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101.
Under the assumption that solutions have traveling-wave form, time-periodic solutions are found for the Josephson phase equation for a finite-length tunnel junction with uniform current feed and linear loss term. Exact current-voltage characteristics are found and compared with simple approximations. The complete current-velocity and mean-width-velocity curves for isolated fluxons are found. Comparison with characteristics for a finite junction shows that end effects obtained from analysis of a circuit model of the junction shows that end effects introduce lower- and upper-current thresholds. 相似文献
102.
The optical reflectivity of the red bronze K0.33MoO3 has been measured on single crystals in the spectral energy range between 0.03 and 12 eV at temperatures from 4 K to 300 K using polarized light. The optical constants have been determined by means of a Kramers-Kronig analysis; the data are interpreted that this compound is a 0.5 eV energy gap semiconductor with very strong anisotropy in the infrared and visible energy range. 相似文献
103.
Neil Marcus 《General Relativity and Gravitation》1990,22(8):873-881
An exact solution of Einstein gravity coupled to a dilaton field is found. The solution is conformally flat and is invariant under Lorentz transformations. The singularities and conformal structure of the metric are examined. 相似文献
104.
Mayron César O. Moreira Marcus Ritt Alysson M. Costa Antonio A. Chaves 《Journal of Heuristics》2012,18(3):505-524
We propose simple heuristics for the assembly line worker assignment and balancing problem. This problem typically occurs
in assembly lines in sheltered work centers for the disabled. Different from the well-known simple assembly line balancing
problem, the task execution times vary according to the assigned worker. We develop a constructive heuristic framework based
on task and worker priority rules defining the order in which the tasks and workers should be assigned to the workstations.
We present a number of such rules and compare their performance across three possible uses: as a stand-alone method, as an
initial solution generator for meta-heuristics, and as a decoder for a hybrid genetic algorithm. Our results show that the
heuristics are fast, they obtain good results as a stand-alone method and are efficient when used as a initial solution generator
or as a solution decoder within more elaborate approaches. 相似文献
105.
Emmanuel Fernández-Gaucherand Mrinal K. Ghosh Steven I. Marcus 《Mathematical Methods of Operations Research》1994,39(2):131-155
Stochastic control problems for controlled Markov processes models with an infinite planning horizon are considered, under some non-standard cost criteria. The classical discounted and average cost criteria can be viewed as complementary, in the sense that the former captures the short-time and the latter the long-time performance of the system. Thus, we study a cost criterion obtained as weighted combinations of these criteria, extending to a general state and control space framework several recent results by Feinberg and Shwartz, and by Krass et al. In addition, a functional characterization is given for overtaking optimal policies, for problems with countable state spaces and compact control spaces; our approach is based on qualitative properties of the optimality equation for problems with an average cost criterion.Research partially supported by the Engineering Foundation under grant RI-A-93-10, in part by the National Science Foundation under grant NSF-INT 9201430, and in part by a grant from the AT&T Foundation.Research partially supported by the Air Force Office of Scientific Research under Grant F49620-92-J-0045, and in part by the National Science Foundation under Grant CDR-8803012. 相似文献
106.
The complete 13C NMR resonances for the sesquiterpene lactone 11,13-dihydroparthenolide were established by the application of 2D-INADEQUATE. 相似文献
107.
Christian Brackmann Odd Hole Bo Zhou Zhongshan S. Li Marcus Aldén 《Applied physics. B, Lasers and optics》2014,115(1):25-33
Two-photon laser-induced fluorescence (LIF) of ammonia (NH3) with excitation of the C′-X transition at 304.8 nm and fluorescence detection in the 565 nm C′-A band has been investigated, targeting combustion diagnostics. The impact of laser irradiance, temperature, and pressure has been studied, and simulation of NH3-spectra, fitted to experimental data, facilitated interpretation of the results. The LIF-signal showed quadratic dependence on laser irradiance up to 2 GW/cm2. Stimulated emission, resulting in loss of excited molecules, is induced above 10 GW/cm2, i.e., above irradiances attainable for LIF imaging. Maximum LIF-signal was obtained for excitation at the 304.8 nm bandhead; however, lower temperature sensitivity over the range 400–700 K can be obtained probing lines around 304.9 nm. A decrease in fluorescence signal was observed with pressure up to 5 bar absolute and attributed to collisional quenching. A detection limit of 800 ppm, at signal-to-noise ratio 1.5, was identified for single-shot LIF imaging over an area of centimeter scale, whereas for single-point measurements, the technique shows potential for sub-ppm detection. Moreover, high-quality NH3-imaging has been achieved in laminar and turbulent premixed flames. Altogether, two-photon fluorescence provides a useful tool for imaging NH3-detection in combustion diagnostics. 相似文献
108.
Fredrik?AnderssonEmail author Marcus?Carlsson Viktor?V.?Nikitin 《Journal of Fourier Analysis and Applications》2018,24(2):431-450
The Fourier slice theorem for the standard Radon transform generalizes to a Laplace counterpart when considering the exponential Radon transform. We show how to use this fact in combination with algorithms for the unequally spaced fast Laplace transform to construct fast and accurate methods for computing both the forward exponential Radon transform and the corresponding back-projection operator. 相似文献
109.
Quantitative model of price diffusion and market friction based on trading as a mechanistic random process 总被引:1,自引:0,他引:1
We model trading and price formation in a market under the assumption that order arrival and cancellations are Poisson random processes. This model makes testable predictions for the most basic properties of markets, such as the diffusion rate of prices (which is the standard measure of financial risk) and the spread and price impact functions (which are the main determinants of transaction cost). Guided by dimensional analysis, simulation, and mean-field theory, we find scaling relations in terms of order flow rates. We show that even under completely random order flow the need to store supply and demand to facilitate trading induces anomalous diffusion and temporal structure in prices. 相似文献
110.
Marcus Carlsson 《Integral Equations and Operator Theory》2008,61(4):593-598
In [3], M. J. Cowen and R. G. Douglas prove that the adjoint of a Hilbert space operator T is in the class if and only if T is unitarily equivalent with the operator M
z
on a Hilbert space -valued analytic functions, where M
z
denotes the operator of multiplication by the independent variable. The proof involves holomorphic vector bundles and Grauert’s
theorem.
In this paper we use a theorem by I. Gohberg and L. Rodman [4] to give a more elementary proof of this fact, which also works
for Banach space operators.
相似文献