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961.
Animesh PatraSandipan Sarkar Titas MukherjeeEnnio Zangrando Pabitra Chattopadhyay 《Polyhedron》2011,30(17):2783-2789
Zinc(II) complexes of the formula [Zn(L)(X)2] (where X = Cl−, N3−, NCO− and SCN− (1a-d, respectively)) and {[Zn(L)(ClO4)(H2O)](ClO4)}n (2), were isolated in the pure form on the reaction of 1,3-bis(2-pyridylmethylthio)propane (L) with different zinc(II) salts. All the complexes were characterized by physicochemical and spectroscopic tools. The X-ray crystallographic analyses of the complexes 1d and 2 showed that the former is mononuclear while complex 2 is a 1D coordination polymer, {[Zn(L)(ClO4)(H2O)](ClO4)}n, due to a different coordination mode of the tetradentate ligand L. The zinc(II) ions present an octahedral coordination geometry in both compounds, which is more distorted in the mononuclear complex 1d. The study indicates that the counter anion of the zinc(II) salt used as reactant leads to a different type of complex when isolated as a crystalline material. A spectroscopic study of the interaction of complex, 2 with calf thymus-DNA (CT-DNA) in Tris-HCl buffer showed a significant non-intercalative interaction with a binding constant (Kb) of 4.7 × 104 M−1, and the linear Stern-Volmer quenching constant (Ksv) and the binding sites (n) were found to be 1.3 × 103 and 0.92 respectively, calculated from ethidium bromide (EB) fluorescence displacement experiments. 相似文献
962.
V. Pralong V. Caignaert T. Sarkar O.I. Lebedev V. Duffort B. Raveau 《Journal of solid state chemistry》2011,184(9):2588-2594
The study of the oxidation of the “114” orthorhombic cobaltite CaBaCo4O7, using first electrochemistry and then soft chemistry based on oxidation by NaClO, has allowed a new phase, CaBaCo4O7.50, to be prepared topotactically. The structural study of this phase shows that its hexagonal structure, closely related to that of orthorhombic CaBaCo4O7, is curiously similar to that of the members of the LnBaCo4O7 series, in spite of its excess oxygen. Its magnetic study shows that this phase, like CaBaCo4O7, is ferrimagnetic with the same TC (60 K), but differently exhibits an unusual magnetic hysteresis. This exceptional behavior of CaBaCo4O7 with respect to oxidation as well as the magnetic properties of CaBaCo4O7.50 is interpreted in terms of the presence of defects due to oxidation. 相似文献
963.
A cysteamine (CysAm) nanostructure was generated to act as an intermediate layer between gold electrode and carbon nanotubes. A bare gold electrode was placed in a solution of CysAm to create a self-assembled monolayer on its surface. The modified electrode was then incubated with a solution of multi-walled carbon nanotubes. Cyclic voltammetry and atomic force microscopy were used to characterize the modified electrode. The results indicated that the number of functionalized MWCNTs on the surface of the electrodes increased by enhancing incubation time. Figure
The aim of this paper is to investigate the variations of incubation time of bare gold electrode inside cysteamine solution for immobilization of MWCNTs on cysteamine modified electrode. It is found that the number of functionalized MWCNTs on the surface of cysteamine modified electrode increased by enhancing incubation time bare gold electrode inside cysteamine solution. 相似文献
964.
Palash Sarkar 《Designs, Codes and Cryptography》2011,58(3):271-278
Let
\mathbbF{\mathbb{F}} be a finite field and suppose that a single element of
\mathbbF{\mathbb{F}} is used as an authenticator (or tag). Further, suppose that any message consists of at most L elements of
\mathbbF{\mathbb{F}}. For this setting, usual polynomial based universal hashing achieves a collision bound of
(L-1)/|\mathbbF|{(L-1)/|\mathbb{F}|} using a single element of
\mathbbF{\mathbb{F}} as the key. The well-known multi-linear hashing achieves a collision bound of
1/|\mathbbF|{1/|\mathbb{F}|} using L elements of
\mathbbF{\mathbb{F}} as the key. In this work, we present a new universal hash function which achieves a collision bound of
mélogm Lù/|\mathbbF|, m 3 2{m\lceil\log_m L\rceil/|\mathbb{F}|, m\geq 2}, using 1+élogm Lù{1+\lceil\log_m L\rceil} elements of
\mathbbF{\mathbb{F}} as the key. This provides a new trade-off between key size and collision probability for universal hash functions. 相似文献
965.
