Pressure dependence of the sound velocity in distilled water

The sound velocity is measured in distilled water in the pressure range 0.1–60 MPa and in the temperature range 0–40°C. The results are given in the form of tables and an equation derived by least-squares processing of the experimental data. Translated from Izmeritel'naya Tekhnika, No. 4, pp. 66–69, April, 1999.     

The influence of the coprecipitation conditions on the low-temperature formation of barium hexaferrite

We have investigated the formation of barium hexaferrite via the coprecipitation method. Various reagent salts and solvents were tested, and the coprecipitates were calcined at 300–800 °C for 1–50 h. The samples were characterized with X-ray powder diffraction, electron microscopy and magnetometry. The coprecipitation conditions had a significant influence on the formation time of the barium hexaferrite, which started to form at as low as 500 °C. The optimum coprecipitation conditions were: ethanol as a solvent and chlorides as reagent salts. Powders with optimum magnetic properties, saturation magnetization 60–63 emu/g and coercivity 4–5 kOe, were obtained by calcining at 600–700 °C.     

Method for calculating the spectrum of scattered photons under conditions of aerialγ-mapping

An analytical method for calculating the spectrum of multiply scattered γ-radiation of radioactive isotopes distributed in soil is proposed. Expressions for intensities of fluxes of photons scattered n times are obtained in the form of sums of multiple integrals of a simple form. The integration is performed numerically. Results of calculations of test examples are presented. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 71, No. 3, pp. 551–558, May–June, 1998.     

A program for identifying the form of the distribution law of random quantities and their modeling

A program for identifying the form of the distribution law of a random quantity is described. The dependence of the optimum number of intervals when constructing histograms from a volume of the sample (10–100,000) and of the kurtosis (in the limits 2–9.65) is determined by computer modeling. Using 50 different functions, the program can also model random quantities with unimodal and bimodal distribution laws. __________ Translated from Izmeritel’naya Tekhnika, No. 5, pp. 9–14, May, 2007.     

The effects of third alloying elements on the bulk Ag<Subscript>3</Subscript>Sn formation in slowly cooled Sn–3.5Ag lead-free solder

The effects of third alloying elements (Cu, In, Zn) on the formation of bulk Ag₃Sn intermetallic compounds (IMCs) in slowly cooled Sn–3.5Ag lead-free solder were investigated by microstructural observation and thermal analysis technique. Microstructural observation shows that bulk Ag₃Sn IMCs existed in the microstructure of slowly cooled Sn–3.5Ag, Sn–3.5Ag–0.75Cu and Sn–3.5Ag–1.5In alloys, while no bulk Ag₃Sn IMCs formed in the slowly cooled Sn–3.5Ag–2.0Zn alloys. Thermal analysis results indicate that Ag preferably reacted with Zn to form Ag–Zn IMCs at high temperature rather than reacted with Sn to form Ag₃Sn plate.     

Experimental study of the plasmochemical method for the direct production of silicon from quartz

The results of experimental studies of the nonequilibrium plasmochemical method for production of polycrystalline silicon from quartz are presented. It is shown that polycrystalline silicon in the form of spherelike particles with an average size of 100–200 μm and purity of 99.8–99.9% can be obtained with a yield of up to 60% using the electric arc installation developed.     

Approximation of the time form of a laser pulse using finite functions

The influence of the time form of a surface heat source on the distribution of the temperature field in a homogeneous half-space is investigated. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 79, No. 1, pp. 178–184, January–February, 2006.     

Synthesis of non-equilibrium phases in immiscible metals mechanically mixed by high pressure torsion

The structural changes in mechanically mixed metals of immiscible combinations of elements caused by bulk mechanical alloying (MA) through the use of high pressure torsion (HPT) were investigated in Ag–Ni and Nb–Zr systems. There was no alloying between Ag and Ni on atomic scale even after 100 rotations of HPT. On the other hand, the β-Zr phase started to appear after HPT 2 rotations in the Nb–Zr system, even though β-Zr is a high temperature phase. Further, Nb and Zr were completely mixed to form a bcc structured single phase after HPT 100 rotations. The sequence of alloying in the Nb–Zr system during HPT was discussed. These results clearly suggest that non-equilibrium phases can form in the Nb–Zr system by bulk MA by the use of HPT.     

