Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 110 for “"Quantum Yields"”.
-
Quantum Yields And Mechanism In Titanium Dioxide Mediated Photocatalysis
… to be 0.28 {dollar}pm{dollar} 0.03.;A method for quantum yield determinations in heterogeneous systems was developed, based on the measurements of {dollar}cdot{dollar}OH radical generation rates and the flux of absorbed photons by TiO{dollar}sb2{dollar} suspensions. In this procedure a modified …
-
Satellite-derived fluorescence quantum yields as indicators of phytoplankton photophysiology
… however, remote sensing-derived fluorescence quantum yields have the potential for monitoring phytoplankton photophysiological states on a global scale. Recent research has demonstrated the effects of both nutrient stress and photoacclimation on fluorescence yield. Here, a novel satellite …
-
Method For Determination Of Singlet Oxygen Quantum Yields For New Fluorene-based Photosensitizers In Aqueous Media For The Advancement Of Photodynamic Therapy
… tissue. The measurement of the singlet oxygen quantum yield is an important determinant used to evaluate the efficiency of new photodynamic therapy agents developed in the laboratory, to screen potential photosensitizers in aqueous media.The singlet oxygen quantum yield is a quantitative …
-
The Photophysics and Photochemistry of a series of Phthalocyanines as Potential Photosensitisers in Photodynamic Therapy
… in the red, low fluorescence and high triplet quantum yields that make it an ideal candidate as a potential photosensitiser in photodynamic therapy. Photodynamic therapy is an alternative treatment to cancer using a photosensitiser, which is preferentially absorbed by malignant cells and …
-
Direct Chemiluminescence From Secondary Peresters
… decomposition of the peresters was studied. The quantum yield of chemiluminescence was very low in all cases, and seemed to vary inversely with the strength of the alpha carbon-hydrogen bond. The peresters were generated using two methods: reaction of the acid chloride of 1, 19, with the …
-
Light utilization and excretion of organic matter by antarctic lake phytoplankton
Quantum yields (φ) were determined for the phytoplankton of four perennially ice-covered lakes of southern Victoria Land, Antarctica. The phytoplankton communities of these oligotrophic lakes are dominated by cryptophytes, unicellular chrysophytes and flagellated chlorophytes. Quantum yields were …
-
ΣΥΝΘΕΣΗ ΚΑΙ ΧΗΜΕΙΟΦΩΤΑΥΓΕΙΑ ΔΙΥΠΟΚΑΤΕΣΤΗΜΕΝΩΝ ΣΤΙΛΒΕΝΙΩΝ
… STILBENES WAS ACCOMPLISHED IN GOOD YIELDS BY THE WITTIG CARBONYL OLEFINATION REACTION. THE OZONOLYSIS OF THESE STILBENOLS WAS FOUND TO BE CHEMILUMINESCENT, THE QUANTUM YIELDS (1,2X10-4 - 8,1X10-6) DEPENDING ON HAMMETT'S "6" CONSTANT FOR THE 4'- SUBSTITUENT, AND SALICYLALDEHYDE ANION …
-
Structure-property studies of conjugated 1,8-naphthalic anhydrides
… of the system. Both series showed a range of quantum yields, intramolecular charge-transfer properties, good electron-accepting character, and good chemical stability. The properties of the two series were compared to one another. Fluorescence quantum yields were much higher in the 4-series …
-
Fluorescent silicon nanocrystals for bioimaging
Quantum dots have been used as alternatives to organic dyes for fluorescence imaging because they are resistant to photobleaching, exhibit strong response to two-photon excitation, and can be conjugated to a wide variety of targeting molecules. Silicon (Si) nanocrystal quantum dots in particular …
-
Synthesis of Fluorescent Molecules and their Applications as Viscosity Sensors, Metal Ion Indicators, and Near-Infrared Probes
… in a viscous environment. Values of fluorescence quantum yields in 99% glycerol/1% methanol (v/v) of varying temperature from 293 K to 343 K, together with fluorescence quantum yields, radiative and nonradiative rate constants and fluorescence lifetimes in glycerol/methanol solutions of varying …
-
