Modeling the drift properties of gas mixtures of a GasPixel detector for upgrading the ATLAS setup

The results of modeling the drift properties of gas mixtures for a GasPixel detector that would provide highly accurate track data at high luminosity values in the inner detector of the ATLAS setup at the Super LHC collider are presented.     

The best trigonometric approximations and the Kolmogorov diameters of the Besov classes of functions of many variables

The order estimates for the best trigonometric approximations and the Kolmogorov diameters of the classesB _p, ^r of functions of many variables in the spaceL _q are obtained for certain values of the parametersp andq.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 45, No. 5, pp. 663–675, May, 1993.     

A new synthesis of the pheromone of the codling moth — Dodeca-8E,10E-dien-1-ol — Via an enynic intermediate

A new method has been developed for the synthesis of the main component of the pheromone of the codling moth — dodeca-8E,10E-dien-l-ol — using in the key stages Wittig reactions and the trans-hydride reduction of the triple bond of an intermediate enynol.Institute of Organic Chemistry, Academy of Sciences of the Armenian SSR, Erevan. Institute of Organic Chemistry and Biochemistry, Academy of Sciences of Czechoslovakia, Prague. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 117–123, January–February, 1991.     

Dielectric response function of GaPAs solid solutions in the vibrational absorption region

By taking spectra of IR transmission and reflection, attenuated total reflection, and Raman scattering, different models of the dielectric response function of GaPAs solid solutions are tested. It is demonstrated that the models accounting for the difference in the times of transverse and longitudinal vibrational relaxations, as well as the frequency distribution of TO phonons, make possible the prediction of the experimental spectra with a reasonable accuracy.     

Use of tin as a surfactant material for the growth of thin silver films on silicon oxide

In this letter, we report on the use of tin as an effective surfactant material for silver growing on silicon oxide. We observed that submonolayers of Sn pre-deposited on SiO₂ result in earlier film coalescence and formation of smoother Ag layers. We suggest that Sn atoms reduce the Ag-adatom mobility resulting in experimentally observed increased island density and decreased film roughness. Angle-resolved X-ray photoelectron spectroscopy reveals that Sn remains under the Ag layer giving circumstantial evidence that at later stages of Ag film growth Sn does not influence the interlayer transport.     

Approximation of classes B_{p,\theta }^r of periodic functions of one and several variables

We obtain order-sharp estimates of best approximations to the classes $B_{p,\theta }^r$ of periodic functions of several variables in the space L _q , 1 ≤ p, q ≤ ∞ by trigonometric polynomials with “numbers” of harmonics from step hyperbolic crosses. In the one-dimensional case, we establish the order of deviation of Fourier partial sums of functions from the classes $ B_{1,\theta }^{r_1 } $ in the space L ₁.     

Metalorganic vapor phase epitaxy of III–V-on-silicon: Experiment and theory

The integration of III–V semiconductors with Si has been pursued for more than 25 years since it is strongly desired in various high-efficiency applications ranging from microelectronics to energy conversion. In the last decade, there have been tremendous advances in Si preparation in hydrogen-based metalorganic vapor phase epitaxy (MOVPE) environment, III–V nucleation and subsequent heteroepitaxial layer growth. Simultaneously, MOVPE itself took off in its triumphal course in solid state lighting production demonstrating its power as industrially relevant growth technique. Here, we review the recent progress in MOVPE growth of III–V-on-silicon heterostructures, preparation of the involved interfaces and fabrication of devices structures. We focus on a broad range of in situ, in system and ex situ characterization techniques. We highlight important contributions of density functional theory and kinetic growth simulations to a deeper understanding of growth phenomena and support of the experimental analysis. Besides new device concepts for planar heterostructures and the specific challenges of (001) interfaces, we also cover nano-dimensioned III–V structures, which are preferentially prepared on (111) surfaces and which emerged as veritable candidates for future optoelectronic devices.     

Trigonometric and orthoprojection widths of classes of periodic functions of many variables

We obtain exact order estimates for trigonometric and orthoprojection widths of the Besov classes B ^r _p,θ and Nikol’skii classes Hr p of periodic functions of many variables in the space L _q for certain relations between the parameters p and q.