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Start Over Rights http://creativecommons.org/licenses/by-nc-sa/4.0/ Date Unknown

29904. Theory and modeling of guided-wave photonic structures

Creator:
Čtyroký, Jiří
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
integrated optics, optical waveguide theory, plasmonics, nanophotonics, integrovaná optika, optická vlnovodná teorie, plasmonika, and nanofotonika
Language:
Czech
Description:
Numerical modeling is an indispensable part of theory and design of any guided-wave photonic structure and device. It helps not only save time and money by substituting expensive and time consuming trial and error fabrication and testing by numerical simulations, but - even more importantly - it significantly contributes to proper understanding of physics involved in the operation of the structures or devices under study. In the Institute of Photonics and Electronics, this discipline has been systematically developed for more than three decades. In this communication, after a few examples of the most important achievements, we present fundamentals of the 3-D Fourier modal method recently developed and describe some results of its application to subwavelength grating waveguide structures based on silicon on insulator platform. and Numerické modelování je nepostradatelnou součástí teorie a návrhu jakékoli vlnovodné fotonické struktury a součástky. Pomáhá nejen ušetřit čas i peníze náhradou nákladné a časově náročné přípravy metodou pokusů a omylů numerickými simulacemi, ale také - a to zejména - významně přispívá k opravdovému porozumění fyzikálním jevům, na nichž je funkce těchto struktur či součástek založena. Tento obor je v Ústavu fotoniky a elektroniky AVČR systematicky rozvíjen již víc než tři desetiletí. Po několika příkladech nejvýznamnějších výsledků jsou v tomto příspěvku stručně popsány základy nedávno vyvinuté fourierovské modální metody pro modelování trojrozměrných fotonických struktur a jsou uvedeny některé výsledky její aplikace na křemíkové subvlnové mřížkové vlnovodné struktury.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

29905. Theory of evapotranspiration. 1.. Transpiration and its quantitative description

Creator:
Budagovskyi, Anatolij Ivanovič and Novák, Viliam
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
evapotranspiration, transpiration, evaporation, soil water, water balance, evapotranspirácia, transpirácia, evaporácia, pôdna voda, and bilancia vody
Language:
Slovak
Description:
Basic information about the evapotranspiration and its components is presented. System of equations describing the transport of water and energy in the soil - plant continuum is analyzed. The system of five differential equations with five unknowns is proposed, describing transport of heat and water vapour within the plant canopy, including exchange processes among the leaves and the atmosphere, vertical transport of the heat, water vapour and the energy balance. and Príspevok obsahuje základné informácie o evapotranspirácii a jej zložkách, výpare a transpirácii. Proces prenosu vody a energie v systéme pôda - porast je opísaný systémom piatich diferenciálnych rovníc kvantifikujúcich prenos vodnej pary a tepla medzi listami a atmosférou, ktoré umožnujú výpočet charakteristík vertikálneho prenosu vody a tepla v poraste a tiež bilanciu energie v tomto systéme.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

29906. Theory of evapotraspiration. 2.. Soil and intercepted water evaporation

Creator:
Budagovskyi, Anatolij Ivanovič and Novák, Viliam
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
evapotranspiration, transpiration, evaporation, soil water, water balance, evapotranspirácia, transpirácia, evaporácia, pôdna voda, and bilancia vody
Language:
Slovak
Description:
Evaporation of water from the soil is described and quantified. Formation of the soil dry surface layer is quantitatively described, as a process resulting from the difference between the evaporation and upward soil water flux to the soil evaporating level. The results of evaporation analysis are generalized even for the case of water evaporation from the soil under canopy and interaction between evaporation rate and canopy transpiration is accounted for. Relationships describing evapotranspiration increase due to evaporation of the water intercepted by canopy are presented. Indirect methods of evapotranspiration estimation are discussed, based on the measured temperature profiles and of the air humidity, as well as of the net radiation and the soil heat fluxes. and Príspevok obsahuje kvantitatívny opis výparu vody z pôdy a bilanciu energie počas vyparovania, charakterizovanú rovnicou obsahujúcou turbulentný tok tepla a skupenské teplo vyparovania. Je opísaný proces tvorby suchej vrstvy na povrchu pôdy počas výparu; jeho tvorba závisí od rozdielu medzi rýchlosťou výparu a prítokom vody k horizontu výparu zo spodnej vrstvy pôdy.Výsledky analýzy možno použiť aj na kvantifikáciu výparu z pôdy pod porastom. Uvádzajú sa vzťahy na výpočet zvýšenia rýchlosti evapotranspirácie, spôsobenej intercepciou. Práca obsahuje analýzu nepriamych metód výpočtu evapotranspirácie, ktoré sú založené na meraní profilov teploty a vlhkosti vzduchu nad vyparujúcim povrchom, ako aj radiačnej bilancie a tokov tepla v pôde.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

29907. There is no diploid apomict among Czech Sorbus species: a biosystematic revision of S. eximia and discovery of S. barrandienica