Decarbonization mechanisms of polycarbosilane during pyrolysis in hydrogen for preparation of silicon carbide fibers

Polycarbosilane (PCS) fibers are cured by electron beam irradiation in helium. Then, the cured fibers are pyrolyzed under hydrogen. The mechanisms of carbon removal during pyrolysis are investigated using chemical elemental analysis, FTIR, Raman, and AES analysis. The development of microstructure and phase is examined by SEM, TEM, and XRD. The results show that the thermal cleavage of relatively weak Si–H and Si–CH₃ bonds takes place first during pyrolysis in hydrogen, generating free radicals. The free radicals then react with C–H bonds or with each other to form Si–CH₂–Si groups, releasing hydrogen and methane. As temperature increases, the Si–CH₂–CH₂–Si groups in PCS begin to dissociate and react with hydrogen to form methane, resulting in the further removal of carbon and giving silicon-rich silicon carbide fibers (i.e. C/Si <1).     

A mathematical model of the accumulation of damages and a criterion of the limiting state of metals and alloys in active plastic deformation under conditions of proportional loading

A mathematical model of the accumulation of damages in active plastic deformation and also a criterion of the limiting state of metals and alloys taking into consideration the form of loading are given. Translated from Problemy Prochnosti, No. 1, pp. 49–57, January–February, 1997.     

Analysis of the systematic errors of measurements of the caloricity of natural gas

A catalytic calorimeter is developed in explosion-protected form for precision measurements of the quality of natural gas. __________ Translated from Izmeritel’naya Tekhnika, No. 5, pp. 49–55, May, 2007.     

Effects of Ga,Al, Ag,and Ce multi-additions on the properties of Sn–9Zn lead-free solder

Wetting balance method is used to evaluate the effects of Ga, Al, Ag, and Ce multi-additions on the solderability of Sn–9Zn lead-free solders, results show that the optimal addition amounts of Ga, Al, Ag, and Ce is 0.2, 0.002, 0.25, and 0.15 wt% respectively. The surface property of Sn–9Zn–0.2Ga–0.002Al–0.25Ag–0.15Ce solder is studied by X-ray photoelectron spectroscopy and auger electron spectroscopy analysis; results indicate that Al aggregates on the surface as a compact aluminum oxide film which prevents the further oxidation. The aggregation of Ce on the subsurface can reduce the surface tension of solder, and improve the solderability accordingly. Meanwhile, SEM and XRD analysis indicate that Cu₅Zn₈ and AgZn₃ intermetallic compounds form at the interface between Sn–9Zn–0.2Ga–0.002Al–0.25Ag–0.15Ce solder and Cu substrate, while AuZn₃ and AuAgZn₂ form at the interface between solder and Cu/Ni/Au substrate. Moreover, results also indicate that the mechanical property of soldered joints is improved duo to the dispersion strengthening effects of AgZn₃ in Sn–9Zn–0.2Ga–0.002Al–0.25Ag–0.15Ce solder.     

Large n-Expansion Limit of the Three-Dimensional Ferromagnetic Quantum Phase Transition

We use the large n-expansion method to study the role of the long-range interaction, topological and dissipation effects for the case of an itinerant quantum ferromagnet in the limit of the Landau–Ginzburg–Wilson theory. In the one-loop approximation, we calculate the explicit form of the electronic self-energy as a result of electron–fluctuation interaction and extract the temperature dependence of the scattering time. The temperature dependence of the relative resistivity shows that both the dissipative and topological terms of the action determine the non-Fermi behavior of the system in the critical region around the quantum phase transition.      

Reliability studies of Sn–9Zn/Cu and Sn–9Zn–0.3Ag/Cu soldered joints with aging treatment

In this study, the interfacial reactions and joint reliabilities of Sn–9Zn/Cu and Sn–9Zn–0.3Ag/Cu were investigated during isothermal aging at 150 °C for aging times of up to 1,000 h. Cu₅Zn₈ IMCs layer is formed at the as-soldered Sn–9Zn/Cu interface. Adding 0.3wt.% Ag results in the adsorption of AgZn₃ on the Cu₅Zn₈ IMCs layer. The as-soldered Sn–9Zn/Cu and Sn–9Zn–0.3Ag/Cu joints have sufficient pull strength. The thickness of the IMCs layer formed at the interface of Sn–9Zn/Cu and Sn–9Zn–0.3Ag/Cu both increase with increasing aging time. Correspondingly, both the pull forces of the Sn–9Zn and Sn–9Zn–0.3Ag soldered joints gradually decrease as the aging time prolonged. However, the thickness of the IMCs layer of Sn–9Zn–0.3Ag/Cu increases much slower than that of Sn–9Zn/Cu and the pull force of Sn–9Zn–0.3Ag soldered joint decreases much slower than that of Sn–9Zn soldered joint. After aging for 1,000 h, some Cu–Sn IMCs form between the Cu₅Zn₈ IMC and the Cu substrate, many voids form at the interface between the Cu₅Zn₈ layer and solder alloy, and some cracks form in the Cu₅Zn₈ IMCs layer of Sn–9Zn/Cu. The pull force Sn–9Zn soldered joint decreases by 53.1% compared to the pull force measured after as-soldered. Fracture of Sn–9Zn/Cu occurred on the IMCs layer on the whole and the fracture micrograph implies a brittle fracture. While the pull force of Sn–9Zn–0.3Ag soldered joint decreases by 51.7% after aging at 150 °C for 1,000 h. The fracture mode of Sn–9Zn–0.3Ag soldered joint is partially brittle at the IMCs layer, and partially ductile at the outer ring of the solder.     

