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1.
The synthesis and characterization of a new homologous series of compounds, the 2-cyano-1,3-phenylene bis[4-(4-n-alkoxyphenyliminomethyl)benzoates] derived from 2-cyanoresorcinol is reported. All the compounds are enantiotropic mesogens and exhibit the fascinating B7 mesophase. The characterization of the mesophase was performed using polarizing optical microscopy, differential scanning calorimetry, X-ray diffraction and electro-optical studies. 相似文献
2.
B. Sadashive Gowda G.S.V.L. Narasimham M.V. Krishna Murthy 《International Journal of Heat and Fluid Flow》1997,18(6):613-624
In this paper, a mathematical model for forced-air precooling of spherical food products in bulk is developed. The foods are arranged in horizontal layers stacked one above the other to form a rectangular parallelepiped with a vertical gap in between the product layers. The foods are cooled by chilled air blown along the height of the package. The governing equations for the conduction heat transfer in the foods, simultaneous heat and mass transfer at the food-air interface and in the air stream are solved numerically using finite-difference methods. A comprehensive numerical study is performed by varying the process parameters over a wide range. Typical results showing the variation of moist air properties along the height of the package and the effect of each parameter on the process time are presented. The ranges of parameters for advantageous operation of the precooling system are identified. Correlations are obtained for the process time based on the product center and mass-averaged temperatures in terms of process parameters. 相似文献
3.
K. Ravikumar B. Sridhar M. Mahesh V. V. Narayana Reddy 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(9):o574-o576
The crystal structures of pyranoquinolines 9‐fluoro‐5‐phenyl‐3,4,4a,5,6,10b‐hexahydro‐2H‐pyrano[3,2‐c]quinoline, C18H18FNO, and 9‐methyl‐5‐phenyl‐3,4,4a,5,6,10b‐hexahydro‐2H‐pyrano[3,2‐c]quinoline, C19H21NO, are isomorphous. In both structures, the pyran ring is exo to the six‐membered N‐heterocyclic ring formed in the cycloaddition step. The torsion angles across the phenyl linkage for the two structures are −91.2 (1) and −88.3 (2)°. The striking feature in both crystal packings is that they do not contain the expected conventional hydrogen bonds, in spite of the presence of good hydrogen‐bonding functionalities. Possible C—H⋯π interactions are, however, observed. 相似文献
4.
B. Sanjeeva Rao M. Ramakrishna Murthy 《Journal of Polymer Science.Polymer Physics》1989,27(6):1187-1194
Electron spin resonance (ESR) spectra of poly(acrylic acid) (PAA) γ-irradiated in air at room temperature and recorded at room temperature and at liquid-nitrogen temperature have been studied to identify the radiation products. The ESR spectra are composed of eight lines with hyperfine splittings of 23 ± 1 G and 11 ± 1 G. The method of least-squares total curve fitting, employing the Lorentzian line shape function, to the observed spectra enabled the assignment of the spectra. Computed spectra obtained by the superposition of a singlet and the spectra due to chain radicals are considered to give the best fits to the observed ESR spectra. The singlet is assigned to the radicals COOH, and the component 10-line spectra are assigned to the chain radicals CH3? CH? CH2 ~ and/or ~ CH2? CH? CH2 ~. The observed change in line shape with temperature of the ESR spectra is attributed to the hindered oscillations of the methyl groups about the Cα? Cβ bond axis of the chain radicals. The existence of the methyl groups is confirmed by the measurement of infrared absorption. 相似文献
5.
F. Sibel Salman Jayant R. Kalagnanam Sesh Murthy Andrew Davenport 《Journal of Heuristics》2002,8(2):215-239
For hard optimization problems, it is difficult to design heuristic algorithms which exhibit uniformly superior performance for all problem instances. As a result it becomes necessary to tailor the algorithms based on the problem instance. In this paper, we introduce the use of a cooperative problem solving team of heuristics that evolves algorithms for a given problem instance. The efficacy of this method is examined by solving six difficult instances of a bicriteria sparse multiple knapsack problem. Results indicate that such tailored algorithms uniformly improve solutions as compared to using predesigned heuristic algorithms. 相似文献
6.
T. K. V. Iyengar N. Srinivasacharyulu J. V. Ramana Murthy 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1988,39(5):649-667
An elliptic cylinder is performing oscillations parallel to either of the principal axes of the cross-sectional ellipse in a fluid particle suspension. The stream function governing the flow and the velocity components are determined in terms of Mathieu functions. The drag on the cylinder is evaluated and expressed in terms of two parametersK andK. The effects of the variation of the frequency parameter, eccentricity parameter and relaxation time parameter on the drag parametersK, K is studied numerically. 相似文献
7.
Kommareddi Nagesh S. Tata Murthy Karayigitoglu Cigdem John Vijay T. McPherson Gary L. Herman Michael F. O'Connor Charles J. Lee Young-Sook Akkara Joseph A. Kaplan David L. 《Applied biochemistry and biotechnology》1995,51(1):241-252
Applied Biochemistry and Biotechnology - Horseradish peroxidase has been used as a biocatalyst to synthesize a polymeric material from alkyl-substituted phenols. The synthesis is carried out in a... 相似文献
8.
H. K. Reimschuesel J. Marti N. S. Murthy 《Journal of polymer science. Part A, Polymer chemistry》1988,26(1):43-59
Copolymers of ethylene and chlorotrifluoroethylene that contain small amounts of units derived from perfluorohexylethylene show improved resistance of thermal stress cracking. This is a consequence of effects of these units on structural parameters of both the crystalline and amorphous phases. Those of the crystalline phase entail growth and organization of lamellae, whereas those of the amorphous phase are related to conformation and packing of polymer chains. The crystalline phase consists exclusively of alternately arranged units of ethylene and chlorotrifluoroethylene. The amorphous phase is characterized by chain segments composed of randomly distributed units derived from ethylene, chlorotrifluoroethylene, pairs of these two units, and units derived from perfluorohexylethylene. 相似文献
9.
10.
Five different polyaniline salts have been prepared by chemical polymerization of aniline in aqueous solution of different acids. The polyaniline base was obtained from the corresponding polyaniline salt by dedoping using aqueous ammonium hydroxide solution. Electron paramagnetic, electronic absorption, infrared spectral and conductivity measurements have been performed on the polyaniline salts and polyaniline bases. This composition and the extent of dopant in polyaniline salt systems have been determined. There is no definite correlation between the conductivity and the stoichiometric ratio between the polyaniline base and the acid, and also the spin concentration. 相似文献