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41.
Ohne Zusammenfassung 相似文献
42.
Ohne ZusammenfassungIV. Mittlg. Mh. Chem.68 (1936) 313, bzw. S.-B. Akad. Wiss. Wien (IIb)145 (1936) 533.Die ersten Versuche in dieser Richtung sind bereits in den Diss. von HerrnIsemann (Feb. 1936) und Frl.Singer (Juli 1936) angeführt. Auch K.Feist u. Mitarb. (Liebigs Ann. Chem.523 [1936] 289) haben sich bereits mit der Methylierung ihres Carboxy-iso-V-columbins, das mit unserem Isocolumbin identisch und auch richtigerweise so zu benennen ist, beschäftigt und dabei einen Methyläther der Formel C20H21O5· OCH3 erhalten, über den aber in der angeführten Arbeit keine weiteren Versuche mitgeteilt werden. 相似文献
43.
F. Wessely H. Hirschel G. Schlögl-Petziwal 《Monatshefte für Chemie / Chemical Monthly》1937,71(1):215-228
Ohne Zusammenfassung 相似文献
44.
F. Hecht H. Zellner A. A. Benedetti-Pichler A. Franke F. v. Wessely M. Nießner A. Grünwald G. Koller G. Ortner R. Dworzak E. Baroni 《Mikrochimica acta》1941,29(1-2):134-158
Ohne Zusammenfassung 相似文献
45.
Hammerath F Nishimoto S Grafe HJ Wolter AU Kataev V Ribeiro P Hess C Drechsler SL Büchner B 《Physical review letters》2011,107(1):017203
We report a comparative study of (63)Cu nuclear magnetic resonance spin lattice relaxation rates T(1)(-1) on undoped SrCuO(2) and Ca-doped Sr(0.9)Ca(0.1)CuO(2) spin chain compounds. A temperature independent T(1)(-1) is observed for SrCuO(2) as expected for an S=1/2 Heisenberg chain. Surprisingly, we observe an exponential decrease of T(1)(-1) for T<90 K in the Ca-doped sample evidencing the opening of a spin gap. The data analysis within the J(1)-J(2) Heisenberg model employing density-matrix renormalization group calculations suggests an impurity driven small alternation of the J(2)-exchange coupling as a possible cause of the spin gap. 相似文献
46.
Ko KT Kim K Kim SB Kim HD Kim JY Min BI Park JH Chang FH Lin HJ Tanaka A Cheong SW 《Physical review letters》2011,107(24):247201
We investigated the magnetic nature of Fe(1/4)TaS2 using x-ray absorption spectroscopy, photoemission spectroscopy, and first principles band calculations. The results show a large unquenched orbital magnetic moment (~1.0 μ(B)/Fe) at intercalated Fe sites, resulting in a gigantic magnetic anisotropy (H(A)?60 T). The magnetic coupling is well understood in terms of the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, suggesting a novel RKKY ferromagnet with Ising-type spin states. We also found that this indirect exchange coupling between the neighboring Fe spins is ferromagnetic and maximized at the Fe-Fe distance of 2×2 superstructure. 相似文献
47.
Flores-Camacho JM Fischer-Wolfarth JH Peter M Campbell CT Schauermann S Freund HJ 《Physical chemistry chemical physics : PCCP》2011,13(37):16800-16810
The heat of adsorption and sticking probability of CO on well-defined Pd nanoparticles were measured as a function of particle size using single crystal adsorption microcalorimetry. Pd particles of different average sizes ranging from 120 to 4900 atoms per particle (or from 1.8 to 8 nm) and Pd(111) were used that were supported on a model in situ grown Fe(3)O(4)/Pt(111) oxide film. To precisely quantify the adsorption energies, the reflectivities of the investigated model surfaces were measured as a function of the thickness of the Fe(3)O(4) oxide layer and the amount of deposited Pd. A substantial decrease of the binding energy of CO was found with decreasing particle size. Initial heat of adsorption obtained on the virtually adsorbate-free surface was observed to be reduced by about 20-40 kJ mol(-1) on the smallest 1.8 nm sized Pd particles as compared to the larger Pd clusters and the extended Pd(111) single crystal surface. This effect is discussed in terms of the size-dependent properties of the Pd nanoparticles. The CO adsorption kinetics indicates a strong enhancement of the adsorbate flux onto the metal particles due to a capture zone effect, which involves trapping of adsorbates on the support and diffusion to metal clusters. The CO adsorption rate was found to be enhanced by a factor of ~8 for the smallest 1.8 nm sized particles and by ~1.4 for the particles of 7-8 nm size. 相似文献
48.
Gertrude Adametz J. Swoboda F. Wessely 《Monatshefte für Chemie / Chemical Monthly》1962,93(6):1453-1456
Ohne Zusammenfassung 相似文献
49.
Ohne Zusammenfassung 相似文献
50.
Changes of the magnetic properties of ferromagnetic Co particles deposited on the radical31 x radical31R +/- 9 degrees reconstructed alpha-Al2O3(0001) as well as on a thin alumina film grown on a NiAl(110) substrate were investigated as a function of thermal annealing. On the thin film changes of the magnetic response were found above 500 K which correlates with changes in the particle size distribution. Annealing to 870 K leads to a permeation of the metal though the oxide film which causes significant changes in the ferromagnetic resonance response. On the alpha-Al2O3 single crystal sintering of particles requires temperatures above 600 K being about 100 K higher as compared to the thin alumina film. For large clusters intraparticle redistribution takes place already below 600 K a phenomenon not observed for the small clusters. In addition, a significant dependence of the measured g values from the substrate as well as the thermal treatment is found which can be understood in terms of the structural properties of the systems. 相似文献