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Formation Mechanism of Elemental Te Produced in Tellurite Glass Systems by Femtosecond Laser Irradiation
Get PDFThe formation of elemental trigonal tellurium (t-Te) on tellurite glass surfaces exposed to femtosecond laser pulses is discussed. Specifically, the underlying elemental crystallization phenomenon is investigated by altering laser parameters in common tellurite glass compositions under various ambient conditions. Elemental crystallization of t-Te by a single femtosecond laser pulse is unveiled by high-resolution imaging and analysis. The thermal diffusion model reveals the absence of lattice melting upon a single laser pulse, highlighting the complexity of the phase transformation. The typical cross-section displays three different crystal configurations over its depth, in which the overall thickness increases with each subsequent pulse. The effect of various controlled atmospheres shows the suppressing nature of the elemental crystallization, whereas the substrate temperature shows no significant impact on the nucleation of t-Te nanocrystals. This research gives new insight into the elemental crystallization of glass upon femtosecond laser irradiation and shows the potential to fabricate functional transparent electronic micro/nanodevices
Enhancing the performance and mechanical stability of 2D-based hybrid micro-supercapacitors using dendritic-gold as framework layer
No full textIn recent years scaling-down approaches on supercapacitors has led to the definition of Micro-Supercapacitors (μSC). The demand for these devices is increasing for many applications in microelectronics, such as wearable energy storage and self-powered sensors. Recently, many efforts have been made to achieve good results in terms of power and energy densities. However, the current research challenge is to develop a sustainable chain production, involving eco-friendly materials, such as water-based electrolytes, organic binders and low-impact active material. This work presents a hybrid μSC using low impact materials and a fully water-based solution. Different approaches were adopted for patterning the current collectors and for the deposition of the active materials. The material chosen as anode was MnO2 deposited by electroplating, which presents pseudocapacitive behavior. The active material used for the cathode was Activated Carbon (AC), deposited by drop-casting, which works through the electric double layer (EDL) capacitance effect. The electrolyte was 1 M Na2SO4 in water. We investigated the addition of an interlayer micro-structure made of Dendritic-Gold (D-Gold). The results show that such a layer seems to have positive effects in terms of wettability and mechanical stability, enhancing the adhesion of the active material. Electron microscopy measurement shows the characteristic tree-like shape of the layer. The device reports a capacitance of about 14 to 23 mF cm-2 and a large voltage window equal to 1.6 V. The present research explores, for the first time, the effects of dendritic gold in planar electrochemical capacitors. The findings should give an important contribution for boost energy storage densities in the field of 2D micro-supercapacitors
Application of Statistical Tools to Optimize a Dual Source Electrical High Dc Resistance Bridge
Get PDFAt the Istituto Nazionale di Ricerca Metrologica (INRIM), a commercial dual source high resistance bridge has been optimized by means of the application of statistical tools and of the analysis of measurements distributions. These tools help to achieve the best precision for resistance ratio measurements in the range 10 T & OHM; & DIVIDE; 100 T & OHM;. A measurement procedure consisting of multiple steps, in which at each one the value of the resistor under calibration is updated and has been considered the best one. With this procedure, at the third step, the lowest standard deviation of the mean and the measurements distribution approximately normal are obtained regardless of the settle time, of the resistance ratio, of the measurement voltages and of the resistors under comparison. This comes from the achievement of the white noise regime and from a bridge balance close to the ideal. This measurement procedure therefore allows also to achieve the lowest measurement uncertainty due to the minimization of the type A uncertainty. The Allan variance and the power spectral density were used to identify the white noise analyzing the detector readings. Strict triangulation rules were also established and applied to validate both the measurement process and the chosen model to extrapolate the values of the standard resistors at low voltages
Analytical prediction of floating floors impact sound insulation including thickness-resonance wave effects
No full textThe floating floor technology in buildings is increasingly used to achieve national acoustic and thermal insulation requirements, combining different compositions of materials and components with proper technical features. However, the analytical models nowadays available do not allow to estimate with the due accuracy the actual acoustic performance of floating floors with a thick or heavy resilient layer from involved material properties. The physical model presented in this paper, based on the vibration transmissibility theory, improves the prediction of the effect of a floating screed on the impact sound insulation, as a function of frequency, by taking into account the thickness-resonance wave effects in the resilient layer. The model is based on the exact analytical solution of the one-dimensional wave equa-tion in elastic media. Theoretical results are compared with existing computational models and with experimental data of impact sound insulation. (c) 2023 Elsevier Ltd. All rights reserved
Dy3+- and Pr3+-doped phosphate glass optical fibres for laser emission at visible wavelengths
Get PDFVisible lasers find applications in many fields such as medicine, materials processing, display and entertainment technology, microscopy and scientific research
ERRORS IN GONIOPHOTOMETRIC CHARACTERISATION OF SURFACES
No full textThe measurement of the spatial distribution of the luminance coefficient, called the q coefficient or BRDF (Bidirectional Reflectance Distribution Function), allows an accurate evaluation of the light-to-material interaction. The paper presents the analysis of the metrological performances of goniophotometers used in road luminance coefficient measurements, evaluating the errors introduced by the divergences of the light source and detector optical systems. In the case of road surface measurements, the large dimension of typical samples and the geometrical measurement constraints (lighting and viewing directions) are such that the instrument optical divergence introduces systematic errors, difficult to foresee if the sample BRDF is completely unknown
Orientation paper: suggestions to develop research projects in testing and measurements for the upcoming European Partnership on Metrology (EPM) Calls in 2024
Get PDFThe purpose of the document, in agreement with EMN-Q mission to support competitiveness
and innovation of the emerging European Quantum Industry by metrology science, services, and
knowledge transfer, is to identify the priorities related to the development of quantum technologies at the European Level. The EMN-Q is ideally positioned to identify the gaps in measurement capabilities and standards necessary for advancing quantum technologies and to collaboratively develop the solutions necessary to serve the rapidly growing needs of stakeholders. This orientation paper is particularly focused on the Calls Digital Transformation and Normative.
This orientation paper is based on three main elements:
the European Digital Strategy,
the EMN-Q strategic Research Agenda,
the “Standardization Roadmap on Quantum Technologies written by the CEN-CENELEC
Focus Group on Quantum Technologies (FGQT)” (Document FGQT Q04 Release 1 – March 2023
Micromagnetic simulation of electrochemically deposited Co nanowire arrays for wideband microwave applications
Get PDFWe study the magnetic properties of arrays of Co nanowires which exhibit zero bias-field ferromagnetic resonance absorptions in a 0-30 GHz range. Columnar arrays of Co nanowires with lengths of 8-15 mu m were electrochemically grown using similar to 20 mu m thick anodic alumina membranes with 50 nm pore diameters. Microstructural, static magnetic, and microwave properties of five different nanowire arrays were characterized. The studied Co nanowires present different crystal structure textures and magnetic properties. The static magnetic loop shapes and the ferromagnetic resonance frequencies of the nanowire arrays were correctly reproduced using the Mumax3 micromagnetic software. For each sample input parameters dependent on the x-ray diffraction and microstructural data, were fine-tuned to allow the best fit of the experimental hysteresis loops and the related microwave spectra. Using this method, it was possible to analyze the rather complex interplay between geometry and magneto-structural features of the different arrays, defining which parameters play a key role in the development of nano-systems with specific microwave properties
