(no.2022YFC3106004)+5 种基金Shandong Provincial Natu-ral Science Foundation of China(no.ZR2022MD023)the Young Elite Scientists Sponsorship Program by CAST(no.YESS20210201)Wenhai Program of the S&T Fund of Shandong Province for Pi-lot National Laboratory for Marine Science and Technology(Qing-dao)(no.2021WHZZB2303)the Basic Scientific Fund for Na-tional Public Research Institutes of China(nos.2019Y03 and 2020S02)Hainan Province Science and Technology Special Fund(no.ZDYF2021GXJS210)National Natural Science Foundation of China(no.41706080).
文摘The biosynthesis strategy of nanoparticles has attracted much attention due to the mild synthesis condi-tions,environmental-friendly properties,and low costs.Biosynthesized nanoparticles(bio-NPs)not only show excellent physicochemical properties,but also exhibit high stability,enlarged specific surface area,and excellent biocompatibility,which are crucial for industrial,agricultural,and medical fields.She-wanella,a kind of dissimilatory metal-reducing bacteria,is regarded as a typical biosynthesis-functional bacteria class with wide distribution and strong adaptability.Thus,in this paper,functional bio-NPs by Shewanella were reviewed to provide a comprehensive view of current research progress.The biosynthetic mechanisms of Shewanella are summarized as the Mtr pathway(predominant),extracellular polymeric substance-induced pathway,and enzyme/protein-induced pathway.During the biosynthesis process,bio-logical factors along with the physicochemical parameters highly influenced the properties of the resul-tant bio-NPs.Till now,bio-NPs have been applied in various fields including environmental remediation,antibacterial applications,and microbial fuel cells.However,some challenging issues of bio-NPs by She-wanella remain unsolved,such as optimizing suitable bacterial strains,intelligently controlling bio-NPs,clarifying biosynthesis mechanisms,and expanding bio-NPs applications.
基金the support from the National Key R&D Program of China(No. 2017YFA0505400)the National Natural Science Foundation of China (Nos. 21572214, 21702200)
文摘Late-stage modification of peptides and proteins meets the increasing demand in biochemical and pharmaceutical communities. These modification strategies could provide functionalized nonproteinogenic analogues with enhanced biological activities or improved therapeutic capabilities compared to their natural counterparts. Recent years, transition-metal-promoted functionalization of ubiquitous C-H bonds has been emerged as a powerful and tunable tool in this area, both for backbone diversifications and labeling of specific moieties. These reactions were flexible and expedient in both academic and industrial laboratories, especially considering their atom and step-economy, good functional group compatibility, accurate site selectivity. This review surveys the progress achieved in the late-stage modification of peptides and proteins utilizing transition-metal-catalyzed C-H functionalization with C-C and C-X(F, Cl, O, N, B, etc.) bonds formation.
基金supported by the "Top-Notch Students Training in Basic Disciplines" undergraduate program of Ministry of Education of China
文摘Multivariate metal-organic frameworks（MTV-MOFs） with different ratios of terephthalate（BDC） linker and amino-benzenedicarboxylate（BDC-NH2） linker were synthesized through both direct synthesis from linker mixture and linker exchange of activated single-linker MOFs. Functionality proportion was impacted by the thermodynamics during the one-pot MOF construction, resulting in preference of BDC over BDC-NH2 in the MTV-MOF, in agreement with the quantum mechanics calculations. The functionality difference also affects the thermodynamics in the linker exchange process, as indicated by the more effective linker exchange in BDC-NH2-based IRMOF-3 than in BDC-based MOF-5. Furthermore,the thermal decomposition temperatures and chemical integrity upon ambient air exposure of these MOFs with variate functionalities were investigated, and it reveals that higher proportion of BDC in the MTV-MOF crystals contribute to both higher thermal and higher chemical stabilities.
