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991.
Three new alkaline earth metal based MOFs have been synthesized by using 4,4'-sulfobisbenzoic acid (SBBA) and alkaline earth metal salts M(NO(3))(2), M = Ca, Sr, Ba. These MOFs exhibit interesting structural diversity, variable chemical stability as well as proton conductivity. 相似文献
992.
A Cu(II)-phenanthroline connected Strandberg-type polyoxometalate based proton conducting MOF, Cu(3)Mo(5)P(2), that contains one dimensional parallel water channels has been reported. Cu(3)Mo(5)P(2) shows proton conduction at room temperature as well as elevated temperature. 相似文献
993.
Pachfule P Balan BK Kurungot S Banerjee R 《Chemical communications (Cambridge, England)》2012,48(14):2009-2011
The loading of a Zn-terephthalate based MOF in the inner cavity as well as on the outer walls of a hollow carbon nanofiber (CNF) creates MOF@CNF hybrids. This hybrid 'MOF@CNF' displayed improved thermal stability as well as gas adsorption compared to the individual counterparts. 相似文献
994.
Banerjee S Ertel K Mason PD Phillips PJ Siebold M Loeser M Hernandez-Gomez C Collier JL 《Optics letters》2012,37(12):2175-2177
We report on the first demonstration of a diode-pumped, gas cooled, cryogenic multislab Yb:YAG amplifier. The performance was characterized over a temperature range from 88 to 175 K. A maximum small-signal single-pass longitudinal gain of 11.0 was measured at 88 K. When amplifying nanosecond pulses, recorded output energies were 10.1 J at 1 Hz in a four-pass extraction geometry and 6.4 J at 10 Hz in a three-pass setup, corresponding to optical to optical conversion efficiencies of 21% and 16%, respectively. To our knowledge, this represents the highest pulse energy so far obtained from a cryo-cooled Yb-laser and the highest efficiency from a multijoule diode pumped solid-state laser system. 相似文献
995.
In this paper it has been shown that the neutrino bulk viscous stresses can give rise to the late time acceleration of the universe. It is found that a number of spatially flat FRW models with a negative deceleration parameter can be constructed using neutrino viscosity and one of them mimics a ΛCDM model. This does not require any exotic dark energy component or any modification of gravity. 相似文献
996.
The self-assembly of non-toxic well-consumed small caffeine molecules into well-defined structures has important implications
for future medical applications seeking to target the transport of small drugs in human body. Particularly, the solvation
of the microenvironments of the self assembly ultimately dictates the interaction with the drug molecules and their therapeutic
efficacy. We present femtosecond-resolved studies of the dynamics of aqueous solvation within self-assembled dimeric structure
of caffeine molecules. We have placed small hydrophobic probes 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl) 4H-pyran
(DCM), coumarin 500 (C500) into the caffeine dimer to enable spectroscopic examinations of the interior. While molecular modeling
and NMR studies of the probes in the caffeine dimers reveal a well-defined location (stacked in between two caffeine molecules),
dynamical light scattering (DLS), Fourier transform infrared (FTIR) spectroscopy, densimetric and sonometric experiments explore
the structural evolution of the dimer upon complexation with the probes. We have extended our studies in various temperatures
in order to explore structural evolution of the self assembled structure and consequently the dynamics of solvation in the
interior of the dimer. Picoseconds/femtosecond resolved dynamics and the polarization gated spectroscopic studies unravel
the hydration and energetics associated with activated viscous flow of the confined probes. Our studies indicate that the
interior of the caffeine dimer is well-solvated; however, the dynamics of solvation is retarted significantly compared to
that in bulk water, clearly revealing the dimers maintain some ordered water molecules. We have also explored the consequence
of the retarded dynamics of solvation on the photo-induced electron transfer (ET) reaction of a model probe, 2-(p-toluidino)
naphthalene-6-sulfonate (TNS) encapsulated in the dimer. 相似文献
997.
Positive feedback and cooperativity in the regulation of gene expression are generally considered to be necessary for obtaining
bistable expression states. Recently, a novel mechanism of bistability termed emergent bistability has been proposed which
involves only positive feedback and no cooperativity in the regulation. An additional positive feedback loop is effectively
generated due to the inhibition of cellular growth by the synthesized proteins. The mechanism, demonstrated for a synthetic
circuit, may be prevalent in natural systems also as some recent experimental results appear to suggest. In this paper, we
study the effects of additive and multiplicative noise on the dynamics governing emergent bistability. The calculational scheme
employed is based on the Langevin and Fokker-Planck formalisms. The steady state probability distributions of protein levels
and the mean first passage times are computed for different noise strengths and system parameters. In the region of bistability,
the bimodal probability distribution is shown to be a linear combination of a lognormal and a Gaussian distribution. The variances
of the individual distributions and the relative weights of the distributions are further calculated for varying noise strengths
and system parameters. The experimental relevance of the model results is also pointed out. 相似文献
998.
Ritu Mishra Rupendranath Banerjee Subrata Mukhopadhyay 《Journal of Physical Organic Chemistry》2012,25(12):1193-1197
Copper(II) dramatically catalyzes the oxidation of thiols by a superoxide bridging two CoIII ions. The catalyzed path overwhelmingly dominates over the uncatalysed path and is first order in the superoxo complex concentration. The first‐order rate constants show a first‐order dependence in [Cu2+], a second‐order dependence in [thiol] and linearly varies with [H+]?3. On the basis of observed kinetics reported here, it is proposed that Cu(II) reacts with two thiol molecules to form a CuII(thiol)2 complex, an electron is transferred from one ligated thiol to the CuII center to form CuI(thiol) and a thiyl radical. The copper(I)‐thiol complex is oxidized by the conjugate base of the title complex to regenerate CuII(thiol). A CuII/I catalytic cycle is thus believed to be responsible for the observed catalysis. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
999.
R. K. Varma S. B. Banerjee A. Ambastha 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2012,66(2):38
Experimental results are presented here reporting the detection of a curl-free vector potential on the macro-scale as contrasted
with the detection on the micro-scale à la Aharonov-Bohm. Such a detection is attributed to the ‘quantum modulation’ of the
plane wave state of the guiding centre motion of a charged particle in a magnetic field, which is generated concomitantly
with the excitation of its Landau levels in a scattering episode, through the mechanism of quantum entanglement between the
parallel and perpendicular degrees of freedom of the particle. Such a ‘quantum modulation’ is also a matter wave, but on the
macro-scale, and leads to the ‘sensing’ of the curl-free vector potential on the macro-scale. Thus while the Aharonov-Bohm
effect is attributed to the sensing of the curl-free vector potential by the de Broglie wave, its sensing on the macro-scale
is attributed to the modulation of the de Broglie wave. 相似文献
1000.