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91.
An interpretation of the Raman data of the organic superconductor (BEDT-TTF)2
I
3 is given, based on the modified charge bag model for superconductivity. The Raman intensities are calculated at zero temperature both in the normal as well as the superconducting (SC) states. The scattering due to charge carriers as well as the phonons are taken into account. The results show a constant intensity background which reduces on going from the normal to the superconducting state. Similarly, the loss of intensity, broadening and softening of the frequency of a low lying phonon on going from the normal to the SC state are predicted. All these features are in qualitative agreement with the observed Raman data. 相似文献
92.
R. Padhee Piyush R. Das B.N. Parida S. Behera R.N.P. Choudhary 《Current Applied Physics》2013,13(6):1014-1020
Using high temperature solid state reaction the polycrystalline sample of K2Pb2Dy2W2Ti4Ta4O30 was prepared. Single-phase compound formation was confirmed by preliminary X-ray structural analysis. The surface morphology recorded by scanning electron microscope at room temperature exhibits a dense uniform grain distribution on the surface of the sample. Ferroelectricity in the material is confirmed by the variation of polarization with temperature. The temperature and frequency dependence of electrical parameters (impedance, modulus, conductivity, etc.) of the material exhibits a strong correlation with its microstructure (i.e., bulk, grain boundary, etc.) and electrical properties. A typical Arrhenius behavior was observed in the temperature dependence of dc conductivity. The nature of frequency dependence of ac conductivity obeys Jonscher's universal power law. The variation of current with temperature shows that the material has high pyroelectric coefficient and figure of merit, thus making it useful for pyroelectric sensors with working temperature upto 500 °C. 相似文献
93.
Solubilizing C60 molecules in an aqueous medium is highly imperative in processing them in different forms of ionic or nonionic liquids, nanofluids, films and other derivatives. In this investigation, we report a facile chemical route using polymer molecules of poly(vinyl pyrrolidone) (PVP) which mediate C60 molecules dissolving in water in a stable solution at room temperature. Poly(vinyl pyrrolidone) molecules, soluble in water as well as many organic liquids such as n-butanol, ethanol, or DMF, can be useful for transferring C60 molecules from a non-aqueous to an aqueous system. A broad optical absorption arises over 270–520 nm when C60 molecules are dissolved in water, 0.001–0.065 g/L in presence of 20–120 g/L PVP molecules. It consists of a strong π → π* absorption band (relatively sharp) lying at 294 nm in C(sp2) electrons from PVP-surface modified C60 molecules followed by a broad charge transfer band which extends up to 520 nm. Upon a suitable surface modification, the C60 molecules conquer enhanced optical absorption in both kinds of the bands. Dynamic light scattering reveals an average hydrodynamic length 181.5 nm and a polydispersity index 0.506 after a typical loading 0.065 g/L C60. A zeta potential ?8.3 mV with a surface conductivity 0.064 mS/cm at 6.5 pH describes a negatively charged surface structure, showing an n-electron transfer from C=O (PVP) to a nanosurface in surface modified C60 molecules in a weak donor–acceptor complex. Water soluble C60 in presence of a biocompatible compound like PVP is useful for biological, medicinal, and other applications. 相似文献
94.
A novel solid acid catalyst has been extensively used for the esterification reaction. Herein, tungstate promoted vanadium phosphate material is fabricated from its precursor, VOHPO(4)·0.5H(2)O and its catalytic activities and structure are investigated in detail. This kind of catalyst is, for the first time, applied for the effective production of biodiesel from fatty acids. Although vanadium phosphate has been extensively used in gas phase oxidation reactions, it has not drawn much attention for its application in liquid phase reactions. Our recent results indicate that vanadium phosphate is an effective, minimally polluting and re-usable catalyst that is highly suited to the production of biodiesel from fatty acids. This work extends the possibility of using VPO in other liquid phase reactions. 相似文献
95.
S.N. Behera B.K. Patel G.V.R. Prasad S. Chakravarty R. Mythili M. Vijaylakshmi 《Phase Transitions》2013,86(1-2):133-142
A low energy cluster beam deposition (LECBD) technique has been used to prepare the Sb cluster films on different substrates and are characterized using a variety of probes. Proton induced X-ray emission (PIXE) analysis shows the absence of any foreign trace elemental impurity even at ppm level. Glancing angle X-ray diffraction (GXRD) and transmission electron diffraction (TED) studies reveal the presence of single crystalline feature of Sb with hexagonal symmetry along with Sb-oxides. The transmission electron micrograph (TEM) of the cluster films of thickness 20 Å and 100 Å show size distribution which is more for the 100 Å film compared to that of the 20 Å one. The photoluminescence (PL) studies at 300 K show red shifted peaks along with the one possibly due to HOMO-LUMO transition around 2.4 eV. X-ray photoelectron spectroscopy (XPS) of Sb cluster films show shoulders to the core level peaks of the Sb corresponding to 3d 3/2 and 3d 5/2 which are shifted by 1.0 to 2.0 eV suggesting the formation of Sb-oxide. Raman scattering studies show the shift of A 1g and E g vibrational modes from their bulk value. 相似文献
96.
