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921.
Dr. Shunsuke Sato Dr. Sei'ichi Tanaka Dr. Ken-ichi Yamanaka Dr. Shu Saeki Dr. Keita Sekizawa Dr. Tomiko M. Suzuki Dr. Takeshi Morikawa Dr. Ken Onda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(3):1127-1137
A semiconductor-metal-complex hybrid photocatalyst was previously reported for CO2 reduction; this photocatalyst is composed of nitrogen-doped Ta2O5 as a semiconductor photosensitizer and a Ru complex as a CO2 reduction catalyst, operating under visible light (>400 nm), with high selectivity for HCOOH formation of more than 75 %. The electron transfer from a photoactive semiconductor to the metal-complex catalyst is a key process for photocatalytic CO2 reduction with hybrid photocatalysts. Herein, the excited-state dynamics of several hybrid photocatalysts are described by using time-resolved emission and infrared absorption spectroscopies to understand the mechanism of electron transfer from a semiconductor to the metal-complex catalyst. The results show that electron transfer from the semiconductor to the metal-complex catalyst does not occur directly upon photoexcitation, but that the photoexcited electron transfers to a new excited state. On the basis of the present results and previous reports, it is suggested that the excited state is a charge-transfer state located between shallow defects of the semiconductor and the metal-complex catalyst. 相似文献
922.
923.
J. Wang L. Zhao N. H.Luu D. Wang H. Nakashima 《Applied Physics A: Materials Science & Processing》2005,80(8):1781-1787
Zirconium (Zr) oxide films were directly deposited on Si substrate by using Ar and O2 mixed electron cyclotron resonance plasma sputtering. The structural and electrical properties of the deposited ZrO2 film were investigated in detail. According to the X-ray diffraction and Fourier transform infrared spectrometer measurements, polycrystalline films consisting of a monoclinic state were formed at substrate temperatures between 130 and 400 °C. An interfacial Si oxide layer was found and the thickness increased as the substrate temperature increased. It was found from the I–V measurement that the electrical properties of the deposited ZrO2 films were very sensitive to the O2 flow rate, and the dielectric breakdown field of 3∼5 MV/cm was achieved under the optimum condition. Permittivity of the ZrO2 film was extracted by linear fitting of the reciprocal accumulation capacitance versus oxide thickness. The permittivity was 20.5 and an interfacial Si oxide layer was 2.3 nm. Both were very consistent with the result obtained from spectroscopic ellipsometer. PACS 77.55.+f; 81.15.Cd; 52.77.Dq 相似文献
924.
Kouji KuramochiSeigo Nagata Hideyoshi ItayaYasuaki Matsubara Takashi SunokiHiromi Uchiro Ken-ichi Takao Susumu Kobayashi 《Tetrahedron》2003,59(49):9743-9758
The generation and reaction of a lactone-derived oxiranyl anion is described. The aldol-type reaction of the epoxylactone and aldehydes was accomplished by a two-step procedure via the trimethylsilyl epoxylactone. The application of this methodology to the total synthesis of (+)-epolactaene and its analogs is described. 相似文献
925.
926.
Coherent optical code division multiplexing is a novel method using the phase of optical pulse as the bipolar code for future fiber-optic communication networks. Some optical bipolar codes with a repetition frequency over 10 GHz are generated experimentally and their fundamental properties are elucidated. The key features of the method, auto- and cross-correlation of these codes, are shown experimentally and compared with the theoretical results. Interference between two optical narrow pulses with high repetition frequency is investigated experimentally under various conditions of optical phase and wavelength as the basis of the method. A guaranty of realization of the technique is shown. 相似文献
927.
Koji Niita Tatsuhiko Sato Hiroshi Iwase Hiroyuki Nose Hiroshi Nakashima Lembit Sihver 《Radiation measurements》2006,41(9-10):1080-1090
The paper presents a summary of the recent development of the multi-purpose Monte Carlo Particle and Heavy Ion Transport code System, PHITS. In particular, we discuss in detail the development of two new models, JAM and JQMD, for high energy particle interactions, incorporated in PHITS, and show comparisons between model calculations and experiments for the validations of these models. The paper presents three applications of the code including spallation neutron source, heavy ion therapy and space radiation. The results and examples shown indicate PHITS has great ability of carrying out the radiation transport analysis of almost all particles including heavy ions within a wide energy range. 相似文献
928.
Tsuneo Hirano Rei Okuda Yoshihiro Nakashima Per Jensen 《Journal of Molecular Spectroscopy》2007,243(2):202-218
We have calculated the three-dimensional potential energy surfaces for the 1 2A′ and 1 2A″ states of BrCN+ at the MR-SDCI_DK+Q/[QZP-ANO-RCC (Br, C, N)] level of theory, where MR-SDCI_DK means ‘multi-reference single and double excitation configuration interaction calculation with Douglas-Kroll Hamiltonian.’ These ab initio potential energy surfaces have a common minimum (corresponding to the state) at a linear equilibrium structure with re(Br-C) = 1.735 Å and re(C-N) = 1.199 Å. Variational RENNER calculations yield a zero-point averaged structure (with the structural parameters calculated as expectation values over rovibrational wavefunctions) with 〈r(Br-C)〉0 = 1.739 Å, 〈r(C-N)〉0 = 1.204 Å, and 〈∠(Br-C-N)〉0 = 172(4)°. A severe Fermi resonance between 2ν2 and ν3 has been found theoretically for the 2A″ potential energy surface. Comparing the ab initio zero-point averaged structure with a recent, experimentally derived r0 structure, it is concluded that the effects of large-amplitude bending motion should be taken into account explicitly in the process of deriving the r0 structure from the experimental values of the rotational constants. The electronic structure of BrCN+ has also been discussed. 相似文献
929.
Nishikawa K Wang S Katayanagi H Hayashi S Hamaguchi HO Koga Y Tozaki K 《The journal of physical chemistry. B》2007,111(18):4894-4900
1-Butyl-3-methylimidazolium bromide ([bmim]Br) and its chloride ([bmim]Cl) are representative prototypes of ionic liquids. We investigated the melting and freezing behaviors of [bmim]Br and [bmim]Cl by using a homemade differential scanning calorimeter (DSC) with nano-Watt stability and sensitivity. The measurements were carried out at heating and cooling rates slow enough to mimic quasi-static processes. Their thermal behaviors of melting and freezing show characteristic features such as a wide pre-melting range and excessive supercooling and individual behaviors of single crystals even for the same substance. The melting temperatures of [bmim]Br and [bmim]Cl were determined from the broad DSC traces and discussed in relation to the crystal structure. We suggest that the observed characteristics are due to the dynamics of the cooperative change between gauche-trans (GT) and trans-trans (TT) conformations of the butyl group in the [bmim]+ cation. 相似文献
930.