Effects of samarium (Sm) content (0, 2.0, 3.5, 5.0, 6.5 wt%) on microstructure and mechanical proper-ties of Mg-0.5Zn-0.5 Zr alloy under as-cast and as-extruded states were thoroughly investigated. Results indicate th...Effects of samarium (Sm) content (0, 2.0, 3.5, 5.0, 6.5 wt%) on microstructure and mechanical proper-ties of Mg-0.5Zn-0.5 Zr alloy under as-cast and as-extruded states were thoroughly investigated. Results indicate that grains of the as-cast alloys are gradually refined as Sm content increases. The dominant intermetallic ph^se changes from Mg3Sm to Mg4iSm5 till Sm content exceeds 5.0 wt%. The dynami-cally precipitated intermetallic phase during hot-extrusion in dll Sm-containing alloys is Mg3Sm. The intermetallic particles induced by Sm addition could act as heterogeneous nucleation sites for dynamic recrystallization during hot extrusion. They promoted dynamic recrystallization via the particle stim-ulated nucleation mechanism, and resulted in weakening the basal texture in the as-extruded alloys. Sm addition can significantly enhance the strength of the as-extruded Mg-0.5Zn-0.5Zr alloy at room temperature, with the optimal dosage of 3.5 wt%. The optimal yield strength (YS) and ultimate tensile strength (UTS) are 368 MPa and 383 MPa, which were enhanced by approximately 23.1% and 20.8% com-pared with the Sm-free alloy, respectively. Based on microstructural analysis, the dominant strengthening mechanisms are revealed to be grain boundary strengthening and dispersion strengthening.展开更多
The microstructure and mechanical properties of AZ61 magnesium alloy with Ca, Sm addition were investigated. The results showed that the addition of 0.5 wt.% Ca reduced the quantity of Mg17Al12 phase, and formed a new...The microstructure and mechanical properties of AZ61 magnesium alloy with Ca, Sm addition were investigated. The results showed that the addition of 0.5 wt.% Ca reduced the quantity of Mg17Al12 phase, and formed a new Al4 Ca phase which is reticular in AZ61 alloy. With the addition of Ca and Sm, the microstructure was further refined and new Al-Sm rich phases were formed in AZ61 alloy with 0.6 wt.%-1.5 wt.% Sm addition, the TEM analysis confirmed that they were Al2 Sm and Al4 Sm. Tensile tests showed that 1.0 wt.% Sm addition contributed to the formation of the Al2 Sm and Al4 Sm and the improvement in the ambient strength, i.e., an ultimate tensile strength of 327 MPa and an elongation of 10.1%. However, excessive Sm addition led to the coarsening of Al2 Sm and Al4 Sm phases, thus resulted in the decline of strength and plasticity.展开更多
Samarium–cobalt rare-earth（Sm–Co-RE） permanent magnetic materials with large magnetic energy product, high coercive force, high Curie temperature, good thermal stability, and corrosion resistance, have wide potent...Samarium–cobalt rare-earth（Sm–Co-RE） permanent magnetic materials with large magnetic energy product, high coercive force, high Curie temperature, good thermal stability, and corrosion resistance, have wide potential applications in aerospace, microwave communications, instrumentation, electrical engineering, magnetic machinery, etc. In this paper, the development of Sm–CoRE permanent magnetic materials in the following aspects in recent years was summarized： Sm–Co-RE permanent magnets with high application temperatures, positive temperature coefficients of coercive force, zero temperature coefficients of residual magnetization, high resistance rate,high mechanical property, and nanocrystallization.展开更多
A Box-Behnken design （BBD） of response surface methodology （RSM） was used to optimize the preparation of the Zn-Sm antibacterial white carbon black by the sol-gel method. The statistical analysis of the results sh...A Box-Behnken design （BBD） of response surface methodology （RSM） was used to optimize the preparation of the Zn-Sm antibacterial white carbon black by the sol-gel method. The statistical analysis of the results showed that the particle size of the Zn-Sm antibacterial white carbon black was significantly affected by the reaction time, reaction temperature and the stirring speed. According to analysis of variance （ANOVA）, the values of the determination coefficient （R2=0.9821） and the ＂Pred R-Squared＂ of 0.8227 were in reasonable agreement with the ＂Adj R-Squared＂ of 0.9591. It was indicated that this model could be used to navigate the design space. The optimized reaction time, temperature and the stirring speed were 0.88 h, 87.83 ℃, and 473.45 r/rain, respectively. In addition, the bacteriostasis rate of the product was about 97.92%.展开更多
The efficiency of activated biochar fibres obtained from Opuntia Ficus lndica regarding me sorpuon oi trlvalent samarium （Sm（Ⅲ）） from aqueous solutions was investigated by batch experiments. The effect of various...The efficiency of activated biochar fibres obtained from Opuntia Ficus lndica regarding me sorpuon oi trlvalent samarium （Sm（Ⅲ）） from aqueous solutions was investigated by batch experiments. The effect of various physicochemical parameters （e.g. pH, initial metal concentration, ionic strength, temperature and contact time） on the Sm（III） adsorption was studied and the surface species were characterized by FTIR spectroscopy prior to and after the lanthanide sorption. The experimental results showed that the acti- vated biochar fibres possessed extraordinary sorption capacity for Sm（Ⅲ） in acidic solutions （qmax=90 g/kg, pH 3.0） and near neutral solutions （qmax=350 g/kg, pH 6.5）, This was attributed to the formation of samarium complexes with the surface carboxylic moieties, available in high density on the lamellar structures of the bio-sorbent.展开更多
