Description: This note extends a certain combinatorics problem of I. Tomescu.

Description: This article discusses electron capture from K shells by fully stripped ions. Abstract: Cross sections for electron capture from inner shells by fully stripped ions are calculated and compared with data for K-shell vacancy production. A procedure for inclusion of the relativistic effect is developed, and the scheme of calculations is illustrated through sample evaluations of electron-capture cross sections.

Description: This article discusses mixed Grassmann manifolds. Abstract: Se construieşte varietea grassmanniană modelată intr-un spaţiu Banach mixt, situaţie ce generalizează simultan conceptele grassmanniene real şi complex.

Description: This article discusses M-shell x-ray-production cross sections in thin targets. Abstract: M-shell x-ray-production cross sections are reported for ₁¹H+ and ₂⁴He+ ions incident on thin targets of ₇₉Au, ₈₂Pb, ₈₃Bi, and ₉₂U. The energy of the ions ranged from 0.3 to 2.6 MeV in increments of 0.1 MeV. The first Born calculations overpredict the data at all energies studied. The perturbed-stationary-state calculations with energy loss, Coulomb deflection, and relativistic effects agree with the present data for both ₁¹H+ and ₂⁴He+ ions at ~0.35 MeV/u, overpredict the data at higher E₁/A₁, and underpredict the data at lower E₁/A₁. The electron-capture contribution to the target ionization is calculated to be less than 3.4% for the targets, projectiles, and energies reported in this work.

Description: This article discusses the thermal annealing behavior of an oxide layer under silicon. High resolution Rutherford backscattering spectrometry and ion channeling have been employed to evaluate the crystallinity of the surface silicon layer in oxygen implanted silicon. The quality of the top surface layer was determined by measuring the minimum yields along 〈110〉 directions in channeling spectra. Single crystal (100) silicon was implanted with 300 keV O2+ to a dose of 1.06 X 10(18) O2+/cm2. Measurements of residual damage of the top layer were made after annealing the samples at 1150 ˚C for times ranging from 10 to 240 min in either Ar or N2. Under the implantation conditions used in this experiment, a uniform oxide layer 0.52 μm thick was buried under a top silicon layer 0.17 μm thick. The buried oxide layer has abrupt silicon to oxide interfaces. The highest quality silicon surface layer was produced after 3-h annealing in an Ar ambient. A lesser quality silicon surface layer was produced by annealing for shorter times or for equivalent times in N2 ambient.