Search results for "RADIATION"
showing 10 items of 5298 documents
Deep traps in InGaN/GaN single quantum well structures grown with and without InGaN underlayers
2020
The electrical properties and deep trap spectra were compared for near-UV GaN/InGaN quantum well (QW) structures grown on free-standing GaN substrates. The structures differed by the presence or absence of a thin (110 nm) InGaN layer inserted between the high temperature GaN buffer and the QW region. Capacitance-voltage profiling with monochromatic illumination showed that in the InGaN underlayer (UL), the density of deep traps with optical threshold near 1.5 eV was much higher than in the QW and higher than for structures without InGaN. Irradiation with 5 MeV electrons strongly increased the concentration of these 1.5 eV traps in the QWs, with the increase more pronounced for samples witho…
Effects of InAlN underlayer on deep traps detected in near-UV InGaN/GaN single quantum well light-emitting diodes
2019
Two types of near-UV light-emitting diodes (LEDs) with an InGaN/GaN single quantum well (QW) differing only in the presence or absence of an underlayer (UL) consisting of an InAlN/GaN superlattice (SL) were examined. The InAlN-based ULs were previously shown to dramatically improve internal quantum efficiency of near-UV LEDs, via a decrease in the density of deep traps responsible for nonradiative recombination in the QW region. The main differences between samples with and without UL were (a) a higher compensation of Mg acceptors in the p-GaN:Mg contact layer of the sample without UL, which correlates with the presence of traps with an activation energy of 0.06 eV in the QW region, (b) the…
Fluence rate or cumulative dose? : Vulnerability of larval northern pike (Esox lucius) to ultraviolet radiation
2007
Newly hatched larvae of northern pike were exposed in the laboratory to four fluence rates of ultraviolet radiation (UVR; 290–400 nm) over three different time periods, resulting in total doses ranging from 3.0 ± 0.2 to 63.0 ± 4.4 kJ·m−2. Mortality and behavior of the larvae were followed for 8–12 days, and growth measured at the end of the experiment. Also, the principle of reciprocity—that the UVR-induced mortality depends on the cumulative dose, independent of fluence rate—was tested. Fluence rates higher than 1480 ± 150 mW·m−2 caused mortality and growth retardation. The highest fluence rate (3040 ± 210 mW·m−2) caused 100% mortality in 5 days. All fluence rates caused behavioral disorde…
Generation of homozygosity and genome fixation in pea (Pisum sativum L.)
2013
Pea cultivars are nearly homozygous and thus homogeneous when they are released. The traditional method of selfing is slow and inefficient, taking up to ten generations of inbreeding following a cross to achieve a high level of homozygosity. Current single-seed-descent (SSD) methodologies enable a maximum of three generations per year to be developed in pea. Doubled haploidy and an in vitro based modified SSD technology have been utilised in many important crops for the rapid achievement of homozygosity, and thus acceleration of the breeding process. In pea, due to the lack of robust protocols, none of these technologies is routinely used in a breeding program. The aim of this study was to …
Electromagnetic wave propagation in non-homogeneous waveguides
2015
We investigate an electromagnetic waveguide, having several cylindrical ends. The waveguide is assumed to be empty and to have a perfectly conductive boundary. We study the electromagnetic field, excited in the waveguide in the presence of charges and currents. The field can be described as a solution of the stationary Maxwell system with conductive boundary conditions and “intrinsic” radiation conditions at infinity. We prove the problem to be well-posed. Electromagnetic waves propagation in the waveguide can be described by means of a scattering matrix. We introduce such a matrix for all values of the spectral parameter k in the waveguide continuous spectrum and study its properties. Moreove…
Biochar from Waste Derived Fuels as Low-Cost Adsorbent for Waste Hydrocarbons
2020
Abstract The aim of this study is to prove technical feasibility of combined refuse derived fuel (RDF) torrefaction and oily wastewater treatment approach by using RDF derived biochar as a sorption media. Biochars prepared from refuse derived fuels in torrefaction, carbonization and pyrolysis modes were analysed as fuels and as hydrocarbon sorbents. Changes of elemental composition and properties of material during thermal treatment and subsequent washing process have been analysed. Experimental evaluation of sorption behaviour of toluene and diesel fuel on obtained biochar performed. Our results show that torrefaction/carbonization of RDF coupled with the subsequent washing of biochar is a…
End-of-Life Care in High-Grade Glioma Patients. The Palliative and Supportive Perspective.
2018
High-grade gliomas (HGGs) are the most frequently diagnosed primary brain tumors. Even though it has been demonstrated that combined surgical therapy, chemotherapy, and radiotherapy improve survival, HGGs still harbor a very poor prognosis and limited overall survival. Differently from other types of primary neoplasm, HGG manifests also as a neurological disease. According to this, palliative care of HGG patients represents a peculiar challenge for healthcare providers and caregivers since it has to be directed to both general and neurological cancer symptoms. In this way, the end-of-life (EOL) phase of HGG patients appears to be like a journey through medical issues, progressive neurologic…
Human interleukin-6 facilitates hepatitis B virus infection in vitro and in vivo.
2000
Abstract Background and aim. Research on hepatitis B virus (HBV) infection in vivo has been limited due to the absence of a suitable animal model. We have developed a human–mouse radiation chimera in which normal mice, preconditioned by lethal total body irradiation and radioprotected with SCID mouse bone marrow cells, are permissive for engraftment of human hematopoietic cells and solid tissues. This resulting human–mouse model, which comprises three genetically disparate sources of tissue, is therefore termed Trimera. This study was aimed at assessing the effect of human IL-6 on HBV infection in vivo in Trimera mice. Methods. Trimera mice were transplanted with human liver tissue fragment…
Technical and economic aspects of photovoltaic conversion of southern Poland
2014
W artykule przedstawiono wyniki 13-letniej analizy testowania sprawności oraz uzysku energii i ładunku elektrycznego typowych modułów fotowoltaicznych wykonanych z różnych absorberów, zainstalowanych na południowej ścianie budynku Uniwersytetu Opolskiego przy ulicy kard. B. Kominka. Zarejestrowane w tym okresie (2001-2013) wartości kumulacji energii i ładunku testowanych modułów przedstawiono zarówno w odniesieniu do 1 Wp ich mocy nominalnej, jak i do 1 m2 powierzchni modułów PV. Przedstawiono ich roczne i miesięczne rozkłady ze szczególnym uwzględnieniem sezonowości zmian ich parametrów oraz zjawiska starzenia i degradacji struktury modułów PV. W końcowej części artykułu zaprezentowano eko…
Trade-off Performance of Optical Nanoantennas for Solar Energy Harvesting Applications
2019
In this paper, the optimum behaviour of optical nanoantennas, in terms of impedance, directivity, available power, and field enhancement, at a resonance frequency of about 350 THz, will be shown. Optimum configurations are obtained by varying nanoantennas geometry in order to maximize the available power, enhancing the electric field in gap proximity and so the absorptivity. Moreover, the simulation results for aluminum nanoantennas on a three-layers substrate, will be reported, and a trade-off performance comparison among different antennas will be discussed. This study can guide both the engineering and the fabrication of plasmonic nanoantennas.