Simultaneous K plus L shell ionized atoms during heavy-ion collision process

The fraction of simultaneous K plus L shell ionized atoms is estimated in Fe, Co and Cu elements using carbon ions at different projectile energies. The present results indicate that the fraction of simultaneous K plus L shell ionization probability decreases with increase in projectile energy as well as with increase in the atomic number of the targets atoms.     

On the suitability of Peltier cooled Si-PIN detectors in transmission experiments

The performance of a Peltier cooled Si-PIN detector is compared with that for a Freolectric cooled Si(Li) detector, references being made to transmission experiments that evaluate total cross sections at low photon energies. The results of these measurements are discussed.     

Crystallization kinetics study on higher homologues of benzylidene aniline compounds: impact of phase variant on nucleation process

A systematic kinetic study leading to the crystallization process from the kinetophases (which occur prior to crystal phase) smectic B, crystal G and smectic F is performed on representative compounds of the homologous series p-phenylbenzylidene-p'-alkylanilines (PBnA) and p-n-alkoxybenzylidene-p'-alkylanilines (nO.m) these compounds are p-phenylbenzylidene-p'-nonylaniline (PB9A), p-phenylbenzylidene-p'-tetradecylaniline (PB14A), p-n-pentadecyloxybenzylidene p'-tetradecylaniline (15O.14) and p-n-octadecyloxybenzylidene-p'-nonylaniline (18O.9). The molecular mechanism and dimensionality in crystal growth from the kineto phases are computed from the Avrami equation, while the characteristic crystalline time (t*) at each crystallization temperature is deduced from the individual plots of log t vs. ΔH. The low magnitudes of the dimensionality parameter n infers the occurrence of diffusion-controlled transformations leading to the formation of plates or needles of finite size possessing impinged edges. The degree of variation in the value of n at each crystallization temperature also reveals the existence of an independent nucleation mechanism for any individual member of the series. The influence of the terminal alkyl chain lengths on the rate of crystallization is determined from a comparative study with the reported analogous compounds.     

Determination of phosphorous in titanium bearing minerals by potentiometric titration using Pb-ion selective electrode

A method for phosphorous determination in titanium bearing minerals by potentiometric titration using a Pb-ion selective electrode has been developed. Sample decomposition is achieved by means of K(2)CO(3) fusion in a platinum crucible at 800 degrees C for 30 min in a muffle furnace, and subsequent leaching with water of the fused melt. The aqueous leachate is neutralised with HClO(4) and subsequent boiling. The obtained solution is used for titration with Pb(ClO(4))(2), and the Pb-ion selective electrode detects the end point. The lowest concentration determinable is 0.02% P(2)O(5) in a solid sample. The method was applied on in-house titanium bearing mineral samples and on IGS-31 ilmenite sample (British Geological Survey, UK). Synthetic samples were prepared and analysed, and phosphorous recovery is in the range 98-106%. The recovery and accuracy of the present method have been validated by spiking experiments and by comparing with the spectrophotometric values, respectively. The precision of the proposed method in terms of relative standard deviation is 2.0%.     

On the supersingular reduction of elliptic curves

Let a∈Q and denote byE _a the curvey ² = (x ² + l)(x + a). We prove thatE _a(F_p) is cyclic for infinitely many primesp. This fact was known previously only under the assumption of the generalized Riemann hypothesis. Research partially supported by NSERC grant A9418.     

Electron Capture Probabilities in105Ag

TheK-electron capture probabilities for the 1/2^? → 3/2^? and 1/2^? → 1/2⁺ transitions in the decay of¹⁰⁵Ag were measured for the first time using the sum coincidence method. The experimental P_K values were estimated to be 0.824 ± 0.042 and 0.851 ±0.046 for the allowed and first-forbidden beta transitions, respectively in agreement with the theory. The P_L experimental values to these two levels were also computed using the experimental P_L/P_K values reported by earlier authors. These results are also found to be consistent with the theoretical P_L values.