Technique of Determination of the Piezoelectric Modulus d 33 and Investigation of the Limits of its Use

The classification of the piezoelectric modulus measurement methods for different loading regimes is investigated. It is established that the quasi-static methods make it possible to determine the static piezoelectric constants with the minimum errors. An improved method of measuring the piezoelectric modulus d ₃₃ in the quasi-static regime is developed. The method ensures the minimum effect of changes in the domain orientation and transition processes. Dependences of d ₃₃ on the level of mechanical stresses _n are obtained for TsTS-19, TsTS-23, and TsTBS-3 piezoceramics and it is shown that their nature depends of the ferro-rigidity of the piezoceramics composition. Features of the dependences d ₃₃( _n ) associated with the variation of the contact area of piezoelectric elements in the process of measurements and the effect of changes in the domain orientation are revealed. It is shown that the lower boundary of the compression force amounts to 2 MPa for TsTS-19. It is also established that the optimum dimension of the piezoelectric elements in determining d ₃₃ must satisfy the condition 0:45 < < 1:75. It is calculated that the error in measurements of d ₃₃ in accordance with the method proposed is 4.5% with the confidence probability of 95%.     

The effect of cold plastic deformation and subsequent annealing on the magnetic properties of metals with different initial structures

The effect of the degree of cold plastic deformation (CPD) and the temperature of subsequent annealing on the coercive force, relaxation magnetization, and relaxation magnetic susceptibility of iron and nickel is studied. The effect of the degree of CPD on steels with different initial structures in the annealed state (such as ferrite (M 10 steel), pearlite (X15 steel), and ferrite-pearlite (50 steel) structure), as well as on 50steel with different initial structures obtained after quenching and tempering at different temperatures, is also studied. The dependences obtained are analyzed based on modern theories of magnetic hysteresis for magnetically soft materials. Recommendations for the use of nondestructive testing of the degree of CPD of articles (semifinished items) made from steels with different initial structures are given.Translated from Defektoskopiya, Vol. 40, no. 9, 2004, pp. 51–62. Original Russian Text Copyright © 2004 by Bida, Sazhina.     

An Automated Setup for Investigating the Temperature Dependence of the Permittivity Spectra of Polar Liquids in the Range of 0.1–1.25 GHz

An automated setup for measurements of the temperature dependences of permittivity spectra is described. It uses an irregular microstrip resonator and allows measurements to be performed at a junction of methods using lumped elements and electrodynamic systems with distributed parameters. Measurements can be carried out without expensive thermostabilization devices in the temperature range of 200–350 K with a step of 1 K. The temperature dependences of the permittivity of polar liquids—water, methanol, and ethanol, whose dielectric relaxation regions lie within the frequency range of 0.1–1.25 GHz—are presented. Comparing the measured values of the permittivity to the Debye curve calculated from the reference data shows agreement within the limits of 3% for and 1% for . The random error of measurements was 2–3% for and 5–7% for .     

Temperature measurement in orthogonal metal cutting

Orthogonal cutting experiments were carried out on steel at different feedrates and cutting speeds. During these experiments the chip temperatures were measured using an infrared camera. The applied technique allows us to determine the chip temperature distribution at the free side of the chip. From this distribution the shear plane temperature at the top of the chip as well as the uniform chip temperature can be found. A finite-difference model was developed to compute the interfacial temperature between chip and tool, using the temperature distribution measured at the top of the chip.Nomenclature contact length with sticking friction behaviour [m] - c specific heat [J kg^–1 K^–1] - contact length with sliding friction behaviour [m] - F _P feed force [N] - F _V main cutting force [N] - h undeformed chip thickness [m] - h _c deformed chip thickness [m] - i,j denote nodal position - k thermal conductivity [W m^–2 K^–1] - L chip-tool contact length [m] - p defines time—space grid, Eq. (11) [s m^–2] - Q _C heat rate entering chip per unit width due to friction at the rake face [W m^–1] - Q _T total heat rate due to friction at the rake face [W m^–1] - Q _% percentage of the friction energy that enters the chip - q ₀ peak value ofq(x) [W m^–2] - q _e heat rate by radiation [W] - q(x) heat flux entering chip [W m^–2] - t time [s] - T temperature [K] - T _C uniform chip temperature [°C] - T _max maximum chip—tool temperature [°C] - T _mean mean chip—tool temperature [°C] - T _S measured shear plane temperature [°C] - x,y Cartesian coordinates [m] - V cutting speed [m s^–1] - V _C chip speed [m/s] - rake angle - ,, control volume lumped thermal diffusivity [m² s^–1] - emmittance for radiation - exponent, Eq. (3) - density [kg m^–3] - Stefan-Boltzmann constant [W m^–2 K⁴] - (x) shear stress distribution [N m^–2] - shear angle     

