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Wyszukujesz frazę "ultraviolet light" wg kryterium: Temat


Wyświetlanie 1-12 z 12
Tytuł:
Changes in the power (Watts) of the actinic light do not affect its better performance vs the ultraviolet light
Autorzy:
Matos da Costa, João
Powiązania:
https://bibliotekanauki.pl/articles/1193453.pdf
Data publikacji:
2021
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
actinic light
traps on insects
ultraviolet light
Opis:
Monitoring systems should be simple, time and cost effective, and collect as much information as possible, regarding the diversity of the communities under study. Most of studies use ultraviolet light traps to survey moths, although is known that the spectral sensitivity of moths has other wavelengths absorption peaks. As wider is the spectrum emitted by the lamps the wider is the fauna attracted and possible to be collected. The wider spectrum of actinic light, once it emits a large part of the ultraviolet wavelength as well as a peak at the blue, attracted more species than the ultraviolet light. In 2018 and 2019 the actinic light captured more species in 75% of the surveyed areas, while in 2020 in all areas. In 2018 and 2019, the power of the actinic light was 15 W and the ultraviolet light only 8 W. The actinic light trap captured, in 295 samples (50%), more species than the UV light trap which had a better performance in 201 samples (34%). In 2020 both light traps have the same power, 8 W, and results were similar, the actinic light collected more species in 123 samples (50%) than the ultraviolet light which in 48 samples (35%) collected more species than the actinic light.
Źródło:
World Scientific News; 2021, 157; 154-168
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Oxidation of short-chain isoprenoids
Autorzy:
Siedlecka, J.
Sosinska, E.
Kania, M.
Kaczorowska, E.
Cmoch, P.
Masnyk, M.
Lozinska, I.
Derewiaka, D.
Obiedzinski, M.
Czarnocki, Z.
Danikiewicz, W.
Swiezewska, E.
Powiązania:
https://bibliotekanauki.pl/articles/80737.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
conference
isoprenoid
short-chain isoprenoid
molecular structure
oxidation
reactive oxygen species
ultraviolet light
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2013, 94, 2
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Condense-Phase BBCEAS Measurements at UV Wavelength
Autorzy:
Nouna, Noora Sh. Oraha Qas
Powiązania:
https://bibliotekanauki.pl/articles/1190113.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Broadband cavity enhanced absorption spectroscopy
BBCEAS
Liquids
Absorption spectroscopy
Ultraviolet light emitted diode
UV-LED
Opis:
Broadband cavity enhanced absorption spectroscopy (BBCEAS) has been used to make measurements on liquid phase species using a UV LED and an optical cavity formed by R ≥ 0.99 ultra violet mirror set. The detector is an Andor CCD spectrograph. Measurements is made on a number of dyes dissolved in water and placed in a 1 cm quartz cuvette at zero degrees angle of incidence between the cavity mirrors. The most sensitive measurements are made with the R ≥ 0.99 mirror set on congo red at 397 nm which produced an αmin(t) value of 2.1 × 10-6 cm-1 Hz-1/2 and a LOD of 0.19 nM.
Źródło:
World Scientific News; 2016, 35; 17-29
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Droga pod słońce. Wczesna historia witaminy D
The route against the sun. Early history of vitamin D
Autorzy:
Wicha, J.
