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41.
Aswathanarayana Srinivasa Kittappa M. Mahadevan Vijaykumar Hulikal 《Monatshefte für Chemie / Chemical Monthly》2008,10(1):255-259
Antimony(III) sulfate is found to catalyze the imino Diels-Alder reaction of Schiff’s bases with N-vinylpyrrolidin-2-one to afford 2-aryl-4-(2′-oxopyrrolidinyl-1′)-1,2,3,4-tetrahydroquinolines. One-pot synthesis of 1,2,3,4-tetrahydroquinolines
from 3-nitro benzaldehyde and aromatic amines with N-vinylpyrrolidin-2-one catalyzed by antimony(III) sulfate is also reported. This catalyst is inexpensive, easily available,
and it was also found that catalyst could be recovered quantitatively and reused without much loss of catalytic activity. 相似文献
42.
Sreeram Kalarical Janardhanan Indumathy Ramasamy Balachandran Unni Nair 《Transition Metal Chemistry》2008,33(1):127-131
Natural polymers like chitosan and starch have been employed as templates for the preparation of iron oxide nanoparticles.
The templates offer selective binding sites for Fe(II) under aqueous conditions. Controlled drying and subsequent removal
of the template backbone enables the synthesis of spatially separated iron oxide nanoparticles. The crystalline character
of the iron oxide and near narrow particle size distribution pattern have been confirmed through powder XRD, Photon Correlation
Spectroscopy, and TEM measurements. The crystallite sizes of the particles were found to be 26–35 nm irrespective of the nature
of the template. 相似文献
43.
Subramanian?Mohanakrishnan?Anusha Santharam?Leelaram Mahadevan?SurianarayananEmail author 《Applied biochemistry and biotechnology》2016,179(6):1041-1059
Bioplastic production from microbial sources is an emerging area which provides opportunities even to convert the wastes into bioplastics. Poly (3-hydroxybutyric acid), commonly called as PHB, is a bioplastic, which is stored as intracellular cytoplasmic inclusions in microorganisms. The objectives of this study are to calorimetrically monitor the PHB production and evaluate the thermokinetic data in a bioreaction calorimeter (BioRC1e). Thus, a well-known PHB-producing bacteria Ralstonia eutropha was selected for batch process in a bioreaction calorimeter. The metabolic heat generated was found to be correlated with the biomass, substrate consumption, oxygen uptake rate (OUR), carbon dioxide evolution rate (CER) and PHB production. The OUR pattern explained the oxidative metabolism of the strain R. eutropha. The heat yields due to biomass and glucose consumption during PHB production were found to be 12.56 and 13.56 kJ/g, respectively. The oxycalorific value obtained for the PHB production was 443.80 kJ/mol of O2. The concentration of PHB obtained in BioRC1e was 4.33 g/L with a production rate of 0.09 g/L/h. The chemical structure of the extracted PHB by R. eutropha was confirmed using fourier transform infrared spectroscopy (FT-IR) and 1H and 13C nuclear magnetic resonance (NMR) analysis. 相似文献
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The pioneering works of Murat and Tartar (Topics in the mathematical modeling of composite materials. PNLDE 31. Birkhäuser, Basel, 1997) go a long way in showing, in general, that problems of optimal design may not admit solutions if microstructural designs are excluded from consideration. Therefore, assuming, tactilely, that the problem of minimizing the first eigenvalue of a two-phase conducting material with the conducting phases to be distributed in a fixed proportion in a given domain has no true solution in general domains, Cox and Lipton only study conditions for an optimal microstructural design (Cox and Lipton in Arch. Ration. Mech. Anal. 136:101–117, 1996). Although, the problem in one dimension has a solution (cf. Kre?n in AMS Transl. Ser. 2(1):163–187, 1955) and, in higher dimensions, the problem set in a ball can be deduced to have a radially symmetric solution (cf. Alvino et al. in Nonlinear Anal. TMA 13(2):185–220, 1989), these existence results have been regarded so far as being exceptional owing to complete symmetry. It is still not clear why the same problem in domains with partial symmetry should fail to have a solution which does not develop microstructure and respecting the symmetry of the domain. We hope to revive interest in this question by giving a new proof of the result in a ball using a simpler symmetrization result from Alvino and Trombetti (J. Math. Anal. Appl. 94:328–337, 1983). 相似文献
46.
We consider a microscopic model for the failure of soft adhesives in tension based on ideas of bond rupture under dynamic loading. By focusing on adhesive failure under loading at constant velocity, we demonstrate that bimodal curves of stress against strain may occur due to effects of finite polymer chain or bond length and characterize the loading conditions under which such bimodal behavior is observed. The results of this analysis are in qualitative agreement with experiments performed on unconfined adhesives in which failure does not occur by cavitation. 相似文献
47.
We have examined the formation of a local moment by considering various defects in ZnO. The localization of the defect induced state is found to determine the presence/absence of a local moment. A lot of attention on the probable origin of magnetism in wide band gap oxides has focused on cation vacancies. Here we show that oxygen interstitial atoms give rise to a large magnetic moment which results in a spin polarization of both the conduction and valence bands, in addition to spin polarized gap states. A Stoner mechanism is invoked and the relevant Stoner parameters are determined to be 0.7 eV for an oxygen atom in the presence of an oxygen interstitial but reduced to 0.2 eV on oxygen in the presence of a Zn vacancy. 相似文献
48.
Leslie W. Deady Andrew B. Hughes Indumathy B. Mahadevan Nurul H. Quazi Leann M. Tilley 《合成通讯》2013,43(5):803-820
The synthesis of fluorescent 2,10-derivatives of the title chromophore are described. The substituents contain amino-reactive N-hydroxysuccinimde ester and thiol-reactive iodoacetamide groups for attachment to biomolecules. A phosphate derivative was also prepared as an enzyme substrate. 相似文献
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