A series of Cu-substituted Ni_(0.5-x)Cu_xZn_(0.5)Fe_2O_4(x=0.12,0.16,0.20,0.24 and 0.28) spinel ferrites were prepared by conventional ceramic method to investigate the effects of Cu compositional variation on the str...A series of Cu-substituted Ni_(0.5-x)Cu_xZn_(0.5)Fe_2O_4(x=0.12,0.16,0.20,0.24 and 0.28) spinel ferrites were prepared by conventional ceramic method to investigate the effects of Cu compositional variation on the structure and dielectric properties.XRD patterns demonstrate that all the samples are crystallized in single-phase cubic spinel structure and the lattice constant increases with increasing Cu content.White grains observed by SEM are Cu-rich phase.The dielectric constant versus frequency curve displays a normal dielectric behavior of spinel ferrites.While the frequency dependence of dielectric loss tangent is found to be abnormal,exhibiting a peak at certain frequency for all Cu-substituted Ni-Zn ferrites.A maximum of the resistivity is observed at x=0.2 due to the decrease of hopping electrons between Fe^(2+) and Fe^(3+) in per unit volume,which is in contrast with the Cu content dependence of dielectric constant and dielectric loss.展开更多
Highly oxidation. SEM analysis ordered anatase titania nanotube method was used to characterize arrays （TINT） were fabricated by anodic the morphology of the prepared samples. TiNT samples doped with Cu ions were pr...Highly oxidation. SEM analysis ordered anatase titania nanotube method was used to characterize arrays （TINT） were fabricated by anodic the morphology of the prepared samples. TiNT samples doped with Cu ions were prepared by home-made Metal Vapor Vacuum Arc ions sources （MEVVA, BNU, China） implanter. Photo-electric response and methyl orange decomposition ability of implanted samples under UV and visible light were tested, and the results indicated that the performance of Cu/TiNT enhanced significantly under visible light; it was noteworthy that the photocurrent density of A-Cu/TiNT was 0.102 mA/cm^2, which was 115 times that of pure TINT, and degradation ability of TiNT also strongly enhanced under visible light. In a word, the absorption spectrum of implanted anatase titania shifted to a longer wavelength region. Theoretic study on Cu-doped anatase based on density functional theory was carried out in this paper to validate the experiment results. The calculation results are depicted as follows： Intermittent energy band appeared around the Fermi energy after doping with Cu metal, the width of which was 0.35 eV and the location of valence and conduction bands shifted to the lower energy level by 0.22 eV; more excitation and jump routes were opened for the electrons. The narrowed band gaps allowed the photons with lower energy （at longer wavelength, such as visible light） to be absorbed, which accorded well with the experimental results.展开更多
Cu ion implantation and subsequent rapid annealing at 500℃ in N2 result in low surface resistivity of 1.611 ohm/sq with high mobility of 290 cm2 V-1S-1 for microcrystalline diamond （MCD） films. Its electrical field...Cu ion implantation and subsequent rapid annealing at 500℃ in N2 result in low surface resistivity of 1.611 ohm/sq with high mobility of 290 cm2 V-1S-1 for microcrystalline diamond （MCD） films. Its electrical field emission behavior can be turned on at Eo = 2.6 V/μm, attaining a current density of 19.5μA/cm2 at an applied field of 3.5 V/#m. Field emission scanning electron microscopy combined with Raman and x-ray photoelectron mi- croscopy reveal that the formation of Cu nanoparticles in MCD films can catalytically convert the less conducting disorder/a-C phases into graphitic phases and can provoke the formation of nanographite in the films, forming conduction channels for electron transportation.展开更多
Copper ions were implanted into a AISI420 martensitic stainless steel (SS) by metal vapor vacuum arc (MEVVA) with a dose range 0.2 xlO17 -S.OxlO17 cm"2 at the energy of lOOkeV. The Cu-implanted stainless steel wa...Copper ions were implanted into a AISI420 martensitic stainless steel (SS) by metal vapor vacuum arc (MEVVA) with a dose range 0.2 xlO17 -S.OxlO17 cm"2 at the energy of lOOkeV. The Cu-implanted stainless steel was treated by a special antibacterial treatment subsequently. The phase compositions in the implanted layer were studied by glancing X-ray diffraction ( GXRD) and changes of bacterial appearance on the surface of Cu un-implanted SS and Cu-implanted SS with antibacterial treatment SS were observed by bio-TEM (transmission electron microscopy) separately. The results showed that a suitable amount of Cu-rich phase was dispersed in the implanted layer of Cu-implanted SS that was treated by special antibacterial treatment. So the Cu-implanted martensitic stainless steel with antibacterial treatment reveals excellent antibacterial property against both E. coli and S. aureus.展开更多
