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121.
Alkyl, aryl and cyclic sulfides are rapidly oxidized to the corresponding sulfoxides in high yields upon microwave thermolysis with iron(III) nitrate impregnated on clay (clayfen) under solvent-free conditions; the conversion also occurs in refluxing methylene chloride but requires much longer reaction time. 相似文献
122.
Bio-inspired sustainable synthesis of silver chloride nanoparticles and their prominent applications
Yuvraj Kashid Suresh Ghotekar Muhammad Bilal Shreyas Pansambal Rajeshwari Oza Rajender S. Varma Van-Huy Nguyen H.C. Ananda Murthy Dhananjay Mane 《印度化学会志》2022,99(5):100335
Advanced nanotechnology is an enormously growing area due to its massive scope of applications for diverse domains of applied science and engineering. Numerous types of synthetic procedures are utilized for the creation of nanoparticles (NPs) due to their myriad application scenarios. However, known conventional physical and chemical strategies have a number of shortcomings. Consequently, the designs of facile, clean, safer, non-noxious, reliable, inexpensive and eco-friendly processes for manufacturing of NPs are being explored actively to circumvent these barriers. The phytogenic fabrication of NPs is much safer, one-pot, facile, and a sustainable methodology. Hence, divergent biological means like the use of plants, biopolymers, fungi, fibres, bacteria, enzymes, etc., are pursued the procurable biogenic fabrication of metallic NPs. In this review paper, current findings on the bio-inspired fabrication of silver chloride nanoparticles (AgCl-NPs) are deliberated, which have with their useful appliances in assorted sectors. The experimental protocols, advanced characterization techniques along with diverse applications of biogenically synthesized AgCl-NPs have been highlighted. 相似文献
123.
M. Ravikumar M. Satish Varma T. Satyanarayana Raju P. Suchitra P. Yadagiri Swamy 《Chromatographia》2009,69(1-2):85-89
A new stereospecific LC method for the separation and quantification of moxifloxacin and its (R,R)-enantiomer in bulk drug was developed and validated by ligand-exchange liquid chromatography on a reversed phase column using aqueous mobile phase containing the chiral reagent l-isoleucine-Cu(II). The UV detector was operated at 293 nm. The flow rate of mobile phase was set at 0.9 mL min?1. The achiral ODS column offers good separation of the two enantiomers in less than 20 min. The test concentration was 1,000 μg mL?1 in the mobile phase. This method was capable of detecting the (R,R)-enantiomer of moxifloxacin up to 0.1 μg mL?1 for a 20 μL injection volume. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. There was no interference of degradants with the (R,R)-enantiomer in the developed method. The developed chiral RP-LC method was validated with respect to linearity, accuracy, precision and robustness. The percentage recovery for the (R,R)-enantiomer in bulk drug samples ranged from 98.1 to 104.4%. The test solution was found to be stable in the mobile phase for 48 h after preparation. 相似文献
124.
Sreeja Thulasi Jisha Babu Adarsh Babukuttannair Viji Sreemathi Ramavarma Luxmi Varma 《Tetrahedron》2010,66(27-28):5270-5276
A seemingly ipso-like nucleophilic substitution of the upper rim of p-tert-butylcalix[4]arene is accomplished by an indirect method involving calix[4]arene derived bis(spirodienone). This method not only provides both mono and 1,3-diaryloxy calixarenes but also enables the synthesis of upper rim monothio substituted calix[4]arenes. A modification of the methodology can be successfully extended for the selective synthesis of mono- and 1,3-diquinone calix[4]arenes having free hydroxyl groups at the lower rim, in fewer steps. 相似文献
125.
Miłosz Kadziński Marco Cinelli Krzysztof Ciomek Stuart R. Coles Mallikarjuna N. Nadagouda Rajender S. Varma Kerry Kirwan 《European Journal of Operational Research》2018,264(2):472-490
Nanomaterials (materials at the nanoscale, meters) are extensively used in several industry sectors due to the improved properties they empower commercial products with. There is a pressing need to produce these materials more sustainably. This paper proposes a Multiple Criteria Decision Aiding (MCDA) approach to assess the implementation of green chemistry principles as applied to the protocols for nanoparticles synthesis. In the presence of multiple green and environmentally oriented criteria, decision aiding is performed with a synergy of ordinal regression methods; preference information in the form of desired assignment for a subset of reference protocols is accepted. The classification models, indirectly derived from such information, are composed of an additive value function and a vector of thresholds separating the pre-defined and ordered classes. The method delivers a single representative model that is used to assess the relative importance of the criteria, identify the possible gains with improvement of the protocol’s evaluations and classify the non-reference protocols. Such precise recommendation is validated against the outcomes of robustness analysis exploiting the sets of all classification models compatible with all maximal subsets of consistent assignment examples. The introduced approach is used with real-world data concerning silver nanoparticles. It is proven to effectively resolve inconsistency in the assignment examples, tolerate ordinal and cardinal measurement scales, differentiate between inter- and intra-criteria attractiveness and deliver easily interpretable scores and class assignments. This work thoroughly discusses the learning insights that MCDA provided during the co-constructive development of the classification model. 相似文献
126.
