15 September 2014, Volume 45 Issue 17-稀土
    

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    研究 开发
  • Jianchao He;
    . 2014, 45(17-稀土): 1-0.
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    The composition and the size of nanoparticles in the 9CR-ODS has been investigated by STEM –EDS and Atom probe tomography。According to the Correlation between Y:Ti ratio and nanoparticles size in 9Cr-ODS steel, Three types of nanoparticles were observed including: (a) small sized nanoparticles less than 5nm, Y:Ti<1, indicating non-stoichiometric nanoparticles (b) intermediate sized nanoparticles, ranging from 5 - 40nm, indicating Y2Ti2O7 (c) large sized nanoparticles more than 40nm, indicating TiO2. The nanoparticles was measured by proximity histogram (proxigram) method, exhibiting t a core shell structure with a Y-Ti-O core and a Cr shell.
  • ; ;
    . 2014, 45(17-稀土): 2-0.
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    To investigate the redox property of Ce1-xYxO2-δ (x=0, 0.15, 0.25 YDC) nanopowder, the YDC nanopowder with average crystal size around 12nm was prepared by co-precipitation method. The pH value of Y3+、Ce3+ co-precipitation was studied in aqueous solution by calculation of precipitation equilibrium. Through the O2-TPD study at RT-1000℃, it was found that the oxygen desorption increased at higher initial oxidation temperature as results of oxygen vacancies increment and ceria reduction by Y2O3 doping. The reducing property of YDC was investigated by H2-TPR at 200-1000℃. The Y2O3 dopant enhanced the anti-reducing property of YDC at 450-650℃. While the H2 consumption peak decreased with the Y2O3 dopant increased at 750-950℃, the results suggested the decrease of YDC reducing property. Compared the O-1s and Ce 3d spectrums of XPS results, the peaks of lattice oxygen and oxygen desorption increased with the Y2O3 dopant increased, that showed the oxygen desorption of Ce1-xYxO2-δ nanopowder increased in the heating process. And it was found that Ce4+ was partly transformed to Ce3+ by Y2O3 doping after heat treatment at air or 10%H2/Ar atmosphere.
  • jinxiu wu ;;;
    . 2014, 45(17-稀土): 3-0.
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    The interaction between in the range of 3000 the molecular weight of chitosan(CS ) and bovine serum albumin (BSA)in vitro under simulative physiological conditions was investigated by fluorescence spectrum, ultraviolet- visible absorption spectrometry and three-dimensional fluorescence spectra. It was shown that CS has a quite strong effect in quenching the fluorescence launching and enhance the UV absorption spectra of BSA. The maximum emission peak of BSA shifted to short wave for 8~10nm. After the fluorescence quenching date was analyzed by Stern-Volmer equation, the results indicated that the reaction between bovine serum albumin and CS generated the new complex-system. The quenching belonged to static fluorescence quenching, with non-radiation energy transfer happening within single molecule. The binding constants KA(Kb) and thermodynamics parameters(ΔΗ,ΔS,ΔG) were calculated respectively according to equation of fluorescence spectrometry and ultraviolet spectrometry at different temperatures. Based on thermodynamic data, the main reaction between CS and BSA were electrostatic force, but hydrophobic interaction can not be ignored. The effect of CS on the conformation of BSA was researched by synchronous fluorescence spectrometry and three- dimensional fluorescence spectra, result in some micro-environmental and conformational changes of BSA molecules.
  • Jun-Chi LI;
    . 2014, 45(17-稀土): 4-0.
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    CaBaCo2O5+δ thin films were deposited on (001) LaAlO3 substrates by pulsed laser deposition. The microstructures of the film and substrate were studied by X-ray diffraction (XRD) and of transmission electron microscopy (TEM). Results show that (1) dislocations and twins appear in the LaAlO3 substrates, and the (100) wedge-shaped twin is the main type; (2) CaBaCo2O5+δ thin film is polycrystalline in nature, and the initial grain structure with a grain size of about 5~8 nm during growth is kept at the bottom of the film. While the grain size at the top of the film is larger, about 11~16 nm. Based on the observation results, a growth mechanism of the film was proposed. Possible processes to improve the film quality have also been discussed.
