Current Issue : April - June Volume : 2015 Issue Number : 2 Articles : 5 Articles
Magnetic flux leakage (MFL) as an efficient method for pipeline flaw detection plays important role in pipeline safety. This\nnondestructive test technique assesses the health of the buried pipeline. The signal is gathered by an array of hall-effect sensors\ndisposed at the magnetic neutral plane of a pair of permanent magnet in the pipeline inspection gauge (PIG) clinging to the inner\nsurface of the pipe wall.Themagnetic fluxmeasured by the sensors reflects the health condition of the pipe.The signal is influenced\nby not only the condition of the pipe, but also by the lift-off value of the sensors and various properties of electronic component.\nThe consistency of the position of the sensors is almost never satisfied and each sensor measures differently. In this paper, a new\nscheme of channel equalization is proposed for MFL signal in order to correct sensor misalignments, which eventually improves\naccuracy of defect characterization. The algorithm proposed in this paper is adaptive to the effects of error on the disposition of\nthe sensor due to manufacturing imperfections and movements of the sensors.The algorithm is tested by data acquired from an\nexperimental pipeline.The results show the effectiveness of the proposed algorithm....
Hydrogenated nanocrystalline Silicon thin films prepared by the very high frequency chemical vapor deposition technique (VHFCVD) on stainless steel (SST) substrates are used to design Schottky point contact barriers for the purpose of solar energy conversion and passive electronic component applications. In this process, the contact performance between SST andM(M = Ag, Au, and Ni) and between Ag, Au, and Ni electrodes was characterized by means of current-voltage, capacitance-voltage, and light intensity dependence of short circuit (Isc) current and open circuit voltage (Voc) of the contacts. Particularly, the devices ideality factors, barrier heights were evaluated by the Schottky method and compared to the Cheung�s. Best Schottky device performance with lowest ideality factor suitable for electronic applications was observed in the SST/nc-Si:H/Ag structure. This device reflects a V oc of 229mV with an I sc of 1.6 mA/cm2 under an illumination intensity of ?40 klux. On the other hand, the highest Isc being 9.0 mA/cm2 and the V oc of 53.1mV were observed for Ni/nc-Si:H/Au structure. As these voltages represent the maximum biasing voltage for some of the designed devices, the SST/nc-Si:H/M and M/nc-Si:H/M can be regarded as multifunctional self-energy that provided electronic devices suitable for active or passive applications....
The saturation regime of two types of fully depleted (FD) SOIMOSFET devices was studied.Ultra thin body (UTB) and gate recessed\nchannel (GRC) devices were fabricated simultaneously on the same silicon wafer through a selective ââ?¬Å?gate recessedââ?¬Â process. They\nshare the same W/L ratio but have a channel film thickness of 46nm and 2.2 nm, respectively. Their standard characteristics\n(IDS-VDS and IDS-VGS) of the devices were measured at room temperature before cooling down to 77K. Surprisingly, their respective\ntemperature dependence is found to be opposite. In this paper, we focus our comparative analysis on the devicesââ?¬â?¢ conduction using\na Y-function applied to the saturation domain. The influence of the temperature in this domain is presented for the first time.We\npoint out the limits of the Y-function analysis and show that a new function called Z can be used to extract the series resistance in\nthe saturation regime....
This work deals with the assessment of gate dielectric for 4H-SiC MOSFETs using technology based two-dimensional numerical\ncomputer simulations. Results are studied for variety of gate dielectric candidates with varying thicknesses using well-known\nFowler-Nordheim tunnelingmodel.Compared to conventional SiO2 as a gate dielectric for 4H-SiCMOSFETs, high-k gate dielectric\nsuch as HfO2 reduces significantly the amount of electric field in the gate dielectric with equal gate dielectric thickness and hence\nthe overall gate current density. High-k gate dielectric further reduces the shift in the threshold voltage with varying dielectric\nthicknesses, thus leading to better process margin and stable device operating behavior. For fixed dielectric thickness, a total shift in\nthe threshold voltage of about 2.5Vhas been observedwith increasing dielectric constant fromSiO2 (k = 3.9) toHfO2 (k = 25). This\nfurther results in higher transconductance of the device with the increase of the dielectric constant fromSiO2 toHfO2. Furthermore,\n4H-SiCMOSFETs are found to be more sensitive to the shift in the threshold voltage with conventional SiO2 as gate dielectric than\nhigh-k dielectric with the presence of interface state charge density that is typically observed at the interface of dielectric and 4H-SiC\nMOS surface....
In many applications, the electronic component is not continuously but only intermittently overloaded (e.g., inrush current, short\ncircuit, or discharging interference).With this paper,we provide insight into carbon resistors that have to hold out a rarely occurring\ntransient overload. Using simple electrical circuit, the resistor is overheating with higher current than declared, and dissipation is\nobserved by a thermal camera...
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