Ram K. Varma 《Pramana》2010,74(4):491-511
We discuss here the prediction, based on a formalism by the author, on the observable effects of a curl-free magnetic vector
potential on the macroscale as against the microscale of the Aharonov-Bohm effect. A new quantum concept — the ‘transition
amplitude wave’ — postulated in the formalism has already been shown to exhibit matter wave manifestations in the form of
one-dimensional interference effects on the macroscale. It was predicted by the formalism that the same entity would lead
to the detection of a curl-free magnetic vector potential on the macroscale. We describe here the manner of generation of
this quantum entity in an inelastic scattering episode and work out an algorithm to observe this radically new phenomenon,
the detection of a curl-free magnetic vector potential on the macroscale. We determine the various characteristic features
of such an observation which can then be looked for experimentally so as to verify the predicted effect, establishing thereby
the physical reality of the new quantum entity, and to fully validate the formalism predicting it. It is also shown that this
‘transition amplitude wave’ can be regarded as a novel kind of ‘quasiparticle’ excited in the charged particle trajectory
as a consequence of the scattering episode. 相似文献
127.
P. NishaS. Savitha Pillai K.G. SureshManoj Raama Varma 《Journal of magnetism and magnetic materials》2012,324(1):37-43
The influence of partial substitution of La by Dy on the magnetocaloric response of (La1−xDyx)0.67Ca0.33Mn0.9V0.1O3, where x=0.03, 0.15 and 0.25 is studied. Rietveld refinement of X-ray diffraction pattern using GSAS method shows that the compounds adopt the orthorhombic structure with Pnma space group. The systematic change in lattice parameters and magnetic phase transition indicates the substitution effect of Dy. From the magnetization isotherms at different temperatures, magnetic entropy change close to their respective transition temperatures (TC) has been evaluated. The maximum value of entropy change near TC is found to be about 4.8 J/kg K at 187.5 K for LCMVDy0.03, 2.45 J/kg K at 107.5 K for LCMVDy0.15 and 2.15 J/kg K at 92.5 K for LCMVDy0.25 at 4 T. Dy addition produces a reduction in TC and in magnitude of the magnetic entropy change. Even though the entropy change decreases with increasing Dy substitution the refrigerant temperature range, ΔT, is found to be 10 K for LCMVDy0.03, 31 K for LCMVDy0.15 and 35 K for LCMVDy0.25 compounds [90%] at 4 T. The field dependence of the magnetic entropy change is also analyzed showing the power law dependence, ΔSM∞Hn where n=0.75(2) for LCMVDy0.03, n=0.80(4) for LCMVDy0.15 and n=0.92(8) for LCMVDy0.25 compounds at their respective transition temperatures. The relative cooling power and its field dependance are also analyzed. 相似文献
128.
Heusler-like alloy Fe2CrAl was prepared and studied. Structure determination was done by X-ray. The structure was found to conform to the B2 type. Magnetic hyperfine fields in this sample were studied by the Mössbauer effect. The Mössbauer spectra were recorded over a range of temperature from 40 to 296 K. The Mössbauer spectra showed the co-existence of a paramagnetic part with a magnetic hyperfine portion at all recorded temperatures. Even with the distribution in the magnetic hyperfine field, the average hyperfine field follows the (T/T c)3/2 law. The paramagnetic part of the hyperfine field is explained in terms of the clustering of Cr atoms. 相似文献
129.
A simple protocol was established to synthesize 2,3-dialkyl indoles and various tetrahydrocarbazoles via Fischer indole synthesis. This method uses ceric ammonium nitrate as a catalyst for the Fischer indole synthesis with substituted phenyl hydrazine hydrochlorides and 2-butanone, phenyl propanal, and cyclohexanone. This process is a practical synthetic method for the preparation of various 2,3-disubstituted alkyl indoles and tetrahydrocarbazoles. 相似文献
130.
A high yield synthesis of alkyl azides is described from readily accessible alkyl bromides and sodium azide using a recyclable phase transfer catalyst, 18-crown-6 ether impregnated clay. 相似文献