  • Yong-Jun SHEN
    . 2014, 45(17-稀土): 5-0.
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    Sr-doped lanthanum manganite (La1-xSrxMnO3) thermal control ceramics were prepared by Spark Plasma Sintering (SPS) and the effects of sintering temperature as well as Sr doping on crystalline phase, relative density, microstructure, electrical conductivity and emissivity were investigated. With the increasing of sintering temperatue, the density and relative density were increased and single-phased La1-xSrxMnO3 ceramics with a high relative density (>97%) were obtained at 1100?C. The ratio of Mn4+/Mn3+ in the ceramics was increased with increasing Sr doping content, leading to the enhancement in electrical conductivity. With the increasing of temperature, the phase transition from metal to insulator occurred and the infrared emissivity increased, indicating good variable-emittance and high emissivity at the appropriate Sr doping content of x = 0.1.
  • Jiang Tao
    . 2014, 45(17-稀土): 6-0.
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    Abstract: Powder metallurgy technology and high temperature solid phase sintering method are used to prepare 17Ni/(10NiO-NiFe2O4) cermet doped 1% TiO2. The phase composition is analyzed by X-ray diffractometer and microstructure is observed by scanning electron microscope. The influence of 1% TiO2 to density and the high temperature oxidation resistance are studied mainly. The results reveal that TiO2 does not change the structure of cermet. It is helpful to reduce activation energy of diffusion of molecule and accelerates diffusion. Moreover, it improves density which makes granular combine closely. In addition, it also can improve the high temperature oxidation resistance of cermet. After oxidation of 12h at 960℃,the surface of cermet is flat, the oxide particles combine closely and particle size uniform. The increased weight after oxidation is 15 mg/cm2 which is 62.5% of undoped cermet.
  • Chao Li;; ;zhang jiuxing
    . 2014, 45(17-稀土): 7-0.
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    Waste sintered Nd-Fe-B permanent magnets were recycled via NdH nano-particle doping method. Effect of the NdH nano-particle content on the microstructure and magnetic properties of the recycled magnets has been studied. As the NdH nano-particle content increases, the coercivity (Hcj) increases from 11.64kOe to 16.33kOe. The remanence (Br) of about 12.96kGs keeps unchanged and then decreases until additive exceeds 2.0 wt. %. Compared to the properties of the starting scrap sintered magnet, 97.58%, 95.9%,89.7% of Hcj, Br and (BH)max have been recovered in the recycled magnets with 2.0 wt.% NdH nano-particles additive, respectively. Through calculation, the volume of Nd-rich phase increases as NdH nano-particle content increases, and reaches its maximum of 5.7 vol. % for 3.0 wt. % additive. However,grain size of the recycled magnets with 3.0 wt. % additive grow up to 11.68 μm from 8.18μm. It is, therefore, concluded that 2.0 wt. % NdH nano-particle additive is the best content for recovering the properties of the waste magnets.
  • Zhong Qi
    . 2014, 45(17-稀土): 8-0.
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    Preparation and magnetoelectric characterization of Bi0.9Ho0.1Fe1-xMnxO3 ceramics Zhong Qi, Zhang Ming, Deng Haoliang, Wei Jizhou, Hou Yudong, Zhu Mankang, Yan Hui (College of Materials Science and Engineering,Beijing University of Technology,Beijing 100124,China) Abstract: Multiferroic ceramics Bi0.9Ho0.1Fe1-xMnxO3 (x = 0.05, 0.10, 0.15) ceramics were prepared by solid state reaction method. X-ray diffraction (XRD) indicated that Bi0.9Ho0.1Fe1-xMnxO3 ceramics exit secondary phase Bi2Fe4O9. With increasing Mn4+ content, the gradual merging of the (104) and (110) peaks and the gradual disappearance of the (006) peak indicated a structural transition from the rhombohedral to the tetragonal were observed. SEM images indicated that the grain size increases with increasing Mn4+ ions dopant concentration. Ferroelectric performance testing were shown that that all samples present the typical loss unsaturated ferroelectric behavior, as the P-E loops were not saturated. The remnant polarization of Bi0.9Ho0.1Fe1-xMnxO3 (x = 0.05, 0.10, 0.15) ceramics increased and then decreased sharply. The M-H curves recorded at room temperature revealed that the remanent magnetization increased with increasing Mn4+ content. In other words, the unique M-H loops indicated that the Bi0.9Ho0.1Fe1-xMnxO3 ceramics have a metamagnetic transition with increasing magnetic filed.
