Die Wirkung von Strahlen auf Acetabularia

1956 ◽  
Vol 11 (8) ◽  
pp. 463-470 ◽  
Author(s):  
Erich Six
Keyword(s):  
Uv Absorption ◽  
Biologische Wirksamkeit

Es wurde die Einwirkung monochromatischer ultravioletter Strahlen der Wellenlänge 254 mμ, 281 mμ und 297 mμ auf kernlose Zellteile von Acetabularia untersucht. Dazu wurden in Abhängigkeit von der Strahlendosis die mittlere Lebensdauer und das Formbildungs-Vermögen der kernlosen Teile bestimmt. Der 254-mμ-Strahlung kam dabei stets die größte biologische Wirksamkeit zu, während die 297-mμ-Strahlung im untersuchten Dosisbereich fast ohne Wirkung blieb. Die gefundene Wellenlängen-Abhängigkeit weist darauf hin, daß der UV-Absorption durch die Purine und Pyrimidine für den Wirkungsmechanismus der beobachteten UV-Schädigungen kernloser Zellteile besondere Bedeutung zukommen muß.

UV Absorption and Photoisomerization of p-Methoxycinnamate Grafted Silicone

2004 ◽  
Author(s):  
Supason Pattanaargson ◽  
Nantawan Hongchinnagorn ◽  
Piyawan Hirunsupachot ◽  
Yongsak Sritana-anant
Keyword(s):  
Uv Absorption

Variational Method for Estimating the Dipole Moment in the Second Excited State of Fluorescein Molecule from its Electronic UV Absorption Spectra

2019 ◽  
Vol 70 (10) ◽  
pp. 3538-3544
Author(s):  
Alina Costina Luca ◽  
Ana Cezarina Morosanu ◽  
Irina Macovei ◽  
Dan Gheorghe Dimitriu ◽  
Dana Ortansa Dorohoi ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Variational Method ◽  
Electronic State ◽  
Excited Electronic State ◽  
Spectral Band ◽  
Uv Absorption ◽  
Optical Parameters ◽  
Electrical Permittivity ◽  
Fluorescein Molecule

Electro-optical parameters of fluorescein molecule in the second excited electronic state and information on the interactions with solvents were obtained from a solvatochromic study. Parameters of the solvents such as the refractive index, electrical permittivity and Kamlet-Taft parameters (hydrogen bond acidity and basicity) were related with the experimentally recorded shifts of UV absorption spectral band of fluorescein dissolved in several solvents. Through a variational method, the electric dipole moment and polarizability in excited state of fluorescein molecule were estimated. The calculus requires some parameters of the fluorescein molecule in the ground electronic state, which were determined through a quantum-mechanical study.

Development of a monitor to simultaneously measure dissolved ozone and organic matter in ozonated water

1998 ◽  
Vol 37 (12) ◽  
pp. 285-292 ◽  
Author(s):  
Hiroshi Tsugura ◽  
Tetufumi Watanabe ◽  
Hiroshi Shimazaki ◽  
Shoichi Sameshima
Keyword(s):  
Organic Matter ◽  
Control System ◽  
Sodium Thiosulfate ◽  
Experimental Results ◽  
Uv Absorption ◽  
Uv Absorbance ◽  
Absorption Method ◽  
Ozonated Water

A method for measuring both dissolved ozone (DO3) concentration and UV absorbance was developed adopting ultraviolet (UV) absorption method (JWWA, 1993) using sodium thiosulfate (Na2S2O3) solution for removing residual ozone in ozonated water. A DO3 monitor based on this method was tested. This method was proven to be effective from experimental results. The performance of the monitor was examined with continuous ozonated water. As a result, the monitor performed stably during about 2 months, so that both DO3 concentration and UV absorbance in the ozonated water could be accurately measured. Therefore, the authors have proposed the new aquatic control system with this monitor for ozonation.

Simulation of UV Absorption Spectra and Relaxation Dynamics of Uracil and Uracil-Water Clusters

2020 ◽  
Author(s):  
Branislav Milovanović ◽  
Jurica Novak ◽  
Mihajlo Etinski ◽  
Wolfgang Domcke ◽  
Nadja Doslic
Keyword(s):  
Aqueous Solution ◽  
Gas Phase ◽  
Absorption Spectra ◽  
Absorption Spectroscopy ◽  
Water Clusters ◽  
Uv Absorption ◽  
Relaxation Dynamics ◽  
Nonradiative Relaxation ◽  
Uv Absorption Spectra ◽  
Uv Absorption Spectroscopy

Despite many studies, the mechanisms of nonradiative relaxation of uracil in the gas phase and in aqueous solution are still not fully resolved. Here we combine theoretical UV absorption spectroscopy...

