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31.
Tsuyoshi Satoh Takayuki Kuramoto Shingo Ogata Hiroyuki Watanabe Takahito Saitou Makoto Tadokoro 《Tetrahedron: Asymmetry》2010,21(1):1-5
Treatment of enantiomerically pure 1-chlorovinyl p-tolyl sulfoxides, derived from cyclic ketones and (R)-chloromethyl p-tolyl sulfoxide, with the lithium enolate of tert-butyl carboxylates gave adducts in quantitative yields as single diastereomers. The adducts were treated with i-PrMgCl in toluene to afford optically active bicyclo[n.1.0]alkanes bearing a tert-butyl carboxylate moiety in up to 99% enantiomeric excess through the enantioselective 1,3-CH insertion reaction of the generated chiral magnesium carbenoids. This is the first example of the enantioselective 1,3-CH insertion reaction of magnesium carbenoid. 相似文献
32.
Kato D Masaike M Majima T Hirata Y Mizutani F Sakata M Hirayama C Kunitake M 《Chemical communications (Cambridge, England)》2002,(22):2616-2617
Novel two-dimensional (2D) cross-linked polysiloxane LB films were prepared and applied for glucose sensing as H2O2-permselective films in order to block other electroactive interferences, such as L-ascorbic acid, L-cysteine, uric acid and acetaminophen; the 2D cross-linked polysiloxane monolayers were remarkably effective in eliminating interfering responses and had a rapid response for glucose, even though the films were only a monolayer thick. 相似文献
33.
Annealing behaviors of photo-induced ESR and optically-induced absorption edge shift have been studied in melt-quenched Ge-S glasses with various compositions. Annealing characteristic of photo-induced ESR has been found to be quite parallel to that of optically-induced edge shift. Composition dependence of them is correlated with that of the glass transition temperature. 相似文献
34.
Kakuyanagi K Saitoh M Kumagai K Takashima S Nohara M Takagi H Matsuda Y 《Physical review letters》2005,94(4):047602
We present a 115In NMR study of the quasi-two-dimensional heavy-fermion superconductor CeCoIn5 believed to host a Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) state. In the vicinity of the upper critical field and with a magnetic field applied parallel to the ab plane, the NMR spectrum exhibits a dramatic change below T*(H) which well coincides with the position of reported anomalies in specific heat and ultrasound velocity. We argue that our results provide the first microscopic evidence for the occurrence of a spatially modulated superconducting order parameter expected in a FFLO state. The NMR spectrum also implies an anomalous electronic structure of vortex cores. 相似文献
35.
The hydrothermal synthesis, single crystal X-ray structures and magnetic properties of two layered cobalt-carboxylate complexes, ∞2[CoII(O2C∗CH(OH)C6H5)2] (1) and ∞2[CoII(O2C∗CH(NH2)C6H5)2] (2), where O2CCH(OH)C6H5 is mandalate and O2CCH(NH2)C6H5 is phenylglycinate, are described. Pale pink crystals of 1 and 2 were obtained by the reaction of cobalt nitrate and the enantiomer-pure acids at 120 °C. In each case, the structure consists of stacks of quasi square-grid polymeric sheets consisting of carboxylato- bridges, M-O-C-O-M, and the presence of both d- and l-enantiomers of the ligands segregated on each face of the layer. The ligands exhibit both chelating and bridging functions with the carboxylate group adopting an anti-anti mode. The magnetic properties are characteristic of weakly interacting paramagnets where the moments are elevated by an important orbital contribution via spin-orbit coupling. 相似文献
36.
Shigendo Enomoto Ken-ichi Kumagai Taro Tamura Miki Hasegawa Kyoko Nakada Toshihiko Hoshi Michio Kobayashi 《Monatshefte für Chemie / Chemical Monthly》2004,29(1):471-481
Fluoranthene (FA) forms a 1:1 van der Waals complex with benzene in cyclohexane. The 1H NMR spectrum of this complex shows that the FA moiety in the complex state has five kinds of hydrogen atoms and that the 1H NMR peaks assigned to the protons attached to the naphthalene skeleton are largely shifted to higher magnetic field on complex formation with benzene. These observations indicate that the complex takes the structure of CS symmetry, in which the benzene molecule mainly interacts with the electronic system localized on the naphthalene moiety of FA. The present ab initio calculations reproduce well the 1H NMR spectral shifts mentioned above and the experimentally predicted CS structure of the complex. According to the PPP calculations for the electronic absorption spectral changes on the complex formation, the FA-benzene complex is considered to take a sandwich type structure. 相似文献
37.
Zegers RG Sumihama M Ahn DS Ahn JK Akimune H Asano Y Chang WC Daté S Ejiri H Fujimura H Fujiwara M Hicks K Hotta T Imai K Ishikawa T Iwata T Kawai H Kim ZY Kino K Kohri H Kumagai N Makino S Matsumura T Matsuoka N Mibe T Miwa K Miyabe M Miyachi Y Morita M Muramatsu N Nakano T Niiyama M Nomachi M Ohashi Y Ooba T Ohkuma H Oshuev DS Rangacharyulu C Sakaguchi A Sasaki T Shagin PM Shiino Y Shimizu H Sugaya Y Toyokawa H Wakai A Wang CW Wang SC Yonehara K Yorita T Yoshimura M Yosoi M 《Physical review letters》2003,91(9):092001
Beam polarization asymmetries for the p(gamma-->,K+)Lambda and p(gamma-->,K+)Sigma(0) reactions are measured for the first time for E(gamma)=1.5-2.4 GeV and 0.6相似文献
38.
S.-H. Cho H. Kumagai K. Midorikawa 《Applied Physics A: Materials Science & Processing》2003,76(5):755-761
The time-resolved dynamics of plasma self-channeling and refractive index bulk modification in silica glasses were first observed
in situ using a high-intensity femtosecond (110 fs) Ti:sapphire laser (λp=790 nm). Plasma channeling is induced in silica glass at an irradiation higher than an input intensity of 1.5×1012 W/cm2 and photoinduces either the refractive-index modification or optical crack modification. In the domain of refractive-index
modification, the lifetime of induced plasma self-channeling was 20 ps and the structural transition time for forming the
refractive-index change was 10 ps. In the domain of optical cracks, however, the lifetime of induced plasma formation was
30 ps and the structural transition time for forming the optical cracks was 40 ps. According to electron spin resonance spectroscopic
(ESP) measurement, it was found that the defect concentration of the SiE′ center increased significantly in the refractive index modification region. A maximum value of the refractive-index change
Δn was measured to be 1.6×10-2. The intensity profile of the output beam transmitted through the refractive-index modification showed that the bulk modification
produced a permanent optical waveguide.
Received: 8 April 2002 / Accepted: 12 April 2002 / Published online: 22 November 2002
RID="*"
ID="*"Corresponding author. Fax: +81-48/462-4682, E-mail: shcho@riken.go.jp 相似文献
39.
40.
We developed a deep-UV single-mode coherent light source through two-stage highly efficient frequency conversions by use of external cavities. In the first stage, second-harmonic power of 500 mW was obtained by frequency doubling of a 746-nm Ti:sapphire laser with a conversion efficiency of 40%. In the second stage, 50-mW power at ~252nm was obtained by doubly resonant sum-frequency mixing of 373-nm light from the first-stage conversion and 780-nm light from a diode laser. The output performance of this deep-UV light source is sufficient for laser cooling of neutral silicon atoms. 相似文献