  • yun LIU
    . 2014, 45(17-稀土): 9-0.
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    The YPO4?nH2O:Eu3+(n=0,0.8) microcrystals were synthesized via hydrothermal process by adjusting the concentration of Eu3+.The X-ray power diffraction (XRD),field emission-scanning electron microscope (FE-SEM) and photoluminescence (PL) were used to study the structure,morphology and luminescence properties.The experimental results indicate that the structure of YPO4 has been changed with the increasing of the concentration of the Eu3+ ions.When the doping concentration of the Eu3+ ions at 13%,the tetragonal phase has been fully converted to the hexagonal phase.The morphology of microcrystal changed from microflakes to bundle-like phase.The luminescence intensities of YPO4?0.8H2O:Eu3+ ware lower than that of YPO4:Eu3+.However,when the powder of YPO4?0.8H2O:Eu3+ have been annealed at 200℃,the luminescence intensities have been greatly improved as the function water has been lost.
  • Chun-mei ZENG
    . 2014, 45(17-稀土): 10-0.
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    Yttrium aluminum garnet(YAG) powders were synthesized by co-precipitation with forward-titration, reverse-titration and parallel flow using NH4Al(SO4)2?12H2O, Y2O3, Nd2O3 as starting materials and NH4HCO3 as precipitant at a high rate of adding the materials. The difference of the processes was discussed and the phase composition, morphology, particle size distribution of the powders were measured. It is found that parallel flow is simple to operate without adjusting pH value. The powders by reverse titration and parallel flow are of pure-phase YAG, while the powders by forward-titration are of major-phase YAG and a trace amount of other phase. The powders by parallel flow are well dispersed with a narrow size distribution, spherical morphology and the highest activity. After YAG ceramics are sintered at 1670 ℃ in vacuum, the transmittance of mirror-polished samples by forward-titration, reverse-titration and parallel flow are 68%, 70%, 75%,respectively.
  • . 2014, 45(17-稀土): 11-0.
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    Er3+ doped tellurite glasses are prepared by a facile melt-quenching technique. The absorption spectra are detected for the with various Er3+ concentrations. The J-O parameters Ωλ are fitted using the Judd-Ofelt theory, and we discuss the effect of Er3+concentrations on the characteristic of tellurite glasses. The up conversion spectra are measured excited with a 980 nm laser. We observe green light (525 nm) and red light (655 nm) at room temperature,which are emitted from the Er3+ transition of 2H11/2→4I15/2 and 4F9/2→4I15/2, respectively. The up-conversion emission is attributed to a two-photon process by analyzing the relationship between the power of the laser and the intensity of up conversion spectra. Moreover, we also discuss the concentration quenching of the samples, and provide the existence of the cross relaxation.
  • Qiong SONG
    . 2014, 45(17-稀土): 12-0.
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    Abstract:The Eu3+-doped Na2O-Nb2O5-SiO2 matrix glass were prepared by the high temperature melt annealing method. The transparent glass ceramics containing nanocrystalline sodium niobate were prepared by the heat treatment of two-stage. Samples were characterized by differential thermal analysis, X-ray diffraction, scanning electron microscope, spectrophotometer and fluorescence spectrophotometer. The results show that Eu3+ -doped matrix glass-ceramics containing has fine crystallinity. Nucleation temperature is 715 ℃, the nucleation time is two hours, crystallization temperature is 950 ℃, crystallization time is two hours. The particle diameter is 40 ~ 50 nanometer by SEM analysis. The transmittance of the glass ceramics can be up to 80% in the visible area. Fluorescence spectra showed that the glass-ceramics has strong emission peak at 614 nanometer by the excitation wavelength 393 nanometer. The glass-ceramics is improved greatly compared to the martix glass.