Powiązania:
https://bibliotekanauki.pl/articles/172567.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
witamina D
biosynteza i żywienie
sterole
badanie struktury
światło ultrafioletowe
dieta przeciwkrzywicza
historia witaminy D
vitamin D
biosynthesis
nutrition
sterols
structural investigations
ultraviolet light
antirachitic diet
Opis:
Two natural products are called „vitamin D”: (1) vitamin D3 which is biosynthesized in humans and animals and (2) vitamin D2 which is generated in photochemical rearrangement of a sterol of fungy – ergosterol (Fig. 1 and 2). The vitamins D are further metabolized (Scheme 1) first into 25-hydroxy- and then into 1.,25-dihydroxy derivatives in various tissues. The compounds control the calcium transport and act as a cell growth regulator important for tumor prevention. The early history of vitamin D stems from outburst of rickets at the beginning of the industrialization era. Rickets was a child bond disease that often led to a permanent disability. A comprehensive description of the rickets was presented by D. Whistler ( 1619–1684) and then F. Glisson (1597–1677) and coauthors. Jędrzej Śniadecki ( 1768–1838) was the first who associated the rickets with the sunlight. In his book “On the Physical Education of Children” Śniadecki stated that exposition of a child’s body to a direct action of sunlight is the most efficient method for the prevention and the cure of rickets (Illustrations 1 and 2). T. A. Palm in 1890 observed that the rickets is rare in countries where sunshine is abundant and prevalent whenever there is a little of sunlight. The first experimental evidence on the sunlight effects in rickets were presented by J. R aczyński in 1912 who postulated that the sunlight affects metabolic processes in blood related to calcium transport (Illustration 3 and 4). E. Mellanby showed (1919) that the disease is connected to the lack of certain dietary factors and he recommended the use of cod liver – oil. K. Huldschinsky experimentally proved that UV irradiation cures the rickets. The Mellanby’s and Huldschinsky’s observations were confirmed by clinical studies in 1922. E.V. McCollum has developed efficient methods for “biological analysis” of food and named anti-rachitic factor as vitamin D.H. Steenbock and A.F. Hess in 1924 found independently that various food products gain anti-rachitic properties after being irradiated with a UV lamp. A.F. Hees and A. Windaus showed that irradiation of ergosterol affords a product with high anti-rachitic activity. In 1919 the first structure for cholesterol has been proposed by A. Windaus (Scheme 2, Fig. 3) and then with contribution of H. Wieland it was modified to the “Wieland-Windaus” structure (1928, Nobel Price lectures, Fig. 4). O. Diels’ investigation on dehydratation of cholesterol (Fig. 5) and J.D. Bernal’s crystallographic measurements of ergosterol challenged the Wieland-Windaus structure. Finally, the correct structure for cholic acid and sterols was deduced by O. Rosenheim and H. King (Fig. 6). In 1932 crystalline vitamin D2 was prepared in the Windaus laboratory (Scheme 3). In 1935 vitamin D3 was isolated from a fish-oil and the same compound was synthesized from cholesterol (Illustration 5). The structure of vitamin D2 was elucidated by Windaus in 1935 (Illustration 6) and confirmed by X-ray studies in 1948. Scientific contributions of Adolf Windaus are associated with his highest ethical standards and non-conformist political position in the national-socialist age.
Źródło:
Wiadomości Chemiczne; 2012, 66, 7-8; 671-696
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photobiological safety of the recently introduced energy efficient household lamps
Autorzy:
Necz, Péter P.
Bakos, József
Powiązania:
https://bibliotekanauki.pl/articles/2179018.pdf
Data publikacji:
2014-12-01
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
ultraviolet
visible light
blue light
optical radiation
hazard
Opis:
Objectives: Nowadays more and more newly introduced light sources (tungsten-halogen, compact fluorescent (CFL) and light-emitting diode (LED) lamps) are used in households. It is important to know whether their radiation poses any possible risk for human health or not. These light sources emit optical radiation not solely in the visible spectrum. Other bands emitted by these sources, i.e., ultraviolet and infrared, are potentially hazardous for human health. The visible light, especially the blue light, could also damage human retina. The purpose of this study was to determine the ultraviolet (UV) and blue light (BL) emissions from halogen bulbs, CFLs and LED lamps, and to evaluate them from the point of view of possible health risks for general public. Material and Methods: The exposure of UV and BL emissions from 19 types of CFLs, 11 types of halogen lamps and 4 types of LED lamps produced by different manufacturers were measured at 200 mm distance from the source. Results: The exposures to UV and BL were below the International Commission on Non-Ionizing Radiation Protection (ICNIRP) exposure limits in spite of the very conservative assumption of the assessment. Conclusions: Results of this study indicate that the UV and BL radiation from the newly introduced lamps does not exceed the current exposure limit values and thus, in comparison with the former incandescent bulbs, does not result in a higher risk for general public.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2014, 27, 6; 1036-1042
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of the compositional graded quaternary barrier AlGaN-based ultraviolet-C light-emitting diode
Autorzy:
Malik, S.
Usman, Muhammad
Hussain, M.
Munsif, M.
Khan, S.
Rasheed, S.
Ali, S.
