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Addressing of imperfection of a hybrid pixel sensor for X-ray detection with a circuit for charge sharing cancellation implemented
摘要： A developing trend in the design of event-driven sensors for X-ray detection are hybrid pixel detectors working in the single photon counting mode. The factors limiting detector performance, especially for small pixel sizes, include among others, mismatch of circuit components due to process variations, electronic noise and charge sharing. Charge sharing in a hybrid pixel detector occurs when the charge generated in X-ray photon interaction with a sensor is collected by more than one pixel. Charge sharing effect may significantly impair the detector energy resolution and result in counting extra events or missing some of the events. The impact of the charge sharing increases with a decrease of the pixel sizes. The small pixel size is a desired feature of a novel hybrid X-ray detector, as it allows better spatial resolution and helps to overcome the high count rate limits by accepting more photons per unit area. Therefore, the charge sharing effect must be dealt with by a dedicated readout IC or processed off-chip. Minimization of the analog parameters dispersion in the pixel matrix is crucial for the circuits designed for charge sharing cancellation. The chip’s sensitivity to the analog parameters spread and mitigation of the performance achieved with the digital correction blocks are studied. The DC offsets and gains spread can be optimized using correction circuits and dedicated trimming algorithms. Detection efficiency in case of charge sharing for the corrected and uncorrected pixel matrix is addressed. The simulation results as well as pencil beam measurements using synchrotron radiation are presented.
关键词： Front-end electronics for detector readout,Analogue electronic circuits,Digital electronic circuits
更新于2025-09-23 15:23:52
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Structures and electronic properties of Cu <i> <sub/>m</sub></i> Co <i> <sub/>n</sub></i> O <sub/>2</sub> ( <i>m</i> ? <i>+</i> ? <i>n</i> ?=?2–7) clusters
摘要： A theoretical study was carried out of CumConO2(2 ≤ m + n ≤ 7) clusters using density functional method. O2 molecules are adsorbed at top sites. After adsorption, O2 molecules are activated. The Δ2E value of CuCo3O2 cluster is obviously the smallest, indicating that its thermodynamic stability is the worst. While Cu6CoO2 displays stronger chemical stability. Charge transfer from Cu–Co to anti-bonding orbital of O2, which leads to O–O getting longer. The Mulliken charge population and PDOS analysis are also discussed.
关键词： electronic properties,O2 adsorption,density functional theory,structures and stability
更新于2025-09-23 15:23:52
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Molecular structure, NBO analysis, ?rst hyper polarizability, and homo-lumo studies of π-extended tetrathiafulvalene (EXTTF) derivatives connected to π-nitro phenyl by density functional method
摘要： In these study we have been obtained the structural properties of (exTTF) derivatives 1-4 by using B3LYP/6-31G(d,p) of Density Functional Theory (DFT) utilizing Becke three exchange functional and Lee Yang Paar correlation functional. The calculation of first hyperpolarizability shows that the molecules are attractive molecules for future applications in non-linear optics. Molecular electrostatic potential (MEP) at a point in the space around a molecule gives an indication of the net electrostatic effect produced at that point by the total charge distribution of the molecule. The calculated HOMO and LUMO energies show that charge transfer occurs within these molecules.
关键词： Density Functional Theory,Quantum Chemical Calculations,Computational Chemistry,Electronic Structure,Tetrathiafulvalenes
更新于2025-09-23 15:23:52
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Métodos para a tomada de decis?o em portfólio de produtos: um levantamento em empresas dos setores eletr?nico, óptico e de informática
摘要： Decision making in product portfolio is a relevant aspect, not only to the good performance of product development, but also to support in the process of business strategy. This article has the objective to present and analyze the main methods for decision making in product portfolio used by large and medium enterprises that operate in Brazil, in electronic, optical and computer sectors. A survey research was conducted in a sample of 40 companies. It was noted, that most of these companies, especially the middle sized companies, followed an informal pattern for decision-making in product portfolio, which is guided, mainly, by the perception of senior management. Among the employed formal methods, financial, market research and mapping methods are the most present in the surveyed sectors.
关键词： Process of Product Development,Survey research,Methods for Decision Making,Product Portfolio Management,Electronic, optical and computing companies
更新于2025-09-23 15:23:52
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The influence of nitrogen doping on the electronic structure of the valence and conduction band in TiO <sub/>2</sub>
摘要： X-ray emission spectroscopy (XES) and X-ray absorption spectroscopy (XAS) provide a unique opportunity to probe both the highest occupied and the lowest unoccupied states in matter with bulk sensitivity. In this work, a combination of valence-to-core XES and pre-edge XAS techniques are used to determine changes induced in the electronic structure of titanium dioxide doped with nitrogen atoms. Based on the experimental data it is shown that N-doping leads to incorporation of the p-states on the occupied electronic site. For the conduction band, a decrease in population of the lowest unoccupied d-localized orbitals with respect to the d-delocalized orbitals is observed. As confirmed by theoretical calculations, the N p-states in TiO2 structure are characterized by higher binding energy than the O p-states which gives a smaller value of the band-gap energy for the doped material.
