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排序方式: 共有65条查询结果,搜索用时 31 毫秒
11.
Sreenu K. Sudhakar Reddy CH. Reddy J. R. Velchuri Radha Palla Suresh Vithal M. 《Research on Chemical Intermediates》2016,42(6):5765-5777
Research on Chemical Intermediates - Substitutional doping of framework heteroatoms in photocatalysis is one of the approaches for harvesting visible light. Tunnel structure potassium antimony... 相似文献
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A detailed analysis of the proton high-field NMR spectra of vinegars (in particular of Italian balsamic vinegars) is reported. A large number of organic substances belonging to different classes, such as carbohydrates, alcohols, organic acids, volatile compounds and amino acids, were assigned. The possibility of quantification of the substances identified in the whole vinegar sample, without extraction or pre-concentration steps, was also tested. The data validity was demonstrated in terms of precision, accuracy, repeatability and inter-day reproducibility. The effects of the most critical experimental parameters (sample concentration, water suppression and relaxation time) on the analysis response were also discussed. 1H NMR results were compared with those obtained by traditional techniques (GC-MS, titrations), and good correlations were obtained. The results showed that 1H NMR with water suppression allows a rapid, simultaneous determination of carbohydrates (glucose and fructose), organic acids (acetic, formic, lactic, malic, citric, succinic and tartaric acids), alcohols and polyols (ethanol, acetoin, 2,3-butanediol, hydroxymethylfurfural), and volatile substances (ethyl acetate) in vinegar samples. On the contrary, the amino acid determination without sample pre-concentration was critical. The 1H NMR method proposed was applied to different samples of vinegars, allowing, in particular, the discrimination of vinegars and balsamic vinegars. 相似文献
14.
Benavides GF Zimmerman JW Woodard BS Day MT King DM Carroll DL Palla AD Verdeyen JT Solomon WC 《Optics letters》2012,37(9):1409-1411
The authors report the development of an electric oxygen-iodine laser with higher output using a larger product of gain and gain length, g0L. A factor of 4.4 increase in laser power output on the 1315 nm atomic iodine transition was achieved with a factor of 3 increase in gain length. I(2P1/2) is pumped using energy transferred from O2(a1Δ) produced by flowing a gas mixture of O2-He-NO through three coaxial geometry radio-frequency discharges. Continuous wave (CW) average total laser power of 481 W was extracted with g0L=0.042. 相似文献
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Manca F Giordano S Palla PL Zucca R Cleri F Colombo L 《The Journal of chemical physics》2012,136(15):154906
Stretching experiments on single molecules of arbitrary length opened the way for studying the statistical mechanics of small systems. In many cases in which the thermodynamic limit is not satisfied, different macroscopic boundary conditions, corresponding to different statistical mechanics ensembles, yield different force-displacement curves. We formulate analytical expressions and develop Monte Carlo simulations to quantitatively evaluate the difference between the Helmholtz and the Gibbs ensembles for a wide range of polymer models of biological relevance. We consider generalizations of the freely jointed chain and of the worm-like chain models with extensible bonds. In all cases we show that the convergence to the thermodynamic limit upon increasing contour length is described by a suitable power law and a specific scaling exponent, characteristic of each model. 相似文献
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Santosh Kumar
Bhal Palla Danumjaya Graeme Fairweather 《Numerical Methods for Partial Differential Equations》2020,36(6):1811-1829
Orthogonal spline collocation is implemented for the numerical solution of two-dimensional Helmholtz problems with discontinuous coefficients in the unit square. A matrix decomposition algorithm is used to solve the collocation matrix system at a cost of O(N2 log N) on an N × N partition of the unit square. The results of numerical experiments demonstrate the efficacy of this approach, exhibiting optimal global estimates in various norms and superconvergence phenomena for a broad spectrum of wave numbers. 相似文献
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Paola Caroti Carlo Ceccotti Antonio Da Settimo Fabio Palla Giampaolo Primofiore 《Journal of heterocyclic chemistry》1986,23(6):1833-1836
Reaction between 2-chloropyridine-3-carbonyl chloride and 1-alkyl-2-aminobenzimidazoles afforded the N-(1-alkylbenzimidazole-2-yl)-2-chloropyridine-3-carboxamides, which were cyclized to 5,7-dihydro-5-oxopyrido[3′,2′:5,6]pyrimido[1,2-a]benzimidazoles. The assigned structures of these hitherto unknown heterocyclic compounds were confirmed by their ir and 1H nmr spectra and chemical evidence. 相似文献
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The mass spectrum of spontaneously compactified Einstein-Yang-Mills theories is computed using the Wu-Yang monopole harmonic functions. It is found that spontaneous compactification can be used to provide the correct mass scale generating the superstrong symmetry breaking which, in grand unified theories, separates quarks from leptons. 相似文献
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Gergely Palla Gábor Vattay André Voros Niels Søndergaard Carl Philip Dettmann 《Foundations of Physics》2001,31(4):641-657
We review studies of an evolution operator for a discrete Langevin equation with a strongly hyperbolic classical dynamics and a Gaussian noise. The leading eigenvalue of yields a physically measurable property of the dynamical system, the escape rate from the repeller. The spectrum of the evolution operator in the weak noise limit can be computed in several ways. A method using a local matrix representation of the operator allows to push the corrections to the escape rate up to order eight in the noise expansion parameter. These corrections then appear to form a divergent series. Actually, via a cumulant expansion, they relate to analogous divergent series for other quantities, the traces of the evolution operators n. Using an integral representation of the evolution operator , we then investigate the high order corrections to the latter traces. Their asymptotic behavior is found to be controlled by sub-dominant saddle points previously neglected in the perturbative expansion, and to be ultimately described by a kind of trace formula. 相似文献