R. Mohammadpour A. Iraji zad N. TaghaviniaM. Rahman M.M. Ahadian
材料科学技术（英文）
In this work, the influence of an externally applied bias on photocatalytic performance of crystallized TiO2/Ti nanotubular electrode that formed by anodization in fluoride-based electrolyte were investigated and compared to the behavior of multiporous TiO2 electrode. The photoelectrocatalytic oxidation behavior of methanol over the nanotubular electrode has been studied by measuring photocurrent response, potentiodynamic polarization spectroscopy and using electrochemical impedance spectroscopy (EIS). It was found that the photoelectrocatalytic oxidation and the charge transfer rate constant of reaction on TiO2/Ti nanotubular electrode can significantly be increased by applying electrochemical bias. Moreover, based on our results we have found that the nanotubular TiO2 electrodes have considerably better performance in comparison with porous samples in photoelectrocatalytic performance
关键词:
TiO2 nanotube
,
Photoelectrocatalyst
,
Electrochemical impedance spectroscopy
,
Methanol
杨慧芬
,
唐琼瑶
,
王传龙
,
张露
,
李甜
中国有色金属学报
为考察红城红球菌(Rhodococcus erythropolis,R. erythropolis)作为赤铁矿捕收剂使用的可能性及效果,对R. erythropolis形貌、细胞壁成分及其吸附前后赤铁矿、石英表面电性、疏水性进行分析,对赤铁矿、石英单矿物以及赤铁矿与石英矿1:1(质量比)混合矿进行浮选实验,对其在赤铁矿表面的吸附状况及吸附机理进行研究.结果表明,杆状R. erythropolis表面既含有非极性基团,又含有极性基团,使得其表面具有较高的负电性和较强的疏水性,因而对赤铁矿的吸附作用明显大于对石英的吸附作用.当以此细菌为捕收剂、在溶液 pH 值为6、R. erythropolis用量为75 mg/L时,赤铁矿的回收率为89.68%,而石英的回收率仅为26.25%.混合矿经过一次浮选,可获得铁品位和回收率分别为50.08%和76.41%的铁精矿.R. erythropolis在赤铁矿表面发生复杂的化学吸附且使赤铁矿颗粒形成疏水絮团,从而证实R. erythropolis可作为赤铁矿的捕收剂使用.
关键词:
R. erythropolis
,
微生物
,
赤铁矿
,
石英
,
吸附
,
絮团
,
捕收剂
Solid State Communications
Samples with composition R2Fe14M3 (M = Ga and Si; R = Y, Nd, Sm, Gd, Tb, Dy, Ho, Er and Tm) have been prepared by are-melting. Crystal-structure studies have shown that the prepared samples are single phase with the rhombohedral Th2Zn17 and/or the hexagonal Th2Ni17 structure. Substitution of Ga for Fe in R2Fe17 leads to an increase of the unit-cell volume, whereas Si substitution reduces the unit-cell volume. The Curie temperatures of the R2Fe14Ga3 and R2Fe14Si3 compounds are much larger than those of the corresponding R2Fe17 compounds. The Fe moment decreases upon Ga or Si substitution. The compounds R2Fe14Ga3 and R2Fe14Si3 With R = Er and Tm exhibit a spin-reorientation transition at low temperature. (C) 1997 Elsevier Science Ltd.
关键词:
neutron-diffraction;solid-solutions;substitution;anisotropy;nd2fe17
HL. Huang
,
J.H Xing
,
G.L. Liu and G.Y Zhang(Department of Electrouic Science and Engineering
,
Liaoning University Shenyang 110036
,
China)(Department of Physics
,
Liaoning University Shenyang 110036
,
China)(Shenyang Polytechnic University Shenyan 110023
,
China)(Northeast Microelectronic Institute of Ministry of Electronic Industry Shenyang 110032
,
China)
金属学报(英文版)
The electronic structures of (CdSe)n/(ZnSe)m strained-lager soperfattice (SLS) were investigated by the recursion method in the tight-bindiop opproximation. The total,local, and partial density of states were calculated for n=1, m=5.The total density of states (TDOS) for bulk CdSe, ZnSe and n=1, 3, m=1, 3, 5, for SLS were investigated.Fermi energy, the band gap, the valence of an atom, and the ionization potential and the electron affinity were discassed.
