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511.
Jarrige I Rueff JP Shieh SR Taguchi M Ohishi Y Matsumura T Wang CP Ishii H Hiraoka N Cai YQ 《Physical review letters》2008,101(12):127401
The pressure-induced valence transition in TmTe was investigated by resonant inelastic x-ray scattering at the Tm L3 edge, a powerful probe of the rare-earth valent state. The data are analyzed within the Anderson impurity model which yields key parameters such as the Tm 4f-5d hybridization. In addition to the general tendency of the f electrons towards delocalization, we find a plateau in both the Tm valence and hybridization pressure dependences between 4.3 and 6.5 GPa which is interpreted in terms of an n-channel Kondo (NCK) screening process. This behavior is at odds with the usually continuous, single-channel Kondo-like f delocalization while being supported by the seminal calculations of the NCK temperature in Tm ion by Saso et al. Our study raises the interesting possibility that an NCK effect realized in a compressed mixed-valent f system could impede the concomitant electron delocalization. 相似文献
512.
A k-tree of a graph is a spanning tree with maximum degree at most k. We give sufficient conditions for a graph G to have a k-tree with specified leaves: Let k,s, and n be integers such that k≥2, 0≤s≤k, and n≥s+1. Suppose that (1) G is (s+1)-connected and the degree sum of any k independent vertices of G is at least |G|+(k−1)s−1, or (2) G is n-connected and the independence number of G is at most (n−s)(k−1)+1. Then for any s specified vertices of G, G has a k-tree containing them as leaves. We also discuss the sharpness of the results.
This research was partially supported by the Ministry of Education, Science, Sports and Culture, Grant-in-Aid for Encouragement
of Young Scientists, 15740077, 2005
This research was partially supported by the Japan Society for the Promotion of Science for Young Scientists. 相似文献
513.
Steven P. Davis Masashi Matsumura Andreia Williams Thomas M. Nordlund 《Journal of fluorescence》2003,13(3):249-259
The fluorescent probe/base, 2-aminopurine (2AP), has been incorporated into DNA pentamers that otherwise contain only adenine, the base that has been shown to stack strongly with itself and with the adenine mimic, 2AP. The probe base has been placed in each of the five positions in single strands. Optical spectral shifts, energy-transfer efficiencies, and their respective temperature dependencies behave simply as a function of 2AP position: those quantities approximately double when 2AP is placed between two adenines, compared to 2AP at either end of the chain. Transfer efficiencies of 80% (at 5°C) are measured for APAAA and AAPAA, 68% for AAAPA, while PAAAA and AAAAP efficiencies are 52% and 46%, respectively (P = 2AP). The spectroscopic parameters are therefore reliable measures of local DNA conformation that can be interpreted in a straightforward manner in terms of interbase electronic interactions. Interactions of 2AP with nonadenine bases have previously been shown to mostly be much weaker. 相似文献
514.
Abedien Zabardasti Nahla Talebi Ali Kakanejadifard Zeinab Saki 《Structural chemistry》2016,27(2):573-581
Ab initio calculations were used to analyze the interaction of C4B2H6 with HF and LiH molecules at the mp2/6-311++g(2d,2p) computational level. Interaction of C4B2H6 with HF results to H–F···H–C and C–B···H–F, C–C···H–F hydrogen bond as well as B–H···H–F dihydrogen bond complexes. Also interaction of C4B2H6 with LiH results to B–C···LiH, C–C···LiH and B–H···LiH lithium bond as well as C–H···H–Li dihydrogen complexes. In the both cases, complexes involving interaction of HF or LiH with peripheral B–C and C–C bonds of the C4B2H6 backbone have greater stabilities. The structures of complexes have been analyzed using AIM and NBO methodologies. 相似文献
515.
Dr. Yoshimasa Matsumura Makoto Ishidoshiro Dr. Yasuyuki Irie Dr. Hiroaki Imoto Prof. Dr. Kensuke Naka Prof. Dr. Kazuyoshi Tanaka Prof. Dr. Shinsuke Inagi Prof. Dr. Ikuyoshi Tomita 《Angewandte Chemie (International ed. in English)》2016,55(48):15040-15043
A synthetic method to obtain an arsole‐containing π‐conjugated polymer by the post‐transformation of the organotitanium polymer titanacyclopentadiene‐2,5‐diyl unit with an arsenic‐containing building block is described. The UV/Vis absorption maximum and onset of the polymer were observed at 517 nm and 612 nm, respectively. The polymer exhibits orange photoluminescence with an emission maximum (Emax) of 600 nm and the quantum yield (Φ) of 0.05. The polymer proved to exhibit a quasi‐reversible redox behavior in its cyclic voltammetric (CV) analysis. The energy levels of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) were estimated to be ?5.43 and ?3.24 eV, respectively, from the onsets for oxidation and reduction signals in the CV analysis. Further chemical modification of the arsole unit in the π‐conjugated polymer by complexation of gold(I) chloride occurred smoothly resulting in the bathochromic shift of the UV/Vis absorption and lowering of the LUMO energy level. 相似文献
516.
Masashi Kawasaki Saki Kuroyanagi Takuya Ito Hiroyuki Morita Yasuo Tanaka Naoki Toyooka 《Tetrahedron》2017,73(15):2089-2099
Phantolide analogues 1a–1d were newly synthesized to evaluate their odor profiles. The enantiomers of 1a and 1b were also synthesized. Both (S) enantiomers of 1a and 1b had musk odor although weakly, and but neither of the (R) enantiomers 1a and 1b had musk odor. During the investigations, we encountered the undesirable racemization in Friedel-Crafts reaction of the intermediate (S)-5. 相似文献
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520.
Shuichi Matsumura Yasuhiro Tsushima Nobuyuki Otozawa Saeko Murakami Kazunobu Toshima Graham Swift 《Macromolecular rapid communications》1999,20(1):7-11
Diethyl L ‐aspartate was polymerized by proteinase at a temperature between 4 and 50°C to yield poly(ethyl α,β‐L ‐aspartate). Bulk polymerization of diethyl L ‐aspartate, especially at temperatures between 40 and 50°C, and preferably using alkalophilic proteinase with the addition of a small amount of water gave poly(ethyl L ‐aspartate) as a white powder with a molecular weight of up to 3 600 and having about 88% α‐linkages. 相似文献