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121.
Six biflavones have been isolated from the leaf extracts of Araucaria bidwillii Hooker and Agathis alba Foxworthy; 7-O-methylcupressuflavone (2a) and 7,7″-di-O-methylagathisflavone (1c) are new compounds. The others are 7-O-methylagathisflavone (1a), 4?,7-di-O-methylagathisflavone (1b), 7,7″-di-O-methylcupressuflavone (2b) and bilobetin (3). In addition, the presence of several other biflavones has been indicated by TLC examination (Table 3). 相似文献
122.
Oxidative dehydrogenation of cyclohexane to benzene, catalyzed by copperchromia catalyst, has been carried out. Data was analyzed
according to the first order rate law. It is concluded that the rate is affected by changes in the volume flow rate due to
changes, in the value of the contact time as well as the distribution of the molecules transformed over a larger or smaller volume. 相似文献
123.
Saeed Ullah Jan Sami Ul Haq Syed Inayat Ali Shah Ilyas Khan Muhammad Atif Khan 《理论物理通讯》2019,71(6):647-657
This work is focused on the effect of heat and mass transfer with unsteady natural convection flow of viscous fluid along with ramped wall temperature under the assumption of the slip wall condition at the boundary. Analytical solutions are obtained by using Laplace transformation to the non-dimensional set of governing equations containing velocity, temperature and concentration. Moreover, the expression for skin-friction is derived by differentiating the analytical solutions of fluid velocity. Numerical tables for Skin-friction, Sherwood number and Nusselt-number are examined. For the physical aspects of the flow, we use various values of involved physical parameters such as Prandtl number (Pr), slip parameter ($\eta$), Schmidt number (Sc), buoyancy ratio parameter ($N$), Sherwood number (Sh), and time $(t)$. Additionally, the general solutions are plotted graphically and a comprehensive theoretical section of numerical discussions is included. 相似文献
124.
Usman Ilyas R.S. Rawat G. RoshanT.L. Tan P. LeeS.V. Springham Sam ZhangLi Fengji R. ChenH.D. Sun 《Applied Surface Science》2011,258(2):890-897
The structural and photoluminescence analyses were performed on un-doped and Mn doped ZnO thin films grown on Si (1 0 0) substrate by pulsed laser deposition (PLD) and annealed at different post-deposition temperatures (500-800 °C). X-ray diffraction (XRD), employed to study the structural properties, showed an improved crystallinity at elevated temperatures with a consistent decrease in the lattice parameter ‘c’. The peak broadening in XRD spectra and the presence of Mn 2p3/2 peak at ∼640 eV in X-ray Photoelectron Spectroscopic (XPS) spectra of the doped thin films confirmed the successful incorporation of Mn in ZnO host matrix. Extended near band edge emission (NBE) spectra indicated the reduction in the concentration of the intrinsic surface traps in comparison to the doped ones resulting in improved optical transparency. Reduced deep level emission (DLE) spectra in doped thin films with declined PL ratio validated the quenching of the intrinsic surface traps thereby improving the optical transparency and the band gap, essential for optoelectronic and spintronic applications. Furthermore, the formation and uniform distribution of nano-sized grains with improved surface features of Mn-doped ZnO thin films were observed in Field Emission Scanning Electron Microscopy (FESEM) images. 相似文献
125.
Mohammad Ilyas Maqsood Ahmad Malik E. H. Al-Mossalamy 《Journal of Dispersion Science and Technology》2013,34(1):50-56
Diperiodatoargentate(III) (DPA) was used as an oxidizing titrant in the spectrophotometric degradation of D-galactose for the first time. The kinetics is based on the reduction of silver(III) to silver(I) by D-galactose at specified experimental conditions. Effects of added [H+] and [periodate] have also been investigated. The premicellar environment of cetyltrimethylammonium bromide (CTAB) and sodiumdodecyl sulphate (SDS) strongly inhibits the reaction rate. The observed rate constant is strongly affected by [CTAB] and [SDS] changes for [surfactant] <cmc. Surfactant concentration range above the cmc does not influence the reaction rate. The monoperiodatoargentate(III) ions act as an active oxidant in comparison to that of DPA. A suitable mechanism involving a two-electron transfer from D-galactose to the silver(III) species has been proposed and hence a corresponding rate equation has been derived. 相似文献
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