Abstract. Some kinds of checking methods and principle of dissolved oxygen in water were summarized. Such as: iodometric method, current determination method (Clark dissolved oxygen electrode), conductance measurement and fluorescence quenching. The advantages and disadvantages of each method were compared, and fluorescence quenching was discussed.The method uses Ruthenium complex as fluoresce...

A fluorescent macrocyclic anion receptor based on the 2,6-bis(2-anilinoethynyl)pyridine scaffold has been synthesized to investigate the mechanism of fluorescence quenching in this class of compounds. X-ray crystallography reveals that the binding pocket of the receptor is a natural host to both H2O and HCl, accommodating either molecule in nearly identical environments. Our studies show that p...

Magnetic helicity is nearly conserved and its evolution equation provides a dynamical feedback on the alpha effect that is distinct from the conventional algebraic alpha quenching. The seriousness of this dynamical alpha quenching is particularly evident in the case of closed or periodic boxes. The explicit connection with catastrophic alpha quenching is reviewed and the alleviating effects of ...

We have studied the response of excitons in a multiple quantum well structure under the presence of intense midinfrared fields. Peak fields (∼10 V/cm, in the plane of quantum wells) that would cause exciton quenching at low frequencies (up to ∼ GHz) are observed to have no significant quenching effect on the exciton resonance when applied at ∼100 THz. We attribute this lack of quenching to the ...

A series of 5-dialkyl(aryl)aminomethyl-8-hydroxyquinoline dansylates were synthesized and their fluoroionophoric properties toward representative alkali ions, alkaline earth ions and transition metal ions were investigated. Among the selected ions, Fe3+ caused considerable quenching of the fluorescence, while Cr3+ caused quenching to some extent. The absence of any significant fluorescence quen...

Under excess illumination, plant photosystem II dissipates excess energy through the quenching of chlorophyll fluorescence, a process known as nonphotochemical quenching. Activation of nonphotochemical quenching has been linked to the conversion of a carotenoid with a conjugation length of nine double bonds (violaxanthin) into an 11-double-bond carotenoid (zeaxanthin). It has been suggested tha...

To determine the mechanism of carotenoid-sensitized non-photochemical quenching in cyanobacteria, the kinetics of blue-light-induced quenching and fluorescence spectra were studied in the wild type and mutants of Synechocystis sp. PCC 6803 grown with or without iron. The blue-light-induced quenching was observed in the wild type as well as in mutants lacking PS II or IsiA confirming that neithe...

Inverted membrane vesicles from strain 7, a wild type Escherichia coli K12 strain, actively transport calcium with energy supplied either by respiration or by ATP. These vesicles also have energy-linked quenching of quinacrine fluorescence. Membranes of strain 7, depleted of Mg2+ATPase by EDTA treatment, lack both activities. Membrane vesicles from strain NR70, a mutant lacking the Mg2+ATPase, ...

Quenching of a fluorophore is significantly influenced by the molecular structure of the quencher. In this study, photoluminescence quenching by nitroaromatic compounds was evaluated to assess the molecular interaction between nitroaromatic molecules and the photoluminescent tyrosyl bolaamphiphile self-assembly, a nanoscale optical photoluminescent probe. Both the aromatic structure and hydroph...

We have analyzed the decays of the fluorescence of colloidal CdSe quantum dots (QDs) suspensions during dilution and titration by the ligands. A ligand shell made of a combination of trioctylphosphine (TOP), oleylamine (OA) and stearic acid (SA) stabilizes the as-synthesized QDs. The composition of the shell was analyzed and quantified using high resolution liquid state 1H nuclear magnetic reso...