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排序方式: 共有957条查询结果,搜索用时 15 毫秒
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Cellulose - Wet wipe dispersibility is broadly discussed since they have been detected in massive fatbergs that were found in sewer systems of big cities, e.g., London. Dispersibility describes a... 相似文献
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Effects of Ultraviolet Radiation (UVA+UVB) and Copper on the Morphology,Ultrastructural Organization and Physiological Responses of the Red Alga Pterocladiella capillacea 下载免费PDF全文
Éder C. Schmidt Marianne Kreusch Marthiellen R. de L. Felix Debora T. Pereira Giulia B. Costa Carmen Simioni Luciane C. Ouriques Francine L. Farias‐Soares Neusa Steiner Fungyi Chow Fernanda Ramlov Marcelo Maraschin Zenilda L. Bouzon 《Photochemistry and photobiology》2015,91(2):359-370
The effect of ultraviolet (UV) radiation and copper (Cu) on apical segments of Pterocladiella capillacea was examined under two different conditions of radiation, PAR (control) and PAR+UVA+UVB (PAR+UVAB), and three copper concentrations, ranging from 0 (control) to 0.62, 1.25 and 2.50 μm . Algae were exposed in vitro to photosynthetically active radiation (PAR) at 70 μmol photons m?2 s?1, PAR + UVB at 0.35 W m?2 and PAR +UVA at 0.70 W m?2 during a 12‐h photocycle for 3 h each day for 7 days. The effects of radiation and copper on growth rates, content of photosynthetic pigments and photosynthetic performance were analyzed. In addition, samples were processed for light and transmission electron microscopy. The content of photosynthetic pigments decreased after exposure to radiation and Cu. Compared with PAR radiation and copper treatments modified the kinetics patterns of the photosynthesis/irradiance curve. The treatments also caused changes in the ultrastructure of cortical and subcortical cells, including increased cell wall thickness and accumulation of plastoglobuli, as well as changes in the organization of chloroplasts. The results indicate that the synergistic interaction between UV radiation and Cu in P. capillacea, led to the failure of protective mechanisms and causing more drastic changes and cellular imbalances. 相似文献
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Differentiation between Shallow and Deep Charge Trap States on Single Poly(3‐hexylthiophene) Chains through Fluorescence Photon Statistics 下载免费PDF全文
Kristin S. Grußmayer Florian Steiner Prof. Dr. John M. Lupton Prof. Dr. Dirk‐Peter Herten Dr. Jan Vogelsang 《Chemphyschem》2015,16(17):3578-3583
Blinking of the photoluminescence (PL) emitted from individual conjugated polymer chains is one of the central observations made by single‐molecule spectroscopy (SMS). Important information, for example regarding excitation energy transfer, can be extracted by evaluating dynamic quenching. However, the nature of trap states, which are responsible for PL quenching, often remains obscured. We present a detailed investigation of the photon statistics of single poly(3‐hexylthiophene) (P3HT) chains obtained by SMS. The photon statistics provide a measure of the number and brightness of independently emitting areas on a single chain. These observables can be followed during blinking. A decrease in PL intensity is shown to be correlated with either 1) a decrease in the average brightness of the emitting sites; or 2) a decrease in the number of emitting regions. We attribute these phenomena to the formation of 1) shallow charge traps, which can weakly affect all emitting areas of a single chain at once; and 2) deep traps, which have a strong effect on small regions within the single chains. 相似文献
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Inside Back Cover: Differentiation between Shallow and Deep Charge Trap States on Single Poly(3‐hexylthiophene) Chains through Fluorescence Photon Statistics (ChemPhysChem 17/2015) 下载免费PDF全文
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Dr. Atena B. Solea Dr. Christophe Curty Prof. Dr. Katharina M. Fromm Prof. Dr. Christophe Allemann Prof. Dr. Olimpia Mamula Steiner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(55):e202201772
The toxicity of phosgene (COCl2) combined with its extensive use as a reactant and building block in the chemical industry make its fast and accurate detection a prerequisite. We have developed a carboxylic derivative of 5,6-pinenepyridine which is able to act as colorimetric and fluorimetric sensor for phosgene in air and solution. For the first time, the formation of a pyrido-[2,1-a]isoindolone was used for this purpose. In solution, the sensing reaction is extremely fast (under 5 s), selective and highly sensitive, with a limit of detection (LOD) of 9.7 nM/0.8 ppb. When fixed on a solid support, the sensor is able to detect the presence of gaseous phosgene down to concentrations of 0.1 ppm, one of the lowest values reported to date. 相似文献
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Dipl.-Ing. H. M. Müller Dr.-Ing. C. Hechler Prof. Dr.-Ing. D. Steiner Dipl.-Ing. E. U. Schlünder 《Heat and Mass Transfer》1982,17(1):47-53
Zusammenfassung Bei Messungen des Wärmeübergangs beim Strömungssieden von Argon wurde ein zeitlicher Anstieg der Wandtemperatur beobachtet, während die Einstellparameter Wärmestromdichte, Massenstromdichte, Dampfgehalt und Systemdruck konstant blieben. Dieser Temperaturanstieg endete nach mehreren Stunden bei einer beträchtlich höheren Wandtemperatur oder mit dem Eintreten der Siedekrise. Als Ursache für dieses Phänomen wurde die Ablagerung von im Argon gelöstem CO2 an der Heizfläche ermittelt, wobei zu beachten ist, daß die Reinheit des verwendeten Argons größer als 99,996 vol-% war. In weiteren Versuchen wurde der Einfluß der CO2-Konzentration auf diesen Fouling-Vorgang bestimmt und ein Verfahren entwickelt, um das CO2 aus dem Meßkreislauf zu entfernen. Der Ablagerungsmechanimus und der Einfluß der Betriebsparameter auf die Ablagerungsgeschwindigkeit können mit Modellvorstellungen zur Blasenbildung erklärt werden.
Fouling-phenomena during the evaporation of argon within a horizontal tube
During heat transfer measurements at flow boiling of argon a transient increase of the wall temperature has been observed, though the parameters such as heat flux, mass velocity, flow quality and system pressure were kept constant. This temperature drifting ended after several hours at a considerably higher wall temperature or with the boiling crisis. Although the purity of the test substance was higher than 99.996 vol-%, this phenomenon was caused by the solidification of CO2 on the heating surface. Further investigations showed the influence of the CO2-concentration on the drifting as well as a method to remove the CO2 out of the test fluid. Both, fouling mechanism and influence of the parameters on the fouling, can be explained satisfactorily by means of bubble-growth mechanisms.相似文献
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