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911.
随着氧自由基(OFR)在疾病中的研究日趋深入,大量的资料证实氧自由基与充血性心力衰竭,动脉粥样硬化、心肌缺血、心律失常及淋巴细胞与心力衰竭的关系诸方面的发生,发匀有密切关系。 相似文献
912.
We study inverse semigroup amalgams [S
1,S
2;U], where S
1 and S
2 are finitely presented inverse semigroups with decidable word problem and U is an inverse semigroup with decidable membership problem in S
1 and S
2. We use a modified version of Bennett’s work on the structure of Schützenberger graphs of the ℛ-classes of S
1*
U
S
2 to state sufficient conditions for the amalgamated free products S
1*
U
S
2 having decidable word problem. 相似文献
913.
Gerald S. Berke Dennis M. Moore Peter A. Monkewitz David G. Hanson Bruce R. Gerratt 《Journal of voice》1989,3(4):306-313
The particle velocity across the glottis was measured with simultaneous electroglottography, photoglottography, and subglottic pressure in an in vivo canine model of phonation. A constant temperature anemometer measured flow velocity at five midline anterior to posterior glottal positions. Tracheal input air flow was varied in five steps from 175 to 500 cc/s, while vocal fold approximation was achieved by constant electrical stimulation of the laryngeal nerves. For all levels of air flow, a decreasing peak velocity gradient was observed from the anterior commissure to the arytenoids. Time-varying features of the flow velocity are discussed in relation to glottal vibratory events and aerodynamics. 相似文献
914.
Sébastien Falguières 《Journal of Functional Analysis》2008,254(9):2317-2328
We show that any compact group can be realized as the outer automorphism group of a factor of type II1. This has been proved in the abelian case by Ioana, Peterson and Popa [A. Ioana, J. Peterson, S. Popa, Amalgamated free products of w-rigid factors and calculation of their symmetry group, math.OA/0505589, Acta Math., in press] applying Popa's deformation/rigidity techniques to amalgamated free product von Neumann algebras. Our methods are a generalization of theirs. 相似文献
915.
An organocatalysed protocol for one-pot synthesis of 1,4-dihydropyridines via three-component coupling of cinnamaldehyde, aniline and β-keto esters under solvent free conditions at ambient temperature is reported. The reaction is generally very fast and the products are obtained in high yield. The catalytic activity of small organic molecules like amino acids (acidic, basic and neutral), ephedrine and cinchona alkaloids was studied. 相似文献
916.
917.
Xiao‐Lin Wang Yan‐Dong He Li‐Yan You Zhong‐Yuan Lu Ze‐Sheng Li 《Journal of Polymer Science.Polymer Physics》2009,47(4):353-365
Dissipative particle dynamics simulations are applied to investigate the monolayer and multilayer film formations on different solid substrates by physical deposition. The influences of the polymer concentration, the polymer chain length, the solvent quality, and the interactions between the polymer solution and the solid substrate surface on the film formation dynamics and the mechanism are studied in detail. The results are analyzed in terms of the thickness and the shape of the deposited film, the kinetics of phase separation in the polymer solution, and the contact angle formed between the polymer aggregations and the substrate surface. Moreover, we suggest two strategies, designing a deposition process analogous to “chemical titration” and physically blocking interlayer diffusion by a simple crosslinked network barrier, to deposit the compact monolayer and multilayer films with better quality, respectively. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 353–365, 2009 相似文献
918.
Band structure parameters such as the conduction band edge, the valence band edge and the quasi‐particle gap of diffusing CdSe quantum dots (Q‐dots) of various sizes were determined using cyclic voltammetry. These parameters are strongly dependent on the size of the Q‐dots. The results obtained from voltammetric measurements are compared to spectroscopic and theoretical data. The fit obtained to the reported calculations based on the semi‐empirical pseudopotential method (SEPM)—especially in the strong size‐confinement region, is the best reported so far, according to our knowledge. For the smallest CdSe Q‐dots, the difference between the quasi‐particle gap and the optical band gap gives the electron–hole Coulombic interaction energy (Je1,h1). Interband states seen in the photoluminescence spectra were verified with cyclic voltammetry measurements. 相似文献
919.
L.R.S. Araújo F.C. Montenegro D.R. Cornejo 《Journal of magnetism and magnetic materials》2008,320(14):e343-e346
The hysteretic behavior of mechanically alloyed nanocomposites FeCo+MnO was studied at high temperatures. These composites present an unusual high and thermally stable coercivity, compared to FeCo milled at equal conditions. Coercivity enhancement was observed in hysteresis loops obtained between room temperature and 750 K. It is attributed to the isolation of the FeCo ferromagnetic particles by the paramagnetic MnO (TN=120 K). The Mrev(Mirr)H curves are clearly linear for the composite, indicating that coherent rotation is the reversal mechanism in these materials. 相似文献
920.
Nina Perkas Michael Shuster Galina Amirian Yuri Koltypin Aharon Gedanken 《Journal of polymer science. Part A, Polymer chemistry》2008,46(5):1719-1729
Silver nanoparticles were immobilized on the surface of polypropylene (PP) porous beads by an ultrasound‐assisted reduction method. The structure and properties of the silver–PP composite were characterized with XRD, TEM, HRSEM, EDX, XPS, and Raman spectroscopy. Water‐soluble polymers such as PEG, PVA, and PVP were used as stabilizing agents for preventing the agglomeration of the silver nanoparticles. With PVP, a homogeneous distribution of silver nanocrystals, 50 nm in size, on the PP surface was achieved. The mechanism proposed for the silver anchoring to the inert polymer accounts for a localized melting of the PP. The beads of the silver PP composite demonstrated good stability and high antibacterial activity. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1719–1729, 2008 相似文献