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Volume 30, Issue 8
Displaying 1-3 of 3 articles from this issue
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Fumio NAGATA, Hiroshi KAKIBAYASHI1987 Volume 30 Issue 8 Pages 645-651
Published: August 20, 1987
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSDownload PDF (1649K) -
Makoto SAKURAI, Tatsuo OKANO, Yutaka TUZI1987 Volume 30 Issue 8 Pages 652-657
Published: August 20, 1987
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSSystem for the study of high-resolution electron energy-loss spectroscopy (EELS) on condensed molecules was constructed. Incident electron energy of the spectrometer is variable in the range of 1-30 eV. Condensed layer of CO2 was formed on a clean Ag (111) surface which was cooled to 40 K using a closed cycle refrigerator. Energy loss peaks were observed at 84, 168, and 291 meV, which are assigned to a bending mode, a symmetric stretch mode and an asymmetric stretch mode of CO2, respectively. A few combinational modes were also observed for the exposures larger than 0.5 L. Incident electron energy dependence of vibrational excitation cross-section for the symmetric stretch mode exhibited resonant effect at 9 eV. Incident angle dependence of the cross-section for dipole active modes showed exponential decay as the scattering condition deviated from specular geometry, while the incident angle dependence for the symmetric stretch mode was poor.View full abstractDownload PDF (776K) -
Gen'ichi HORIKOSHI1987 Volume 30 Issue 8 Pages 658-665
Published: August 20, 1987
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSThe old problem on the molecular flow conductance in a long conduit pipe with a uniform cross sections was analyzed by using a concept of gas diffusion process in a uniform medium. This problem was first treated by Knudsen giving a famous approximate expression for the molecular flow conductance and, after a year, Smoluchowski has given a rigorous expression by summing up motions of individual molecules. In this report, a trial was made to understand molecular flow in a conduit pipe as one of the diffusion processes. It turned out that the well known expression of diffusion coefficient (D=1/3·υλ) did not apply to the problem. A careful consideration has given a more rigorous expression of diffusion coefficient, i.e.
D=1/2·υ (l cos θ) 2/lwhere l and l2 are the average and average square of free paths of gas molecules and θ is the angle between l and molecular density gradient. By using the above expression, one can treat the molecular flow as an diffusion process and can obtain the regorous expression of molecular flow conductance.View full abstractDownload PDF (856K)
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