Chemoselective Ruthenium‐Catalyzed Reduction of Acid Chlorides to Aldehydes with Dimethylphenylsilane

A variety of aromatic and alkyl acid chlorides can be selectively converted into aldehydes using dimethylphenyl silane (HSiMe₂Ph) as the reducing reagent in the presence of the cationic ruthenium catalyst {Cp[(i‐Pr)₃P]Ru(NCMe)₂}⁺ [PF₆]⁻. The reactions proceed under very mild conditions and are tolerant to many functional groups.     

Structural studies of ribosomal proteins

Crystal and solution structures of fourteen ribosomal proteins from thermophilic bacteria have been determined during the last decade. This paper reviews structural studies of ribosomal proteins from Thermus thermophilus carried out at the Institute of Protein Research (Pushchino, Russia) in collaboration with the University of Lund (Lund, Sweden) and the Center of Structural Biochemistry (Karolinska Institute, Huddinge, Sweden). New experimental data on the crystal structure of the ribosomal protein L30 from T. thermophilus are also included.     

Cold crucible melting and characterization of titanate-zirconate pyrochlore as a potential rare earth/actinide waste form

La-Ce-Gd titanate-zirconate pyrochlore-based ceramics was synthesized at the lab-scale inductive melting unit with a 56?mm inner diameter cold crucible. Batch feeding rate and melting ratio were 3?kg/h and 3?kW?h/kg respectively. The ceramics is composed of 85–90?vol% zoned grains of the pyrochlore structure phase, the sample has excellent chemical durability in hot water and may be considered as a promising matrix for actinide – rare earth fraction of high level waste.     

Optoelectronic Method of Noncontacting Reconstruction of the Profile of a Surface of Three Dimensional Objects of Large Dimensions

An optoelectronic method is considered for noncontacting reconstruction of the surface profile of three-dimensional objects of large dimensions. The optimal conditions for performing measurements are identified. It is shown that the proposed method, in contrast to the already known methods, does not require fine tuning of the equipment. A numerical method is given for compensating distortions caused by aberrations. A method is described for reconstructing the surface profile cell by cell which increases the accuracy of measurements.     

A method of determining the critical value of the J-integral under conditions of stable crack growth

A method is given for determining cracking resistance based on the strain diagram for stable crack growth; the specimen is loaded to give a set rate of crack extension or with given speed for the clamps. The critical value of the Jintegral has been determined by calculating the work of strain for a hypothetical specimen composed of a nonlinearly elastic material whose cracking resistance is equal to that of the actual one. Two forms of implementation are considered: simplified and numerical. The results are compared with those from standard methods and show that the proposed method is promising as it can be based on tests on a single specimen with a simple technique.Translated from Problemy Prochnosti, No. 3, pp. 18–25, March, 1992.     

Composition and Band Structure of the Native Oxide Nanolayer on the Ion Beam Treated Surface of the GaAs Wafer

Detailed information on GaAs oxide properties is important for solving the problem of passivating and dielectric layers in the GaAs-based electronics. The elemental and chemical compositions of the native oxide layer grown on the atomically clean surface of an n-GaAs (100) wafer etched by Ar⁺ ions have been studied by synchrotron-based photoelectron spectroscopy. It has been revealed that the oxide layer is essentially enriched in the Ga₂O₃ phase which is known to be a quite good dielectric as compared to As₂O₃. The gallium to arsenic ratio reaches the value as high as [Ga]/[As] = 1.5 in the course of oxidation. The Ga-enrichment occurs supposedly due to diffusion away of As released in preferential oxidation of Ga atoms. A band diagram was constructed for the native oxide nanolayer on the n-GaAs wafer. It has been shown that this natural nanostructure has features of a p–n heterojunction.     

Analysis of Current–Voltage Characteristics in UV AlGaN Heterostructure FPAs

Journal of Communications Technology and Electronics - UV visible-blind and solar-blind 320 × 256 photodiode arrays based on AlxGa1 – xN heteroepitaxial structures (AlGaN HES) and...     

A frequency converter with controllable characteristics

The area of practical application of measuring instruments with frequency conversion, in which the economic costs of their operating cycle are related to the control of the accuracy of the converters, is considered. Methods of constructing stroboscopic frequency converters, adapted to a specific class of measurement problems with respect to the “accuracy” parameter, are described. __________ Translated from Izmeritel’naya Tekhnika, No. 1, pp. 47–51, January, 2008.