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241.
Atsushi Shinohara Toshiharu Muroyama Junichirou Shintai Eugene Taniguchi Tadashi Saito Taichi Miura Nobutsugu Imanishi Yoshio Yoshimura Michiaki Furukawa 《Hyperfine Interactions》1994,84(1):569-574
The transfer of negative pions captured by hydrogen to heavier atoms has been investigated in a series of alcohols by measuring both 2 rays from 0 decay and pionic X rays. Capture rates for the pionic hydrogen of different chemical states in the molecule were determined from a comparison between the data for the ordinary compound and the deuterated one. The external transfer in the condensed phase was revealed by the dependence of the capture rate of hydrogen on the number of carbon atoms in the alkyl group. The influence of the chemical structure on the transfer process is discussed with respect to the large difference between the relative transfer rates,
C=1.5±0.2 and
O = 4.5±0.4, corresponding to carbon and oxygen, respectively. 相似文献
242.
To elucidate allometric scaling in complex systems, we investigated the underlying scaling relationships between typical three-scale indicators for approximately 500,000 Japanese firms; namely, annual sales, number of employees, and number of business partners. First, new scaling relations including the distributions of fluctuations were discovered by systematically analyzing conditional statistics. Second, we introduced simple probabilistic models that reproduce all these scaling relations, and we derived relations between scaling exponents and the magnitude of fluctuations. 相似文献
243.
We develop the classification and systematic construction of all possible untwisted D-branes in Lie groups of A-D-E series. D-branes are classified according to their positions in the maximal torus. We construct all untwisted singular D-branes by the method of iterative deletion in the Dynkin diagram and count their dimensions, which turn out to be always even numbers. 相似文献
244.
Taichi Nakano Kenji Kawai Takanori Endoh Shintaro Osada Takashi Miyamoto 《应用有机金属化学》2005,19(9):1043-1046
The Pd(dba)2‐catalyzed reaction of Z‐1‐aryl‐1‐(tributylstannyl)‐2‐(trimethylsilyl)ethenes with allyl bromide in the presence of copper(I) iodide is reported for the first time. The reaction in the presence of 0.5 mol% Pd(dba)2 and 8 mol% CuI in dimethylformamide takes place at room temperature to give E‐2‐aryl‐1‐(trimethylsilyl)penta‐1,4‐dienes exclusively in isolated yields of 62–99%. A putative reaction mechanism is proposed. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
245.
Circularly Polarized Luminescence of Chiral Pt(pppb)Cl (pppbH=1‐pyridyl‐3‐(4,5‐pinenopyridyl)benzene) Aggregate in the Excited State
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Saori Tanaka Dr. Kyohei Sato Kyoko Ichida Dr. Taichi Abe Prof. Taro Tsubomura Prof. Takayoshi Suzuki Prof. Kazuteru Shinozaki 《化学:亚洲杂志》2016,11(2):265-273
We prepared enantiomers of chiral PtII complexes, Pt(pppb)Cl and Pt(pppb)CN (pppbH=1‐pyridyl‐3‐(4,5‐pinenopyridyl)benzene), and measured their CPL (circularly polarized luminescence) spectra for excimer and trimer emission. The contribution of the pinene moiety to CPL was considerably low for the π–π* emission of the monomer but large for MMLCT (metal‐metal‐to‐ligand charge‐transfer) of the excimer and trimer which had a helical structure induced in a face‐to‐face stacking fashion. The trimer CPL for (+)‐Pt(pppb)Cl was larger in intensity than that of excimer CPL; on the other hand, that for (+)‐Pt(pppb)CN was opposite in sign compared with that of excimer CPL. We conclude that differences in the excited‐state structure of the aggregate between Pt(pppb)Cl and Pt(pppb)CN account for the variation in the CPL spectra. By the aid of TD‐DFT calculations it was predicted that the dihedral angle θ(Cl‐Pt‐Pt‐Cl) was 50–60° or 110–140° for Pt(pppb)Cl aggregates and 160° for Pt(pppb)CN aggregates. 相似文献
246.
Nobuyasu Hanari Nobuyasu Itoh Taichi Yamazaki Naomi Fujiki Ryoko Iwasawa Masahiko Numata 《Accreditation and quality assurance》2013,18(2):137-142
The composition of impurities in perfluorooctanoic acid (PFOA) was measured and determined to be notably different between lots. Since the purity of PFOA varied, the accuracy of prepared calibration solution concentrations was reduced. In this study, factors influencing the purity were investigated using a Karl Fischer titrator and a LC/MS to support the development of reference materials. The results showed variances of water and isomer/homologue contents under different ambient conditions during sample handling. Moreover, these variances, especially for water, greatly affected the purity of PFOA (0.95–0.99 kg kg?1). Therefore, PFOA of reliable purity should be used for the preparation of calibration solutions. 相似文献
247.
Taichi Usui Makoto Ogata Takeomi Murata Kazuhiro Ichikawa Yoshiyuki Sakano Yasunori Nakamura 《Journal of carbohydrate chemistry》2013,32(7-8):421-430
Negative ion Q-TOF MS/MS spectra are shown to be very useful for sequential analysis of the glycosidic linkage in the α-gluco-oligosaccharides (DP 3-6) derived from an amylopectin molecule. The composition of the fragmentation ions generated from these compounds enabled us to distinguish two kinds of glycosidic linkage, α-(1→4) and α-(1→6), at same time to determine the glucose sequence from the reducing end of the oligosaccharide. 相似文献
248.
Taichi Kano 《Tetrahedron》2010,66(26):4900-1633
Catalytic asymmetric synthesis of various cyclic α-alkyl-amino acid derivatives having a tetrasubstituted α-carbon, such as α-alkylprolines has been accomplished by asymmetric phase-transfer C-alkylation of α-alkyl-amino acid derivatives and subsequent intramolecular N-alkylation. 相似文献
249.