For the first time we propose the phenomenon of coupled tapering and uptapering in two mutually incoherent beams coaxially co-propagating in a nonlinear medium with small gain or loss. During tapering or uptapering, the widths and powers of the beams evolve in such a manner that they always satisfy the condition of soliton pairing. It is shown that under certain condition one beam can taper/uptaper, while, other uptaper/taper during coupled tapering/uptapering which is quite counterintuitive. 相似文献
966.
Violation of Lorentz invariance (VLI) has been suggested as an explanation of the superluminal velocities of muon neutrinos reported by OPERA. In this Letter, we show that the amount of VLI required to explain this result poses severe difficulties with the kinematics of the pion decay, extending its lifetime and reducing the momentum carried away by the neutrinos. We show that the OPERA experiment limits α=(ν(ν)-c)/c<4×10(-6). We then take recourse to cosmic-ray data on the spectrum of muons and neutrinos generated in Earth's atmosphere to provide a stronger bound on VLI: (ν-c)/c<10(-12). 相似文献
967.
Adriani O Barbarino GC Bazilevskaya GA Bellotti R Boezio M Bogomolov EA Bongi M Bonvicini V Borisov S Bottai S Bruno A Cafagna F Campana D Carbone R Carlson P Casolino M Castellini G Consiglio L De Pascale MP De Santis C De Simone N Di Felice V Galper AM Gillard W Grishantseva L Jerse G Karelin AV Koldashov SV Krutkov SY Kvashnin AN Leonov A Malakhov V Malvezzi V Marcelli L Mayorov AG Menn W Mikhailov VV Mocchiutti E Monaco A Mori N Nikonov N Osteria G Palma F Papini P Pearce M Picozza P 《Physical review letters》2011,106(20):201101
Precision measurements of the electron component in the cosmic radiation provide important information about the origin and propagation of cosmic rays in the Galaxy. Here we present new results regarding negatively charged electrons between 1 and 625 GeV performed by the satellite-borne experiment PAMELA. This is the first time that cosmic-ray e? have been identified above 50 GeV. The electron spectrum can be described with a single power-law energy dependence with spectral index -3.18 ± 0.05 above the energy region influenced by the solar wind (> 30 GeV). No significant spectral features are observed and the data can be interpreted in terms of conventional diffusive propagation models. However, the data are also consistent with models including new cosmic-ray sources that could explain the rise in the positron fraction. 相似文献
968.
We used an approach based on the self-imaging property of gratings to fabricate high-resolution Fresnel zone plates (FZPs). Under certain conditions, the illumination of a parent ZP with a wideband EUV beam produces a radially oscillating intensity distribution with double the spatial frequency of the ZP. This intensity distribution is observed in a certain distance range, given by the local zone width, the focal length of the ZP, and the spectral bandwidth of the illuminating beam. This phenomenon has been used to lithographically record daughter ZPs that have approximately half the zone width, thus twice the resolution, of the parent ZP. FZPs with zone widths as low as 30 nm have been fabricated in this way. Use of this technique in the extreme ultraviolet (EUV) region has the potential for high throughput production of FZPs and similar high-resolution diffraction optics with variable spatial frequency for the EUV and x-ray regions. 相似文献
969.
Amir Reza Hanifi Alireza TorabiThomas H. Etsell Luis YamartePartha Sarkar 《Solid State Ionics》2011,192(1):368-371
Due to the poor redox cycling resistance of the second generation of μ-SOFCs, a new generation of SOFC has been recently developed using a porous electrolyte-supported structure to overcome this problem. In this research, the porous structure was successfully fabricated with slip casting using calcined YSZ (ZrO2 + 8 mol% Y2O3) with or without graphite as a pore former. Calcination of YSZ powder at 1300-1500 °C prior to making the slip leads to growth of YSZ crystals and particle size which results in a decrease in surface area and powder sinterability. This was found to be an important criterion in developing the porous structure as, due to the high sinterability of non-calcined YSZ, even the addition of graphite is inadequate to generate sufficient open porosity. A dense YSZ electrolyte layer was immediately coated on the porous structure using YSZ calcined at 1300 °C with a sequential slip casting method. Sample thickness was found to be a function of both graphite content as well as YSZ calcination temperature. Physical properties of the porous YSZ supports and SEM analysis of the support and coated electrolyte are presented. 相似文献
970.
This study investigates the dip coating fabrication process in detail. First the slurry formulation development is presented. This includes optimizing the concentration of slurry components. Controlling the coating thickness is then addressed. It is shown that a broad range of uniform thicknesses from a few microns up to a few hundreds of microns is achievable by adjusting the solid loading and/or the dip coating rate. This study reports that dip coating is a commercially reliable technique to fabricate micro-tubular solid oxide fuel cells not only because it is low cost but, more importantly, because it is fairly reproducible and highly controllable. 相似文献