The solvent extraction of Pr(Ⅲ) and Sm(Ⅲ) with trialkyl phosphine oxide(Cyanex 923) in chloroform,carbon tetrachloride,n-octane,cyclohexane,1,2-dichloroethane,benzene,toluene,xylene and nitrobenzene from acidic nitr...The solvent extraction of Pr(Ⅲ) and Sm(Ⅲ) with trialkyl phosphine oxide(Cyanex 923) in chloroform,carbon tetrachloride,n-octane,cyclohexane,1,2-dichloroethane,benzene,toluene,xylene and nitrobenzene from acidic nitrate medium was investigated.On the basis of slope analysis data,the composition of the extracted species was determined as(M(NO3)3?2CY923),CY923 refers to Cyanex 923.The values of the equilibrium constants and the separation factors were calculated.The effect of the diluents on the metal extracti...展开更多
The effects of samarium（Sm） on microstructure and corrosion resistance of AZ92 magnesium alloy were characterized and analyzed by scanning electronic microscopy, X-ray diffraction, mass loss test, electrochemical im...The effects of samarium（Sm） on microstructure and corrosion resistance of AZ92 magnesium alloy were characterized and analyzed by scanning electronic microscopy, X-ray diffraction, mass loss test, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy and potentio-dynamic polarization test. The results showed that the added Sm could promote continuous precipitation of β-Mg17Al12 phase in grains, and meanwhile restrain discontinuous precipitation of the same phase along the grain boundaries. Thus, the precipitations distributed more uniformly in the aged AZ92 magnesium alloys. When the content of Sm was 0.5 wt.%, the corrosion resistance of aged AZ92 alloy tended to be the best, which was due to the β-phase distributes more homogeneous reducing the galvanic corrosion. The corrosion product film had more integrality and compactness than AZ92 alloys without Sm. However, it resulted in worse corrosion resistance of AZ92 alloy because of the formation of mass cathodic Al2 Sm phase coming from excess Sm in AZ92 alloy.展开更多
The effects of samarium(Sm) on carbon-methanation and catalytic activity of the Ba-Ru-K/AC (active carbon) catalyst for ammonia synthesis were investigated. The addition of samarium improved significantly the activity...The effects of samarium(Sm) on carbon-methanation and catalytic activity of the Ba-Ru-K/AC (active carbon) catalyst for ammonia synthesis were investigated. The addition of samarium improved significantly the activity and stability of the catalyst. The results of temperature-programmed desorption (H2-TPD) and in-situ-TPSR FTIR indicated that samarium impeded the adsorption of hydrogen on the catalyst surface, thus leading to the high catalytic activity and resistance to carbon-methanation. XRD patterns reve...展开更多
Trivalent samarium ion (Sm^(3+)) activated calcium molybdate (CaMoO_4) phosphor was prepared by solid-state reaction in air. The XRD pattern of the powder CaMoO_4∶Sm shows that the CaMoO_4∶Sm single phase is develop...Trivalent samarium ion (Sm^(3+)) activated calcium molybdate (CaMoO_4) phosphor was prepared by solid-state reaction in air. The XRD pattern of the powder CaMoO_4∶Sm shows that the CaMoO_4∶Sm single phase is developed fully through our preparation procedure. The excitation spectrum of CaMoO_4∶Sm is composed of a broad absorption of host and some sharp lines of the f-f transition absorption of Sm^(3+). Illustrated in photoluminescence spectrum, CaMoO_4 doped with Sm^(3+) displays orange red emission that is ascribed to the inner 4f^5 electron transitions ~6H_(7/2)(orange)and ~6H_(9/2)(red)of Sm^(3+). Different from the sites of Sm^(3+) in CdWO_4, the Sm^(3+) ions substitute for the Ca^(2+) and form only one type emission center in the CaMoO_4 crystal lattice.展开更多
An inorganic nanomaterials combination of Sm, Ag, and TiO2 was synthesized using supercritical fluid drying （SCFD） combined with solgel techniques. The structure, photocatalysis and bacteriostatic activity of the ma...An inorganic nanomaterials combination of Sm, Ag, and TiO2 was synthesized using supercritical fluid drying （SCFD） combined with solgel techniques. The structure, photocatalysis and bacteriostatic activity of the materials were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, X-ray photoelectron spectroscopy （XRPS）, photocatalytic performance, and antibacterial activity experiments. The XRD results showed that the average particle diameter of Sm/Ag/TiO2 was 14.62 nm and Ag and Sm ions were dispersed on the surface of TiO2 in a highly dispersed, amorphous form. The TEM image showed that the size of the particle was 12 nm using the scherer formula. The XPS result showed that the element Sm was doped and Ag was loaded inorganic nanomaterials successfully. Sm/Ag/TiO2 exhibited optimal photocatalytic properties at 600 oC, the photocatalytic optimal proportion of Sm/Ag/TiO2 was 2：2：100. When the molar ratio was 2：2：100, the bacteriostatic circle diameter was 16 mm for Staphylococcus aureus, the minimum bacteriostatic concentration was 200μg/mL for white beads coccus, and the minimum bactericidal concentration was 2×10^4μg/mL for white beads coccus. The SEM results showed that the antibacterial material attached to the candida albicans cell surface, cells appeared fold deformation. Therefore the inorganic nanomaterials Sm/Ag/TiO2 had high temperature resistance, good photocatalytic and antibacterial characteristics in visible light.展开更多
