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41.
S. K. Patil V. V. Ramakrishna P. K. S. Kartha N. M. Gudi 《Journal of Radioanalytical and Nuclear Chemistry》1980,59(2):331-339
Solutions of HTTA are known to extract tetravalent actinides as M(TTA)4 species. When TOPO is added to HTTA solutions, the extracting of Np(IV) and Pu(IV) from aqueous perchloric acid was enhanced
enormously. The species responsible for the enhanced extraction were identified from the extraction data by the slope ratio
method and JOB's method. It was found that the predominant species responsible for enhancement in the extraction, when [HTTA]≫[TOPO],
was M(TTA)4. TOPO for both Np(IV) and Pu(IV). Furthermore, it was established that depending on the relative concentrations of HTTA and
TOPO, a number of species with the composition M(TTA)a(ClO4)4-a·b TOPO, with a ranging from 1 to 4 and b having values of 1 or 2, are involved in the extraction. Several equilibrium constant
values are given.
Fuel Reprocessing Division. 相似文献
42.
Expulsion of CO2 from the molecular ions of the 2-(2-carboxyphenyl) derivatives of benzoxazole, benzothiazole and benzimidazole gives rise to the base peaks on electron impact. The proposed mechanism for this fragmentation process, involving the anchimeric assistance of the heteroatom by the initial abstraction of the H˙ from the carboxyl group followed by the expulsion of CO2 from the molecular ions, is supported by the study of the linked scan spectra. 相似文献
43.
V. A. Job S. B. Kartha G. Krishnamurty Sheila Gopal 《Analytical and bioanalytical chemistry》1974,269(1):26-28
The fluoride content of aqueous and organic Purex process solutions can be determined with good reproducibility and accuracy. The method includes a distillation separation of fluoride and its subsequent electrometric determination using a fluoride-selective electrode. The analytical range covers 5 to 500 μg of fluoride per aliquot and the concentration limit is 5×10?5 M (1 ppm). Complexing cations like Al(III), Zr(IV), La(III), and U(VI) do not interfere. 相似文献
44.
Nils Bumer Kalathil K. Kartha Stefan Buss Ivn Maisuls Jasnamol P. Palakkal Cristian A. Strassert Gustavo Fernndez 《Chemical science》2021,12(14):5236
Herein, we exploit coordination geometry as a new tool to regulate the non-covalent interactions, photophysical properties and energy landscape of supramolecular polymers. To this end, we have designed two self-assembled Pt(ii) complexes 1 and 2 that feature an identical aromatic surface, but differ in the coordination and molecular geometry (linear vs. V-shaped) as a result of judicious ligand choice (monodentate pyridine vs. bidentate bipyridine). Even though both complexes form cooperative supramolecular polymers in methylcyclohexane, their supramolecular and photophysical behaviour differ significantly: while the high preorganization of the bipyridine-based complex 1 enables an H-type 1D stacking with short Pt⋯Pt contacts via a two-step consecutive process, the existence of increased steric effects for the pyridyl-based derivative 2 hinders the formation of metal–metal contacts and induces a single aggregation process into large bundles of fibers. Ultimately, this fine control of Pt⋯Pt distances leads to tuneable luminescence—red for 1vs. blue for 2, which highlights the relevance of coordination geometry for the development of functional supramolecular materials.In this article, we exploit coordination geometry as a new tool to control the energy landscape and photophysical properties (red vs. blue luminescence) of supramolecular polymers. 相似文献
45.
46.
K. P. R. Kartha Akihiko Kameyama Makoto Kiso Akira Hasegawa 《Journal of carbohydrate chemistry》2013,32(1):145-158
Abstract 2-(Trimethylsilyl)ethyl 2, 3, 6, 2′-tetra-O-acetyl-3′-O-benzyl-6′-O-benzyloxymethyl-β-d-lactoside (9) was synthesized starting from acetobromolactose (1) via 2-(trimethylsilyl)ethyl β-d-lactoside (3). Compound 9 was converted to the trisaccharide derivative 17 after coupling with 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-α-d-galacto-pyranosyl bromide (11). Coupling of 17 with acetobromogalactose (19) gave the tetrasaccharide 20. 相似文献
47.
V. K. Unnikrishnan Kamlesh Alti Rajesh Nayak Rodney Bernard V. B. Kartha C. Santhosh G. P. Gupta B. M. Suri 《Pramana》2010,75(6):1145-1150
It is a well-known fact that laser-induced breakdown spectroscopy (LIBS) has emerged as one of the best analytical techniques
for multi-elemental compositional analysis of samples. We report assembling and optimization of LIBS set up using high resolution
and broad-range echelle spectrograph coupled to an intensified charge coupled device (ICCD) to detect and quantify trace elements
in environmental and clinical samples. Effects of variations of experimental parameters on spectroscopy signals of copper
and brass are reported. Preliminary results of some plasma diagnostic calculations using recorded time-resolved optical emission
signals are also reported for brass samples. 相似文献
48.
Half life for the emission of exotic clusters like 8Be, 12C, 16O, 20Ne, 24Mg and 28Si are computed taking Coulomb and proximity potentials as interacting barrier and many of these are found well within the
present upper limit of measurement. These results lie very close to those values reported by Shanmugam et al using their cubic plus Yukawa plus exponential model (CYEM). It is found that 12C and 16O emissions from 116Ce and 16O from 118Ce are most favorable for measurement (T
1/2<1010 s). Lowest half life time for 16O emission from 116Ce stress the role of doubly magic 100Sn daughter in exotic decay. Geiger-Nuttall plots were studied for different clusters and are found to be linear. Inclusion
of proximity potential will not produce much deviation to linear nature of Geiger-Nuttall plots. It is observed that neutron
excess in the parent nuclei slow down the exotic decay process. These findings support the earlier observations of Gupta and
collaborators using their preformed cluster model (PCM). 相似文献
49.
K. P. R. Kartha F. Dasgupta P. P. Singh H. C. Srivastava 《Journal of carbohydrate chemistry》2013,32(3):437-444
Acetolysis of benzyl ethers of sugars has been carried out with anhydrous ferric chloride in acetic anhydride. By employing this reagent, benzyl ether groups variously placed in sugars or in their glycosides could be removed with ease and replaced by acetyl groups. By controlled acetolysis, preferential removal of certain benzyl groups was possible. The results show that in D-glucose the relative ease of removal of benzyl ether groups by acetolysis follows the order C-6 > C-4 > C-3 > C-2 and that the rate of acetolysis is 6-O-Bn : 3-O-Bn : 2-O-Bn = 125 : 24 : 1. The corresponding methyl ethers were very sluggish towards acetolysis. 相似文献
50.