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Advanced Ultraviolet Radiation and Ozone Retrieval for Applications (AURORA): A Project Overview
摘要： With the launch of the Sentinel-5 Precursor (S-5P, lifted-off on 13 October 2017), Sentinel-4 (S-4) and Sentinel-5 (S-5)(from 2021 and 2023 onwards, respectively) operational missions of the ESA/EU Copernicus program, a massive amount of atmospheric composition data with unprecedented quality will become available from geostationary (GEO) and low Earth orbit (LEO) observations. Enhanced observational capabilities are expected to foster deeper insight than ever before on key issues relevant for air quality, stratospheric ozone, solar radiation, and climate. A major potential strength of the Sentinel observations lies in the exploitation of complementary information that originates from simultaneous and independent satellite measurements of the same air mass. The core purpose of the AURORA (Advanced Ultraviolet Radiation and Ozone Retrieval for Applications) project is to investigate this exploitation from a novel approach for merging data acquired in different spectral regions from on board the GEO and LEO platforms. A data processing chain is implemented and tested on synthetic observations. A new data algorithm combines the ultraviolet, visible and thermal infrared ozone products into S-4 and S-5(P) fused profiles. These fused products are then ingested into state-of-the-art data assimilation systems to obtain a unique ozone profile in analyses and forecasts mode. A comparative evaluation and validation of fused products assimilation versus the assimilation of the operational products will seek to demonstrate the improvements achieved by the proposed approach. This contribution provides a first general overview of the project, and discusses both the challenges of developing a technological infrastructure for implementing the AURORA concept, and the potential for applications of AURORA derived products, such as tropospheric ozone and UV surface radiation, in sectors such as air quality monitoring and health.
关键词： atmospheric Sentinels,assimilation,applications,ozone profile,data synergy,fusion,ultraviolet surface radiation,Copernicus program
更新于2025-09-10 09:29:36
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Applications of Piezoelectrics: Old and New
摘要： Piezoelectric materials convert electrical energy to mechanical energy and vice versa, resulting in observed properties that are electromechanically coupled. When a piezoelectric is deformed, that mechanical energy is transformed to electrical energy, which is known as the direct piezoelectric effect. When the reverse occurs, and an electric field is applied, the material physically deforms, resulting in the converse piezoelectric effect. Therefore, piezoelectric materials can be used in both sensor and actuator applications. The magnitude of the piezoelectric response is often expressed as the longitudinal piezoelectric coefficient, d33. When measuring the direct piezoelectric effect, d33 is the polarization generated per unit of mechanical stress, where the field and stress are along the same direction. In the converse effect, d33 is the induced mechanical strain per unit of electric field applied, with the field and stress also in the same direction. Another measure of effectiveness of a piezoelectric is called the electromechanical coupling factor, k. This value expresses the efficiency of conversion from mechanical to electrical energy or vice versa.
关键词： actuator applications,electromechanical coupling factor,sensor applications,direct piezoelectric effect,Piezoelectric materials,converse piezoelectric effect
更新于2025-09-09 09:28:46
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Recent Developments Accelerating SiC Adoption
摘要： The benefits of SiC devices for use in power electronics has been long understood, and over 25 years of sustained development in materials and devices has brought adoption to a tipping point [1,15]. It takes the confluence of many separate developments to build the necessary momentum for accelerated adoption, and we will examine these factors.
关键词： SiC MOSFET,SiC reliability,SiC Schottky Diode,SiC gate oxide,SiC Cascode,Supercascode,Silicon Carbide,SiC,SiC packaging,SiC applications,SiC epitaxy,SiC substrates
更新于2025-09-09 09:28:46
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Morphological evolution of upconversion nanoparticles and their biomedical signal generation
摘要： Advancements in the fabrication of upconversion nanoparticles (UCNPs) for synthetic control can enable a broad range of applications in biomedical systems. Herein, we experimentally verified the role of the hydrothermal reaction (HR) time in the synthesis of NaYF4:20%Yb3+/3%Er3+ UCNPs on their morphological evolution and phase transformation at different temperatures. Characterizations of the as-prepared UCNPs were conducted using X-ray diffraction (XRD), electron microscopy and spectroscopy, and thermogravimetric and upconversion (UC) luminescence analysis. We demonstrated that determining the optimal HR time, also referred to here as the threshold time, can produce particles with good homogeneity, hexagonal phase, and UC luminescence efficiency. Subsequently, the polymer coated UCNPs maintained their original particle size distribution and luminescence properties, and showed improved dispersibility in a variety of solvents, cellular nontoxicity, in vitro bioimaging, and biocompatibility as compared to the bare UCNP. Besides this, polyacrylic acid conjugated UCNPs (UCNP@PAA) also revealed the strong anticancer effect by conjugating with doxorubicin (DOX) as compared to the free DOX. Based on these findings, we suggest that these particles will be useful in drug-delivery systems and as in vivo bioimaging agents synchronously.
