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In this effort, a two-dimensional photonic crystal ring resonator (2DPCRR) is simulated. This device is developed for temperature detection in harsh enviro 相似文献
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Anmar W. Sabri Zainab H. Ali Serwan F. Shawkat Lamia A. Thejar Thaer I. Kassim Khalid A. Rasheed 《河流研究与利用》1993,8(3):237-250
The influences of the Samarra impoundment on the ecology of the downstream sector of the river Tigris are investigated. Zooplankton were collected monthly from July 1987 to July 1988. It was found that zooplankton were most abundant during high river discharges in March. During the month of low river discharge, September, the zooplankton population was greatly reduced immediately below the barrage and remained so to the last downstream station. Several factors seem to explain such differences. The high discharge from the impoundment was found to be the dominating factor and may flush the small backwaters in which zooplankton were abundant, thus increasing the population in the river. Zooplankton species vary in their ability to sustain populations in the river, variations which are due mainly to species-specific characteristics. 相似文献
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In the power transformer, the presence of polar or charged species in the insulating oil can cause failure and electric discharges. Solid substrates such as silica can be used to extract the polar species and to refine the oil in order to prevent future failure in the power transformer. However, the use of silica for petroleum oil separation and refining will depend on the silica characteristics such as surface charge, surface composition, specific surface area and particle size.Various pyrogenic silicas having various specific surface areas (49-200 m2 g−1) and particle sizes (207-500 nm) were used to extract the polar fractions from the neat transformer insulating oils (a new, NO, and used, UO2, oils). The oil covered silica samples were investigated by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy in the range 4000-600 cm−1. The bare silica surfaces present two main hydroxyl components, a sharper peak at 3745 cm−1, I3745, due to isolated silanols and a second broad, which spreads over 3745-3000 cm−1, I3745-3000, due to H-bonded silanols. The relative intensities of the two components, I3745/I3745-3000, varied for the bare and the oil covered silicas depending on the solid surface characteristics. The adsorption of the NO polar fraction onto silica leads to strong reduction in intensity of the sharper peak in favour of the broad one. However, the adsorption of the UO2 polar fraction onto silica leads in all cases to the decrease in the intensity of the both silica OH components. Further, the UO2 adsorption on the silica leads to the apparition of a broad peak at low frequency in the region 3250-3300 cm−1 which, is due to the associated phenolic groups of UO2 oil polar fraction. The analysis of the DRIFT spectra for various samples indicates that the oil polar fraction resembles to asphaltenes compounds.The microelectrophoresis method used to investigate the surface charge at the water/oil polar fraction covered silica interface, indicates negatively charged particles. Further, the negative charge increased with the pH, as resulting from the increase of the ionisation and/or the amount of the oil polar carboxylic and phenolic groups. The oil polar fraction, i.e. the asphaltene components, in contact with both the silica surface and water at high pH values rearrange, due to their amphiphilic character.Finally, the use of the silica substrates seems to be suited to extract and analyse polar species present in petroleum oil. A correlation is found between the nature of the oil, its functionalities, and the magnitude of its zeta potential value at the water/oil covered silica interface. 相似文献
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J. Charlier S. Ameur J.P. Bourgoin C. Bureau S. Palacin 《Advanced functional materials》2004,14(2):125-132
This work presents a new one‐step process enabling the mask‐free localized functionalization by organic polymers of the conducting or semiconducting parts of composite surfaces at the micrometer and submicrometer scale. The functionalization is carried out via cathodic electrografting of suitable precursors of composite cathodes, which gives an insulating polymer film strongly grafted to selected parts of the composite electrodes and guarantees that the resolution is that of the pre‐existing pattern, even when the whole surface is dipped into the reaction medium. The presumed mechanism is based on a regioselective extraction of electrons from the composite surface according to its apparent local work function in solution. 相似文献
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We developed a method for determination of motor conduction along the mandibular and sensory conduction along the lingual and inferior alveolar nerves in 10 controls and 6 patients with lingual neuropathy following lower wisdom tooth extraction. Patients with lingual neuropathy had reduced/absent or delayed compound sensory action potentials and normal conduction along the fibers of the inferior alveolar nerve and mandibular nerve. The method provides a useful electrophysiological means of evaluating lingual nerve lesions. 相似文献
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1,12-bis(1,2,4-triazolyl)dodecane (dTC12) is an excellent corrosion inhibitor for carbon steel in deaerated 1 M HCl solution. In this work electrochemical and analytical techniques were used to study the inhibition of corrosion on carbon steel in acidic medium. The carbon steel corrosion inhibition of dTC12 was attributed to the synergistic effect between chloride anion and quaternary ammonium ion. The protective efficiency of the film was higher than 90%, indicating that corrosion of carbon steel in 1 M HCl is reduced by dTC12.The effect of dissolved oxygen on the inhibition efficiency was also investigated. The results show that the inhibition efficiency increases in early stage and decreases for a long immersion time. 相似文献
10.
This paper deals with state estimation problem for uncertain continuous‐time systems. A numerical treatment is proposed for designing interval observers that ensures guaranteed upper and lower bounds on the estimated states. In order to take into account possible perturbations on the system and its outputs, a new type of interval observers is introduced. Such interval observers consist of two coupled general Luenberger‐type observers that involve dilatation functions. In addition, we provide an optimality criterion in order to find optimal interval observers that lead to tight interval error estimation. The proposed existence and optimality conditions are expressed in terms of linear programming. Also, some illustrative examples are given. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献