The glutathione S-transferases gene family plays an important regulatory role in growth and development,and responses to environmental change.In this study,six complete GST genes(Mp GST1,Mp GST2,Mp GST3,MpGST4,Mp GST5...The glutathione S-transferases gene family plays an important regulatory role in growth and development,and responses to environmental change.In this study,six complete GST genes(Mp GST1,Mp GST2,Mp GST3,MpGST4,Mp GST5,and Mp GST6)were cloned from the gametophytes of brown alga Macrocystis pyrifera.Subsequent bioinformatics analysis showed that these six genes encoded proteins with 202,216,288,201,205,and 201 aa,respectively.Moreover,Mp GST3 differs from the other GST genes.Phylogenetic analysis suggested that MpGST3 belongs to the Ure2p type GST.Domain analysis suggested that the other GSTs from M.pyrifera belong to the soluble GST family and form an independent branch with the GSTs found in the other macroalgae,suggesting that a new GST type was formed during macroalgal evolution.GST genes were upregulated in M.pyrifera when 2.5 mg L^(-1)Cu ions were added to the medium.Six GST genes were integrated into the genome of Synechococcus elongatus PCC 7942,and their functions were verified by measuring light absorbance,photosynthetic pigment content,and photosynthetic parameters of the transformed strains under 0.3 mg L^(-1)Cu ion stress.The results showed much higher levels of various parameters in the transformed strains than in the wild strain.The transformed strains(with the MpGST genes)showed significantly enhanced resistance to Cu ion stress,while the wild strain almost died.The results of this study lay a theoretical foundation for further research on the Cu ion stress resistance function of GSTs in M.pyrifera.展开更多
This paper reports the results of spectral measurements and a theoretical analysis of the temporal and spatial evolution of laser-produced Cu plasma in vacuum in the range of 8–14 nm.The time dependence of the extrem...This paper reports the results of spectral measurements and a theoretical analysis of the temporal and spatial evolution of laser-produced Cu plasma in vacuum in the range of 8–14 nm.The time dependence of the extreme ultraviolet band spectrum at different positions near the target surface was obtained and found to be dominated by three broad-band features.The 3p and 3d excitations of Cu5+–Cu9+ions were calculated using the Hartree–Fock theory with configuration interactions.The characteristics of the spectral line distribution for the 3p–nd and 3d–nf transition arrays were analyzed.Based on the steady-state collisional radiation model and the normalized Boltzmann distribution,the complex spectral structure in the band of 13–14 nm is accurately explained through consistency comparisons and benchmarking between the experimental and theoretical simulation spectra,demonstrating that the structure mainly stems from the overlapping contribution of the 3d–4f and 3p–3d transition arrays for the Cu5+–Cu9+ions.These results may help in studying the radiation characteristics of isoelectronic series highly-charged ions involving the 3d excitation process.展开更多
Amino-functionalized magnetic nanoparticle （NH2-MNP） were prepared by a sol-gel approach. The adsorption behavior of Cu（II） ions on NH2-MNP was discussed systematically by batch experiments. The effects of initial...Amino-functionalized magnetic nanoparticle （NH2-MNP） were prepared by a sol-gel approach. The adsorption behavior of Cu（II） ions on NH2-MNP was discussed systematically by batch experiments. The effects of initial Cu（II） ions concentration, time, pH and temperature were investigated. In kinetic studies, the pseudo-second-order model was successfully employed, and the pseudo-first-order model substantiated that Cu（II） adsorption on NH2-MNP was a diffusion-based process. Langmuir model and Dubinin-Radushkevich model （R2〉0.99） were more corresponded with the adsorption isotherm data of Cu（II） ions than Freundlich model. The adsorption capacity was increased with the increment of temperature and pH. NH2-MNP remains excellent Cu（II） recoveries after reusing five adsorption and desorption cycles, making NH2-MNP a promising candidate for repetitively removing heavy metal ions from environmental water samples. According to the results obtained from adsorption activation energy and thermodynamic studies, it can be inferred that the main adsorption mechanism between absorbent and Cu（II） ions is ion exchange-surface complexation.展开更多
