102,264 research outputs found
Handheld-Impedance-Measurement System with seven-decade capability and potentiostatic function
No full textThis paper describes design and test of a new impedance-measurement system for nonlinear devices that exhibits a seven-decade range and works down to a frequency of 0.01 Hz. The system is specifically designed for electrochemical measurements, but the proposed architecture can be employed in many other fields where flexible signal generation and analysis are required. The system employs an unconventional signal generator based on two pulsewidth modulation (PWM) oscillators and an autocalibration system that allows uncertainties of less than 3% to be obtained over a range of 1 kΩ to 100 GΩ. A synchronous demodulation processing allows the noise superimposed to the low-amplitude input signals to be made negligibl
Modified POF Sensor for Gaseous Hydrogen Fluoride Monitoring in the Presence of Ionizing Radiations
No full textThis paper describes the development of a sensor designed to detect low concentrations of hydrogen fluoride (HF) in gas mixtures. The sensor employs a plastic optical fiber (POF) covered with a thin layer of glass- like material. HF attacks the glass and alters the fiber transmission capability so that the detection simply requires a LED and a photodiode. The coated POF is obtained by means of low-pressure plasma-enhanced chemical vapor deposition that allows the glass-like film to be deposited at low temperature without damaging the fiber core. The developed sensor will be installed in the recirculation gas system of the resistive plate chamber muon detector of the Compact Muon Solenoid experiment at the Large Hadron Collider accelerator of the European Organization for Nuclear Research (CERN
Measurement Procedures for the Electrical Characterization of Oxide Thin Films
No full textThis paper describes a measurement system for the electrical characterization of oxide thin films. Such films can be produced using plasma-sputtering processes and permit the realization of a large set of high-performance components, such as capacitors, active devices, sensors, and protective coatings. The electrical properties of the oxide films, which have a thickness of less than 1 μm, are difficult to measure since very high resistances (on the order of gigaohms) and small capacitances (on the order of picofarads) are expected for contact areas smaller than 1 mm2. The measurement system and the procedures described in this paper represent an alternative solution to the commercial devices, which usually employ a mercury probe for performing the contact with the specimen under characterization. Furthermore, the proposed system can be used not only to estimate the electrical properties of a single point but to evaluate the uniformity of oxide films on large specimens as well. The experimental results reported refer to valve-metal-based oxide films deposited in a lab-scale capacitively coupled parallel-plate reactor and show the effectiveness of the proposed procedure
Pathology and molecular pathology of cholangiocarcinoma
No full textBiliary tract cancers are a wide group of heterogeneous neoplasms of the biliary tree, composed of intrahepatic cholangiocarcinoma perihilar bile duct cancer and distal bile duct cancer, according to location. The variability in location reflects the different morphologies and molecular alterations. In particular, intrahepatic peripheral mass forming cholangiocarcinoma is represented by the “small duct type” cholangiocarcinoma, which is different from the “large duct type” cholangiocarcinoma that, although intrahepatic, behaves similar to extrahepatic bile duct cancers, perihilar and distal ones. Recently, molecular targetable alterations, mainly FGFR2 fusions and IDH1 mutations, have been described, mostly in the intrahepatic “small duct type” subgroup and have opened the way, together with rarer targetable alterations, for personalisation of therapy also in these aggressive neoplasms
Analysis of the BE-EJTs results for the prediction of a Fuel Coolant Interaction Experiment
No full text"Preparation and characterization of cobalt(III)bipyridine and phenantrholine complexes"
No full text"Thin layer chromatographic and "in situ" spectrophotometric determination of products in solid-solid thermal reaction"
No full textPlanning in Developing Countries: a DSS Approach for Managing Water Resources In the Lushnjie District, Albania
No full text
On the Field Statistics in Nested Reverberation Chambers
No full textWe study the normalized field statistics inside nested reverberation chambers, through the analysis of the shielding effectiveness of enclosures and material samples. Accurate knowledge of field statistics allows to improve the estimation of probability distributions for high field values inside electrically large enclosures. Furthermore, the study allows for better selection of the measurement model for both shielding effectiveness of enclosures and materials and gaskets. We find the correct procedures to achieve such distributions. We study basic cases of single and electrically small coupling apertures filtering single or double field components and we show the theoretical statistics of the field components inside NRCs. The change of inner field distributions is driven by the electrical size of coupling apertures and has been verified experimentally. The theory developed to obtain such statistics is based upon physics and the results are supported by measurements. The procedures and results shown in this paper are applicable to predict the statistics in NRCs as well as in adjacent RCs
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