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131.
Karthikeyan B Pandiyarajan T Mangaiyarkarasi K 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,82(1):97-101
Optical properties of Ca doped ZnO nanoparticles prepared at room temperature through wet chemical method have been investigated. X-ray diffraction studies show that particles are crystalline in nature and doping did not induce impurity phases. Optical absorption measurements show an absorption peak at ∼372 nm which is due to excitonic absorption of the ZnO. Photoluminescence studies reveal a broad emission at an excitation wavelength of 335 nm and the bands are attributed to near band edge emission, oxygen vacancies, surface dangling bonds and zinc interstitials. Incorporating Ca2+ induces reduction in near band edge emission and there is an enhancement in the oxygen vacancy peaks which are attributed to the shape changes in the nanoparticles. 相似文献
132.
The crystal structure of p-[N,N-bis(2-chloroethyl)amino]benzaldehyde-4-phenyl thiosemicarbazone(CEAB-4-PTSC) is described. The compound crystallizes in the monoclinic crystal system, P21/c space group, Z = 4, calculated density = 1.327 mg/cm3, V = 1978.2(6) ?3 with unit cell parameters a = 16.240(3) ?, b = 12.821(2) ?, c = 9.8543(16) ?, ?? = 105.382(6)°. The crystal structure reveals that the compound exists in the thione form and S1 and N2 are at trans-conformation to each other with respect to the N3-C12 bond. The packing of molecules in the crystal lattice is stabilized by intramolecular hydrogen bonds. 相似文献
133.
S. Parthiban H. Anandalakshmi S. Senthilkumar V. Karthikeyan S. C. Mojumdar 《Journal of Thermal Analysis and Calorimetry》2012,108(3):881-885
We have prepared pure and divalent vanadyl ion-doped magnesium rubidium sulfate hexahydrate crystals by using slow evaporation solution growth technique. It is interesting to observe that Vo(II) doping influences the physical properties of MRSH. Presence of Vo(II) ions in the doped specimen was confirmed by energy dispersive spectroscopy and electron paramagnetic resonance spectroscopy. FTIR studies reveal that the doping of vanadium ion has not altered the basic structure of MRSH. Scanning electron microscope studies of doped sample reveals that structure defect centers are formed in the crystals. Gradual decomposition patterns were observed for pure and doped specimens in thermogravimetry and differential thermogravimetry. The grown crystals were also characterized by powder X-ray diffraction. The second harmonic generation efficiency tested using Kurtz powder technique is not influenced by the added dopant. 相似文献
134.
S Amaresh GJ Kim K Karthikeyan V Aravindan KY Chung BW Cho YS Lee 《Physical chemistry chemical physics : PCCP》2012,14(34):11904-11909
Lithium cobalt fluorophosphate, Li(2)CoPO(4)F, is successfully synthesized by a solid state reaction under Ar flow at 700 °C. X-ray diffraction and scanning electron microscopic studies are utilized to analyze the structural and morphological features of the synthesized materials, respectively. The presence of fluorine is also supported by energy-dispersive X-ray spectroscopy. The electrochemical properties are evaluated by means of Li/Li(2)CoPO(4)F half-cell configurations in both potentiostatic and galvanostatic modes. The Li/Li(2)CoPO(4)F cell delivers an initial discharge capacity of 132 mA h g(-1) at a current density of 0.1 mA cm(-2) between 2.0 and 5.1 V at room temperature. Due to the higher operating potential of the Co(2+/3+) couple in the fluorophosphate matrix, this cell shows a capacity retention of only 53% after 20 cycles, still the material delivered 108 mA h g(-1) at a high current rate of 1 C. Cyclic voltammetric studies corroborate the insertion and extraction of Li(+) ions by a single phase reaction mechanism during cycling. 相似文献
135.
Ramachandran G Karthikeyan NS Giridharan P Sathiyanarayanan KI 《Organic & biomolecular chemistry》2012,10(28):5343-5346
A simple and efficient three components domino reaction of γ-butyrolactam (2-pyrrolidinone), aromatic aldehyde and substituted thiophenol catalyzed by elemental iodine resulted in the formation of 1-((phenylthio)(phenyl)methyl)pyrrolidin-2-one derivatives. The stability of the synthesized analogues was evaluated in stimulated gastric fluid (SGF) and bovine serum albumin (BSA). In vitro anticancer activity was investigated in the low micromolar range and a few analogues were found to possess good activity. This current protocol provides several advantages like shorter reaction time, excellent yield and convenient work-up. 相似文献
136.