The mechanical properties of Al-Cu-Mn casting alloy mainly depend on the morphology, distribution, size, and number ofθ′（Al2Cu） precipitates. In this study, we have analyzed the effect of rare earth samarium （Sm...The mechanical properties of Al-Cu-Mn casting alloy mainly depend on the morphology, distribution, size, and number ofθ′（Al2Cu） precipitates. In this study, we have analyzed the effect of rare earth samarium （Sm） addition on the kinetics of precipitation in the Al-Cu-Mn casting alloy by using differential scanning calorimetry （DSC） and high-resolution transmission electron microscopy. Thermal ef-fect peaks that are attributed to the formation and the dissolution of Guinier-Preston （GP） zone andθ′phase were identified from the DSC curves. The activation energy ofθ′formation was calculated by using both the Kissinger method and the analytical model, and the corre-sponding results were compared. Results suggest that the activation energy ofθ′formation in Al-Cu-Mn alloy is dramatically higher than that in Al-Cu-Mn-Sm alloy. Accordingly, it is concluded that the addition of rare earth Sm decreases the activation energy ofθ′formation and promotes the formation ofθ′precipitates.展开更多
Gaseous penetration technique was adopted to improve the electrical conductivity of BaTiO3 powders and the effects of penetration temperature on the structure and electrical conductivity of Sm-modified BaTiO3 powders ...Gaseous penetration technique was adopted to improve the electrical conductivity of BaTiO3 powders and the effects of penetration temperature on the structure and electrical conductivity of Sm-modified BaTiO3 powders were studied.It was observed that the penetration of Sm made the resistivity of BaTiO3 powders decrease with the increase in the penetration temperature and decreased to the lowest point of 4.20×102 ？·m when the penetration temperature was 950 oC.The relationship curve of the temperature and resistivity of the samples was also established preliminarily to get the mathematical expression by the fitting method.Through X-ray diffraction （XRD） analysis,the new phases of Sm2O3 and Ba4Ti2O27 were detected.It was indicated that intricate reactions related to Sm took place during the penetration process and led to the Ti-rich state of the system.The Fourier transform infrared （FTIR） spectrum illustrated that the bonds of Ti–O octahedron was strengthened by substitution of Sm3＋ at Ti4＋ sites,which led to the growth of Ti：Ba ratio.The analysis results of scanning electron microscopy （SEM） indicated that the particle size of Sm-modified BaTiO3 powders progressed with the penetration temperature increasing.展开更多
The electrochemical behaviour of samarium was investigated in LiF-BeF2 system on an inert （Mo） electrode by cyclic voltammetry and chronopotentiometry at 804, 833, 847 and 872 K. Redox process Sm3＋＋e–→Sm2＋ was ...The electrochemical behaviour of samarium was investigated in LiF-BeF2 system on an inert （Mo） electrode by cyclic voltammetry and chronopotentiometry at 804, 833, 847 and 872 K. Redox process Sm3＋＋e–→Sm2＋ was recognized and analysed. Cyclic voltammetry data suggested that at potential sweep rates lower than 0.25 V/s, the reduction was limited by the diffusion of Sm3＋ ions. It was not possible to observe reduction process of Sm2＋＋2e–→Sm0 due to insufficient electrochemical stability of LiF-BeF2. Diffusion coefficients of Sm3＋ ions in LiF-BeF2 were calculated from voltammetric and chronopotentiometric data in the temperature range 804–872 K. Diffusion coefficient values obeyed Arrhenius law. Activation energy was calculated to be 102.5 kJ/mol.展开更多
Nanometer crystal samarium borate with a particle size of 20～40?nm was prepared using replacing solvent drying technique. The wear resistance and load carrying capacity of 500SN base oil could be improved and the fri...Nanometer crystal samarium borate with a particle size of 20～40?nm was prepared using replacing solvent drying technique. The wear resistance and load carrying capacity of 500SN base oil could be improved and the friction coefficient could be decreased by the addition of nanometer samarium borate. But the dosage of samarium borate nanoparticles had to be controlled at a relatively low level, a higher concentration of nanoparticles was not of beneficial to the tribological performance of the oil. The optimal dosage of nanometer samarium borate is 1.0%. Tribochemical reactions took place in the tribological process, which resulted in the formation of deposition products including diboron trioxide and disamarium trioxide. Fe 2B and FeB were also found on the wear scar. The improvement of tribological properties of the oil comes from the formation of deposition layer and permeating layer. [展开更多
