Conformations of polymer chains in voids with an external electric field by Green's function methods

The statistical conformations of a length of polymer chain, such as DNA, trapped in a void within a gel under the influence of an external electric field, have been studied by the method of Green's functions. Based upon a rectangular box approximation for the void shape, the method gives an explicit analytical expression for the end-to-end distance (R_x) as a function of applied field strength, number of chain segments coiled within the void, and size of a chain segment. Results of calculations show that the field compresses the entrained coil into more compact configurations, as would be expected. Such compression is believed to affect the electrophoretic mobility of a long chain molecule like DNA in a dilute gel. © 1995 John Wiley & Sons, Inc.     

Search for non-strange baryonium states in the baryon exchange reaction K−p → Y0pp at 18.5 GeV/c

Narrow baryonium production in the baryon exchange reactions $\text{K}{}^{\mathrm{?}}\text{p}\text{→ Λ}\text{p}\text{p}$ and $\text{K}{}^{\mathrm{?}}\text{p}\text{→}\text{pK}{}^{\mathrm{?}}\text{p}\text{p}$ at 18.5 GeV/c is investigated in a 12 events/nb experiment performed at the CERN Ω′ spectrometer. No narrow structure is observed in the $\text{p}\text{p}$ mass spectra. Upper limits for production of baryonium states are given as a function of $\text{p}\text{p}$ mass.     

Lattice dynamics of simple superionic conductors

Using harmonic lattice dynamics we are able to calculate 1st order Raman results in the superionic conducting phases of AgI and CuI. We find that much of the calculated response is allowed because of the structural disorder that occurs in these materials. The evidence for the 1st order nature of the experimental results is given and the calculation is compared to experiment. It is also pointed out that Raman experiments (and calculations) can be performed on oriented single crystals of these disordered cubic materials yielding response that transforms as the A, E, and T irreducible representations of the cubic point groups.     

Applications of a slotted tube atom trap and flame atomic absorption spectrophotometry: Determination of antimony in copper based alloys

A sensitive system is described for the determination of antimony in copper-based alloys by flame atomic absorption spectrophotometry. The use of a slotted tube quartz atom trap improves precision and reduces the characteristic concentration by factors of 3 and 1.6 compared with the use of conventional flame AAS. Interferences are minimised by coating the internal surfaces of the STAT with copper.     

Determination of lead in copper based alloys using a modified quartz atom trap and flow injection flame atomic absorption spectrometry

Summary An improved system has been developed for the determination of lead in copper based alloys by flame atomic-absorption spectrophotometry. The system is based on flow injection coupled to flame-AAS with the STAT technique. The system improves the sensitivity and increases sample throughput compared to conventional flame-AAS; it also enhanced STAT working life times.

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Bestimmung von Blei in Kupferlegierungen mit Hilfe einer modifizierten Quarz-Atomfalle und der Fließinjections-Flammen-AAS

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One of us (N.C.) acknowledges financial support from Du Pont Science Grant 1987–1988 made to D.T.B.