Stripping Extraction Research Articles

Specimen transfer from the electrolyte to the UHV in a closed system and some examinations of the double layer on Cu

A transfer system is described which permits the electrochemical preparation of specimens in a purified argon atmosphere and their transport into the UHV for surface analysis. This transfer prevents contamination and oxide formation on semi-noble metals. Reactive metals from only a few monolayers of oxide. This permits examination of electrochemically prepared metal surfaces, which is otherwise not possible. For hydrophobic copper surfaces, the composition of the electrical double layer may be studied. The extraction of the electrode strips the electrolyte off in the vicinity of the Helmholtz layer. For NaClO 4 solutions, the amount of Na + ions and the excess charge decrease linearly with the electrode potential in agreement with a constant electrode capacity. The formation of a prepassive and passive layer leads to a pronounced increase of adsorbed Na + ions. For Cs 2SO 4, specific and co-adsorption of both ions is observed with a minimum in the region of the potential of zero charge.

Beam Dynamics of RF Devices to Improve the Efficiency of Proposed H- Extraction from TRIUMF

Future developments at TRIUMF would benefit from the direct extraction of H- ions in addition to the present stripping extraction of protons. The radial beam density at the first extractor septum must be reduced to achieve 90% extraction efficiency of a 100 μA, 450 MeV beam. Two methods have been considered. Installation of RF booster cavities could triple the energy gain/turn at the septum radius. Alternatively a radial RF field at νr= 3/2 could generate a coherent betatron oscillation. The subsequent precession could produce local density minima 20% of the average. The beam dynamics for both methods have been investigated using a simple analytic model and a general orbit code. The booster cavities introduce phase-dependent radial and vertical forces (the former leading to phase compression) that may render the motion of some phases unstable. Large coherent oscillations may be unstable near the resonance. Operating tolerances are specified and successful test results of the second scheme are presented.

Microspectrophotometric analysis of the location of ] avenalumin accumulation in oat leaves in response to fungal infection

Cellular localization of avenalumins accumulated in oat leaves infected by either crown rust through stomata or rice blast fungus through the cuticular layer was demonstrated by microspectrophotometry using the fluorescence emission and u.v. absorption spectra characteristic of avenalumins. Thin sections of incompatible rust-infected leaves revealed collapsed mesophyll cells which emitted autofluorescence and absorbed u.v. light with spectral characteristics close to those of the avenalumins. Autofluorescent and u.v.-absorbing cells were detected only in incompatible rust race-oat combinations. Epidermal cells accumulated quite high levels of avenalumins in response to cuticular infection by the facultative pathogen. Spectrophotometry of the freshly stripped epidermis showed the presence of autofluorescent materials, with spectra characteristic of avenalumins, in infected and the directly adjacent cells. U.v.-absorption spectra close to those of avenalumins were also detected in fluorescent cells. Extraction of epidermal strips with methanol reduced fluorescence emission and u.v.-absorption in fluorescent cells by c. 40% of the original, thus suggesting that avenalumins could be partially eluted out of the fluorescent cells. Epidermal cells which were injected with aqueous solution of avenalumin I became fluorescent. Results suggest that avenalumins accumulate in the fluorescent mesophyll and epidermal cells formed in oat leaves at infection sites of fungal pathogens.

Calcium in smooth muscle from the opossum esophagus.

SummaryTransverse muscle strips were cut from four segments of the opossum esophagus. Segment I was the segment of smooth muscle bordering on the striated muscle proximally and Segment IV was the distal segment which includes the lower esophageal sphincter. Segments II and III were the two central fourths of the smooth muscle esophagus. The tissue calcium content was determined in strips coming from the four segments after ashing and extraction of strips in concentrated HCl-HNO3. The calcium content (in mmole/kg wet muscle ± 1 SE) was 2.70 ± 0.1 in Segment I, 2.8 ± 0.3 in Segment II, 2.6 ± 0.3 in Segment III, and 2.6 ± 0.3 in Segment IV after 2 hr of incubation.After incubation of strips coming from the four segments, efflux of 45Ca was measured during 15 two-min periods. Efflux was rapid at first with a halftime of 5 min and slowed after three periods to a halftime of 29 min. In all nine animals tested, efflux from the lower esophageal sphincter was slower than that from muscle of the esophageal body. Th...

Roof displacement in working thick steeply dipping seams in the Kuzbass to the rise with stowing of the worked-out area

The main group of mining systems for thick steeply dipping coal seams with stowage of the worked-out area, adopted recently in industrial trials in pits in the Kuznetsk coalfield, involves advance of the extraction front to the rise of the seam by means of successive mechanized extraction of narrow strips to the strike. This group of new systems has many features that are almost identical with those used for some time in pits in this coalfield in systems of mining with laterally inclined and sloping panels with hydraulic stowing. Thus the data, resulting from an investigation of the development of roof displacements during extraction of a single laterally inclined panel or of all the panels worked up to the time of scheduled advance of the extraction front, can be used to predict rock pressure phenomena in similar new technological schemes.