The neutron spectra of nuclear facilities as the superposition of physically validated spectra

Neutron energy spectra in the energy range 10⁻¹⁰–18 MeV for 100 neutron fields of nuclear reactors and neutron generators are re-established. A method of forming the a priori spectrum in the form of the superposition of physically validated neutron spectra is used in the calculation. __________ Translated from Izmeritel’naya Tekhnika, No. 6, pp. 60–66, June, 2006.     

Extraction of indicator traces on the images obtained in the course of control with penetrating agents

We propose a method for the segmentation of the images of indicator traces on a surface obtained in the course of recording the results of liquid-penetrant control in the form of a digital image. This method is based on the use of statistical characteristics of the samples of points belonging to the foreground and background in the apparatus for constructing matting α-matrices. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 43, No. 4, pp. 112–116, July–August, 2007.     

Influence of minor Bi additions on the interfacial morphology between Sn–Zn–xBi solders and a Cu layer

The influence of minor Bi additions on the interfacial morphology between Sn–Zn–xBi (x = 0, 1, 3) solders and a Cu layer after reflowing were investigated by microstructural observations. The addition of minor amount of Bi into Sn–Zn solder reduced the tendency to form cracks at the solder/Cu interface. This is because alloying with Bi reduced the mismatch of the coefficient of thermal expansion (CTE) between the solder alloys and the Cu plate. Moreover, the Sn–Zn solder with Bi reduced the melting temperature of the solder alloy, and, this resulted in the coarsening of the gains and thickening of the intermetallic compound (IMC) layers because solder alloys with a lower melting temperature experienced a longer molten period during reflow. Because the Bi atoms accumulated at the surface of the IMC layers in homogeneously, partially impeding the IMC dissolving into the molten solder, a serrated-like Cu–Zn–Sn IMC layer was formed at the Sn–8Zn–3Bi/Cu interface.     

A method for the determination of the elastic equilibrium of isotropic bodies with curvilinear inclusions. Part 3. Antiplane deformation

Within the framework of the approach proposed by L. P. Mazurak, L. T. Berezhnyts'kyi, and P. S. Kachur [“Method for determination of elastic equilibrium of isotropic bodies with curvilinear inclusions. Part 1. Mathematical foundations,”Fiz.-Khim. Mekh. Mater.,33, No. 6, 21–31 (1997)], we construct a new method for the determination of elastic equilibrium of cylindrical bodies with noncanonical curvilinear foreign elastic inclusions under conditions of longitudinal shear. Unlike the method of perturbation of the form of a boundary, this method imposes no restrictions on the form of inclusions. The method is based on a procedure of determination of contour integrals of the Cauchy type by using the Faber polynomials. Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 35, No. 2, pp. 21–26, March–April, 1999.     

Influence of the concentration of a dispersed phase and of the magnetic field on the attenuation of ultrasonic waves in magnetic fluids

The regularities of the propagation of elastic waves of ultrasonic range in magnetic fluids have been experimentally established. The influence of relaxation processes — nonlocal heat exchange and viscous dissipation — on the coefficient of attenuation of sound has been revealed and a comparison to the existing theoretical data has been made. The dependences (anisotropic in form) of the attenuation of the wave’s amplitude on the value and direction of the magnetic field have been determined and an interpretation of the results obtained has been proposed. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 5, pp. 133–140, September–October, 2007.     

A method for the solution of the problem of heat conduction for temperature peaks

The solution of the heat conduction equation with boundary conditions of the second kind obtained in the form of Wiener integrals is reduced to Lebesgue integrals. We analyze the behavior of this solution for different models of heat generation and heat transfer in the process of friction. Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 34, No. 2, pp. 97–104, March–April, 1998.