PAM (pulse amplitude modulation) fluorometers can be used to estimate the electron transport rate (ETR) [μmol(e-) m-2 s-1] from photosynthetic yield determinations, provided the absorptance (Abtλ) of the photoorganism is known. The standard assumed value used for absorptance is 0.84 (leaf absorptance factor, AbtF). We described a reflectance-absorptancetransmittance (RAT) meter for routine experimental measurements of the actual absorptance of leaves. The RAT uses a red-green-blue (RGB) LED diode light source to measure absorptances at wavelengths suitable for use with PAM fluorometers and infrared gas analysers. Results using the RAT were compared to Abtλ spectra using a Taylor integrating sphere on bird’s nest fern (Asplenium nidus), banana, Doryanthes excelsa, Kalanchoe daigremontiana, and sugarcane. Parallel venation had no significant effect upon Abt465 in banana, Doryanthes, a Dendrobium orchid, pineapple, and sugarcane, but there was a slight difference in the case of the fern A. nidus. The average Abt465 (approximately 0.96) and Abt625 (approximately 0.89) were approximately 14% and 6% higher than the standard value (AbtF = 0.84). The PAR-range Abt400-700 was only approximately 5% higher than the standard value (approximately 0.88) based on averaged absorptance from the blue, green, and red light data and from where the RGB-diode was used as a ‘white’ light source. In some species, absorptances at blue and red wavelengths are quite different (e.g. water lily). Reflectance measurements of leaves using the RAT would also be useful for remote sensing studies., R. J. Ritchie, J. W. Runcie., and Obsahuje bibliografii
This paper deals with artificial lighting calculation in interiors by means of the computer program Wils 6.3. The distribution of illuminance and glare factor for a given room was investigated at different conditions (e. g. at change of number and location of luminaries, colour of single walls, location of impediment to the room etc.). A relatively fast calculation of light quantities at change of specific input parameters belongs to advantages of these simulations. and Předmětem tohoto příspěvku je výpočet umělého osvětlení vnitřních prostor pomocí počítačového programu Wils 6.3. Pro danou místnost bylo zkoumáno rozložení osvětlenosti a činitele oslnění při různých podmínkách (např. při změně počtu a rozmístění svítidel, barvy jednotlivých stěn, umístění překážky v místnosti apod.). K výhodám těchto simulací patří poměrně rychlý výpočet světelných veličin při změně určitých vstupních parametrů.
Here experience and results achieved by measurement and subsequent calculation of optical parameters of AlF3 thin film on SF1-glass substrate are given. and Predkladáme výsledky z merania a následných výpočtov optických parametrov tenkej vrstvy AlF3 na substráte skla SF1. K nameranému priebehu odrazivosti povrstvenej vzorky bol fitovaný simulačný model odrazivosti jednoduchej tenkej vrstvy na semi-infinitnom substráte. Výsledný priebeh indexu lomu a hrúbky vrstvy bol porovnávaný pre tri merania v rôznych spektrálnych šírkach.
We conducted an experiment to assess the predictive capability of a leaf optical meter for determining leaf pigment status of Acer mono Maxim., A. ginnala Maxim., Quercus mongolica Fisch., and Cornus alba displaying a range of visually different leaf colors during senescence. Concentrations of chlorophyll (Chl) a, Chl b, and total Chl [i.e., Chl (a+b)] decreased while the concentration of carotenoids (Car) remained relatively static for all species as leaf development continued from maturity to senescence. C. alba exhibited the lowest average concentration of Chl (a+b), Chl a, and Car, but the highest relative anthocyanin concentration, while Q. mongolica exhibited the highest Chl (a+b), Chl b, and the lowest relative anthocyanin concentration. A. mono exhibited the highest Chl a and Car concentrations. The relationships between leaf pigments and the values measured by the optical meter generally followed an exponential function. The strongest relationships between leaf pigments and optical measurements were for A. mono, A. ginnala, and Q. mongolica (R2 ranged from 0.64 to 0.95), and the weakest relationships were for C. alba (R2 ranged from 0.13 to 0.67). Moreover, optical measurements were more strongly related to Chl a than to Chl b or Chl (a+b). Optical measurements were not related to Car or relative anthocyanin concentrations. We predicted that weak relationships between leaf pigments and optical measurements would occur under very low Chl concentrations or under very high anthocyanin concentrations; however, these factors could not explain the weak relationship between Chl and optical measurements observed in C. alba. Overall, our results indicated that an optical meter can accurately estimate leaf pigment concentrations during leaf senescence - a time when pigment concentrations are dynamically changing - but that the accuracy of the estimate varies across species., Future research should investigate how species-specific leaf traits may influence the accuracy of pigment estimates derived from optical meters., G. Y. Li, D. P. Aubrey, H. Z. Sun., and Obsahuje bibliografii
In radiometric measurement of the object temperature, in measurement and evaluation of heat escape from buildings we meet with materials, which can be characterised as transparent or semitransparent. One of them is glass. The objective of the present article is to analyse glass features, including emissivity in dependence to wavelength and temperature and also the thermal transmissivity of glass. and Pri bezkontaktných meraniach teploty objektov, pri meraní a vyhodnotení úniku tepla z budov sa stretávame s materiálmi, ktoré možno označiť ako priezračné alebo polopriepustné. Jedným z bežne používaných materiálov je sklo. V príspevku sa pokúšame analyzovať vlastnosti skla, jeho emisivitu v závislosti na vlnovej dĺžke a teplote.