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71.
S. Lakshmi Reddy G. Udayabashkar Reddy R. Ramasubba Reddy G. Siva Reddy Ray L. Frost Tamio Endo 《Particuology》2013,11(3):340-345
The microwave synthesis of MnC2O4·2H2O nanoparticles was performed through the thermal double decomposition of oxalic acid dihydrate (C2H2O4·2H2O) and Mn(OAc)2·4H2O solutions using a CATA-2R microwave reactor. Structural characterization was performed using X-ray diffraction (XRD), particle size and shape were analyzed using transmission electron microscopy (TEM). The chemical in the structures was investigated using electron paramagnetic resonance (EPR) as well as optical absorption spectra and near-infrared (NIR) spectroscopies. The nanocrystals produced with this method were pure and had a distorted rhombic octahedral structure. 相似文献
72.
In this paper, we present an algorithm with an approximation factor of 2 for a Generalized, Multiple Depot, Multiple Travelling Salesman Problem (GMTSP) when the costs are symmetric and satisfy the triangle inequality. The algorithm requires finding a degree constrained minimum spanning tree which we compute using a Lagrangian relaxation. 相似文献
73.
N. Lingaiah N. Seshu Babu Rajesh Gopinath P. Siva Sankara Reddy P. S. Sai Prasad 《Catalysis Surveys from Asia》2006,10(1):29-39
The use of supported Pd catalysts, with low and high metal content, for the hydrodechlorination of chlorobenzene is presented in this article. Application of microwave irradiation during preparation of catalysts resulted in the synthesis of large Pd particles at moderate temperatures. The nature of the support played a key role in the formation of cationic Pd species. The extent of interaction of the Pd species with the support, the nature of metal precursor, particularly the residual chlorine on the surface were found to significantly affect the activity of the catalysts. In the case of bimetallic catalysts also microwave heating resulted in creation of bigger particles of Pd compared to those observed in conventionally heated catalysts. Besides, it minimized alloy formation as a result of which the activity of the catalysts in hydrodechlorination was found to be higher compared to that observed on conventionally prepared catalysts. Contrary to the general observation that low dispersed Pd catalysts are preferable for high stability, by means of the deposition-precipitation method adopted for catalyst preparation it was demonstrated that even highly dispersed (low Pd containing) catalysts can exhibit comparable activity and stability. An analysis of the nature of Pd species and its role in the stability of the catalysts is presented.IICT communication No. 051224 相似文献
74.
Chen Q Saltiel C Manickavasagam S Schadler LS Siegel RW Yang H 《Journal of colloid and interface science》2004,280(1):91-97
The aggregation behavior of colloidal single-walled carbon nanotubes (SWNT) in dilute aqueous suspensions was investigated using a novel light scattering measurement technique. The aggregation of SWNT in three suspensions was examined: (1) nanotubes after acid treatment; (2) as-received nanotubes stabilized by a nonionic surfactant; and (3) acid-treated nanotubes with nonionic surfactant. Continuous light scattering measurements of the SWNT suspensions (probing the 38-436 nm length scale) made over two weeks showed that the nanotubes in each sample formed networks with fractal-like structures. The as-received nanotubes were stable over the measurement period, while the acid-treated nanotube suspension showed greater dispersion variability over time, yielding looser structures at large length scales and more compact structures at smaller length scales. The addition of surfactant to the acid-treated suspension significantly enhanced nanotube dispersion. 相似文献
75.
Siva Kumar Talluri 《Tetrahedron》2007,63(39):9758-9763
An efficient enantioselective synthesis of (R)-selegiline has been achieved by two routes, via proline-catalyzed α-aminooxylation as well as α-amination of phenylpropanaldehyde as the key step. 相似文献
76.
J. Siva Kumar G. Narayana M. Chandra Shekar U. V. Subba Rao V. Hari Babu 《Crystal Research and Technology》1983,18(11):1437-1441
I–V characteristics of sandwiched Al–Sb2O3–Al structures have been studied for different thicknesses. The current-voltage curves in general exhibit three regions, ohmic, non ohmic and breakdown regions. The breakdown voltage increases whereas the dielectric strength decreases with increase in Sb2O3 film thickness. The electrical breakdown studies have been done for dc and ac voltages and optical photomicrographs of breakdown patterns during different stages of voltage have been taken and the results are explained. 相似文献
77.
Mingqing Xiao Yuan Lin James H. Myatt R. Chris Camphouse Siva S. Banda 《Journal of Applied Mathematics and Computing》2006,22(1-2):67-82
In this paper, we present a finite difference method for the implementation of the rotation of a circular cylinder in the incompressible flow field by solving the two-dimensional unsteady Navier-Stokes equations. The approach is to use staggered grid method so that the accuracy and order of convergence of the associated algorithms can be maintained. The proposed method is easy to be implemented and is effective. A set of simulations for the flow dynamics is provided to show the computational results. 相似文献
78.
R. K. Sankaranarayanan S. Siva A. Antony Muthu Prabhu N. Rajendiran 《Journal of inclusion phenomena and macrocyclic chemistry》2010,67(3-4):461-470
Effect of β-cyclodextrin (β-CD) on the absorption and fluorescence spectra of 3,4,5-trihydroxybenzoic acid (THB) have been studied buffer solutions of different pHs (pH ~1, pH ~7 and pH ~10). The study reveals that in all the above pHs THB forms 1:1 inclusion complex. The hydroxyl groups are present in the interior part of the β-CD cavity and carboxyl group is present in the hydrophilic part of the β-CD cavity. Dual luminescence is observed at pH ~1 and pH ~7 solutions which shows that intramolecular charge transfer present at these pH. The broad spectral maximum at pH ~10 indicates that intramolecular proton transfer is present in THB. 相似文献
79.
80.
Leela Prasad Kowtharapu Naresh Kumar Katari Christian A Sandoval Siva Krishna Muchakayala Vijay Kumar Rekulapally 《Journal of separation science》2022,45(10):1711-1726
Serotonin receptor antagonist drug Ondansetron hydrochloride injectable formulation containing all related substances was identified and quantified by a single, simple, sensitive, eco-friendly, and green high-performance liquid chromatography method. The disseverment of all impurities was achieved with the Discovery Cyano (250 × 4.6) mm, 5 μm column. The gradient program was composed of pH 5.7 phosphate buffer as mobile phase A and acetonitrile as mobile phase B. The flow rate, column compartment temperature, and detection wavelengths were 0.9 mL/min, 30°C, and 216 nm, respectively. The method was validated as per current regulatory guidelines. The obtained %relative standard deviation for the precision results was between 0.55 and 2.72% for all impurities. The correlation coefficient values from the linearity experiment for impurities and analyte were more than 0.995. The accuracy results were obtained between 88.4 and 113.0% for all impurities. Both sample and standard solutions showed 24 h stability at benchtop and refrigerator conditions. All impurities and analytes met the specificity and mass balance for all forced degradation conditions. Quality-by-design-based design of experiments was utilized to establish the method's robustness. Method greenness was assessed by using the current advanced tool green analytical procedure index, National Environmental Methods Index, and analytical eco-scale. 相似文献