  • Han-Song Xue;;
    . 2014, 45(17-稀土): 13-0.
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    Continuous ultrasonic treatment was introduced into the solidification of the Mg-6Zn-0.5Y magnesium alloy with the power of 0, 300, 600, 900W, respectively. The effect of ultrasonic power on microstructure and mechanical properties of Mg-6Zn-0.5Y magnesium alloy were investigated through micrograph, X-ray diffraction analysis (XRD) and Scanning electron microscope (SEM). The results showed that with the application of 600W ultrasonic treatment, the primary α-Mg phases were transformed from coarse dendrites to fine equiaxed grains, and the semicontinuous quasicrystalline phases at α-Mg boundaries were modified into discontinuous. Besides, the Mg-6Zn-0.5Y magnesium alloy prepared with 600W ultrasonic treatment exhibited the best ultimate tensile strength and elongation. Compared to the untreated alloy, the ultimate tensile strength and elongation are improved by 67%, 56%, respectively.
  • . 2014, 45(17-稀土): 14-0.
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    ABSTRACT: By pulsed laser deposition(PLD), Hf0.2Zr0.8O2(HZO)thin films were fabricated on Pt/Ti/SiO2/Si substrates under different temperatures and oxygen pressures respectively. The impact of the technical conditions on the films’ structural and ferroelectric properties was studied. The films were characterized by X-ray diffraction (XRD) and Radiant RT66A. The results figured that, the ferroelectric polarization was resulted from the impact of the orthorhombic phase HfO2-ZrO2(111) and tetragonal phase ZrO2(002). 18Pa, 500℃ were the optimized parameters of the Hf0.2Zr0.8O2 films on Pt/Ti/SiO2/Si. On the optimized condition ,the film’s 2Pr was 4μC/cm2.
  • Fan-Fei WANG
    . 2014, 45(17-稀土): 15-0.
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    With sol-gel method, Ce3+-doped TiO2 sol was synthedized using tetrabutyl titanate as the former body, anhydrous ethanol as the solvent, glacial acetic acid as the inhibitor, and concentrated nitric acid as the catalyst. The gel was calcined at different temperature 3h, then different amount of Ce3+-doped TiO2 powders were obtained. Different amount of Ce3+-doped TiO2 powders were characterized With XRD .And the results were compared. Used methylene blue as the simulation of organic dyes, the photoactivity impact of samples with different amount of Ce3+-doped was studied under ultraviolet light. As a result, the photoactivity of Ce3+-doped TiO2 is superior to the pure one. When 1.0% Ce3+-doped, heat treatment temperature was 650℃,the photoactivity of Ce3+-doped TiO2 is highest in all samples.
  • Wang-Dong Liu ;;
    . 2014, 45(17-稀土): 16-0.
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    NaYF4:Yb3+, Er3+ ultrathin nanocrystals with average diameter ~3nm were successfully synthesized by hydrothermal method. The fluorescent spectra indicate that the sample emits single-red band light with impurity emission lower than 1/98.6. the mechanism analysis indicates that the size-effect leads to the the surface high energy oscillation phonons and high scattering probability of excitation photons,which leads to the depopulation probability of 4F7/2 states to 4S3/2 and 2H11/2 states decreases greatly while the4F7/2+4I11/2—2*2F9/2 transition was remarkalbly enhanced. As a result, the intense red emission was realized.
  • . 2014, 45(17-稀土): 17-0.
