Search results for "electronics"
showing 10 items of 4340 documents
Intrinsic Point Defects in Silica for Fiber Optics Applications
2021
Due to its unique properties, amorphous silicon dioxide (a-SiO2) or silica is a key material in many technological fields, such as high-power laser systems, telecommunications, and fiber optics. In recent years, major efforts have been made in the development of highly transparent glasses, able to resist ionizing and non-ionizing radiation. However the widespread application of many silica-based technologies, particularly silica optical fibers, is still limited by the radiation-induced formation of point defects, which decrease their durability and transmission efficiency. Although this aspect has been widely investigated, the optical properties of certain defects and the correlation betwee…
Investigation of the Thermomechanical Response of Cyclically Loaded NiTi Alloys by Means of Temperature Frequency Domain Analyses
2021
Nickel–Titanium (NiTi) shape memory alloys subjected to cyclic loading exhibit reversible temperature changes whose modulation is correlated with the applied load. This reveals the presence of reversible thermomechanical heat sources activated by the applied stresses. One such source is the elastocaloric effect, accounting for the latent heat of Austenite–Martensite phase transformation. It is, however, observed that when the amplitude of cyclic loads is not sufficient to activate or further propagate this phase transformation, the material still exhibits a strong cyclic temperature modulation. The present work investigates the thermomechanical behaviour of NiTi under such low-amplitude cyc…
Multivariate Assessment of Procedures for Molecularly Imprinted Polymer Synthesis for Pesticides Determination in Environmental and Agricultural Samp…
2021
In the case of quantitative and qualitative analysis of pesticides in environmental and food samples, it is required to perform a sample pre-treatment process. It allows to minimalize the impact of interferences on the final results, as well as increase the recovery rate. Nowadays, apart from routinely employed sample preparation techniques such as solid-phase extraction (SPE) or solid-phase microextraction (SPME), the application of molecularly imprinted polymers (MIPs) is gaining greater popularity. It is mainly related to their physicochemical properties, sorption capacity and selectivity, thermo-mechanical resistance, as well as a wide range of polymerization techniques allowing to obta…
Improved time-resolved acousto-optic technique for optical fiber analysis of axial non-uniformities by using edge interrogation
2015
The time-resolved acousto-optic technique demonstrated recently to be a very useful method for the analysis of fiber axial non-uniformities, able to detect variations of fiber diameter in the nanometric scale with a spatial resolution of few cm. An edge interrogation approach is proposed to improve further the performance of this technique. The detection of subnanometer fiber diameter changes or sub-ppm changes of the core refractive index is demonstrated.
Microwave-free magnetometry with nitrogen-vacancy centers in diamond
2016
We use magnetic-field-dependent features in the photoluminescence of negatively charged nitrogen-vacancy centers to measure magnetic fields without the use of microwaves. In particular, we present a magnetometer based on the level anti-crossing in the triplet ground state at 102.4 mT with a demonstrated noise floor of 6 nT/$\sqrt{\text{Hz}}$, limited by the intensity noise of the laser and the performance of the background-field power supply. The technique presented here can be useful in applications where the sensor is placed closed to conductive materials, e.g. magnetic induction tomography or magnetic field mapping, and in remote-sensing applications since principally no electrical acces…
Optical quenching and recovery of photoconductivity in single-crystal diamond
2017
We study the photocurrent induced by pulsed-light illumination (pulse duration is several nanoseconds) of single-crystal diamond containing nitrogen impurities. Application of additional continuous-wave light of the same wavelength quenches pulsed photocurrent. Characterization of the optically quenched photocurrent and its recovery is important for the development of diamond based electronics and sensing. (C) 2017 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license. This work was supported by AFOSR and the DARPA QuASAR program, by NSF Grant No. ECCS-1202258, and by DFG through the DIP program (FO 703/2-1).
Influence of Temperature on Characteristics of Particulate Matter and Ecological Risk Assessment of Heavy Metals during Sewage Sludge Pyrolysis
2021
The formation process of Particulate Matter (PM) during sludge pyrolysis at different temperatures (300–700 °C) and the ecological risks of heavy metals were studied. The results showed that the particulate matter is mainly condensed on the quartz film in a carbon-based organic matter when the pyrolysis temperature was between 200–500 °C in a volatilization process. Inorganic particles was found in the particulate matter when the temperature was raised to 500–700 °C in a decomposition stage. Heavy metals were enriched in particulate matter with increase in pyrolysis temperature. When the temperature reached 700 °C, the concentration of Pb and Cd in the particulate matter significantly incre…
Oxidation State and Local Structure of Chromium Ions in LaOCl
2021
This research is funded by the Latvian Council of Science, project “Novel transparent nanocomposite oxyfluoride materials for optical applications”, project No. LZP-2018/1-0335. Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017- TeamingPhase2 under grant agreement No. 739508, project CAMART2.
Fabrication of CZTSe/CIGS Nanowire Arrays by One-Step Electrodeposition for Solar-Cell Application
2021
The paper reports some preliminary results concerning the manufacturing process of CuZnSnSe (CZTSe) and CuInGaSe (CIGS) nanowire arrays obtained by one-step electrodeposition for p-n junction fabrication. CZTSe nanowires were obtained through electrodeposition in a polycarbonate membrane by applying a rectangular pulsed current, while their morphology was optimized by appropriately setting the potential and the electrolyte composition. The electrochemical parameters, including pH and composition of the solution, were optimized to obtain a mechanically stable array of nanowires. The samples were characterized by scanning electron microscopy, Raman spectroscopy, and energy-dispersion spectros…
Shedding Light on Graphene Quantum Dots: Key Synthetic Strategies, Characterization Tools, and Cutting-Edge Applications
2021
During the last 20 years, the scientific community has shown growing interest towards carbonaceous nanomaterials due to their appealing mechanical, thermal, and optical features, depending on the specific nanoforms. Among these, graphene quantum dots (GQDs) recently emerged as one of the most promising nanomaterials due to their outstanding electrical properties, chemical stability, and intense and tunable photoluminescence, as it is witnessed by a booming number of reported applications, ranging from the biological field to the photovoltaic market. To date, a plethora of synthetic protocols have been investigated to modulate the portfolio of features that GQDs possess and to facilitate the…