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51.
An extended flavour symmetry for hadrons is presented in which the narrow hadronic widths of the ψ particles are attributed to approximate conservation of a new internal spin quantum number. Wider vector states are predicted at higher energies, and other experimental consequences (including the existence of a new charged lepton) are suggested. 相似文献
52.
53.
Atomic force microscopy operating in the contact mode is studied using total-energy pseudopotential calculations. It is shown that, in the case of a diamond tip and a diamond surface, it is possible for a tip terminated by a single atom to sustain forces in excess of 30 nN. It is also shown that imaging at atomic resolution may be limited by blunting of the tip during lateral scanning. 相似文献
54.
S Takeda R Ptak C Nakamura J Miyake M Kageshima S P Jarvis H Tokumoto 《Chemical & pharmaceutical bulletin》2001,49(12):1512-1516
Using atomic force microscopy (AFM), the length of the alpha-helix structure of poly-L-lysine was investigated by stretching the peptide directly, one molecule at a time. In the absence of urea, many rupturing points that seemed to be due to the breaking of some hydrogen bonds were observed in force-extension curves, while these points were never observed in the presence of 8 M urea. In the presence of 0.4 or 1.6 M urea, both force-extension curve types were observed. Total peptide elongation for each condition was calculated from force-extension curves reflecting the alpha-helix rupturing process. The experimental value of total elongation divided by the theoretical value of total alpha-helix elongation yields the alpha-helix content. This value was compatible with circular dichroism (CD) measurement results. This suggests that peptide conformation and content of the alpha-helix on a single molecule scale can be investigated by direct mechanical measurement using atomic force microscopy. 相似文献
55.
We prove the genus zero part of the generalized Witten conjecture, relating moduli spaces of higher spin curves to Gelfand–Dickey hierarchies. That is, we show that intersection numbers on the moduli space of stable r-spin curves assemble into a generating function which yields a solution of the semiclassical limit of the KdV
r
equations. We formulate axioms for a cohomology class on this moduli space which allow one to construct a cohomological field theory of rank r–1 in all genera. In genus zero it produces a Frobenius manifold which is isomorphic to the Frobenius manifold structure on the base of the versal deformation of the singularity A
r–1. We prove analogs of the puncture, dilaton, and topological recursion relations by drawing an analogy with the construction of Gromov–Witten invariants and quantum cohomology. 相似文献
56.
This paper presents a discrete time receding horizon control scheme that leverages the numerical properties of a variational integrator to facilitate real-time control generation on an embedded system. The variational integrator employed is well-suited to classical estimation and control algorithms, e.g. LQR, extended Kalman filters, and particle filters. The structure-preserving properties of this variational integrator lead to increased performance of estimation and control routines, especially in low-bandwidth applications. Several experimental examples are presented that illustrate the features of this receding horizon control scheme when leveraging the desirable numerical properties of the variational integrator. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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58.
Shawn R. Hitchcock Ryan A. Davis Daniel M. Richmond Delvis D. Dore Stephanie L. Kuschel Jeremy F. Vaughn Jesse A. Wolfe Christopher G. Hamaker David M. Casper Jarvis Dingle 《Journal of heterocyclic chemistry》2008,45(5):1265-1274
59.
60.
Winder CL Cornmell R Schuler S Jarvis RM Stephens GM Goodacre R 《Analytical and bioanalytical chemistry》2011,399(1):387-401
Fourier transform infrared (FT-IR) spectroscopy was employed as a rapid high-throughput phenotypic typing technique to generate
metabolic fingerprints of Escherichia coli MG1655 pDTG601A growing in fed-batch culture, during the dioxygenase-catalysed biotransformation of toluene to toluene cis-glycol. With toluene fed as a vapour, the final toluene cis-glycol concentration was 83 mM, whereas the product concentration was only 22 mM when the culture was supplied with liquid
toluene. Multivariate statistical analysis employing cluster analysis was used to analyse the dynamic changes in the data.
The analysis revealed distinct trends and trajectories in cluster ordination space, illustrating phenotypic changes related
to differences in the growth and product formation of the cultures. In addition, partial least squares regression was used
to correlate the FT-IR metabolic fingerprints with the levels of toluene cis-glycol and acetate, the latter being an indicator of metabolic stress. We propose that this high-throughput metabolic fingerprinting
approach is an ideal tool to assess temporal biochemical dynamics in complex biological processes, as demonstrated by this
redox biotransformation. Moreover, this approach can also give useful information on product yields and fermentation health
indicators directly from the fermentation broth without the need for lengthy chromatographic analysis of the products. 相似文献