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81.
Sensing of Pyrophosphate Anion by a Fluorescent Zn(II) Complex Bearing Acenaphthene Imidazole Moiety
Kavitha Venkatachalam Chitra Krishnamoorthy Gomathi Asaithambi Dhivya Rajasekaran Viswanathamurthi Periasamy 《Journal of Analytical Chemistry》2022,77(7):882-892
Journal of Analytical Chemistry - Acenaphthene imidazole ligand (AIMP) reacted with zinc acetate for the synthesis of Zn-AIMP complex which was used to detect pyrophosphate (PPi) ions in the... 相似文献
82.
Nagarajan Fedal Castro Kannaiyan Sathish Kumar Boobalan Chitra 《Journal of Thermal Analysis and Calorimetry》2022,147(10):5589-5598
Journal of Thermal Analysis and Calorimetry - High performance cooling anticipated in smaller size heat transfer equipment is the most significant challenge in many industries including CPU... 相似文献
83.
Bharat Bhooshan Sharma Chitra Murli Surinder M. Sharma 《Journal of Raman spectroscopy : JRS》2013,44(5):785-790
Acrylamide (C3H5NO), a hydrogen‐bonded amide, is an important compound from the point of view of basic and material research. It can be used as a model system for studying hydrogen bonding interactions in amides under pressure. As it is a monomer of polyacrylamide, an important polymer, high pressure investigation of polymerization in this material is also of interest. Our in‐situ high pressure Raman spectroscopic investigations of acrylamide carried out up to 17 GPa under quasi‐hydrostatic conditions indicate possible structural variations through the reconstruction of the N‐H‐‐‐O hydrogen bonds at pressures above 2.6 GPa. Emergence of several new spectral features at higher pressures indicate onset of polymerization. The characteristic polymer band becomes discernible at ~17 GPa. The increase in the relative intensity of the polymer peaks with respect to the monomer peaks on release to ambient conditions suggests that higher fraction of polymer is obtained on decompression. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
84.
R. Saravanan D. Rajesh S.V. Rajasekaran R. Perumal M. Chitra R. Jayavel 《Crystal Research and Technology》2013,48(1):22-28
Lead free piezoelectric single crystals of sodium potassium niobate (K0.5Na0.5)NbO3 (KNN) were grown by high‐temperature solution method using two different fluxes; one with a mixture of NaF and KF and other with addition of B2O3 along with the mixture. In the present study, the growth of KNN crystals without B2O3 flux and the same with B2O3 flux were compared. It was found that additions of small amounts of B2O3 lowered the melting temperature of the solid solution and enabled better dielectric properties. Phase analysis showed that all samples were crystallized in pure orthorhombic perovskite phase. AFM morphological studies showed that the addition of B2O3 flux increased the roughness of the grown crystal. Further, addition of B2O3 flux slightly decreased the orthorhombic to tetragonal phase transition temperature T(O—T) and the Curie temperature TC. The ferroelectric behaviour of KNN single crystal has been investigated at room temperature. The crystal grown using B2O3 flux exhibited a remanent polarization (Pr) ∼ 32 μC/cm2 and coercive field (Ec) of ∼11.8 kV/cm whereas the crystal grown without the use of B2O3 flux had a remanent polarization (Pr) ∼ 36 μC/cm2 and coercive field (Ec) of ∼14.6 kV/cm. 相似文献
85.
The optically active tetracyclic ketone 8 was converted into the pentacylic core 14 of the C-19 methyl substituted N(a)-H sarpagine and ajmaline alkaloids via a critical haloboration reaction. The ketone 14 was then employed in the total synthesis of 19(S),20(R)-dihydroperaksine-17-al (1) and 19(S),20(R)-dihydroperaksine (2). The key regioselective hydroboration and controlled oxidation-epimerization sequence developed in this approach should provide a general method to functionalize the C(20)-C(21) double bond in the ajmaline-related indole alkaloids. 相似文献
86.