Powiązania:
https://bibliotekanauki.pl/articles/1818198.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
ultraviolet
light-emitting diodes
efficiency
quantum wells
Opis:
The compositional graded quaternary barriers (GQBs) instead of ternary/conventional quantum barriers (QBs) have been used to numerically enhance the efficiency of AlGaN-based ultraviolet light-emitting diode (LED). The performance of LED with GQBs is examined through carrier concentrations, energy band diagrams, radiative recombination, electron and hole flux, internal quantum efficiency (IQE), and emission spectrum. As a function of the operating current density, a considerable reduction in efficiency droop is observed in the device with composition-graded quaternary barriers as compared to the conventional structure. The efficiency droop in case of a conventional LED is ~77% which decreased to ~33% in case of the proposed structure. Moreover, the concentration of electrons and holes across the active region in case of the proposed structure is increased to ~156% and ~44%, respectively
Źródło:
Opto-Electronics Review; 2021, 29, 3; 80--84
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of the compositional graded quaternary barrier AlGaN-based ultraviolet-C light-emitting diode
Autorzy:
Malik, S.
Usman, Muhammad
Hussain, M.
Munsif, M.
Khan, S.
Rasheed, S.
Ali, S.
Powiązania:
https://bibliotekanauki.pl/articles/1818193.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
ultraviolet
light-emitting diodes
efficiency
quantum wells
Opis:
The compositional graded quaternary barriers (GQBs) instead of ternary/conventional quantum barriers (QBs) have been used to numerically enhance the efficiency of AlGaN-based ultraviolet light-emitting diode (LED). The performance of LED with GQBs is examined through carrier concentrations, energy band diagrams, radiative recombination, electron and hole flux, internal quantum efficiency (IQE), and emission spectrum. As a function of the operating current density, a considerable reduction in efficiency droop is observed in the device with composition-graded quaternary barriers as compared to the conventional structure. The efficiency droop in case of a conventional LED is ~77% which decreased to ~33% in case of the proposed structure. Moreover, the concentration of electrons and holes across the active region in case of the proposed structure is increased to ~156% and ~44%, respectively.
Źródło:
Opto-Electronics Review; 2021, 29, 3; 80--84
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fotoporządkowanie : alternatywna technika dla szybkich przetworników ciekłokrystalicznych
Photoalignment : an alternative aligning technique for fast liquid crystal shutter
Autorzy:
Chrzanowski, M. M.
Zieliński, J.
Nowinowski-Kruszelnicki, E.
Olifierczuk, M.
Powiązania:
https://bibliotekanauki.pl/articles/210044.pdf
Data publikacji:
2010
Wydawca:
Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
Tematy:
fotoporządkowanie
izomeryzacja cis-trans
sieciowanie krzyżowe
fotodegradacja
model dyfuzyjny
LCD (ang. liquid crystal display, wyświetlacz ciekłokrystaliczny)
LPP (ang. Linear photopolymerization, fotopolimeryzacja liniowa)
LPUV (ang. linear polarized ultraviolet light, światło ultrafi oletowe spolaryzowane liniowo)
LC (ang. liquid crystal, ciekły kryształ)
photoalignment
cis-trans isomerization
diffusion model
photodegradation
crosslinking
LCD
LPP
LPUV
LC
Opis:
W artykule podjęto temat wyboru techniki fotoporządkowania ciekłego kryształu. Technologia ta jest alternatywą dla najczęściej stosowanego rubbingu, czyli jednostronnego polerowania warstw poliimidowych i poliamidowych. Zarówno w przypadku rubbingu (buffingu), który ma naturę kontaktową, jak i bezkontaktowego fotoporządkowania efektem pracy jest wytworzenie anizotropii warstwy, która następnie ma za zadanie porządkować leżącą bezpośrednio na niej warstwę ciekłego kryształu (LC). Rubbing jest metodą stosunkowo prostą i tanią i jest zwyczajowo używany przy produkcji wyświetlaczy ciekłokrystalicznych. W trakcie polerowania mogą jednak powstawać uszkodzenia struktury matrycy aktywnej oraz tworzyć się pyły, które są szkodliwe zwłaszcza dla bardzo cienkich warstw ciekłego kryształu. W związku z tym poszukuje się metod alternatywnych porządkowania. Z fotoporządkowaniem mamy do czynienia wtedy, gdy anizotropia warstwy porządkującej wywołana jest przez ekspozycję materiału fotoczułego na działanie światła ultrafioletowego spolaryzowanego liniowo. Jest to proces bezkontaktowy, więc eliminuje on większość wymienionych wcześniej wad rubbingu. Ponadto umożliwia pracę na plastycznych oraz zakrzywionych podłożach. Istnieją cztery różne drogi realizacji procesu fotoporządkowania warstwy światłoczułych materiałów organicznych: 1) fotodegradacja w materiałach poliimidowych, 2) izomeryzacja cis-trans azozwiązków, 3) czysta reorientacja związków azowych w polu