Resonant transmission through negative permittivity materials

At the heart of the field of photonics is the control of the reflection and transmission of light. Plasmonics looks at this problem of control of electromagnetic radiation in the context of surface plasmon polaritons (SPP). SPPs are propagating electromagnetic modes localized at the interfaces between media with positive and negative permittivities. Their excitation can accompany the enhancement of transmission, reflection, or absorption of EM radiation. There are a number of ways to excite SPPs and this work looks at several geometries and analyzes the transmission and reflection characteristics using a numerical approach based on the finite element method. The first method of excitation is by incident evanescent wave that was totally internally reflected from an earlier interface. It is shown that an evanescent wave can excite SPPs and create resonant transmisison. It is also found that high values of dissipation limit transmission and instead create resonant absorption. The second method involves the modulation of the negative permittivity of the plasma slab itself. Numerical results are compared to analytical ones and are in good agreement because harmonics of the solution above the first are negligible. An investigation of transmission through a plasma slab with a single thin diffraction grating placed nearby follows. Analytical and numerical calculations show that a single thin grating is sufficient to create transmission resonance. It is found that for large values of diffraction grating modulation parameter, higher harmonics, usually not accounted for in analytical solutions, results in discrepancies between analytical and numerical results. The next geometry considered is of a plasma layer with only part of it having modulated permittivity. The presence of modulation of only part of the plasma layer is shown to create transmission and reflection resonances. By tailoring parameters of the system, it is shown how the resonant frequencies can be shifted. The final geometry considers a copper grating beside a plasma and transmission of a radio frequency wave. Even though the copper used here in this simulation is very absorbing, there are ranges of frequencies when transmission or reflection are enhanced

The problems and outcomes of the industrial land redevelopment in Visegrad countries

Peer Reviewe

Belastungsdimension beim Skibergsteigen

Die steigende Nachfrage naturverbundener Menschen nach einer geeigneten Wintersportart abseits von Skipisten führte nicht am Skibergsteigen vorbei. Der aufkommende Trend in den letzten Jahren wurde nicht zuletzt durch das Wettkampf-Skibergsteigenden über die Medien populärer gemacht. Der Wunsch vieler Menschen eine gesunde Sportart betreiben zu können trug zu seiner Verbreitung bei. Ebenso führten die steigenden Preise im Tourismus von alpinen Skiregionen zu einem Wandel in Richtung Skibergsteigen. Da das Leistungsvermögen beim Skibergsteigen von vielen exogenen Faktoren, wie Kälte, Wind und Strahlenbelastung, und endogenen kardiopulmonal-metabolischen Parametern beeinflusst wird und der menschliche Organismus auf individueller Weise darauf reagiert, entstand das Interesse motorische und psychische Belastungskomponenten, sowie die Thermoregulation und die Höhenanpassung auf analytisch-qualitativer Weise zu erforschen. Der Gegenstand dieser qualitativen Untersuchungen war, zu zeigen, ob das Skibergsteigen mit Sportarten ähnlichem Belastungsprofils, hinsichtlich motorischer und psychischer Belastungen, der Thermoregulation und der Höhenanpassung vergleichbar ist. Aufgrund der defizitären Literaturlage mussten die formulierten H0-Hypothesen beibehalten werden. Deshalb ist auf diesem Gebiet weitere quantitative Forschung notwendig, um die physiologische Belastung beim Skibergsteigen feststellen, und wissenschaftlich begründete Trainingsempfehlungen für diese populäre Sportart geben zu können.The rising Interest on outdoor oriented winter sports aside prepared ski slopes was also the driving force for ski mountaineering. Media, and the desire for healthy outdoor sports was one of the reason why ski mountaineering is getting that popular nowadays. An other reason for the rising popularity could be the high pricing of alpine skiing areas. As the capacity of ski mountaineering is dedicated by many exogenous factors like cold, wind and ray load and endogenous cardio-pulmonal metabolic parameters that are all individual there was a big interest to investigate the motor and psychic load components as well as the thermo regularisation and the height adaptation in an analytic qualitative manner. The object of these qualitative investigations was to show if the ski mountaineering is comparable with sports to similar load profile, concerning motor and psychic charges, the thermo regularisation and the height adaptation. On account of the deficit literature situation the formulated H0 hypotheses had to be maintained. However, further research in this area, especially quantitative data are necessary to determine physiological load of ski-mountaineering end to be able to establish science based recommendations for training in this popular outdoor activity

