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81.
We introduce noncommutative JB*-algebras which generalize both B*-algebras and JB*-algebras and set up the bases for a representation theory of noncommutative JB*-algebras. To this end we define noncommutative JB*-factors and study the factor representations of a noncommutative JB*-algebra. The particular case of alternative B*-factors is discussed in detail and a Gelfand-Naimark theorem for alternative B*-algebras is given. 相似文献
82.
In this paper we continue to study the spectral norms and their completions ([4]) in the case of the algebraic closure $ \overline {\mathbb Q} $ of ? in ?. Let $ \widetilde{\overline{\mathbb{Q}}} $ be the completion of $ \overline {\mathbb Q} $ relative to the spectral norm. We prove that $ \widetilde{\overline{\mathbb{Q}}} $ can be identified with the R‐subalgebra of all symmetric functions of C(G), where C(G) denotes the ?‐Banach algebra of all continuous functions defined on the absolute Galois group G = Gal$ {\overline {\mathbb Q}} / {\mathbb Q} $. We prove that any compact, closed to conjugation subset of ? is the pseudo‐orbit of a suitable element of $ \widetilde{\overline{\mathbb{Q}}} $. We also prove that the topological closure of any algebraic number field in $ \widetilde{\overline{\mathbb{Q}}} $ is of the form $\widetilde{\mathbb{Q}[x]}$ with x in $ \widetilde{\overline{\mathbb{Q}}} $. 相似文献
83.
Gas‐phase elimination kinetics of selected aliphatic α,β‐unsaturated aldehydes catalyzed by hydrogen chloride 下载免费PDF全文
Libia L. Julio José R. Mora Alexis Maldonado Gabriel Chuchani 《Journal of Physical Organic Chemistry》2015,28(4):261-265
The gas‐phase elimination of 2‐methyl‐2‐propenal catalyzed by HCl yields propene and CO gas, while E‐2‐pentenal with the same catalyst gives butene and CO gas. The kinetics determinations were carried out in a static system with the reaction vessels deactivated with allyl bromide and the presence of the free radical inhibitor toluene. Temperature and pressure ranges were 350.0–410.0 °C and 34–76 Torr. The elimination reactions are homogeneous and unimolecular, and follow a first‐order rate law. The rate coefficients for the reactions are expressible by the following Arrhenius equations: Data from the kinetic and thermodynamic parameters of these catalyzed elimination reactions implies a mechanism of a concerted five‐membered cyclic transition state structure for the formation of the corresponding olefin and carbon monoxide. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
84.
R.?CombescotEmail author C.?Mora 《The European Physical Journal B - Condensed Matter and Complex Systems》2005,44(2):189-202
We explore the nature of the transition to the Fulde-Ferrell-Larkin-
Ovchinnikov superfluid phases
in the low temperature range in two dimensions, for the simplest
isotropic BCS model. This is done by applying the Larkin-Ovchinnikov
approach to this second order transition. We show that there is a
succession of transitions toward ever more complex order parameters
when the temperature goes to zero. This gives rise to a cascade with, in
principle, an infinite number of transitions. Except for one case, the
order parameter at the transition is a real superposition of cosines with
equal weights. The directions of these wavevectors are equally spaced
angularly, with a spacing which goes to zero when the temperature goes
to zero. This singular behaviour in this T = 0 limit is deeply linked to
the two-dimensional nature of the problem. 相似文献
85.
This paper shows, by means of Kronecker’s theorem, the existence of infinitely many privileged regions called $r$ -rectangles (rectangles with two semicircles of small radius $r$ ) in the critical strip of each function $L_{n}(z)\!:=\!$ $1-\sum _{k=2}^{n}k^{z}$ , $n\!\ge \!2$ , containing exactly $\left[ \dfrac{T\log n}{2\pi }\right] +1$ zeros of $L_{n}(z)$ , where $T$ is the height of the $r$ -rectangle and $\left[\cdot \right]$ represents the integer part. 相似文献
86.
Paul Gundel Gema Martinez‐Criado Martin C. Schubert Juan Angel Sans Wolfram Kwapil Wilhelm Warta Eicke R. Weber 《固体物理学:研究快报》2009,3(9):275-277
Synchrotron based X‐ray excited optical luminescence (XEOL) has been measured with many direct bandgap semiconductors. We present XEOL measurements on crystalline silicon (Si), obtained despite of its indirect bandgap and the consequently low luminescence efficiency. Spectra of monocrystalline and multicrystalline (mc) Si at room temperature are compared to theoretical spectra. A possible application in the synchrotron‐based research on mc‐Si is exemplified by combining XEOL, X‐ray fluorescence (XRF) spectroscopy, photoluminescence (PL) spectroscopy, and microscope images of grain boundaries. This approach can be utilized to investigate the recombination activity of metal precipitates, to analyze areas of different lifetimes on mc‐Si samples and to correlate additional material parameters to XRF measurements. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
87.
