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91.
Complementary α-alkylation approaches for a sterically hindered spiro[pyrazolopyranpiperidine]ketone
Chris Limberakis Jianke Li Gayatri Balan David A. Griffith Daniel W. Kung Colin Rose Derek Vrieze 《Tetrahedron letters》2012,53(20):2543-2547
Complementary α-alkylation methods are used to derivatize a sterically hindered spiro[pyrazolopyranpiperidine]ketone. More specifically, enolate alkylations in the presence of DMPU and aldol condensations are employed to deliver these compounds. 相似文献
92.
Yu-Ting Cheng Tzu-Ray Shan Bryce Devine Donghwa Lee Tao Liang Beverly B. Hinojosa Simon R. Phillpot Aravind Asthagiri Susan B. Sinnott 《Surface science》2012,606(15-16):1280-1288
Cu/ZnO heterogeneous systems are used to catalyze the CO2 hydrogenation to methanol, but questions remain about the nature of the active site and the role of Cu–ZnO interactions in the catalyst performance. The way in which ZnO surfaces support Cu clusters and stabilize their active sites is a key factor for maintaining catalyst activity. Processes such as sintering, alloying and encapsulation may play an important role in the activity of the catalyst but are difficult to model directly with density functional theory (DFT). In this work, we report the development of charge-optimized many-body (COMB) potentials to model the Cu/ZnO system. This potential is then used in conjugation with the dimer method, which uses the first derivative of the potential energy and the initial state of the transition to find saddle points, to examine the migration barriers of Cu adatoms on Cu and ZnO surfaces. These findings are validated against the results of density functional theory (DFT) calculations and published experimental data. 相似文献
93.
Raluca M. Balan 《Journal of Fourier Analysis and Applications》2012,18(6):1113-1145
Using tools from the theory of stationary random distributions developed in It? (Mem. Coll. Sci., Univ. Kyoto, Ser. A: Math., 28:209?C223,?1954) and Yaglom (Theory Probab. Appl., 2:273?C320,?1957), we introduce a new class of processes which can be used as a model for the noise perturbing an SPDE. This type of noise is not necessarily Gaussian, but it includes the spatially homogeneous Gaussian noise introduced in Dalang (Electron. J. Probab. 4(6)?1999), and the fractional noise considered in Balan and Tudor (Stoch. Process. Appl., 120:2468?C2494,?2010). We derive some general conditions for the existence of a random field solution of a linear SPDE with this type of noise, under some mild conditions imposed on the Green function of the differential operator which appears in this equation. This methodology is applied to the study of the heat and wave equations (possibly replacing the Laplacian by one of its fractional powers), extending in this manner the results of Balan and Tudor (Stoch. Process. Appl., 120:2468?C2494,?2010) to the case H<1/2. 相似文献
94.
P. R. Aravind P. Shajesh P. Mukundan K. G. K. Warrier 《Journal of Sol-Gel Science and Technology》2009,52(3):328-334
Ambient pressure drying has been carried out for the synthesis of silica–titania aerogel monoliths. The prepared aerogels
show densities in the range 0.34–0.38 g/cm3. The surface area and pore volume of these mixed oxide aerogels are comparable to those of the supercritically dried ones.
The surface area for 5wt% titania aerogel has been found to be as high as 685 m2/g with a pore volume of 2.34 cm3/g and the 10wt% titania aerogel has a surface area of 620 m2/g with a pore volume of 2.36 cm3/g. Some gels were also made hydrophobic by a surface treatment with methyltrimethoxysilane and trimethylchlorosilane. The
surface modified aerogels possess high surface areas in the range of 540–640 m2/g, and are thermally stable in terms of retaining hydrophobicity up to a temperature of 520 °C. The pore size distribution
of the aerogels clearly indicates the preservation of the aerogel structure. High Resolution Transmission Electron microscopy
has been employed to characterise the aerogels and Fourier Transform infrared spectroscopy to study the effect of titania
addition to silica and the surface modification. X-ray diffraction patterns were recorded to verify the molecular homogeneity
of the aerogel. 相似文献
95.
