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71.
Salima Nadia Nasreddine Naima Rachid 《AEUE-International Journal of Electronics and Communications》2008,62(5):395-400
This article presents a set of accurate closed-form formulas for the electromagnetic parameters (inductance (L), capacitance (C) and characteristic impedance (Zc)) for squared coaxial lines with circular and square inner conductor. The analytical expressions, deduced from rigorous analysis by the finite element method (FEM), method of moments (MoM) and curves fitting techniques, can be easily implemented in CAD simulation tools, to design components for wireless communication. This study presents accurate and suitable general expressions for all squared coaxial lines with a wide range of outer to inner conductors ratio between 1.2 and 10. As an application, we present the design of 60 GHz branch line couplers. 相似文献
72.
Stripping methods studies for HVOF WC-10Co-4Cr coating removal 总被引:1,自引:0,他引:1
Richard Menini Nihad Ben Salah Rachid Nciri 《Journal of Materials Engineering and Performance》2004,13(2):185-194
The use of high-velocity oxyfuel (HVOF) cermet coatings is considered to be a valuable and innovative alternative technology
to replace Cr(VI) electroplating. Among others, a WC-10Co-4Cr coating is one of the best choices for landing gear components
due to its excellent tribology and corrosion properties. The stripping process of such a cermet coating was studied due to
its importance for the repair and overhaul of landing gear components. Stripping solutions fulfill the following criteria:
keep substrate integrity; exhibit a high strip rate (SR); lead to uniform dissolution; show no galvanic corrosion; and be
environmentally friendly. Three different high-strength steel substrates (4340, 300M, and Aermet100) were studied. Five different
stripping solutions were selected for the electrochemical study. Only three met the targeted criteria: the meta-nitrobenzane
sulfonate-sodium cyanide solution; the Rochelle salt; and a commercial nickel stripper. It was found that the process must
be electrolytic, and that ultrasonic agitation is needed to enhance the overall mass transport and removal of WC particles
and metallic matrix residues. When choosing the most efficient solution and conditions, the SR was found to be as high as
162 μm h−1, which is a very acceptable SR for productivity sake. 相似文献
73.
ABSTRACTThis article examines the relative impacts of anthropogenic interventions and global climate change on the dynamics of saltwater intrusion in highly urbanized coastal aquifers. For this purpose, simulations of the impacts of sea-level rise and abstraction scenarios for the near future were undertaken for a pilot aquifer using a multi-objective 3D variable-density flow and solute transport model. We find that sea-level rise associated with climate change has less influence on the encroachment of salinity than anthropogenic abstraction, which has a more appreciable impact on saltwater intrusion through greater sensitivity to water consumption and seasonality. 相似文献
74.
Bargach Walid Zidane Mustapha Benyoussef Abdelilah Ez-Zahraouy Hamid Laamara Rachid Ahl 《Journal of Superconductivity and Novel Magnetism》2022,35(2):331-338
Journal of Superconductivity and Novel Magnetism - Electronic and magnetic properties of CdS-based, doped by various transition metal elements (Ti, V, Cr, Mn, Fe, Co or Ni), dilute magnetic... 相似文献
75.
In this article, an extension of the spatial filter method to study Fabry‐Perot antennas with homogeneous or inhomogeneous partially reflecting surface (PRS) of finite size is proposed. This tool was subsequently validated through the study of different Fabry‐Perot antennas, with homogeneous PRS and inhomogeneous GRadient‐INdex (GRIN) PRS that present very high side lobe level (SLL). Since they are due to structure truncation, a new inhomogeneous PRS to reduce the SLL is designed with the new analytical tool. The new inhomogeneous PRS for Fabry‐Perot antenna is characterized by simulations and measurements. Compared to the homogeneous PRS antenna, the proposed PRS allows a SLL reduction of 5 dB without decreasing the 14 dBi directivity. 相似文献
76.
Hafri Mohamed Toumi Hechmi Lespessailles Eric Jennane Rachid 《Pattern Analysis & Applications》2020,23(2):581-591
Pattern Analysis and Applications - This paper investigates a 3D novel dual active contours approach to segment multiple regions in medical images. The locally based segmentation approaches can... 相似文献
77.
Mustapha El HANINE ;Elhassane ABDELMOUNIM ;Rachid HADDADI ;Abdelaziz BELAGUID 《计算机技术与应用:英文》2014,(2):98-104
The most common noises in ECG (electrocardiogram) signal processing are BW (baseline wandering) and the 50 or 60 Hz PLI (power line interferences). In order to remove these two major source of noises, we have used the recent powerful DWT (discrete wavelet transform) signal processing in ECG signals which are obtained from MIT-BIH Arrhythmia Database. The results indicate that DWT is a good method for filtering noises without changing the morphology of ECG, and can be applied to all types of ECG signals, whether normal or presenting arrhythmias. 相似文献
78.
This paper presents the abstraction of open consensus and argues for its use as an effective component for building reliable agreement protocols in practical asynchronous systems where processes and links can crash and recover. The specification of open consensus has a decoupled, on‐demand and re‐entrant flavour that make its use very efficient, especially in terms of forced logs, which are known to be major sources of overhead in distributed systems. We illustrate the use of open consensus as a basic building block to develop a modular, yet efficient, total‐order broadcast protocol. Finally, we describe our Java implementation of our open‐consensus abstraction and we convey our efficiency claims through some practical performance measures. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
79.
This study extends the boundary conditions of mediated contact theory by (a) differentiating between mediated contact quantity and quality, (b) examining whether mediated contact exerts effects above and beyond direct contact, and (c) offering causal and generalizable evidence on the effects of exposure to numerous individual outgroup members in news media. We match individual‐level data from a representative panel survey with data on the amount of coverage about members from two outgroups and with the results from validated sentiment analysis. Mediated contact, and especially its quantity, improved outgroup attitudes independently of direct contact. These findings emerged for both outgroups and across two outcome measures. 相似文献
80.