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31.
Powder XRD investigations on dotriacontane-decane and dotriacontane-decanol mixtures are made. Phase strength, phase separation
and formation of superlattices are discussed. The role of tunnel-like defects is considered. 相似文献
32.
33.
Kandavelu Palani Ponnuswamy Ambalavanan Mon Nanjappa Gounder Ponnuswamy Hemmige S Yathirajan Basappa Prabhuswamy Chapuradoddy R Raju Padmarajaiah Nagaraja Sheena Shashikanth 《Analytical sciences》2004,20(2):403-404
2-Chloro-3-(beta-nitrovinyl)quinoline (CNQ) was crystallographically studied owing to its medicinal properties and its occurrance in numerous commercial products, including pharmaceuticals, fragrances and dyes. The vinyl group is planar, and takes up an extended conformation. An hydrogen bonding of C-H...N type helps to stabilize the molecules in the unit cell. 相似文献
34.
Matthew W. Brenner Veera M. Boddu Ashok Kumar 《Applied Physics A: Materials Science & Processing》2014,117(4):1849-1857
This study focuses on the effect of carbon precursor on the carbon nanotube (CNT) morphology and energy dissipation. Benzene, toluene, and m-xylene were used as carbon precursors for the synthesis of CNT forests following a chemical vapor deposition process. The results indicate that substituents on the benzene ring increase entanglement in the CNT forests. The absorbed energy was slightly greater for CNT forests synthesized using m-xylene than for toluene, but was much smaller for benzene. When compressed to a strain of 0.67, the toluene CNTs absorbed more energy than the m-xylene CNTs. The restitution was much higher for the forests synthesized with m-xylene than toluene while it further decreased for the forests made with benzene. A strong correlation is also observed between the average diameter of the CNTs and the number of methyl substituents on the benzene ring. The control of the entanglement of the CNT forests can potentially be used to design high energy absorbing composites for blast energy dissipation. 相似文献
35.
Banavara N. Shashikanth Artan Sheshmani Scott David Kelly Jerrold E. Marsden 《Theoretical and Computational Fluid Dynamics》2008,22(1):37-64
We present a (noncanonical) Hamiltonian model for the interaction of a neutrally buoyant, arbitrarily shaped smooth rigid
body with N thin closed vortex filaments of arbitrary shape in an infinite ideal fluid in Euclidean three-space. The rings are modeled
without cores and, as geometrical objects, viewed as N smooth closed curves in space. The velocity field associated with each ring in the absence of the body is given by the Biot–Savart
law with the infinite self-induced velocity assumed to be regularized in some appropriate way. In the presence of the moving
rigid body, the velocity field of each ring is modified by the addition of potential fields associated with the image vorticity
and with the irrotational flow induced by the motion of the body. The equations of motion for this dynamically coupled body-rings
model are obtained using conservation of linear and angular momenta. These equations are shown to possess a Hamiltonian structure
when written on an appropriately defined Poisson product manifold equipped with a Poisson bracket which is the sum of the
Lie–Poisson bracket from rigid body mechanics and the canonical bracket on the phase space of the vortex filaments. The Hamiltonian
function is the total kinetic energy of the system with the self-induced kinetic energy regularized. The Hamiltonian structure
is independent of the shape of the body, (and hence) the explicit form of the image field, and the method of regularization,
provided the self-induced velocity and kinetic energy are regularized in way that satisfies certain reasonable consistency
conditions.
相似文献
36.
P. B. Shashikanth P. B. V. Prasad G. Sambasiva Rao 《Crystal Research and Technology》1999,34(10):1287-1292
Studies on thin dotriacontane hydrocarbon in the form of thin films were made by employing Oblique Incidence Reflection Microscopy (OIRM). Information related to substructure and striations were discussed. 相似文献
37.
