Function composition of modified reduced graphite oxide

Reduced graphite oxide (RGO) is prospective for application as an active material for supercapacitor electrodes due to the simple synthesis, the high specific surface area and the presence of oxygen-containing functional groups. Functionalization of such materials affects hydrophilicity, surface morphology and contributes to the redox processes when potential is applied. In this article RGO was treatment by mixture of potassium hydroxide and chloroacetic acid; hydrobromic acid and oxalic acid; in various ratio of strong nitric, sulfuric and phosphoric acids. Such functionalization of RGO leads to decrease in particle size, increase the quantity of oxygen-containing groups on the surface of the materials and affects the change of carbon hybridization from sp² to sp³. Furthermore, all the samples were investigated by cyclic voltammetry (CV) to study the redox processes occurring on the electrode material surface. The peaks on the CV curves were compared with the corresponding redox reversible reactions. Furthermore, the specific capacity of all samples was calculated. Thus, at low carboxylation level of RGO specific capacity is increased due to significant contribution of redox processes while high functionalization leads to decrease in conductivity and, as well in specific capacity.     

High-voltage electron cooler project for NICA collider

A high-voltage electron cooling system (ECS) with electron energy reaching 2.5 MeV for the NICA collider is being designed at the Joint Institute for Nuclear Research. The ECS is being developed in correspondence with the available experience in manufacturing similar systems from around the world. The main feature of this design is the use of two cooling electron beams (one beam per collider ring); electrons are accelerated and decelerated by a common high-voltage generator. A conceptual project of high-voltage ECS has been developed. The cooler consists of three tanks filled with SF₆ gas under pressure. Two of them contain electron-beam forming systems; each system consists of two electron guns, two electron collectors, and accelerating-decelerating tubes placed in a longitudinal magnetic field generated by a solenoid. The third tank contains a high-voltage generator based on the voltage-multiplying circuit.     

X-ray interferometers as a means of super-high-precision metrology (review)

The review considers the present state of the art in the field of x-ray interferometry and its potential use for detecting and measuring nanometer-scale translations of microobjects. Basic physical models used for producing and investigating x-ray wave interference and moire patterns are presented. To whom correspondence should be addressed. Institute of Electronics, National Academy of Sciences of Belarus, 22, Logoiskii Trakt, Minsk, 220841, Belarus. Translated from Zhurnal Prikladnoi Spekiroskopi, Vol. 66, No. 4, pp. 451–459, July–August, 1999.     

Modernization of Klistron Modulators of the LINAC-200 Accelerator

Physics of Particles and Nuclei Letters - The authors of the report simulated the existing modulator circuit, identified shortcomings, and developed a klystron modulator based on IJBT transistors...     

Resistance to interlayer shear of plastics on a carbon filament base

Conclusions 1. An equation has been derived for the strength during interlayer shear along reinforcing fibers of a composite material of unidirectional texture which allows calculation of this index as a function of composition of the material and state of the interphase boundary. Experimental confirmation of this equation has shown that the effectiveness of surface treatment of the reinforcing filler can be estimated by its use.2. It has been shown that the strength during interlayer shear of an epoxy-phenol plastic can be increased by a factor of more than 3, and during bending by a factor of 1.3, as the result of treatment of high-modulus carbon fibers in nitric acid.3. A correlation has been established between changes in electrical resistivity of the carbon fiber and the molecular component of adhesion to it of consolidated epoxy-phenol binder.Moscow. Translated from Mekhanika Polimerov, No. 3, pp. 445–451, May–June, 1977.     

Heavy ion linear accelerator with high-frequency quadrupole focusing

Based on results of works on the NICA/MPD (Joint Institute for Nuclear Research, Dubna) project, the possibility of designing a heavy ion linear accelerator with high-frequency quadrupole focusing both in the input part and in the main part of the accelerator is shown. Parameters of the linear ¹⁹⁷Au³¹⁺ ion accelerator are presented. Special attention is paid to technical questions of calculating, designing, manufacturing, and tuning the accelerator.     

Development of the Low Energy Particle Toroidal Accumulator project

The Low Energy Particle Toroidal Accumulator (LEPTA), a positron storage ring with electron cooling, was constructed and put in operation at the Joint Institute for Nuclear Research (Dubna). The storage ring is a generator of directed beams of ortho-positronium (o-Ps) produced upon the recombination of the beam of positrons circulating in the storage ring with a single-pass electron beam. In 2004 the storage ring was put in operation with the circulating electron beam. The source of positrons of the positron injector was tested with a new radioactive source delivered from South Africa. The positron trap was put in operation for electrons. The electron cooling system was tested with a pulsed electron beam. The progress in commissioning LEPTA is described in this paper.