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1.
Absolute total electron scattering cross sections for carbon dioxide have been measured at low electron energies using a photoelectron
source. The measurements have been carried out at 27 electron energies varying from 0.91–9.14 eV with an accuracy of ±3%.
The cross sections obtained in the present experiment have been compared with other measurements and theoretical computations. 相似文献
2.
3.
Spiro [3H-indole-3,2′-[4H] pyrido [3,2-e]-1,3-thiazine]-2,4′ (1H) diones, a class of previously unknown compound which does not form under conventional conditions, can be prepared by treatment of ‘in situ’ generated 3-indolylimine derivatives with 2-mercaptonicotinic acid under microwave irradiation in absence of any solvent or solid support in 85-92% yields in 3-8 min. The facile one pot reaction is generalized for a variety of ketones and amines to give pure pyrido [3,2-e] thiazine derivatives, which do not require further purification processes. 相似文献
4.
Kamlakar Avasthi Diwan S. Rawat Tilak Chandra Ashoke Sharon Prakas R. Maulik 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(6):o311-o313
In 5-benzyl-1,7-dimethyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-d]pyrimidine-4,6-dione, C14H14N4O2, which crystallizes in space group P, weak intermolecular C—H⋯O hydrogen bonds generate dimers. The isomeric compound 1-benzyl-5,7-dimethyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-d]pyrimidine-4,6-dione, C14H14N4O2, crystallizes in space group P21/n, and shows no such dimerization. Instead, it exhibits C—H⋯π interactions with the phenyl ring. In both structures, the molecules are linked by aromatic π–π-stacking interactions. 相似文献
5.
A new chelating resin was synthesised by the modification of styrene-divinylbenzene (2%) copolymer and incorporation of dithiocarbamate groups. The polydithiocarbamate resin was characterised by elemental analysis, thermal studies and IR studies. The analytical characteristics of the sorbent were established and optimum sorption conditions for Cu, Ni, Pb, Fe, As and Mn determined. The total sorption capacity of the resin was 37 mg g−1 for Ni(II), 35 mg g−1 for Cu(II), 29 mg g−1 for Fe(III) and 23 mg g−1 for Pb(II). The optimum pH for the removal of metal ions was 3-5 for Ni(II), 5 for Cu(II), 4 for Fe(III) and 4-5 for Pb(II). High sorption capacity was observed when compared with other conventional chelating polymers. The sorption kinetics was fairly rapid, as apparent from the loading half time t1/2 values, indicating a better accessibility of the chelating sites. 相似文献
6.
Renu Sharma Santosh K. Agarwal Shikha Rawat Meena Nagar 《Transition Metal Chemistry》2006,31(2):201-206
The synthesis and characterization of some transition metal cis-3,7-dimethyl-2,6-octadiensemicarbazone (CDOSC) complexes are reported. The ligand CDOSC yields: [ML2 Cl2] and [ML2 Cl2] Cl type complexes, where M = CrIII, MnII, FeIII, CoII, NiII, CuII, ZnII, CdII and HgII, L = CDOSC. Structures of the complexes were determined using elemental analysis, molar conductivity, magnetic measurements,
i.r. and electronic, as well as n.m.r spectra. CDOSC acts as a bidentate ligand in all the complexes. All the newly synthesized
metal complexes, as well as the ligand, were screened for their antibacterial activity. All the complexes exhibit strong inhibitory
action against Gram (+) bacteria Staphylococcus aureus and Gram (−) bacteria Escherichia coli. The antibacterial activities of the complexes are stronger than those of the ligand CDOSC itself. 相似文献
7.
Anil M. Shelke Varun Rawat Gurunath Suryavanshi Arumugam Sudalai 《Tetrahedron: Asymmetry》2012,23(22-23):1534-1541
A new enantioselective synthesis of two important fungal metabolites, (+)-stagonolide C and (?)-aspinolide A, has been described from readily available raw materials. Proline catalyzed asymmetric α-aminooxylation and Jorgensen’s epoxidation of aldehydes are the key reactions employed in the introduction of chirality. The formation of the 10-membered lactone core structure was finally accomplished via Steglich esterification and ring closing metathesis reactions. 相似文献
8.
Dwivedi Jyotsana Gupta Abhishek Verma Shikhar Paliwal Sarvesh Rawat Ajay Kumar Singh 《平面色谱法杂志一现代薄层色谱法》2019,32(2):103-108
JPC – Journal of Planar Chromatography – Modern TLC - A high-performance thin-layer chromatography (HPTLC) method for the simultaneous quantitative determination and validation of... 相似文献
9.
Eric Johnsen Johan Larsson Ankit V. Bhagatwala William H. Cabot Parviz Moin Britton J. Olson Pradeep S. Rawat Santhosh K. Shankar Bj?rn Sj?green H.C. Yee Xiaolin Zhong Sanjiva K. Lele 《Journal of computational physics》2010,229(4):1213-1237
Flows in which shock waves and turbulence are present and interact dynamically occur in a wide range of applications, including inertial confinement fusion, supernovae explosion, and scramjet propulsion. Accurate simulations of such problems are challenging because of the contradictory requirements of numerical methods used to simulate turbulence, which must minimize any numerical dissipation that would otherwise overwhelm the small scales, and shock-capturing schemes, which introduce numerical dissipation to stabilize the solution. The objective of the present work is to evaluate the performance of several numerical methods capable of simultaneously handling turbulence and shock waves. A comprehensive range of high-resolution methods (WENO, hybrid WENO/central difference, artificial diffusivity, adaptive characteristic-based filter, and shock fitting) and suite of test cases (Taylor–Green vortex, Shu–Osher problem, shock-vorticity/entropy wave interaction, Noh problem, compressible isotropic turbulence) relevant to problems with shocks and turbulence are considered. The results indicate that the WENO methods provide sharp shock profiles, but overwhelm the physical dissipation. The hybrid method is minimally dissipative and leads to sharp shocks and well-resolved broadband turbulence, but relies on an appropriate shock sensor. Artificial diffusivity methods in which the artificial bulk viscosity is based on the magnitude of the strain-rate tensor resolve vortical structures well but damp dilatational modes in compressible turbulence; dilatation-based artificial bulk viscosity methods significantly improve this behavior. For well-defined shocks, the shock fitting approach yields good results. 相似文献
10.
Zinc salicylaldimine complex immobilized on silica gel was used as a promising catalyst for the transesterification reaction of dimethyl terephthalate (DMT) and ethylene glycol (EG).The catalyst was characterized by Fourier transform infra‐red spectroscopy (FT‐IR), thermogravimetric analysis (TGA) and atomic absorption spectroscopy (AAS). The product bis‐(2‐hydroxyethyl)terephthalate (BHET)was confirmed by mass and 1H‐NMR studies. In comparison to zinc acetate i.e., homogeneous catalyst, a polymer supported catalyst showed better stability, catalytic activity and ease of separation from the reaction product. The catalyst can be reutilized during successive catalytic cycles. 相似文献