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21.
LetA be the transformation groupC
*-algebra associated with an arbitrary orientation-preserving homeomorphism of . ThisC
*-algebra contains an infinite family of projections, called Rieffel projections, each of which generates theK
0-groupK
0(A). Although these projections must beK-theoretically equivalent, it is easy to see that most are not Murray-von Neumann equivalent. The mystery of how large the matrix algebra must be to implement theK-theory equivalence, is solved by explicitly constructing the equivalence in the smallest possible algebra:A with unit adjoined.Partially supported by NSF Grant DMS 8901923. 相似文献
22.
Ando N. Tasaki S. Hato Y. Marumo C. Natsume Y. Ohmori S. Ito A. Tanaka K. 《Journal of Thermal Analysis and Calorimetry》2002,70(2):301-308
The polyacenic semiconductive (PAS) material is a typical amorphous carbon prepared by pyrolysis of phenolformaldehyde resin,
and is actually utilized as anode of high-capacity rechargeable batteries. In this work, change in the discharging amount
of Li+ before and after heat-treatment of the PAS electrodes at the various doping level was examined in detail. As a result, the
doped Li can be classified into two types: (i) heat-resistant Li-dopant (or Li-dopant with high diffusion coefficient) and
(ii)heat-fragile Li-dopant (or Li-dopant with low diffusion coefficient). The latter Li-dopants are generated above the doping
level of 30% ([Li]/[C]→0.3) and is considered to be the origin of high-capacity of PAS anode compared with that of graphite
anode. This aspect is also supported by the ESR, 7Li-NMR, and XPS observation results.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
23.
24.
Muon spin relaxation (SR) studies were carried out on YFeMnO4. Two interesting phenomena were found in measurements of longitudinal relaxation time spectra atT>T
cusp for a single crystal: (1) difference of the relaxation rates between the directions parallel with and perpendicular to thec-axis, and (2) suppression of local field fluctuations in a longitudinal external field. The spectra atT >T
cusp were reproduced with the function exp[-(0
t)]. The results are discussed under a picture of the magnetic spin fluctuations of triangular antiferromagnets. 相似文献
25.
Zbynek Prokop Dr. Yukari Sato Dr. Jan Brezovsky Tomas Mozga Radka Chaloupkova Dr. Tana Koudelakova Petr Jerabek Veronika Stepankova Ryo Natsume Dr. Jan G. E. van Leeuwen Dick B. Janssen Prof. Jan Florian Dr. Yuji Nagata Dr. Toshiya Senda Dr. Jiri Damborsky Prof. 《Angewandte Chemie (International ed. in English)》2010,49(35):6111-6115
26.
Full details for the total synthesis of (±)-nominine, a hetisine-type aconite alkaloid, are presented in three parts. Here (part 1), we describe the preparation of the key tetracyclic intermediate 6. Our palladium-catalyzed intramolecular α-arylation was adopted for preparation of the intermediate 4 with an angular formyl group. An acetal-ene reaction was then employed for C14-C20 bond formation to secure 6 from 5. The reaction mechanism of the acetal-ene reaction is discussed, and a method for removal of the 2-hydroxyethyl group from 6 is developed. 相似文献
27.
We discuss a topological method to quantize closed surfaces. 相似文献
28.
Intramolecular arylation of properly designed substrates bearing a ketone, formyl, or nitro terminating group was achieved by use of a PdCl2(Ph3P)2-Cs2CO3 reaction system to form a variety of carbocyclic compounds. Arylation in ketone compounds afforded benzene-annulated bridged or spirocycloalkanone derivatives, depending on the structure of the cyclization precursors. Arylation in formyl compounds occurred at the α-position (α-arylation) or at the carbonyl carbon (carbonyl-arylation) depending on the structure of the cyclization precursors and on the reaction solvent. An α-arylated secondary nitro group was partially transformed to ketone in the manner of the Nef reaction, whereas a tertiary nitro group was partially eliminated to afford a styrene-type olefin. 相似文献
29.
We introduce the notion of a strict quantization of a symplectic manifold and show its existence under a topological condition. 相似文献
30.
Tomotaka Natsume 《Journal of Dispersion Science and Technology》2013,34(11):1557-1562
The 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) liposome has been characterized in its stability and membrane permeability to 5(6)-carboxyfluorescein (CF) in the shear flow generated in the cone-and-plate geometry. The CF-containing liposomes (CFLs) were 101–323 nm in the mean diameter D P as measured with the dynamic light scattering (DLS) method. Adsorption of lipids to the cone-and-plate was observed, which clearly depended on the shear stress applied at the shear rate γ up to 1.5 × 103 s?1. The permeability of CFLs with D P of 101 and 117 nm definitely increased at the maximum γ value where the adsorption was negligible. The permeability coefficient of CF at 40°C in the shear flow was 5.7 times larger than that in the static liquid system. The DLS measurements revealed that the size distribution of CFLs with D P of 101–189 nm was practically unchanged under the shear stress even at 55°C. The results obtained show that the shear stress can permeabilize the CFL membranes with neither structural collapse nor coalescence. 相似文献