关键词:
density of state
,
null
,
null
,
null
,
null
自然科学进展﹒国际材料（英文）
The phase relations at the 600 degreesC and 700 degreesC isothermal sections of the ternary systems R-Co-B for R Nd, Pr and R = Sm, Cd respectively were summarized in this paper. For Rm+nCo5m+3nB2n, two new types of compounds R3Co13B2 ( R = Pr, Nd, Sm, Gd, Dy, Ho, Er, Y) (m = 2, n = 1) and R5Co19B6 (R = Pr, Nd) (m = 2, n = 3) were synthesized by utilizing the principle of structural combination. Their crystal* structures and easy magnetization direction were determined by X-ray powder diffraction, and structures were refined by the Rietveld method. The Curie temperature T-C, saturation magnetization M-s and anisotropic field H-A of the new compounds were measured using a vibrating-sample magnetometer, an extraction sample magnetometer and M(H) - H curves of samples in different magnetization directions respectively. The T-C and M-s of Rm+nCo5m+3nB2n increase with increasing values of m at a given n value. H-A increases with an increase in n when m is kept invariable. The effects of the substitution of Ni for Co on the magnetic properties of Nd13Co15-xNixB2 were also investigated. It was found that T-SR decreased monotonously as the concentration of Ni increased, and at x = 3 the easy magnetization direction becomes axial at room temperature. The relations between crystal structure and magnetic properties of Rm+nCo5m+3nB2n and the possible routes of synthesizing permanent magnetic materials are also discussed.
关键词:
R-Co-B ternary systems;R3Co13B2;P5Co19B6;crystal structure;magnetic;properties;co-b;phase relation;permanent-magnets;nd;borides;sm;gd;fe
Y.B. Hou
金属学报(英文版)
In this paper, the PMMA films doped with N,N'-diphenyl-N,N'-di(m-tolyl)-benzidineand rubrene were fabricated by spin coating, and the effect of photooxidation onthe photoluminescence of the doped PMMA thin films was investigated. The resultsshowed that under the irradiation of 350nm UV light, N,N'-diphenyl-N,N'-di(m-tolyl)-benzidine can sensitized rubrene and results in the enhancement in the photooxrationof rubrene. The effect of photooxidation on the photoluminescence from rubrene w asmore obvious. Both lifetime measurement and in situ measurement of photolumines-cence showed that rubrene molecules exist in two chemical surroundings.
关键词:
photoluminescence
,
null
Journal of Physical Chemistry A
The density functional method with relativistic effective core potential has been employed to investigate systematically the geometrical structures, relative stabilities, growth-pattern behaviors, and electronic properties of small bimetallic M(2)Au(n) (M = Ag, Cu; n = 1-10) and pure gold Au(n) (n <= 12) clusters. The optimized geometries reveal that M(2) substituted Au(n+2) clusters and one Au atom capped M(2)Au(n-1) structures are dominant growth patterns of the stable alloyed M(2)Au(n) clusters. The calculated averaged atomic binding energies, fragmentation energies, and the second-order difference of energies as a function of the cluster size exhibit a pronounced even odd alternation phenomenon. The analytic results exhibit that the planar structure Ag(2)Au(4) and Cu(2)Au(2) isomers are the most stable geometries of Ag(2)Au(n) and Cu(2)Au(n) clusters, respectively. In addition, the HOMO-LUMO gaps, charge transfers, chemical hardnesses and polarizabilities have been analyzed and compared further.
关键词:
effective core potentials;transition-metal atoms;density-functional;theory;photoelectron-spectroscopy;molecular calculations;silver;clusters;fluorescence spectroscopy;polarizability;anions;adsorption
Journal of Applied Physics
Using the full potential linearized augmented plane wave method based on the spin density functional theory, we investigate the ferromagnetic properties, the electronic structure, and the formation energy of Ga(0.9375)M(0.0625)N (M=vacancy, Ca). The calculations indicate that both cases prefer ferromagnetic ground state. The magnetic moments mainly come from the N atoms surrounding the defect centers, which are different from the conventional diluted magnetic semiconductor. High formation energy for the Ga vacancy Suggests that the defect concentration is too low to result in the ferromagnetic GaN. The formation energy for the two substitutional (Ca(Ga),Ca(N)) and two interstitial sites (tetrahedral T, Ca(i-T) and octahedral O, Ca(i-O)) doped configurations indicates that Ca prefers the substitutional Ga in GaN. The defect concentrations for the Ga(0.9375)Ca(0.0625)N under thermal equilibrium N-rich and N-realistic growth conditions are also discussed, respectively. The calculations show that defect concentration under N-rich condition can readily reach 7%, while under N-realistic growth condition, the maximum defect concentration is as low as 1.71% when the growth temperature increases to 1100 K (melting point of GaN). These results suggest that it would be a little difficult to achieve ferromagnetic state for Ga(0.9375)Ca(0.0625)N using the chemical-equilibrium fabrication method, such as chemical precipitation. Using the same method as that for Cu-doped ZnO [L. H. Ye et al., Phys. Rev. B 73, 033203 (2006)], the transition temperature of Ga(0.9375)Ca(0.0625)N may be close to room temperature. (C) 2008 American Institute of Physics.
关键词:
generalized gradient approximation;doped zno;gan;semiconductors;calcium;systems;origin