关键词： TiO2 doping,X-ray absorption spectroscopy,electronic structure analysis,X-ray emission spectroscopy
更新于2025-09-23 15:23:52
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Photocatalytic activity of biosynthesized CeO2 nano particles
摘要： This paper focuses on a cost effective and environment friendly technique for green synthesis of cerium oxide (CeO2) nano particles from cerium (III) nitrate hexahydrate solution by co-precipitation method using the leaf extract of different species of Artemisia pallens which acts as reducing and capping agent. The prepared CeO2 nano particles were characterized by XRD, TEM, FTIR, UV–Vis spectroscopy. The Photocatalytic activity of the prepared ceria powders was determined by their ability to degrade Methylene blue solution under UV-light radiation. The photo degradation result observed with 10 mg/L ceria at pH = 11 for 180 min have highest output and pseudo 1st order rate constant was 0.983.
关键词： Nanoparticles,Photocatalysis,Electronic material,Cerium oxide
更新于2025-09-23 15:23:52
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Structural, Electronic and Mechanical Properties of Perovskite Oxides LaMO<sub>3</sub> (M = Mn, Ni) Compounds in the High and Low Symmetric Phases by First Principle Calculation
摘要： The widely investigated perovskite oxides has attracted for a long time a great interest on the physical properties, in their bulk structures as well as the heterostructures components. The Lanthanum transition metal oxides LaMO3 (M= Transition metal) is part of, due to their potential use in advanced technology (including superconductivity, magnetoresistance, ionic conductivity, and a multitude of dielectric properties). Despite the broad exploration of the physical properties, we found a considerable lack in the investigation of the mechanical properties of the LaMO3 compounds. By applying the Density Functional Theory (DFT), we shed light on the structural, electronic, and especially mechanical properties of the experimentally verified phases of The LaMnO3, and LaNiO3. We first calculated the structural and electronic properties, then we continue with the single-crystal elastic constants and mechanical properties, where the bulk, shear and Young’s moduli, and the Anisotropy indexes were deduced, in order to remedy the existing gap of the theoretical knowledge about the mechanical behavior of the LaMnO3, and LaNiO3 compounds.
关键词： Density Functional Theory,Mechanical properties,Perovskite oxides,Electronic properties
更新于2025-09-23 15:23:52
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Electronic Structure of Chlorophyll a Solution Investigated by Photoelectron Yield Spectroscopy
摘要： Various bio-related processes are driven by electron transfer reactions. Therefore the electronic structures of bio-molecules in their living environment are keys of their functionalities. One significant example photosynthesis which has attracted much attention due to urgent necessity of clean energy source. In this study, we carried out photoelectron yield spectroscopy (PYS) measurements to demonstrate the electronic structures of oligomerizedChl-a molecules, which is known as an essential reaction center of the photosystem in general green plants, under the atmospheric environment. The ionization energies of the Chl-a aggregates are successfully derived.
关键词： Photoelectron Yield Spectroscopy,Polarization energy,Light harvesting antenna,Photosynthesis,Photosystem,Electronic structure,Ionization energy,Reaction center,Chlorophyll a
更新于2025-09-23 15:23:52
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Application of polar solvent effects in absorption spectra for determination of lowest electron-excited states of phthalide
摘要： The optical absorption spectra of phthalide in polar (methanol) and nonpolar (n-hexane) solvents are recorded. The electronic phthalide spectrum was calculated by TDDFT B3LYP/6-311+G(d, p) using the polarisable continuum model. Based on an analysis of calculation data and the displacement of absorption bands in a polar solvent, it was established that the absorption bands of phthalide at energies of 3.51 and 3.96 eV correspond to singlet-triplet transitions to the T1 and T2 states, respectively.
关键词： Triplet excited states,Electronic absorption spectra,PCM TDDFT,Solvent effect,Phthalide
更新于2025-09-23 15:23:52
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Elastic, electronic and thermoelectric properties of Sr3MN (M?= Sb, Bi) under pressure
摘要： We have performed first-principles calculations to study the structural, elastic, electronic and thermoelectric properties of Sr3MN (M = Sb, Bi) under pressure. The optimized lattice parameters are in good agreement with the available experimental and theoretical measurements. Brittle to ductile transition occurs at 15 GPa and the hardness of both compounds decreases with the increase of pressure. The band gap slightly reduces with pressure and both compounds exhibit semiconducting nature for TB-mBJ potential. The density of states increases slightly at the Fermi level. The inclusion of the spin-orbit coupling effect reduces the band gap of Sr3BiN. The calculated Seebeck coefficient for Sr3SbN and Sr3BiN at 15 GPa and 600 K are 257 and 142 μV/K, respectively. The calculated lattice thermal conductivity of both compounds decreases with the increase of pressure, as phonon scattering increased. The predicted thermoelectric figure of merit (ZT) for Sr3SbN and Sr3BiN at 15 GPa and 600 K are 0.71 and 0.63, respectively. The obtained thermoelectric properties at high pressure making them suitable for thermoelectric device applications.
关键词： Lattice thermal conductivity,Pressure effect,Thermoelectric properties,Electronic properties,Elastic properties
更新于2025-09-23 15:23:52