Highly important trans-3,4-dihydro-2H-1,4-benzoxazine moieties were easily synthesized by domino aziridine ring opening with o-bromophenols and o-chlorophenols followed by the palladium catalyzed coupling-cyclization (intramolecular C(aryl)–N(amide) bond formation) with good to excellent yields. 相似文献
137.
Jenna M. Len Noor Hussein Saloni Malla Kyle Mcintosh Rahul Patidar Manivannan Elangovan Karthikeyan Chandrabose N. S. Hari Narayana Moorthy Manoj Pandey Dayanidhi Raman Piyush Trivedi Amit K. Tiwari 《Molecules (Basel, Switzerland)》2021,26(14)
In this study, we designed, synthesized and evaluated, in vitro, novel chalcone analogs containing dialkylamino pharmacophores in the cervical cancer cell line, OV2008. The compound, DML6 was selective and significantly decreased the proliferation of OV2008 and HeLa cells in sub-micromolar concentrations, compared to prostate, lung, colon, breast or human embryonic kidney cell line (HEK293). DML6, at 5 μM, arrested the OV2008 cells in the G2 phase. Furthermore, DML6, at 5 μM, increased the levels of reactive oxygen species and induced a collapse in the mitochondrial membrane potential, compared to OV2008 cells incubated with a vehicle. DML6, at 5 μM, induced intrinsic apoptosis by significantly (1) increasing the levels of the pro-apoptotic proteins, Bak and Bax, and (2) decreasing the levels of l the anti-apoptotic protein, Bcl-2, compared to cell incubated with a vehicle. Furthermore, DML6, at 5 and 20 μM, induced the cleavage of caspase-9, followed by subsequent cleavage of the executioner caspases, caspase-3 and caspase-7, which produced OV2008 cell death. Overall, our data suggest that DML6 is an apoptosis-inducing compound that should undergo further evaluation as a potential treatment for cervical cancer. 相似文献
138.
Jesus M. Munoz-Pacheco Christos Volos Fernando E. Serrano Sajad Jafari Jacques Kengne Karthikeyan Rajagopal 《Entropy (Basel, Switzerland)》2021,23(7)
In this paper, the stabilization and synchronization of a complex hidden chaotic attractor is shown. This article begins with the dynamic analysis of a complex Lorenz chaotic system considering the vector field properties of the analyzed system in the domain. Then, considering first the original domain of attraction of the complex Lorenz chaotic system in the equilibrium point, by using the required set topology of this domain of attraction, one hidden chaotic attractor is found by finding the intersection of two sets in which two of the parameters, r and b, can be varied in order to find hidden chaotic attractors. Then, a backstepping controller is derived by selecting extra state variables and establishing the required Lyapunov functionals in a recursive methodology. For the control synchronization law, a similar procedure is implemented, but this time, taking into consideration the error variable which comprise the difference of the response system and drive system, to synchronize the response system with the original drive system which is the original complex Lorenz system. 相似文献
139.
K. Karthikeyan S. Amaresh D. Kalpana R. Kalai Selvan Y.S. Lee 《Journal of Physics and Chemistry of Solids》2012,73(2):363-367
Hierarchical structured Co-doped SnO2 nanoparticles are prepared by a low temperature hydrothermal process. The structural and surface morphologies of the SnO2 and Sn1?xCoxO2 nanoparticles are studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The Sn1?xCoxO2 nanoparticles form with a tetragonal rutile structure during the hydrothermal process without further calcination. The pseudocapacitance behavior of the Sn1?xCoxO2 nanoparticles is characterized by cyclic voltammetry (CV) in 1.0 M H2SO4 electrolyte. The specific capacitance (SC) is found to increase with an increase in cobalt content. A maximum SC of 840 F g?1 is obtained for a Sn0.96Co0.04O2 composite at a 10 mV s?1 scan rate. 相似文献
140.
The desulfurization reaction introduced by Yan and Dawson as a postnative chemical ligation step greatly expanded the scope of ligation chemistry beyond Xaa-Cys (Xaa is any amino acid) by making ligation at Xaa-Phe, Xaa-Val, Xaa-Lys, Xaa-Leu, Xaa-Thr, and Xaa-Pro junctions accessible in the synthesis of functional proteins. A new ligation site based on Xaa-Gln utilizing γ-mercaptoglutamine is reported, and several examples on the efficiency of ligation coupled with desulfurization are provided. 相似文献