86 research outputs found
Electron supersurface scattering on polycrystalline Au
Supersurface electron scattering, i.e., electron energy losses and associated deflections in vacuum above the surface of a medium, is shown to contribute significantly to electron spectra. We have obtained experimental verification (in absolute units) of theoretical predictions that the angular distribution of the supersurface backscattering probability exhibits strong oscillations which are anticorrelated with the generalized Ramsauer-Townsend minima in the backscattering probability. We have investigated 500-eV electron backscattering from an Au surface for an incidence angle of 70° and scattering angles between 37° and 165°. After removing the contribution of supersurface scattering from the experimental data, the resulting angular and energy distribution agrees with the Landau-Goudsmit-Saunderson (LGS) theory, which was proposed about 60 years ago, while the raw data are anticorrelated with LGS theory. This result implies that supersurface scattering is an essential phenomenon for quantitative understanding of electron spectra
A Scenedesmus quadricauda zöldalga faj élő és holt biomasszájának cink akkumulációs sajátságai
Az emberi tevĂ©kenysĂ©g következtĂ©ben a környezetszennyezĂ©s napjainkban globális mĂ©reteket ölt, amely közvetlenĂĽl a bioszfĂ©ra elemeit (vĂz, talaj, levegĹ‘) Ă©s közvetve az Ă©lĹ‘ szervezeteket veszĂ©lyezteti. A környezetbe kikerĂĽlĹ‘ kĂ©miai anyagok közĂĽl egĂ©szsĂ©gĂĽgyi, biolĂłgiai Ă©s ökolĂłgiai szempontbĂłl a legveszĂ©lyesebb szennyezĹ‘anyagok közĂ© tartoznak a nehĂ©zfĂ©mek.
A Scenedesmus fajok, köztĂĽk a S. quadricauda szĂ©les körben elterjedt, gyakori zöldalga fajok, laboratĂłriumban viszonylag egyszerűen fenntarthatĂłk, gyorsan szaporĂthatĂłk, amely szĂ©leskörű biotechnolĂłgiai alkalmazásokra ad lehetĹ‘sĂ©get. A Scenedesmus quadricauda a cinket mg/L nagyságrendben elviselni kĂ©pes fajok közĂ© tartozik, eredmĂ©nyeink alapján azonban az alacsonyabb tűrĹ‘kĂ©pessĂ©gűek közĂ© sorolhatĂł. A növekvĹ‘ cinkkoncentráciĂłval (2,5 mg/L – 15 mg/L) csökken a növekedĂ©s intenzitása. A megkötött cink mennyisĂ©ge az 5 mg/L cinkkel kezelt tenyĂ©szetben a tenyĂ©sztĂ©si idĹ‘ 7. napján volt a legmagasabb (a bevitt cinkmennyisĂ©g 87,6 %-a) Ă©s a megkötött cink nagyobb rĂ©sze (77-89%-a) extracellulárisan kötĹ‘dött meg. A holt biomassza cink megkötĂ©se is jelentĹ‘s volt, de az Ă©lĹ‘ sejtek cink megkötĂ©sĂ©hez kĂ©pest szignifikánsan kevesebb volt a megkötött cink mennyisĂ©ge (a bemĂ©rt cinkmennyisĂ©g 56-58%-a kötĹ‘dött meg)
Non-conventional geoelectric arrays : practical results of the OTKA project K49604
In this paper we provide a comprehensive summary about the practical results
of the OTKA project K49604. 1. We calculated the consequences of incorrect positioning
of the electrodes for various multielectrode systems. In practice these effects
were found to be negligible. The only exception is the case of rocky surface, where it
is impossible to put the electrodes in the desired positions. The errors can however
be kept within an acceptable range, if the electrodes of the linear arrays are put
off-set, at right angles from the measuring line. A five-six times larger off-set has less
effect than a certain mis-position along the line, connecting the electrodes. 2. We
carried out tensorial geoelectric measurements around the Cistercian Monastery at
Pilisszentkereszt. Areal measurements provide much more detailed and unambiguous
anomalies than 2D profile measurements, and the tensor invariant representation of
apparent resistivity anomalies provides a realistic picture about the lateral variation
of the subsurface resistivity, even in field circumstances. 3. We tested the applicability
of 3D electrical resistivity tomography (ERT) technique to detect landmines
in different soil conditions and at various depths. Metallic and non-metallic landmines
buried in wet and dry soils had been synthetically modeled. According to the
inverted resistivity data using the dipole axial array in wet environment, it was possible
to locate the metallic and non-metallic landmines as long as the noise level was
about 5%. 4. We elaborated moreover a geoelectrical procedure which is able to map
multidirectional fissure systems by combining geoelectrical profiling and geoelectrical
azimuthal measurements. Results received by using both the so-called null-, and
traditional arrays were jointly interpreted. The humidity of the fissures affects the
measured results significantly, and in a meaningful way. 5. We presented the socalled
standardized pricking probe (PP) surveying technique and demonstrated its
usefulness in an archaeological study. The PP images proved to be definitely more
close to the realistic shape of the buried chapel than the geoelectric and magnetic
measurements, and they also revealed more details about the subsurface than the
georadar. The optimum PP parameters: horizontal interval, pricking depth, observable
quantity and its way of presentation were optimized through field experiments.
For more details see the cited publications. The figures ever published in Hungarian
journals are not reproduced here.
