A finite-element method for creep calculations on structures

A form of the initial-strain method is proposed that implements a general equation of state for a material during creep. A noniterative exact method has been devised for incorporating the effects of temperature on the elastic properties in a finite-element calculation.Translated from Problemy Prochnosti, No. 4, pp. 8–13, April, 1992.     

Thermal field created by an irradiator with a slot capacitance studied on tissue-equivalent phantoms

Experiments were carried out on phantoms imitating muscular and fatty tissues which were exposed to a single action of microwave hyperthermia in microwave set "Volna-2" (460 MHz installation with a modified antenna. The temperature in the phantoms was measured by copper-constant thermocouples in periods of automatic switching off the microwave power. Temperature distribution in the phantoms was found to depend on the depth, exposure time and power.     

Formation of Planar Field-Emission Devices Based on Carbon Nanotubes on Co–Nb–N–(O) Alloy

Semiconductors - Integrated field-emission devices and integrated circuits (ICs) based on them are a promising direction in microelectronics, which is associated with the use of low-voltage and...     

Annealing effect on the formation of high-k dielectric in the W/ultrathin HfO2/Si-substrate system

Using a method of high-frequency magnetron sputtering, the structures W(150 nm)/HfO₂(5 nm)/Si(100) were prepared and were further annealed either at 500°C in vacuum for 30 min or in an atmosphere of argon at 950°C for 12 s. Study of the capacitance-voltage characteristics of these structures showed that high-temperature annealing leads to a decrease in the maximum specific capacitance in accumulation (from 4.8 × 10^?6 to 3.2 × 10^?6 F/cm²) and dielectric constant (from 27 to 23). Using time-of-flight secondary-ion mass spectrometry, it is established that growth of a WO _x phase at the W/HfO₂ interface and a HfSi _x O _y silicate phase at the HfO₂/Si (100) interface occurs during annealing. In addition, the total thickness of the intermediate oxide layer exceeds the thickness of the initial HfO₂ film by 30%.     

Influence of optical properties of the SOI structure on the wafer temperature during rapid thermal annealing

Optical characteristics are compared theoretically, and temperature differences of the Si wafer with the B-doped SOI structure and substrate wafer are evaluated during rapid thermal annealing. It is shown that under identical annealing conditions and temperatures above 800 K, the difference in their temperatures can reach ∼30 K. We studied the dependence of the total emissivity and temperature of the wafer with the SOI structure on the concentration of the doping impurity in the Si layer. The method of the quantitative analysis of variations of the wafer temperature under invariable annealing conditions depending on the variations of emissivity of its surfaces is suggested.     

The Coaxial Shunt for Measurement of Current Pulses of Artificial Lightning with the Amplitude up to ±220 kA

The improved construction of the coaxial shunt SC-300M intended for measurement of decaying sine and aperiodic pulses of artificial lightning current with amplitudes up to ±220 kA is described. The results of tests of the instrument shunt in the high-current discharging circuit of power high-voltage generator of lightning current (g.l.c.) under pulsed A-component with the first amplitude -198 kA corresponding to time ≈35 µs and an action integral of the simulated pulse of current of lightning discharge equal to ≈2.38 × 10⁶ J/Ω are presented. The quantity of electricity under single action on the shunt by a current pulse of artificial lightning with logarithmic decrement of oscillations ≈2.06 that passed through the current-carrying elements of its construction was ≈-9.9 C. It was shown that, simultaneously with registration of pulsed A-component of lightning current, the shunt, owing to using of a matching voltage divider at the end of its cable communication line, allows also to measure normalized amplitude-time parameters of aperiodic shortened long-term C*-component of artificial lightning current (-568 A; ≈5 ms;τ_C* ≈18 ms; -16 C) that was being formed in the discharging circuit of the generator.     

Use of Partially Thermally Coupled Distillation Systems and Heat Pumps for Reducing the Energy Consumption in the Extractive Distillation of an Isobutanol–Isobutyl Acetate Mixture Using Dimethylformamide

Theoretical Foundations of Chemical Engineering - The extractive distillation of an isobutanol–isobutyl acetate mixture using dimethylformamide has been considered. Schemes that use vapor...