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81.
P. Thiyagarajan Brajesh Tiwari M. Kottaisamy N. Rama M. S. Ramachandra?Rao 《Applied Physics A: Materials Science & Processing》2009,94(3):607-612
Cool white light was realized in Y2−x−y
Gd
x
SiO5: Ce
y
phosphor under near UV excitation, due to the occupation Ce3+ in Y3+ 1st and 2nd site, synthesized using solid state carbothermal reduction route. SEM with elemental analysis show the existence
of Gd in Y2SiO5:Ce enhances the particles size in comparison to Y2SiO5:Ce phosphors alone. Gd3+ (0.00≤x≤0.75) and Ce3+ (0.02≤y≤0.10) concentration was optimized to 0.50 and 0.08 in Y2SiO5, respectively. The CIE chromaticity color coordinates (0.24, 0.20) are close to cool white light value which could be useful
for the fabrication of cool white LED. 相似文献
82.
The phase boundary of the binary liquid system CS2+CH3NO2 is studied over nearly six decades in reduced temperature 3×10−6<ε=(T
C−T)/T
C<2×10−1 and over the composition range 8-98 mole % of CS2. The critical parameters areT
C=335.132K andx
C=57.34 mole % of CS2. A single critical exponentβ=0.315±0.004 fits the observations over the entire range with no indication ofβ increasing to the classical value of 1/2 far away fromT
C. The diameter of the coexistence curve shows a rectilinear behaviour only far away fromT
C. NearT
C, the deviation ΔX from the rectilinear law seems to fit a curve of the form ΔX=fε7/8 exp (−gε
h), the derivative of which has a singularity like that of specific heat. An ambiguity in the analysis of the data in terms
of mole fractions and volume fractions is pointed out. It is also suggested that the curvature of the diameter may be much
weaker in a liquid-gas system and hence might have escaped detection. 相似文献
83.
The cylindrical approximation originally proposed by Pippard for the λ-transitions in one-component systems is extended to multicomponent systems. The application of the generalised Pippard relations to binary liquid mixtures is considered. The relations for He3 + He4 mixtures are shown to be equivalent to those obtained by earlier workers. The validity of the relation relating specific heat and thermal expansion for binary liquid systems is discussed on the basis of the measurements performed on the system methaonl +n-heptane. Lack of information on the behaviour of a few quantities prevents a quantitative test of the relation. 相似文献
84.
A. Ramachandra Rao Rathna Devanathan 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1973,24(2):203-213
Summary The pulsatile flow of an incompressible viscous fluid in a cylindrical tube of varying cross section is investigated for small Reynolds numbers. The solutions consist of a stedy and an oscillatory part. The shear stress distribution on the wall is evaluated and discussed in detail for special geometries like tapered tubes, locally constricted tubes and peristaltic tubes. The existence of separation in the flow field is noticed.
Zusammenfassung Es wird die pulsierende Strömung einer zähen inkompressiblen Flüssigkeit in Rohren mit veränderlichem Querschnitt bei kleinen Reynoldsschen Zahlen untersucht. Die Lösungen bestehen aus einem stationären und einem oszillatorischen Anteil. Die Schubspannungsverteilung an den Rohrwänden wird für einige besondere geometrische Rohrformen wie konische Rohre, örtlich eingeschnürte Rohre und peristaltische Rohre berechnet und ausführlich diskutiert. Bei einigen Fällen wird die Existenz einer Ablösung im Strömungsfeld festgestellt.相似文献
85.
Lolakshi Mahesh Kumar Praveen Mishra Badekai Ramachandra Bhat 《Journal of Saudi Chemical Society》2019,23(3):307-314
We report the synthesis of Fe-NCN pincer complex as homogenous catalyst and its composite by immobilizing the complex on amino functionalized graphene oxide as a heterogeneous catalyst for Suzuki coupling reactions. Both the complex and the composite were employed in catalyzing the Suzuki-Miyaura cross-coupling reaction between the aryl halide and phenyl boronic acid in acetonitrile solvent media with Cs2CO3 as a base. Effect of substitution over aryl halide was also investigated. Immobilization of the pincer complex had advantageous recovery and reuse of the catalyst as compared to its homogenous analog with no significant decrease in the catalytic efficiency. 相似文献
86.
