The aligned Si nanowires growth using MW plasma enhanced CVD

New and simple modification of vapor-liquid-solid process for Si nanowires growth based on microwave plasma enhanced chemical vapor deposition that uses solid-state Si target as a source of Si atoms was developed. The method was temperature and pressure controlled evaporation of solid phase of Si source in hydrogen microwave plasma. Aligned growth of Si nanowires was performed in local electric field by applying of constant negative bias to substrate holder. Deposited Si nanowires were studied by scanning electron microscopy (SEM), Raman and photoluminescence spectroscopy. Correlation between photoluminescence spectra and Si nanowires properties were studied.     

Status of Work on the VÉPP-5 Injection Complex

The VÉPP-5 injection complex under construction at the Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences is a powerful source of intense electron and positron bunches at 510 MeV, which covers all needs of the electron–positron colliding beam setups currently operating and under construction at the Institute of Nuclear Physics. The complex includes a 285 MeV linear electron accelerator, a 510 MeV linear positron accelerator, and an accumulator–cooler with beam injection and ejection channels. Intense work on the design, assembly, and tuning of the linear electron accelerator has been conducted in the last 2 yr. As a result, by August 2002 the linear electron accelerator was put into operation with all standard subsystems. By this time, the isochronous achromatic turning of the electron beam, a system for converting electrons into positrons, and the first accelerating structure of the linear positron accelerator were assembled and put into operation. All this made it possible to accelerate the positron beam up to 75 MeV. Preliminary results of tests of the linear accelerators are presented.     

Development of equipment for heat treatment of carbon fibres

Conclusions 1. Adequate experience and knowledge has been accumulated in the Khimtekstil'mash NPO to make it possible to develop equipment for the manufacture of CF which conform to the contemporary world level. In recent years work on developing new equipment and improving existing equipment for the manufacture of CF have not received new development because of the lack of financing. One must also note the decrease in tempo of work on technological assurance, which is reflected in the technical level of equipment being developed.2. In connection with the high cost of work on developing new technologies and equipment for the manufacture of CF, these problems require solution at the state and in first-state level, since CF are materials not only for the present but also mainly for the future.Deceased.Khimtekstil'mash NPO (Chernigov). Translated from Khimicheskie Volokna, No. 5, pp. 33–35, September–October, 1993.     

Granulometric Analysis of Powder Materials Used for Producing Samples by Method of Selective Laser Melting

Metallurgist - The paper discusses the aspects of granulometric and morphological analysis of powders used in the technology of selective laser melting. Studies have been carried out to obtain...     

Unfired dolomite refractories with increased hydration resistance

Conclusions The use of dolomite burnt in grain form for the manufacture of unfired goods with a tar bond makes it possible to obtain refractories with a high hydration resistance and with high physicomechanicai properties. Coal tar with a 65–70% pitch content should be used as a bonding agent.Sintered grain dolomite should be added to the batch without being ground, preferably in combination with finely ground metallurgical magnesite or magnesite-dolomite clinker.     

Introduction of a method of rammed linings of 230-ton steel teeming ladles

Refractories and Industrial Ceramics -     

Layer-by-layer composition and structure of silicon subjected to combined gallium and nitrogen ion implantation for the ion synthesis of gallium nitride

The composition and structure of silicon surface layers subjected to combined gallium and nitrogen ion implantation with subsequent annealing have been studied by the X-ray photoelectron spectroscopy, Rutherford backscattering, electron spin resonance, Raman spectroscopy, and transmission electron microscopy techniques. A slight redistribution of the implanted atoms before annealing and their substantial migration towards the surface during annealing depending on the sequence of implantations are observed. It is found that about 2% of atoms of the implanted layer are replaced with gallium bonded to nitrogen; however, it is impossible to detect the gallium-nitride phase. At the same time, gallium-enriched inclusions containing ～25 at % of gallium are detected as candidates for the further synthesis of gallium-nitride inclusions.     

Gibbs random fields on a lattice: Definitions,existence, uniqueness,and phase transitions (a review of proceedings of the seminar on statistical physics at the faculty of mechanics and mathematics of the Moscow state university in 1962–1994)

The Moscow Grand Seminar on Statistical Physics is one of the first seminars in the world devoted to rigorous methods in statistical physics. The achievements of the seminar can be appreciated in full measure from publications by the leaders of the seminar (R.L. Dobrushin, V.A. Malyshev, R.A. Minlos, Ya.G. Sinai). This paper presents a review (far from complete) of the proceedings of the seminar. The emphasis is made on the fundamental definitions and most important results.     

Density distribution at the detonation front of cylindrical charges of small diameter

A synchrotron radiation based technique is use to study the density distribution at the detonation front and its neighborhood for condensed explosives. Particular data are obtained on the structure of the detonation front in TNT, RDX, and an alloy of TNT with RDX; a comparison of the data with those obtained using different techniques confirms the correctness of the technique. It is concluded that adequate information on the structure of the chemical-reaction zone can be obtained for charges of small diameter. At the same time, it is shown that the Chapman-Jouguet parameters for such charges are far from their predicted values for an infinite medium. The results of the work, including those on the curvature of the detonation front in charges of small diameter, supplement the existing knowledge of the detonation transformation in condensed explosives. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 2, pp. 91–99, March–April, 2007.