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    NiCoCrAlY laser cladding coatings were prepared on TC4 alloy by laser cladding technology. Influence of different contents of nano-La2O3 particles on quality of coatings was investigated. Morphology, microstructure and micro-hardness of the laser cladding coatings with 0%, 1%, 2% and 3% nano-La2O3 were investigated by means of metallographic microscope, SEM and micro-hardness tester. The result indicated that with the content of nano-La2O3 increasing, dilution rate of cladding layers decreased gradually. The growth of dendritic crystal was inhibited, and the formation of dendritic crystal accelerated. Branch of dendritic crystal was aggravated and the space of with secondary dendritic crystal was decreased, which caused that the grain was refined, and the flower-like grain appeared in the cladding coating. The micro-hardness of cladding layers with nano-La2O3 is higher than without nano-La2O3, and the micro-hardness of cladding layers decreased gradually with the increase of content of nano-La2O3.
  • ; ;
    . 2014, 45(17-稀土): 18-0.
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    Pb(Zr0.52Ti0.48)O3(PZT) thin films were successfully prepared by sol-gel on LaNiO3/Si and Pt/Ti/SiO2/Si substrates. The effects of LaNiO3 (LNO) and Pt bottom electrodes on microstructures and electrical properties of PZT films were discussed. X-ray diffraction (XRD) analysis shows that PZT/LNO films is preferred highly (100) orientation, while PZT/Pt orients (100) and (111). This result means electrodes have effects on the growth-orientations of PZT films. Meanwhile, the grain size of PZT/LNO films is more uniform than that of PZT/Pt films. It is observed that the remnant polarizations of PZT/LNO and PZT/Pt films are 24.4 μC?cm-2 and 15.3μC?cm-2, and the average corresponding coercive field are 130.90 kV?cm-1 and 243.23 kV?cm-1, respectively. Their relative dielectric constants are 1125 and 453 at the frequency of 1 kHz. The leakage currents of PZT/LNO and PZT/Pt films are about in the order of 10-5 and 10-2 magnitudes at an applied electric field of 100 kV?cm-1. The ferroelectric fatigue is also improved by using LNO bottom electrode. These results show that PZT/LNO thin films has better ferroelectric and dielectric properties, which could provide a widely application in ferroelectric and dielectric devices.
  • 工艺 技术
  • ;;;;
    . 2014, 45(17-稀土): 19-0.
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    Dy3+ doped SrMoO4 yellow-emitting phosphors were synthesized rapidly by microwave radiation method. The phase structure and luminescence properties of as-synthesized SrMoO4: Dy 3+ were characterized and investigated by X-ray diffraction and fluorescence spectrophotometer, respectively. The results indicate that the obtained products are pure monazite type molybdates with tetragonal system, belonging to space group I41/a. The excitation spectrum consists of a broad band in range of 200~340 nm and a series of sharp peaks between 340 nm and 500nm. The broad band with a maximum at 284nm is ascribed to the charge-transfer band (CTB) between Mo-O and Dy-O; the sharp peaks belong to f-f transition of Dy3+. The emission spectrum contains two narrow bands: the narrow band with main peak at around 576 nm originated from the electric dipole transition of 4F9/2→6H13/2 of Dy3+, and the other at around 480 nm originated from 4F9/2→6H15/2 transition of Dy3+. The intensity of the former is much stronger than that of the latter, therefore, the samples show yellow emitting under the excitation of ultraviolet light. Meanwhile, the influences of doped-Dy3+ concentration and reaction time on luminescent properties of as-prepared samples were also discussed.
  • ;;
    . 2014, 45(17-稀土): 20-0.
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    The non-linear relationship between the magnetostrictive strain and magnetic field intensity will affect the precision and stability of the actuator. This paper tries to reduce the eddy current loss in the Terfenol-D rod to improve linearity by machining radial grooves in the surface of the rod. The Terfenol-D rod is extremely difficulty to machine because of its brittleness. Wire-electrode cutting and precision grinding are preliminary chosen for the slotting, and the experimental results show that although the flake pits will be produced in the machining surface of wire-electrode cutting, the magnetostrictive property of Terfenol-D rod slotted is less affected comparing with precision grinding. The tests of the magnetostrictive strain in the Terfenol-D rod show that the eddy current loss is reduced and the linearity of output displacement is significantly improved by slotting 4 radial grooves in the rod surface.
