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71.
72.
Seiichi Miyanaga Hajime Yasuda Akio Hiwara Akira Nakumura Hiroshi Sakai 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(9-11):1347-1361
New types of air-stable metal-carbon composites which contain ultrafine metal particles (Fe, Co, Ni, Pd, Pt, Rh, Cu, etc.) uniformly dispersed in a carbon matrix were obtained by pyrolysis of a variety of soluble organometallic polymers, macromolecular-metal complexes, and blends of coal pitch with metal complexes at 400-1400°C in N2. Some of their unique physical properties and functions are noted. 相似文献
73.
This paper proposes the use of a formal grammar for the verification of mathematical formulae for a practical mathematical
OCR system. Like a C compiler detecting syntax errors in a source file, we want to have a verification mechanism to find errors
in the output of mathematical OCR. A linear monadic context-free tree grammar (LM-CFTG) is employed as a formal framework
to define “well-formed” mathematical formulae. A cubic time parsing algorithm for LM-CFTGs is presented. For the purpose of
practical evaluation, a verification system for mathematical OCR is developed, and the effectiveness of the system is demonstrated
by using the ground-truthed mathematical document database InftyCDB-1 and a misrecognition database newly constructed for
this study. 相似文献
74.
75.
76.
Takaishi T Sagawa A Nagakura K Maeda T 《The Journal of the Acoustical Society of America》2002,111(6):2601-2608
As the maximum speed of high speed trains increases, the effect of aeroacoustic noise on the sound level on the ground becomes increasingly important. In this paper, the distribution of dipole sound sources at the bogie section of high speed trains is predicted numerically. The three-dimensional unsteady flow around a train is solved by the large eddy simulation technique. The time history of vortices shows that unstable shear layer separation at the leading edge of the bogie section sheds vortices periodically. These vortices travel downstream while growing to finally impinge upon the trailing edge of the section. The wavelength of sound produced by these vortices is large compared to the representative length of the bogie section, so that the source region can be regarded as acoustically compact. Thus a compact Green's function adapted to the shape can be used to determine the sound. By coupling the instantaneous flow properties with the compact Green's function, the distribution of dipole sources is obtained. The results reveal a strong dipole source at the trailing edge of the bogie section where the shape changes greatly and the variation of flow with time is also great. On the other hand, the bottom of the bogie section where the shape does not change, or the leading edge and boundary layer where the variation of flow with time is small, cannot generate a strong dipole source. 相似文献
77.
90 degrees phase-matched third-harmonic generation of CO(2) laser frequencies in AgGa(1-x)In(x)Se(2)
AgGa(1-x) In(x)Se(2) with x=0.474 was found to be 90 degrees phase matchable for third-harmonic generation of CO(2) laser wavelengths 9.2714-10.5910 mum by means of temperature tuning. Sellmeier equations and the thermo-optic constant for this crystal are presented. 相似文献
78.
Masahiro Ueda Sanae Mizuno Akio Matsumura Fumio Tohjyo 《Optics and Lasers in Engineering》1996,24(4):339-350
An optical method for measuring the thickness of heterogeneous materials has been studied. The method is based on the light attenuation theory. A complete system has been constructed in order to demonstrate the applicability of the present method for industrial use. The experimental set-up consists of semiconductor lasers, focusing lenses, photo-diodes serving as a power meter and a personal computer with an A/D converter for data acquisition. Averaging of numerous measurements is required in the present method because the heterogeneous cell structure of the foam material yields large fluctuations in transmitted light levels. The fluctuations can be reduced to below 1% of the transmitted light power by 80 times averaging. The error of the measurement is considered to be a few tens of micrometers in thickness. The present system is capable of sampling data at a rate of 400 Hz and has been successfully applied to a manufacturing process. 相似文献
79.
We revisit the EPR problem and make clear what is a correct comprehension of its problem. When one applies the quantum mechanics correctly, it will be shown that there is no paradox. According to these lines of thought, a quantum teleportation scheme without resort to the von Neumann projection postulate is presented. 相似文献
80.
The Shubnikov-de Haas like oscillation and rapid increase of the carrier concentration above the quantum limit magnetic field (H0) are observed in Pb1?xSnxTe doped with indium (x=0.33 and 0.35). Experimental results can be reproduced satisfactorily by the calculation based on the Fermi level pinning model due to In-impurities, where we take into account the level broadening (Г) effect of the band structure. It is confirmed that the increasing rate of carrier concentration with respect to magnetic field above H0 decreases with larger Г. 相似文献