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131.
The problem of primary and secondary frequency regulation of a multi-machine power system is analysed with a Liapunov function method based on a quadratic performance index. The main purpose is to determine the best set of parameters of primary and secondary regulation according to an optimisation criterion. The objective consists of achieving a settling time as short as possible which is relevant in a longitudinal system, whose structure includes long transmission lines with a reduced number of loops. 相似文献
132.
J López-Jiménez J Pérez-Oteyza A Munoz C Parra L Villalón P Ramos M Maldonado J García-Lara?a E Otheo E Roldán A García-Avello J Odriozola 《Canadian Metallurgical Quarterly》1997,19(5):429-434
Medorinone 5-methyl-1,6-napthyridin-2(1H)-one and some of its analogs having varying degrees of cardiotonic potency have been studied by molecular orbital and electric field mapping methods. Ground state geometries of the molecules were optimized using the MNDO molecular orbital method. Hybridization displacement charges (HDC) combined with L?wdin charges as well as Mulliken charges were used for electric field mapping around the molecules. Electric fields near the O2 site of medorinone and its analogs correlate well with their observed cardiotonic potencies. This result is in agreement with certain pharmacological models for cardiotonics. 相似文献
133.
Fuster J.M. Marti J. Corral J.L. Polo V. Ramos F. 《Lightwave Technology, Journal of》2000,18(7):933-940
The authors present a comprehensive analysis of the chromatic dispersion effects in harmonic upconverted millimeter-wave (mm-wave) fiber-optic links. The optical upconversion is performed through a photonic mixer based on a Mach-Zehnder electrooptical modulator. It is shown that by biasing the electrooptical modulator either at the maximum or at the minimum transmission bias points, the dispersion-induced power penalty effect on the upconverted signal may be sharply mitigated, which results in increasing the frequency-length product of the fiber-optic link. Experimental results are provided for the three different types of bias 相似文献
134.
J. A. Delgado Atencio E. E. Orozco Guillén S. Vázquez y Montiel M. Cunill Rodríguez J. Castro Ramos J. L. Gutiérrez F. Martínez 《Optical Memory & Neural Networks》2009,18(1):6-14
In a routine procedure for collecting human skin spectra using fiber optic diffuse reflectance spectroscopy, the fiber optic
probe is put gently in contact with the skin surface. The purpose of this work is to investigate the influence of probe pressure
on in-vivo diffuse reflectance spectroscopy measurements performed by a non-trained operator. In addition, we include simulation using
diffusion theory that explains the behavior of diffuse reflectance spectra with the increase of probe pressure.
The article is published in the original. 相似文献
135.
Joana Azeredo Ilia Ramos Ligia Rodriguks Rosrio Oliveira Jos Teixeira 《Journal of the Institute of Brewing》1997,103(6):359-361
Flocculation is a property of yeast cells that has been traditionally used in industrial fermentations, especially in the brewing and wine industries. It is a cell wall interaction and an increase in flocculation is strongly correlated with an increase in cell surface hydrophobicity . Methods to assay yeast cell surface hydrophobicity are only qualitative and while electrostatic interactions can play an important role, they are not always taken into account . In this work, a simple and accurate method based on contact angle measurements is described to determine yeast cell surface hydrophobicity. With this method, it is possible to quantify yeast cell surface hydrophobicity by determining the free energy of interaction between cells and water molecules. Several yeast strains with different flocculation characteristics have been used to validate the method . 相似文献
136.
A. Ibarz A.M. Ramos J. Puig-Bargués G.V. Barbosa-Cánovas 《Journal of food science》1998,63(6):1045-1048
Heat transfer characteristics were studied on clarified depectinized peach juices heated in an agitated jacketed vessel. Four types of agitators and several agitation rates were analyzed. Two equations were derived for the density and rheological behavior of peach juice based on the combined effects of temperature and soluble solids content. Overall and internal heat transfer coefficients were also determined. For each agitator, Nusselt number was statistically correlated as a function of the Reynolds and Prandtl numbers, and as the ratio of the fluid viscosity at the bulk temperature to the fluid viscosity at the wall temperature. The power number also correlated with the Reynolds, Froude, and time numbers. 相似文献
137.
Rotaviruses and reoviruses are involved in human and animal diseases. It is known that both viruses penetrate the gastrointestinal tract but their interaction with phagocytic cells is unknown. To study this interaction, peritoneal resident phagocytic cells were used and rotavirus and reovirus replication in peritoneal phagocytic cells was observed. However, rotavirus replication in these cells led to the production of defective particles since MA-104 cells inoculated with rotavirus phagocytic cell lysate did not show any evidence of virus replication. On the basis of these results, we suggest that, although reovirus dissemination may be helped by these phagocytic cells, these cells may control rotavirus infection and probably contribute to the prevention of its dissemination. 相似文献
138.
Linten D. Xiao Sun Carchon G. Jeamsaksiri W. Mercha A. Ramos J. Jenei S. Wambacq P. Dehan M. Aspemyr L. Scholten A.J. Decoutere S. Donnay S. De Raedt W. 《Solid-State Circuits, IEEE Journal of》2005,40(9):1922-1931
Wafer-level packaging (WLP) technology offers novel opportunities for the realization of high-quality on-chip passives needed in RF front-ends. This paper demonstrates a thin-film WLP technology on top of a 90-nm RF CMOS process with one 15-GHz and two low-power 5-GHz voltage-controlled oscillators (VCOs) using a high-quality WLP or above-IC inductor. The 5-GHz VCOs have a power consumption of 0.33 mW and a phase noise of -115 dBc/Hz and -111 dBc/Hz at 1-MHz offset, respectively, and the 15-GHz VCO has a phase noise of -105 dBc/Hz at 1-MHz offset with a power consumption of 2.76 mW. 相似文献
139.
Ana Maria Ramos Joaquim Vital Isabel F. Silva Humberto Valente Pedro T. Gomes 《Catalysis Letters》1998,51(1-2):117-119
The homopolymerisation of styrene is studied in the presence of Y, USY and beta zeolites. High molecular weight polymers,
in the range 0.7 × 106–1 × 106, are obtained in good yields. The activity of zeolite beta is only slightly increased by calcination of the as-synthesised
material, pointing to an important role of the zeolite outer surface. The influence of the catalyst acidity upon the polymer
molecular weight is evaluated by the use of dealuminated zeolites.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
140.
Medeiros Sara Fernandes Isabel Fournier Benoit Nunes João Carlos Ramos Violeta 《Bulletin of Engineering Geology and the Environment》2021,80(12):8949-8960
Bulletin of Engineering Geology and the Environment - The alkali-silica reaction (ASR) is a chemical deterioration of concrete that involves reactive forms of silica. Volcanic glass is one of the... 相似文献