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41.
Thennati Rajamannar Namasivayam Palani Kalpattu Kuppuswamy Balasubramanian 《合成通讯》2013,43(22):3095-3108
A simple procedure for the C-alkylation of cyclic 1,3-diketones have been reported using Triton B as base in aqueous conditions. 相似文献
42.
A microwave-assisted persulfate oxidation method followed by ion chromatographic determination of nitrate was developed for total nitrogen determination in atmospheric wet and dry deposition samples. Various operating parameters such as oxidation reagent concentrations, microwave power, and extraction time were optimized to maximize the conversion of total nitrogen to nitrate for subsequent chemical analysis. Under optimized conditions, 0.012 M K2S2O8 and 0.024 M NaOH were found to be necessary for complete digestion of wet and dry deposition samples at 400 W for 7 min using microwave. The optimized extraction method was then validated by testing different forms of organic nitrogen loaded to pre-baked filter substrates and NIST SRM 1648 (urban particulate matter), and satisfactory results were obtained. In the case of wet deposition samples, standard addition experiments were performed. The suitability of the method for real-world application was assessed by analyzing a number of wet and dry deposition samples collected in Singapore during the period of March-April 2007. The organic nitrogen content was 15% (wet) and 30% (dry) of the total nitrogen. During the study period, the estimated wet fluxes for nitrate (NO3−), ammonium (NH4+), organic nitrogen (ON), and total nitrogen (TN) were 16.1 ± 6.5 kg ha−1 year−1, 11.5 ± 5.7 kg ha−1 year−1, 3.8 ± 1.5 kg ha−1 year−1and 31.5 ± 13.2 kg ha−1 year−1, respectively, while the dry fluxes were 2.5 ± 0.8 kg ha−1 year−1, 1.4 ± 0.9 kg ha−1 year−1, 2.3 ± 1.4 kg ha−1 year−1 and 7.5 ± 2.6 kg ha−1 year−1, respectively. 相似文献
43.
Kandavelu Palani Ponnuswamy Ambalavanan Mon Nanjappa Gounder Ponnuswamy Velli Raghukumar Vaylakkavoor T Ramakrishnan 《Analytical sciences》2004,20(2):405-406
4-(4'-Diethylaminophenyl)-6-(4-methoxyphenyl)-(2-pyrrolidin-1-yl)-pyridine-3-carbonitrile (DMPPC) was studied by X-ray diffraction methods due to its non-linear optical properties. The pyrrolidine and pyridine rings adopt half-chair and planar conformations, respectively. The molecules in the crystal are stabilized by C-H...O and C-H...N types of intermolecular interactions in addition to van der Waals forces. 相似文献
44.
Dr. Bo Jiang Dr. Tedi-Marie Usher Dr. Palani Raja Jothi Benard Kavey Prof. Dr. Gabriel Caruntu Prof. Dr. Katharine Page 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(32):8365-8371
Surface adsorbates and surrounding matrix species have been demonstrated to affect the properties of nanoscale ferroelectrics and nanoscale ferroelectric composites; potentially counteracting performance losses that can occur in small particle sizes. In this work, the effects of nonpolar oleic acid (OA) and polar tetrafluoroborate (BF4−) ligand capping on the surface of various sizes of BaTiO3 nanocubes have been investigated with combined neutron diffraction and neutron pair distribution function (PDF), density functional theory (DFT), and ab initio molecular dynamics (AIMD) methods. The low real space PDF region provides an unobstructed view of rhombohedral (split short and long) Ti−O distances in BaTiO3 nanocubes, mimicking the well-established order-disorder local structure found in bulk BaTiO3. Interestingly, the intermediate-range order in nanocubes is found to be orthorhombic, rather than tetragonal. It is concluded that polar ligands adsorbed at BaTiO3 surfaces stabilize the correlation length scale of local rhombohedral distortions in ferroelectric nanoparticles relative to nonpolar ligands. 相似文献
45.
Shuwen He Peng Li Xing Dai Hong Liu Zhong Lai Dong Xiao Casey C. McComas Chunyan Du Yuehui Liu Jingjun Yin Qun Dang Nicolas Zorn Xuanjia Peng Ravi P. Nargund Anandan Palani 《Tetrahedron letters》2017,58(14):1373-1375
We report a general approach for the synthesis of 5,6-dihydroindolo-naphthyridine ring system via an intramolecular cyclization of the indole NH to an alkene moiety as the key step. 相似文献
46.