Utilization of visible light is of crucial importance for exploiting efficient semiconductor catalysts for solar water splitting. In this study, an advanced ion implantation method was utilized to dope Cu ions into Zn...Utilization of visible light is of crucial importance for exploiting efficient semiconductor catalysts for solar water splitting. In this study, an advanced ion implantation method was utilized to dope Cu ions into ZnO nanorod arrays for photoelectrochemical water splitting in visible light. X-ray diffraction （XRD） and X-ray photo-electron spectroscopy （XPS） results revealed that Cu^＋ together with a small amount of Cu^2＋ were highly dispersed within the ZnO nanorod arrays. The Cu ion doped ZnO nanorod arrays displayed extended optical absorption and enhanced photoelectrochemical performance under visible light illumination （A 〉 420 nm）. A considerable photocurrent density of 18 μA/cm^2 at 0.8 V （vs. a saturated calomel electrode） was achieved, which was about 11 times higher than that of undoped ZnO nanorod arrays. This study proposes that ion implantation could be an effective approach for developing novel visible-light-driven photocatalytic materials for water splitting.展开更多
To reduce the risk of implant-associated infections,we previously designed and developed a series of medical copper(Cu)-bearing titanium alloys that release Cu ions and hence play an antibacterial role.However,both ex...To reduce the risk of implant-associated infections,we previously designed and developed a series of medical copper(Cu)-bearing titanium alloys that release Cu ions and hence play an antibacterial role.However,both excessive and deficient Cu levels adversely affect human health;therefore,the aim of the present study was to comprehensively evaluate the short-and long-term biosafety of Cu-bearing titanium alloys(Ti6 Al4V-Cu and Ti-Cu)both in vitro and in vivo.Moreover,the predominant kinetic mechanism of Cu ions release and its effect on biosafety were also investigated.The results indicate that the biocompatibility of the Cu-bearing titanium alloys meets the requirements of ISO standards and the Cu ion release kinetics display a good correlation over the entire time period in the normal zero-order model with an almost constant release rate.The release rate maintained at a parts per billion level safe for humans;consequently,we can conclude that our Cu-bearing titanium alloys have satisfactory biocompatibility.展开更多
Charge characteristics and Cu2+ adsorption-desorption of soils with variable charge (latosol) and permanent charge (brown soil) and the relationship between them were studied by means of back-titration and adsorption ...Charge characteristics and Cu2+ adsorption-desorption of soils with variable charge (latosol) and permanent charge (brown soil) and the relationship between them were studied by means of back-titration and adsorption equilibrium respectively. The amount of variable negative charge was much less in variable-charge soil than in permanent-charge soil and increased with the pH in the system, but the opposite trend occurred in the points of zero charge (PZCs). The amount of Cu2+ ions sorbed by permanent-charge soil was more than that by variable-charge soil and increased with the increase of Cu2+ concentration within a certain range in the equilibrium solution. The amount of Cu2+ ions desorbed with KC1 from permanent-charge soil was more than that from variable-charge soil, but the amount of Cu2+ ions desorbed with de-ionized water from permanent-charge soil was extremely low whereas there was still a certain amount of desorption from variable-charge soil. The increase of PZC of soils with variable or permanent charge varied with the increment of Cu2+ ions added. When the same amount of Cu2+ ions was added, the increments of PZC and variable negative surface charge of permanent-charge soil were different from those of variable-charge soil.展开更多
