J.H.Dong 1)
,
J.Y.Chen 2
,
3) and. C.N.Cao 1) 1) State Key Laboratory for Corrosion and Protection of Metals
,
Institute of Corrosion and Protection of Metals
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China 2) The International Center for Materials Physics
,
CAS
,
Shenyang 110015
,
China 3) Shenyang Normal College
,
Shenyang 110031
,
China
金属学报(英文版)
The effect of chloride ion on the corrosion inhibition of iron caused by dencylamine(DA), dipentylamine(DDA) and dodecylamine(DPA) has been investigated by measuring the inhibitory coefficients for the anodic and cathodic processes at corrosion potential. It has been shown that the major synergistic inhibition effects between amines and chloride ions occur in the cathodic process, very weak in the anodic process. The anodic inhibition mechanism follows the competing adsorptive model, while the cathodic inhibition mechanism follows the cooperative adsorptive model.
关键词:
synergistic inhibition
,
null
,
null
Condensed Matter Physics
The (63)Cu Knight shifts and g factors for the normal state of YBa(2)Cu(3)O(7) in tetragonal phase are theoretically studied in a uniform way from the high (fourth-) order perturbation formulas of these parameters for a 3d(9) ion under tetragonally elongated octahedra. The calculations are quantitatively correlated with the local structure of the Cu(2+) (2) site in YBa(2)Cu(3)O(7). The theoretical results show good agreement with the observed values, and the improvements are achieved by adopting fewer adjustable parameters as compared to the previous works. It is found that the significant anisotropy of the Knight shifts is mainly attributed to the anisotropy of the g factors due to the orbital interactions.
关键词:
electron paramagnetic resonance;nuclear magnetic resonance;Knight;Shift;(63)CU;YBa(2)Cu(3)O(7)
Communications in Theoretical Physics
With the strong-field scheme and cubic bases, the complete d(3) energy matrix in a tetragonally distorted cubic-field has been constructed. By diagonalizing this matrix, the energy spectra of SrTiO3:Cr3+ and SrTiO3:Mn4+ at normal pressure and various temperatures have been calculated. Correspondingly, the FORTRAN program calculating the g factor of the ground state has been worked out. By using the program and the wave function obtained from diagonalizing the complete energy matrix, the g factors of the ground state of SrTiO3:Cr3+ and SrTiO3:Mn4+ at normal pressure and room temperature have been evaluated. The calculated results are in good agreement with the optical spectral and EPR experimental data. The comparison and analysis of the results of two crystals have been made. It is demonstrated that the covalency of the bonding between Mn4+ and ligands (O2-) in SrTiO3:Mn4+ is stronger than the one of the bonding between Cr3+ and ligands (O2-) in SrTiO3:Cr3+. It is shown that the obtained wavefunctions and values of parameters are reasonable.
关键词:
crystal fields;energy spectrum;optical properties;g factors;covalency;ruby
Chinese Science Bulletin
A study was carried out in order to investigate the effect of contaminants and meteorological variables on the rust layer of carbon steel exposed in Shenyang urban atmosphere. Seven kinds of contaminants and twelve kinds of meteorological parameters were also registered in order to correlate the data with respect to corrosion rate and the stepwise multiple regression analysis was carried out in order to obtain the best regression model. The sum of rainfall time as well as sunshine time and the concentration of H(2)S could stimulate initial atmospheric corrosion of carbon steel. The initial atmospheric corrosion kinetics of carbon steel was observed to follow the cubic equation. The corrosion products were analyzed by XRD and the transformation of phases in different periods was discussed.
关键词:
contaminants;meteorological parameters;carbon steel;urban atmospheric;corrosion;stepwise multiple regression;corrosion products;rust;pollution
Communications in Theoretical Physics
With the strong-field scheme and trigonal bases, the completed d(3) energy matrix in a trigonally distorted cubic-held has been constructed. By diagonalizing this matrix, the normal-pressure energy spectra and wavefunctions of GSGG:Cr3+ at 70 K and 300 K have been calculated without the electron-phonon interaction (EPI), respectively. Further, the contributions to energy spectra from EPI at two temperatures have also been calculated, where temperature-independent terms of EPI are found to be dominant. The sum of aforementioned two parts gives rise to the total energy spectrum. The calculated results are in good agreement with all the optical-spectral experimental data and the experimental results of g(parallel to)(R-1) and g(perpendicular to)(R-1). It is found that the contribution from EPI to R-1 line of GSGG:Cr3+ with taking into account spin-orbit interaction (H-so) and trigonal field (V-trig) is much larger than the one with neglecting H-so and V-trig, and accordingly it is essential for the calculation of the EPI effect to take first into account H-so and V-trig. The admixture of base-wavefunctions, \t(2)(3) E-2] and \t(2)(2) (T-3(1))e T-4(2)), the average energy separation Delta = (E) over bar [t(2)(2)(T-3(1))e(4)T(2)] - (E) over bar [t(2)(3) E-2] and their variations with temperature have been calculated and discussed.
关键词:
crystal fields;optical properties;spin-orbital interaction;electron-phonon interaction;coupling beween t(2)(2)(T-3(1))e(4)T(2) and;t(2)(3) E-2;tunable laser crystal;theoretical calculations;garnet crystals;induced shifts;cr3+ ions;cr-3+;field;ruby;luminescence;spectroscopy;photoluminescence
Y.T. Liu
,
X.J. Guan
,
X.M. Shen
,
X.F. Ma
,
L.J.Wang
,
null
,
null
,
null
,
null
金属学报(英文版)
The microstructures and their kinetics of normal
grain growth are simulated using different Monte Carlo (MC)
algorithms. Compared with the relative figures and the theoretical
normal grain growth exponents of n=0.5, the effects of some
factors of MC algorithm, i.e. the lattice types, the methods of
selecting lattice sites, and the neighbors selection for energy
calculations, on the simulation results of grain growth are studied.
Two methods of regression were compared, and the three-parameter
nonlinear regression is much more suitable for fitting the grain
growth kinetics. A better model with appropriate factors included
triangular lattice, the attempted site randomly selected, and the
first and second nearest neighbors for energy calculations is
obtained.
关键词:
Grain growth
,
null
,
null
Yang LUO
材料科学技术（英文）
Due to continued growth in key markets, a broadening of application base and performance improvements, the market demands of NdFeB magnet increased steadily in 1998, and the global output of sintered NdFeB magnet exceeded 10,000 t, in spite of the economic recession in Asia. In 1998 China produced 3,850 t sintered NdFeB block magnet, with an annual growth rate of +22% over the output in 1997.
关键词:
Applied Physics Letters
The magnetocaloric effect (MCE) at the antiferromagnetic (AF) to ferromagnetic (F) phase transition in Mn1.05Ni0.85Ge and CrO1.86F0.14, and the MCE at the F-AF transition in Tb3Co have been investigated. Mn1.05Ni0.85Ge and CrO1.86F0.14 are found to exhibit the inverse MCE whereas the MCE of Tb3Co is normal. For these compounds, the dependence of the transition temperature on the applied magnetic field B has been studied. A thermodynamical analysis is presented of the sign of the magnetic-entropy change in these three compounds which are representatives of two different types of B-T diagrams. Other possible B-T diagrams are discussed and the analysis is extended to AF-F and F-AF phase transitions reported in literature. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4729122]
关键词:
