A polarized atomic hydrogen beam

We describe the design and operating characteristics of a simple polarized atomic hydrogen beam particularly suitable for applications to crossed beams experiments. In addition to experimental measurements, we present the results of detailed computer models, using Monte-Carlo ray tracing techniques, optical analogs, and phase-space methods, that not only provide us with a confirmation of our measurement, but also allow us to characterize the density, polarization, and atomic fraction of the beam at all points along its path. As a subsidiary result, we also present measurements of the relative and absolute efficiencies of the V/G Supavac mass analyzer for masses 1 and 2.     

Quantum transport phenomena in disordered electron systems with spin–orbit coupling in two dimensions and below

Electron transport phenomena in disordered electron systems with spin–orbit coupling in two dimensions and below are studied numerically. The scaling hypothesis is checked by analyzing the scaling of the quasi-1D localization length. A logarithmic increase of the mean conductance is also confirmed. These support the theoretical prediction that the two-dimensional metal in systems with spin–orbit coupling has a perfect conductivity. Transport through a Sierpinski carpet is also reported.     

Application of displacement reactions in flame photometry-II Emission flame photometric determination of alkaline earth metals in the presence of interfering anions

For the emission flame photometric determination of strontium and barium in the presence of interfering ions such as phosphate, sulphate, arsenate and oxalate, calibration or simple standard addition methods cannot be used. Greatly reduced errors can be achieved by dividing the sample solution into four equal parts and adding to each certain known amounts of two metal ions. One of these is identical to the determinand (e.g., strontium or barium) the other has similar characteristics to it (e.g., calcium). The amounts of these metals are chosen so that the total (molar) concentration of these should be identical in all solutions, but the ratio of the concentrations of the two metals should be different. The emission of the determinand metal must be measured, and a standard addition plot produced. The amount of determinand present in the sample can be obtained from the intersection of the emission vs. concentration line with the concentration axis.     

Determination of calcium in the presence of interfering anions by flame photometry using an oxygen-enriched air-acetylene flame and a displacement method

Summary The interferences due to phosphate, oxalate, sulphate, arsenate, borate, nitrate and perchlorate in the flame photometric determination of calcium can be eliminated by the use of an oxygen-enriched airacetylene flame and the addition of excess sulphate to the sample. A method for the determination of calcium in the presence of these interferences is described and some results (1.0 and 0.5 mmole of Ca/l) are given.

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Flammenphotometrische Calciumbestimmung in Gegenwart störender Anionen mit Hilfe einer Sauerstoff-angereicherten Luft-Acetylen-Flamme und eines Verdrängungsverfahrens

Zusammenfassung Die Störungen durch Phosphat, Oxalat, Sulfat, Arsenat, Borat, Nitrat und Perchlorat konnten durch Verwendung einer Sauerstoff-angereicherten Luft-Acetylen-Flamme und durch Zusatz von überschüssigem Sulfat zur Probe verhindert werden. Eine entsprechende Methode wird beschrieben und einige Ergebnisse (1,0 und 0,5 mMol Ca/l) mitgeteilt.

     

The determination of cadmium by atomic absorption in air, water, sea water and urine with a R.F. carbon bed atomizer

The analytical parameters are described for the determination of cadmium by atomic absorption in air, water, sea water, and urine. The technique involves the use of an R.F. generator which heats up a carbon bed to approximately 1400°. This sample is reduced to free metal atoms and is analyzed directly afterwards. The atomization step and the measuring step are separate steps in this procedure. Detection limits of 10^-13 g were reached. Quantitative analyses were carried out on the types of samples indicated.     

Scaling law and critical exponent for α0 at the 3D Anderson transition

We use high‐precision, large system‐size wave function data to analyse the scaling properties of the multifractal spectra around the disorder‐induced three‐dimensional Anderson transition in order to extract the critical exponents of the transition. Using a previously suggested scaling law, we find that the critical exponent ν is significantly larger than suggested by previous results. We speculate that this discrepancy is due to the use of an oversimplified scaling relation.