Effect of tempering under stress on the mechanical properties and relaxation resistance of austempered reinforcing wire

Conclusions To increase the relaxation resistance and retain high values of strength and ductility of austempered reinforcing wire it is necessary to conduct tempering under stress at stresses somewhat lower than _0.01 and temperatures of 350–380°.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 8, pp. 32–33, August, 1979.     

Determination of the characteristics of polymer decomposition using the semiinfinite body method

The problem of determining the kinetics of the decomposition and thermophysical properties of polymers from a one-dimensional temperature field is investigated. An analytic solution is obtained under the condition that the rate of decomposition depends strongly on temperature.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 41, No. 6, pp. 1078–1082, December, 1981.     

Selection of antifreeze moistener for ramming mixtures

It has been established that orthophosphoric acid, which is used as an antifreeze moistener in ramming mixtures for sand-blasting ramming of walls of steel-teeming ladles, can be replaced by an aqueous solution of sodium acetate, a waste product of the Kaluzhskii Integrated Works of Synthetic Aromatic Substances.Translated from Ogneupory, No. 2, pp. 23 – 24, February, 1994.     

Open circuit potential transients and electrochemical quartz crystal microgravimetry measurements of dissolution of copper in acidic sulfate solutions

It is demonstrated that open circuit potential transients measurements are able to give the realistic and fast information on the rate of metal corrosion. The results of the studies of the rate of copper corrosion in naturally aerated unstirred acidic sulfate solutions obtained by this method are close to the results of electrochemical quartz crystal microgravimetry measurements. It was found that within the concentration range CuSO₄: 0.001-0.01 M, H₂SO₄: 0.005-0.5 M, independently of whether 0.1 M K₂SO₄ is present in the solution or not, the rate of corrosion of thin (about several tens monolayers) and fresh deposits of copper does not depend on the solution composition and is limited by the transport of the dissolved oxygen. The rate of corrosion of such deposits sometimes exceeds the rate of corrosion of compact copper samples.     

Magnetic and structural properties of rapidly quenched Nd-Fe-Co-Ge-B alloys

We have studied the magneto-resistive effect in bulk Y_3/4Lu_1/4Ba₂Cu₃O₇ + CuO composites prepared by the fast-sintering technique. It has been found that the composites exhibit large magnetoresistance in low magnetic fields (<100 Oe) in a broad temperature range (tens of kelvins below the critical temperature T _c). The HTSC-based composites exhibit a much higher sensitivity to weak magnetic fields at liquid-nitrogen temperature as compared to pure HTSC ceramics. By choosing a proper bias current j, it is possible to control the shape of the resistivity-magnetic field ρ(H) characteristic of the composites and to vary the parameter R ₀ = {R(H = 0) ? R(H)}/R(H = 0). Under the condition j > j _c (where j _c is the critical-current density), large values of the magnetoresistance R ₀, up to thousands percent, are obtained in the range of weak magnetic fields (tens of oersteds) at 77 K. This effect is attractive for practical applications of these composite materials as active elements of magnetic-field sensors. The sign of the magneto-resistive effect is positive in contrast to that of manganese oxides. This may be important for some devices.     

Study of defects in heterostructures with GaPAsN and GaPN quantum wells in the GaP matrix

Heterostructures with GaP/GaP_{1 − x} N _x and GaP/GaP_{1 − x − y} As _x N _y quantum wells grown by the MOCVD method are studied by methods of capacitance-voltage profiling and capacitive and current deep level transient spectroscopy. In heterostructures with GaP/GaP_{1 − x} N _x quantum wells, intrinsic defects with deep levels of 0.17 and 0.08 eV are revealed. It is shown that a considerable decrease in the concentration of these defects occurs with the substitution of a ternary GaP_{1 − x} N _x alloy forming the region of the quantum well by a GaP_{1 − x − y} As _x N _y quaternary alloy. The nature of emerging defects and mechanisms of decreasing their concentration are discussed.