Kong WM Chik Z Ramachandra M Subramaniam U Aziddin RE Mohamed Z 《Molecules (Basel, Switzerland)》2011,16(9):7344-7356
The extract from Mitragyna speciosa has been widely used as an opium substitute, mainly due to its morphine-like pharmacological effects. This study investigated the effects of M. speciosa alkaloid extract (MSE) on human recombinant cytochrome P450 (CYP) enzyme activities using a modified Crespi method. As compared with the liquid chromatography-mass spectrometry method, this method has shown to be a fast and cost-effective way to perform CYP inhibition studies. The results indicated that MSE has the most potent inhibitory effect on CYP3A4 and CYP2D6, with apparent half-maximal inhibitory concentration (IC(50)) values of 0.78 μg/mL and 0.636 μg/mL, respectively. In addition, moderate inhibition was observed for CYP1A2, with an IC(50) of 39 μg/mL, and weak inhibition was detected for CYP2C19. The IC(50) of CYP2C19 could not be determined, however, because inhibition was <50%. Competitive inhibition was found for the MSE-treated CYP2D6 inhibition assay, whereas non-competitive inhibition was shown in inhibition assays using CYP3A4, CYP1A2 and CYP2C19. Quinidine (CYP2D6), ketoconazole (CYP3A4), tranylcypromine (CYP2C19) and furafylline (CYP1A2) were ACCESSused as positive controls throughout the experiments. This study shows that MSE may contribute to an herb-drug interaction if administered concomitantly with drugs that are substrates for CYP3A4, CYP2D6 and CYP1A2. 相似文献
87.
Naeem B. Hanna Ramachandra V. Joshi Steven B. Larson Roland K. Robins Ganapathi R. Revankar 《Journal of heterocyclic chemistry》1989,26(6):1835-1843
Several substituted 1-β-D-ribofuranosyl-1,2-dihydro-2-oxopyridines have been prepared as congeners of nicotinamide ribonucleoside. Direct glycosylation of the silylated 3-ethylcarboxylate 5 or 3-carbamoyl 6 derivative of 1,2-dihydro-2-oxopyridine with 1,2,3,5-tetra-O-acetyl-β-D-ribofuranose ( 7 ) in the presence of trimethylsilyl triflate gave the corresponding blocked nucleosides 8 and 9 , respectively in good yield. Ammonolysis of 8 and 9 with methanolic ammonia furnished 1-β-D-ribofuranosyl-1,2-dihydro-2-oxopyridine-3-carboxa-mide ( 10 ), the structure of which was established by single-crystal X-ray diffraction analysis. Thiation of 9 with Lawesson's reagent and subsequent deacetylation of the thiated product 11 with methanolic ammonia furnished 1-β-D-ribofuranosyl-1,2-dihydro-2-oxopyridine-3-thiocarboxamide ( 12 ). Modification of the carbo-nitrile function of 1-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)-1,2-dihydro-2-oxopyridine-4-carbonitrile ( 13 ) gave a series of 4-substituted-1-β-D-ribofuranosyl-1,2-dihydro-2-oxopyridines, in which the 4-substituent is a thiocarboxamide 15 , carboxamide 16 , carboxamidoxime 17 , carboxamidine 18 and aminomethyl 19 group. None of these compounds exhibited any significant antitumor or antiviral effects in vitro. 相似文献
88.
A.S.R. Anjaneyulu P.Atchuta Ramaiah L.Ramachandra Row R. Venkateswarlu A. Pelter R.S. Ward 《Tetrahedron》1981,37(21):3641-3652
The isolation and characterisation of five new compounds and nine known compounds from the heartwood of Cleistanthus collinus are reported. The new compounds are wodeshiol 16,3,4-dihydrotaiwanin C 20, and three new glycosides 24, 25 and 26 of diphyllin and taiwanin E The 1H and 13C NMR spectra of these compounds are also reported. 相似文献
89.
An indirect complexometric method is described for the determination of cadmium(II), 1,10-phenanthroline being used as masking agent. Cadmium(II) in a given sample solution is initially complexed with an excess of EDTA and the surplus EDTA is titrated with lead nitrate solution at pH 5.0–6.0 (hexamine), using xylenol orange as indicator. An excess of 1,10-phenanthroline is then added and the EDTA released from the Cd-EDTA complex is titrated with standard lead nitrate solution. Results are obtained for 1.5–57 mg of Cd with relative errors 0.90% and standard deviations 0.06 mg. Cu(II), Co(II), Hg(II), Ni(II), Zn(II), Pd(II), Tl(III), Au(III) and Sn(IV) interfere, but can be easily masked. The method is applied for the determination of cadmium in synthetic alloy solutions. 相似文献
90.