排序方式: 共有71条查询结果,搜索用时 93 毫秒
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Minsu Seol Heejin Kim Wooseok Kim Kijung Yong 《Electrochemistry communications》2010,12(10):1416-1418
Highly efficient photoelectrochemical (PEC) hydrogen generation was achieved by fabricating CdSe deposited ZnO/CdS core/shell nanowire (NW) array photoanodes by a facile three-step solution-based method. Well-defined electrical pathways in 1-dimensional (1D) NW structures allowed efficient charge carrier collection, and CdSe/CdS co-sensitization enabled utilization of the visible region in the solar spectrum. PEC devices using CdSe/CdS/ZnO NW arrays showed improved absorption spectra, and they demonstrated a remarkable enhancement in PEC performance. Our proposed structure is a promising candidate photoanode for solar energy-to-hydrogen conversion devices. 相似文献
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Numerical prediction of tip vortex cavitation behavior and noise considering nuclei size and distribution 总被引:2,自引:0,他引:2
The tip vortex cavitation behavior and sound generation were numerically analyzed. A numerical scheme combining Eulerian flow field computation and Lagrangian particle trace approach was applied to simulate tip vortex cavitation. Flow field was computed by using hybrid method which combines Reynolds-Averaged Navier-Stokes solver with Dissipation Vortex Model. The trajectory and behavior of each cavitation bubble were computed by Newton’s second law and Rayleigh-Plesset equation, respectively. According to nuclei population data, the cavitation nuclei were distributed and convected into the tip vortex flow. Calculated volume of the cavitation bubble and the trajectory were used as the input of cavitation bubble noise analysis. The relationship of cavitation inception, sound pressure level, and cavitation nuclei size was studied at several cavitation numbers. It was found that cavitation inception of smaller nuclei is more sensitive to the change of cavitation number and cavitation noise due to the cavitated smallest nuclei has the most influence on overall tip vortex cavitation noise. 相似文献
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The sizes, shapes, and growth rates of gold and silver nanoparticles stabilized with polyvinylpyrrolidone in water can be
controlled by using picosecond laser pulses. The nucleation of small metal clusters formed with NaBH4 addition to produce nanoparticles takes two months with aging but 30 min with laser irradiation. Laser pulses can also induce
nanoparticles to have narrow size and shape distribution or to undergo aggregation into much larger particles. The latter
process is more likely found when the metal is silver or the irradiation wavelength is short. Laser-induced growth and shape
transformation processes are explained in terms of BH4
− depletion, metal fusion, and electron ejection followed by disintegration. 相似文献
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Irradiation (lambda > 254 nm) of matrix-isolated 2,5-diiodothiophene (10) gives rise to IR bands assigned to ethynylthioketene (6). Diethynyl sulfide (3), which would form in the process of retro-Bergman cyclization of the incipient 2,5-didehydrothiophene (4), is not detected. Under the same irradiation conditions, matrix-isolated diethynyl sulfide (3) rearranges to thioketene 6 and butatrienethione (5), the global minimum on C4H2S potential energy surface. The photochemical formation of thioketene 6 from either diyl 4 or sulfide 3 may be interpreted in line with a recent computational prediction on the thermal ring opening of diyl 4, which favors C-S bond cleavage, leading to 6, over C-C bond cleavage, leading to 3. Photolysis of matrix-isolated 3,4-thiophenedicarboxylic acid anhydride (11) enables the observation of the photoequilibration of three low-energy C4H2S isomers, butatrienethione (5), ethynylthioketene (6), and butadiynylthiol (7), via apparent [1,3]-hydrogen shifts. 相似文献
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Parker DS Zhang F Kim YS Kaiser RI Mebel AM 《The journal of physical chemistry. A》2011,115(5):593-601
The formation of polycyclic aromatic hydrocarbons in combustion environments is linked to resonance stabilized free radicals. Here, we investigated the reaction dynamics of ground state carbon atoms, C((3)P(j)), with vinylacetylene at two collision energies of 18.8 kJ mol(-1) and 26.4 kJ mol(-1) employing the crossed molecular beam technique leading to two resonantly stabilized free radicals. The reaction was found to be governed by indirect scattering dynamics and to proceed without an entrance barrier through a long-lived collision complex to reach the products, n- and i-C(5)H(3) isomers via tight exit transition states. The reaction pathway taken is dependent on whether the carbon atom attacks the π electron density of the double or triple bond, both routes have been compared to the reactions of atomic carbon with ethylene and acetylene. Electronic structure/statistical theory calculations determined the product branching ratio to be 2:3 between the n- and i-C(5)H(3) isomers. 相似文献
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Hye Jin Yun Joohyun Park Dong Hwan Ho Heyjung Kim Cy-Hyun Kim Hakjin Oh Inhwa Ga Hyemyung Seo Sunghoe Chang Ilhong Son Wongi Seol 《Experimental & molecular medicine》2013,45(8):e36
Leucine-rich repeat kinase 2 (LRRK2) is a gene that, upon mutation, causes autosomal-dominant familial Parkinson''s disease (PD). Yeast two-hybrid screening revealed that Snapin, a SNAP-25 (synaptosomal-associated protein-25) interacting protein, interacts with LRRK2. An in vitro kinase assay exhibited that Snapin is phosphorylated by LRRK2. A glutathione-S-transferase (GST) pull-down assay showed that LRRK2 may interact with Snapin via its Ras-of-complex (ROC) and N-terminal domains, with no significant difference on interaction of Snapin with LRRK2 wild type (WT) or its pathogenic mutants. Further analysis by mutation study revealed that Threonine 117 of Snapin is one of the sites phosphorylated by LRRK2. Furthermore, a Snapin T117D phosphomimetic mutant decreased its interaction with SNAP-25 in the GST pull-down assay. SNAP-25 is a component of the SNARE (Soluble NSF Attachment protein REceptor) complex and is critical for the exocytosis of synaptic vesicles. Incubation of rat brain lysate with recombinant Snapin T117D, but not WT, protein caused decreased interaction of synaptotagmin with the SNARE complex based on a co-immunoprecipitation assay. We further found that LRRK2-dependent phosphorylation of Snapin in the hippocampal neurons resulted in a decrease in the number of readily releasable vesicles and the extent of exocytotic release. Combined, these data suggest that LRRK2 may regulate neurotransmitter release via control of Snapin function by inhibitory phosphorylation. 相似文献