To determine the environmental free metal ion activity was a recent hot issue. A method to measure low-level free cupric ion activity in soil solution extracted with 0.01 mol/L KNO3 was developed by using cupric ion-s...To determine the environmental free metal ion activity was a recent hot issue. A method to measure low-level free cupric ion activity in soil solution extracted with 0.01 mol/L KNO3 was developed by using cupric ion-selective electrode （ISE） and calibrating with Cu-buffer solution. Three copper buffers including iminodiacetic acid （IDA）, ethylenediamine （EN）, and glycine （Gly） were compared for calibrating the Cu-ISE curves in the range of free cupric ions （pCu^2＋） 7-13. The Cu-EN buffer showed the best electrode response and thus was applied as the calibration buffer. The pCu^2＋ of 39 contaminated agricultural soils around a copper mine was measured, ranging from 5.03 to 9.20. Most Cu in the soil solutions was found to be complexed with dissolved soil organic matters, averaging 98.1%. The proportion of free Cu^2＋ ions in the soil solutions decreased with the increasing of solution pH. Soluble Cu and free Cu^2＋ ions concentrations were analyzed by multiple linear regressions to evaluate the effects of soil properties on metal levels and speciation. The results showed that soil solution pH was the most significant factor influencing pCu^2＋ （with R^2 value of 0.76）, while not important for the soluble Cu concentration.展开更多
The decomposition and precipitation behaviors of a quenched Cu-15wt%Sn alloy as a function of aging temperature were investigated using transmission electron microscopy （TEM）. Focused ion beam （FIB） was employed t...The decomposition and precipitation behaviors of a quenched Cu-15wt%Sn alloy as a function of aging temperature were investigated using transmission electron microscopy （TEM）. Focused ion beam （FIB） was employed to assist TEM specimen preparation. At 300 ℃, the decomposition of the supersaturated phase occurred at grain boundaries, displaying a cellular morphology. The lamellae were found with and phases, rather than with the equilibrium e and phases. The and phases exhibit a welldefined orientation relationship （OR） as On the other hand, at 320 ℃, only incipient lamellar structures of several micron meters were observed, which were composed of the 6 and phases. At the same time, abundant intragranular precipitation of the e phase in the form of platelets was observed, and OR as （lil）J/ （001）, [110] J/[100] exists between e phase and the ct phase. These contrasting precipitation behaviors are discussed from the viewpoint of crystallographic coherency of these phases.展开更多
基金Project(M26012)supported by the Foundation of National Laboratory of Solid State Microstructures,China
文摘A series of Cu-substituted Ni_(0.5-x)Cu_xZn_(0.5)Fe_2O_4(x=0.12,0.16,0.20,0.24 and 0.28) spinel ferrites were prepared by conventional ceramic method to investigate the effects of Cu compositional variation on the structure and dielectric properties.XRD patterns demonstrate that all the samples are crystallized in single-phase cubic spinel structure and the lattice constant increases with increasing Cu content.White grains observed by SEM are Cu-rich phase.The dielectric constant versus frequency curve displays a normal dielectric behavior of spinel ferrites.While the frequency dependence of dielectric loss tangent is found to be abnormal,exhibiting a peak at certain frequency for all Cu-substituted Ni-Zn ferrites.A maximum of the resistivity is observed at x=0.2 due to the decrease of hopping electrons between Fe^(2+) and Fe^(3+) in per unit volume,which is in contrast with the Cu content dependence of dielectric constant and dielectric loss.
基金Supported by the National Natural Science Foundation of China (No. 10975020)Key Laboratory of BeamTechnology and Material Modification of Ministry of Education, Beijing Normal University
文摘Highly oxidation. SEM analysis ordered anatase titania nanotube method was used to characterize arrays （TINT） were fabricated by anodic the morphology of the prepared samples. TiNT samples doped with Cu ions were prepared by home-made Metal Vapor Vacuum Arc ions sources （MEVVA, BNU, China） implanter. Photo-electric response and methyl orange decomposition ability of implanted samples under UV and visible light were tested, and the results indicated that the performance of Cu/TiNT enhanced significantly under visible light; it was noteworthy that the photocurrent density of A-Cu/TiNT was 0.102 mA/cm^2, which was 115 times that of pure TINT, and degradation ability of TiNT also strongly enhanced under visible light. In a word, the absorption spectrum of implanted anatase titania shifted to a longer wavelength region. Theoretic study on Cu-doped anatase based on density functional theory was carried out in this paper to validate the experiment results. The calculation results are depicted as follows： Intermittent energy band appeared around the Fermi energy after doping with Cu metal, the width of which was 0.35 eV and the location of valence and conduction bands shifted to the lower energy level by 0.22 eV; more excitation and jump routes were opened for the electrons. The narrowed band gaps allowed the photons with lower energy （at longer wavelength, such as visible light） to be absorbed, which accorded well with the experimental results.
