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41.
Glycosyl bromides were prepared in very good yields by bromination of the corresponding anomeric hydroxyl group using a 1:1 mixture of triphenyl phosphite and bromine as reagent. 相似文献
42.
Rohini Mani Michael Fischer Joby E. Joy J. Gopalakrishnan Martin Jansen 《Solid State Sciences》2009,11(1):189-194
We describe an exploratory investigation of the structure and electronic properties of new ruthenium(IV) pyrochlore oxides and their manganese-substituted derivatives. Our investigations have revealed several, hitherto unreported, electronic ground states for these materials: a metallic and Pauli paramagnetic state for BiPbRu2O6.5 that turns into a semiconducting ferromagnetic spin-glass state at 50 K for BiPbRuMnO6.5; a metallic state that likely shows a charge density wave (CDW) instability at 50–225 K for Bi1.50Zn0.50Ru2O6.75 that is suppressed by manganese substitution in Bi1.50Zn0.50Ru1.75Mn0.25O6.50; and a metallic ferromagnetic spin-glass like state for Pb2Ru1.75Mn0.25O6.15. The results indeed affirm the richness of the electronic properties of ruthenium-based metal oxides. 相似文献
43.
44.
M. Pimpalkhute M. A. Majali R. S. Mani 《Journal of Radioanalytical and Nuclear Chemistry》1986,103(2):105-116
A method for determining Human FSH in blood/serum by RIA is described. The radioiodination of FSH with125I is carried out under carefully controlled conditions such as, amount of initial activity of125I take for iodination, the reaction volume, and the reaction time, etc. The tracer FSH obtained thus is with minimum damage and optimum specific activity which is ideally suited for RIA. The shelf-life of the tracer is enhanced by the addition of benzyl alchol. The tracer can be conveniently stored at+4–6°C upto 10 weeks, avoiding the repeated freezing and thawing process. Antiserum to FSH is raised in rabbits by repeated injections via intramuscular route. The method utilizes polyethylene glycol /PEG/ as the separation system. Using this method, a number of control samples of men and women of reproductive age group are screened. This sensitive assay has a good validity and has an inter-assay variation less than 15%. 相似文献
45.
We study projective curvature tensor in K-contact and Sasakian manifolds. We prove that (1) if a K-contact manifold is quasi projectively flat then it is Einstein and (2) a K-contact manifold is ξ-projectively flat if and only if it is Einstein Sasakian. Necessary and sufficient conditions for a K-contact manifold to be quasi projectively flat and φ-projectively flat are obtained. We also prove that for a (2n + 1)-dimensional Sasakian manifold the conditions of being quasi projectively flat, φ-projectively flat and locally isometric to the unit sphere S
2n+1 (1) are equivalent. Finally, we prove that a compact φ-projectively flat K-contact manifold with regular contact vector field is a principal S
1-bundle over an almost Kaehler space of constant holomorphic sectional curvature 4. 相似文献
46.
Abdullah S. AlRamadan Moez Ben Houidi Julien Sotton Marc Bellenoue Bengt Johansson S. Mani Sarathy 《Proceedings of the Combustion Institute》2021,38(4):5539-5548
One approach to enhancing the thermal efficiency of combustion systems is to burn fuels at ultra-lean conditions (equivalence ratio below 0.5). It has been recently reported that the auto-ignition of some hydrocarbon fuels, under specific temperature, pressure, and mixture conditions, releases heat in three distinctive stages. The three auto-ignition stages can be divided as a first low-temperature auto-ignition stage with conventional low temperature, and a high-temperature stage separated into two sub-stages. This study presents ignition delay time measurements of n-heptane and methyl-cyclohexane (MCH) mixtures in a flat piston rapid compression machine (RCM) under ultra-lean conditions. It provides experimental evidence of three-stage auto-ignition. This phenomenon of delayed high-temperature heat release is seldom reported in the literature and this is the first time to be reported for these types of fuels. The experiments cover two binary n-heptane/MCH mixtures of 15/85 and 70/30 by volume, pressures of 11 bar and 16 bar, temperature range of 700 to 900 K, and equivalence ratio of 0.4. The RCM optical access was utilized for high-speed chemiluminescence imaging. Detailed chemical kinetic simulations in a homogenous batch reactor with variable volume were conducted to further interrogate the three-stage auto-ignition phenomenon. Chemiluminescence shows that three-stage auto-ignition occurs in the adiabatically compressed end-gas, which indicates that this phenomenon is chemically-driven and is not induced by a thermal stratification in the RCM experiments. The model predicts the features of three-stage auto-ignition, which were experimentally observed at temperatures approximately below 750 K. As expected, significant discrepancies are observed in the ignition delays of experiment and simulation in the negative temperature coefficient (NTC) region. The simulation of the n-heptane/MCH 70/30 mixture shows better agreement with experiments in the Positive Temperature Coefficient (PTC) region compared to the 15/85 mixture. 相似文献
47.
Ashutosh Tiwari Rajendra Kumar Mani Prabaharan Ravi R. Pandey Premlata Kumari Anurag Chaturvedi A. K. Mishra 《先进技术聚合物》2010,21(9):615-620
A nanofibrous polyaniline (PANI) thin film was fabricated using plasma‐induced polymerization method and explored its application in the fabrication of NO2 gas sensor. The effects of substrate position, pressure, and the number of plasma pulses on the PANI film growth rate were monitored and an optimum condition for the PANI thin film preparation was established. The resulting PANI film was characterized with UV–visible spectrophotometer, FTIR, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The PANI thin film possessed nanofibers with a diameter ranging from 15 to 20 nm. The NO2 gas sensing behavior was studied by measuring the change in electrical conductivity of PANI film with respect to NO2 gas concentration and exposure time. The optimized sensor exhibited a sensitivity factor of 206 with a response time of 23 sec. The NO2 gas sensor using nanofibrous PANI thin film as sensing probe showed a linear current response to the NO2 gas concentration in the range of 10–100 ppm. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
48.
Metin Ak Gülbanu Koyundereli Çılgı Ferah Diba Kuru Halil Cetişli 《Journal of Thermal Analysis and Calorimetry》2013,111(2):1627-1632
Thermal behavior of 2,4,6-tris(4-(1H-pyrrol-1-yl)phenoxy)-1,3,5-triazine monomer, polypyrrole, and their star shaped copolymer, were investigated using TG and DTA methods. It was found that Tria melts at 517 K and after than it starts to decompose. Decomposition proceeded in two stages which were corresponding to removal of branched groups and remaining core structure degradation, respectively. Polypyrrole and copolymer showed similar thermal behaviors. These compounds decomposed in three stages which are removal of solvent, removal of dopant anion and rest of structure decomposition. The calculation of activation energies of all reactions were realized using model-free (KAS and FWO) methods. The graphs were prepared which show the alteration of activation energy with decomposition ratio. Thermal analysis results showed that dopant anion and solvent removal activation energy values for copolymer are lower than polypyrrole. Star shaped loose-packed novel structure greatly facilitates solvent and dopant anion removal from copolymer. It can be concluded also that thermal analysis can be used as predict package structure of conducting polymers. 相似文献
49.
50.
Intramolecular Aza‐Diels‐Alder Cyclization of a Dimerized Citral with Anilines Catalyzed by InCl3 下载免费PDF全文
A series of aza‐polycyles containing octahydroacridine core were prepared via an intramolecular aza‐Diels‐Alder reaction of a dimerized citral with various aromatic amines. This reaction is efficiently catalyzed by InCl3 at ambient temperature to afford the corresponding cyclized products in moderate to good yields. 相似文献