E. Thandapani A. R. Ragavan G. Palani 《Journal of Applied Mechanics and Technical Physics》2012,53(3):408-421
An analysis is performed to study the heat transfer characteristics of natural convection over a vertical cone under the combined
effects of a magnetic field and thermal radiation. The cone surface is subjected to a variable surface temperature. The fluid
considered is a gray absorbing/emitting, but non-scattering medium. The boundary layer equations governing the flow are reduced
to non-dimensional equations using non-dimensional quantities valid in the free-convection regime. The resulting non-dimensional
governing equations are solved by an implicit finite-difference method of the Crank-Nicolson type, which is rapidly convergent
and unconditionally stable. Numerical results are obtained for velocity, temperature, local and average skin friction, and
local and average Nusselt numbers for various values of parameters occurring in the problem and are presented in the graphical
form. Excellent agreement of the results obtained with available data is demonstrated. 相似文献
47.
The present numerical analysis addresses free convection flow of a viscous incompressible fluid along an inclined semi-infinite flat plate considering the variation of viscosity and thermal diffusivity with temperature. The governing equations are developed with the corresponding boundary conditions are transformed to non-dimensional form using the appropriate dimensionless quantities. Due to complexity in the transformed governing equations, analytical solution will fail to produce a solution. Hence, most efficient and unconditionally stable implicit finite difference method of Crank-Nicolson scheme has been used to solve the governing equations. Numerical results are obtained for different values of the viscosity, thermal conductivity, inclination angle, Grashof number, and Prandtl number. The overall investigation of the variation of velocity, temperature, shearing stress and Nusselt number are presented graphically. To examine the accuracy of the present approximate results, the present results are compared with the available results. 相似文献
48.
A remarkable solvent preference for dehydrobromination to yield 10-Undecynoic acid (5) and 9-Undecynoic acid (6) is observed in the case of 10,11-dibromoundecanoic acid (1). Thus, 10-Undecenoic acid can be easily and quantitatively converted to 6 in PEG-400, while 5 is produced in PEG-200. 5 can also be obtained in non-polar solvents with PEG-200/400 as a phase transfer catalyst. 相似文献
49.
Vignesh R. A. Shalini Kumari Puja Poddar Dibakar Dhara Souvik Maiti 《Macromolecular bioscience》2020,20(8)
Multicellular tumor spheroid (MCTS) mimics microenvironment for tumor formation and provides predictive insight for in vivo tests. The hanging drop (HD) method of spheroid generation is cost effective, but it is limited by a long time duration for spheroid development and a low rate of formation of larger spheroids. Toward addressing those limitations, thermoresponsive copolymers with poly(N‐isopropylacrylamide) (p(NIPA)) backbone are developed, to be used as additives in the MCTS formation via HD method. Upon investigation it is found that in the presence of the polymer, robust and compact spheroids are formed in a short duration of 48 h. Larger spheroids (350–600 µm) can be formed by increasing the number of cells. Spheroids are characterized for their 3D shape and different cellular layers, and drug uptake study is done to prove the efficacy of the spheroids generated in drug screening. 相似文献
50.
Ajithkumar Arumugam Pushbaraj Palani Mageshwari Anandan Dr. Venkatramaiah Nutalapati Dr. Gopal Chandru Senadi 《European journal of organic chemistry》2023,26(12):e202300100
Highly functionalized quinazolin-4(3H)-ones were synthesized from reactions of N-aryl-2-aminobenzamides with trialkylamines under photocatalytic conditions by using eosin Y (EY) as a catalyst. The reaction proceeds under mild conditions in aqueous acetonitrile and has a broad substrate scope. Mechanistic studies disclosed the electron-donor nature of the intermediate 2,3-dihydroquinazolin-4(1H)-one ( 3’ ) in the photocatalytic cycle to afford the 2,3-disubstituted-quinazolin-4(3H)-ones ( 3 ). This methodology has been extended to synthesize benzo [4,5] imidazole[1,2-c] quinazolines and 3 aa on a large scale. Furthermore, the synthesis of potent central nervous system depressant (CNS) drug molecules such as methaqualone ( 3 la ) and mecloqualone ( 3 pa ) was also achieved successfully. 相似文献