Jo?l?Coulon Ilan?Thouvenin Fadi?Aldeek Lavinia?Balan Rapha?l?Schneider 《Journal of fluorescence》2010,20(2):591-597
Highly fluorescent CdTe quantum dots (QDs) stabilized by thioglycolic acid (TGA) were prepared by an aqueous solution approach
and used as fluorescent labels in detecting yeast cells. Sugars (mannose, galactose or glucose) were adsorbed on CdTe@TGA
QDs and the interaction of these nanoparticles with yeast cells was studied by fluorescence microscopy. Results obtained demonstrate
that galactose and mannose functionalized QDs associate respectively with Kluyveromyces bulgaricus and Saccharomyces cerevisiae yeast strains due to saccharide/lectin specific recognition. Glucose-functionalized CdTe QDs, which are not recognized by
cell lectins, preferentially localize in the bud scars of S. cerevisiae. 相似文献
96.
Gulea A. P. Mitkevich N. L. Chumakov Yu. M. Petrenko P. A. Balan G. G. Burduniuc O. S. Tsapkov V. I. 《Russian Journal of General Chemistry》2019,89(7):1415-1423
Russian Journal of General Chemistry - 4-(2-Methoxyphenyl)-, 4-(3-methoxyphenyl)-, and 4-(4-memoxyphenyl)-2-[(5-mttofuryl)methylene]-hydrazine carboxamide (HL1–3) react with hydrates of... 相似文献
97.
Gulea A. P. Graur V. O. Chumakov Yu. M. Petrenko P. A. Balan G. G. Burduniuc O. S. Tsapkov V. I. Rudic V. F. 《Russian Journal of General Chemistry》2019,89(5):953-964
Russian Journal of General Chemistry - The reaction of N-(prop-2-en-1-yl)hydrazinecarbothioamide with substituted 2-hydroxybenzaldehydes afforded the corresponding Schiff bases which were used as... 相似文献
98.
Aravind Surendran Lathika Paramashivan Sivapirakasam Suthangathan Mahadevan Surianarayanan 《Journal of Thermal Analysis and Calorimetry》2019,136(5):2183-2193
Journal of Thermal Analysis and Calorimetry - This paper addresses the thermal behavior of commonly used NaN3/KNO3 gas generant mixtures under different heating rates using simultaneous thermal... 相似文献
99.
Praveen K. Bayannavar Saba Kauser J. Shaikh S. Madan Kumar Mahadev N. Kumbar Aravind R. Nesaragi 《合成通讯》2019,49(16):2005-2016
A simple and convenient approach for the synthesis of pyrazolyl-tetrahydroindazolones via L-proline catalyzed three component domino reaction of arylhydrazine, dimedone and pyrazole aldehyde in polyethyleneglycol-400 (PEG-400) under microwave irradiation is described. This novel and green protocol proceeds smoothly in good to excellent yields and provides several advantages such as shorter reaction time, metal-free reaction conditions, simple work-up procedures. Also, recycling of the catalyst and solvent was observed without the loss of activity for three (03) runs. 相似文献
100.
Badis Haddag Farid Abed-Meraim Tudor Balan 《International Journal of Plasticity》2009,25(10):1970-1996
Sheet metal forming processes generally involve large deformations together with complex loading sequences. In order to improve numerical simulation predictions of sheet part forming, physically-based constitutive models are often required. The main objective of this paper is to analyze the strain localization phenomenon during the plastic deformation of sheet metals in the context of such advanced constitutive models. Most often, an accurate prediction of localization requires damage to be considered in the finite element simulation. For this purpose, an advanced, anisotropic elastic–plastic model, formulated within the large strain framework and taking strain-path changes into account, has been coupled with an isotropic damage model. This coupling is carried out within the framework of continuum damage mechanics. In order to detect the strain localization during sheet metal forming, Rice’s localization criterion has been considered, thus predicting the limit strains at the occurrence of shear bands as well as their orientation. The coupled elastic–plastic-damage model has been implemented in Abaqus/implicit. The application of the model to the prediction of Forming Limit Diagrams (FLDs) provided results that are consistent with the literature and emphasized the impact of the hardening model on the strain-path dependency of the FLD. The fully three-dimensional formulation adopted in the numerical development allowed for some new results – e.g. the out-of-plane orientation of the normal to the localization band, as well as more realistic values for its in-plane orientation. 相似文献