Refractories for an argon-oxygen steel refining unit

Conclusions As a result of investigations of a number of periclase-chromite refractories, the best of them based on a combination of high-temperature strength characteristics, a melted periclase-chromite material was determined. The experimental parts were tested in the tuyere zone of a 10-ton converter in gas-oxygen refining of stainless steels. The experimental linings had a third the wear of linings of periclase-spinel parts. The parts developed were recommended for lining the bottom of a 50-ton argon-oxygen refining unit.N. A. Myakisheva, S. N. Makhonina, Yu. N. Finogenov, and A. A. Malyutin, Colleagues in the Eastern Refractory Institute, participated in the work.Translated from Ogneupory, No. 3, pp. 37–41, March, 1982.     

An analysis of the conditions for the formation of an internal interface and their effect on the freezing point of zinc

The effect of the conditions for the formation of an internal interface on the freezing point of zinc of 99.9999% purity for different intensities of the removal of heat from the zinc in the thermometer channel is investigated. Comparative measurements without the formation of an internal interface were carried out. The difference between the maximum values of the measured temperatures reached approximately 1 mK. The reasons for these differences are considered.Translated from Izmeritelnaya Tekhnika, No. 11, pp. 43–45, November, 2004.     

Electropolymerized flavin adenine dinucleotide as an advanced NADH transducer

Electropolymerizing the prosthetic group (flavin adenine dinucleotide, FAD) responsible in the active sites of dehydrogenases for NAD(+)|NADH regeneration, we succeeded in mimicking enzyme activity. Poly(FAD) characterized by an additional polymer-type redox reaction has been discovered as a highly effective electrocatalyst for NADH oxidation: operating at the lowest potentials reported for NADH transducers (0.00 V, pH 7.4), poly(FAD) is characterized by the electrochemical rate constant of 1.8 +/- 0.6 x 10(-3) cm s(-1), which is at the level of the NADH mass-transfer constant. Flow injection analysis of NADH with the poly(FAD)-modified wall-jet electrode as a detector has been characterized by a linear calibration range prolonged down to 5 x 10(-7) M and a sensitivity of 0.08 A M(-1) cm(-2), which taking into account the dispersion coefficient ( approximately 3), is at the diffusion-limiting value. In contrast to the low molecular weight mediators able to exhibit similar electrocatalytic properties, poly(FAD)-modified electrodes are characterized by the dramatically improved stability and, thus, can be considered as the most advantageous NADH transducers for analytical chemistry.     

Dielectric and Piezoelectric Properties of Pb(Mg1/3Nb2/3)O3–PbTiO3–Pb(Mg1/2W1/2)O3 Ceramics

Data are presented on the phase composition, crystal structure, microstructure, and dielectric and piezoelectric properties of (1 – y)[(1 – x)Pb(Mg_1/3Nb_2/3)O₃–xPbTiO₃]–yPb(Mg_1/2W_1/2)O₃ (x = 0.30–0.36; y = 0, 0.05, 0.10) ceramics. It is shown that the use of fine-particle magnesia as a starting reagent ensures the formation of single-phase materials. The ceramics with a rhombohedral structure are found to exhibit relaxor behavior. Increasing the content of the Pb(Mg_1/2W_1/2)O₃ perovskite leads to ordering of the domain structure of poled ceramics and increases their piezoelectric charge coefficient d ₃₁ and the width of their phase transitions.