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排序方式: 共有145条查询结果,搜索用时 15 毫秒
71.
M. Kondaiah D. Sravana Kumar K. Sreekanth D. Krishna Rao 《The Journal of chemical thermodynamics》2011,43(12):1844-1850
Ultrasonic velocities, u, densities, ρ, of binary mixtures of N,N-dimethyl formamide (DMF) with methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), and 2-ethyl hexyl acrylate (EHA), including pure liquids, over the entire composition range have been measured at T = 308.15 K. Using the experimental results, the excess molar volume, , partial molar volumes, , , and excess partial molar volumes, , have been calculated. Molecular interactions in the systems have been studied in the light of variation of excess values of calculated properties. The excess properties have been fitted to Redlich–Kister type polynomial and the corresponding standard deviations have been calculated. The positive values of indicate the presence of dispersion forces between the DMF and acrylic ester molecules. Further theoretical values of sound velocity in the mixtures have been evaluated using various theories and have been compared with experimental sound velocities to verify the applicability of such theories to the systems studied. Theoretical ultrasonic velocity data have been used to study molecular interactions in the binary systems investigated. 相似文献
72.
Ratnakaram YC Reddy AV Chakradhar RP 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2002,58(8):1809-1822
Spectroscopic properties of Er3+ ions in different chlorophosphate glasses 50P2O5-30Na2HPO4-19.8RCl (R = Li, Na, K, Ca and Pb) are studied. The direct and indirect optical band gaps (Eopt) and the various spectroscopic parameters (E1, E2, E3, and zeta4f and alpha) are reported. The oscillator strengths of the transitions in the absorption spectrum are parameterized in terms of three Judd-Ofelt intensity parameters (omega2, omega4 and omega6). These intensity parameters are used to predict the transition probabilities (A), radiative lifetimes (tauR), branching ratios (beta) and integrated cross sections (sigma) for stimulated emission. Attention has been paid to the trend of the intensity parameters over hypersensitive transitions and optical band gaps. The lifetimes and branching ratios of certain transitions are compared with other glass matrices. 相似文献
73.
Sreekanth J. Varma Jerin George P.P. Jeeju S. Jayalekshmi 《Journal of luminescence》2012,132(3):801-805
Polyaniline (PANI) is well-known for its remarkable electrical and optical properties which find immense applications in polymer optoelectronics. Though extensive work has been reported in polyaniline samples both in bulk and thin film forms, much attention has not been paid to investigate the quantum confinement effects in ultrathin polyaniline films. The present work is devoted to the search for quantum confinement effects in ultrathin polyaniline films having nanometer thickness, prepared from m-cresol, through conventional and less sophisticated spectroscopic techniques. Remarkable blue-shift has been observed in the absorption spectrum of these samples. Much intense photo-luminescent emission with considerable blue-shift observed in these ultrathin films is cited as the clear evidence for confinement effects. 相似文献
74.
75.
The synthesis of enantiopure 2-C-methyl-d-erythritol-4-phosphate is disclosed. A 1,3-diol possessing a quaternary stereogenic centre, prepared stereoselectively from an acyclic tri-substituted alkene, has been utilized as a key intermediate. 相似文献
76.
Sridevi Gorle Suresh Maddila Santosh Chokkakula Palakondu Lavanya Moganavelli Singh Sreekanth B. Jonnalagadda 《Journal of heterocyclic chemistry》2016,53(6):1852-1858
A new series of 5‐fluoro‐N4‐(3‐(4‐substitutedbenzylamino)phenyl)‐N2‐(4‐morpholinophenyl)pyrimidine‐2,4‐diamine derivatives ( 7a , 7b , 7c , 7d , 7e , 7f , 7g , 7h , 7i , 7j ) are prepared from using an intermediate compound 5‐fluoro‐N4‐(3‐(aminophenyl)‐N2‐(4‐morpholinophenyl)pyrimidine‐2,4‐diamine ( 5 ). The structures of the newly synthesized products are established from their spectral 1H‐NMR, 13C‐NMR, 19F‐NMR, ESI‐MS, and analytical data. Here we report the synthesized compounds and larvicidal activity. All the compounds are screened for their significant larvicidal activity against third instar larvae at 24, 48, and 78‐h time exposure, and values were compared with standard drug Malathion. The Compounds 7i , 7a , 7c , 7f , and 7j exhibited significant activity. However the compounds 7b , 7e , 7d , and 7h showed excellent activity when compared to the above compounds and to standard drug malathion too because of the presence of mild electron withdrawing groups such as trifluoro, fluorine, hydroxy, nitro, and methoxy derivatives which are attached to the benzyl ring. 相似文献
77.
Berelli Anupama Airva Aruna Vijjulatha Manga Sreekanth Sivan Madamsetty Vijay Sagar Ravula Chandrashekar 《Journal of fluorescence》2017,27(3):953-965
Ternary Cu(II) complexes [Cu(II)(L)(bpy)Cl] 1, [Cu(II)(L)(Phen)Cl] 2 [L = 2,3–dimethyl-1-phenyl-4(2 hydroxy-5-methyl benzylideneamino)-pyrazol-5-one, bpy = 2,2′ bipyridine, phen =1,10 phenanthroline) were synthesized and characterized by elemental analyses, UV-Visible, FT-IR, ESR, Mass, thermogravimetric and SEM EDAX techniques. The complexes exhibit octahedral geometry. The interaction of the Cu(II) with cailf thymus DNA (CT-DNA) was explored by using absorption and fluorescence spectroscopic methods. The results revealed that the complexes have an affinity constant for DNA in the order of 104 M?1 and mode of interaction is intercalative mode. The DNA cleavage study showed that the complexes cleaved DNA without any external agent. The interaction of Cu(II) complexes with bovine serum albumin (BSA) was also studied using absorption and fluorescence techniques. The cytotoxic activity of the Cu(II) complexes was probed in HeLa (human breast adenocarcinoma cell line), B16F10 (Murine melanoma cell line) and HEPA1–6 celllines, complex 1 has good cytotoxic activity which is comparable with the doxarubicin drug, with IC50 values ranging from 3 to 12.6 μM. A further molecular docking technique was employed to understand the binding of the complexes towards the molecular target DNA. Investigation of the antioxidative properties showed that the metal complexes have significant radical scavenging activity potency against DPPH radical. 相似文献
78.
MK Hossain-Ibrahim K Rezajooi JK MacNally MRJ Mason AR Lieberman PN Anderson 《BMC neuroscience》2006,7(1):8-21
Background
Inflammation around cell bodies of primary sensory neurons and retinal ganglion cells enhances expression of neuronal growth-associated genes and stimulates axonal regeneration. We have asked if inflammation would have similar effects on corticospinal neurons, which normally show little response to spinal cord injury. Lipopolysaccharide (LPS) was applied onto the pial surface of the motor cortex of adult rats with or without concomitant injury of the corticospinal tract at C4. Inflammation around corticospinal tract cell bodies in the motor cortex was assessed by immunohistochemistry for OX42 (a microglia and macrophage marker). Expression of growth-associated genes c-jun, ATF3, SCG10 and GAP-43 was investigated by immunohistochemistry or in situ hybridisation. 相似文献79.
80.