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141.
[reaction: see text] A new method is presented for the measurement of enantiomeric excess (ee) utilizing molecularly imprinted polymers (MIPs). The method is demonstrated to be accurate and rapid, as the ee values can be calculated from straightforward concentration measurements. The MIP-based assay can also be adapted to measure the ee of samples of differing initial concentrations. 相似文献
142.
Shimizu Y Shiokawa N Yamamoto N Kozuma M Kuga T Deng L Hagley EW 《Physical review letters》2002,89(23):233001
Propagation of a light pulse through a high-Q optical microcavity containing a few cold atoms (N<10) in its cavity mode is investigated experimentally. With less than ten cold rubidium atoms launched into an optical microcavity, up to 170 ns propagation lead time ("superluminal"), and 440 ns propagation delay time (subluminal) are observed. Comparison of the experimental data with numerical simulations as well as future experiments are discussed. 相似文献
143.
Surface-enhanced emission from single semiconductor nanocrystals 总被引:1,自引:0,他引:1
The fluorescence behavior of single CdSe(ZnS) core-shell nanocrystal (NC) quantum dots is dramatically affected by electromagnetic interactions with a rough metal film. Observed changes include a fivefold increase in the observed fluorescence intensity of single NCs, a striking reduction in their fluorescence blinking behavior, complete conversion of the emission polarization to linear, and single NC exciton lifetimes that are >10(3) times faster. The enhanced excited state decay process for NCs coupled to rough metal substrates effectively competes with the Auger relaxation process, allowing us to observe both charged and neutral exciton emission from these NC quantum dots. 相似文献
144.
Feng DL Damascelli A Shen KM Motoyama N Lu DH Eisaki H Shimizu K Shimoyama Ji JI Kishio K Kaneko N Greven M Gu GD Zhou XJ Kim C Ronning F Armitage NP Shen ZX 《Physical review letters》2002,88(10):107001
The low-energy electronic structure of the nearly optimally doped trilayer cuprate superconductor Bi(2)Sr(2)Ca(2)Cu(3)O(10+delta) is investigated by angle-resolved photoemission spectroscopy. The normal state quasiparticle dispersion and Fermi surface and the superconducting d-wave gap and coherence peak are observed and compared with those of single- and bilayer systems. We find that both the superconducting gap magnitude and the relative coherence-peak intensity scale linearly with T(c) for various optimally doped materials. 相似文献
145.
Hashi K Shimizu T Goto A Kiyoshi T Matsumoto S Wada H Fujito T Hasegawa K Yoshikawa M Miki T Ito S Hamada M Hayashi S 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2002,156(2):318-321
We have developed a 920-MHz NMR system and performed the proton NMR measurement of H(2)O and ethylbenzene using the superconducting magnet operating at 21.6 T (920 MHz for proton), which is the highest field produced by a superconducting NMR magnet in the persistent mode. From the NMR measurements, it is verified that both homogeneity and stability of the magnet have a specification sufficient for a high resolution NMR. 相似文献
146.
Methoxyallene oxide was readily prepared in situ by epoxidation of methoxyallene with 3-chloroperbenzoic acid, and the subsequent reaction with aldehydes or acetals was promoted by titanium tetraiodide and additives to give 2,3-dialkoxy- or 3-hydroxy-2-methoxy ketones in good yields. 相似文献
147.
For high-precision frequency-based applications of lasers, the frequency difference between two independent lasers is accurately stabilized and maintained. We describe a simple and novel feed-forward method with an acousto-optic modulator. This method can be used in optical phase-locked loops. 相似文献
148.
T. Idehara I. Ogawa Y. Shimizu T. Tatsukawa 《International Journal of Infrared and Millimeter Waves》1998,19(6):803-816
Higher harmonic operation of gyrotrons is necessary to obtain high frequencies. Some gyrotrons included in the Gyrotron FU series developed at Fukui University have achieved operation at the third and even fourth harmonics of the electron cyclotron frequency. The output lies in the millimeter to submillimeter wavelength range and the output powers are several watts to several tens of watts. In this paper, the gyrotrons and the conditions under which they operate are described in detail. 相似文献
149.
T. Shimizu 《Physics letters. A》1979,71(4):319-322
A periodic solution, which the Lorenz equation has in the limit of high Rayleigh number r, is calculated up to the first order in by using the perturbation theory of nonlinear oscillations. 相似文献
150.
Various kinds of alcohols bearing phenylthio or phenylseleno moiety were converted into the corresponding carbonyl compounds in good to excellent yields by treating with dimesityl diselenide and -butyl hydroperoxide. 相似文献