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Mizukoshi Y Tsuru Y Tominaga A Seino S Masahashi N Tanabe S Yamamoto TA 《Ultrasonics sonochemistry》2008,15(5):875-880
Aqueous sample solutions containing noble metal ions (HAuCl4, Na2PdCl4, H2PtCl6), polyethyleneglycol monostearate, and magnetic maghemite nanoparticles were irradiated with high power ultrasound. Analyses of the products showed that noble metal ions were reduced by the effects of ultrasound, and the formed noble metal nanoparticles were uniformly immobilized on the surface of the maghemite. The present “one pot process” significantly simplifies the immobilization of noble metal nanoparticles on the surface of supports, compared with the conventional impregnation method. The average diameter of immobilized Au was 7–13 nm, and the diameters of Pd and Pt were several nm. The diameters depended upon the concentration of polyethyleneglycol monostearate and the concentration of noble metal ions, but not upon the maghemite concentration, indicating the possibility of the morphological controls of the products by adjusting these preparation conditions. The measurements of the average diameters and the numbers of immobilized Au nanoparticles obtained under various conditions suggest that the nucleation of Au does not occur on the surface of maghemite, but it might occur in the homogeneous bulk solution. 相似文献
105.
Plasmonics in the UV region has been widely focused because of the higher energy and the abundant electronic resonances compared to the conventional visible plasmonics. Recently, we have investigated the surface plasmon resonance (SPR) properties of the Al film, aiming for the application as refractive index sensors. Utilizing the UV lights, we expect three advantages: high sensitivity, material selectivity, and surface selectivity. By using an original attenuated total reflectance spectroscopic instrument, Al‐SPR angle and wavelength were investigated with changing environments on the Al film. Al film thickness and materials of prisms on which Al was evaporated were also important factors for the SPR properties. By optimizing the conditions, the Al film worked as a sensor both in air and in liquids. In addition, our established system expands the plasmonics into an even higher energy region than 200 nm, while the UV‐plasmonics have been studied in the wavelength region longer than 200 nm. 相似文献
106.
Aubert B Bona M Boutigny D Karyotakis Y Lees JP Poireau V Prudent X Tisserand V Zghiche A Tico JG Grauges E Lopez L Palano A Pappagallo M Eigen G Stugu B Sun L Abrams GS Battaglia M Brown DN Button-Shafer J Cahn RN Groysman Y Jacobsen RG Kadyk JA Kerth LT Kolomensky YG Kukartsev G Pegna DL Lynch G Mir LM Orimoto TJ Osipenkov IL Ronan MT Tackmann K Tanabe T Wenzel WA Del Amo Sanchez P Hawkes CM Watson AT Koch H Schroeder T Walker D Asgeirsson DJ Cuhadar-Donszelmann T Fulsom BG Hearty C 《Physical review letters》2008,100(2):021801
We present measurements of the semileptonic decays B--->D0tau-nutau, B--->D*0tau-nutau, B0-->D+tau-nutau, and B0-->D*+tau-nutau, which are potentially sensitive to non-standard model amplitudes. The data sample comprises 232x10(6) Upsilon(4S)-->BB decays collected with the BABAR detector. From a combined fit to B- and B0 channels, we obtain the branching fractions B(B-->Dtau-nutau)=(0.86+/-0.24+/-0.11+/-0.06)% and B(B-->D*tau-nutau)=(1.62+/-0.31+/-0.10+/-0.05)% (normalized for the B0), where the uncertainties are statistical, systematic, and normalization-mode-related. 相似文献
107.
Quantitative analysis of optical power budget of bismuth oxide-based erbium-doped fiber 总被引:1,自引:0,他引:1
We investigated optical power budget of Bi2O3-based erbium-doped fiber (BIEDF). Lateral spontaneous emissions and scattering laser powers in the BIEDF were measured quantitatively by using an integrating sphere. Compared with the power of amplified spontaneous emission and signal detected at the output fiber end, it was found that considerable powers were consumed by the laterally emitting lights. As an optically undetected loss limits power conversion efficiency (PCE) of the fiber amplifier, the effect of nonradiative decay from the termination level of pump excited state absorption (pump ESA) was estimated from decay rate analyses of the relevant levels. The nonradiative loss was comparable to amplified signal power in the BIEDF when pumped with a 980-nm LD. Nonradiative decay following cooperative upconversion (CUP) process is also discussed using rate equations analysis. 相似文献
108.
Y. Tanabe T. Adachi H. Sato T. Sasaki Y. Koike 《Journal of Physics and Chemistry of Solids》2008,69(12):3217-3220
We have measured the temperature dependence of the magnetic susceptibility, χ vs. T, and the magnetization curve, M vs. H, for NbSe2 single crystals, in order to compare the superconducting (SC) state in the overdoped regime of La2−xSrxCuO4 (LSCO) with the SC state of the layered conventional superconductor NbSe2. While a plateau in χ vs. T in a moderate magnetic field and a so-called second peak in M vs. H, which is due to the marked enhancement of vortex pinning, have been observed in the overdoped regime of LSCO, these behaviors have not been observed in NbSe2. The present results indicate that the anomalously marked enhancement of vortex pinning is a characteristic feature in the overdoped LSCO where a microscopic phase separation into SC and normal-state regions takes place. 相似文献
109.
Jun-ichi Nishizawa Tetsuo Sasaki Ken Suto Masahiko Ito Takashi Yoshida Tadao Tanabe 《International Journal of Infrared and Millimeter Waves》2008,29(3):291-297
We developed high-resolution GaP THz signal generator using Cr:Forsterite lasers with gratings as both a pump and a signal
beam for difference-frequency generation. A line width of less than 500 MHz and a wide tunable frequency range (0.6–6.2 THz)
provide sufficient resolution for measuring materials with sharp absorption bands using the generator as the light source
for a THz spectrometer. This is suitable for materials such as gases or solid samples at low temperatures. We demonstrated
the detection of defects in organic materials, as they appear as slight deviations in the absorption frequency in the THz
region. 相似文献
110.