Artikler, rapporter og annet (fysikk og teknologi): Nye registreringer
Viser treff 341-360 av 1057
-
Springtime nitrogen oxides and tropospheric ozone in Svalbard: results from the measurement station network
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-09)Svalbard is a remote and scarcely populated Arctic archipelago and is considered to be mostly influenced by long-range-transported air pollution. However, there are also local emission sources such as coal and diesel power plants, snowmobiles and ships, but their influence on the background concentrations of trace gases has not been thoroughly assessed. This study is based on data of tropospheric ... -
Rapid Colorimetric pH-Responsive Gold Nanocomposite Hydrogels for Sensing Applications
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-04-27)Surface functionalization of metallic nanoparticles (NPs) with external groups can be engineered to fabricate sensors that are responsive to various stimuli like temperature, pH, and numerous ions. Herein, we report the synthesis of gold nanoparticles (GNPs) functionalized with 3-mercaptopropionic acid (GNPs-MPA) and the doping of these nanoparticles into hydrogel materials using the ... -
Significant ionospheric hole and equatorial plasma bubbles after the 2022 Tonga volcano eruption
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-28)This paper investigates the local and global ionospheric responses to the 2022 Tonga volcano eruption, using ground-based Global Navigation Satellite System total electron content (TEC), Swarm in situ plasma density measurements, the Ionospheric Connection Explorer (ICON) Ion Velocity Meter (IVM) data, and ionosonde measurements. The main results are as follows: (a) A significant local ionospheric ... -
Imaging the Effects of Whole-Body Vibration on the Progression of Hepatic Steatosis by Quantitative Ultrasound Based on Backscatter Envelope Statistics
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-29)Hepatic steatosis causes nonalcoholic fatty liver disease. Whole-body vibration (WBV) has been recommended to allow patients who have difficulty engaging in exercise to improve the grade of hepatic steatosis. This study proposed using ultrasound parametric imaging of the homodyned K (HK) distribution to evaluate the effectiveness of WBV treatments in alleviating hepatic steatosis. Sixty mice were ... -
Multiple E-Region Radar Propagation Modes Measured by the VHF SIMONe Norway System During Active Ionospheric Conditions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-10)Multiple propagation modes between different bistatic radar links were measured during the operations of a very high frequency (VHF) 32.55 MHz radar system in northern Norway. The Spread Spectrum Interferometric Multistatic meteor radar Observing Network (SIMONe) Norway system detected meteor trails, direct transmitter to receiver signal propagation, over-the-horizon signal propagation from the ... -
On the determination of ionospheric electron density profiles using multi-frequency riometry
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-27)Radio wave absorption in the ionosphere is a function of electron density, collision frequency, radio wave polarisation, magnetic field and radio wave frequency. Several studies have used multi-frequency measurements of cosmic radio noise absorption to determine electron density profiles. Using the framework of statistical inverse problems, we investigated if an electron density altitude profile ... -
Performance Analysis of Roll-Invariant PolSAR Parameters from C-band images with Regard to Sea Ice Type Separation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06)The Polarimetric Synthetic Aperture Radar (PolSAR) backscatter from a target is dependent on the incidence angle. Consequently, the associated roll invariant parameters are affected by changes in incidence angle. In this work, we identify a few of these parameters that remain robust in identifying sea ice features even under large incidence angle variations. We conclude that the helicity angle ... -
An alternative approach for calculating the SAR damping ratio of verified oil slicks
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022)The damping ratio is a calculated feature that measures the contrast between oil-slicked water and the open ocean in SAR data. To implement the damping ratio, the current literature suggests estimating the open water backscatter by taking strips of undefined width across the range direction, obtaining the damping ratio as a function of incidence angle. We show in this paper that the method proposed ... -
Horizontal Wavenumber Spectra of Vertical Vorticity and Horizontal Divergence of Mesoscale Dynamics in the Mesosphere and Lower Thermosphere Using Multistatic Specular Meteor Radar Observations
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-24)Specular meteor radars (SMRs) have significantly contributed to the understanding of wind dynamics in the mesosphere and lower thermosphere (MLT). We present a method to estimate horizontal correlations of vertical vorticity (Qzz) and horizontal divergence (P) in the MLT, using line-of-sight multistatic SMRs velocities, that consists of three steps. First, we estimate 2D, zonal, and meridional ... -
Chip-based multimodal super-resolution microscopy for histological investigations of cryopreserved tissue sections
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-02-24)Histology involves the observation of structural features in tissues using a microscope. While diffraction-limited optical microscopes are commonly used in histological investigations, their resolving capabilities are insufficient to visualize details at subcellular level. Although a novel set of super-resolution optical microscopy techniques can fulfill the resolution demands in such cases, the ... -