A complex [Sm（2-IBA）2（2,2’-bipy）（NO3）]2 （2-HIBA=2-idobenzoic acid; 2,2’-bipy=2,2’-bipyridine） was synthesized by solvent method and characterized by X-ray single-crystal diffraction. The complex crystallize...A complex [Sm（2-IBA）2（2,2’-bipy）（NO3）]2 （2-HIBA=2-idobenzoic acid; 2,2’-bipy=2,2’-bipyridine） was synthesized by solvent method and characterized by X-ray single-crystal diffraction. The complex crystallized in triclinic crystal system, Pī space group, with a= 0.97873（3） nm, b=1.28124（3） nm, c=1.29174（3） nm, α=108.3740（10）o, β=111.7340（10）o, γ=101.7870（10）o. The complex was the centrosymmetric binuclear molecule, in which two Sm3＋ ions were connected by four 2-IBA ligands. Two of the 2-IBA ligands were in a bidentate bridging mode and the other two were in a tridentate bridging mode. Sm3＋ ion was also coordinated to one chelating NO3– group and one 2,2’-bipy molecule. The 2D supramolecular network formed through weak I…I interactions and π…π stacking interactions. The fluorescent emission peaks at 562, 595, and 642 nm corresponded to the 4G5/2→6F5/2, 4G5/2→6F7/2, and 4G5/2→6F9/2 transitions of Sm3＋ ion, respectively.展开更多
A series of samarium(Sm)doped hydroxyapatites containing strontium(Sr)with controllable and adjustable luminescence were designed and prepared via chemical hydrolysis co-precipitation method.The effects of doping conc...A series of samarium(Sm)doped hydroxyapatites containing strontium(Sr)with controllable and adjustable luminescence were designed and prepared via chemical hydrolysis co-precipitation method.The effects of doping concentration of Sm on the structure,composition,photoluminescence(PL),energy transfer,substitute site,fluoresce lifetime and luminescence color of samples were investigated.It is shown that the introduction of Sr ions induces the structure and composition change for Sm doped samples.The typical transitions of Sm^(3+) at 564,601,648 and 707 nm due to^(4)G_(5/2)→^(6)H_(J/2)(J=5,7,9 and 11)transition under the excitation of 404 nm were detected.The PL intensity is affected by the Sr/Ca ratio and Sm concentration,and the optimal concentration of Sm is 0.8 mol%when Sr/Ca ratio equals 7/3.The non-radiative transitions and energy transfer of Sm ions are the main reason for the quenching,and the interactions among ions are ascribed to dipole-dipole type by theoretical calculation.Besides,the ratio of PL intensity between 601 and 648 nm(r_(O/R)=I_(601nm)/I_(648nm))indicates the symmetry and substitution process of Sm ions to Ca/Sr ions.The fluorescence lifetime(τ)decreases with the concentration of Sm increasing,which is the result of the decrease of distance and the enhanced interaction between Sm ions.The CIE chromaticity coordinates and luminescence color of samples are in the orange-red region and have close relation with the concentration of Sm.Furthermore,the cytotoxicity evaluation and confocal laser scanning microscopy(CLSM)observation of samples via cells indicate the good biocompatibility and safe use of this kind of bio-based luminescent materials for their potential efficient fluorescence labeling and detection.展开更多
The polymerization of acrylonitrile initiated by organolanthanide complexes alone is studied for the first time. The effect of polymerization conditions on catalytic activity of the title complex and molecular weight ...The polymerization of acrylonitrile initiated by organolanthanide complexes alone is studied for the first time. The effect of polymerization conditions on catalytic activity of the title complex and molecular weight of the polymers produced have been studied.展开更多
A novel 1064 tun laser stealth absorbent of SmzO2S was prepared by flux method. The effects of different calcining temperatures and fluxes on the reflective property of Sm2O2S were investigated. The phase composition,...A novel 1064 tun laser stealth absorbent of SmzO2S was prepared by flux method. The effects of different calcining temperatures and fluxes on the reflective property of Sm2O2S were investigated. The phase composition, morphology, and reflectivity of the powders were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and ultraviolet-visible spectrophotometer （UVPC）. The results showed that pure phase of Sm202S could be obtained with Na2CO3 as flux above 950~C, and the reflectivity decreased with the calcination temperature increasing. Compared with other samarium compounds, the reflectivity at 1064 nm of Sm2O2S was the lowest. Different fluxes had great impact on the phase composition, particle morphology, and reflectivity of the products. In short, Sm2O2S was suitable as a kind of absorbent against 1064 nm laser.展开更多