Creator:
Vít, Petr, Lepší, Martin, and Lepší, Petr
Type:
article, model:article, and TEXT
Subject:
apomixis, Czech Republic, endemic, geometric morphometrics, hybridization, karyology, multivariate morphometrics, Rosaceae, Sorbus latifolia agg., SSR markers, and taxonomy
Language:
English
Description:
Sorbus eximia Kovanda, a hybridogenous species that originated from the parental combination S. torminalis and S. aria s.l., is thought to be an apomictic species, which includes diploid and tetraploid individuals. The present study confirmed the existence of only triploid individuals. A new tentatively apomictic triploid (2n = 3x = 51) species from the S. latifolia group: S. barrandienica P. Vít, M. Lepší et P. Lepší is described based on a revision of S. eximia. This species is assumed to have originated from a cross between S. danubialis or S. aria s.l. and S. torminalis. A wide palette of biosystematic techniques, including molecular (nuclear microsatellite markers) and karyological analyses (chromosome counts, DAPI flow cytometry) as well as multivariate morphometric and elliptic Fourier analyses, were used to assess the variation in this species and justify its independent taxonomic status. Allopatric occurrences of both species were recorded east of the town of Beroun in the Český kras, central Bohemia (Bohemian Karst). A distribution map of the two species is provided. Sorbus eximia occurs at four localities (the total number of adults and juveniles is 100 and 200, respectively) in basiphilous thermophilous oak forests (Quercion pubescenti-petraeae), mesic oak forests (Melampyro nemorosi-Carpinetum), woody margins of dry grasslands (Festucion valesiacae) and pine plantations. Sorbus barrandienica has so far been recorded at 10 localities (ca 50 adults). Recent field studies failed to verify two of these localities. It is mainly found growing on the summits of hills, usually in thermophilous open forests (Primulo veris-Carpinetum, Melampyro nemorosi-Carpinetum, Quercion pubescenti-petraeae) and woody margins of dry grassland. Its populations exhibit minimal genetic variation and are phenotypically homogeneous and well separated from other Bohemian hybridogenous Sorbus species. The epitype of S. eximia is designated here, and a photograph of the specimen is included. Photographs of the type specimens and in situ individuals, and line drawings of both species are presented.
Rights:
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29908. Thermal acclimation of the temperature dependence of the VCmax of Rubisco in quinoa

Creator:
Bunce, J. A.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, carboxylation, mesophyll conductance, 2, and 581
Language:
Multiple languages
Description:
Changes in the temperature dependence of the maximum carboxylation capacity (VCmax) of Rubisco during thermal acclimation of PN remain controversial. I tested for acclimation of the temperature dependence of VCmax in quinoa, wheat, and alfalfa. Plants were grown with day/night temperatures of 12/6, 20/14, and 28/22°C. Responses of PN to substomatal CO2 (Ci) and CO2 at Rubisco (Cc) were measured at leaf temperatures of 10-30°C. VCmax was determined from the initial slope of the PNvs. Ci or Cc curve. Slopes of linear regressions of 1/VCmaxvs. 1/T [K] provided estimates the activation energy. In wheat and alfalfa the increases in activation energy with growth temperature calculated using Ci did not always occur when using Cc, indicating the importance of mesophyll conductance when estimating the activation energy. However, in quinoa, the mean activation energy approximately doubled between the lowest and highest growth temperatures, whether based on Ci or Cc., J. A. Bunce., and Obsahuje bibliografii
Rights:
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29909. Thermal dissipation during photosynthetic induction and subsequent dark recovery as measured by photoacoustic signals

Creator:
Buschmann, C.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
chlorophyll fluorescence, energy balance, heat production, induction kinetics, and photoacoustic spectroscopy
Language:
Multiple languages
Description:
The thermal photoacoustic signal (279 Hz) and the chlorophyll (Chl) fluorescence of radish cotyledons (Raphanus sativus L.) were measured simultaneously. The signals were recorded during a photosynthetic induction with actinic radiation of different quantum fluence rates [20, 200, and 1200 µmol(PAR-quantum) m-2 s-1]. The rise of these signals upon irradiation saturating photosynthesis was followed in the steady state of the induction and during the subsequent dark-recovery (i.e., in dark periods of 1, 5, 15, and 45 min after the induction). From these values various parameters (e.g., quantum yield, photochemical loss, different types of quenching coefficients) were calculated. The results show that heat dissipation detected by photoacoustic measurements is neither low, constant, nor always parallel to Chl fluorescence. Therefore, the thermal signal should always be measured in order to fully understand the way leaves convert energy taken up by PAR absorption. This helps in the interpretation of photosynthesis under different natural and anthropogenic conditions (stress and damage effects).
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

29910. Thermal phenomena modeling of aircraft electronic unit

Creator:
Ančík, Zdeněk and Vlach, Radek
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
thermal analyses, computational modelling, CFD, control electronic unit, and cooling systems
Language:
English
Description:
The aim of this paper is to show the complex thermal analyses used to design of aircraft electronic control unit. Control Power Supply for Jet (CPSJ). The goal is to examine thermal conditions of power and control electronics components. With respect to aircraft application a computational fluid dynamics (CFD) method is used for heat transfer coefficient determination. This method is compared to analytic solution based on Petuchov equation of Nusselt number. The temperature conditions inside the CPSI unit are presented as results. and Obsahuje seznam literatury
Rights:
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