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991.
Yuan H Shimotani H Ye J Yoon S Aliah H Tsukazaki A Kawasaki M Iwasa Y 《Journal of the American Chemical Society》2010,132(51):18402-18407
The electric-double-layer (EDL) formed at liquid/solid interfaces provides a broad and interdisciplinary attraction in terms of electrochemistry, photochemistry, catalysts, energy storage, and electronics because of the large interfacial capacitance coupling and its ability for high-density charge accumulation. Much effort has recently been devoted to the fundamental understanding and practical applications of such highly charged EDL interfaces. However, the intrinsic nature of the EDL charging, whether it is electrostatics or electrochemistry, and how to distinguish them are far from clear. Here, by combining electrical transport measurements with electrochemical impedance spectroscopy (EIS), we studied the charging mechanisms of highly charged EDL interfaces between an ionic liquid and oxide semiconductor, ZnO. The direct measure for mobile carriers from the Hall effect agreed well with that from the capacitance-voltage integration at 1 Hz, implying that the pseudocapacitance does not contribute to carrier transport at EDL interfaces. The temperature-frequency mapping of EIS was further demonstrated as a "phase diagram" to distinguish the electrostatic or electrochemical nature of such highly charged EDL interfaces with densities of up to 8 × 10(14) cm(-2), providing a guideline for electric-field-induced electronic phenomena and a simple method for distinguishing electrostatic and electrochemical charging in EDLTs not only based on a specific oxide semiconductor, ZnO, but also commonly applicable to all types of EDL interfaces with extremely high-density carrier accumulation. 相似文献
992.
The substitution reaction of Keggin-type polyoxometalates, [XM12O40]n− (X = Si, Ge, P, or As; M = Mo or W), with vanadium(V) ion was investigated with cyclic voltammetry, Raman spectroscopy, and 31P NMR. The effect of organic solvents, such as acetonitrile (ACN), tetrahydrofuran (THF), formamide (FA), N-methylformamide (NMF), and N-methylacetoamide (NMA) on their substitution reactions was examined. In aqueous and aqueous-FA, -NMF, and -NMA solutions, the molybdenum or tungsten unit in the Keggin-anions was substituted with vanadium(V) ion to form V(V)-substituted polyoxometalates, while no substitution reaction occurred in aqueous-ACN and -THF solutions. It is suggested that this results from the relationship between the total anion charge and the permittivity of organic solvents. 相似文献
993.
A flow injection analysis (FIA) method using on-line separation and preconcentration with a novel metal scavenger beads, QuadraSil™ TA, has been developed for the ICP-OES determination of traces of palladium. QuadraSil TA contains diethylenetriamine as a functional group on spherical silica beads and shows the highest selectivity for Pd(II) at pH 1 (0.1 mol l−1 hydrochloric acid) solution. An aliquot of the sample solution prepared as 0.1 mol l−1 in hydrochloric acid was passed through the QuadraSil TA column. After washing the column with the carrier solution, the Pd(II) retained on the column was eluted with 0.05 mol l−1 thiourea solution and the eluate was directly introduced into an ICP-OES. The proposed method was successfully applied to the determination of traces of palladium in JSd-2 stream sediment certified reference material [0.019 ± 0.001 μg g−1 (n = 3); provisional value: 0.0212 μg g−1] and SRM 2556 used auto catalyst certified reference material [315 ± 4 μg g−1 (n = 4); certified value: 326 μg g−1]. The detection limit (3σ) of 0.28 ng ml−1 was obtained for 5 ml of sample solution. The sample throughputs for 5 ml and 100 μl of the sample solutions were 10 and 15 h−1, respectively. 相似文献
994.
995.
Azusa N. Hattori Fumio Kawamura Masashi Yoshimura Yasuo Kitaoka Yusuke Mori Ken Hattori Hiroshi Daimon Katsuyoshi Endo 《Surface science》2010,604(15-16):1247-1253
We studied the procedure of cleaning GaN(0001) substrate surfaces by wet etching and subsequent annealing in ultrahigh vacuum for two different types of freestanding GaN wafers: hydride vapor phase epitaxy (HVPE) crystal and Na flux liquid phase epitaxy (LPE) crystal wafers. A flat surface containing GaN(0001)2 × 2 reconstruction was successfully achieved on both HVPE and LPE surfaces by etching in HF and subsequent annealing at ~ 550 °C but was not achieved by etching in HCl, NaOH, and HNO3. 相似文献
996.
Orihara Y Kamogawa M Takeuchi A Fukase H Nagao T 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2010,86(9):914-919
Following the electric current injection experiment carried out in 2009, a VLF-MT (Very Low Frequency Magnetotelluric) survey has been conducted in Kozu-shima Island to obtain further information on the subterranean electrical structure that might help understanding the results of our monitoring of geoelectric potentials. A number of VAN-type pre-seismic geoelectric potential anomalies were observed in 1997-2000, even showing a remarkable "Selectivity". However, similar pre-seismic anomalies were not observed during the Izu-Island volcano-seismic swarm 2000. All these observations would require extremely high degree of heterogeneity in the subterranean electrical structure of the volcanic island and its possible time changes. Several correlations between the results of this survey and the volcanic geology of the island and ground water distribution were found. Further investigation is needed for a complete explanation of the observed phenomena. 相似文献
997.
C. Volk J. Schubert K. Weis S. Estévez?Hernández M. Akabori K. Sladek H. Hardtdegen T. Sch?pers 《Applied Physics A: Materials Science & Processing》2010,100(1):305-308
We investigated the properties of gadolinium scandate (GdScO3) as a gate dielectric for top-gate electrodes on undoped InAs nanowires. It is demonstrated that due to the high dielectric
constant of GdScO3 (k=22), a better control of the conductance of the nanowire is achieved compared to a reference SiO2-isolated back-gate electrode. We analyzed the output and transfer characteristics of top-gate-controlled InAs wires at room
temperature and at temperatures down to 4 K. Owing to the good coverage of the InAs nanowire by the 50-nm-thick GdScO3 layer, which was deposited by pulsed-laser deposition, the gate leakage current is sufficiently suppressed. 相似文献
998.
Tsukasa Funane Hirokazu Atsumori Hiroki Sato Masashi Kiguchi Atsushi Maki 《Optical Review》2009,16(4):442-448
The signal-to-noise ratio (SNR), when using visible or near-infrared light to measure the change in hemoglobin concentration
length (the product of hemoglobin concentration and optical path length in this study), depends on the wavelength combination
and the analysis method. Although the SNRs increase when detected or incident optical power increases, the optical power should
be limited because of safety standards. Considering these safety standards, we assumed that the total optical power was constant
by using the relationship between optical power and measurement error. We investigated the theoretical estimation errors of
the changes in hemoglobin concentration length using two, three, and four different wavelengths. The SNRs of the changes in
hemoglobin concentration length were high when fewer wavelengths were used. These SNRs decreased when the redox state change
in cytochrome oxidase was included in the analysis. 相似文献
999.
1000.
Decoherence of a qubit system interacting with a bosonic reservoir is considered when there is at most one excitation in the whole system and there is an initial correlation with the reservoir. An exact time-evolution of the system is obtained and the effect of the initial correlation on the time-evolution is examined in detail. 相似文献