关键词： phase transformation,morphological evolution,biomedical applications,hydrothermal reaction,upconversion nanoparticles
更新于2025-09-09 09:28:46
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Cavity losses estimation in CSP applications
摘要： Estimations of convection and radiation cavity losses in two common CSP applications have been analyzed; a cavity in a solar tower plant for high temperature (800 K) and in a down facing cavity in a Fresnel configuration for medium temperature (350 K) applications. An analysis regarding the effect of the configuration, geometry and the presence of wind has been also carried out.
关键词： solar tower plant,Fresnel configuration,convection,radiation,cavity losses,CSP applications
更新于2025-09-09 09:28:46
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A review of optical methods for continuous glucose monitoring
摘要： Frequent glucose monitoring is a fundamental part of diabetes management, and good glucose control is important for long-term health outcomes. New types of electrochemical sensors that allow for continuous glucose monitoring (CGM) have become an important tool for diabetes management, although they still have drawbacks such as short lifetime and a need for frequent calibration. Other technologies are still being researched for CGM, in an attempt to replace the electrochemical sensors. Optical methods have several advantages for CGM, including potentially long sensor lifetimes and short measurement times, and many developments have been made over the last decades. This paper will review optical measurement methods for CGM, their challenges, and the current research status. The different methods will be compared, and the future prospects for optical methods will be discussed.
关键词： Optical spectroscopy,glucose sensors,continuous glucose monitoring,quantitative optical methods,biomedical applications
更新于2025-09-09 09:28:46
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Atomic-Level Doping of Metal Clusters
摘要： Atomically precise noble metal (mainly silver and gold) nanoclusters are an emerging category of promising functional materials for future applications in energy, sensing, catalysis, and nanoelectronics. These nanoclusters are protected by ligands such as thiols, phosphines, and hydride and have sizes between those of atoms and plasmonic nanoparticles. In metallurgy, the properties of a pure metal are modified by the addition of other metals, which often offers augmented characteristics, making them more utilizable for real-life applications. In this Account, we discuss how the incorporation of various metal atoms into existing protected nanoclusters tunes their structure and properties. The process of incorporating metals into an existing cluster is known as doping; the product is known as a doped cluster, and the incorporated metal atom is called a dopant/foreign atom. We first present a brief historical overview of protected clusters and the need for doping and explain (with examples) the difference between an “alloy” and a “doped” cluster, which are two frequently confused terms. We then discuss several commonly observed challenges in the synthesis of doped clusters: (i) doping produces a mixture of compositions that prevents the growth of single crystals; (ii) doping with foreign atoms sometimes changes the overall composition and structure of the parent cluster; and (iii) doping beyond a certain number of foreign atoms decomposes the doped cluster. After delineating the challenges, we review a few potential synthetic methods for doped clusters: (i) the co-reduction method, (ii) the galvanic exchange method, (iii) ligand-induced conversion of bimetallic clusters to doped clusters, and (iv) intercluster reactions. As a foreign atom is able to occupy different positions within the structure of the parent cluster, we examine the structural relationship between the parent clusters and their different foreign-atom-doped clusters. We then show how doping enhances the stability, luminescence, and catalytic properties of clusters. The enhancement factor highly depends on the number and nature of the foreign atoms, which can also alter the charge state of the parent cluster. Atomic-level doping of foreign atoms in the parent cluster is confirmed by high-resolution electrospray ionization and matrix-assisted laser desorption ionization mass spectrometry techniques and single-crystal X-ray diffraction methods. The photophysical properties of the doped clusters are investigated using both time-dependent and steady-state luminescence and optical absorption spectroscopies. After presenting an overview of atomic-level doping in metal clusters and demonstrating its importance for enriching the chemistry and photophysics of clusters and extending their applications, we conclude this Account with a brief perspective on the field’s future.
