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851.
Marius Crainic 《Commentarii Mathematici Helvetici》2003,78(4):681-721
In the first section we discuss Morita invariance of
differentiable/algebroid cohomology.In the second section we extend the Van Est isomorphism to
groupoids. As a first application we clarify the connection
between differentiable and algebroid cohomology (proved in
degree 1, and conjectured in degree 2 by Weinstein-Xu
[50]). As a second application we extend Van Ests
argument for the integrability of Lie algebras. Applied to
Poisson manifolds, this immediately implies the integrability
criterion of Hector-Dazord [14].In the third section we describe the relevant characteristic classes of
representations, living in algebroid cohomology, as well as
their relation to the Van Est map. This extends
Evens-Lu-Weinsteins characteristic class $\theta_{L}$
[20] (hence, in particular, the modular class of Poisson
manifolds), and also the classical characteristic classes of
flat vector bundles [2, 30].In the last section we
describe applications to Poisson geometry. 相似文献
852.
We study the local operator space structure of nuclear C
*
-algebras. It is shown that a C
*
-algebra is nuclear if and only if it is an 𝒪ℒ∞,λ space for some (and actually for every) λ>6. The 𝒪ℒ∞ constant λ provides an interesting invariant
for nuclear C
*
-algebras. Indeed, if 𝒜 is a nuclear C
*
-algebra, then we have 1≤𝒪ℒ∞(𝒜)≤6, and if 𝒜 is a unital nuclear C
*
-algebra with , we show that 𝒜 must be stably finite. We also investigate the connection between the rigid 𝒪ℒ∞,1+ structure and the rigid complete order 𝒪ℒ∞,1+ structure on C
*
-algebras, where the latter structure has been studied by Blackadar and Kirchberg in their characterization of strong NF C
*
-algebras. Another main result of this paper is to show that these two local structrues are actually equivalent on unital
nuclear C
*
-algebras. We obtain this by showing that if a unital (nuclear) C
*
-algebra is a rigid 𝒪ℒ∞,1+ space, then it is inner quasi-diagonal, and thus is a strong NF algebra. It is also shown that if a unital (nuclear) C
*
-algebra is an 𝒪ℒ∞,1+ space, then it is quasi-diagonal, and thus is an NF algebra.
Received: 26 June 2001 / Revised version: 7 May 2002 / Published online: 10 February 2003
Mathematics Subject Classification (2000): 46L07, 46L05, 47L25
Junge and Ruan were partially supported by the National Science Foundation. Ozawa was supported by the Japanese Society for
Promotion of Science. 相似文献
853.
Cyclodipeptides containing L -Thr and L -His residues have been studied by 1H NMR in D2O and DMSO-d6. In the neutral form in D2O as in DMSO-d6, the folded form of the L -His residue is not unique. The diketopiperazine ring seems to be not strictly planar. 相似文献
854.
Sans résumé 相似文献
855.
Michelle Beniere Marius Chemla François Beniere 《Journal of Physics and Chemistry of Solids》1976,37(5):525-538
We compare the self-diffusion coefficients, respectively determined with radioactive tracers and from the ionic conductivity, in the intrinsic range of pure KCl and NaCl single crystals. The correlation effect and the vacancy pair effect originate deviations between both values. The vacancy pair effect is successfully measured by studying the influence of divalent anions and divalent cations on the self-diffusion coefficients in KCl. We derive the value of the correlation factor f = 0.75 ±0.04, which provides a direct experimental verification of the correlation theory (f = 0.78). The whole set of the recent measurements of transport processes and isotope effects in NaCl are reexamined by considering this value for the correlation factor. We derive the whole set of properties of the free and associated vacancies in NaCl and KCl. 相似文献
856.
Marius Dadarlat 《K-Theory》1995,9(2):117-137
It is shown that two unital *-homomorphisms from a commutativeC*-algebraC(X) to a unitalC*-algebraB are stably approximately unitarily equivalent if and only if they have the same class in the quotient of the Kasparov groupKK(C(X),B) by the closure of zero. A suitable generalization of this result is used to prove a classification result for certain inductive limitC*-algebrasThis research was partially supported by NSF grant DMS-9303361 相似文献
857.
C.E.A. Grigorescu E. Valerio L. Tortet G. Pavelescu C. Ducu H.J. Trodahl N. Strickland W.R. Branford 《Applied Surface Science》2007,253(19):8102-8106
Thin films of nonstoichiometric Heusler alloys Co2MnSbxSn1−x (x = 0.2; 0.4; 0.6; 0.8) have been grown by pulsed laser deposition (double-target/double beam configuration) on Si (1 0 0) substrates using a KrF excimer laser (λ = 248 nm, τ = 20 ns). The substrate temperature was held at 300 K in all experiments to prevent interface interdiffusion of the species. A comparison between the compositions of films and corresponding targets has been done through energy dispersive X-ray spectroscopy (EDS) analysis showing a very satisfactory match. Scanning electron microscopy (SEM) imaging served to investigate the morphology of the films in order to determine the size and density of droplets which may influence the optical data. Optical conductivity derived from reflectivity measurements shows absorption onsets close to 1 eV, which corresponds to the onset of valence-to-conduction transitions in the minority spin bands theoretically predicted. The values of the saturation magnetisation measured at 300 K on the quaternary alloys are very close to those of ternary ones for which either half-metallic properties or high spin polarisation were theoretically predicted. 相似文献
858.
859.
A two-dimensional TROSY-based z-exchange 1H-15N correlation experiment for the quantitative analysis of kinetic processes in the slow exchange regime is presented. The pulse scheme converts the product operator terms Nz into 2NzHz and 2NzHz into -Nz in the middle of the z-mixing period, thereby suppressing the buildup of spurious semi-TROSY peaks arising from the different relaxation rates for the Nz and 2NzHz terms and simplifying the behavior of longitudinal magnetization for an exchanging system during the mixing period. Theoretical considerations and experimental data demonstrate that the TROSY-based z-exchange experiment permits quantitative determination of rate constants using the same procedure as that for the conventional non-TROSY 15Nz-exchange experiment. Line narrowing as a consequence of the use of the TROSY principle makes the method particularly suitable for kinetic studies at low temperature, thereby permitting activation energies to be extracted from data acquired over a wider temperature range. We applied this method to the investigation of the process whereby the HoxD9 homeodomain translocates between specific target sites on different DNA molecules via a direct transfer mechanism without going through the intermediary of free protein. The activation enthalpy for intermolecular translocation was determined to be 17 kcal/mol. 相似文献
860.
The novel dimethyltin-containing polyanion [{(CH3)2Sn}6(OH)2O2(H2BW13O46)2]12- (1) is composed of two [H2BW13O46]9- clusters linked by an unprecedented planar, hexameric [{(CH3)2Sn}6(OH)2O2]8+ organostannoxane moiety, representing the first X-ray structural characterization of a molecular hybrid organic-inorganic tungstoborate and of the elusive [HnBW13O46](11-n)- species. 相似文献