  • xing wang ;
    . 2014, 45(17-稀土): 21-0.
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    The thermal barrier coatings made by different preparing process have different micro-structure, the quartet structure generation set (QSGS) has been proposed to generate the micro-structure of isotropic and anisotropy thermal barrier coatings, the anisotropy model contain layered structure and columnar structure. The composite’s heat conductivity analysis program was developed by using the thermal resistance network method; the numerical calculation of the thermal conductivity of the three structures has been simulated. This method has been used to solve the paralleled and series model of the composites, the result match with the theory solution fairly good. The calculation results show: increasing the porosity of the coating is an effective way to improve the heat insulation ability; the pore diameter makes no significantly difference to the thermal conductivity of the coatings; the layered structure is superior to the columnar structure in heat insulation.
  • ;Yu-Fei TANG ;;Kang Zhao
    . 2014, 45(17-稀土): 22-0.
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    Tubular ZrO2/SUS316L gradient materials with gradient changes of 10vol.% and 20 vol.% were fabricated by tape casting-roll technology. Processing of gradient materials was optimized. Morphologies of cross-sections were characterized. Radial compression and thermal shock behaviors of tubular gradient materials were analyzed by finite element analysis combination of mechanical tests and cyclic thermal shock tests. Results showed that: ZrO2/ SUS316L gradient materials with graded components at interlayer are obtained. Maximum tensile stress generate in the outer wall when radial compression of tubular gradient material. With the composition change was 20 vol.%, deformation resistance of tubular gradient material increased and the fracture energy decreased that compared to the 10vol.% of the composition change. Thermal shock behavior of tubular gradient material was increased with composition changes decreased, and the maximum number of thermal shock cycle is 78 from 500 to 25oC when the composition change is 10vol. %.
  • . 2014, 45(17-稀土): 23-0.
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    Y-TZP/ LZAS glass-ceramic gradient coatings on Q235 steel substrate were designed in order to improve the toughness of glass-ceramic coatings . The effects of the the number of graded layers, coating thickness and the volume difference of 3Y-TZP between layers on the residual stress were analyzed by using finite element software. The results show that radial compressive stress is distributed on the surface of graded coatings. There are clear stress concentration in the coating/substrate interface edge. The layer numbers, the coating thickness, and the volume difference of 3Y-TZP between layers have an important influence on radial stress, axial stress and shear stress in the coating/substrate interface. Y-TZP/ LZAS glass-ceramic gradient coatings were fabricated on the Q235 steel substrate via slurry methord. The residual stress of gradient coatings were measured by X-ray diffraction approach to verify the reliability of the simulation.
  • . 2014, 45(17-稀土): 24-0.
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    The Bridgman growth and spectral properties of fluoride laser crystal Yb3+: LiYF4 are reported in this paper.According to the molar ratio of LiF: YF3: YbF3 = 51.5: 47.5: 1.0, the anhydrous polycrystalline material for Yb3+:LiYF4 crystal growth was synthesized by means of the fluoridation process under dried HF atmosphere at elevated temperature. A series of Yb3+: LiYF4 single crystals with 12 mm in diameter were grown successfully by means of vertical Bridgman method under the sealed non-vacuum atmosphere. The dopant concentration and spectral properties of as-grown crystals were characterized by means of chemical analysis and spectroscopic measurements respectively. It was confirmed that Yb3+ ions had been doped into LiYF4 host crystal with effective segregation coefficient estimated to be 0.455. The single crystals exhibit a high optical transmittance in a wide wavelength range from ultraviolet to infrared region. Under the photonic excitation at 896 nm, the single crystals possess a fluorescence emission at the wavelength ranges from 930 to 1030 nm with decay life time of 1888 μs.
  • . 2014, 45(17-稀土): 25-0.
