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1.
The grain boundary is an interface and the surface tension is one of its important thermodynamic properties. In this paper,
the surface tension of the ∑9 grain boundary for α-Fe at various temperatures and pressures is calculated by means of Computer
Molecular Dynamics (CMD). The results agree satisfactorily with the experimental data. It is shown that the contribution of
entropy to surface tension of grain boundary can be ignored.
The project supported by the National Natural Science Foundation of China and the Science Foundation of Chinese Academy of
Sciences. 相似文献
2.
Noritaka Mizuno 《Catalysis Surveys from Japan》2001,4(2):149-154
The Keggin-type di-iron-substituted silicotungstate, -SiW10{Fe(OH2)}2O38
6– (I), was synthesized by the reaction of the lacunary [-SiW10O36]8– with Fe(NO3)3 in an acidic aqueous solution and isolated as the tetra-n-butylammonium salt (TBA-I). It was characterized by various analyses and the structure with the oxo-bridged di-iron site was clarified. TBA-I was stable and catalyzed selective oxidation of various alkanes and alkenes with hydrogen peroxide: cyclohexane, adamantane, n-hexane, and n-pentane were catalytically oxidized. Even lower alkanes such as methane, ethane, propane, and n-butane were catalytically oxidized. It was remarkable that the efficiency of hydrogen peroxide utilization to oxygenated products reached up to ca. 100% for the oxidation of cyclohexane and adamantane. Alkenes were mainly epoxidized with hydrogen peroxide. It was demonstrated that the TBA-I showed high turnover number of 135–147 for the oxidation of cyclohexane with 1 atm oxygen. 相似文献
3.
The spring-defect model developed by us in the accompanying paper I to discuss ferroelasticity, exhibited in the BCT phase
of α-iron (BCC metals), is used to analyse anelastic relaxation across the paraelastic to ferroelastic phase transition. The
kinetics of the underlying Hamiltonian representing strain-strain interactions is treated within mean-field theory. The relaxation-response
relation of the linear response theory is employed to derive explicit expressions for the anelastic strain, the frequency-dependent
compliance and the internal friction in terms of the basic parameters of the spring-defect model. 相似文献
4.
In this paper, the stability of various atomic configurations containing a self-interstitial atom (SIA) in a model representing α-iron is investigated. From the energy panorama maps of the SIA located in possible non-equivalent interstitial sites, six relatively stable self-interstitial sites are found, whose structures and formation energies have been described and calculated using the modified analytical embedded atom method and molecular dynamics. The simulation results indicate that the [110] dumbbell interstitial is the energetically most favorable configuration, which is in good agreement with the experimental and ab initio results, and the distances between two displaced atoms that compose the [100], [110] and [111] direction dumbbells have been computed to be 0.68a, 0.65a and 0.29a, respectively, not all being about 0.75a apart. The relaxed displacements up to the fifth-nearest-neighbor atoms around the SIA in O interstitial position are also calculated. 相似文献
5.
《Analytical letters》2012,45(9):761-767
Abstract By shaking aqueous cyanide solution with nitrobenzene contained sulfur, thiocyanate is formed and is extracted into the nitrobenzene as an ion pair of thiocyanate anion and tris-(1,10-phenanthroline)-iron(II) chelate cation. By measuring the color intensity of the organic phase at 516 nm, cyanide is determined spectrophotometrically. A linear calibration curve is obtained up to 4 × 10?5M of cyanide in the aqueous phase. 相似文献
6.
M. Podsiadla J. Rzeszotarska M. K. Kalinowski 《Monatshefte für Chemie / Chemical Monthly》1994,125(8-9):827-831
Summary The solvatochromic behaviour ofbis-(cyano)-bis-(9,10-phenanthroline)-iron(II) has been reexamined spectrophotometrically in a series of 19 solvents including water, alcohols and dipolar. aprotic media. Satisfactory correlations between the wave numbers of the long-wavelength band and solvent acceptor numbers are obtained in all media; only values, for carboxylic acids deviate from the regression line.
