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131.
Naoya Nishi Daisuke Hobara Masahiro Yamamoto Takashi Kakiuchi 《Analytical sciences》2003,19(6):887-890
Sum frequency vibrational spectra for hexadecanethiol (HDT) adsorbed on thin gold film deposited on the surface of a CaF2 prism have been measured using total-internal reflection broad-bandwidth sum frequency generation (TIR-BBSFG) spectroscopy. The bands attributed to the CH3 symmetric and asymmetric stretching vibrational modes were observed in the sum frequency vibrational spectra. The orientation of the methyl groups was analyzed using the ratio of the intensities of the two modes. The methyl groups of HDT on the thin gold film were much more randomly orientated than those on Au( 111). 相似文献
132.
Nagaoka S Fukuzawa H Prümper G Takemoto M Takahashi O Yamaguchi K Kakiuchi T Tabayashi K Suzuki IH Harries JR Tamenori Y Ueda K 《The journal of physical chemistry. A》2011,115(32):8822-8831
In an aim to create a "sharp" molecular knife, we have studied site-specific fragmentation caused by Si:2p core photoionization of bridged trihalosilyltrimethylsilyl molecules in the vapor phase. Highly site-specific bond dissociation has been found to occur around the core-ionized Si site in some of the molecules studied. The site specificity in fragmentation and the 2p binding energy difference between the two Si sites depend in similar ways on the intersite bridge and the electronegativities of the included halogen atoms. The present experimental and computational results show that for efficient "cutting" the following conditions for the two atomic sites to be separated by the knife should be satisfied. First, the sites should be located far from each other and connected by a chain of saturated bonds so that intersite electron migration can be reduced. Second, the chemical environments of the atomic sites should be as different as possible. 相似文献
133.
Jean Cardinal Erik D. Demaine Martin L. Demaine Shinji Imahori Tsuyoshi Ito Masashi Kiyomi Stefan Langerman Ryuhei Uehara Takeaki Uno 《Graphs and Combinatorics》2011,27(3):341-351
How do we most quickly fold a paper strip (modeled as a line) to obtain a desired mountain-valley pattern of equidistant creases (viewed as a binary string)? Define the folding complexity of a mountain-valley string as the minimum number of simple folds required to construct it. We first show that the folding complexity of a length-n uniform string (all mountains or all valleys), and hence of a length-n pleat (alternating mountain/valley), is O(lg2 n). We also show that a lower bound of the complexity of the problems is ??(lg2 n/lg lg n). Next we show that almost all mountain-valley patterns require ??(n/lg n) folds, which means that the uniform and pleat foldings are relatively easy problems. We also give a general algorithm for folding an arbitrary sequence of length n in O(n/lg n) folds, meeting the lower bound up to a constant factor. 相似文献
134.
Effect of high CO2 concentration on char formation through mineral reaction during biomass pyrolysis
Hirotatsu Watanabe Kiyomi Shimomura Ken Okazaki 《Proceedings of the Combustion Institute》2013,34(2):2339-2345
O2/CO2 combustion has attracted considerable attention as a promising technology for CO2 capture. Using biomass for fuel is considered carbon neutral, and O2/CO2 biomass combustion can mitigate the deleterious environmental effect of greenhouse. In this study, the effect of CO2, the main component gas in O2/CO2 combustion, on the pyrolysis characteristics of biomass is investigated. Cellulose, lignin, and metal-depleted lignin pyrolysis experiments were performed using a thermobalance. Information on the surface chemistry of the chars was obtained by Fourier transform infrared (FTIR) spectroscopy to investigate changes in the surface chemistry during pyrolysis under different surrounding gasses. When the temperature increased to 1073 K at heating rate of 1 K s?1, the char yield of lignin in the presence of CO2 increased by about 10% compared with that under Ar. However, for cellulose and metal-depleted lignin, no significant difference appeared between pyrolysis under CO2 and that under Ar. FT-IR showed that a strong peak corresponding to carbonate ions appeared in the char derived from lignin under CO2. Therefore, salts such as Na2CO3 or K2CO3 formed during the lignin pyrolysis under CO2. At around 1650–1770 cm?1, a significant difference appeared in the FTIR spectra of chars formed under CO2 and those formed under Ar. C=O groups not associated with an aromatic ring were found only in chars formed under CO2. It was suggested that these salts affected the char formation reaction, in that the char formed during lignin pyrolysis under CO2 had unique chemical bands that did not appear in the lignin-derived char prepared under Ar. 相似文献
135.
