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91.
Bal K Agrawal S Agrawal P S Yadav S Kumar J S Negi Namrata Varshney 《Bulletin of Materials Science》1991,14(4):967-971
In the series of the layered highT
c
superconductors (A)1,2 B2Ca
n−1Cu
n
O2n+3,4 (A=Tl or Bi;B=Ba or Sr), withn=number of consecutive Cu-O layers, the electron energy states of some of the Tl-based systems have been investigated. The
electron and phonon dispersion curves have been obtained. The electronic states near the Fermi level are dominated by the
hybridized Cu(d) and the O(p) orbitals. The dispersion curves are highly two-dimensional with very small dispersion alongc-axis. The number of bands is enhanced with increase in the number of the consecutive Cu-O planes (n). The present results agree with those obtained earlier for other superconducting phases. The phonons are overall dominated
by the vibrations of the light mass oxygen atom modes both lying in or outside the Cu-O planes. The low-frequency phonons
involve the motions of the heavier Tl, Ba atoms etc. 相似文献
92.
Shane M. Cardoso Christopher D. O'Connell Ryan Pivonka Corey Mooney Vijaya Chalivendra Arun Shukla Sze Yang 《Polymer Composites》2016,37(2):360-369
Multiwalled carbon nanotubes of 0.2% weight fraction are used as a sensory network for detecting and characterizing the damage of particulate epoxy composites under shear loading conditions. Three different weight fractions of carboxyl‐terminated butadiene acrylonitrile copolymer rubber [10 parts per hundred of epoxy resin (phr), 20 phr, and 30 phr] are used for toughening a thermoset epoxy composite. The electrical response of the specimens is measured, nearest the central shearing plane, using a four‐circumferential ring probe technique in conjunction with a high‐resolution data acquisition system. A collection of the electromechanical response results are reported with respect to the shear strain. The resistance changes observed under shear loading are related to nonlinear deformation mechanisms, void initiation, and growth around rubber particulate. With increasing rubber content, the strength of the material decreases and a greater drop in resistance is recorded as a result of decreased distance between neighboring carbon nanotubes (CNTs) due to declustering and straightening of molecular chains of host matrix. In the end, a comparison for 30 phr composites under shear loading with that of tensile and compression loading conditions is presented. For initial deformation, there is no change in resistance under shear loading condition; however, the significant resistance change can be noticed under both tension and compression. The specimen under shear loading conditions experiences smaller decrease in resistance when compared with both tension and compression. However, the decrease in resistance is higher for compression due to higher decrease in distance between neighboring CNTs. POLYM. COMPOS., 37:360–369, 2016. © 2014 Society of Plastics Engineers 相似文献
93.
Glycolytic depolymerization of polyethylene terephthalate (PET) bottle waste was attempted using ethylene glycol (EG) in the presence of chlorides of zinc, lithium, didymium, magnesium, and iron as catalysts. Virtual monomer bis (2‐hydroxyethyl terephthalate) (BHET) was obtained in all cases with nearly 74% yield, the highest yield being achieved with zinc chloride catalyst 0.5% w/w, PET : EG ratio 1 : 14 and 8 h under reflux conditions. The results were comparable to other catalysts like common alkalis, acids, and salts of some earth metals and zeolites used earlier although parameters of glycolysis were observed to vary depending on the catalyst. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
94.
Identification of yeast strains isolated from marcha in Sikkim, a microbial starter for amylolytic fermentation 总被引:1,自引:0,他引:1
Tsuyoshi N Fudou R Yamanaka S Kozaki M Tamang N Thapa S Tamang JP 《International journal of food microbiology》2005,99(2):135-146
Marcha or murcha is a traditional amylolytic starter used to produce sweet-sour alcoholic drinks, commonly called jaanr in the Himalayan regions of India, Nepal, Bhutan, and Tibet (China). The aim of this study was to examine the microflora of marcha collected from Sikkim in India, focusing on yeast flora and their roles. Twenty yeast strains were isolated from six samples of marcha and identified by genetic and phenotypic methods. They were first classified into four groups (Group I, II, III, and IV) based on physiological features using an API test. Phylogenetic, morphological, and physiological characterization identified the isolates as Saccharomyces bayanus (Group I); Candida glabrata (Group II); Pichia anomala (Group III); and Saccharomycopsis fibuligera, Saccharomycopsis capsularis, and Pichia burtonii (Group IV). Among them, the Group I, II, and III strains produced ethanol. The isolates of Group IV had high amylolytic activity. Because all marcha samples tested contained both starch degraders and ethanol producers, it was hypothesized that all four groups of yeast (Group I, II, III, and IV) contribute to starch-based alcohol fermentation. 相似文献
95.