基金the National Natural Science Foundation of China (20673019, 20773024)the Natural Science Foundation of Fujian Province (U0650012)the New Century Excellent Talents in University and the Initial Funding for Talents of Fuzhou University (2008-XQ-07, XRC-0732)
文摘The adsorption of cyanide on the top site of a series of transition metal M（100） （M = Cu, Ag, Au, Ni, Pd, Pt） surfaces via carbon and nitrogen atoms respectively, with the CN axis perpendicular to the surface, has been studied by means of density functional theory and cluster model. Geometry, adsorption energy and vibrational frequencies have been determined, and the present calculations show that the adsorption of CN through C-end on metal surface is more favorable than that via N-end for the same surface. The vibrational frequencies of CN for C-down configuration on surface are blue-shifted with respect to the free CN, which is contrary to the change of vibrational frequencies when CN is adsorbed by N-down structure. Furthermore, the charge transfer from surface to CN causes the increase of surface work function.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11104062,10947132,and 11004047)the Excellent Innovation Personal Support Plan of Hohai University,Chinathe Fundamental Research Funds for the Central Universities of China (Grant No. 2012B12914)
文摘The geometric structures, electronic and magnetic properties of the 3d transition metal doped clusters Pd12M （M = Sc-Ni） are studied using the semi^core pseudopots density functional theory. The groundstate geometric structure of the Pd12M cluster is probably of pseudoicosahedron. The Ih-Pd12M cluster has the most thermodynamic stability in five different symmetric isomers. The energy gap shows that Pd12M cluster is partly metallic. Both the absolutely predominant metal bond and very weak covalent bond might exist in the Pdl2M cluster. The magnetic mo- ment of Pd12M varies from 0 to 5 μB, implying that it has a potential application in new nanomaterials with tunable magnetic properties.
文摘Copolyesters having secondary and tertiary amine salt groups in the main and side chains are prepared by chemoselective polymerization. These copolyesters are soluble in a 10% aqueous solution of poly(vinyl alcohol) (PVA) at 90 degree C and act as plasticizer in the blend films cast from the solution. Only a glass transition temperature is observed for all these blends indicating the formation of compatible blends from these polyesters with PVA. These blends exhibit manifold characteristics such as ionic conductivity, complex formation with metal ions, absorption of moisture and color changes. The electric conductivity of the copolyesters and blends is in the range of 10** minus **6 Scm** minus **1. The blends with PVA forms complexes with Cu**2** plus and Co**2** plus . The coordination structure with two chelate rings is suggested for these polymer blend/metal complexes. (Author abstract) 10 Refs.
文摘Background: There is much interest regarding metal-on-metal implants in medical and general media. Much of this has been regarding failure of specific implant systems and metal ion toxicity. We present our early mid-term experience of the ADEPT metal-on-metal system which has both modular and non-modular hip options. Methods: Functional assessment, blood metal ion quantification, and radiographic analysis were performed for the modular and non-modular ADEPT variants. Fifty implants were implanted with a mean follow up time of 28 months. Unpaired t-tests were used to compare modular and resurfacing groups, standardised hip scores were used to compare function to conventional total hip arthroplasty. Results: Metal ion levels were significantly higher in modular prostheses compared to resurfacing implants, but not at “harmful” levels (as determined by a previous metal-on-metal implant recall). Functional outcomes were excellent and revision rates were lower than expected. Conclusions: At our institution we have good outcomes with the ADEPT hip prosthesis. Though patient selection and implant position are crucial, poor performance of metal-on-metal hip replacements is implant specific.
文摘An expression of degree of polarization（DOP） for metallic material is presented based on the three-component polarized bidirectional reflectance distribution function（p BRDF） model with considering specular reflection, directional diffuse reflection and ideal diffuse reflection. The three-component p BRDF model with a detailed reflection assumption is validated by comparing simulations with measurements. The DOP expression presented in this paper is related to surface roughness, which makes it more reasonable in physics. Test results for two metallic samples show that the DOP based on the three-component p BRDF model accords well with the measurement and the error of existing DOP expression is significantly reduced by introducing the diffuse reflection. It indicates that our DOP expression describes the polarized reflection properties of metallic surfaces more accurately.