基金Supported by the National Natural Science Foundation of China under Grant No 11405114the Natural Science Foundation of Shanxi Province under Grant No 2015021065
文摘Cu ion implantation and subsequent rapid annealing at 500℃ in N2 result in low surface resistivity of 1.611 ohm/sq with high mobility of 290 cm2 V-1S-1 for microcrystalline diamond （MCD） films. Its electrical field emission behavior can be turned on at Eo = 2.6 V/μm, attaining a current density of 19.5μA/cm2 at an applied field of 3.5 V/#m. Field emission scanning electron microscopy combined with Raman and x-ray photoelectron mi- croscopy reveal that the formation of Cu nanoparticles in MCD films can catalytically convert the less conducting disorder/a-C phases into graphitic phases and can provoke the formation of nanographite in the films, forming conduction channels for electron transportation.
基金supported by The National Natural Science Foundation of China(Grant No.50101009)
文摘Copper ions were implanted into a AISI420 martensitic stainless steel (SS) by metal vapor vacuum arc (MEVVA) with a dose range 0.2 xlO17 -S.OxlO17 cm"2 at the energy of lOOkeV. The Cu-implanted stainless steel was treated by a special antibacterial treatment subsequently. The phase compositions in the implanted layer were studied by glancing X-ray diffraction ( GXRD) and changes of bacterial appearance on the surface of Cu un-implanted SS and Cu-implanted SS with antibacterial treatment SS were observed by bio-TEM (transmission electron microscopy) separately. The results showed that a suitable amount of Cu-rich phase was dispersed in the implanted layer of Cu-implanted SS that was treated by special antibacterial treatment. So the Cu-implanted martensitic stainless steel with antibacterial treatment reveals excellent antibacterial property against both E. coli and S. aureus.
基金supported by the National Key R&D Program of China(No.2018YFD0900305)the National Natural Science Foundation of China(No.31770393)+5 种基金the Major Scientific and Technological Innovation Project of Shandong Provincial Key Research and Development Program(No.2019JZZY020706)the Central Public-Interest Scientific Institute Basal Research Fund,CAFS(Nos.2020TD 19 and 2020TD27)the China Agriculture Research System(CARS-50)the Taishan Scholars Funding of Shandong Provincethe Taishan Scholars Funding and Talent Projects of Distinguished Scientific Scholars in AgricultureYoung Taishan Scholars Program to DONG Xu。
文摘The glutathione S-transferases gene family plays an important regulatory role in growth and development,and responses to environmental change.In this study,six complete GST genes(Mp GST1,Mp GST2,Mp GST3,MpGST4,Mp GST5,and Mp GST6)were cloned from the gametophytes of brown alga Macrocystis pyrifera.Subsequent bioinformatics analysis showed that these six genes encoded proteins with 202,216,288,201,205,and 201 aa,respectively.Moreover,Mp GST3 differs from the other GST genes.Phylogenetic analysis suggested that MpGST3 belongs to the Ure2p type GST.Domain analysis suggested that the other GSTs from M.pyrifera belong to the soluble GST family and form an independent branch with the GSTs found in the other macroalgae,suggesting that a new GST type was formed during macroalgal evolution.GST genes were upregulated in M.pyrifera when 2.5 mg L^(-1)Cu ions were added to the medium.Six GST genes were integrated into the genome of Synechococcus elongatus PCC 7942,and their functions were verified by measuring light absorbance,photosynthetic pigment content,and photosynthetic parameters of the transformed strains under 0.3 mg L^(-1)Cu ion stress.The results showed much higher levels of various parameters in the transformed strains than in the wild strain.The transformed strains(with the MpGST genes)showed significantly enhanced resistance to Cu ion stress,while the wild strain almost died.The results of this study lay a theoretical foundation for further research on the Cu ion stress resistance function of GSTs in M.pyrifera.