Keywords: 3D ERT; geometric nois
Gimnáziumi és szakgimnáziumi tanulók idegennyelv-tanulási eredményessége
Developing the foreign language skills of the Hungarian youth has been in the limelight of the Hungarian education policy in the last two decades. However, results show considerable differences among students in foreign language learning effectiveness. Research studies have explained the discrepancy by differences in motivation, sense of languages, learning strategies, attitude and family background. This study aims to investigate the effect of social background on effectiveness. We analysed the language skills of secondary grammar and secondary technical school students from objective and subjective perspectives, examined the factors behind success and analyzed the out-of-school activities and actors supporting foreign language learning. We hypothesized that secondary grammar school students were more effective language learners than secondary technical school students, the number of foreign language lessons did not affect effectiveness and children with higher-educated parents were more successful language learners.
Our survey-based pilot study was conducted among 105 secondary school students (9-12 graders from 4 grammar and 3 technical schools) at the turn of 2018/19. Although 34% had a language certificate, based on self-assessment, significantly more students declared having intermediate or advanced foreign language skills. Successful language exams and good speaking skills generated the feeling of success while the feeling of failure was due to the lack of language exams. Our results showed that successful language learning correlated with the parental level of education and the students’ perception of the importance of language skills, but did not correlate with the number of foreign language lessons in school. Students’ language exam plans were motivated by the entrance requirement to HE, their motivation and employment ambitions. Foreign language learning in secondary grammar schools appeared to be more favourable than in secondary technical schools.A magyar fiatalok nyelvtudásának javĂtása az elmĂşlt kĂ©t Ă©vtized fontos oktatáspolitikai cĂ©lkitűzĂ©se, az eredmĂ©nyek azonban nem meggyĹ‘zĹ‘ek Ă©s nagy eltĂ©rĂ©sek mutatkoznak a tanulĂłk nyelvtanulási eredmĂ©nyessĂ©gĂ©ben. A kutatások ezen kĂĽlönbsĂ©gek hátterĂ©t számos szempontbĂłl vizsgálták Ă©s magyarázták többek közt a motiváciĂł, a nyelvĂ©rzĂ©k, a tanulási stratĂ©giák, az attitűd Ă©s a családi háttĂ©r terĂĽletĂ©n mutatkozĂł eltĂ©rĂ©sekkel. Kutatásunkkal a társadalmi háttĂ©rbeli kĂĽlönbsĂ©gek nyelvtanulási eredmĂ©nyessĂ©gre gyakorolt hatásának további feltárására vállalkoztunk. Vizsgáltuk a gimnáziumi Ă©s szakgimnáziumi tanulĂłk nyelvtudásának helyzetĂ©t objektĂv Ă©s szubjektĂv szempontbĂłl, feltártuk a sikerek mögött meghĂşzĂłdĂł háttĂ©rtĂ©nyezĹ‘ket Ă©s elemeztĂĽk a nyelvtanulásra hatĂł iskolán kĂvĂĽli eszközöket Ă©s aktorokat. HipotĂ©ziseink szerint a gimnáziumi tanulĂłk idegennyelv-oktatása eredmĂ©nyesebb, mint a szakgimnáziumi tanulĂłkĂ©, az iskolai idegen nyelvi Ăłraszámok nem befolyásolják a tanulĂłk idegen nyelvi eredmĂ©nyessĂ©gĂ©t Ă©s a magasabb vĂ©gzettsĂ©gű szĂĽlĹ‘k gyermekei eredmĂ©nyesebbek.
KĂ©rdĹ‘Ăves pilot kutatásunkat 2018/19 fordulĂłján hĂ©t debreceni közĂ©piskola (nĂ©gy gimnázium Ă©s három szakgimnázium) 105 tanulĂłjának megkĂ©rdezĂ©sĂ©vel vĂ©geztĂĽk el 9.-12. Ă©vfolyamokon. A vizsgált tanulĂłk 34%-a rendelkezett nyelvvizsgával, de önĂ©rtĂ©kelĂ©ssel jelentĹ‘sen többen számoltak be közĂ©p- vagy felsĹ‘fokĂş nyelvtudásrĂłl. A tanulĂłk jelentĹ‘s többsĂ©ge vallotta magát sikeres nyelvtanulĂłnak, leginkább nyelvvizsga bizonyĂtványuk Ă©s beszĂ©dkĂ©szsĂ©gĂĽk miatt. A sikertelenek leginkább a nyelvvizsga hiánya miatt Ă©reztek kudarcot. EredmĂ©nyeink szerint a sikeres nyelvtanulás korrelál a szĂĽlĹ‘k iskolai vĂ©gzettsĂ©gĂ©vel Ă©s a tanulĂłk nyelvtudás fontosságárĂłl alkotott vĂ©lemĂ©nyĂ©vel, de nem állt összefĂĽggĂ©sben az idegen nyelv tantárgy heti Ăłraszámával az általános Ă©s közĂ©piskolában. NyelvvizsgaszerzĂ©si terveiket elsĹ‘sorban a felsĹ‘oktatási bemeneti kötelezettsĂ©g, saját belsĹ‘ motiváciĂłjuk, valamint hazai Ă©s kĂĽlföldi munkavállalási cĂ©lok motiválták. A nyelvtanulási körĂĽlmĂ©nyek a gimnáziumokban kedvezĹ‘bbnek mutatkoztak, mint a szakgimnáziumokban
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