Perturbed angular correlation study of radiation-induced defects in Rh metal

Radiation-induced defects are studied in cubic rhodium metal, using the local probe technique ‘Time differential perturbed angular correlation’ (TDPAC) at liquid N₂ temperature. Isochronal annealing was done at 300, 1073 and 1473 K temperatures. The irradiated sample showed two quadrupole interaction frequencies at 1150 and 93 MHz. The low frequency disappeared at room-temperature annealing, which was assigned to In trapped at a vacancy, whereas the higher frequency remained up to high temperatures and was attributed to In trapped at Rh–C complexes in the Rh matrix.     

Mössbauer Study of Magnetic FeSb Dilute System

Hyperfine Interactions - Mössbauer study of semimetals is of great importance in understanding the origin of hyperfine interactions in these materials. A concentration dependence study in Fe x...     

Mössbauer Study of Multiple Substitutions in YBCO

Hyperfine Interactions - Mössbauer studies of multiple substitutions in YBCO with general formula (Y1?Z Ca Z )Ba2(Cu1?X?Y Fe Y M X )3O7?δ are reported. XRD has...     

Cosmic ray produced silicon-32 in near-coastal waters

The specific activity of Silicon-32 is measured is near-coastal seawaters using anin situ method for the extraction of dissolved silica. The results are discussed in relation to the input of Si³² at the surfacevia rains, the expected variation in its concentrations due to continental run-off and influx of open ocean surface waters. The experimental results clearly demonstrate the usefulness of Si³² as a tracer for the study of the vertical structure of the ocean in the upper layers, and of seasonal variations in the types of waters entering in the coastal regions.     

Concentration Dependence of Room Temperature Magnetic Ordering in Dilute Fe: Ge1 − x Te x Alloy

Hyperfine interaction techniques like Mossbauer spectroscopy are very sensitive tools to study the local probe interactions in dilute magnetic semiconductors. We report here a Mossbauer study on the concentration dependence in Fe_0.008Ge_{1 − x} Te _x for x = 0, 0.008, 0.016, 0.03 and 0.05. At room temperature magnetic interactions were observed for all concentrations of Te and the population of magnetic site was found to increase gradually with the Te concentration. A constant magnetic hyperfine field of 136 KOe was found. A quadrupole doublet due to the FeTe₂ compound phase was also seen.     

Synthesis of some chromono (7, 8) oxazoles and their antibacterial activity

The synthesis of a few 2-substituted aryl-8-methyl-chromono (7, 8) oxazoles is described. A study of the antibacterial activities of these compounds has revealed that 2-(p-nitrophenyl) 8-methyl-chromono (7, 8) oxazole is active in 1 in 10,000 parts concentration.     

U234/U238 activity ratios in South Pacific Ocean waters

Analyses of uranium extracted from South Pacific waters by thein-situ extraction method point to a uniform depth independent value of 1·14 ±0 02 for the U²³⁴/U²³⁸ activity ratio. This value is also the same, within one standard deviation, as that determined for the N. Pacific, S. Indian and Atlantic waters.     

Two new 5-deoxyflavonoids from Calliandra inermis

Two new 5-deoxyflavonoids, 7,2',3',4'-tetramethoxyflavone (1) and 7,2',3',4'-tetramethoxyflavanone (2) together with a known flavone 7,4'-dimethoxy-3'-hydroxyflavone (3) were isolated from the whole plant of Calliandra inermis. The structures of these new compounds were elucidated by high resolution electron impact mass spectrometry (HR-EI-MS) and 1D and 2D-NMR spectral studies including 1H-1H correlation spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond connectivity (HMBC) and nuclear Overhauser enhancement spectroscopy (NOESY).     

Characterisation of nuclear fuel by spectroscopic evaluation of alpha autoradiographs

New methods for estimation of concentration and distribution of plutonium in (Th,Pu)O₂ MOX fuel samples have been attempted by spectroscopic analysis of SSNTD based alpha images using UV–Vis spectrophotometry and photoluminescence spectroscopy. (Th,Pu)O₂ MOX fuel samples having a large range of PuO₂ concentration, were subjected to this study and found beneficial when compared with the conventional analysis of alpha autoradiographs. UV–Vis absorbance and photoluminescence of the alpha autoradiograph showed linear decrease proportionally to PuO₂% in the fuel sample. Optical band gap was found to proportionally increase with PuO₂% in the fuel sample which was revealed in UV–Vis spectrophotometry.