Spectroanalytical Parameters of Fungal Metabolites. IV. Moniliformin

1974 ◽  
Vol 57 (6) ◽  
pp. 1392-1396 ◽  
Author(s):  
J A Lansden ◽  
R J Clarkson ◽  
W C Neely ◽  
R J Cole ◽  
J W Kirksey
Keyword(s):  
Low Temperature ◽  
Aqueous Solutions ◽  
Ambient Temperature ◽  
Emission Spectrum ◽  
Potassium Salt ◽  
Emission Spectra ◽  
Fungal Metabolites ◽  
Fungal Metabolite ◽  
Fluorescence Excitation ◽  
Phosphorescence Emission

Abstract The spectral data for a novel fungal metabolite, moniliformin (potassium salt of 1-hydroxycyclobut- 1-ene-3,4-dione), are reported. The corrected ambient temperature fluorescence excitation and emission spectra are given and the quantum efficiency is calculated to be 5.32 × 10舓3. The uncorrected low temperature phosphorescence emission spectrum and lifetime are also reported. Other physical data are given to support spectral evidence that the molecule exists as a dimer in aqueous solutions.

Spectroanalytical Parameters of Fungal Metabolites. II. Luminescence of Griseofulvin

1972 ◽  
Vol 55 (6) ◽  
pp. 1300-1304
Author(s):  
W C Neely ◽  
J R Mcduffie
Keyword(s):  
Thin Layer ◽  
Fluorescence Lifetime ◽  
Light Exposure ◽  
Emission Spectra ◽  
Fungal Metabolites ◽  
Fluorescence Excitation ◽  
Phosphorescence Lifetime ◽  
Phosphorescence Emission ◽  
The Mean ◽  
Luminescence Characteristics

Abstract I n this study of the luminescence characteristics of griseofulvin we report corrected ambient temperature fluorescence excitation and emission spectra. The uncorrected fluorescence excitation and emission spectra on thin layer chromatographic plates are also reported. The quantum efficiency of fluorescence is calculated to be 0.108 and the mean phosphorescence lifetime determined to be 0.11 sec. The fluorescence lifetime is calculated to be 0.663 nsec. It appears t h a t phosphorescence emission may be the most sensitive spectral parameter; measurable phosphorescence can be obtained from solutions as dilute as 10-8M. No photodecomposition is apparent under reasonable conditions of light exposure.

A fluorescent probe based on N-doped carbon dots for highly sensitive detection of Hg2+ in aqueous solutions

2016 ◽  
Vol 8 (10) ◽  
pp. 2297-2304 ◽  
Author(s):  
Zhi-hao Gao ◽  
Zheng-zhong Lin ◽  
Xiao-mei Chen ◽  
Hui-ping Zhong ◽  
Zhi-yong Huang
Keyword(s):  
Absorption Spectrum ◽  
Aqueous Solutions ◽  
Fluorescent Probe ◽  
Carbon Dots ◽  
Emission Spectra ◽  
Sensitive Detection ◽  
Fluorescence Excitation ◽  
Highly Sensitive ◽  
Highly Sensitive Detection ◽  
Doped Carbon Dots

The UV-Vis absorption spectrum (left) and fluorescence excitation and emission spectra (right) of NCDs.

INTERFERENCE OF THE FERMI EDGE SINGULARITY WITH AN EXCITONIC RESONANCE IN DOPED SEMICONDUCTORS

1991 ◽  
Vol 05 (02) ◽  
pp. 135-138 ◽  
Author(s):  
JOACHIM F. MUELLER ◽  
ANDREI E. RUCKENSTEIN ◽  
STEFAN SCHMITT-RINK
Keyword(s):  
Low Temperature ◽  
Fermi Surface ◽  
Fermi Level ◽  
Emission Spectrum ◽  
Emission Spectra ◽  
Doped Semiconductors ◽  
Edge Singularity ◽  
Fermi Edge ◽  
Fermi Edge Singularity ◽  
Excitonic Resonance

Low-temperature emission spectra are calculated for an n-doped semiconductor in which the Fermi level is almost degenerate with an exciton of a higher conduction band. It is shown that in such a sample the virtual transitions of electrons from the Fermi surface into the excitonic state can lead to a strong enhancement of the optical oscillator strength. In particular, due to this effect, the Fermi edge singularity, which is usually only seen in absorption, can become visible also in the emission spectrum. This explains the optical spectra recently obtained in experiments on modulation-doped heterostructures.

A Green and Energy-efficient Photocatalytic Process for accelerated synthesis of Lactic Acid Esters using functionalized quantum dots

2021 ◽  
Author(s):  
Priyanka Verma ◽  
Ravinder Kumar Wanchoo ◽  
Amrit Pal Toor
Keyword(s):  
Quantum Dots ◽  
Lactic Acid ◽  
Low Temperature ◽  
Ambient Temperature ◽  
Energy Efficient ◽  
Photocatalytic Process ◽  
Photochemical Process ◽  
Line P ◽  
Safe Approach ◽  
Acid Esters

Sulphonate-grafted-Titania (SO3H-TiO2) quantum dot catalyzed photochemical process offered an energy-efficient, accelerated, and safe approach to synthesize lactic acid esters at ambient temperature conditions. This low-temperature route is conceived in line...