Towards robust partially supervised multi-structure medical image segmentation on small-scale data
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-20)The data-driven nature of deep learning (DL) models for semantic segmentation requires a large number of pixel-level annotations. However, large-scale and fully labeled medical datasets are often unavailable for practical tasks. Recently, partially supervised methods have been proposed to utilize images with incomplete labels in the medical domain. To bridge the methodological gaps in ... -
Frequency spectra of horizontal winds in the mesosphere and lower thermosphere region from multistatic specular meteor radar observations during the SIMONe 2018 campaign
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-11)In recent years, multistatic specular meteor radars (SMRs) have been introduced to study the Mesosphere and Lower Thermosphere (MLT) dynamics with increasing spatial and temporal resolution. SMRs, compared to other groundbased observations, have the advantage of continuously measuring the region between 80 and 100 km independent of weather, season, or time of day. In this paper, frequency spectra ... -
Multi-moded high-index contrast optical waveguide for super-contrast high-resolution label-free microscopy
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-20)The article elucidates the physical mechanism behind the generation of superior-contrast and highresolution label-free images using an optical waveguide. Imaging is realized by employing a high index contrast multi-moded waveguide as a partially coherent light source. The modes provide near-field illumination of unlabeled samples, thereby repositioning the higher spatial frequencies of the ... -
Effects of particle precipitation on the polar mesospheric summer echoes observed by EISCAT VHF 224 MHz radar
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-02-23)We present the results from investigation of spectra of polar mesospheric summer echoes (PMSE) observed with EISCAT VHF 224 MHz radar during energetic particle precipitation events in the summer of 2019. We used the sudden enhancements in electron densities derived from the VHF observations above 90 km as indicators of particle precipitation. We find that the altitude extent of the PMSE increased ... -
A Stimulated Emission Diagnostic Technique for Electron Temperature of the High Power Radio Wave Modified Ionosphere
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-09)We report observations of stimulated electromagnetic emission (SEE) induced by high power high frequency (HF) radio waves near the third electron gyroharmonic (3urn:x-wiley:00948276:media:grl64672:grl64672-math-0022) at European Incoherent Scatter Radar (EISCAT). It is discovered that stimulated Brillouin scattering (SBS) spectrum behaves similarly as spectral ion lines of the incoherent scatter ... -
A 30-year probability map for oil spill trajectories in the barents sea to assess potential environmental and socio-economic threats
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-24)Increasing exploration and exploitation activity in the Arctic Ocean has intensified maritime traffic in the Barents Sea. Due to the sparse population and insufficient oil spill response infrastructure on the extensive Barents Sea shoreline, it is necessary to address the possibility of offshore accidents and study hazards to the local environment and its resources. Simulations of surface oil ... -
Unbalanced low coherence interference microscopy
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-03)Low coherence interference microscopy (LCIM) provides high spatial phase sensitivity, i.e., speckle free and coherent noise free quantitative phase images of the test specimens. Due to low temporal coherence (TC) length of the light source, LCIM requires precise adjustment of the optical path difference (OPD) between the object and the reference arm, which is only a few micrometers. Consequently, ... -
Overview: Recent advances in the understanding of the northern Eurasian environments and of the urban air quality in China-a Pan-Eurasian Experiment (PEEX) programme perspective
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-04-06)The Pan-Eurasian Experiment (PEEX) Science Plan, released in 2015, addressed a need for a holistic system understanding and outlined the most urgent research needs for the rapidly changing Arctic-boreal region. Air quality in China, together with the long-range transport of atmospheric pollutants, was also indicated as one of the most crucial topics of the research agenda. These two geographical ... -
Rechargeable Iron-Ion Battery Using a Pure Ionic Liquid Electrolyte
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-07)A rechargeable iron-ion battery (Fe-ion battery) has been fabricated in our laboratory using a pure ionic liquid electrolyte. Magnetic ionic liquids of 1-butyl-3-methylimidazolium tetrachloroferrate (BmimFeCl<sub>4</sub>) and 1-methyl-3-octylimidazolium tetrachloroferrate (OmimFeCl<sub>4</sub>) are synthesized and utilized as electrolytes in this work. The chemical structure of the two ionic ... -
Three-dimensional structured illumination microscopy data of mitochondria and lysosomes in cardiomyoblasts under normal and galactose-adapted conditions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-23)This three-dimensional structured illumination microscopy (3DSIM) dataset was generated to highlight the suitability of 3DSIM to investigate mitochondria-derived vesicles (MDVs) in H9c2 cardiomyoblasts in living or fxed cells. MDVs act as a mitochondria quality control mechanism. The cells were stably expressing the tandem-tag eGFP-mCherry-OMP25-TM (outer mitochondrial membrane) which can be used ...