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991.
Yasuda M Yamasaki S Onishi Y Baba A 《Journal of the American Chemical Society》2004,126(23):7186-7187
The InCl3-catalyzed reaction of alcohols with chlorodimethylsilane (HSiMe2Cl) in the presence of benzil gave the corresponding organic chlorides under mild conditions. Benzil significantly changes the reaction course because the reducing product through dehydroxyhydration was obtained in the absence of benzil. The secondary or tertiary alcohols were effectively chlorinated. The substrates bearing acid-sensitive functional groups were also applied to this system. The highly selective chlorination of the tertiary site was observed in the competitive reaction between tertiary and primary alcohols. The highly coordinated hydrosilane generated from benzil and HSiMe2Cl is an important intermediate. 相似文献
992.
Shibata I Kato H Kanazawa N Yasuda M Baba A 《Journal of the American Chemical Society》2004,126(2):466-467
We report a one-pot synthesis of nitrogen heterocyclic compounds initiated by the allylation of the formyl group of bifunctional carbonyl compounds accompanying chemo-, regio-, and diastereoselective carbon-carbon bond formation in side chain moieties. 相似文献
993.
Fluoride complexation of element 104, rutherfordium 总被引:1,自引:0,他引:1
Haba H Tsukada K Asai M Toyoshima A Akiyama K Nishinaka I Hirata M Yaita T Ichikawa S Nagame Y Yasuda K Miyamoto Y Kaneko T Goto S Ono S Hirai T Kudo H Shigekawa M Shinohara A Oura Y Nakahara H Sueki K Kikunaga H Kinoshita N Tsuruga N Yokoyama A Sakama M Enomoto S Schädel M Brüchle W Kratz JV 《Journal of the American Chemical Society》2004,126(16):5219-5224
Fluoride complexation of element 104, rutherfordium (Rf), produced in the 248Cm(18O,5n)261Rf reaction has been studied by anion-exchange chromatography on an atom-at-a-time scale. The anion-exchange chromatographic behavior of Rf was investigated in 1.9-13.9 M hydrofluoric acid together with those of the group-4 elements Zr and Hf produced in the 18O-induced reactions on Ge and Gd targets, respectively. It was found that the adsorption behavior of Rf on anion-exchange resin is quite different from those of Zr and Hf, suggesting the influence of relativistic effects on the fluoride complexation of Rf. 相似文献
994.
M. Imamura T. Miyashita A. Tanaka H. Yasuda Y. Negishi T. Tsukuda 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,43(1-3):233-236
We have carried out optical and X-ray photoemission
studies of the dendrimer-encapsulated Au nanoclusters. The
dendrimer-encapsulated Au nanoclusters are prepared by the chemical
reduction of Au ions loaded within the dendrimer templates.
Photoluminescence spectrum of the dendrimer-encapsulated Au nanoclusters with
diameter of about 1.0 nm shows the visible luminescence centered at about
2.8 eV. In addition, we have measured the nanocluster-size dependent
photoemission spectra in the valence-band region. From line shape analysis
of Au 4f X-ray photoemission spectra, Au 4f core-level spectra of
the dendrimer-encapsulated Au nanoclusters reflect the size dependent
chemical-states. From these results, we discuss electronic structures and
chemical states of the dendrimer-encapsulated Au nanoclusters. 相似文献
995.
The diffusive permeability of water P, which relates to diffusive flux of water under a concentration gradient of water (measured by diffusion of tritiated water), and the hydraulic permeability of water K, which relates to the water flux under a hydraulic pressure gradient are defined. For the case of diffusive transport one has P = KRT/ν1, where ν1 is the molar volume of water. The relationship between P and K was investigated as a function of hydration H, i.e., the volume fraction of water in swollen polymer membranes. The following characteristic features of water permeability are revealed. (a) In the lowhydration region (H < 0.2), water permeates by diffusion even under an applied hydraulic pressure gradient and KRT/ν1 = P. (b) In the higher hydration region KRT/ν1 is greater than P, and the ratio ω = KRT/ν1P increases nearly exponentially with decrease of (1-H)/H. Water in this region moves partly by bulk flow under an applied hydraulic pressure gradient but moves only by diffusion in the absence of a pressure gradient. (c) The dependence of log P on (1-H)/H is nearly linear in regions of both high and low hydration but the slopes are different. The transition occurs in about the same H range where the discrepancy between P and KRT/ν1 becomes significant. Excellent agreement was found between the experimental data for P as a function of H and the theoretical prediction based on the free-volume concept of diffusive transport in hydrated homogeneous membranes. 相似文献
996.
Hideyuki Miura 《Journal of Functional Analysis》2005,218(1):110-129
We investigate a limiting uniqueness criterion to the Navier-Stokes equations. We prove that the mild solution is unique under the class , where bmo-1 is the “critical” space including Ln. As an application of uniqueness theorem, we also consider the local well-posedness of Navier-Stokes equations in bmo-1. 相似文献
997.
We have demonstrated a reduction of the timing jitter between passively synchronized Ti:sapphire and Cr:forsterite mode-locked lasers into a 100-attosecond (as) regime by suppressing slow fluctuations with the use of active slow-bandwidth extracavity feedback. This active-passive hybrid synchronization scheme permits the achievement of timing jitters of 98 +/- 18 as at a bandwidth of 100 kHz and of 126 +/- 20 as at a bandwidth of 1 MHz for as long as 100 s. 相似文献
998.
Long-term optical phase-coherent two-color femtosecond pulses were generated by use of passively timing-synchronized Ti:sapphire and Cr:forsterite lasers. The relative carrier-envelope phase relation was fixed by an active feedback loop. The accumulated phase noise from 10 mHz to 1 MHz of the locked beat note was 0.43 rad, showing tight phase locking. The optical frequency fluctuation between two femtosecond combs was submillihertz, with a 1 s averaged counter measurement over 3400 s, leading to a long-term femtosecond frequency-comb connection. 相似文献
999.
Izawa K Kasahara Y Matsuda Y Behnia K Yasuda T Settai R Onuki Y 《Physical review letters》2005,94(19):197002
The superconducting gap structure of recently discovered heavy fermion CePt(3)Si without spatial inversion symmetry was investigated by thermal transport measurements down to 40 mK. In zero field a residual T-linear term was clearly resolved as T --> 0, with a magnitude in good agreement with the value expected for a residual normal fluid with a nodal gap structure, together with a T2 dependence at high temperatures. With an applied magnetic field, the thermal conductivity grows rapidly, in dramatic contrast to fully gapped superconductors, and exhibits one-parameter scaling with T/sqrt[H]. These results place an important constraint on the order parameter symmetry; that is, CePt(3)Si is most likely to have line nodes. 相似文献
1000.