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951.
Ramón?Flores Jér?me?SchererEmail authorView authors OrcID profile 《Mediterranean Journal of Mathematics》2018,15(6):229
We prove that, in the category of groups, the composition of a cellularization and a localization functor need not be idempotent. This provides a negative answer to a question of Emmanuel Dror Farjoun. 相似文献
952.
953.
Allen C;Competency & Credentialing Institute 《OR manager》2010,26(9):26, 28, 30
954.
Saver C 《OR manager》2010,26(9):1, 7-1,11
955.
Cynthia Will 《Monatshefte für Mathematik》2010,159(4):425-437
The only known examples of non-compact Einstein homogeneous spaces are standard solvmanifolds (special solvable Lie groups endowed with a left invariant metric), and according to a long standing conjecture, they might be all. The classification of Einstein solvmanifolds is equivalent to the one of Einstein nilradicals, i.e. nilpotent Lie algebras which are nilradicals of the Lie algebras of Einstein solvmanifolds. Up to now, very few examples of ${\mathbb N}$ -graded nilpotent Lie algebras that cannot be Einstein nilradicals have been found. In particular, in each dimension, there are only finitely many known. We exhibit in the present paper two curves of pairwise non-isomorphic nine-dimensional two-step nilpotent Lie algebras which are not Einstein nilradicals. 相似文献
956.
Getúlio de S. Rosa Bernardo A. Souto Cynthia N. Pereira Bruna C. Teixeira Maurício S. dos Santos 《Journal of heterocyclic chemistry》2019,56(6):1825-1830
A series of 28 hybrids pyrazole‐imidazolines 1a – n and 2a – n were synthesized by a new methodology using microwave irradiation, in short time (20–30 min), in low power (50–70 W), and in 34–92% yield. Among all methodologies evaluated, no side products were obtained. All derivatives were completely characterized by FT–IR, 1H and 13C NMR, GC–MS, and HRMS. 相似文献
957.
Auditory filter shape and frequency tuning may be derived by measuring changes in pure tone thresholds as a function of the bandwidth of notched-noise maskers. When these psychophysical methods were applied to CBA/CaJ mice, the resulting filter shapes were well fit by roex(p,r) functions originally developed for human subjects. The equivalent rectangular bandwidths (ERBs) of the filter shapes ranged from 16 to 19% of test frequencies between 8 to 16 kHz. These ERBs correspond well to the performance of humans at high frequencies and the limited number of mammalian species that have been characterized with notched-noise procedures. Frequency tuning was maintained throughout most of the adult lifespan and then showed a selective high-frequency loss at ages beyond 2 years. These results suggest that auditory filtering effects in adult CBA/CaJ mice are similar to normal processes in other mammalian species and provide an excellent model of human presbycusis when they begin to degrade in aging individuals. 相似文献
958.
Alexander Mondragn‐Díaz Elvis Robles‐Marín Brenda A. Murueta‐Cruz Juan C. Aquite Paulina R. Martínez‐Alanis Marcos Flores‐Alamo Gabriel Aulln Luis Norberto Benítez Ivan Castillo 《化学:亚洲杂志》2019,14(19):3301-3312
Two nickel complexes supported by tridentate NS2 ligands, [Ni2(κ‐N,S,S,S′‐NPh{CH2(MeC6H2R′)S}2)2] ( 1 ; R′=3,5‐(CF3)2C6H3) and [Ni2(κ‐N,S,S,S′‐NiBu{CH2C6H4S}2)2] ( 2 ), were prepared as bioinspired models of the active site of [NiFe] hydrogenases. The solid‐state structure of 1 reveals that the [Ni2(μ‐ArS)2] core is bent, with the planes of the nickel centers at a hinge angle of 81.3(5)°, whereas 2 shows a coplanar arrangement between both nickel(II) ions in the dimeric structure. Complex 1 electrocatalyzes proton reduction from CF3COOH at ?1.93 (overpotential of 1.04 V, with icat/ip≈21.8) and ?1.47 V (overpotential of 580 mV, with icat/ip≈5.9) versus the ferrocene/ferrocenium redox couple. The electrochemical behavior of 1 relative to that of 2 may be related to the bent [Ni2(μ‐ArS)2] core, which allows proximity of the two Ni???Ni centers at 2.730(8) Å; thus possibly favoring H+ reduction. In contrast, the planar [Ni2(μ‐ArS)2] core of 2 results in a Ni???Ni distance of 3.364(4) Å and is unstable in the presence of acid. 相似文献
959.
M. Pieruccini A. Flores U. Nöchel G. Di Marco N. Stribeck F. J. Baltá Calleja 《The European physical journal. E, Soft matter》2008,27(4):365-373
The process of re-crystallization in poly(ethylene terephthalate) is studied by means of X-ray diffraction (SAXS and WAXS)
and dynamical mechanical thermal analysis. Samples cold-crystallized for 9h at the temperatures T
c = 100 fcir#circ;C and T
c = 160 fcir#circ;C, i.e. in the middle of the relaxation region and close to its upper bound, respectively, are analyzed. During heating from room temperature, a structural
rearrangement of the stacks is always found at T
r ≃ T
c + 20 fcir#circ;C. This process is characterized by a decrease of the linear crystallinity, irrespective of Tc; on the other hand, the WAXS crystallinity never increases with T below Tc+30fcir#circ;C. The lamellar thickness in the low-Tc sample decreases significantly after the structural transition, whereas in the high-Tc sample the lamellar thickness remains almost unchanged. In both, high- and low-Tc, the interlamellar thickness increases above Tr. Moreover, the high-Tc sample shows a lower rate of decrease of the mechanical performance with increasing T as the threshold Tr is crossed. This result is interpreted in terms of the formation of rigid amorphous domains where the chains are partially
oriented. The presence of these domains would determine i) the stabilization of the crystalline lamellae from the thermodynamic
point of view and ii) the increase of the elastic modulus of the amorphous interlamellar regions. This idea is discussed by
resorting to a phase diagram. An estimation of the chemical-potential increase of the interlamellar amorphous regions, due
to the enhancement of the structural constraints hindering segmental mobility, is offered. Finally, previous calculations
developed within the framework of the Gaussian chain model (F.J. Baltá Calleja et al., Phys. Rev. B 75, 224201 (2007)) are used here to estimate the degree of chain orientation induced by the structural transition of the stacks. 相似文献
960.
This paper is devoted to the study of the hydrodynamic stage of a two-component dense fluid. Starting from the BBGKY hierarchy obtained earlier, we first derive the expressions for the generalized fluxes. We proceed to set up the generalized kinetic equations, using Bogoliubov's functional assumption. Then we solve these equations by means of a Chapman-Enskog method. The generalized expressions for the transport coefficients are thus obtained. All our results are independent of the existence of density expansions of the relevant quantities. 相似文献