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31.
Coussement R Rostovtsev Y Odeurs J Neyens G Muramatsu H Gheysen S Callens R Vyvey K Kozyreff G Mandel P Shakhmuratov R Kocharovskaya O 《Physical review letters》2002,89(10):107601
A significant reduction of absorption for single gamma photons has been experimentally observed by studying M?ssbauer spectra of 57Fe in a FeCO3 crystal. The experimental results have been explained in terms of a quantum interference effect involving nuclear level anticrossing due to the presence of a combined magnetic dipole and electric quadrupole interaction. 相似文献
32.
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
33.
34.
Matsuyama Kiyoshi Mishima Kenji Hayashi Ken-ichiro Matsuyama Hideto 《Journal of nanoparticle research》2003,5(1-2):87-95
A novel preparation method is reported for the microencapsulation of TiO2 nanoparticles by rapid expansion of supercritical solution with a nonsolvent. A suspension of TiO2 nanoparticles in carbon dioxide containing a cosolvent and dissolved polymer is sprayed through a nozzle to atmospheric pressure. After rapid expansion, polymer microspheres were obtained. The microspheres do not tend to agglomerate, since the pure cosolvent is a nonsolvent for the polymer. The structure and morphology of microspheres were investigated by SEM, TEM and XRD. The obtained polymer microspheres are microcapsules of TiO2 nanoparticles. The mean particle diameter and particle size distribution of microcapsules, could be controlled by changing the polymer concentration, pre-expansion pressure, temperature and injection distance. The polymer feed compositions are more effective than other factors on the control of particle size. 相似文献
35.
Kyozo Kanamoto Sheng Lan Naoki Ikeda Yoshimasa Sugimoto Kiyoshi Asakawa Hiroshi Ishikawa 《光学学报》2003,23(Z1)
Single photonic crystal defects based on an air-bridge structure were fabricated. We obtained sharp defect modes with quality factors higher than 600 and observed their response to ultrashort optical pulses by utilizing two-photon absorption. 相似文献
36.
He Q Muramatsu H Park CS Thorndike EH Coan TE Gao YS Liu F Artuso M Boulahouache C Blusk S Butt J Dorjkhaidav O Li J Menaa N Mountain R Nandakumar R Randrianarivony K Redjimi R Sia R Skwarnicki T Stone S Wang JC Zhang K Csorna SE Bonvicini G Cinabro D Dubrovin M Briere RA Chen GP Chen J Ferguson T Tatishvili G Vogel H Watkins ME Rosner JL Adam NE Alexander JP Berkelman K Cassel DG Crede V Duboscq JE Ecklund KM Ehrlich R Fields L Galik RS Gibbons L Gittelman B Gray R Gray SW Hartill DL 《Physical review letters》2005,95(22):221802
Using 0.8 x 10(6) D+ D- pairs collected with the CLEO-c detector at the psi(3770) resonance, we have searched for flavor-changing neutral current and lepton-number-violating decays of D+ mesons to final states with dielectrons. We find no indication of either, obtaining 90% confidence level upper limits of B(D+ --> pi+ e+ e-) < 7.4 x 10(-6), B(D+ --> pi- e+ d+) < 3.6 x 10(-6), B(D+ --> K+ e+ e-) < 6.2 x 10(-6), and B(D+ --> K- e+ e+) < 4.5 x 10(-6). 相似文献
37.
Shunsuke Suzuki Akira Nakajima Munetoshi Sakai Naoya Yoshida Yoshikazu Kameshima Kiyoshi Okada 《Surface science》2006,600(10):2214-2219
Both fluoroalkylsilane (FAS) and octadecyltrimethoxysilane (ODS) were coated on oxidized silicon wafers using soaking and CVD method. Smooth coatings with Ra values of less than 1 nm were attained. The slope of the sliding acceleration against the inverse of the droplet mass showed an inflection point. That point shifted to the direction of smaller droplets with decreasing FAS ratio to ODS. The water droplets’ length was increased when the sliding velocity was increased. Fluoroalkylsilane addition to ODS increases the interaction between water and the hydrophobic surface. Results showed that the sliding acceleration of a water droplet depends strongly on the surface ratio of these silanes. 相似文献
38.
Takemoto H Honda K Masaki S Shimada Y Fujimoto I 《The Journal of the Acoustical Society of America》2006,119(2):1037-1049
A 3D cine-MRI technique was developed based on a synchronized sampling method [Masaki et al., J. Acoust. Soc. Jpn. E 20, 375-379 (1999)] to measure the temporal changes in the vocal tract area function during a short utterance /aiueo/ in Japanese. A time series of head-neck volumes was obtained after 640 repetitions of the utterance produced by a male speaker, from which area functions were extracted frame-by-frame. A region-based analysis showed that the volumes of the front and back cavities tend to change reciprocally and that the areas near the larynx and posterior edge of the hard palate were almost constant throughout the utterance. The lower four formants were calculated from all the area functions and compared with those of natural speech sounds. The mean absolute percent error between calculated and measured formants among all the frames was 4.5%. The comparison of vocal tract shapes for the five vowels with those from the static MRI method suggested a problem of MRI observation of the vocal tract: data from static MRI tend to result in a deviation from natural vocal tract geometry because of the gravity effect. 相似文献
39.
We study reflection diffuse optical tomography using two-dimensional (2D) continuous-wave source-detector arrays on the surface
of semi-infinite medium, aiming at imaging the perfusion and the hemoglobin oxygen saturation variation of human cerebral
cortex with brain activation. We had previously formulated the inverse problem with Moore-Penrose inversion. When we use simple
regularization in this inverse problem, the reconstruction sensitivity decreases markedly with the depth so that the signal
in the deep range may be masked by an unwanted signal in the shallow range. In this paper, we propose a depth-adaptive regularized
reconstruction, in which we assign a smaller regularization parameter with the depth. We demonstrate improvement of the three-dimensional
(3D) reconstruction uniformity using the proposed scheme. 相似文献
40.
A fabrication of all-solid-state thin-film rechargeable lithium ion batteries by sol-gel method is expected to achieve both the simplification and cost reduction for fabrication process. TiO2 thin film electrode was prepared by PVP (polyvinylpyrrolidone) sol-gel method combined with spin-coating on Li1 + xAlxGe2 − x(PO4)3 (LAGP) solid electrolyte which has wide electrochemical window. The thin film was composed of anatase TiO2 that is the most active phase for Li insertion and extraction and contacted well with LAGP substrate. In the cyclic voltammogram, a redox couple was observed at 1.8 V vs. Li/Li+ assigned to Li insertion/extraction into/from anatase TiO2, indicating that the thin film worked as electrode for lithium battery. The charge and discharge test in various charge and discharge rates revealed that the discharge process (delithiation) is thought to be faster than charge process (lithiation). It is attested that the sol-gel process, which derives both simplification and cost reduction for fabrication process, can be applied to thin film battery using LAGP solid electrolyte. 相似文献