Role of the middle ear muscle apparatus in mechanisms of speech signal discrimination

A method of impedance reflexometry was used to examine 101 students with hearing impairment in order to clarify the interrelation between speech discrimination and the state of the middle ear muscles. Ability to discriminate speech signals depends to some extent on the functional state of intraaural muscles. Speech discrimination was greatly impaired in the absence of stapedial muscle acoustic reflex, in the presence of low thresholds of stimulation and in very small values of reflex amplitude increase. Discrimination was not impeded in positive AR, high values of relative thresholds and normal increase of reflex amplitude in response to speech signals with augmenting intensity

Temperature dependence of contact resistance of Au-Ti-Pd2Si-n+-Si ohmic contacts

We investigated temperature dependence of contact resistance of an Au-Ti-Pd2Si ohmic contact to heavily doped n+-Si. The contact resistance increases with temperature owing to conduction through the metal shunts. In this case, the limiting process is diffusion input of electrons to the metal shunts. The proposed mechanism of contact resistance formation seems to realize also in the case of wide-gap semiconductors with high concentration of surface states and dislocation density in the contact

A specialized isotope mass spectrometer for noninvasive diagnostics of Helicobacter pylori infection in human beings

A specialized isotope mass spectrometer for noninvasive diagnostics of Helicobacter pylori infection in human beings based on the carbon-13 isotope breath test has been designed and constructed. Important stages of the work included (i) calculating a low-aberration mass analyzer, (ii) manufacturing and testing special gas inlet system, and (iii) creating a small-size collector of ions. The proposed instrument ensures 13C/12C isotopic ratio measurement to within 1.7‰ (pro mille) accuracy, which corresponds to requirements for a diagnostic tool. Preliminary medical testing showed that the mass spectrometer is applicable to practical diagnostics. The instrument is also capable of measuring isotopic ratios of other light elements, including N, O, B (for BF2+ ions), Ar, Cl, and

УДОСКОНАЛЕННЯ МЕТОДУ ОЦІНЮВАННЯ НАДІЙНОСТІ СХЕМ РЕЛЕЙНОГО ЗАХИСТУ

In paper the fault tree method for the relay protection scheme reliability estimation at the time interval is improved. The improved method can be used as input information of the following values: the averaged reliability indexes of equipment, the statistical functions of relay scheme elements of fault probability distribution and the modified statistical functions of relay scheme elements of fault probability distribution. The improved fault tree method is possible to apply both for the comparison estimations and for the risk-management problem solution. In practical part of the paper the comparison of reliability analysis of relay schemes with electromechanical relays and digital relays is presented. The obtained results show that the reliability of modern digital relay schemes is less than the reliability of electromechanical relay schemes. Also, in paper the quantity estimation of 6 kV network current protection fault probability is obtained by using the statistical functions F(t)Усовершенствован метод дерева отказов для оценивания вероятности отказа схемы релейной защиты на интервале времени путем использования статистических функций распределения вероятности отказов элементов схемы релейной защиты. Усовершенствованный метод позволяет проводить оценку надежности схем релейной защиты с учетом характеристик отдельных типов оборудования. Проведен сравнительный анализ надежности схем релейной защиты на электромеханической и микропроцессорной элементных базахУдосконалено метод дерева відмов для оцінювання імовірності відмови схеми релейного захисту на інтервалі часу шляхом використання статистичних функцій розподілу імовірності відмов елементів схеми релейного захисту. Удосконалений метод дозволяє проводити оцінку надійності схем релейного захисту з урахуванням характеристик окремих типів обладнання. Проведено порівняльний аналіз надійності схем релейного захисту на електромеханічній та мікропроцесорній елементній базах

A Novel Mechanism for Ensuring the Ohmicity of Contacts to n-InP & n-GaAsover a Wide Range of Temperatures down to Helium One: Experiment and Theory

At present two physical mechanisms that ensure realization of ohmic contacts to semiconductorsare known [1S.M.Sze]. These are: 1) field emission in presence of a doping step that leads toformation of a strongly degenerate layer in the near-contact semiconductor region and 2) thecase of Schottky contacts with low barrier height, below 25 mV.Here we present the results of investigation of temperature dependence of contact resistivity forn-InP- and n-GaAs-based contacts with high dislocation density, performed over a wide range oftemperatures down to helium one. We revealed that the above contacts are ohmic over the wholetemperature range. The results obtained are explained using a novel mechanism of current flow inmetal-semiconductor contacts that differs from those described in [1]. A new mechanism isrelated to the current flow through nano-sized metal shunts associated with dislocations. Becauseof very strong electric fields appearing at the shunt ends adjacent to semiconductor, a highmirror-image potential is realized that reverses sign of band bending in the semiconductor regionsadjacent to the metal shunts. As a result, accumulation band bending is realized in those regions,and the contacts remain ohmic at any temperature.The experimental temperature dependence of contact resistivity curves are nonmonotonic andare in good quantitative agreement with those described theoretically using a new mechanism ofcurrent flow with additional allowance for electron freeze-out at low temperatures