Thermal modeling of the metal cutting process: Part I — Temperature rise distribution due to shear plane heat source

The model of an oblique band heat source moving in the direction of cutting, first introduced by Hahn (Proceedings of First U.S. National Congress of Applied Mechanics 1951. p. 661–6) for an infinite medium in 1951 and subsequently modified by Chao and Trigger (Transactions of ASME 1953;75:109–20) in 1953 for a semi-infinite medium, is extended in this investigation by including appropriate image heat sources. It is used for the determination of the temperature rise distribution in the chip and the work material near the shear plane caused by the main shear plane heat source in orthogonal machining of a continuous chip. A new approach is taken in that the analysis is made in two separate parts, namely, the workmaterial side and the chip side of the shear plane and then combined. The workmaterial (or the chip) is extended past the shear plane as an imaginary region for continuity to determine the temperature distribution in the workmaterial (or the chip) near the shear plane. The imaginary regions are the regions either of the workmaterial that was cut by the cutting tool prior to this instance and became the chip or will be cut by the cutting tool prior to becoming the chip. An appropriate image heat source with the same intensity as the shear plane heat source is considered for each case. The temperature distributions in the chip and the workmaterial were determined separately by this method and combined to obtain isotherms of the total temperature distribution (and not merely the average temperatures). It appears that the significance of Hahn's ingenious idea and his general solution have not been fully appreciated; instead, an approximate approach involving heat partition between the chip and the work was frequently used (Trigger and Chao. Transactions of ASME 1951;73:57–68; Loewen and Shaw. Transactions of ASME 1954;71:217–31; Leone. Transactions of ASME 1954;76:121–5; Nakayama. Bulletin of the Faculty of Engineering National University of Yokohama, Yokohama, Japan, 1956;21:1–5; Boothroyd. Proceedings of the Institution of Mechanical Engineers (Lon) 1963;177(29):789–810). It may be noted that in utilizing Hahn's modified solution, it is not necessary to make an explicit a priori assumption regarding partitioning of heat between the workmaterial and the chip, as was common in most prior work. Instead, this information is provided as part of the solution. The results obtained with the exact analysis were compared with other methods using the experimental data available in the literature to point out some of the discrepancies in the simplified models. It may be pointed out that these models assume the temperature rise at the chip–tool interface to be nearly uniform and equals the average temperature rise in this volume. A comparison of the calculated temperature rise by these methods with the exact analysis indicates that the differences can be quite significant (50% or higher). It is hoped that future researchers would recognize the significance and the versatility of the exact analysis in determining the temperature distribution in the shear zone in metal cutting.     

A Densimeter for Precision Measurements of Densities of Liquids with an Increased Elasticity of Intrinsic Saturated Vapors

A vacuum two-capillary densimeter intended for precision measurements of densities of liquids with an increased elasticity of intrinsic saturated vapors is described. The densimeter design makes it possible to fill it in the operation mode without the occurrence of bulk or wall pockets with intrinsic saturated vapors. The temperature and concentration dependences of densities of Na–K–Cs alloys measured with this densimeter have demonstrated a high reliability of the device and accuracy of the obtained results. The measurement error is within 0.1%.     