The influence of Sm （Samarium） content on microstructure and mechanical properties of recycled die-cast YLl12 aluminum alloys was investigated. The results show that many small Sm-rich particles form in the recycled...The influence of Sm （Samarium） content on microstructure and mechanical properties of recycled die-cast YLl12 aluminum alloys was investigated. The results show that many small Sm-rich particles form in the recycled die-cast YLl12 alloys with Sm addition. At the same time, the secondary dendrite arm spacing in the YLl12 alloys modified with Sm is smaller than that of the unmodified alloy. The eutectic Si of recycled die- cast YL112-xSm alloys transforms from coarse acicular morphology to fine fibres. Mechanical properties of the investigated recycled die-cast YLl12 aluminum alloys are enhanced with Sm addition, and a maximal ultimate tensile strength value （276 MPa） and elongation （3.76%） are achieved at a Sm content of 0.6wt.%. Due to the modification of eutectic Si by Sm, numerous tearing ridges and tiny dimples on the fractures of tensile samples are observed.展开更多
基金supported financially by the National Natural Science Foundation of China (Nos. 51701200 and 21601017)the Project for Science & Technology Development of Jilin Province (Nos. 2016YHZ0006, 20170414001GH, 20180520004JH and 20180520160JH)
文摘Effects of samarium (Sm) content (0, 2.0, 3.5, 5.0, 6.5 wt%) on microstructure and mechanical proper-ties of Mg-0.5Zn-0.5 Zr alloy under as-cast and as-extruded states were thoroughly investigated. Results indicate that grains of the as-cast alloys are gradually refined as Sm content increases. The dominant intermetallic ph^se changes from Mg3Sm to Mg4iSm5 till Sm content exceeds 5.0 wt%. The dynami-cally precipitated intermetallic phase during hot-extrusion in dll Sm-containing alloys is Mg3Sm. The intermetallic particles induced by Sm addition could act as heterogeneous nucleation sites for dynamic recrystallization during hot extrusion. They promoted dynamic recrystallization via the particle stim-ulated nucleation mechanism, and resulted in weakening the basal texture in the as-extruded alloys. Sm addition can significantly enhance the strength of the as-extruded Mg-0.5Zn-0.5Zr alloy at room temperature, with the optimal dosage of 3.5 wt%. The optimal yield strength (YS) and ultimate tensile strength (UTS) are 368 MPa and 383 MPa, which were enhanced by approximately 23.1% and 20.8% com-pared with the Sm-free alloy, respectively. Based on microstructural analysis, the dominant strengthening mechanisms are revealed to be grain boundary strengthening and dispersion strengthening.
基金supported by International Science and Technological Cooperating Project of the Ministry of Science and Technology of the PRC(2008DFR50040-08)
文摘The microstructure and mechanical properties of AZ61 magnesium alloy with Ca, Sm addition were investigated. The results showed that the addition of 0.5 wt.% Ca reduced the quantity of Mg17Al12 phase, and formed a new Al4 Ca phase which is reticular in AZ61 alloy. With the addition of Ca and Sm, the microstructure was further refined and new Al-Sm rich phases were formed in AZ61 alloy with 0.6 wt.%-1.5 wt.% Sm addition, the TEM analysis confirmed that they were Al2 Sm and Al4 Sm. Tensile tests showed that 1.0 wt.% Sm addition contributed to the formation of the Al2 Sm and Al4 Sm and the improvement in the ambient strength, i.e., an ultimate tensile strength of 327 MPa and an elongation of 10.1%. However, excessive Sm addition led to the coarsening of Al2 Sm and Al4 Sm phases, thus resulted in the decline of strength and plasticity.
基金financially supported by the Research Fund for the Doctoral Program of Higher Education of China (No.20100560)the National Natural Science Foundation of China (Nos. 51104188 and 51274107)
文摘Samarium–cobalt rare-earth（Sm–Co-RE） permanent magnetic materials with large magnetic energy product, high coercive force, high Curie temperature, good thermal stability, and corrosion resistance, have wide potential applications in aerospace, microwave communications, instrumentation, electrical engineering, magnetic machinery, etc. In this paper, the development of Sm–CoRE permanent magnetic materials in the following aspects in recent years was summarized： Sm–Co-RE permanent magnets with high application temperatures, positive temperature coefficients of coercive force, zero temperature coefficients of residual magnetization, high resistance rate,high mechanical property, and nanocrystallization.
基金Project supported by Yunnan Provincial Department of Education(2012Z102)
文摘A Box-Behnken design （BBD） of response surface methodology （RSM） was used to optimize the preparation of the Zn-Sm antibacterial white carbon black by the sol-gel method. The statistical analysis of the results showed that the particle size of the Zn-Sm antibacterial white carbon black was significantly affected by the reaction time, reaction temperature and the stirring speed. According to analysis of variance （ANOVA）, the values of the determination coefficient （R2=0.9821） and the ＂Pred R-Squared＂ of 0.8227 were in reasonable agreement with the ＂Adj R-Squared＂ of 0.9591. It was indicated that this model could be used to navigate the design space. The optimized reaction time, temperature and the stirring speed were 0.88 h, 87.83 ℃, and 473.45 r/rain, respectively. In addition, the bacteriostasis rate of the product was about 97.92%.
