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11.
Shanghua Li Zeming He Muhammet S. Toprak Christian Stiewe Eckhard Müller Mamoun Muhammed 《固体物理学:研究快报》2007,1(6):259-261
Maize‐like CoSb3 powders were obtained via the chemical alloying method. After the consolidation of the nanopowder using hot press, the CoSb3 compact shows a higher Seebeck coefficient and lower thermal conductivity. For the investigated CoSb3, a ZT of 0.15 at 673 K is shown. Though the achieved ZT does not reach the optimal value (0.17 to 0.18) for pure CoSb3, due to its lower electrical conductivity, the novel structure fabrication provides an interesting and promising approach to enhancing the thermoelectric performance. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
12.
Muhammet Tamer Koşan 《Proceedings Mathematical Sciences》2009,119(4):453-458
Let R be a commutative Noetherian ring with non-zero identity and a be a maximal ideal of R. An R-module M is called minimax if there is a finitely generated submodule N of M such that M/N is Artinian. Over a Gorenstein local ring R of finite Krull dimension, we proved that the Socle of H
a
n
(R) is a minimax R-module for each n ≥ 0. 相似文献
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The reactions of hexachlorocyclotriphosphazene, N3P3Cl6, with N/O donor type N-alkyl or (aryl)-o-hydroxybenzylamines HO(C6H4)CH2NHR(Ar), [R(Ar) = C(CH3)3 (1), Ph (2)] produce monospirocyclic tetrachlorocyclotriphosphazenes (1a and 2a). The geminal substituted cyclotriphosphazenes (1b, 1d, 2b and 2d) are obtained from the reactions of 1 equiv. of 1a and 2a with 2 equiv. of pyrrolidine or morpholine in THF, while the fully substituted phosphazenes (1c, 1e, 2c and 2e) are formed from the reactions of 1a and 2a with the excess pyrrolidine or morpholine in toluene, between 24 and 48 h. The microwave-assisted reactions of 1a and 2a with excess pyrrolidine or morpholine in toluene afford the fully substituted products with higher yields than those which were obtained by conventional methods. The structural investigations of the compounds have been verified by elemental analyses, ESI-MS, FTIR, 1H, 13C, 31P NMR and HETCOR techniques. The crystal structure of 2a is determined by X-ray crystallography and the phosphazene ring is in the flattened boat form. Compounds 1b, 1d, 2b and 2d in which the spiro aryloxy moiety provides the one centre of chirality exist as racemates and the chirality has been confirmed by 31P NMR spectroscopy on addition of a chiral solvating agent (CSA), (S)-(+)-2,2,2-trifluoro-1-(9′-anthryl)ethanol. 相似文献
15.
Fei Ye Jian Qin Muhammet S. Toprak Mamoun Muhammed 《Journal of nanoparticle research》2011,13(11):6157-6167
Multifunctional core–shell composite nanoparticles (NPs) have been developed by the combination of three functionalities into
one entity, which is composed of a single Fe3O4 NP as the magnetic core, mesoporous silica (mSiO2) with cavities as the sandwiched layer, and thermosensitive poly(N-isopropylacrylamide-co-acrylamide) (P(NIPAAm-co-AAm)) copolymer as the outer shell. The mSiO2-coated Fe3O4 NPs (Fe3O4@mSiO2) are monodisperse and the particle sizes were varied from 25 to 95 nm by precisely controlling the thickness of mSiO2-coating layer. The P(NIPAAm-co-AAm) were then grown onto surface-initiator-modified Fe3O4@mSiO2 NPs through free radical polymerization. These core–shell composite NPs (designated as Fe3O4@mSiO2@P(NIPAAm-co-AAm)) were found to be superparamagnetic with high r
2 relaxivity. To manipulate the phase transition behavior of these thermosensitive polymer-coated NPs for future in vivo applications,
the characteristic lower critical solution temperature (LCST) was subtly tuned by adjusting the composition of the monomers
to be around the human body temperature (i.e. 37 °C), from ca. 34 to ca. 42 °C. The thermal response of the core–shell composite
NPs to the external magnetic field was also demonstrated. Owing to their multiple functionality characteristics, these porous
superparamagnetic and thermosensitive NPs may prove valuable for simultaneous magnetic resonance imaging (MRI), temperature-controlled
drug release, and temperature-programed magnetic targeting and separation applications. 相似文献
16.
Xiaodi Wang Ying Ma Abhilash Sugunan Jian Qin Muhammet S. Toprak Bin Zhu Mamoun Muhammed 《Journal of nanoparticle research》2011,13(11):5879-5885
A facile surfactant-free nonaqueous method is presented to prepare uniform quasi-octahedral ceria, CeO2, mesocrystals, in which only Ce(NO3)3 and octanol were used as the reactants at a reaction temperature of 150 °C. CeO2 sample synthesized using this technique consists of well-dispersed quasi-octahedrons and exhibits an uniform size and morphology.
Based on structural characterization, it is proposed that the CeO2 mesostructure was formed by self-assembly of primary nanocrystals based on unique 3D oriented-attachment mechanism. Optical
characterization exhibited a strong quantum confinement, revealing small size of primary nanocrystals. The thermal stability
and UV–Vis study reveal CeO2 mesocrystal has various potential for high temperature applications and optical apparatus applications. 相似文献
17.
We consider the initial value problem for the Klein‐Gordon equation in de Sitter spacetime. We use the central difference scheme on the temporal discretization. We also discretize the spatial variable using the finite element method with implicit and the Crank‐Nicolson schemes for the numerical solution of the initial value problem. In order to show the accuracy for the results of the solutions, we also examine the finite difference methods. We observe that the numerical results obtained by using these methods are compatible. 相似文献
18.
Highly diastereoselective polycyclization of homo(polyprenyl)arene analogues bearing terminal siloxyvinyl groups was catalyzed by tin(IV) chloride (10 mol %). The cyclizations of tert-butyldiphenylsilyl and triisopropylsilyl polyenol ethers gave 4alpha(equatorial)- and 4beta(axial)-siloxypolycycles as major isomers, respectively. The strong nucleophilicity of pro-C(9), a (6E) geometry, and a bulky silyl group effectively favored the alpha-preference, whereas the weak nucleophilicity of pro-C(9), a (6Z)-geometry, and less steric hindrance of a silyl group favored the beta-preference. [reaction: see text]. 相似文献
19.
Inverse stochastic resonance (ISR) is a recently pronounced phenomenon that is the minimum occurrence in mean firing rate of a rhythmically firing neuron as noise level varies. Here, by using a realistic modeling approach for the noise, we investigate the ISR with concrete biophysical mechanisms. It is shown that mean firing rate of a single neuron subjected to synaptic bombardment exhibits a minimum as the spike transmission probability varies. We also demonstrate that the occurrence of ISR strongly depends on the synaptic input regime, where it is most prominent in the balanced state of excitatory and inhibitory inputs. 相似文献
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