Exoemission Testing of Violations of the Stoichiometry in High-Temperature Superconducting Ceramics on the Basis of YBa2Cu3O7–δ

Samples of high-temperature superconducting (HTSC) ceramics YBa₂Cu₃O_7– thermally treated in oxidizing and reducing media are investigated by means of the exoelectron emission method. It is found that the thermostimulated exoemission (TSE) increases considerably in the maximum at 470 K after reducing thermal treatment of HTSC ceramics at temperatures of 800–860 K. Correlation dependences between the exoemission activity, the deviation from the stoichiometry in the oxygen sublattice, and the temperature of transition of YBa₂Cu₃O_7– ceramics to the superconducting state are found. These dependences indicate that the exoemission testing can be used in the design of technologies of the synthesis and treatment of HTSC materials on the basis of complex oxides.     

Improving the Accuracy in Determining the Insulator Capacitance in Metal–Insulator–Semiconductor Structures

The results of the voltage–capacitance spectroscopy of interface states in metal–insulator–semiconductor (MIS) structures are critical functions of the accuracy in determining the insulator capacitance C _i, which is typically no higher than a few fractions of a percent. This substantially limits the energy range of the observed spectrum of the interface states (E 0.5 eV for Si-based MIS structures) and the sensitivity to the density of the interface states at the spectrum edges (N _ss 1 × 10¹⁰ cm^–2 eV^–1). We propose a method for minimizing these errors that is based on a sequential variation of the initial estimate C _i C _{i 0} C _ij, j = 0, 1, 2, ... and the identification of singular points in the dependences and on C _ij, where are the mean arithmetic values of the voltage difference between the experimental and ideal voltage–capacitance characteristic and are the rms deviations of the voltage values taken in the high-accumulation (ac) and inversion (in) regions from values. The highest (10^–4%) accuracy in determining C _i is achieved in the regions of the equidistant experimental and ideal voltage–capacitance characteristic. This method, combined with the technique of _s / _s diagrams, ensures an extension of E to 0.9 eV at N _ss 1 × 10¹⁰ cm^–2 eV^–1 and the possibility of determining the sign and density of the fixed charge in the gate insulator.     

Friction coefficient of soft contact lenses: measurements and modeling

Tribological conditions for contact lenses have very low contact pressures in the range 3–5 kPa and sliding speeds around 12 cm/s. Using a microtribometer a series of experiments was run on commercially available contact lenses made from Etafilcon-A. These tests were run using 10–50 mN of normal load at speeds from 63 to 6280 m/s using a 1-mm radius glass sphere as a pin. The resulting contact pressures are believed to be nearly an order of magnitude larger than the targeted 3–5 kPa. It is hypothesized that the viscoelastic nature of the hydrogel, viscous shearing of the packaging solution, and interfacial shear between the glass sphere and the contact lens all contribute to the friction forces. A model that includes all three of these contributors is developed and compared to the experimental data. The experimental friction coefficients vary from = 0.025 to 0.075. The calculated fluid filmthicknesses were between 1 and 30 nm. The average surface roughness of the lens and the glass sphere are R_a=15 nm and R_a=8 nm, respectively, suggesting that the contact is not in full elastohydrodynamic lubrication. Finally, the largest contributors to the friction force in these experiments were found to be viscous dissipation within the hydrogel and interfacial shear within the contact zone.     

Characteristics of InP γ-Detectors

The results of investigations of the characteristics of InP detectors manufactured from a bulk iron-doped material are presented. The characteristics were measured in a temperature range from room temperature to –60°C. At room temperature, at a voltage of 400 V, the back current in the InP detectors was under 10 A. The best spectrometric characteristics of the detectors were obtained at temperatures from –50 to –60°C. The spectra of ²⁴¹Am, ¹⁰⁹Cd, ⁵⁷Co, and ¹³⁷Cs sources recorded with InP detectors are presented.     

