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91.
R. J. Birgeneau R. W. Erwin P. M. Gehring M. A. Kastner B. Keimer M. Sato S. Shamoto G. Shirane J. Tranquada 《Zeitschrift für Physik B Condensed Matter》1992,87(1):15-19
The magnetic neutron scattering cross section in a crystal YBa2Cu3O6.5(T
c
=50 K) has been measured for energies between 4.5 meV and 15 meV and temperatures between 10 K and 275 K. From these data we extract the generalized susceptibility integrated around the (, ) position
These data are combined with those at 8.3 and 33.1 meV from a previous study. It is found thatI(, T) exhibits the simple temperature scaling form found previously in La2–x
Sr
x
CuO4. Specifically, in YBa2Cu3O6.5,I(, T)=I(, 0)2/tan–1 (/0.9T). Implications of this behavior for the d.c. and infrared conductivity are discussed. 相似文献
92.
93.
Frank Seela Matthias Zulauf Hans Reuter Guido Kastner 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(4):489-491
The isomorphous structures of the title molecules, 4‐amino‐1‐(2‐deoxy‐β‐d ‐erythro‐pentofuranosyl)‐3‐iodo‐1H‐pyrazolo‐[3,4‐d]pyrimidine, (I), C10H12IN5O3, and 4‐amino‐3‐bromo‐1‐(2‐deoxy‐β‐d ‐erythro‐pentofuranosyl)‐1H‐pyrazolo[3,4‐d]pyrimidine, (II), C10H12BrN5O3, have been determined. The sugar puckering of both compounds is C1′‐endo (1′E). The N‐glycosidic bond torsion angle χ1 is in the high‐anti range [?73.2 (4)° for (I) and ?74.1 (4)° for (II)] and the crystal structure is stabilized by hydrogen bonds. 相似文献
94.
Michael Kastner Michael Promberger Alfred Hüller 《Journal of statistical physics》2000,99(5-6):1251-1264
In the microcanonical ensemble, suitably defined observables show nonanalyticities and power-law behavior even for finite systems. For these observables, a microcanonical finite-size scaling theory is established and combined with the experimentally observed power-law behavior. Scaling laws are obtained which relate exponents of the finite system and critical exponents of the infinite system to the system-size dependence of the affiliated microcanonical observables. 相似文献
95.
Gottfried Mrkl Thomas Knott Peter Kreitmeier Thomas Burgemeister Fritz Kastner 《Helvetica chimica acta》2000,83(3):592-602
Diepoxy[18]annulenes(10.0): ( Z , E , Z , E , Z )‐Diepoxy[18]annulene(10.0) – a Highly Dynamic Annulene The McMurry reaction of (all‐E)‐5,5′‐([2,2′‐bifuran]‐5,5′‐diyl)bis[penta‐2,4‐dienal] ( 13 ) only occurs intramolecularly to give a mixture of the diepoxy[18]annulenes(10.0) 6 and 7 . Tetraepoxy[36]annulene(10.0.10.0) resulting from an intermolecular McMurry reaction is not formed. According to spectroscopic data, 6 is (Z,E,Z,E,Z)‐ and 7 (Z,E,E,Z,E)‐configured. The 1H‐NMR data confirm that in 6 the (E)‐ethene‐1,2‐diyl bonds (C(11)=C(12) and C(15)=C(16)) rotate around the adjacent σ‐bonds. Beginning at −70°, this rotation freezes, and 6 is becoming a diatropic aromatic ring system. Beside [18]annulene itself, (Z,E,Z,E,Z)‐diepoxy[18]annulene(10.0) 6 is the only hitherto known [18]annulene derivative with dynamic properties. 相似文献
96.
97.
I.?HahnEmail author M.?Kastner 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,50(1-2):311-314
A large deviation technique is used to calculate the microcanonical entropy function s(v,m) of the mean-field ϕ4-model as a function of the potential energy v and the magnetization m. As in the canonical ensemble, a continuous phase transition
is found. An analytical expression is obtained for the critical energy vc(J) as a function of the coupling parameter J. 相似文献
98.
Katharina Kastner Johannes Forster Hiromichi Ida Dr. Graham N. Newton Prof. Dr. Hiroki Oshio Prof. Dr. Carsten Streb 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(21):7686-7689
Controlling the assembly and functionalization of molecular metal oxides [MxOy]n? (M=Mo, W, V) allows the targeted design of functional molecular materials. While general methods exist that enable the predetermined functionalization of tungstates and molybdates, no such routes are available for molecular vanadium oxides. Controlled design of polyoxovanadates, however, would provide highly active materials for energy conversion, (photo‐) catalysis, molecular magnetism, and materials science. To this end, a new approach has been developed that allows the reactivity tuning of vanadium oxide clusters by selective metal functionalization. Organic, hydrogen‐bonding cations, for example, dimethylammonium are used as molecular placeholders to block metal binding sites within vanadate cluster shells. Stepwise replacement of the placeholder cations with reactive metal cations gives mono‐ and difunctionalized clusters. Initial reactivity studies illustrate the tunability of the magnetic, redox, and catalytic activity. 相似文献
99.
Motivated by recent experiments with two-component Bose–Einstein condensates, we study fully-connected spin models subject to an additional constraint. The constraint is responsible for the Hilbert space dimension to scale only linearly with the system size. We discuss the unconventional statistical physical and thermodynamic properties of such a system, in particular the absence of concentration of the underlying probability distributions. As a consequence, expectation values are less suitable to characterize such systems, and full distribution functions are required instead. Sharp signatures of phase transitions do not occur in such a setting, but transitions from singly peaked to doubly peaked distribution functions of an “order parameter” may be present. 相似文献
100.
Aluísio S. ReisJr Eliane S. C. Temba Geraldo F. Kastner Roberto P. G. Monteiro 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(2):567-572
Radiochemical separation of Pu, Am and U was tested from synthetic solutions and evaporator concentrate samples from nuclear
power plants for isolation of each of them for alpha-spectrometry analysis. The separation was performed by anion-exchange
chromatography, extraction chromatography, using TRU resin, and precipitation techniques. The aim of the study was to develop
a sensitive analytical procedure for the sequential determination of 242Pu, 238Pu, 239+240Pu, 241Am and 235, 238U in radioactive wastes. 238Pu, 242Pu, 243Am and 232U were used as tracers. The measurements of α emitting radionuclides were performed by semiconductor detector that is used
especially when spectrometric information is needed. For synthetic solutions the chemical recovery was based on associated
iron concentration and was about 93%. 相似文献