The constant-volume-velocity nature of hearing aids: conclusions based on computer simulations

In the literature there are several references which imply that various parts of a hearing aid are sources of constant volume velocity. Reported herein are the findings of an investigation of the validity of such statements. A computer scheme, referenced elsewhere, for modeling in situ hearing aids was utilized to test the constant-volume-velocity hypothesis. In particular, capabilities of the receiver, ear hook, and earmold tip to deliver constant volume velocity were investigated via a computer. To facilitate such an investigation, a universal receiver/earmold model was created. This model was broken down into "source" and "load"at three locations: the receive output, output of the ear hook, and medial tip of the earmold. At each location comparisons were made between computed values of source and load impedance. The constant-volume-velocity hypothesis was assumed to be valid for those cases where source impedance was much, much greater than load impedance. Plots of such impedances show that, for the cases investigated, this rarely occurred, except over certain frequency bands. With the exception of in-the-ear hearing aids, these results appear to contradict inferences made in the literature about the constant-volume-velocity nature of hearing aids.     

Joint production of ϕ mesons andπ ±,π 0,p,\bar p,K s 0 andK ± in hadronic interactions

The joint production of ? mesons andπ ^±,π ⁰,p, \(\bar p\) ,K _s ⁰ andK ^± is investigated using a sample of 600,000 inclusive ? meson events obtained in hadron Be interactions with incidentπ ^±,p, \(\bar p\) andK ^± beams. Evidence is presented for the joint production of ? mesons and strange particles produced with non-strange incident beams. With incidentK ^± beam the number of additional strange particles is suppressed. The results are found to be in agreement with the qualitative predictions of a parton fusion model. The comparison with the Lund model for lowp _T processes is fair.     

The problem of radial excitations of light mesons

Strong decays of the ground and radial-excited (L=0) states of light mesons are calculated within a relativistic (Lorentz-contraction-modified) version of the model of spontaneous production of aq \(\bar q\) -pair from vacuum.     

High-p T αα andαp interactions

Properties of secondaries associated with a high-p _T charged trigger particle (3<p _T <5 GeV/c) were studied for αp and αα interactions at c.m. energies \(\sqrt s = 88\) GeV and 125 GeV, respectively. Thep _T distributions of secondaries in the away-jet and trigger-jet regions were compared with those for high-p _{T pp} interactions. No statistically significant differences were seen, except at lowp _T . Momentum and angular distributions of spectator and leading protons were studied as a function of charge and rapidity of the trigger hadron. The observed correlations between trigger charge and number of spectator protons provide evidence of valence quark contributions to the trigger jet.     

Experimental investigation of population inversion of oxygen K-ion levels

Experimental results are reported of investigations of the optical properties of the plasma produced when an AI₂O₃ target is irradiated in vacuum by a high-power neodymiunr-glass laser system. It is shown that a number of 0 VIII and 0 VII ion levels with principal quantum numbers n = 2, 3, 4 are inversely populated. The gain at the wavelength 29 nm (4 3 transition, O VIII) under the experimental conditions is of the order of 0.01 cm^-1. For the heliumlike ions O VII, in a transition with the same principal quantum numbers (ls4p¹P₁ ls3s¹S₀, 36.9 nm), the gain is of the order of 10^-2–10^-1 cm^-1, depending on the electron density.Translated from Lazernye Sistemy, pp. 5–14 1982.     

Electric and tensoelectric study of radiation defects in GaAs

The electric and tensoelectric properties are studied for GaAs crystals which have been irradiated by electrons (2.3 Mev) at 300°K with integrated fluxes of up to 2·10¹⁵ –1·10¹⁹ cm^–2. On the basis of the electrical neutrality equation, including seven energy levels (E1–E5, H0, H1) of the radiation defects, the specific resistivity and the strain sensitivity coefficient are quantitatively analyzed as a function of exposure. The pressure coefficients for the E1–E5 levels with respect to the _c ⁶ point are determined to be (0, 9.6, 11.0, 11.6, 11.6)·10^–6 eV/bar, respectively, at 300°K.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 81–87, October, 1986.     

Geometrical connection between the equations of the special quasiclassical model of atomic systems

We study the geometrical connection between the fundamental equations of the quasiclassical model proposed by Rodimov to explain the behavior of microparticles in atomic systems in his monograph Self-Oscillating Quantum Mechanics; the v and u equations. It is shown that the geometry of the spaces for the v and u equations is different, but the metrical coefficients are related by simple algebraic relations.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 5, pp. 66–70, May, 1986.The author thanks Go I. Flesher for interest in the work and useful critical discussions and also I. L. Bukhbinder for fruitful discussions of the fundamental aspects of the work.     

Determinants and characteristic polynomials

The supersymmetric model in one dimension is used to calculate the fermion and scalar determinants in constant fields and express them in terms of the characteristic polynomials appearing in anomalies and index theorems. The operator determinants are transformed into those of a matrix.     

Parametric Excitation of the Electron-Acoustic Wave in a Multiply Ionized Plasma

Parametric excitation of the electron-acoustic wave (EAW) has been analysed using a hydrodynamical model. The plasma has been assumed to consist of multiply charged ions. The ratio (α) of the hotter ion concentration to that of the electrons is a sensitive parameter. The condition for the occurrence of the EAW is well satisfied for the smaller values of α. The growth rate of the instability gets enhanced by increasing α and the charge state of the hotter ions. The values of α can be varied within short range only.