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991.
Modeling mechatronic multibody systems requires the same type of methodology as for designing and prototyping mechatronic
devices: a unified and integrated engineering approach. Various formulations are currently proposed to deal with multiphysics
modeling, e.g., graph theories, equational approaches, co-simulation techniques. Recent works have pointed out their relative
advantages and drawbacks, depending on the application to deal with: model size, model complexity, degree of coupling, frequency
range, etc. This paper is the result of a close collaboration between three laboratories, and aims at showing that for “non-academic”
mechatronic applications (i.e., issuing from real industrial issues), multibody dynamics formulations can be generalized to
mechatronic systems, for the model generation as well as for the numerical analysis phases. Model portability being also an
important aspect of the work, they must be easily interfaced with control design and optimization programs. A global “demonstrator”,
based on an industrial case, is discussed: multiphysics modeling and mathematical optimization are carried out to illustrate
the consistency and the efficiency of the proposed approaches. 相似文献
992.
993.
A recently proposed argument to explain the improved performance of the eight-point algorithm that results from using normalized
data (Chojnacki, W., et al. in IEEE Trans. Pattern Anal. Mach. Intell. 25(9):1172–1177, 2003) relies upon adoption of a certain model for statistical data distribution. Under this model, the cost function that underlies
the algorithm operating on the normalized data is statistically more advantageous than the cost function that underpins the
algorithm using unnormalized data. Here we extend this explanation by introducing a more refined, structured model for data
distribution. Under the extended model, the normalized eight-point algorithm turns out to be approximately consistent in a
statistical sense. The proposed extension provides a link between the existing statistical rationalization of the normalized
eight-point algorithm and the approach of Mühlich and Mester for enhancing total least squares estimation methods via equilibration.
The paper forms part of a wider effort to rationalize and interrelate foundational methods in vision parameter estimation. 相似文献
994.
995.
996.
E. M. Gavrishchuk E. Yu. Vilkova O. V. Timofeev U. P. Borovskikh E. L. Tikhonova 《Inorganic Materials》2007,43(6):579-583
Chemical interaction between polished surfaces of polycrystalline zinc selenide and inorganic acid solutions of various concentrations has been studied. 相似文献
997.
V. V. Ustinov A. B. Rinkevich L. N. Romashev E. A. Kuznetsov 《Technical Physics Letters》2007,33(9):771-774
The reflection of electromagnetic waves in the millimeter wave band from Fe/Cr nanostructures has been studied. It is established that the giant magnetoresistance (GMR) in the nanostructure leads to an increase in the reflection and a decrease in the transmission of microwaves, while the magnetic resonance leads to a decrease in both the reflection and transmission coefficients. 相似文献
998.
In the power industry, current has to be measured for metering and protection purposes. Conventional sensor setups need two transformers to realize the high dynamic range. By the described mixed analog/digital signal processing algorithm, the inherent low photonic noise of the input signals was maintained up to the full sensor output. The system design is based on a rigorous investigation and optimization of the error sources in the signal processing chain. The results are proved by a demonstrator, achieving a dynamic range from 0.05 to 100 times the rated current and a ratio root mean square error of less than 0.5%. 相似文献
999.
I. V. Oryshich N. E. Poryadchenko N. P. Brodnikovskii 《Powder Metallurgy and Metal Ceramics》2004,43(9-10):497-503
We have studied the oxidation resistance of chromium intermetallics: TiCr2, HfCr2, and ZrCr2, in the temperature interval 873–1473 K with isothermal holding of the specimens for up to 20 h. We have shown that the intermetallics TiCr2 and HfCr2 are oxidized 2–3 times more slowly than pure titanium and hafnium, but more than 1–2 orders of magnitude faster than chromium at T≤1273 K and 4–6 times faster at 1473 K. In this temperature interval, the intermetallic ZrCr2 is rapidly oxidized at an increasing rate as the heating temperature rises. The scaling resistance of intermetallics of Group IV d metals with chromium is determined by formation of scales in which the major role is played by the oxides TiO2, HfO2, and ZrO2, with weak protective properties. 相似文献
1000.
The shape of the impactor with the maximum depth of penetration (DOP) for a given impact velocity is found using a numerical procedure for solving a corresponding non-classical variational problem. It is shown that the optimum shape in a general case is close to a blunt cone. The variation of the optimal shape of the impactor and the dependence of the DOP vs. the initial (impact) velocity and friction coefficient is studied. The analysis is performed also for optimal conical impactors. 相似文献