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71.
P. Govindan A. Palamalai K. S. Vijayan M. Raja S. Parthasarathy S. V. Mohan R. V. Subba Rao 《Journal of Radioanalytical and Nuclear Chemistry》2000,246(2):441-444
A two step precipitation using ammonium carbonate and oxalic acid as the precipitants for thorium and iron is developed for the purification of 233U. Ammonium carbonate is added to the feed to increase the pH of the solution. The effect of pH on the solubility of U, Th and Fe in an excess of ammonium carbonate is studied. This indicates that the solubility of Th and Fe is minimum at pH 7 and the recovery of uranium is maximum. The effect of the concentration of thorium and iron on the recovery of uranium at pH 7 is studied. This indicates that the ammonium carbonate precipitation tolerates 2 g/l of thorium and 10 g/l of iron keeping losses of uranium to a minimum. If the feed solution contains more than a tolerable concentration of thorium the precipitation is followed in two steps: (1) Bulk of the thorium is removed by oxalate precipitation, (2) the remaining thorium and iron in the supernatant are removed by ammonium carbonate precipitation. A flow sheet is proposed for the purification of 233U from thorium and iron present in a strip product concentrate obtained during the reprocessing of irradiated thorium rods. 相似文献
72.
Theoretical expressions for the overall values of three Booth type R-indices based on intensity variables are derived. The
results are applicable to crystals of any space group containing any number and type of atoms at general positions in the
asymmetric unit. The theoretical results were tested in the case of models of a few crystal structures. 相似文献
73.
P. Parthasarathy H. B. Desai S. R. Kayasth 《Journal of Radioanalytical and Nuclear Chemistry》1986,105(5):277-289
Radiochemical neutron activation analysis /RNAA/ has been applied for the determination of individual rare earth elements /REE/, except Tm, in 8 Indian monazites and one each from Malaysia and Thailand. Because of the very low amounts of heavy rare earths /HREE/ compared to light rare earths /LREE/ in monazite, HREE from Ho onwards have been determined only after the separation of the heavy and light rare earth fractions in the irradiated monazite samples. The results indicate significant variations in REE contents from Eu to Lu among different monazite samples. The chondritic normalized REE patterns of all the samples show a prominent negative Eu anomaly with different slopes at the heavy rare earth end. All the individual REE, except Tm, have been reported for the first time in various Indian monazites. 相似文献
74.
75.
76.
Rahul Basu R. Parthasarathy 《The European Physical Journal C - Particles and Fields》1998,4(4):679-683
A mechanism for instanton induced chiral symmetry breaking in an extended QCD model (QCD with fundamental scalars) is proposed
to describe quarks and gluons inside a baryon. The model Lagrangian that we use has the same symmetry properties as QCD. The
scalar fields are shown to develop vacuum expectation values in the instanton background and generate masses for the three
generation of quarks. The minimization condition is also used to break the flavour symmetry to make the -quark heavier that the and quarks.
Received: 16 August 1996 / Revised version: 15 October 1997 / Published online: 26 February 1998 相似文献
77.
An upper bound for the number of lines in a geodetic block of diameter d on p points is obtained, using some new general properties of geodetic blocks which are also of independent interest. 相似文献
78.
Some ot the factors governing the response time of the fluoride-selective and chloride-selective electrodes have been investigated. The results of E—t and conductance measurements indicate that dissolution and charge-transfer processes control the ion-seiective electrode kinetics. The temperature coefficients of the rate constants for dissolution of the chloride electrode membrane, determined by E—t curves and conductimetric measurements, are similar. The results, and the fact that the dissolution is a second-order process, indicate that surface processes play the predominant role in electrode kinetics near equilibrium. 相似文献
79.
A. K. Nayak S. K. Sarkar R. S. Karve V. Parthasarathy K. V. S. Rama Rao J. P. Mittal S. L. N. G. Krishnamachari T. V. Venkitachalam 《Applied physics. B, Lasers and optics》1989,48(5):437-443
Infrared laser multiple photon excitation/dissociation of Thiophene (Th) was studied as a function of Th pressure, laser pulse energy, pulse duration and added buffer gas. While the excitation process was probed via optoacoustic technique, the stable reaction products were analyzed by IR spectroscopy and mass spectrometry. Although C2H2 and CH3CCH were the major hydrocarbon products under all experimental conditions, the distribution of these, as well as higher hydrocarbons of lower yield, was found to be very much dependent upon the experimental conditions. The laser induced reaction under dielectric breakdown conditions with either high substrate pressure or laser energy produced significant amount of CS2 and unidentified polymer as well. We propose a mechanism involving breakage of the C–S bond in Th to form an unstable 1,5-diradical which further decomposed via different channels. However, at higher substrate pressures, radical-Th reactions complicated the overall chemistry of the system. Evidences for collisional energy-pooling and rotational hole-filling were also obtained. 相似文献
80.
V. Parthasarathy S. K. Sarkar K. V. S. Rama Rao J. P. Mittal 《Applied physics. B, Lasers and optics》1986,39(3):187-190
Selective decomposition of CDF3 at natural abundance level (150ppm) in fluoroform has been achieved by infra-red multiple-photon excitation at moderate substrate pressure using 100 ns FWHM CO2 laser pulses. Effects of energy fluence, number of laser pulses, buffer gas pressure and substrate pressure on decomposition yield and bulk selectivity are reported and discussed. 相似文献