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71.
72.
Das Arulsamy A Kregar Z Eleršič K Modic M Subramani US 《Physical chemistry chemical physics : PCCP》2011,13(33):15175-15181
Hydrogen produced from the photocatalytic splitting of water is one of the reliable alternatives to replace the polluting fossil and the radioactive nuclear fuels. Here, we provide unequivocal evidence for the existence of blue- and red-shifting O-H covalent bonds within a single water molecule adsorbed on the MgO surface as a result of asymmetric displacement polarizabilities. The adsorbed H-O-H on MgO gives rise to one weaker H-O bond, while the other O-H covalent bond from the same adsorbed water molecule compensates this effect with a stronger bond. The weaker bond (nearest to the surface), the interlayer tunneling electrons and the silver substrate are shown to be the causes for the smallest dissociative activation energy on the MgO monolayer. The origin that is responsible to initiate the splitting mechanism is proven to be due to the changes in the polarizability of an adsorbed water molecule, which are further supported by the temperature-dependent static dielectric constant measurements for water below the first-order electronic-phase transition temperature. 相似文献
73.
Andrew M. Edmonds Mushtaq A. Sobhan Varun K. A. Sreenivasan Ekaterina A. Grebenik James R. Rabeau Ewa M. Goldys Andrei V. Zvyagin 《Particle & Particle Systems Characterization》2013,30(6):506-513
Bioprobes based on fluorescent ruby nanoparticles, which are suitable for ultrasensitive imaging, are reported. A stable aqueous/buffer colloid, permitting facile conjugation to proteins, is produced by femtosecond laser ablation of ruby and the nanoparticles (mean size 17 nm) are photostable, with long lifetime (1–4 ms) 694 nm emission. With time‐gating complete (>20 dB) suppression of cell autofluorescence and suppression of exogenous fluorophores is observed. Nanoparticles are imaged in as‐grown cells and those immunolabeled with quantum dots. Immunoassay binding to target biomolecules is also demonstrated. 相似文献
74.
We report about the observation of microtubules lying underneath the cell membrane of neural process in neurons with a resolution as high as that of an electron microscope by an illumination mode photon scanning tunneling microscope. Nanoapertures used in our observations were fabricated by means of selective chemical etching and metal coating of an optical fiber. The narrowest observed tube has got an average diameter of 26 nm. Comparing this with its nominal value of 25 nm, the difference which is considered as a measure of resolution (δ) is 1 nm implying a resolution comparable to that of an electron microscope in imaging dielectric specimens. This was possible due to the presence of a boundary between the glass and the metal coating and also due to the use of an aperture of almost the same size as that of the microtubule that enhances the detection. 相似文献
75.
Kunj Behari Uma Agrawal Rima Das 《Journal of polymer science. Part A, Polymer chemistry》1993,31(6):1449-1452
Gel-free cyclopolymerization of N,N′-methylenebisacrylamide has been carried out using potassium peroxodiphosphate (PDP) as initiator in combination with different activators such as mercaptosuccinic acid (MSA) and thioglycollic acid (TGA) in an inert atmosphere at 45 ± 1°C and 40 ± 1°C, respectively. The rate of polymerization was found proportional to the first power of the monomer and activator concentration and the half-power of PDP in both redox systems. A mechanism involving cyclopolymerization in the propagation path has been proposed. © 1993 John Wiley & Sons, Inc. 相似文献
76.
Most of the works in Time Series Analysis are based on the Auto Regressive Integrated Moving Average (ARIMA) models presented by Box and Jenkins(1976). If the data exhibits no apparent deviation from stationarity and if it has rapidly decreasing autocorrelation function then a suitable ARMA(p,q) model is fit to the given data. Selection of the orders of p and q is one of the crucial steps in Time Series Analysis. Most of the methods to determine p and q are based on the autocorrelation function and partial autocorrelation function as suggested by Box and Jenkins (1976). Many new techniques have emerged in the literature and it is found that most of them are of very little use in determining the orders of p and q when both of them are non-zero. The Durbin-Levinson algorithm and Innovation algorithm (Brockwell and Davis, 1987) are used as recursive methods for computing best linear predictors in an ARMA(p,q) model. These algorithms are modified to yield an effective method for ARMA model identification so that the values of order p and q can be determined from them. The new method is developed and its validity and usefulness is illustrated by many theoretical examples. This method can also be applied to any real world data. 相似文献
77.
A tentative suggestion is made that the flatness of the velocity derivative could reach an infinite value at finite (though
very large) Reynolds number, with possible implications for the singularities of the Navier—Stokes equations. A direct test
of this suggestion requires measurements at Reynolds numbers presently outside the experimental capacity, so an alternative
suggestion that can be tested at accessible Reynolds numbers is also made. 相似文献
78.
We propose a new approximation scheme to obtain analytic expressions for the bond-state energies and eigenfunctions for any arbitrary bound nl-state of the Hulthén potential. The predicted energies Enl are in excellent agreement with the perturbative results of Lai and Lin. The scope for an extension of the method to the continuum states is also discussed. 相似文献
79.
The ruthenium(II) complex [RuI2(Me2SO)4] was synthesized and characterized. The Me2SO ligands are all S-bonded. Reactions of RuI2(Me2SO)4 with ligands containing P, N and S donor atoms have been carried out and the complexes obtained were characterized using different physical methods. [RuI2L4] (L= CH3CN, Me2SO and py), [RuI2(CH3CN)2(PPh3)2] and [RuI2(CS)(PPh3)3] have been synthesized using RuI3 as the source material and characterized as above. 相似文献
80.
Gregory A. Dilisi Charles Rosenblatt Robert B. Akins Anselm C. Griffin Uma Hari 《Liquid crystals》1992,11(1):63-71
The dialkoxyphenylbenzoate monomer '5005' (C5H11OC6H4COOC6H4OC5H11) and its dimer were aligned parallel to a buffed polyimide-coated glass substrate. A magnetically induced Freedericksz transition in both thick and thin cells was used in conjunction with a capacitance technique to determine the anchoring strength coefficient Was a function of temperature in the nematic phase. It was found that for both monomer and dimer, Wincreases with decreasing temperature. The anchoring coefficient for the dimer, however, was found to be an order of magnitude larger than for the monomer at comparable reduced temperatures. The splay elastic moduli were also determined for both species, and found to be of comparable magnitude, consistent with previous results. 相似文献