文摘The efficiency of activated biochar fibres obtained from Opuntia Ficus lndica regarding me sorpuon oi trlvalent samarium （Sm（Ⅲ）） from aqueous solutions was investigated by batch experiments. The effect of various physicochemical parameters （e.g. pH, initial metal concentration, ionic strength, temperature and contact time） on the Sm（III） adsorption was studied and the surface species were characterized by FTIR spectroscopy prior to and after the lanthanide sorption. The experimental results showed that the acti- vated biochar fibres possessed extraordinary sorption capacity for Sm（Ⅲ） in acidic solutions （qmax=90 g/kg, pH 3.0） and near neutral solutions （qmax=350 g/kg, pH 6.5）, This was attributed to the formation of samarium complexes with the surface carboxylic moieties, available in high density on the lamellar structures of the bio-sorbent.
文摘The solvent extraction of Pr(Ⅲ) and Sm(Ⅲ) with trialkyl phosphine oxide(Cyanex 923) in chloroform,carbon tetrachloride,n-octane,cyclohexane,1,2-dichloroethane,benzene,toluene,xylene and nitrobenzene from acidic nitrate medium was investigated.On the basis of slope analysis data,the composition of the extracted species was determined as(M(NO3)3?2CY923),CY923 refers to Cyanex 923.The values of the equilibrium constants and the separation factors were calculated.The effect of the diluents on the metal extracti...
基金Project supported by National Hi-Tech R&D Program of China(863 Program,2011AA03A409)Major State Basic Research Development Program of China(973 Program,2012CBA01207)
文摘The effects of samarium（Sm） on microstructure and corrosion resistance of AZ92 magnesium alloy were characterized and analyzed by scanning electronic microscopy, X-ray diffraction, mass loss test, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy and potentio-dynamic polarization test. The results showed that the added Sm could promote continuous precipitation of β-Mg17Al12 phase in grains, and meanwhile restrain discontinuous precipitation of the same phase along the grain boundaries. Thus, the precipitations distributed more uniformly in the aged AZ92 magnesium alloys. When the content of Sm was 0.5 wt.%, the corrosion resistance of aged AZ92 alloy tended to be the best, which was due to the β-phase distributes more homogeneous reducing the galvanic corrosion. The corrosion product film had more integrality and compactness than AZ92 alloys without Sm. However, it resulted in worse corrosion resistance of AZ92 alloy because of the formation of mass cathodic Al2 Sm phase coming from excess Sm in AZ92 alloy.
基金Project supported by the China Petroleum & Chemical Corporation (402008)
文摘The effects of samarium(Sm) on carbon-methanation and catalytic activity of the Ba-Ru-K/AC (active carbon) catalyst for ammonia synthesis were investigated. The addition of samarium improved significantly the activity and stability of the catalyst. The results of temperature-programmed desorption (H2-TPD) and in-situ-TPSR FTIR indicated that samarium impeded the adsorption of hydrogen on the catalyst surface, thus leading to the high catalytic activity and resistance to carbon-methanation. XRD patterns reve...
文摘Trivalent samarium ion (Sm^(3+)) activated calcium molybdate (CaMoO_4) phosphor was prepared by solid-state reaction in air. The XRD pattern of the powder CaMoO_4∶Sm shows that the CaMoO_4∶Sm single phase is developed fully through our preparation procedure. The excitation spectrum of CaMoO_4∶Sm is composed of a broad absorption of host and some sharp lines of the f-f transition absorption of Sm^(3+). Illustrated in photoluminescence spectrum, CaMoO_4 doped with Sm^(3+) displays orange red emission that is ascribed to the inner 4f^5 electron transitions ~6H_(7/2)(orange)and ~6H_(9/2)(red)of Sm^(3+). Different from the sites of Sm^(3+) in CdWO_4, the Sm^(3+) ions substitute for the Ca^(2+) and form only one type emission center in the CaMoO_4 crystal lattice.
基金supported by National Natural Science Foundation of China(21346006)National College Students' Innovation and Entrepreneurship Training Major Project(201310222013)+3 种基金the Department of Scientific Research Projects in Heilongjiang Province(B201015)Scientific Research Project in Heilongjiang Province’s Department of Education(125418211254178312543078)
文摘An inorganic nanomaterials combination of Sm, Ag, and TiO2 was synthesized using supercritical fluid drying （SCFD） combined with solgel techniques. The structure, photocatalysis and bacteriostatic activity of the materials were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, X-ray photoelectron spectroscopy （XRPS）, photocatalytic performance, and antibacterial activity experiments. The XRD results showed that the average particle diameter of Sm/Ag/TiO2 was 14.62 nm and Ag and Sm ions were dispersed on the surface of TiO2 in a highly dispersed, amorphous form. The TEM image showed that the size of the particle was 12 nm using the scherer formula. The XPS result showed that the element Sm was doped and Ag was loaded inorganic nanomaterials successfully. Sm/Ag/TiO2 exhibited optimal photocatalytic properties at 600 oC, the photocatalytic optimal proportion of Sm/Ag/TiO2 was 2：2：100. When the molar ratio was 2：2：100, the bacteriostatic circle diameter was 16 mm for Staphylococcus aureus, the minimum bacteriostatic concentration was 200μg/mL for white beads coccus, and the minimum bactericidal concentration was 2×10^4μg/mL for white beads coccus. The SEM results showed that the antibacterial material attached to the candida albicans cell surface, cells appeared fold deformation. Therefore the inorganic nanomaterials Sm/Ag/TiO2 had high temperature resistance, good photocatalytic and antibacterial characteristics in visible light.