scholarly journals Enhanced ultraviolet absorption in graphene by aluminum and magnesium hole-arrays

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xueling Cheng ◽  
Yunshan Wang
Keyword(s):  
Numerical Study ◽  
Uv Spectroscopy ◽  
Single Layer ◽  
Hybrid Structure ◽  
Uv Absorption ◽  
Single Layer Graphene ◽  
Visible Range ◽  
Uv Spectrum ◽  
Hole Arrays ◽  
Uv Range

AbstractOptoelectronic devices in the UV range have many applications including deep-UV communications, UV photodetectors, UV spectroscopy, etc. Graphene has unique exciton resonances, that have demonstrated large photosensitivity across the UV spectrum. Enhancing UV absorption in graphene has the potential to boost the performance of the various opto-electronic devices. Here we report numerical study of UV absorption in graphene on aluminum and magnesium hole-arrays. The absorption in a single-layer graphene on aluminum and magnesium hole-arrays reached a maximum value of 28% and 30% respectively, and the absorption peak is tunable from the UV to the visible range. The proposed graphene hybrid structure does not require graphene to be sandwiched between different material layers and thus is easy to fabricate and allows graphene to interact with its surroundings.

scholarly journals Ultraviolet Absorption Cross-Sections of Ammonia at Elevated Temperatures for Nonintrusive Quantitative Detection in Combustion Environments

2021 ◽  
pp. 000370282199044
Author(s):  
Wubin Weng ◽  
Shen Li ◽  
Marcus Aldén ◽  
Zhongshan Li
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Absorption Cross Section ◽  
Elevated Temperatures ◽  
Uv Absorption ◽  
Energy Utilization ◽  
Quantitative Detection ◽  
Absorption Cross ◽  
Hot Gas

Ammonia (NH3) is regarded as an important nitrogen oxides (NOx) precursor and also as an effective reductant for NOx removal in energy utilization through combustion, and it has recently become an attractive non-carbon alternative fuel. To have a better understanding of thermochemical properties of NH3, accurate in situ detection of NH3 in high temperature environments is desirable. Ultraviolet (UV) absorption spectroscopy is a feasible technique. To achieve quantitative measurements, spectrally resolved UV absorption cross-sections of NH3 in hot gas environments at different temperatures from 295 K to 590 K were experimentally measured for the first time. Based on the experimental results, vibrational constants of NH3 were determined and used for the calculation of the absorption cross-section of NH3 at high temperatures above 590 K using the PGOPHER software. The investigated UV spectra covered the range of wavelengths from 190 nm to 230 nm, where spectral structures of the [Formula: see text] transition of NH3 in the umbrella bending mode, v2, were recognized. The absorption cross-section was found to decrease at higher temperatures. For example, the absorption cross-section peak of the (6, 0) vibrational band of NH3 decreases from ∼2 × 10−17 to ∼0.5 × 10−17 cm2/molecule with the increase of temperature from 295 K to 1570 K. Using the obtained absorption cross-section, in situ nonintrusive quantification of NH3 in different hot gas environments was achieved with a detection limit varying from below 10 parts per million (ppm) to around 200 ppm as temperature increased from 295 K to 1570 K. The quantitative measurement was applied to an experimental investigation of NH3 combustion process. The concentrations of NH3 and nitric oxide (NO) in the post flame zone of NH3–methane (CH4)–air premixed flames at different equivalence ratios were measured.

The riddle of the forbidden UV absorption of aqueous nitrate: the oscillator strength of the n → π* transition in NO3− including second order vibronic coupling

2019 ◽  
Vol 21 (42) ◽  
pp. 23466-23472 ◽  
Author(s):  
Pernille D. Pedersen ◽  
Maria Harris Rasmussen ◽  
Kurt V. Mikkelsen ◽  
Matthew S. Johnson
Keyword(s):  
Oscillator Strength ◽  
Vibronic Coupling ◽  
Second Order ◽  
Uv Absorption ◽  
Nitrate Anion ◽  
Simple Scheme

The environmentally relevant n → π* transition in the nitrate anion is doubly forbidden by symmetry. A simple scheme for including second order vibronic coupling is presented.

Improved Polydopamine Deposition in Amine-Functionalized Silica Aerogels for Enhanced UV Absorption

2021 ◽  
Author(s):  
Gabrielle Rey ◽  
Stephanie L. Vivod ◽  
Saranshu Singla ◽  
Theresa Benyo ◽  
Jaelynne King ◽  
...  
Keyword(s):  
Silica Aerogels ◽  
Uv Absorption ◽  
Functionalized Silica ◽  
Amine Functionalized
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