Glass–Metal Seals: The Role and Conditions of Metal Annealing before Sealing to Glass

It is generally recommended that the chromium-containing alloy blanks used to produce vacuum-tight glass–metal seals be previously annealed in humid hydrogen. Using the 47 alloy sealed to 95-2 chemical glass as an example, it is shown that annealing of the alloy in humid hydrogen at a temperature of 1050–1100°C leads to formation of a durable oxide film on the surface of the blank. The film is highly wettable with melted glass. Our experiments showed that preliminary annealing can also be performed in an atmosphere of humid argon or helium at a temperature of 1050–1100°C for 1 h. Highly explosive hydrogen can thus be excluded from the production process. The seals obtained by this method are on a par with those produced by the conventional procedure.     

An Automated Installation for Measuring the Complex Thermal Expansion Coefficient of Polymers by the Modulation Dilatometry Technique

An installation designed for measuring the relaxation component of thermal expansion, a typical feature of polymers due to the conformational mechanism of thermal expansion inherent in them, is described. The relaxation component manifests itself as a shift in the expansion variation phase relative to the temperature variations. The installation allows variations of the temperature-oscillation frequency and amplitude in the ranges of 10^–3 to 10^–1 Hz and 1–5 K, respectively. The expansion variation amplitudes were measured using a mechanotron with a sensitivity of at least 10^–2 m. The serviceability of the installation was demonstrated in studies of the thermal expansion of a polymer (polyvinylacetate, PVA). In these studies, a shift in the expansion–temperature phase in the polymer-vitrification region and its dependence on the temperature-oscillation frequency were recorded.     

An Extension of the Conductance-to-Electrical Signal Conversion Range of Capacitance Transducers by Using Self-Excited Oscillators with a Thermistor Bridge

A circuit for the compensation of unbalance is proposed, which allows one to decrease essentially the temperature stability effect on the error and conductance conversion range of a capacitance transducer in self-excited oscillators with a thermistor bridge. The device that converts simultaneously and independently the conductance of the transducer in a range of 10^–6–5 × 10^–3 S with an error of 5% and capacitance in a range of 10^–2–100 pF with an error of 1% into an electric signal is described.     

Accelerator of the НГ-12И neutron generator as an implanter of hydrogen ions

The use of an updated accelerator of the -12 neutron generator as a high-current implanter of hydrogen ions (protons and deuterons) with energies of 175–210 MeV into wafers made of crystalline silicon is described. The ion-beam scanning system used ensured nonuniformity in the irradiation of wafers with a diameter of 100 mm of <10%, which allowed the production of silicon-on-insulator wafers by the hydrogen splitting technique. The required particle fluence was 10¹⁷ cm^–2. A slight refinement of the setup allows wafers with diameters of up to 200 mm to be irradiated. The design features of the setup as they apply to different temperature conditions (down to a temperature close to that of liquid nitrogen) of the irradiation of 100-mm-diameter wafers are described.Translated from Pribory i Tekhnika Eksperimenta, No. 1, 2005, pp. 126–129.Original Russian Text Copyright © 2004 by Stepovik, Mokichev, Magda, Kiryushkin, Kozikov, Semkov, Kurochkin, Lukin, Khmelnitskii, Popov.     

A Magnetometer Based on a Hall-Effect Transducer

An induction meter based on a Hall-effect transducer with in-phase signal suppression and thermostabilization circuits is described. It is powered by a 10³-Hz ac line. The maximum relative error in temperature measurements from 0 to 70°C does not exceed 0.7 % for magnetic fields of 50–100 T, 0.4% for 0.1–1 mT, and 0.1% for 1–625 mT. In the range of 50–500 T, the error is determined by an in-phase signal. The contribution of the total temperature error is 0.01% per 50°C. Depending on the induction of the measured magnetic field, the resolution changes from 0.12 to 19 T.     

