Isomeric transitions in203Bi and205Bi

High spin states in^{203, 205}Bi, populated in the^{203, 205}Tl (α,4n) reactions, have been studied using gamma-ray and conversion-electron spectroscopy. Several previously unobserved isomeric transitions were identified by electron-electron coincidence measurements in both isotopes and in²⁰⁵Bi a new isomer was found. The observed states can be explained as arising from couplings of the oddh _9/2 proton to neutron states in the neighbouring Pb cores. Reduced transition probabilities are derived and discussed.     

On discrete boundary value problems arising in transport phenomena

For the discrete boundary value problems arising in transport processes we provide comparison results. These results are used to develop monotone iterative methods for the construction of the maximal and minimal solutions in a sector. The advantage of this technique is that the successive approximations are the solutions of the initial and terminal value problems. Numerical illustration showing the sharpness as well the importance of the obtained results is also included.     

Infinite Interval Problems Modeling the Flow of a Gas Through a Semi-Infinite Porous Medium

Various existence results are presented for boundary-value problems on the infinite interval. In particular, our theory includes a discussion of a problem arising in the unsteady flow of a gas through a semi–infinite porous medium.     

Model equations from a chaotic time series

We present a method for obtaining a set of dynamical equations for a system that exhibits a chaotic time series. The time series data is first embedded in an appropriate phase space by using the improved time delay technique of Broomhead and King (1986). Next, assuming that the flow in this space is governed by a set of coupled first order nonlinear ordinary differential equations, a least squares fitting method is employed to derive values for the various unknown coefficients. The ability of the resulting model equations to reproduce global properties like the geometry of the attractor and Lyapunov exponents is demonstrated by treating the numerical solution of a single variable of the Lorenz and Rossler systems in the chaotic regime as the test time series. The equations are found to provide good short term prediction (a few cycle times) but display large errors over large prediction time. The source of this shortcoming and some possible improvements are discussed.     

Radiation guiding in a plasma wave wiggler free-electron laser

The radiation guiding of a plasma wave wiggler free-electron laser (FEL) in the Compton regime was examined. It was found that a Langmuir wave supported by a plasma cylinder acts as a wiggler for the generation of high-frequency coherent radiation when an annular relativistic electron beam passes through it. The radiation mode in the Compton regime tends to be localized close to the radius of the beam. A normal-mode analysis of this process revealed that the growth rate of the instability increases as the square root of the beam current. The treatment presented is restricted to the case where the radial width of the FEL radiation mode is larger than the beam radius, but smaller than the waveguide radius     

Analysis of propagation in a SELFOC fibre: The axial field component and the effect of multiple reflections

Based on the WKB solution of the wave equation, a discussion of the polarization rotation of Gaussian beams in focusing fibres is given. Near the focusing region the change of polarization has been found to be appreciable. The finite longitudinal size of fibres has been found to reduce the effective length of samples for wave focusing.     

Influence of dye-indicators on transfer coefficient of electrode processes

Summary The addition of indicator increases the transfer coefficient of ferrous-ferric reaction (containing. 002 M equi molecular concentration), showing thereby that the indicator gets preferentially adsorbed at the electrode solution interface during the anodic half wave. The transfer coefficient is not being affected with the variation in concentration of the indicator. The extent of increase in transfer coefficient varies in the following order: bromo-thymol blue methyl red bromocresol purple or thymol blue. In presence of bromo-thymol blue, methyl red and thymol-blue as well as bromo-cresol purple, the transfer coefficients are. 669,. 663 and. 643 respectively at 30 ‡C.

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Zusammenfassung Die Zufügung von Indikatoren erh?ht den Transferkoeffizienten der Ferro-Ferri-Reaktion (bei 0,002 M ?quimolekularer Konzentration), wobei sich zeigt, da\ der Indikator bevorzugt an der Oberfl?che: Elektrode/ L?sung w?hrend der anodischen Halbwelle adsorbiert wird. Der Transferkoeffizient wird durch Konzentrations?nderungen des Indikators nicht beeinflu\t. Das Ausma\ seines Anstiegs variiert in folgender Ordnung: Bromthymolblau, Methylrot, Bromkresolpurpur oder Thymolblau. Die entsprechenden Transferkoeffizienten nach obiger Reihenfolge sind bei 30 ‡C:0,669, 0,663 und 0,643.

     

Application of the three body force shell model to the lattice dynamics of calcium oxide

The lattice dynamics of GaO has been studied on the basis of the three body force shell model, which takes into account the effect of many body interactions in the lattice potential. The dispersion curves obtained by plottingω vsq agree fairly well with the experiments. It is concluded that the value of the molecular electronic polarizability of the solid must be must small than that determined experimentally which suggests that the interaction system in the solid may have a substantial covalent character.