基金financially supported by the Aeronautical Science Foundation of China(No.2012ZF53080)the Shaanxi Province Science and Technology Research and Development Program of China(No.2013K08-11)+1 种基金the Fund of the State Key Laboratory of Solidification Processing in Northwestern Polytechnical University(No.SKLSP201009)the 111 Project of China(No.B08040)
文摘The mechanical properties of Al-Cu-Mn casting alloy mainly depend on the morphology, distribution, size, and number ofθ′（Al2Cu） precipitates. In this study, we have analyzed the effect of rare earth samarium （Sm） addition on the kinetics of precipitation in the Al-Cu-Mn casting alloy by using differential scanning calorimetry （DSC） and high-resolution transmission electron microscopy. Thermal ef-fect peaks that are attributed to the formation and the dissolution of Guinier-Preston （GP） zone andθ′phase were identified from the DSC curves. The activation energy ofθ′formation was calculated by using both the Kissinger method and the analytical model, and the corre-sponding results were compared. Results suggest that the activation energy ofθ′formation in Al-Cu-Mn alloy is dramatically higher than that in Al-Cu-Mn-Sm alloy. Accordingly, it is concluded that the addition of rare earth Sm decreases the activation energy ofθ′formation and promotes the formation ofθ′precipitates.
基金Project supported by the National Natural Science Foundation of China (20571020)
文摘Gaseous penetration technique was adopted to improve the electrical conductivity of BaTiO3 powders and the effects of penetration temperature on the structure and electrical conductivity of Sm-modified BaTiO3 powders were studied.It was observed that the penetration of Sm made the resistivity of BaTiO3 powders decrease with the increase in the penetration temperature and decreased to the lowest point of 4.20×102 ？·m when the penetration temperature was 950 oC.The relationship curve of the temperature and resistivity of the samples was also established preliminarily to get the mathematical expression by the fitting method.Through X-ray diffraction （XRD） analysis,the new phases of Sm2O3 and Ba4Ti2O27 were detected.It was indicated that intricate reactions related to Sm took place during the penetration process and led to the Ti-rich state of the system.The Fourier transform infrared （FTIR） spectrum illustrated that the bonds of Ti–O octahedron was strengthened by substitution of Sm3＋ at Ti4＋ sites,which led to the growth of Ti：Ba ratio.The analysis results of scanning electron microscopy （SEM） indicated that the particle size of Sm-modified BaTiO3 powders progressed with the penetration temperature increasing.
基金Project supported by Ministry of Industry and Trade of the Czech Republic
文摘The electrochemical behaviour of samarium was investigated in LiF-BeF2 system on an inert （Mo） electrode by cyclic voltammetry and chronopotentiometry at 804, 833, 847 and 872 K. Redox process Sm3＋＋e–→Sm2＋ was recognized and analysed. Cyclic voltammetry data suggested that at potential sweep rates lower than 0.25 V/s, the reduction was limited by the diffusion of Sm3＋ ions. It was not possible to observe reduction process of Sm2＋＋2e–→Sm0 due to insufficient electrochemical stability of LiF-BeF2. Diffusion coefficients of Sm3＋ ions in LiF-BeF2 were calculated from voltammetric and chronopotentiometric data in the temperature range 804–872 K. Diffusion coefficient values obeyed Arrhenius law. Activation energy was calculated to be 102.5 kJ/mol.