We study the geometry and dynamics of discrete subgroups $\Gamma $ of $\mathrm{PSL}(3,\mathbb C )$ with an open invariant set $\Omega \subset \mathbb P _\mathbb{C }^2$ where the action is properly discontinuous and the quotient $\Omega /\Gamma $ contains a connected component whicis compact. We call such groups quasi-cocompact. In this case $\Omega /\Gamma $ is a compact complex projective orbifold and $\Omega $ is a divisible set. Our first theorem refines classical work by Kobayashi–Ochiai and others about complex surfaces with a projective structure: We prove that every such group is either virtually affine or complex hyperbolic. We then classify the divisible sets that appear in this way, the corresponding quasi-cocompact groups and the orbifolds $\Omega /\Gamma $ . We also prove that excluding a few exceptional cases, the Kulkarni region of discontinuity coincides with the equicontinuity region and is the largest open invariant set where the action is properly discontinuous. 相似文献
88.
Roser Pons Cristina Ibez Ana B. Buades Antonio Franconetti Angel Garcia‐Raso Juan J. Fiol Angel Terrn Elies Molins Antonio Frontera 《应用有机金属化学》2019,33(6)
We report the synthesis and X‐ray characterization of the N6‐benzyl‐N6‐methyladenine ligand (L) and three metal complexes, namely [Zn(HL)Cl3]·H2O ( 1 ), [Cd(HL)2Cl4] ( 2 ) and [H2L]2[Cd3(μ‐L)2(μ‐Cl)4Cl6]·3H2O ( 3 ). Complex 1 consists of the 7H‐adenine tautomer protonated at N3 and coordinated to a tetrahedral Zn(II) metal centre through N9. The octahedral Cd(II) in complex 2 is N9‐coordinated to two N6‐benzyl‐N6‐methyladeninium ligands (7H‐tautomer protonated at N3) that occupy apical positions and four chlorido ligands form the basal plane. Compound 3 corresponds to a trinuclear Cd(II) complex, where the central Cd atom is six‐coordinated to two bridging μ‐L and four bridging μ‐Cl ligands. The other two Cd atoms are six‐coordinated to three terminal chlorido ligands, to two bridging μ‐Cl ligands and to the bridging μ‐L through N3. Essentially, the coordination patterns, degree of protonation and tautomeric forms of the nucleobase dominate the solid‐state architectures of 1 – 3 . Additionally, the hydrogen‐bonding interactions produced by the endocyclic N atoms and NH groups stabilize high‐dimensional‐order supramolecular assemblies. Moreover, energetically strong anion–π and lone pair (lp)–π interactions are important in constructing the final solid‐state architectures in 1 – 3 . We have studied the non‐covalent interactions energetically using density functional theory calculations and rationalized the interactions using molecular electrostatic potential surfaces and Bader's theory of atoms in molecules. We have particularly analysed cooperative lp–π and anion–π interactions in 1 and π+–π+ interactions in 3 . 相似文献
89.
Karen Rodríguez-Villar Lilin Ypez-Mulia Miguel Corts-Gines Jacobo David Aguilera-Perdomo Edgar A. Quintana-Salazar Kevin Samael Olascoaga Del Angel Francisco Corts-Benítez Juan Francisco Palacios-Espinosa Olivia Soria-Arteche Jaime Prez-Villanueva 《Molecules (Basel, Switzerland)》2021,26(8)
Indazole is an important scaffold in medicinal chemistry. At present, the progress on synthetic methodologies has allowed the preparation of several new indazole derivatives with interesting pharmacological properties. Particularly, the antiprotozoal activity of indazole derivatives have been recently reported. Herein, a series of 22 indazole derivatives was synthesized and studied as antiprotozoals. The 2-phenyl-2H-indazole scaffold was accessed by a one-pot procedure, which includes a combination of ultrasound synthesis under neat conditions as well as Cadogan’s cyclization. Moreover, some compounds were derivatized to have an appropriate set to provide structure-activity relationships (SAR) information. Whereas the antiprotozoal activity of six of these compounds against E. histolytica, G. intestinalis, and T. vaginalis had been previously reported, the activity of the additional 16 compounds was evaluated against these same protozoa. The biological assays revealed structural features that favor the antiprotozoal activity against the three protozoans tested, e.g., electron withdrawing groups at the 2-phenyl ring. It is important to mention that the indazole derivatives possess strong antiprotozoal activity and are also characterized by a continuous SAR. 相似文献
90.
Generator‐collector Voltammetry at Dual‐plate Gold‐gold Microtrench Electrodes as Diagnostic Tool in Ionic Liquids 下载免费PDF全文
Miguel Angel Montiel Jesus Iniesta Andrew J. Gross Thies Thiemann Frank Marken 《Electroanalysis》2016,28(5):1068-1076
Ionic liquids provide high viscosity solvent environments with interesting voltammetric characteristics and new electrochemical mechanisms. Here, a gold‐gold dual‐plate microtrench electrode is employed in generator‐collector mode to enhance viscosity‐limited currents in ionic liquids due to fast feedback within small inter‐electrode gaps (5 μm inter‐electrode gap, 27 μm microtrench depth) and to provide a mechanistic diagnosis tool. Three redox systems in the ionic liquid BMIm+BF4? are investigated: (i) ferrocene oxidation, (ii) oxygen reduction, and (iii) 2‐phenyl‐naphthyl‐1,4‐dione reduction. Both transient and steady state voltammetric responses are compared. Asymmetric diffusion processes, reaction intermediates, and solubility changes in the ionic liquid are revealed. 相似文献