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Structural and elastic properties of defect chalcopyrite HgGa2S4 under high pressure
2014
In this work, we focus on the study of the structural and elastic properties of mercury digallium sulfide (HgGa2S4) at high pressures. This compound belongs to the family of AB(2)X(4) ordered-vacancy compounds and exhibits a tetragonal defect chalcopyrite structure. X-ray diffraction measurements at room temperature have been performed under compression up to 15.1 GPa in a diamond anvil cell. Our measurements have been complemented and compared with ab initio total energy calculations. The axial compressibility and the equation of state of the low-pressure phase of HgGa2S4 have been experimentally and theoretically determined and compared to other related ordered-vacancy compounds. The pres…
An Analysis of the Broadening Induced by Beam Damage in Transmission Electron Diffraction Spots from an Oriented Aliphatic Monolayer
1991
We have analysed the progressive changes in diffraction spot shape during prolonged transmission electron diffraction observation of a soap monolayer supported on a thin polymer film. The material used to form the monolayer was cadmium eicosanoate (arachidate). The observed changes cannot be explained at all in terms of the chemical crosslinking which is known to occur as a result of beam damage, nor completely in terms of the strain fields caused by unbound dislocation defects of the crystalline lattice. The most plausible explanation involves the formation of linear dislocation aggregates which resemble grain boundaries but yet which are not linked into a continuous network. The evolution…
Digital Art History at the Crossroads
2022
Information and Communications Technologies, and more specifically online digital media, are revolutionizing the ways to produce and disseminate scientific knowledge. Humanities and social sciences -art history among them- are not alien to this process. The new challenges and opportunities have already generated a body of thinking and abundant case studies. Many of these applications have been exploratory, disconnected, and short-lived, but nonetheless very stimulating. This essay offers a report on the state of the conversation: a meeting at the crossroads, briefly outlining debates, agreements and disagreements, (dis)continuities with the broader framework of the discipline, and future pe…
Performance of a new real time digital pulse processing system for X-ray and gamma ray semiconductor detectors
2014
New generation spectroscopy systems have advanced towards digital pulse processing (DPP) approaches. DPP systems, based on direct digitizing and processing of detector signals, have recently been favoured over analog pulse processing electronics, ensuring better performance. In this work, we present the performance of a new real time DPP system for X-ray and gamma ray semiconductor detectors. The system is based on a commercial digitizer equipped with a custom DPP firmware, developed by our group, for on-line pulse shape and height analysis. X-ray and gamma ray spectra measurements with cadmium telluride (CdTe) and germanium (Ge) detectors, coupled to resistive feedback preamplifiers, will …
Mixed-type circuits with distributed and lumped parameters as correct models for integrated structures
1991
The technology of integrated circuits imposes upon their designers the need to deal with structures with distributed parameters. Figure 4.1 shows a schematic diagram of part of a digital integrated chip, consisting of an n MOS transistor with gate (G), drain (D) and source (S) as terminals, and its thin-film connection with the rest of the chip. This on-chip connection can be made by metals (Al, W), polycristaline silicon (polysilicon) or metal suicides (WSi 2 ). Alternative materials to oxide-passivated silicon substrates are saphire and gallium arsenide (Saraswat and Mohammadi [1982], Yuan et al. [1982], Passlack et al. [1990]).
Digital filtering and analysis for a semiconductor X-ray detector data acquisition
2007
Abstract Pile-up distortion is a major drawback in X-ray spectroscopy at high count rate. Pulse width narrowing with shaping techniques can lead to the reduction of the pile-up distortion, but a low shaping time reduces the noise filtration and leads to a poor energy resolution. Thus, only a best compromise solution between the pile-up and the noise requirements is achievable. The hardware manipulation needed to adjust the parameters of the traditional electronic shaping amplifiers makes it uneasy to tests various settings in different conditions. Digital techniques can help to overcome such difficulties. A digital signal processing and analysis system for X-ray spectroscopy is described in…
Recensione a D. BUZZATI, Le storie dipinte, a cura di L. Viganò, Milano Mondadori, 2013.
2014
Ultimo di una serie di raccolte buzzatiane il volume Le storie dipinte (2013, a cura di L. Viganò) manifesta l’intenzione assolutamente meritoria di riequilibrare nella percezione del grande pubblico lo scrittore e il pittore Dino Buzzati e si inserisce perfettamente nella logica editoriale di ampliamento della conoscenza delle molteplici attività artistiche di Buzzati.
Centering and Compound Conditionals under Coherence
2016
There is wide support in logic , philosophy , and psychology for the hypothesis that the probability of the indicative conditional of natural language, \(P(\textit{if } A \textit{ then } B)\), is the conditional probability of B given A, P(B|A). We identify a conditional which is such that \(P(\textit{if } A \textit{ then } B)= P(B|A)\) with de Finetti’s conditional event, B|A. An objection to making this identification in the past was that it appeared unclear how to form compounds and iterations of conditional events. In this paper, we illustrate how to overcome this objection with a probabilistic analysis, based on coherence, of these compounds and iterations. We interpret the compounds a…
Closedness and lower semicontinuity of positive sesquilinear forms
2009
The relationship between the notion of closedness, lower semicontinuity and completeness (of a quotient) of the domain of a positive sesquilinear form defined on a subspace of a topological vector space is investigated and sufficient conditions for their equivalence are given.