A diglyceride uronoside from streptomyces LA 7017

Summary A new glycolipid, a 1-O-[4-O-(-D-glucopyranosyl)--D-glucopyranuronosyl]-2,3-diglyceride has been isolated from the total cell lipids of Streptomyces LA 7017.Institute of the Chemistry of Natural Compounds, Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 664–671, November–December, 1970.     

Impedance and photoadmittance of a passive iron electrode in alkaline sodium sulfide solutions

The intensity-modulated photocurrents (photoadmittance) and the electrochemical impedance of an anodically oxidized iron electrode are studied in alkaline solutions containing the sulfide ion. The photooxidation of S^2- proceeds via a stage of their adsorption. The concentration of S^2- adsorbed on the surface decreases at a potential shift in the positive direction     

Effect of thermobaric conditions in a uniform bed on the displacement of low-viscosity oil by supercritical carbon dioxide

An experimental setup was constructed that makes it possible to study oil displacement over wide pressure (up to 20 MPa) and temperature (up to 373 K) ranges under conditions reproducing the thermobaric, geological, and physicochemical conditions in real oil beds, as well as the parameters of displacing agents. Experiments on the displacement of kerosene from a model oil bed with supercritical carbon dioxide at temperatures of 313–353 K and pressures within 7–12 MPa were performed. The results are indicative of a high efficiency of recovery of low-viscosity oils with supercritical carbon dioxide.     

Observation of the pre-explosion state and of the initial moment of an explosion of a field emission center in a field emission microscope

Never-before-observed emission images corresponding to a transition from intense field emission to explosive electron emission are obtained in a Muller field emission microscope with short (∼2 ns)high-voltage pulses. These images are much brighter than ordinary field emission images. Moreover, the images have a characteristic multi-brightness structure with ring-shaped frames around regions of different brightness. Analysis of the experimental data points to a field emission nature of these images. The appearance of such emission images can be explained by emission from a liquid phase which arises immediately prior to the explosion of a microemitter. Pis’ma Zh. éksp. Teor. Fiz. 67, No. 4, 280–285 (25 February 1998)     

Impedance and Photoadmittance of Passive Iron Electrodes in Different Solutions

Electric characteristics of the oxide film at the surface of an anodized iron electrode in 0.5 M Na₂SO₄, NaNO₃, and Na₂MoO₄ solutions are studied using the impedance and photoadmittance measurements and taking polarization curves. The impedance frequency spectra correspond to an equivalent circuit comprising two parallel (RC) chains connected in a series. The relaxation time of the high-frequency circuit approaches that of the photopotential; hence, it can be related to the impedance of the oxide film. The low-frequency component of the impedance describes the impedance of the film/solution interface. In the Na₂SO₄ solution, the oxide film resistance is significantly higher and the capacitance is lower than in two other solutions, which can be explained by the film thickening. The marked concurrent decrease in the resistance and increase in the capacitance of the film/solution interface at 1.2 V in all solutions is caused by oxygen adsorption, which precedes oxygen evolution.     

Influence of a Non-Stationary Magnetic Field on the Charge Composition and Energy Distribution of Ions of the Cathode Plasma of a Vacuum Arc

Russian Physics Journal - The influence of an external non-stationary axial magnetic field on the charge composition and energy distribution of ions of various charge states in the cathode plasma...