Jagannath Panigrahi Bijan B. Nayak Debadhyan Behera Umakanta Subudhi Bhabani S. Acharya 《Applied Physics A: Materials Science & Processing》2012,108(3):577-585
Nano ZnO thin films were deposited on thin Al foils by a rf glow discharge plasma method in which sublimed zinc acetate vapor (precursor) reacted with oxygen plasma inside a low-pressure reactor. The films were microstructurally characterized using XRD, TEM, FESEM, optical reflectance and micro-Raman spectroscopy methods. In view of the good scope of ZnO coating in food packaging, the antibacterial activity in the ZnO thin films was studied by exposing the films to E. coli and P. aeruginosa for up to 8 h. Bacterial cell inhibition of up to 98–99 % was observed in the thin films. 相似文献
97.
Biswajit Mallick Ramesh Chandra Behera Simanchal Panigrahi Tanmaya Badapanda Biswanath Parija Banita Behera Manas Panigrahi Madhumita Sarangi 《Indian Journal of Physics》2009,83(4):525-529
Electron microscopy is an important characterization technique for the study of textile fibre as it gives more information
on fabric wear, nature of fibre fracture, chemical degradation, abrasion, fatigue and many others. Electron Probe Micro Analyzer
(EPMA) micrographs of virgin and some neutron-irradiated samples (graphite coated) are discussed. The filament diameter, D, of virgin PET fibre obtained from EPMA study was 12.5 μn. The surface topography of single filament distinctly reveals the
core and sheath parts of the filament. The core diameter of the virgin fibre was estimated to be 1.43 μm. The fibre irradiated
at fluence 1 × 1012 n/cm2 shows radiation induced sphere like polymer balls or spherulites of diameter 2.27 μm in the expanded core region. Due to
irradiation, the sheath area crosslinks with expanded core region, which may be responsible for increase of strength and hardness
of the polymer materials. Moreover, the micrograph at 3000 X magnifications clearly shows that there is no preferred orientation
of the polymer in any direction confirming the isotropic nature of the sample.
相似文献
98.
S. Mahadevan S.P. Behera G. Gnanaprakash T. Jayakumar J. Philip B.P.C. Rao 《Journal of Physics and Chemistry of Solids》2012,73(7):867-872
We use the Fourier transform based Warren–Averbach (WA) analysis to separate the contributions of X-ray diffraction (XRD) profile broadening due to crystallite size and microstrain for magnetic iron oxide nanoparticles. The profile shape of the column length distribution, obtained from WA analysis, is used to analyze the shape of the magnetic iron oxide nanoparticles. From the column length distribution, the crystallite size and its distribution are estimated for these nanoparticles which are compared with size distribution obtained from dynamic light scattering measurements. The crystallite size and size distribution of crystallites obtained from WA analysis are explained based on the experimental parameters employed in preparation of these magnetic iron oxide nanoparticles. The variation of volume weighted diameter (Dv, from WA analysis) with saturation magnetization (Ms) fits well to a core shell model wherein it is known that Ms=Mbulk(1?6g/Dv) with Mbulk as bulk magnetization of iron oxide and g as magnetic shell disorder thickness. 相似文献
99.
P. Mallick Chandana Rath J. K. Dash R. Biswal D. C. Agarwal D. Behera D. K. Avasthi D. Kanjilal P. V. Satyam N. C. Mishra 《Indian Journal of Physics》2010,84(10):1399-1404
NiO thin films grown on Si(100) substrates by electron beam evaporation, were sintered at 500 °C and 700 °C. The films were
irradiated with 120 MeV Au9+ ions. Irradiation had different effects depending upon the initial microstructure of the films. Irradiation of the films
at a fluence of 3 × 1011 ions cm−2 leads to grain growth for the films sintered at 500 °C and grain fragmentation for the films sintered at 700 °C. At still
higher fluences of irradiation, grain size in 500 °C sintered film decreased, but the same improved in 700 °C sintered film.
Associated with the grain size, texturing of the films was also shown to undergo significant modifications under irradiation. 相似文献
100.
Ashok Behera Kakali De Susmita Chandra Sankha Chattopadhyay Mridula Misra 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(1):123-129
In vivo imaging of tumours using radiolabelled somatostatin (SST) analogues has become an accepted clinical tool in oncology.
HYNIC-Tyr3 octreotide and Tyr3 octreotide were synthesized by FMOC solid-phase peptide synthesis using a semi-automated synthesizer. These were analyzed
and purified by RP-HPLC, mass spectroscopy, IR spectroscopy, 1H NMR and 13C NMR. The prochelator 6-BOC-HYNIC was also synthesised and characterised indigenously. HYNIC-Tyr3 octreotide was labelled with 99mTc using Tricine and EDDA as coligand by SnCl2 method. Labelling with 99mTc was performed at 100 °C for 15 min and radiochemical analysis by ITLC and HPLC methods. The radiochemical purity of the
complex was over 98% and log p value was found to be −1.27 ± 0.12. The stability of radiolabelled peptide complex was checked at 37 °C up to 24 h. Blood
clearance and protein-binding study was also performed. In vivo biodistribution studies in rat showed uptake of 99mTc-HYNIC-TOC in kidney than any other organs. The blood clearance was faster with rapid excretion through kidneys and relatively
low uptake in liver. 相似文献