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141.
The effective Lagrangian of a point charge is derived by eliminating the electromagnetic field within the framework of the classical closed time path formalism. The short distance singularity of the electromagnetic field is regulated by an UV cutoff. The Abraham–Lorentz force is recovered and its similarity to quantum anomalies is underlined. The full cutoff-dependent linearized equation of motion is obtained, no runaway trajectories are found but the effective dynamics shows acausality if the cutoff is beyond the classical charge radius. The strength of the radiation reaction force displays a pole in its cutoff-dependence in a manner reminiscent of the Landau-pole of perturbative QED. Similarity between the dynamical breakdown of the time reversal invariance and dynamical symmetry breaking is pointed out. 相似文献
142.
Carano RA Lynch JA Redei J Ostrowitzki S Miaux Y Zaim S White DL Peterfy CG Genant HK 《Magnetic resonance imaging》2004,22(4):505-514
Quantitative measures of rheumatoid arthritis (RA) disease progression can provide valuable tools for evaluation of new treatments during clinical trials. In this study, a novel multispectral (MS) MRI analysis method is presented to quantify changes in bone lesion volume (DeltaBLV) in the hands of RA patients. Image registration and MS analysis were employed to identify MS tissue class transitions between two serial MRI exams. DeltaBLV was determined from MS class transitions between two time points. The following three classifiers were investigated: (a) multivariate Gaussian (MVG), (b) k-nearest neighbor (k-NN), and (c) K-means (KM). Unlike supervised classifiers (MVG, k-NN), KM, an unsupervised classifier, does not require labeled training data, resulting in potentially greater clinical utility. All MS estimates of DeltaBLV were linearly correlated (r(p)) with manual estimates. KM and k-NN estimates also exhibited a significant rank-order correlation (r(s)) with manual estimates. For KM, r(p) = 0.94 p < 0.0001, r(s) = 0.76 p = 0.002; for k-NN, r(p) = 0.86 p = 0.0001, r(s) = 0.69 p = 0.009; and for MVG, r(p) = 0.84 p = 0.0003, r(s) = 0.49 p = 0.09. Temporal classification rates were as follows: for KM, 90.1%; for MVG, 89.5%; and for k-NN, 86.7%. KM matched the performance of k-NN, offering strong potential for use in multicenter clinical trials. This study demonstrates that MS tissue class transitions provide a quantitative measure of DeltaBLV. 相似文献
143.
Raimundo F. Miambo Marie Laronze-Cochard Ata-Martin Lawson Régis Guillot Brigitte Baldeyrou Amélie Lansiaux Claudiu T. Supuran Janos Sapi 《Tetrahedron》2014
A number of isothiazolo[4,5-b]carbazole derivatives were prepared via a Diels–Alder approach involving thermally induced indole-2,3-quinodimethane intermediates. Preliminary biological tests revealed a GSK-3β kinase inhibitor (29) and some free NH group containing compounds (17d, 19c, 29) displayed selective human carbonic anhydrase I inhibitory activities. 相似文献
144.
145.
We show, using a specific example of a chemical reaction, that the rate constants predicted from the discrete master equation and its continuum Fokker-Planck approximations differ in exponential order with respect to the size of the system. 相似文献
146.
Stability of a two degrees of freedom model of the turning process is considered. An accurate modeling of the surface regeneration
shows that the regenerative delay, determined by the combination of the workpiece rotation and the tool vibrations, is in
fact state-dependent. For that reason, the mathematical model considered in this paper is a delay-differential equation with
state-dependent time delay. In order to study linearized stability of stationary cutting processes, an associated linear system,
corresponding to the state-dependent delay equation, is derived. Stability analysis of this linear system is performed analytically.
A comparison between the state-dependent delay model and the previously used constant or time-periodic delay models shows
that the incorporation of the state-dependent delay into the model slightly affects the linear stability properties of the
system in certain parameter domains. 相似文献
147.
Janos H. Fendler 《Journal of Dispersion Science and Technology》2013,34(1-2):13-25
Abstract The layer-by-layer self-assembly of poly(diallyldimethyl-ammonium) chloride, PDDA; graphite oxide, G, nanoplatelets; and polyethylene oxide, PEO, onto transparent indium tin oxide substrates, S, have provided cationic working electrodes which, with lithium wires as reference and counter electrodes, functioned as high energy density rechargeable lithium-ion batteries. Specifically, very high specific capacities (1232 and 1134 mAh.g?1) have been determined for batteries which had positive electrodes of ten sandwich layers of self-assembled films: S-(PDDA/GO/PEO)10 and S-(PDDA/PEO)10. The importance of the exfoliating GO into nanoplatelets and the colloid chemistry of self-assembly are discussed. 相似文献
148.
149.
Combining the arguments developed in the works of D. A. Goldston,S. W. Graham, J. Pintz, and C. Y. Yildirim [Preprint, 2005,arXiv: math.NT/506067] and Y. Motohashi [Number theory in progress– A. Schinzel Festschrift (de Gruyter, 1999) 1053–1064]we introduce a smoothing device to the sieve procedure of Goldston,Pintz, and Yildirim (see [Proc. Japan Acad. 82A (2006) 61–65]for its simplified version). Our assertions embodied in Lemmas3 and 4 of this article imply that a natural extension of aprime number theorem of E. Bombieri, J. B. Friedlander, andH. Iwaniec [Theorem 8 in Acta Math. 156 (1986) 203–251]should give rise infinitely often to bounded differences betweenprimes, that is, a weaker form of the twin prime conjecture. 相似文献
150.
Mario Goffredi Janos Liszi Bela Nemeth Vincenzo Turco Liveri 《Journal of solution chemistry》1983,12(4):221-231
Calorimetric determinations of the thermodynamics of transfer of nitromethane, nitroethane, 1-nitrobutane, 1-nitropentane, and 1-nitrohexane from n-octane to water at 25°C have been made. Transfer free energies calculated by four different models agree reasonably well with observations. Calculations indicate that the dipolar part of the transfer free energy depends only on the dipole moment and size of the-C?NO2 group and is independent of the length of the alkyl chain in nitroalkanes. 相似文献