Spektrophotometrische Untersuchungen über die Solvatochromie der Komplexverbindung Fe(CN)2(phen)2
Zusammenfassung Das solvatochrome Verhalten vonbis-(Cyano)-bis-(9,10-phenanthrolin)-eisen(II) wurde in 19 Lösungsmitteln, darunter Wasser, Alkohole und dipolare aprotische Medien, spektrophotometrisch überprüft. In allen Medien wurden zufriedenstellende Korrelationen zwischen den Wellenzahlen der langwelligen Bande und den Akzeptorzahlen der Lösungsmittel erhalten; lediglich die Werte für Carbonsäuren weichen von der Ausgleichgeraden ab.相似文献
7.
Introduction Molecules containing different kinds of metal ions play an important role in molecular magnetism.1-3 So considerable attention has been paid to synthesizing heteronuclear complexes.1-4 As a potential bridging ligand, thiocyanate can coordinate to a harder metal center and softer ones with N and S atoms respectively. The complexes of thiocyanate and representative hard acidFe(III) ions usually have a six-coordinate octahe-dral structure such as [Fe(SCN)n]3-n and (Bu4N)4[Ag2-F… 相似文献
8.
Maria Zaharescu Maria Crisan A. Jitianu D. Crisan Aurelia Meghea Ileana Rau 《Journal of Sol-Gel Science and Technology》2000,19(1-3):631-635
Composite SiO2-iron oxide materials were prepared by three experimental procedures. In the first case (1), the iron oxides were precipitated during the sol-gel process. In the second case (2), the SiO2 matrix was initially obtained, and the iron oxides were formed by thermal treatment after impregnation of a soluble Fe2+ salt in the previously processed matrix. In the third method (3), ferrite powders, prepared by wet chemical method, were embedded into a SiO2 based sol-gel matrix. Two type of precursors (tetraethoxysilane (TEOS) or methyltriethoxysilane (MTEOS) were used as SiO2 sources. Various properties versus both type of precursor and on the method of preparation were noticed. Materials with high porosity and nano-sized iron oxide content could be prepared using the mentioned above methods. 相似文献
9.
A combination of simulated annealing with Langevin molecular dynamics and the basin-hopping with occasional jumping (BHOJ) technique was used to systematically determine the most stable configurations of self-interstitial atom (SIA) clusters I n (n = 1–38) in α-iron. In addition to the original BHOJ technique, we introduced an additional long jumping process in which a randomly selected less-bounded atom is moved to a neighbouring site of another SIA in the cluster to enhance the probability of locating the global minimum structure. With the obtained putative lowest energy structures, the binding energies as a function of cluster size were estimated. We also determined the sizes of particular stable clusters based on their geometrical symmetry. Furthermore, the values were extrapolated based on accurately determined formation energies, and are available for immediate use in kinetic Monte Carlo or rate theory models. 相似文献
10.
The kinetics of the bromate oxidation of tris(1,10-phenanthroline)iron(II) (Fe(phen)32+) and aquoiron(II) (Fe2+ (aq)) have been studied in aqueous sulfuric acid solutions at μ = 1.0M and with Fe(II) complexes in great excess. The rate laws for both reactions generally can be described as -d [Fe(II)]/6dt = d[Br?]/dt = k[Fe(II)] [BrO?3] for [H+]0 = 0.428–1.00M. For [BrO?3]0 = 1.00 × 10?4M. [Fe2+]0 = (0.724–1.45)x 10?2 M, and [H+]0 = 1.00M, k = 3.34 ± 0.37 M?1s?1 at 25°. For [BrO?3]0 = (1.00–1.50) × 10?4M, [Fe2+]0 = 7.24 × 10?3M ([phen]0 = 0.0353M), and [H+]0 = 1.00M, k = (4.40 ± 0.16) × 10?2 M?1s?1 at 25°. Kinetic results suggest that the BrO?3-Fe2+ reaction proceeds by an inner-sphere mechanism while the BrO?3-Fe(phen)32+ reaction by a dissociative mechanism. The implication of these results for the bromate-gallic acid and other bromate oscillators is also presented. 相似文献