基金supported by National Natural Science Foundation of China(Nos.12064040,11874051,11904293,11864036)the Science and Technology Project of Gansu Province(Nos.21JR7RA122,20JR5RA530)the Funds for Innovative Fundamental Research Group Project of Gansu Province(No.20JR5RA541)。
文摘This paper reports the results of spectral measurements and a theoretical analysis of the temporal and spatial evolution of laser-produced Cu plasma in vacuum in the range of 8–14 nm.The time dependence of the extreme ultraviolet band spectrum at different positions near the target surface was obtained and found to be dominated by three broad-band features.The 3p and 3d excitations of Cu5+–Cu9+ions were calculated using the Hartree–Fock theory with configuration interactions.The characteristics of the spectral line distribution for the 3p–nd and 3d–nf transition arrays were analyzed.Based on the steady-state collisional radiation model and the normalized Boltzmann distribution,the complex spectral structure in the band of 13–14 nm is accurately explained through consistency comparisons and benchmarking between the experimental and theoretical simulation spectra,demonstrating that the structure mainly stems from the overlapping contribution of the 3d–4f and 3p–3d transition arrays for the Cu5+–Cu9+ions.These results may help in studying the radiation characteristics of isoelectronic series highly-charged ions involving the 3d excitation process.
基金Project(CXZZ11-0812)supported by Graduate Students Innovative Projects of Jiangsu Province,ChinaProject(J20122288)supported by Guizhou Provincial Natural Science Foundation of China+1 种基金Project(Y4110235)supported by Zhejiang Provincial Natural Science Foundation of ChinaProject(JKY2011008)supported by Fundamental Research Funds for the Central Universities,China
文摘Amino-functionalized magnetic nanoparticle （NH2-MNP） were prepared by a sol-gel approach. The adsorption behavior of Cu（II） ions on NH2-MNP was discussed systematically by batch experiments. The effects of initial Cu（II） ions concentration, time, pH and temperature were investigated. In kinetic studies, the pseudo-second-order model was successfully employed, and the pseudo-first-order model substantiated that Cu（II） adsorption on NH2-MNP was a diffusion-based process. Langmuir model and Dubinin-Radushkevich model （R2〉0.99） were more corresponded with the adsorption isotherm data of Cu（II） ions than Freundlich model. The adsorption capacity was increased with the increment of temperature and pH. NH2-MNP remains excellent Cu（II） recoveries after reusing five adsorption and desorption cycles, making NH2-MNP a promising candidate for repetitively removing heavy metal ions from environmental water samples. According to the results obtained from adsorption activation energy and thermodynamic studies, it can be inferred that the main adsorption mechanism between absorbent and Cu（II） ions is ion exchange-surface complexation.
基金The authors gratefully acknowledge the financial support of the National Natural Science Foundation of China （Nos. 51102194, 51323011, and 51121092）, the Doctoral Program of the Ministry of Education （No. 20110201120040） and the Nano Research Program of Suzhou City （ZXG2013003）. S. Shen is supported by the Foundation for the Author of National Excellent Doctoral Dissertation of China （No. 201335） and the Fundamental Research Funds for the Central Universities.
文摘Utilization of visible light is of crucial importance for exploiting efficient semiconductor catalysts for solar water splitting. In this study, an advanced ion implantation method was utilized to dope Cu ions into ZnO nanorod arrays for photoelectrochemical water splitting in visible light. X-ray diffraction （XRD） and X-ray photo-electron spectroscopy （XPS） results revealed that Cu^＋ together with a small amount of Cu^2＋ were highly dispersed within the ZnO nanorod arrays. The Cu ion doped ZnO nanorod arrays displayed extended optical absorption and enhanced photoelectrochemical performance under visible light illumination （A 〉 420 nm）. A considerable photocurrent density of 18 μA/cm^2 at 0.8 V （vs. a saturated calomel electrode） was achieved, which was about 11 times higher than that of undoped ZnO nanorod arrays. This study proposes that ion implantation could be an effective approach for developing novel visible-light-driven photocatalytic materials for water splitting.
基金funded by the National Key Research and Development Program of China(2018YFC1106600,2016YFC1100600)LiaoNing Revitalization Talents Program(XLYC1807069)+1 种基金National Natural Science Foundation(Nos.51631009,31870954,81873918)Startup Fundation for Docotors of Liaoning Province(NO.2019BS-293)。
文摘To reduce the risk of implant-associated infections,we previously designed and developed a series of medical copper(Cu)-bearing titanium alloys that release Cu ions and hence play an antibacterial role.However,both excessive and deficient Cu levels adversely affect human health;therefore,the aim of the present study was to comprehensively evaluate the short-and long-term biosafety of Cu-bearing titanium alloys(Ti6 Al4V-Cu and Ti-Cu)both in vitro and in vivo.Moreover,the predominant kinetic mechanism of Cu ions release and its effect on biosafety were also investigated.The results indicate that the biocompatibility of the Cu-bearing titanium alloys meets the requirements of ISO standards and the Cu ion release kinetics display a good correlation over the entire time period in the normal zero-order model with an almost constant release rate.The release rate maintained at a parts per billion level safe for humans;consequently,we can conclude that our Cu-bearing titanium alloys have satisfactory biocompatibility.
