Dynamic two-frequency interferometry for small displacement measurements

Two-frequency interferometry for small displacement measurements is examined from a practical point of view. A laser beam that is modulated sinusoidally in intensity by an acousto-optic Bragg cell provides signal and reference optical waves to produce dynamic interference. The output signal of a photodetector receiving the interference is composed of optical homodyne and heterodyne components. The heterodyne component carries a vibrational displacement to be detected on its amplitude. A sinusoidal vibration amplitude is measured down to 0.5 nm.     

IR study on the intensity of ν1 of carbon disulfide

The IR intensity of ν₁ of carbon disulfide is reported in various states. The intensity increases with a decrease in temperature. Less than 10% of the observed intensity can be explained in terms of an electric field applied from an adjacent molecule. On the other hand, nearly half of the intensity is explained in terms of a vibrational coupling of ν₁ with ν₃ or ν₂, which is estimated from dimer models, on the assumption that the observed IR and Raman frequencies can be attributed to dimers.     

Acoustic parameter measurements by acousto-optic diffraction techniques using a light-beam of one acoustic wavelength width

A method is presented for measuring the Raman-Nath parameter by an acoustically diffracted light-beam of one acoustic wavelength width. The diffraction spectrum obtained is not discrete but broadened continuously because of the width of the light-beam itself. The Raman-Nath parameter can be determined from the intensity measurement at the centre of the diffraction pattern. The acoustic wavelength can also be determined by measuring the light-beam width of one acoustic wavelength at which a beating photocurrent, produced by the positive and negative first-order diffraction components, dies out at the centre of the pattern.     

Facile isolation ofEndo-pectate lyase fromErwinia carotovora based on electrostatic interaction

Endo-pectate lyase (PATE) from Erwinia carotovora was selectively cosedimented with extracellularly produced lipopolysaccharide-lipid complex (LPSLC) through dialysis of the cell free culture broth. The selective isolation of PATE was confirmed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The cosedimentation of the PATE with LPSLC was initiated by decreasing conductivity of the solution and terminated at approx 1 m siemens (mScm-1). As much as 62% of PATE activity in the culture broth was removed by precipitation. PATE was isolated from the precipitate by gel chromatography. The cosedimentation of PATE with LPSLC was remarkably affected by pH or ionic strength. The addition of polycationic peptide polymyxin B sulfate or a metal chloride affected the interaction. The cosedimentation was diminished by acetylation of the free amino groups of PATE. From these results, it was confirmed that the cosedimentation was induced by electrostatic interaction.     

Scattering of potassium atomic beams from various cleaved surfaces

Scattering of potassium atomic beams from cleaved surfaces of LiF, KCl and mica were studied. The observed spatial distributions follow the cosine distribution in most cases. At large incident angles the distributions from LiF and KCl deviate from the cosine and show apparent backscatterings. A simple model is proposed to interpret the backscattering in terms of macroscopic roughness of cleaved surfaces. The sticking coefficient S (t) is defined and the mass balance between the incident and outgoing atoms is examined. Mass balance holds within the limits of errors on the surfaces of LiF and KCl at temperatures above 400 K. On a mica surface deposition of potassium atoms is observed even at temperatures higher than room temperature. It is shown from the change of the sticking coefficient that the deposition does not proceed linearly in the initial period.     

Determination of optical constants and thickness of passivating films on nickel from multiple-angle-of-incidence reflectivity measurements

A method is proposed which allows to determine without non-optical assumptions the complex refractive index and the thickness of thin surface films from measurements of the relative changes of reflectivity due to the formation or removal of the film at different angles of incidence with monochromatic light polarized perpendicular or parallel to the plane of incidence. The exact equations for the reflectivity change are used, since the linear approximation introduces systematic errors which are too large in view of the experimental accuracy. The method is applied to the passivating film formed on nickel in 1 M sulphuric acid after 1 h at U_HSS=0.85 V. A complex refractive index n₂=2.10 (±0.05)–0.46 (±0.02) i and a film thickness d=2.1 (±0.1) nm were found. In the spectrum of the optical constants in the range 1.4≤hv/e V≤4.8 a characteristic peak of the absorption coefficient was observed at 3.1 e V. Both the values at γ=500 nm and the spectra of the optical constants are explained by a partly hydrated nickel oxide film.     

Structure of anislactone A; a new skeletal type of sesquiterpene from the pericarps of Illicium anisatum

A novel sesquiterpene lactone was isolated from the pericarps of Illicium anisatum, a well known toxic plant in Japan, and its structure was established from spectral data and X-ray crystallographic analysis.