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191.
192.
This paper proposes a technique for online determination of the model parameters of synchronous generators, using pseudorandom binary sequence (PRBS) perturbations applied to the reference input of the automatic voltage regulator (AVR). First-order circuit models and the associated mathematical relationships are given for d-axis and q-axis representations of the generator, and the parameter estimation algorithm and implementation thereof are discussed. Experimental results are given for a 5 kVA round rotor synchronous generator. The estimated parameter values are compared with manufacturer's data and are also validated by comparing measured and simulated time-domain responses for the d-axis and q-axis currents and the field current. The technique yields good results, particularly for the magnetizing inductances, winding resistances and the field to stator transformation ratio. 相似文献
193.
Jan Friso Groote Wim H. Hesselink Sjouke Mauw Rogier Vermeulen 《Distributed Computing》2001,14(2):75-81
Summary. The problem of using P processes to write a given value to all positions of a shared array of size N is called the Write-All problem. We present and analyze an asynchronous algorithm with work complexity , where (assuming and ). Our algorithm is a generalization of the naive two-processor algorithm where the two processes each start at one side of
the array and walk towards each other until they collide.
Received: October 1999 / Accepted: September 2000 相似文献
194.
195.
A Martin-Villalba C Winter S Brecht T Buschmann M Zimmermann T Herdegen 《Canadian Metallurgical Quarterly》1998,62(2):158-166
To determine if intestinal stromal cells secrete diffusible factors such as insulin-like growth factors (IGFs) capable of regulating epithelial cell growth in vitro, stromal cells were isolated by enzymatic digestion of rat intestine. Incorporation of [3H]thymidine into DNA and [14C]leucine into protein of IEC-6 cells, a model intestinal epithelial cell line, was significantly increased (two- to threefold) when the IEC-6 cells were co-cultured with stromal cells, relative to IEC-6 cells grown alone. Medium conditioned by stromal cells stimulated DNA synthesis of IEC-6 cells in a dose-dependent manner. Analysis of the conditioned medium revealed that intestinal stromal cells secreted IGF-I, but little IGF-II, in addition to an M(r) 32,000 IGF-binding protein (IGFBP-2) and an IGFBP having M(r) approximately 24,000. We conclude that rat intestinal stromal cells secrete one or more diffusible factors, which may include IGF-I and IGFBPs, capable of stimulating proliferation of IEC-6 cells in vitro. 相似文献
196.
Implementation of wind energy in the Netherlands: the importance of the social–institutional setting
This paper analyses the differences in performance of the different types of wind power entrepreneurs now active on the wind power supply market in the Netherlands. The development of the market is divided into three successive market periods: Monopoly powers (1989–1995), Interbellum (1996–1997) and Free market (1998–2002). For each of these periods, the interdependency between various systemic conditions—technical, economic, institutional and social conditions—is analysed, with the focus on the relative importance of the institutional and social settings for market development. This interdependency is analysed using the implementation capacity concept. Implementation capacity is defined as the total of those systemic conditions and mutual interdependencies that influence the behaviour of wind power entrepreneurs. It indicates the feasibility for wind power entrepreneurs to adopt wind turbines. From the analysis it was concluded that no overall implementation capacity exists, and implementation capacities differ for entrepreneurial groups with different entrepreneurial features. With respect to the relative importance of institutional and social conditions, it became clear, that it is mainly these conditions that differentiate between the various entrepreneurial groups. The dynamic configuration of institutional and social conditions facilitates some and hinders other types of wind power entrepreneurs, and as a result determines the development and composition of the market. Finally, the analysis explains the changing roles of entrepreneurial groups throughout the 1990s. 相似文献
197.
We consider an effect of the demagnetizing field, produced by the magnetic moments of nuclei of3He, on coherent precession of spin in liquid spin polarized3He or in spin polarized solutions of3He in4He. Formulae for the shape of the precessing domain wall and for the relaxation rate of the coherently precessing structure
are rederived taking into account the demagnetizing field. For pure3He and concentrated solutions of3He in4He the width of the domain wall increases and the relaxation rare decreases with polarization. Measurement of the relaxation
rate of the precessing structure can be used as an alternative method for the determination of the spin diffusion coefficient
in Fermi liquids. 相似文献
198.
Marinissen E.J. Vermeulen B. Hollmann H. Bennetts R.G. 《Design & Test of Computers, IEEE》2003,20(2):8-18
When testing the interconnect structures on a board, test programmers sometimes ask, How can I control the test pattern generation process to avoid ground bounce problems during Extest mode? Those wishing to satisfy a simultaneously-switching-outputs constraint will find several new solutions in this article. 相似文献
199.
200.
JG Bessems MJ de Groot EJ Baede JM te Koppele NP Vermeulen 《Canadian Metallurgical Quarterly》1998,28(9):855-875
1. The formation of free radicals during enzyme catalysed oxidation of eight 3,5-disubstituted analogues of paracetamol (PAR) has been studied. A simple peroxidase system as well as cytochrome P450-containing systems were used. Radicals were detected by electron spin resonance (ESR) on incubation of PAR and 3,5-diCH3-, 3,5-diC2H5-, 3,5-ditC4H9-, 3,5-diOCH3-, 3,5-diSCH3-, 3,5-diF-, 3,5-diCl- and 3,5-diBr-substituted analogues of PAR with horseradish peroxidase in the presence of hydrogen peroxide (H2O2). Initial analysis of the observed ESR spectra revealed all radical species to be phenoxy radicals, based on the absence of dominant nitrogen hyperfine splittings. No radicals were detected in rat liver cytochrome P450-containing microsomal or reconstituted systems. 2. To rationalize the observed ESR spectra, hydrogen atom abstraction of PAR and four of the 3,5-disubstituted analogues (3,5-diCH3-, 3,5-diOCH3-, 3,5-diF- and 3,5-diCl-PAR) was calculated using ab initio calculations, and a singlet oxygen atom was used as the oxidizing species. The calculations indicated that for all compounds studied an initial hydrogen atom abstraction from the phenolic hydroxyl group is favoured by approximately 125 kJ/mol over an initial hydrogen atom abstraction from the acetylamino nitrogen atom, and that after hydrogen abstraction from the phenolic hydroxyl group, the unpaired electron remains predominantly localised at the phenoxy oxygen atom (+/-85%). 3. The experimental finding of phenoxy radicals in horseradish peroxidase/H2O2 incubations paralleled these theoretical findings. The failure to detect experimentally phenoxy radicals in cytochrome P450-catalysed oxidation of any of the eight 3,5-disubstituted PAR analogues is more likely due to the reducing effects that agents like NADPH and protein thiol groups have on phenoxy radicals rather than on the physical instability of the respective substrate radicals. 相似文献