基金Project (Nos.49831005 and 49871043) supported by the National Natural Science Foundation of China.
文摘Charge characteristics and Cu2+ adsorption-desorption of soils with variable charge (latosol) and permanent charge (brown soil) and the relationship between them were studied by means of back-titration and adsorption equilibrium respectively. The amount of variable negative charge was much less in variable-charge soil than in permanent-charge soil and increased with the pH in the system, but the opposite trend occurred in the points of zero charge (PZCs). The amount of Cu2+ ions sorbed by permanent-charge soil was more than that by variable-charge soil and increased with the increase of Cu2+ concentration within a certain range in the equilibrium solution. The amount of Cu2+ ions desorbed with KC1 from permanent-charge soil was more than that from variable-charge soil, but the amount of Cu2+ ions desorbed with de-ionized water from permanent-charge soil was extremely low whereas there was still a certain amount of desorption from variable-charge soil. The increase of PZC of soils with variable or permanent charge varied with the increment of Cu2+ ions added. When the same amount of Cu2+ ions was added, the increments of PZC and variable negative surface charge of permanent-charge soil were different from those of variable-charge soil.
基金Project(2004CB619205)supported by the National Basic Research Program of ChinaProject(50674102)supported by the National Natural Science Foundation of ChinaProject(2007AA060902)supported by High-tech Research and Development Program of China
基金The National Key Basic Research Program (973) of China (No. 2002CB410808) and CAS Research Program on Soil Biosystems andAgro-Product Safety (No. CXTD-Z2005-4-1)
文摘To determine the environmental free metal ion activity was a recent hot issue. A method to measure low-level free cupric ion activity in soil solution extracted with 0.01 mol/L KNO3 was developed by using cupric ion-selective electrode （ISE） and calibrating with Cu-buffer solution. Three copper buffers including iminodiacetic acid （IDA）, ethylenediamine （EN）, and glycine （Gly） were compared for calibrating the Cu-ISE curves in the range of free cupric ions （pCu^2＋） 7-13. The Cu-EN buffer showed the best electrode response and thus was applied as the calibration buffer. The pCu^2＋ of 39 contaminated agricultural soils around a copper mine was measured, ranging from 5.03 to 9.20. Most Cu in the soil solutions was found to be complexed with dissolved soil organic matters, averaging 98.1%. The proportion of free Cu^2＋ ions in the soil solutions decreased with the increasing of solution pH. Soluble Cu and free Cu^2＋ ions concentrations were analyzed by multiple linear regressions to evaluate the effects of soil properties on metal levels and speciation. The results showed that soil solution pH was the most significant factor influencing pCu^2＋ （with R^2 value of 0.76）, while not important for the soluble Cu concentration.
基金supported by the China Scholarship Council(No.2010602038)the Ministry of Science and Technology of China(No.2010DFA51650)
文摘The decomposition and precipitation behaviors of a quenched Cu-15wt%Sn alloy as a function of aging temperature were investigated using transmission electron microscopy （TEM）. Focused ion beam （FIB） was employed to assist TEM specimen preparation. At 300 ℃, the decomposition of the supersaturated phase occurred at grain boundaries, displaying a cellular morphology. The lamellae were found with and phases, rather than with the equilibrium e and phases. The and phases exhibit a welldefined orientation relationship （OR） as On the other hand, at 320 ℃, only incipient lamellar structures of several micron meters were observed, which were composed of the 6 and phases. At the same time, abundant intragranular precipitation of the e phase in the form of platelets was observed, and OR as （lil）J/ （001）, [110] J/[100] exists between e phase and the ct phase. These contrasting precipitation behaviors are discussed from the viewpoint of crystallographic coherency of these phases.