Atsushi Umeya Takayuki Myo Emiko Hiyama Hiroshi Toki Kiyomi Ikeda 《Few-Body Systems》2013,54(1-4):99-102
The Λ N–ΣN coupling is one of the open questions in strangeness physics. We studied the Λ N–ΣN coupling explicitly in light s-shell hypernuclei using Tensor Optimized Shell Model, which is ab initio like approach starting from the realistic interaction. We show the obtained results of s-shell Λ-hypernuclei, Λ 4 H and Λ 5 He, and investigate the roles of the Λ N–ΣN coupling interaction in those hypernuclei. 相似文献
136.
Atsushi Umeya Takayuki Myo Emiko Hiyama Hiroshi Toki Kiyomi Ikeda 《Few-Body Systems》2013,54(7-10):1215-1217
The explicit ΛN ? ΣN coupling in s-shell hypernuclei is studied by using the tensor-optimized shell model. We show the obtained results of s-shell hypernuclei, ${_{\Lambda}^{4}{\rm H}}$ and ${_{\Lambda}^{5}{\rm He}}$ , and investigate the roles of the ΛN ? ΣN coupling interaction in those hypernuclei. 相似文献
137.
“Nondissociative” chain walking is a mechanism where an alkylmetal species undergoes rapid β-hydride elimination and reinsertion to move the metal center along the alkyl chain without dissociating an alkene intermediate during the migration process. This digest summarizes the unique characteristics of the nondissociative chain walking mechanism compared to the stepwise alkene isomerization mechanism and their use in catalytic organic synthesis. 相似文献
138.
Takuya Kochi Kazuya Ichinose Masayuki Shigekane Taro Hamasaki Fumitoshi Kakiuchi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(16):5315-5319
Sequential formation of distant bonds in organic molecules was achieved for the palladium‐catalyzed hydrosilylation/cyclization of various 1,n‐dienes by chain walking of the metal catalyst. The reaction was applicable to various 1,n‐dienes, including a 1,13‐diene, to form a cyclopentane ring as well as a carbon–silicon bond at a remote site. The use of “nondissociative” chain walking provides a fascinating strategy in organic synthesis to functionalize distant parts of organic molecules, in a particular order, within a catalytic cycle by effectively moving the reactive center from a remote position. 相似文献
139.
Nomoto Akihiro Sakamoto Nozomi Sakai Yuta Fukumoto Keisuke Ogura Shun-Ichiro Shouhei Katao Kakiuchi Kiyomi Kikuchi Jun-ichi Yano Shigenobu Ogawa Akiya 《Research on Chemical Intermediates》2019,45(1):3-12
Research on Chemical Intermediates - Phenylalanine ester-introduced palladium(II) and platinum(II) complexes were synthesized. Taking advantage of the formation of Schiff bases by amino acids as an... 相似文献
140.
Laforge FO Kakiuchi T Shigematsu F Mirkin MV 《Langmuir : the ACS journal of surfaces and colloids》2006,22(25):10705-10710
Molecular partitioning and electron-transfer kinetics have been studied at the ionic liquid/water (IL/water) interface by scanning electrochemical microscopy (SECM). The ionic liquid C8mimC1C1N is immiscible with water and forms a nonpolarizable interface when in contact with it. Partitioning of ferrocene (Fc) across the IL/water interface was studied by SECM and found to be kinetically fast with a partition coefficient CIL/CW of 2400:1. The partition coefficient value was measured by SECM under quasi-steady-state conditions without waiting for complete solute equilibration. To investigate the kinetics of the electron transfer (ET) between aqueous ferricyanide and Fc dissolved in IL, a new approach to the analysis of the SECM current-distance curves was developed to separate the contributions of Fc partitioning and the ET reaction to the tip current. Several combinations of different aqueous and nonaqueous redox species were investigated; however, only the Fc/Fe(CN)63- system behaved according to the Butler-Volmer formalism over the entire accessible potential range. 相似文献