potencjału światła UV oraz 4) sieciowanie w strukturze polimerowej. W pracy przedstawiono krytyczny przegląd wyżej wymienionych metod. Zastosowanie fotoporządkowania badane jest pod kątem przydatności w komórkach działających w oparciu między innymi o efekty: FLC (ang. ferroelectric liquid crystal, ciekły kryształ ferroelektryczny), TN (ang. twisted nematic, skręcony nematyk), BTN (ang. bistable twisted nematic, bistabilny skręcony nematyk), VAN (ang. vertical alignment nematic, pionowa deformacja fazy nematycznej), IPS (ang. in plane switching, przełączanie w płaszczyźnie) i inne. Celem poniższej pracy jest porównanie i określenie przydatności różnych metod fotoporządkowania dla technologii przetworników ciekłokrystalicznych o dużej jasności zobrazowania.
In this study we consider the topic of the photoalignment of liquid crystal material. It is an alternative method to the rubbing of polyimide and polyamide layers. Both techniques provide the anisotropy in organic layers. This anisotropy aligns overlaying liquid crystal. The rubbing is a well known and cheap technique and it's ordinarily used in liquid crystal displays manufacturing. However, it has several disadvantages, for example it produces dust particles and charges the layer. Furthermore it may damage the surface electronic. These drawbacks can be critical factors in working with thin liquid crystal layers (about 2-5 µm) for example ferroelectric and antiferroelectric Lcs. Heterogeneity at the microscopic level can be noxious especially in the area of some types of liquid crystals and in manufacturing high-resolution liquid crystal displays (over 40”) and state-of-art projector display systems. In order to omit these problems, very important for the future work is to develop a new, universal and high-performance, technique for liquid crystal aligning. One of alternatives is photoalignment. It eliminates many of drawbacks mentioned above. This technique uses light (generally linearly polarized ultraviolet light, LPUV) to produce anisotropy in photodephiniable materials. In addition this technique allows us to obtain layers on plastic or curve surfaces. We can distinguish four main photoalignment mechanisms (including photo-chemical reactions and photo-physical changes): (1) cis-trans isomerization in azo-structures: pure dyes films, polymers containing azo-groups and monolayers of azodyes, (2) pure reorientation of photo-chemically stable azo-dyes molecules, (3) photodegradation in polyimide materials and (4) crosslinking in cinnamoyl and coumarin side-chain polymers. There are some modifications among these procedures, such as polymerizable azo-dyes or Langmuir-Blodgett films. Photoalignment is investigated in diverse liquid crystal modes, such as: twisted nematic (TN), vertical alignment (VAN), in plane switching (IPS) and many others. In this paper we describe all of the photoalignment mechanisms mentioned above and compare their ability to align the liquid crystal material in the field of application in various modes of LC cells.
Źródło:
Biuletyn Wojskowej Akademii Technicznej; 2010, 59, 3; 375-394
1234-5865
Pojawia się w:
Biuletyn Wojskowej Akademii Technicznej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Method of determining photobiological safety of contemporary light sources
Autorzy:
Pawlak, A.
Powiązania:
https://bibliotekanauki.pl/articles/134950.pdf
Data publikacji:
2015
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
photobiological hazard
ultraviolet radiation
infrared radiation
visible radiation
blue light hazard
risk group
safe exposure time
lighting source
light emitting diode (LED)
Opis:
The article presents a method of evaluating irradiance, spectral irradiance, and spectral radiance, for purposes of determining risk groups of sources of light. The description of the method of measurement of radiance incorporates standard and alternative methods. Measurement methods were developed on the basis of general requirements and diagrams incorporated in the standard PN-EN 62471: 2010. The paper classifies risk groups of sources of light in terms of photobiological hazards and exposure limits when skin is at risk of being damaged by visible and infrared radiation. Threshold values of emissions for the continuous sources of radiation studied are presented. The article describes environmental conditions under which the measurements are to be taken, and requirements applicable to the process of light source aging. In addition, technical assumptions are presented, and the design of the test stand for measuring optical radiation parameters is described.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2015, 43 (115); 29-36
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bezpieczeństwo fotobiologiczne zamienników żarówek
Lamps and lamp systems classification according to the photobiological safety
Autorzy:
Pawlak, A.