Exciton diffusion and interactions with a two-dimensional Fermi sea

Two-dimensional semiconductors such as monolayer transition metal dichalcogenides (TMDCs) evolved to a versatile platform to explore elementary optoelectronic phenomena. In these systems, excitons with firm light-matter coupling and spin-valley locking dominate the optical properties. Due to strong Coulomb forces, TMDCs are a particularly promising system to study the interplay between excitons, phonons and electrons at previously inaccessible experimental conditions. In this thesis, exciton diffusion and interactions with a two-dimensional Fermi sea of free charge carriers are investigated. In carrier density-dependent reflectance spectra of electrically-tuneable hBN-encapsulated WSe₂ monolayers negatively- and positively-charged excited state trions are identified. Their binding energies and oscillator strengths are determined and autoionization is studied, a process which is typically associated with excited states in atomic systems. Exciton-carrier scattering rates are extracted from voltage-dependent spectral reflectance and luminescence linewidth broadening and the interplay of exciton-phonon and exciton-carrier scattering is investigated. By analyzing the trion ground state low-energy recoil flank in time-resolved luminescence experiment, trion cooling times in monolayer MoSe₂ are determined. With increasing temperature and charge carrier density an accelerated cooling is observed. Taking advantage of time-resolved microscopy, exciton propagation is investigated at cryogenic temperatures. Temperature-dependent diffusion experiments reveal mobile dark excitons and signatures of non-classical exciton propagation, contradicting the widely-used semiclassical description of exciton kinetics in TMDCs. In carrier density-dependent diffusion experiments, mobile trions and the impact of exciton-carrier scattering and trion formation on the propagation are explored

Housing Market Information in CEE countries

The paper aims to show how the historical development of CEE countries and their institutional framework has influenced the quality of information on housing markets. Central and Eastern European countries (CEE) have undergone the serious economic and institutional transformation. The functioning of the residential sector was changed by introducing the new institutions, regulations, housing finance institutions and internet. The newly established residential markets, the actors operating on these markets, and the governments (both national as well as EU) have generated the demand for better information. This was partially fulfilled, yet the quality of the information on the residential markets is still lagging behind the developed Western economies. Moreover there is clear lack of the historical market data, which make the decision making regarding the regulation of the markets and the mortgage provision more risky. The global economic crisis has uncovered the economic vulnerabilities of the CEE and their residential markets. At the same time the crisis created the serious pressure for more responsible investments and higher efficiency, and the triggered demand for higher quality and more comprehensive information on the residential markets

Peter Fendi und das einfigurige Wiener Sittenbild

Peter Fendis Bedeutung innerhalb der österreichischen Malerei der Biedermeierzeit mit besonderem Augenmerk auf seine Leistungen bei der Entwichlung der Sonderform des einfigurigen Wiener Sittenbildes.Peter Fendi and his position in austrian painting of the biedermeier period and his achievements developing the single figure genre paintin

Growth of the IMC at the interface of SnAgCuBi (Bi = 0,5; 1,0) solder joints with Cu substrate

Ovdje se analizira utjecaj dodavanja Bi na stvaranje intermetalne faze u bezolovno lemljenim spojevima od Sn-Ag-0.5Cu0.5Bi (SAC0,5B) i Sn-Ag-0.5Cu-1.0Bi (SAC1,0B), sastav dan u težinskim %, na bakrenoj podlozi. Lemljenje bakrene ploče je provedeno na 255 °C u trajanju od 5 s. Spojevi su zatim ostavljeni na temperaturi od 100 °C, 130 °C i 160 °C u trajanju od 1, 3, 7, 15 dana u konvekcijskoj peći. Međupovršine su tada analizirane optičkim mikroskopom i energetskom disperzivnom rendgenskom spektrometrijskom mikroanalizom (EDX, JEOL-JXA-840A). Dva intermetalna sloja su zapažena na međupovršini - Cu3Sn i Cu6Sn5. Sloj Cu6Sn5 je nastao tijekom lemljenja. Sloj Cu3Sn je nastao tijekom sazrijevanja u čvrstom stanju. Dodavanjem Bi smanjuje se nastanak Cu3Sn jer se tako sprječava širenje Sn duž granica zrna. U članku se dalje raspravlja mehanizam nastanka sloja Cu6Sn5 i daju se zaključci za optimalni kemijski sastav lemila.The effects of Bi addition on the intermetallic phase formation in the lead-free solder joints of Sn-Ag-0.5Cu0.5Bi (SAC0,5B) and Sn-Ag-0.5Cu-1.0Bi (SAC1,0B), composition given in weight (measured in %), with copper substrate are studied. The soldering of the copper plate was conducted at 255 °C for 5 s. The joints were subsequently aged at temperatures of 100 °C, 130 °C and 160 °C for 1, 3, 7, 15 days in a convection oven. The aged interfaces were analysed by the optical microscopy and energy dispersive x-ray spectrometry (EDX, JEOL-JXA-840A) microanalysis. Two intermetallic layers are observed at the interface – Cu3Sn and Cu6Sn5. Cu6Sn5 is formed during soldering. Cu3Sn is formed during solid state ageing. Bi decreases the growth rate of Cu3Sn since it can possibly inhibit Sn diffusion along the grain boundaries. The mechanism of the Cu6Sn5 layer growth is discussed and the conclusions for the optimal solder chemical composition are presented

Effect of Soil Conditioning on the Moisture Content and the Salt Profile of the Soil Under Irrigation with Saline Water

L