An Entire Function Defined by a Nonlinear Recurrence Relation

For the nonlinear recurrence relation it is proved that the limit exists and defines an entire function of ₂ = ₁(1-₁).     

Improved equivalent circuits for acoustic plate wave devices

This paper presents improved equivalent circuits for the analysis and design of acoustic plate wave devices. The method uses a mixed equivalent circuit for the interdigital transducer consisting of both active and passive sections placed on the surface of a piezoelectric plate. The values of the various circuit elements are obtained by carrying out a best fit between theoretical and experimental frequency dependence of the real and imaginary parts of transducer input impedance. Knowledge of the equivalent circuit parameters allows one to optimize design of the devices. The method has been successfully employed for the design of one-port shear-horizontal wave resonators on Y-X lithium niobate plates. The proposed method can also be utilized for determining acoustic wave velocity with high accuracy.     

Reflection of normal acoustic waves in thin plates from a grating with a periodically distributed mechanical load

Reflection of zero-order normal acoustic waves excited in a thin piezoelectric plate from a set of conducting strips of a finite thickness is studied both theoretically and experimentally. The analysis shows that the effects produced by the short-circuiting of the plate surface and by the elastic load on the impedance ratio of adjacent plate segments are in opposition to each other. These effects can be commensurable, and, hence, for each wave type, there is a certain value of the strip thickness at which the reflection coefficient becomes equal to zero. The experimental results obtained for a shear horizontal normal wave (an SH ₀ wave) propagating in a lithium niobate plate are in good agreement with the theory and justify the use of the equivalent-circuit model in analyzing the properties of reflectors of the type under study.     

The third and fourth spectra of gallium: Ga III and Ga IV

The third and fourth spectra of gallium have been photographed in the region 6000–400 Å by using a 3-m normal-incidence, vacuum spectrograph and a 3.5-m Ebert spectrograph. A three-electrode vacuum spark and a spark in helium were used as sources. New measurements for the wavelengths have confirmed earlier work and provided material to extend the analysis of Ga III and Ga IV.     

Visible green emission of Ho3+ and Er3+ in tellurite glass

Characteristic visible green emission of Ho³⁺ and Er³⁺ was observed in zinc tellurite glass. Multiphonon relaxation theory was quantitatively applied to explain the experimentally obtained results. Fluorescence assignments and lifetime measurements have also been made.     

Study of the traps created in the single crystal of CdSe by the irradiation of Mo K α X-ray quantum

Traps were created in the single crystal of CdSe by bombardment with Mo Kα X-ray radiation. These traps were studied by the relaxation curves of photoconductivity, obtained at 6000 Å and after two dosages of radiation. It has been found out that the traps created were β-type.     

Thermodynamic properties of some monomeric compounds in the standard ideal gas state

Thermodynamic functions of ten monomeric compounds have been calculated for three temperatures by the statistical method using molecular structural data and vibrational assignments. The ideal gas state entropies at 298.15°K are: maleic anhydride, 71.9; β-propiolactone, 69.1; vinylene carbonate, 70.1; cyclopentadiene, 65.3; diketene, 72.3; cyclopropene, 58.7, vinyl fluoride, 60.4; ethyleneimine, 62.8; butatriene, 71.7; and carbon suboxide, 66.0 cal./deg-mole. The standard free energies and equilibrium constants of formation are also derived by using mostly the published data on the heats of formation of these monomers.     

The integral mean diffusivity for particle-gas mass transfer calculations under thermal plasma conditions

Plasma Chemistry and Plasma Processing - A new integral mean diffusivity is proposed for the calculation of the mass transfer rate around a small particle immersed in a thermal plasma gas....     

Electrothermal AAS studies of Sm, Eu, Dy, and Er separated from uranium

Summary Studies were conducted on the assay of Sm, Eu, Dy and Er separated from uranium using aqueous standards by electrothermal AAS with Massmann type graphite furnace. The working curves were found to be linear in the ranges Sm (1–10 g/ml), Eu (0.05–0.6 g/ml), Dy (0.1–0.8 g/ml) and Er (0.1–1.0 g/ml). The values obtained for synthetic samples agreed favourably with those obtained by emission spectrographic method. Experiments using pyrolytic carbon coated tubes with and without pretreatment by La, Ta and Y have shown an enhancement with treatment upto a maximum of 15% and improve the memory effect marginally. The effect of Ta treatment was found to be singularly useful in improving the general behaviour of Sm. The interference effects of lanthanides, other than the analyte, were found to be negligible. However, the presence of uranium was found to affect the absorbance. The absorbance of Eu was found to be nearly independent of uranium after an initial increase. On the other hand, the absorbance of other elements studied was found to drastically decrease after an initial enhancement. Detailed investigations of temperature dependence of absorbance were carried out using Eu, Dy and Er. The differences in the behaviour of these elements is attributed to probable differences in the modes of their atomization.

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Untersuchung von aus Uran abgetrenntem Samarium, Europium, Dysprosium und Erbium durch elektrothermische Atomabsorptions-Spektralphotometrie

Zusammenfassung Die Untersuchungen wurden mit Hilfe des Graphitrohrofens nach Maßmann durchgeführt. In folgenden Bereichen ergaben sich lineare Eichkurven: Sm 1–10 g/ml, Eu 0,05–0,6 g/ml, Dy 0,1–0,8 g/ml, Er 0,1-1,0 g/ml. Die aus synthetischen Proben erhaltenen Ergebnisse stimmten gut mit den durch Emissionsspektrographie erhaltenen überein. Versuche wurden mit Röhren mit pyrolytischen Kohlenstoffüberzug mit und ohne Vorbehandlung durch La, Ta und Y durchgeführt und ergaben eine bis 15%ige Steigerung durch die Behandlung sowie eine mäßige Besserung des Memoryeffektes. Eine Behandlung mit Ta war besonders für Sm vorteilhaft. Störungen durch andere Lanthanide waren vernachlässigbar. Uran beeinflußte jedoch die Absorption. Im Falle von Eu zeigte sich nach anfänglicher Zunahme fast eine Unabhängigkeit, während bei den anderen untersuchten Elementen nach anfänglicher Zunahme eine beträchtliche Abnahme auftrat. Mit Eu, Dy und Er wurde ebenfalls die Temperaturabhängigkeit der Absorption untersucht. Festgestellte Unterschiede im Verhalten werden auf unterschiedliche Atomisierung zurückgeführt.