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991.
Choi YC Lee HM Kim WY Kwon SK Nautiyal T Cheng DY Vishwanathan K Kim KS 《Physical review letters》2007,98(7):076101
On the basis of first-principles calculations of clusters and one dimensional infinitely long subnanowires of the binary systems, we find that alkali-noble metal alloy wires show better linearity and stability than either pure alkali metal or noble metal wires. The enhanced alternating charge buildup on atoms by charge transfer helps the atoms line up straight. The cesium doped gold wires showing significant charge transfer from cesium to gold can be stabilized as linear or circular monoatomic chains. 相似文献
992.
Lee JW Park JA Lee JJ Bae SJ Lee SH Jung JC Kim MN Lee J Woo S Chang Y 《Magnetic resonance imaging》2007,25(5):652-656
Recent studies have demonstrated the use of manganese ion (Mn2+)) as an in vivo neuronal tract tracer. In contrast to histological approaches, manganese tracing can be performed repeatedly on the same living animal. In this study, we describe the neuroaxonal tracing of the auditory pathway in the living guinea pig, relying on the fact that Mn2+ ion enters excitable cells through voltage-gated calcium channels and is an excellent MRI paramagnetic tract-tracing agent. Small focal injections of Mn2+ ion into the cochlea produced significant contrast enhancement along the known neuronal circuitry. This in vivo approach, allowing repeated measures, is expected to open new vistas to study auditory physiology and to provide new insights on in vivo axonal transport and neuronal activity in the central auditory system. 相似文献
993.
Corrosion behaviors and surface profiles of platinum (Pt)-coated electrodes were investigated by electrochemistry and complementary microscopy. Four types of needle electrodes (Pt/titanium, Pt/tungsten, Pt/brass, and Pt/stainless steel) were prepared by unbalanced magnetron sputtering and subjected to the potentiodynamic polarization test in 0.9% deaerated sodium chloride solution at room temperature. The potentiodynamic test revealed that Pt/Ti electrodes had the highest corrosion resistance among the electrodes tested in this study, with the corrosion potential of 228mV(SCE) and the corrosion rate of 0.10 microA/cm(2). Morphology and surface profiles of the electrodes examined by reflected light, electron, and atomic force microscopy were consistent with those of corrosion resistance, showing that the electrodes with higher corrosion resistance had lower surface roughness than others. It is likely that the electrodes with higher corrosion resistance have suffered slower dissolution of substrates, and consequently had less cavities and/or corrosion products. Furthermore, nude mice inoculated with a bronchoalveolar cancer cell line and exposed to direct electric field showed the deterioration of proliferated tumor cells, proving the efficacy of electrochemical treatment. These results suggest that either Pt/Ti or Pt/W electrodes for solid tumors are suitable to be employed in the electrochemical treatment of tumors for anticancer therapy, applying low-level direct current due to their high corrosion resistance. 相似文献
994.
Treatment of unsaturated 1,5-diols 2 with TES-Cl (1.1 equiv), imidazole, and catalytic DMAP in 1:1 CH2Cl2-DMF at -78 degrees C effects selective silylation of the allylic alcohol with >95:5 chemoselectivity when the allylic and homoallylic alcohols are in similar steric environments. 相似文献
995.
996.
Guanidine-containing molecular transporters: sorbitol-based transporters show high intracellular selectivity toward mitochondria 总被引:1,自引:0,他引:1
997.
This paper reports the pH-induced structural changes in the surface immobilized poly(L-lysine)(PLL)film.Two-dimensional(2D) correlation analysis was applied to the Fourier transform infrared(FTIR)spectra of the surface-immobilized PLL film to examine the spectral changes induced by the alternations of the protonation state of the amino group in the side chain.Significant spectral changes in the FTIR spectra of the PLL film were observed between pH 7 and 8.The decrease in the protonation state of the amino group in the side chain induced spectral changes in the amino group as well as conformational changes in the alky]group in the side chain.From pH 1-8,the spectral changes in the amino and alkyl groups in the side chain occurred before those of the amide group in the main chain of the surface immobilized PLL film. 相似文献
998.
Coating on Zinc Surface to Improve the Electrochemical Behavior of Zinc Anodes for Zinc‐Air Fuel Cells 下载免费PDF全文
The corrosion of Zn anode, associated with corrosion current and hydrogen evolution reaction, is a major reason for capacity loss and safety problems. As a way of improving the current issue, a newly coating method using difference of melting points has been attempted to synthesize anode materials and found to be highly effective. Effects of corrosion inhibitors are also investigated by diverse electrochemical techniques. The Tafel extrapolation shows the reduced corrosion current compared with that of pure Zn. ZnNi‐2 (Zn:Ni, 95 : 5 wt.%) demonstrates the hydrogen overpotential is shifted to the most negative value as ?1.7 V vs. Hg/HgO. 相似文献
999.
A thin film of polyflourene polymer was sandwiched between a conductive polymer deposited on silver nanowire and metal electrode to form a multilayer polymer‐based diode device. The electrical properties of fabricated polymeric diode have been studied by current–voltage method. The current–voltage characteristics of the fabricated device exhibited non‐ideal, asymmetrical, and rectifying behavior. Ohmic current conduction mechanism was observed in the device at low voltage. At higher voltage values, the space‐charge‐limited current conduction mechanism was found to be dominated. The values of the Schottky barrier height, ideality factor, and saturation current density were extracted according to the standard thermionic emission model and discussed. The barrier height and ideality factor were calculated as 0.72 eV and 2.53, respectively. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
1000.
Dr. Soumen Dutta Dr. Nitee Kumari Dr. Sateesh Dubbu Sun Woo Jang Dr. Amit Kumar Dr. Hiroyoshi Ohtsu Junghoon Kim Prof. Seung Hwan Cho Prof. Masaki Kawano Prof. In Su Lee 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(9):3444-3450
Rational engineering and assimilation of diverse chemo- and biocatalytic functionalities in a single nanostructure is highly desired for efficient multistep chemical reactions but has so far remained elusive. Here, we design and synthesize multimodal catalytic nanoreactors (MCNRs) based on a mesoporous metal-organic framework (MOF). The MCNRs consist of customizable metal nanocrystals and stably anchored enzymes in the mesopores, as well as coordinatively unsaturated cationic metal MOF nodes, all within a single nanoreactor space. The highly intimate and diverse catalytic mesoporous microenvironments and facile accessibility to the active site in the MCNR enables the cooperative and synergistic participation from different chemo- and biocatalytic components. This was shown by one-pot multistep cascade reactions involving a heterogeneous catalytic nitroaldol reaction followed by a [Pd/lipase]-catalyzed chemoenzymatic dynamic kinetic resolution to yield optically pure (>99 % ee) nitroalcohol derivatives in quantitative yields. 相似文献