A Study of the Electronic Properties of Liquid Argon–Deuteromethane Mixtures

The serviceability of a pulse ionization chamber filled with liquefied argon–deuteromethane mixtures was demonstrated. The substances were purified to a level of 1.7 × 10^–9equiv O₂using a Ni/SiO₂adsorbent. The dependences of the ionization yield from relativistic-electron tracks and the drift velocity of ionization electrons on the electric-field strength were measured in the mixtures with deuteromethane concentrations of 2, 5, 10, and 25%. The properties of liquid CH₄and CD₄were compared. An isotopic effect was observed for the electron-drift velocity.     

Study of the possibility of producing a short acoustic pulse using an inductive-resistive circuit connected to the input of a radiator loaded on a solid through a contact layer

A scheme of radiation is considered that consists of a piezoelectric plate with an RL-circuit connected to its input and that is loaded on a solid through a contact layer. A study of the effect that the systems characteristic parameters have on the duration and amplitude of radiated pulses for different wavelengths thicknesses, specific acoustic impedance of the contact layers, and different acoustic loads is performed on the basis of numerical calculations. Concrete estimates are presented that show the use of the optimal (from the viewpoint of the minimum duration of radiated pulses) characteristic parameters of the system to obtain short acoustic pulses over a rather wide range of the contact-layer wave thicknesses is made possible.Translated from Defektoskopiya, Vol. 40, No. 11, 2004, pp. 15–21.Original Russian Text Copyright © 2004 by Konovalov, Kuzmenko.     

Influence of Radiation on Luminescence Properties of Quartz Glasses and Fibers

The results of an X-ray luminescence investigation of K and K-1 quartz glasses and quartz fibers of variable composition and sizes exposed to X-ray doses of 10²–10⁷ Gy are presented. Two luminescence bands at 410 and 450–470 nm were discovered as a result of an analysis of the X-ray luminescence spectra of glasses and fibers and comparison of the experimental data in glass spectra. The possibility of using the data obtained for quartz glasses for interpretation of the results referring to quartz fibers is considered. The dose dependences of the X-ray luminescence intensities measured for each luminescence band were examined to clear up the nature of the relevant centers. A luminescence band of 410 nm in quartz glasses and fibers is suggested to be due to oxygen-deficient Ge centers damaged during -irradiation, and a 450- to 470-nm band, due to E"-centers, the number of which increases with the absorbed dose. A protective role of OH groups against the generation of luminescent centers induced under the -irradiation of quartz glasses and fibers was confirmed.     

A Temperature Controller with Film Elements

A temperature controller in the range from –20 to +150°C with an error of ±1°C is described. A sensor with a sensitivity of 1 mV/K and a time constant of 5–10 s, based on a Bi–Sb film thermal transducer and a correcting transducer (a wire thermoresistor), is used.     

Development and application of an ultra-precision lathe

This paper deals with the detailed development of an ultraprecision lathe for the purpose of machining magnetic disks. The rotational and feed accuracy and stiffness of the air bearing and the air slide were tested, respectively. A microcutting device using a piezoelectric material was also developed in order to maintain a uniform and precise depth of cut. Experiments machining a magnetic disk were carried out.Nomenclature A [m²] Area of piezoelectric actuator - C _o [mF] Capacitance of PZT - d ₃₃ [m V^–1] Piezoelectric constant - K _f [N V^–1] Equivalent force constant - K _m [N m^–1] Coefficient of force feedback - k _h [N m^–1] Stiffness of hinge - l [m] Length of PZT - M [kg] Mass of PZT system - r [mm] Radius of notch - U [m] Displacement of piezoelectric - ₃ [F m^–1] Dielectric constant of PZT - b [mm] Width of hinge - D _e [N s^–1] Equivalent damping coefficient - F _l [N] External load - K _e [N m^–1] Equivalent stiffness of PZT - k [m² N^–1] Elastic compliance of PZT - L [mm] Distance between hinge holes - M _e [kg] Equivalent mass of PZT - R _o [W] Output impedance of amp. - t [mm] Thickness between hinge holes - V _i [V] Input voltage - [g cm^–3] Density of PZT