The response of E-Glass/Vinyl ester curved composite panels subjected to underwater explosive loading has been studied. The work consists of experimental testing utilizing a water filled conical shock tube facility and computational simulations with the commercially available Ls-Dyna finite element code. The composite specimens are 0/90 biaxial laminates with a thickness of approximately 1.3 mm. The samples are round panels with curved midsections. The transient response of the plates is measured using a three-dimensional (3D) Digital Image Correlation (DIC) system, along with high speed photography. This ultra high speed system records full field shape and displacement profiles in real time. The DIC data and the computational results show a high level of correlation using the Russell error measure. 相似文献
96.
A new approach for natural dyeing with anthocyanin has been discussed along with a convenient method of extraction. Anthocyanin from Hibiscus flowers has been extracted by developing a method using methanolic solution of 4% citric acid. The new method gave better yield of anthocyanin as compared with methanolic solution of 0.1% hydrochloric acid. It has been also shown that pH of the extract plays an important role on the dye, thus by adjusting the pH of the extract at 4, dyeing of cotton and silk together with metal mordanting gave different colors. The best dyeing results were obtained for stannous mordanted fabrics in terms of fastness properties. The role of metal ion complexation of stannous salt with the dye extract has been confirmed through UV‐Vis and FTIR spectra. Antioxidant activity of the anthocyanin extract seemed to have contributed to enhance the fastness properties of the dyed fabrics. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
97.
P. S. Niranjan Ratna Shukla Santosh K. Upadhyay 《Journal of surfactants and detergents》2012,15(1):53-57
The aggregation behaviour of two cationic surfactants, viz. cetyl trimethyl ammonium bromide (CTAB) and N-cetyl pyridinium
chloride (CPC), in different concentrations of water-soluble polyacrylamide has been studied in alkaline medium by electrical
conductivity and surface tension measurements. A decrease in the critical micelle concentration (CMC) of the surfactant with
an increase in polymer content in the mixture was observed. The thermodynamic and surface parameters have been determined
and discussed. The results indicate that micellisation becomes more favourable at higher polymer content. 相似文献
98.
Prediction of thermodynamic properties and phase equilibria in fluid mixtures using a simple cubic equation of state is still a challenging problem. In this paper, we have predicted vapor/ liquid phase equilibria of several binary fluid mixtures using our previously developed improved Peng-Robinson equation of state and a theoretically consistent mixing rule. Our mixing rule combines the mixing rule of Wong-Sandier with a physically based combination rule. Mixtures are composed of nonpolar, nonassociating polar and associating polar fluids. Comparisons of theoretical predictions with experimental data show a very good performance of our approach in describing vapor/liquid phase equilibria of several mixtures, namely, carbon dioxide/ propane, ethane/hexane, butane/methanol, benzene/methanol, acetone/methanol, methanol/ ethanol, methanol/1-butanol, methanol/water and ethanol/water. 相似文献
99.
Manu Gupta P. K. Kamani R. K. Shukla 《Journal of Coatings Technology and Research》2013,10(2):189-198
This article deals with the treatment of barium sulfate extender pigment with iron oxide and its phenomenological adsorption mechanism in the presence of H+ and OH? ions in solution. The pH range taken in the present study is 5–6. By depositing a ferric oxide layer on barium sulfate particles a novel pigment with better optical and functional performance is obtained. This pigment in various coating systems improves physicochemical performance and acts as an active barrier. The treated pigments can be suitably used in different architectural and industrial coatings. The experimental techniques of surface treatment are discussed, along with the instrumental analysis by SEM, EDAX, XRD, etc. 相似文献
100.
In this work, we report electronic structure calculations aimed at computing the linear optical absorption spectrum and static
dipole polarizablity of a newly proposed boron-based planar aromatic compound borozene (B
12
H
6). For the purpose, we use the semiempirical INDO model Hamiltonian, accompanied by large-scale correlation calculations using
the multi-reference singles-doubles configuration-interaction (MRSDCI) approach. We present detailed predictions about the
energetics, polarization properties, and the nature of many-particle states contributing to various peaks in the linear absorption
spectrum. Our results can be used to characterize this material in future optical absorption experiments. We also argue that
one can deduce the aromaticity of the cluster from the optical absorption and static polarizability results. 相似文献