基金supported by the National Natural Science Foundation of China(No.21203127)the Scientific Research Base Development Program of the Beijing Municipal Commission of Education
文摘One-dimensional Cr2NO2 nanoribbons cut from the oxygen-passivated Cr2NO2 MXene were investigated by using density functional theory. The wide nanoribbons have ferromagnetic ground states and are intrinsic half-metals, independent of their chirality. The half-metallic band gaps of wide nanoribbons are larger than 1 eV, which are large enough for avoiding thermally activated spin flip. The magnetism does not rely on the edge states but originates from all the Cr atoms. Furthermore, the half-metallicity is still robust in an electronic device even if the bias is up to 1 V. Therefore, one-dimensional Cr2NO2 nanoribbons are good candidates for spintronics.
基金financially by the National Key Research and Development Program of China (No. 2016YFB1100104)the Fund of SAST (No. SAST2016043)the 111 Project (No. B08040)
文摘In this study, friction stir processing（FSP） was employed to modify cold-sprayed（CSed） AA2024/Al2 O3 metal matrix composites（MMCs）. Three different rotation speeds with a constant traverse speed were used for FSP. Microstructural analysis of the FSPed specimens reveals significant Al2 O3 particle refinement and improved particle distribution over the as-sprayed deposits. After FSP, a microstructural and mechanical gradient MMC through the thickness direction was obtained. Therefore, a hybrid technique combining these two solid-state processes, i.e. CS and FSP, was proposed to produce functionally gradient deposits. The Guinier-Preston-Bagaryatskii zone was dissolved during FSP, while the amounts at different rotation speeds were approximately the same, which is possibly due to the excellent thermal conductivity of the used Cu substrate. Mechanical property tests confirm that FSP can effectively improve the tensile performance and Vickers hardness of CSed AA2024/Al2 O3 MMCs. The properties can be further enhanced with a larger rotation speed with a maximum increase of 25.9% in ultimate tensile strength and27.4% in elongation at 1500 rpm. Friction tests show that FSP decreases the wear resistance of CSed MMCs deposits due to the breakup of Al2 O3 particles. The average values and fluctuations of friction coefficients at different rotation speeds vary significantly.
基金supported by the National Natural Science Foundation of China (No. 21007048)the Key Projects in the National Science & Technology Pillar Program during the Twelfth Five-year Plan Period (No. 2012BAF03B06,2012BAJ25B06)partial fund of the State Key Laboratory of Pollution Control and Resource Reuse Foundation(No. PCRRY11011,PCRRF11003)
文摘Amino-functionalized Fe3O4@mesoporous SiO/ core-shell composite microspheres NH2-MS in created in multiple synthesis steps have been investigated for Pb（Ⅱ） and Cd（Ⅱ） adsorption. The microspheres were characterized by transmission electron microscope （TEM）, scanning electron microscope （SEM）, N2 adsorption-desorption, zeta potential measurements and vibrating sample magnetometer. Batch adsorption tests indicated that NH2-MS exhibited higher adsorption affinity toward Pb（Ⅱ） and Cd（Ⅱ） than MS did. The Langmuir model could fit the adsorption isotherm very well with maximum adsorption capacity of 128.21 and 51.81 mg/g for Pb（Ⅱ） and Cd（Ⅱ）, respectively, implying that adsorption processes involved monolayer adsorption. Pb（Ⅱ） and Cd（Ⅱ） adsorption could be well described by the pseudo second-order kinetics model, and was found to be strongly dependent on pH and humic acid. The Pb（Ⅱ）- and Cd（Ⅱ）-loaded microspheres were effectively desorbed using 0.01 mol/L HC1 or EDTA solution. NH2-MS have promise for use as adsorbents in the removal of Pb（Ⅱ） and Cd（Ⅱ） in wastewater treatment processes.