Powiązania:
https://bibliotekanauki.pl/articles/159405.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Elektrotechniki
Tematy:
bezpieczeństwo fotobiologiczne
grupy ryzyka
promieniowanie nadfioletowe
zagrożenie światłem niebieskim
photobiological safety
risk groups
ultraviolet radiation
blue light hazard
Opis:
W artykule, na podstawie zapisów normy PN-EN 62471:2010, scharakteryzowano wytyczne dotyczące oceny bezpieczeństwa fotobiologicznego lamp i systemów lampowych. Zaprezentowano dozwolone czasy bezpiecznej ekspozycji oraz wartości graniczne emisji dla poszczególnych, określonych przez normę, czterech grup ryzyka. Przedstawiono kryteria pomiaru natężenia napromienienia lub luminancji energetycznej badanych lamp. Omówiono zagrożenia związane z promieniowaniem nadfioletowym, widzialnym i podczerwonym. W celu szczegółowego przedstawienia potencjalnych zagrożeń związanych ze światłem niebieskim, dokonano porównania widm wybranych źródeł światła. Na tej podstawie dokonano oceny zagrożenia światłem niebieskim wybranych źródeł światła.
The article, based on the records of the PN-EN 62471:2010, presents guidelines for photobiological safety of lamps and lamp systems. There are allowed safe exposure times presented and emission limit values for each of four risk groups, defined by the standard. The paper presents criteria for lamps irradiance or radiance measurement. Discussed risks with association of ultraviolet, visible and infrared radiation. For a detailed presentation of the potential risks associated with the blue light, there is made a comparison of spectra of selected light sources. On these basis, the blue light hazard assessment was presented for selected light sources.
Źródło:
Prace Instytutu Elektrotechniki; 2015, 269; 67-81
0032-6216
Pojawia się w:
Prace Instytutu Elektrotechniki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photobiological safety of incandescent lamp replacements
Autorzy:
Pawlak, A.
Powiązania:
https://bibliotekanauki.pl/articles/2064438.pdf
Data publikacji:
2018
Wydawca:
STE GROUP
Tematy:
photobiological safety
risk groups
ultraviolet radiation
blue light hazard
bezpieczeństwo fotobiologiczne
grupy ryzyka
promieniowanie ultrafioletowe
zagrożenie światłem niebieskim
Opis:
The article, based on the records of the EN 62471:2008, presents guidelines for photobiological safety of lamps and lamp systems. There are allowed safe exposure times presented and emission limit values for each of four risk groups, defined by the standard. The paper presents criteria for lamps irradiance or radiance measurement. Discussed risks with association of ultraviolet, visible and infrared radiation. For a detailed presentation of the potential risks associated with the blue light, there is made a comparison of spectra of selected light sources. On these basis, the blue light hazard assessment was presented for selected light sources.
Źródło:
New Trends in Production Engineering; 2018, 1, 1; 87-94
2545-2843
Pojawia się w:
New Trends in Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The contribution of fluorescence to measurements of light scattering in oil-in-water emulsions
Autorzy:
Stelmaszewski, A.
Powiązania:
https://bibliotekanauki.pl/articles/48940.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
contribution
emulsion
fluorescence
light scattering
marine environment
measurement
oil pollution
oil-water emulsion
petroleum
sea water
ultraviolet radiation
Opis:
The paper presents some results of research on the fluorescence properties of petroleum oil-in-water emulsions. The research addresses the question of measuring and modelling light fields in an oil-polluted marine environment. The fluorescence of the emulsion manifests itself in the spectral range from 260 to over 400 nm and is much less intensive in the visible light region. Fluorescence is always weaker than the radiation scattered in an emulsion. The measurement and modelling of ultraviolet radiation scattering requires fluorescence to be taken into consideration, but in the visible spectral region this phenomenon is negligible.
Źródło:
Oceanologia; 2011, 53, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
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