Use of pulsed D2O laser for far-infrared EPR spectroscopy of DyPO4

EPR has been performed at 4.2°K on Dy³⁺ in DyPO₄ at 58.25 cm^-1, yielding g = 19.55 ± 0.16. The linearity of the Zeeman splitting indicates no perturbation from other levels, and in particular, that there are no levels between 58.25 cm^-1 and 23.0 cm^-1.     

[14α, 15α-3H] steroids for pharmacological research

It is shown in the present work that the labelling of steroids in ring D is suitable for the production of stable compounds. Two syntheses are described. The final products represent the tritium labelled forms of two pharmacologically important 4,9-dienones with high radiochemical purity. Unfortunately, these dienones are very sensitive to self-radiolysis. They must be stored as diluted solutions at low temperature.     

CO2-Laserinduzierte Isomerisierung von Methylisocyanid

Ohne Zusammenfassung     

Analyse asymptotique des équations de Transport dans le cas d’évolution

Nous démontrons la convergence de la solution d’une équation de Transport vers la solution d’une équation de Diffusion quand Je libre parcours moyen tend vers zéro, pour des équations d’évolution et un domaine borné dans deux cas: flux incident nul et réflexion spéculaire.     

Batching in single operation manufacturing systems

We introduce a new decision problem important to the efficient operation of resources in manufacturing systems. This problem of ‘batching’ is considered for single machine activities. It is shown that even for these simple models, lot splitting may occur and that these batching decisions may have a dramatic impact on the manufacturing lead time of items to be processed.     

The structure of amorphous and nanocrystalline W---Fe alloys prepared by high-energy ball milling

Tungsten powder (99.9% purity, 12 μm particle size) was milled in a hardened steel vial with six 440C stainless steel balls for 1–50 h. Because of the hardness of W, contamination and later alloying with Fe from abrasion of the stainless steel balls occurred. X-ray chemical analysis and weight-gain measurements of the milled powder indicated Fe contents varying from 3 at.% after 1 h to approximately 40 at.% after 50h milling. The powder pattern peaks of the nanocrystalline W were subjected to a Fourier analysis to determine the effective particle size and the microstrains within these particles. After 20 h milling, a particle size of 35 Å and microstrains of 0.5% were observed. The diffraction patterns from the W powder milled for 20 and 50 h were also analyzed in terms of the structure factor (interference function) and the atomic distribution function. The 20 h sample was predominantly nanocrystalline with a broad diffuse peak under the (110) and (211) reflections, while the 50 h sample was predominantly amorphous. After subtracting the remnant crystalline peaks, the position of the first peak in the reduced atomic distribution function, G_I(r), was found to be 2.7 Å.