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norskBlar i tittel Artikler, rapporter og annet (fysikk og teknologi)
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On the secondary charging effects and structure of mesospheric dust particles impacting on rocket probes
(Journal article; Tidsskriftartikkel; Peer reviewed, 2007) -
On the strength of E and F region irregularities for GNSS scintillation in the dayside polar ionosphere
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-02)We present results of the study conducted to quantify the relative contribution of different ionospheric regions to phase scintillation in Global Navigation Satellite Systems (GNSS) at the dayside high latitude ionosphere. By taking advantage of the scanning capability of the 32-m EISCAT radar in Svalbard (ESR) and its recurrent favourable location below the dayside auroral region, we developed ... -
On the symmetry of ionospheric polar cap patch exits around magnetic midnight
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-07-14)In this paper we examine how polar cap patches, which have been frozen into the antisolar flow over the polar cap, are transported into the nighttime auroral oval. First we present a detailed case study from 12 January 2002, with continuous observations of polar cap patches exiting into the nighttime auroral oval in the Scandinavian sector. Satellite images of the auroral oval and all-sky camera ... -
On the theory of the incoherent scatter gyrolines
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07-20)The incoherent scatter spectrum feature referred to as the “gyroline” is investigated theoretically and experimentally. The gyroline is associated with the dispersion relation for electrostatic whistler waves. Earlier treatments by Trulsen and Bj⊘rna (1978, and references therein) derive the frequency and growth rate for these waves, but their derivation is only accurate for very small magnetic ... -
On the wake structure in streaming complex plasma
(Journal article; Tidsskriftartikkel; Peer reviewed, 2012)The theoretical description of complex (dusty) plasmas requires multiscale concepts that adequately incorporate the correlated interplay of streaming electrons and ions, neutrals and dust grains. Knowing the effective dust–dust interaction, the multiscale problem can be effectively reduced to a one-component plasma model of the dust subsystem. The goal of this paper is a systematic evaluation of the ... -
On-chip TIRF nanoscopy by applying Haar wavelet kernel analysis on intensity fluctuations induced by chip illumination
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-09)Photonic-chip based TIRF illumination has been used to demonstrate several on-chip optical nanoscopy methods. The sample is illuminated by the evanescent field generated by the electromagnetic wave modes guided inside the optical waveguide. In addition to the photokinetics of the fluorophores, the waveguide modes can be further exploited for introducing controlled intensity fluctuations for exploitation ... -
On-Site Ribosome Remodeling by Locally Synthesized Ribosomal Proteins in Axons
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-12-10)Ribosome assembly occurs mainly in the nucleolus, yet recent studies have revealed robust enrichment and translation of mRNAs encoding many ribosomal proteins (RPs) in axons, far away from neuronal cell bodies. Here, we report a physical and functional interaction between locally synthesized RPs and ribosomes in the axon. We show that axonal RP translation is regulated through a sequence motif, ... -
One-Year Analysis of Dust Impact-Like Events Onto the MMS Spacecraft
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-16)We present an analysis of 1‐year data of dust impacts observed on two of the Earth‐orbiting Magnetospheric Multiscale mission (MMS) spacecraft. The dust impact signals were identified in observations of the electric field probes and were registered simultaneously by monopole and dipole configurations of the instrument. This unique setup allows us to reliably identify changes in the spacecraft potential ... -
OpenMetBuoy-v2021: An Easy-to-Build, Affordable, Customizable, Open-Source Instrument for Oceanographic Measurements of Drift and Waves in Sea Ice and the Open Ocean
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-02-26)There is a wide consensus within the polar science, meteorology, and oceanography communities that more in situ observations of the ocean, atmosphere, and sea ice are required to further improve operational forecasting model skills. Traditionally, the volume of such measurements has been limited by the high cost of commercially available instruments. An increasingly attractive solution to this ... -
The optical afterglow and host galaxy of GRB 000926
(Journal article; Tidsskriftartikkel, 2001-04-11)We present the discovery of the Optical Transient (OT) of the long–duration gamma-ray burst GRB 000926. The optical transient was detected independently with the Nordic Optical Telescope and at Calar Alto 22.2 hours after the burst. At this time the magnitude of the transient was R = 19.36. The transient faded with a decay slope of about 1.7 during the first two days after which the slope increased ... -
Optical transport, lifting and trapping of micro-particles by planar waveguides
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-03-03)Optical waveguides can be used to trap and transport micro-particles. The particles are held close to the waveguide surface by the evanescent field and propelled forward. We propose a new technique to lift and trap particles above the surface of the waveguides. This is made possible by a gap between two opposing, planar waveguides. The field emitted from each of the waveguide ends diverge fast, away ... -
Optical trapping and propulsion of red blood cells on waveguide surfaces
(Journal article; Tidsskriftartikkel; Peer reviewed, 2010) -
Optical trapping in air on a single interference fringe
(Journal article; Tidsskriftartikkel, 2023)Stable and reproducible trapping in air of 1 µm and 500 nm dielectric particles has been realized using a dual beam optical fiber tweezers with cleaved commercial single mode fibers. The influence of the interference fringes of the two coherent and counter-propagating trapping beam is investigated by controlling the fringe visibility. Optical trapping on a series of upto10 fringes or trapping on ... -
OptiJ: Open-source optical projection tomography of large organ samples
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-30)The three-dimensional imaging of mesoscopic samples with Optical Projection Tomography (OPT) has become a powerful tool for biomedical phenotyping studies. OPT uses visible light to visualize the 3D morphology of large transparent samples. To enable a wider application of OPT, we present OptiJ, a low-cost, fully open-source OPT system capable of imaging large transparent specimens up to 13 mm tall ... -
An Optimal Decision-Tree Design Strategy and Its Application to Sea Ice Classification from SAR Imagery
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-03)We introduce the fully automatic design of a numerically optimized decision-tree algorithm and demonstrate its application to sea ice classification from SAR data. In the decision tree, an initial multi-class classification problem is split up into a sequence of binary problems. Each branch of the tree separates one single class from all other remaining classes, using a class-specific selected feature ... -
Organization of the magnetosphere during substorms
(Journal article; Tidsskriftartikkel; Peer reviewed, 2012)The change in degree of organization of the magnetosphere during substorms is investigated by analyzing various geomagnetic indices, as well as interplanetary magnetic field z-component and solar wind velocity x-component. We conclude that the magnetosphere self-organizes globally during substorms, but neither the magnetosphere nor the solar wind become more predictable in the course of a substorm. ... -
Oscillations:Linear theory and applications in AFM
(Research report; Forskningsrapport, 2022)The theory of oscillations can be studied from a mathematical point of view in terms of differential equations. The differential equation is written and then the solution or solutions worked out and mathematically analysed. Provided physical, economic, social, or other phenomena can be modelled in terms of equivalent differential equations, the solutions and results are applicable to all phenomena ... -
Outlier classification using autoencoders: Application for fluctuation driven flows in fusion plasmas
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-16)Understanding the statistics of fluctuation driven flows in the boundary layer of magnetically confined plasmas is desired to accurately model the lifetime of the vacuum vessel components. Mirror Langmuir probes (MLPs) are a novel diagnostic that uniquely allow us to sample the plasma parameters on a time scale shorter than the characteristic time scale of their fluctuations. Sudden large-amplitude ... -
Outlier classification using Autoencoders: applications for fluctuation driven flows in fusion plasmas
(Conference object; Konferansebidrag, 2018) -
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 ...