Banavara N. Shashikanth 《Journal of Nonlinear Science》2010,20(1):81-103
A method is presented for constructing point vortex models in the plane that dissipate the Hamiltonian function at any prescribed
rate and yet conserve the level sets of the invariants of the Hamiltonian model arising from the SE (2) symmetries. The method
is purely geometric in that it uses the level sets of the Hamiltonian and the invariants to construct the dissipative field
and is based on elementary classical geometry in ℝ3. Extension to higher-dimensional spaces, such as the point vortex phase space, is done using exterior algebra. The method
is in fact general enough to apply to any smooth finite-dimensional system with conserved quantities, and, for certain special
cases, the dissipative vector field constructed can be associated with an appropriately defined double Nambu–Poisson bracket.
The most interesting feature of this method is that it allows for an infinite sequence of such dissipative vector fields to
be constructed by repeated application of a symmetric linear operator (matrix) at each point of the intersection of the level
sets. 相似文献
38.
Atanu Biswas Sanghoon Kim Roselayne Ferro Furtado Carlucio Roberto Alves Megan Buttrum Veera Boddu 《International Journal of Polymer Analysis and Characterization》2018,23(6):577-589
Acylation of polysaccharides is a commercially important reaction and is usually performed in a process involving the polysaccharide, an acid anhydride, and an inorganic acid. As an alternative to inorganic acid, many catalysts, including some metal chlorides, have been previously reported as catalysts. In this work, we took a more comprehensive look at several metal chlorides to observe trends and reactivities among them, particularly relating to reaction temperature, time, and amount of acetic anhydride used. Iodine was also included for comparison. Almost all the metal chlorides studied were found to be active as catalysts for the acetylation of starch under suitable reaction conditions. However, each metal chloride had a somewhat different reactivity with a different optimal temperature needed for satisfactory reactions to take place. The molecular weight of the starch acetate products decreased in all cases observed. The reactivity trends among the metal halides seemed to correlate both with the ease of complexation between the halide and the substrate and with the acidity of the metal chloride. Characterization was achieved through 13?C NMR, FT-IR, thermogravimetric analysis and size exclusion chromatography. 相似文献
39.
Pradeep K. Vuppala Sai P. Boddu Edward B. Furr Christopher R. McCurdy Bonnie A. Avery 《Chromatographia》2011,74(9-10):703-710
A simple, sensitive and rapid ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) method was developed and validated for the quantification of mitragynine in rat plasma using amitriptyline hydrochloride as an internal standard. Sample preparation involved a one-step liquid?Cliquid extraction using methyl t-butyl ether. Mitragynine was separated on an Acquity UPLC? BEH HILIC column using isocratic elution with a mobile phase of 10 mM ammonium formate buffer containing 0.1% formic acid:acetonitrile (15:85, v/v). At a flow rate of 0.2 mL min?1, the retention time of mitragynine was found to be 1.3 min. Ionization was performed in the positive ion electrospray mode. The selected mass-to-charge (m/z) ratio transition of mitragynine ion [M + H]+ used in the selected ion recording (SIR) was 399.1. The calibration curve was found to be linear over a concentration range of 1?C5,000 ng mL?1 (r = 0.999) with a lower limit of quantification (LLOQ) of 1 ng mL?1. Intra- and inter-day assay variations were found to be less than 15%. The extraction recoveries ranged from 85?C93% at the three concentrations (2, 400 and 4,000 ng mL?1) in rat plasma. This method was successfully used to quantify mitragynine in rat plasma following intravenous administration of the compound. 相似文献
40.
Biswanath Das Digambar Balaji Shinde Boddu Shashi Kanth Jayprakash Narayan Kumar 《Helvetica chimica acta》2011,94(8):1477-1480
N‐Benzoylhydrazones (=N′‐alkylidene‐substituted benzohydrazides) 1 are allylated efficiently by reaction with allyl bromide ( 2 ) in the presence of Zn in aqueous NH4Cl solution. The products 3 are formed in excellent yields (85–94%) within 35–50 min (Scheme, Table). 相似文献