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    Abstract:In order to increase anti-high temperature oxidation properties of 3D-Cf/SiC composites, oxidation resistant coatings, including a chemical vapor deposition (CVD) SiC bonding layer, a self-sealing active layer and a CVD-SiC erosion resistant layer, were prepared on carbon fiber reinforced silicon carbide (3D-Cf/SiC) composites by CVD and powder sintering technology. TG, SEM and TEM were used to research self-sealing mechanism of the coating. The results show that the self-healing mechanism of the coating is mainly that flowing glass phases oxidized of B4C and MoSi2 fill in material cracks and pores, and block off the passage of oxygen at high temperature. So 3D-Cf/SiC composites have good high temperature oxidation resistance properties.
  • 综述 进展
  • . 2014, 45(17-稀土): 26-0.
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    Abstract: Oxide semiconductor gas sensor possesses exceptional properties such as high sensitivity, low cost, simple method of measurement and convenience of use, which has great utilization potentiality in the aspect of the real-time detection of toxic and harmful gases. In this paper, the research progress, the existing problems, and the development trends of modified metal oxide semiconductor gas sensor was summarized.
  • 工艺 技术
  • Jin-Bo Fan;Y.G. Chen
    . 2014, 45(17-稀土): 27-0.
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    Replacement process has been used on the surface of Gd to form a layer of film-nickel, and the structure and thickness has been analyzed by using optical microscope (OM), X-ray diffraction (XRD), scanning electron microscope (SEM) and energy spectrometer (EDS). The result shows that the coating organization of the film is single with the thickness about 15 um. In addition, by measuring the potentiodynamic polarization curves and weightlessness experiment before and after the plating nickel materials in deionized water corrosion performance, the results show that the material after the plating nickel of corrosion potential increased from 0.9247 V to 0.7784 V, the corrosion current density of 0.0019 mA?cm-2 slightly reduce to 0.00057 mA?cm-2. Compared with the pure Gd, the average corrosion rate is reduced by 3.5 times after nickel plating.
  • 综述 进展
  • ;
    . 2014, 45(17-稀土): 28-0.
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    Abstract: In this review, research progress about the intelligent light responsive controlled release of polymer micro/nano particles has been described, which is paid more attention at the present stage. In detail, intelligent light responsive microspheres, optical responsive porous materials and multiple responsive materials based on light response were respectively introduced. At last, the light responsive gel in the future research direction is prospected.
  • Jun SHEN
    . 2014, 45(17-稀土): 29-0.
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    The chemically active magnesium possesses a strong electronegativity and standard potential of -2.37 V. Therefore, the corrosion resistance of magnesium alloys has been one of the critical bottlenecks preventing their wide applications. In recent years, as the corrosion mechanism of magnesium alloys has been researched in depth, enormous new solutions and craft-processes have been proposed. From the two aspects of physical and chemical anticorrosion, this paper provides a thorough summary about research progress of main anticorrosion methods and mechanism of magnesium alloys in order to promote their development and application.
  • 研究 开发
  • Xiao-Ni LIU
    . 2014, 45(17-稀土): 30-0.
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    Merrifield chitson resin-supported cyclen (MCRC) was prepared by attaching 1,4,7,10-tetraazacyclododecane (cyclen) to Merrifield chitson resin (MCR). Then coordination with Ce(Ⅲ) as catalytic center to be MCRC-Ce(Ⅲ). Ninhydrin reaction, SDS-PAGE,HPLC, as well as automatic amino-acid analyzor were drawn to investigate the hydrolyzing ability of MCRC-Ce(Ⅲ) toward BSA. The results indicated that after 24 hours, BSA can be hydrolyzed up to 88% at physiological pH, 60℃,where protein was hydrolyzed into smaller peptides and amino acids, and the pseudo-first-order kinetic constant (Kobs) was 7.05×10-2M*h-1. MCRC-Ce(Ⅲ) has a strong binding affinity with metal ions, which could be reused for 6 times while the catalytic ability maintains 80% of the original, indicating that MCRC-Ce(Ⅲ) has a broad application prospect.