Filtration combustion of porous metallic samples in a gas diluted by an inert component

Filtration combustion of a porous layer with natural filtration of the oxidizer diluted by an inert component is studied. The problem of ignition of a porous layer by a heated surface permeable for the gas is solved, and the time of ignition is determined as a function of pressure in the reactor and initial porosity of the sample. Formation of an inert gas “plug” preventing chemical interaction is examined. It is shown that the mean depth of conversion of the condensed reagent in the porous layer depends on the sample length, porosity, pressure of the gas mixture, and concentration of the inert component. __________ Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 1, pp. 73–79, January–February, 2008.     

Dismantling the lining of an electrolyzer cathode unit for aluminum production using hydraulic press equipment and diamond cutting tools

Technology is considered for dismantling the lining of a aluminum electrolyzer cathode unit for major overhaul directly within the electrolyzer building. In order to accelerate breakdown of the lining and reduce the effect of impact and vibration loads during dismantling on the neighbourhood during repair of the electrolyzer, cathode dismantling is performed using hydraulic press equipment for impact-free breaking of materials using diamond tools for cutting and boring. Acceleration of dismantling is achieved as a result of the use of hydraulic equipment making it possible to create within the electrolyzer cathode lining material local nonuniform pressure distribution providing crack formation breaking the integrity of the lining.     

Determination of the parameters of deep levels using the differential coefficients of the current-voltage characteristics

Deep levels were determined in GaP light-emitting diodes using the differential coefficients of the current-voltage characteristics. The parameters determined by different methods showed agreement. The measurement conditions are such that the measurements can be made using wafers, which makes the proposed methods extremely promising. Pis’ma Zh. Tekh. Fiz. 25, 22–27 (March 12, 1999)     

Possibility of nonequilibrium phase transitions in semiconductors and semiconducting superstructures in crossed electric and magnetic fields

An analysis is made of two types of negative differential conductivity in semiconductors and semiconducting superstructures containing ND shallow impurity atomic systems (centers), in crossed electric and magnetic fields corresponding to nonequilibrium phase transitions of n _e , where n _e is the average density of nonequilibrium carriers (electrons). It is observed that these semiconductors and semiconducting superstructures in crossed electric and magnetic fields may be used to fabricate various semiconductor devices and apparatus, and also memory elements for the acquisition, storage, and protection of information under extreme conditions. Pis’ma Zh. Tekh. Fiz. 25, 39–44 (August 26, 1999)     

Thin-film multilayer magnetic sensors based on the anisotropic magnetoresistive effect

The design and operation of thin-film multilayer sensors based on the anisotropic magnetoresistive effect are considered from the theoretical and experimental viewpoints.     

Use of mechanoactivation for obtaining hydrides of titanium aluminides

The hydrogen storage capacity of titanium aluminides Ti(Al,Nb) (β₀) and Ti₃ (Al,Nb) (α₂) subjected to mechanoactivation has been investigated. It has been found that the mechanoactivation in a hydrogen atmosphere makes it possible to obtain hydrides of titanium aluminides with a hydrogen concentration of up to 1.8 wt % at room temperature without enhanced requirements for purity and pressure of the supplied hydrogen. The release of hydrogen from such samples in a vacuum begins at a temperature of about 175°C.     

Clock aligner based on delay locked loop with double edge synchronization

In CMOS multistage clock buffer design, the duty-cycle of clock is liable to be changed when the clock passes through several buffer stages. The pulse-width may be changed due to unbalance of the p- and n-OS transistors in the long buffer. This paper describes a delay locked loop with double edge synchronization for use in a clock alignment process. Results of its SPICE simulation, that relate to 1.2 μm CMOS technology, shown that the duty-cycle of the multistage output pulses can be precisely adjusted to (50 ± 1)% within the operating frequency range, from 55 MHz up to 166 MHz.     

Microwave pulses compressed in a barrel-shaped resonator with screw corrugation

The microwave pulse compressor proposed previously [1], having the form of an oversized waveguide resonator with a screw-corrugated inner surface, was constructed and experimentally tested. A fivefold compression of microwave pulses with a 70% efficiency was obtained in a 3-cm wavelength range.