文摘Nanometer crystal samarium borate with a particle size of 20～40?nm was prepared using replacing solvent drying technique. The wear resistance and load carrying capacity of 500SN base oil could be improved and the friction coefficient could be decreased by the addition of nanometer samarium borate. But the dosage of samarium borate nanoparticles had to be controlled at a relatively low level, a higher concentration of nanoparticles was not of beneficial to the tribological performance of the oil. The optimal dosage of nanometer samarium borate is 1.0%. Tribochemical reactions took place in the tribological process, which resulted in the formation of deposition products including diboron trioxide and disamarium trioxide. Fe 2B and FeB were also found on the wear scar. The improvement of tribological properties of the oil comes from the formation of deposition layer and permeating layer. [
基金supported by the National Natural Science Foundation of China (21071101)
文摘A complex [Sm（2-IBA）2（2,2’-bipy）（NO3）]2 （2-HIBA=2-idobenzoic acid; 2,2’-bipy=2,2’-bipyridine） was synthesized by solvent method and characterized by X-ray single-crystal diffraction. The complex crystallized in triclinic crystal system, Pī space group, with a= 0.97873（3） nm, b=1.28124（3） nm, c=1.29174（3） nm, α=108.3740（10）o, β=111.7340（10）o, γ=101.7870（10）o. The complex was the centrosymmetric binuclear molecule, in which two Sm3＋ ions were connected by four 2-IBA ligands. Two of the 2-IBA ligands were in a bidentate bridging mode and the other two were in a tridentate bridging mode. Sm3＋ ion was also coordinated to one chelating NO3– group and one 2,2’-bipy molecule. The 2D supramolecular network formed through weak I…I interactions and π…π stacking interactions. The fluorescent emission peaks at 562, 595, and 642 nm corresponded to the 4G5/2→6F5/2, 4G5/2→6F7/2, and 4G5/2→6F9/2 transitions of Sm3＋ ion, respectively.
基金Project supported by the National Natural Science Foundation of China(51972201)International Science and Technology Cooperation of Science and Technology Department of Shaanxi Province of China(2017KW-024)。
文摘A series of samarium(Sm)doped hydroxyapatites containing strontium(Sr)with controllable and adjustable luminescence were designed and prepared via chemical hydrolysis co-precipitation method.The effects of doping concentration of Sm on the structure,composition,photoluminescence(PL),energy transfer,substitute site,fluoresce lifetime and luminescence color of samples were investigated.It is shown that the introduction of Sr ions induces the structure and composition change for Sm doped samples.The typical transitions of Sm^(3+) at 564,601,648 and 707 nm due to^(4)G_(5/2)→^(6)H_(J/2)(J=5,7,9 and 11)transition under the excitation of 404 nm were detected.The PL intensity is affected by the Sr/Ca ratio and Sm concentration,and the optimal concentration of Sm is 0.8 mol%when Sr/Ca ratio equals 7/3.The non-radiative transitions and energy transfer of Sm ions are the main reason for the quenching,and the interactions among ions are ascribed to dipole-dipole type by theoretical calculation.Besides,the ratio of PL intensity between 601 and 648 nm(r_(O/R)=I_(601nm)/I_(648nm))indicates the symmetry and substitution process of Sm ions to Ca/Sr ions.The fluorescence lifetime(τ)decreases with the concentration of Sm increasing,which is the result of the decrease of distance and the enhanced interaction between Sm ions.The CIE chromaticity coordinates and luminescence color of samples are in the orange-red region and have close relation with the concentration of Sm.Furthermore,the cytotoxicity evaluation and confocal laser scanning microscopy(CLSM)observation of samples via cells indicate the good biocompatibility and safe use of this kind of bio-based luminescent materials for their potential efficient fluorescence labeling and detection.
文摘The polymerization of acrylonitrile initiated by organolanthanide complexes alone is studied for the first time. The effect of polymerization conditions on catalytic activity of the title complex and molecular weight of the polymers produced have been studied.
基金financially supported by the Natural Science Foundation of Jiangsu Province (No.BK2007724)Military Coordination Scientific Research Projects (No.JPPT-1486)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions (No.CXZZ110333)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘A novel 1064 tun laser stealth absorbent of SmzO2S was prepared by flux method. The effects of different calcining temperatures and fluxes on the reflective property of Sm2O2S were investigated. The phase composition, morphology, and reflectivity of the powders were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and ultraviolet-visible spectrophotometer （UVPC）. The results showed that pure phase of Sm202S could be obtained with Na2CO3 as flux above 950~C, and the reflectivity decreased with the calcination temperature increasing. Compared with other samarium compounds, the reflectivity at 1064 nm of Sm2O2S was the lowest. Different fluxes had great impact on the phase composition, particle morphology, and reflectivity of the products. In short, Sm2O2S was suitable as a kind of absorbent against 1064 nm laser.
基金supported by the National Natural Science Foundation of China(51405216,51165032)Jiangxi Province Education Commission Foundation(GJJ14200)
文摘The influence of Sm （Samarium） content on microstructure and mechanical properties of recycled die-cast YLl12 aluminum alloys was investigated. The results show that many small Sm-rich particles form in the recycled die-cast YLl12 alloys with Sm addition. At the same time, the secondary dendrite arm spacing in the YLl12 alloys modified with Sm is smaller than that of the unmodified alloy. The eutectic Si of recycled die- cast YL112-xSm alloys transforms from coarse acicular morphology to fine fibres. Mechanical properties of the investigated recycled die-cast YLl12 aluminum alloys are enhanced with Sm addition, and a maximal ultimate tensile strength value （276 MPa） and elongation （3.76%） are achieved at a Sm content of 0.6wt.%. Due to the modification of eutectic Si by Sm, numerous tearing ridges and tiny dimples on the fractures of tensile samples are observed.