关键词： applications,doping,properties,atomically precise,noble metal nanoclusters,alloy,synthesis,structure
更新于2025-09-09 09:28:46
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Highly Promoted Carrier Mobility and Intrinsic Stability by Rolling Up Monolayer Black Phosphorus into Nanoscrolls
摘要： Rolling up two-dimensional (2D) materials into nanoscrolls could not only retain the excellent properties of their 2D hosts, but also display intriguing physical and chemical properties that arise from their 1D tubular structures. Here, we report a new class of black phosphorus nanoscrolls (bPNSs), which are stable at room-temperature and energetically more favorable than 2D bP. Most strikingly, these bPNSs hold tunable direct band gaps and extremely high mobilities (e.g., the mobility of the double-layer bPNS is about 20-fold higher than that of 2D bP monolayer). Their unique self-encapsulation structure and layer-dependent conduction band minimum can largely prevent the entering of O2 and the production of O?2 and thereby suppress the possible environmental degradation as well. The enhanced intrinsic stability and promoted electronic properties render bPNSs great promise in many advanced electronics or optoelectronics applications.
关键词： optoelectronic applications,black phosphorus nanoscrolls,carrier mobility,intrinsic stability,electronic properties
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE International Symposium on Medical Measurements and Applications (MeMeA) - Rome, Italy (2018.6.11-2018.6.13)] 2018 IEEE International Symposium on Medical Measurements and Applications (MeMeA) - Feasibility of Photoplethysmography Imaging of the Sole of the Foot
摘要： In photoplethysmography imaging the blood volume pulse is extracted from subtle skin color variations recorded with a camera. In most works, the camera is oriented towards the face or the palm of the hand. Recently, it has been shown that applying contact force to the skin, e.g. through contact with a glass plate, increases signal strength. However, this approach is prohibitive for the face and there are applications where the hands are not accessible. In this paper, we address this issue by applying photoplethysmography imaging to the sole of the foot, which is placed on a glass plate and exposed to controlled illumination. We investigate (1) whether this setup acquires signals with an adequate signal-to-noise ratio and (2) whether the feet can be used as a replacement for the more commonly used hands. Additionally, we analyze (3) whether using a carefully selected pixel subset instead of all pixels improves signal-to-noise ratio. We report on experimental data from N=21 healthy subjects that we make publicly available1. We applied photoplethysmography imaging to the sole of the foot and the palm of the hand and used a commercial ?nger photoplethysmography unit as ground truth. It is problematic that there is no established best practice for signal-to-noise estimation in PPGi research; hence we use ?ve different metrics with three from literature. Additionally, we compare the agreement of these metrics using the experimental data. Our results show that (1) the proposed setup acquires signals with an adequate signal-to-noise ratio, (2) using all pixels from foot videos results in slightly inferior performance compared to the hand, but (3) using pixel subsets improves signal quality at the foot to the level of the hand. These results pave the way for the development of a photoplethysmography imaging setup applied at the sole of the foot for different medical applications.
关键词： photoplethysmography imaging,blood volume pulse,signal-to-noise ratio,medical applications,pixel subset
更新于2025-09-09 09:28:46
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Future prospects of fluoride based upconversion nanoparticles for emerging applications in biomedical and energy harvesting
摘要： Rare earth doped/codoped phosphors have been extensively studied for different types of applications based on their intense luminescence features. For this, researchers have tried to choose the inorganic host matrices having both a low phonon cut-off frequency and a high refractive index. Many articles have been published on oxide based phosphor materials, but due to their high cut-off phonon frequency, use of these materials is restricted for optical based applications. This is why additional research has been carried out on fluoride based host materials because of their low phonon frequencies, low composition degradation, and high quantum efficiency. In this paper, the authors review the rare earth fluoride based host nano- and micromaterials for different applications and discuss possible mechanisms.
关键词： biomedical applications,fluoride based upconversion nanoparticles,energy harvesting,luminescence,rare earth doped phosphors
更新于2025-09-09 09:28:46