Photophysical characterization of toluene and 3 pentanone for quantitative imaging of fuel/air ratio and temperature in combustion systems
… work, absorption cross-sections, fluorescence quantum yields and oxygen quenching efficiencies of toluene-LIF were investigated in a heated flow cell (300 - 900 K) and absolute fluorescence quantum yields of 3-pentanone in dependence on excitation wavelength have been determined. A …
-
STUDIES ON THE ANALYSIS AND THE FATE OF ORGANIC POLLUTANTS IN THE ENVIRONMENT
… The photolysis rates and the photodegradation quantum yields of 16 organophosphorus esters were determined at the wavelength of 254 nm and 313 nm. The effects of molecular structure on the photolysis rates of the organophosphorus pesticides were investigated by using a series of compounds with …
-
Lanthanide luminescence in Pybox functionalized metallopolymers
… polymers results in luminescent solids with high quantum efficiencies. Two Pybox monomers were synthesized and studied in detail. These monomers were copolymerized with three co-monomers through either radical polymerization in one case or through ring opening metathesis polymerization in the …
-
Synthesis Of Alkylthiol-containing Fluorene Derivatives For Gold Nanoparticle Functionalization
… of gold nanoparticles on the singlet oxygen quantum yields of fluorene dyes that already exhibit high singlet oxygen quantum yields as well as high two photon absorption (2PA) cross-sections. The dialkylation of the fluorene derivatives was accomplished by reacting the dye with [alpha], …
-
Forster Resonance Energy Transfer in materials used in Luminescent Solar Concentrators
… on the choice of fluorescent material: Non-unity quantum yield and reabsorption of the emitted fluorescence. Organic dyes have high quantum yields but suffer from reabsorption due to a large spectral overlap between the absorption and emission profiles. Semiconductor nanoparticles have little or …
-
The mechanism of an unusual benzo/benzo photocycloaddition reaction : photophysical and photochemical investigation of [3.3] orthocyclophanes with two face-to-face preoriented benzenoid chromophores
… fluorescence emission, excitation, lifetimes, quantum yields; phosphorescence - and photochemical properties - photoreaction quantum yields, triplet sensitization - have been investigated. The analysis of the data allowed the formulation of kinetic models and potential energy surface (= PES) …
-
The Synthesis and Evaluation of Non-Targeted Near-Infrared Heptamethine Molecular Probes
… and emission wavelengths, fluorescence quantum yields and Stokes shifts. It is noted that most dyes synthesised within this thesis, show comparable Stokes shift but increased fluorescence quantum yields when compared against ICG and IR-820. All dyes absorb and emit within the NIR region …
-
A NEW CLASS OF LUMINESCENT ORGANOMETALLICS -DIETHYNYLRHODACYCLOPENTADIENES
… gave the highest fluorescence quantum yields compared to the other series of rhodacyclopentadienes. Extended phenylene-ethynylene ligands (i.e. DHAPEPE-) did not impart any effects on the max values in absorption and emission but the quantum yields were lower than those for the …
-
Photophysics and photochemistry of natural waters with emphasis on radical probe development and application
… A decrease in fluorescence lifetime and quantum yield of tens- to hundreds-fold was observed for the paramagnetic compounds relative to their diamagnetic counterparts. Very rapid fluorescence quenching rates (3 to 80 x 1010 s-1) were calculated for the fluorescamine moiety of the …
-
Photochemical and computational study of sulfoxides, sulfenic esters, and sulfinyl radicals
… of dibenzothiophene and oxidized solvent. Though quantum yields are low, chemical yields of the sulfide are quite high. Yields of the oxidized solvents can also be high. Typical products are phenol from benzene, cyclohexanol, and cyclohexene from cyclohexane and 2-cyclohexenol and epoxycyclohexane …
Page 1 of 6