The essential oil composition of Feronia elephantum Correa (family: Rutaceae) was examined by capillary gas chromatography (GC) and gas chromatography-mass spectroscopy (GC-MS). The analysis revealed the presence of 24 constituents, of which 18 constituents were identified. Trans-anethole (57.73%) and methyl chavicol (37.48%) were the major compounds, while cis-anethole, p-anisaldehyde, (E)-jasmone, methyl eugenol, β-caryophyllene, linalool and (E)-methyl isoeugenol were also present as the minor constituents. 相似文献
87.
S. Chitra R. Sudha S. Kalavathi A. G. S. Mani S. V. S. Rao P. K. Sinha 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(1):607-613
Crystalline silicotitanate inorganic ion exchanger, with a sitinakite structure is a candidate material for remediation of aqueous nuclear waste streams. Niobium substituted crystalline silicotitanates (Nb-CST) with varying concentrations of Nb (2, 4, 8, 12 and 24 mmol) and with constant concentrations of Ti-12 mmol, Si-16 mmol, Na-165 mmol were prepared hydrothermally and the products were characterized using techniques viz., XRD, SEM/EDS, DTA/TGA, surface area respectively. Batch experiments were carried out to study the kinetics of uptake of Cs137 and Sr90, to estimate the decontamination factor (DF) values and distribution coefficients (K d) for the above synthesized Nb-CST samples from actual radioactive waste solutions. The DF values for uptake of Cs and Sr by Nb-CST for the optimized Nb-concentration of 4 mmol after 24 h of equilibration was 355 and 136 respectively. The K d values for uptake of Cs and Sr for Nb-CST (Nb-4 mmol) after 24 h of equilibration was found to be 35,490 and 13,500 ml/g respectively. The ion exchange capacity of Nb-CST (Nb-4 mmol) towards Sr 90 and Cs137 was estimated to be 11.8 and 3.2 meq/g respectively. 相似文献
88.
89.
A transient haemodynamic study in a model cavopulmonary vascular system has been carried out for a typical range of parameters using a finite element‐based Navier–Stokes solver. The focus of this study is to investigate the influence of non‐Newtonian behaviour of the blood on the haemodynamic quantities, such as wall shear stress (WSS) and flow pattern. The computational fluid dynamics (CFD) model is based on an artificial compressibility characteristic‐based split (AC‐CBS) scheme, which has been adopted to solve the Navier–Stokes equations in space–time domain. A power law model has been implemented to characterize the shear thinning nature of the blood depending on the local strain rate. Using the computational model, numerical investigations have been performed for Newtonian and non‐Newtonian flows for different frequencies and input pulse forms. The haemodynamic quantities observed in total cavopulmonary connection (TCPC) for the above conditions suggest that there are considerable differences in average (about 25–40%) and peak (about 50%) WSS distributions, when the non‐Newtonian behaviour of the blood is taken into account. The lower WSS levels observed for non‐Newtonian cases point to the higher risk of lesion formation, especially at higher pulsation frequencies. A realistic pulse form is relatively safer than a sinusoidal pulse as it has more energy distributed in the higher harmonics, which results in higher average WSS values. The present study highlights the importance of including non‐Newtonian shear thinning behaviour for modelling blood flow in the vicinity of repaired arterial connections. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
90.
Ratnayake ND Wanninayake U Geiger JH Walker KD 《Journal of the American Chemical Society》2011,133(22):8531-8533
The stereochemistry of a phenylalanine aminomutase (PAM) on the andrimid biosynthetic pathway in Pantoea agglomerans (Pa) is reported. PaPAM is a member of the 4-methylidene-1H-imidazol-5(4H)-one (MIO)-dependent family of catalysts and isomerizes (2S)-α-phenylalanine to (3S)-β-phenylalanine, which is the enantiomer of the product made by the mechanistically similar aminomutase TcPAM from Taxus plants. The NH(2) and pro-(3S) hydrogen groups at C(α) and C(β), respectively, of the substrate are removed and interchanged completely intramolecularly with inversion of configuration at the migration centers to form β-phenylalanine. This is a contrast to the retention of configuration mechanism followed by TcPAM. 相似文献