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81.
82.
The frequency of the 3.39 μm He-Ne laser was locked to the CH4 saturated absorption line by means of integral-proportional feedback control, i.e., dual feedback control. The frequency modulation was applied by a vibrating mirror placed outside a laser cavity, obtaining a modulation-free laser beam with a stabilized frequency. The long-term stability achieved under integral feedback control was aboutpm1.1 times 10^{-11} , which was further improved topm1.35 times 10^{-12} under dual feedback control. The Allan variance measured by the photomixing technique was1.77 times 10^{-12} at an averaging time 100 s. 相似文献
83.
84.
Two kinds of the homogeneous nucleation theory exist at the present: the classical nucleation theory and the semiphenomenological model. To test them, we performed molecular-dynamics (MD) simulations of nucleation from vapor to liquid with 5000-20,000 Lennard-Jones-type molecules. Simulations were done for various values of supersaturation ratios (from 2 to 10) and temperatures (from 80 to 120 K). We compared the size distribution of clusters in MD simulations with those in the theoretical models because the number density of critical clusters governs the nucleation rate. We found that the semiphenomenological model achieves excellent agreements in size distributions of the clusters with all MD simulations we done. The classical theory underestimates the number density of the clusters in the temperature range of 80-100 K, but overestimates in 100-120 K. The semiphenomenological model also predicts well the nucleation rate in MD simulations, while the classical nucleation theory does not. Our results confirmed the validity of the semiphenomenological model for Lennard-Jones-type molecules. 相似文献
85.
The formation of 1-substituted-3-hydroxy-1H-indazole and 1-substituted-benzimidazolin-2-one derivatives by thermal reaction of N-substituted-N-arylcarbamoyl azides was examined. 相似文献
86.
The surface composition and electronic structure of carburized tungsten trioxide, which is prepared by heating WO3 in carbon monoxide atmosphere at 700°C, are investigated using X-ray photoelectron spectroscopy (XPS). The relationship between the surface composition and the catalytic activity for methanol electro-oxidation is clarified. The formation of tungsten carbide at the surface enhances the catalytic activity. On the other hand, the presence of free carbon or tungsten trioxide in the surface layer reduces the activity remarkably. It is also shown that, the higher the electronic density of states near the Fermi level, the higher the catalytic activity. Additionally, the catalytic behavior of tungsten carbide for methanol electro-oxidation is mentioned. 相似文献
87.
V. P. Guinn J. Leslie L. Nakazawa 《Journal of Radioanalytical and Nuclear Chemistry》1982,70(1-2):513-525
This paper describes further development and experimental testing of the INAA Advance Prediction Computer Program (APCP).
Copies of the APCP written in BASIC-PLUS are finally ready for distribution. Experimental tests with four reference materials
are described. The program is extremely useful as a quide to optimum conditions, sample sizes, elements detectable, and INAA
lower limits, of detection for any sample matrix of only approximately known major and minor elemental composition. Additional
developments in progress are mentioned. 相似文献
88.
In this paper, we present the validity of in-line-type differential push-pull methods using segmented gratings with respect
to the radial shift of an objective lens by numerical calculation for the first time. In these differential push-pull methods,
the segmented gratings for generating sub spots are divided into two to four regions each with a specific phase value and
a width. Tracking error signals are calculated with respect to the objective lens shift under parameter conditions of the
widths of the segmented regions. The obtained results show that the grating of the simpler configuration with two regions
reveals good compatibility between DVD-R and DVD-RAM compared with those with three or four regions 相似文献
89.
Uchida H Song JM Suzuki S Nakazawa E Baba N Watanabe M 《The journal of physical chemistry. B》2006,110(27):13319-13321
To confirm the superiority of newly developed electrocatalyst layer (ECL) for polymer electrolyte fuel cells, three-dimensional dispersion states of Nafion ionomer in Pt/carbon black agglomerates were analyzed by electron tomography based on multiple TEM images taken at different tilt angles. Uniform distribution of the ionomer has been first observed, proving the high catalyst utilization in the new ECL distinctive from that of the conventional one. 相似文献
90.
[reaction: see text] The highly stereoselective construction of the C3 stereogenic center of the taxol C-ring is described. The trans isomer at the C3-C8 position of the taxol C-ring, which is required for the total synthesis, as well as its diastereomeric cis isomer were successfully synthesized with highly diastereoselective S(N)2' reduction of the allylic phosphonium salts. 相似文献