Search results for "optical"
showing 10 items of 7671 documents
Field effect in the viscosity of magnetic colloids studied by multi-particle collision dynamics
2019
Abstract Colloidal solutions of magnetic nanoparticles are usually employed when the fluidity and magnetic properties are required at the same time, either in technical or biomedical applications. However, when the magnetic size of the nanoparticles is large enough (>12–15 nm) the colloid may form an equilibrium structure with or without the external magnetic field, which can significantly influence its rheology. Using multi-particle collision dynamics we study the internal structure and viscosity of the magnetic colloids at varying magnitudes of the externally applied field. We show a generalized structural behavior across all studied regimes and an appreciable increase of flow resistance …
High-frequency electrodeless lamps in argon–mercury mixtures
2005
In this paper, numerical and experimental investigations of high-frequency (HF) electrodeless lamps in argon–mercury mixtures are performed. The intensities of the mercury spectral lines having wavelengths λ = 404.66, 435.83, 546.07 nm (7 3S1–6 3P0,1,2) and the resonance line λ = 253.7 nm (6 3 P1–6 1S0) are measured at a wide range of mercury pressures, varying the HF generator current and argon filling pressure. A stationary self-consistent model of HF electrodeless discharge lamp is developed including kinetics of the excited mercury and argon atomic states. Based on the developed model, the radiation characteristics of the discharge plasma are calculated. Numerical simulation of the line…
IEEE Magnetics Society Distinguished Lecturers for 2020
2019
With information technology consuming a sizeable part of the total energy, “Green IT” information storage and computing technology will have a major impact on addressing societal challenges.
Space charge behavior of different insulating materials employed in AC and DC cable systems
2017
In this work, the space charge accumulation in three different XLPE based material has been carried out by using the PEA (Pulsed Electro-Acoustic) method. The specimens provided by a cables industry have been subjected to the same DC stress during polarization time at environment temperature. Afterwards, the high voltage generator has been turned off and the amount residual charge has been evaluated. The space charge profiles during polarization and depolarization have been carried out and compared. Finally, the distribution of electric field within the samples has been reported. In particular, the maximum distortion of electric field has been calculated by taking into account the distribut…
Computational volumetric reconstruction of integral imaging with improved depth resolution considering continuously non-uniform shifting pixels
2018
Abstract In this paper, we propose a new computational volumetric reconstruction technique of three-dimensional (3D) integral imaging for depth resolution enhancement by using non-uniform and integer-valued shifting pixels. In a typical integral imaging system, 3D images can be recorded and visualized using a lenslet array. In previous studies, many computational reconstruction techniques such as computational volumetric reconstruction and pixel of elemental images rearrangement technique (PERT) have been reported. However, a computational volumetric reconstruction technique has low visual quality and depth resolution because low-resolution elemental images and uniformly distributed shiftin…
Silicon Surface Passivation by ALD-Ga2O3: Thermal vs. Plasma-Enhanced Atomic Layer Deposition
2020
Silicon surface passivation by gallium oxide (Ga2O3) thin films deposited by thermal- and plasma-enhanced atomic layer deposition (ALD) over a broad temperature range from 75 °C to 350 °C is investigated. In addition, the role of oxidant (O3 or O-plasma) pulse lengths insufficient for saturated ALD-growth is studied. The material properties are analyzed including the quantification of the incorporated hydrogen. We find that oxidant dose pulses insufficient for saturation provide for both ALD methods generally better surface passivation. Furthermore, different Si surface pretreatments are compared (HF-last, chemically grown oxide, and thermal tunnel oxide). In contrast to previous reports, t…
Object size effect on the contact potential difference measured by scanning Kelvin probe method
2010
International audience; Contact potential difference (CPD) was measured by macroscopic Kelvin probe instrument and scanning Kelvin probe microscope on Al, Ni and Pt on ITO substrates at ambient conditions. CPD values measured by scanning Kelvin probe microscope and macroscopic Kelvin probe are close within the error of about 10-30% for large studied objects, whereas scanning Kelvin probe microscope signal decreases, when the object size becomes smaller than 1.4 m. CPD and electric field signals measured using many-pass technique allowed us to estimate the influence of electrostatic field disturbance, especially, in the case of small objects.
New fine structures resolved at the ELNES Ti-L2,3 edge spectra of anatase and rutile: comparison between experiment and calculation.
2010
Abstract Anatase and rutile Ti- L 2,3 edge spectra were measured in electron energy loss spectroscopy (EELS) using a transmission electron microscope (TEM) coupled to a CEOS Cs-probe corrector, an omega-type monochromator and an in-column omega-type energy filter fully corrected for 2nd order aberrations. Thanks to the high energy resolution, high electron probe current and high stability achieved under this instrumental configuration, new fine structures, never reported before, were resolved at the L 3 band of both rutile and anatase. The data suggest that new peaks also exist in the L 2 e g band. The experimental spectra are compared with multichannel multiple scattering (MMS) calculation…
Exploring the transport properties of equatorially low coordinated erbium single ion magnets
2019
Single-molecule spin transport represents the lower limit of miniaturization of spintronic devices. These experiments, although extremely challenging, are key to understand the magneto-electronic properties of a molecule in a junction. In this context, theoretical screening of new magnetic molecules provides invaluable knowledge before carrying out sophisticated experiments. Herein, we investigate the transport properties of three equatorially low-coordinated erbium single ion magnets with C3v symmetry: Er[N(SiMe3)2]3 (1), Er(btmsm)3 (2) and Er(dbpc)3 (3), where btmsm=bis(trimethylsilyl)methyl and dbpc=2,6-di-tert-butyl-p-cresolate. Our ligand field analysis, based on previous spectros…
Ab initio calculations of CaZrO3, BaZrO3, PbTiO3 and SrTiO3 (001), (011) and (111) surfaces as well as their (001) interfaces
2019
We carried out ab initio calculations for technologically important ABO3 perovskites, like, CaZrO3, BaZrO3, PbTiO3 and SrTiO3, their (001), (011) and (111) surfaces as well as (001) interfaces. For...