Investigation of High Percentage Acetone-Butanol-Ethanol (ABE) Blended With Diesel in a Constant Volume Chamber

2014 ◽  
Author(s):  
Yilu Lin ◽  
Han Wu ◽  
Karthik Nithyanandan ◽  
Timothy H. Lee ◽  
Chia-fon F. Lee ◽  
...  
Keyword(s):  
Low Temperature ◽  
Ambient Temperature ◽  
Constant Volume ◽  
Low Temperature Combustion ◽  
Transportation Fuel ◽  
Promising Alternative ◽  
Alternative Transportation ◽  
Constant Volume Chamber ◽  
Temperature Combustion ◽  
Acetone Butanol Ethanol

Bio-butanol, a promising alternative transportation fuel, has its industrial-scale production hindered significantly by high cost component purification process from acetone-butanol-ethanol (ABE) broth. The purpose of this study is to investigate the possibility of using ABE-Diesel blends with high ABE percentages as an alternative transportation fuel. An optical-accessible constant volume chamber capable of controlling ambient temperature, pressure and oxygen concentration was used to mimic the environmental conditions inside a real diesel engine cylinder. ABE fuel with typical volumetric ratios of 30% acetone, 60% butanol and 10% ethanol were blended with ultra-low sulfur diesel at 80% vol. and were tested in this study. The ambient temperature was set to be at 1100K and 900K, which represents normal combustion conditions and low temperature combustion conditions respectively. The ambient oxygen concentrations were set to be at 21%, 16% and 11%, representing different EGR ratios. The in-cylinder pressure was recorded by using a pressure transducer and the time-resolved Mie-scattering image and natural flame luminosity was captured using a high-speed camera coupled with a copper vapor laser. The results show that the liquid penetration is reduced by the high percentage of ABE in the blends. At the same time, the soot formation is reduced significantly by increasing oxygen content in the ABE fuel. Even more interesting, a soot-free combustion was achieved by combining the low temperature combustion with the higher percentage ABE case. In terms of soot emission, high ABE ratio blends are a very promising alternative fuel to be directly used in diesel engines especially under low-temperature combustion conditions.

Recovery in 15%Cr Ferritic Stainless Steel after Large Strain Deformation

2007 ◽  
Vol 558-559 ◽  
pp. 119-124
Author(s):  
Andrey Belyakov ◽  
Kaneaki Tsuzaki ◽  
Yoshisato Kimura ◽  
Yoshinao Mishima
Keyword(s):  
Stainless Steel ◽  
Low Temperature ◽  
Dislocation Density ◽  
Ambient Temperature ◽  
Ferritic Stainless Steel ◽  
Vickers Hardness ◽  
Subgrain Size ◽  
Large Strain ◽  
Internal Stresses ◽  
Cumulative Strain

15%Cr ferritic stainless steel was machined in rectangular samples and then processed by multiple forging to a total cumulative strain of 7.2 at an ambient temperature. The large strain deformation resulted in almost equiaxed submicrocrystalline structure with a mean grain/subgrain size of 230 nm and about 2.2×1014 m-2 dislocation density in grain/subgrain interiors. The annealing at a relatively low temperature of 500oC did not lead to any discontinuous recrystallizations. The grain/subgrain size and the interior dislocation density slightly changed to 240 nm and 2.1×1014 m-2, respectively, after annealing for 30 min, while the Vickers hardness decreased from 3140 MPa in the as-processed state to 2900 MPa. This annealing softening was attributed to remarkable release (by 50%) of internal stresses, which are associated with a non-equilibrium character of strain-induced grain/subgrain boundaries.

scholarly journals Low temperature dielectric relaxation study of aqueous solutions of diethylsulfoxide

2014 ◽  
Vol 129 (11) ◽  
Author(s):  
Liana Gabrielyan ◽  
Shiraz Markarian ◽  
Peter Lunkenheimer ◽  
Alois Loidl
Keyword(s):  
Low Temperature ◽  
Aqueous Solutions ◽  
Dielectric Relaxation ◽  
Relaxation Study

The photochemical reactivity of some benzoylthiophenes. IV. The effect of an adjacent methyl group on the excited state reactivity of 3-benzoylthiophene

1978 ◽  
Vol 56 (15) ◽  
pp. 1970-1984 ◽  
Author(s):  
D. R. Arnold ◽  
C. P. Hadjiantoniou
Keyword(s):  
Hydrogen Abstraction ◽  
Thiophene Ring ◽  
Emission Spectra ◽  
Photochemical Reactions ◽  
Triplet States ◽  
Photochemical Reactivity ◽  
Methyl Group ◽  
State Diagrams ◽  
Phosphorescence Emission ◽  
Intramolecular Hydrogen

The electronic absorption and phosphorescence emission spectra and the photochemical reactivity of several methyl-3-benzoylthiophenes (2- and 4-methyl-3-benzoylthiophene (1, 2), 2,5-dimethyl-3-benzoylthiophene (3), and 3-(2-methylbenzoyl)thiophene (4)) have been studied. Partial state diagrams have been constructed. The lowest energy absorption in hexane solution in every case is the carbonyl n → π* transition. The two lowest triplet states of these ketones are close in energy and, in fact, the nature of the emitting triplet (n,π* or π,π*) depends upon the position of methyl substitution and upon the solvent. The photochemical reactions studied include intramolecular hydrogen abstraction (revealed by deuterium exchange in the adjacent methyl group upon irradiation in perdeuteriomethanol solution), photocycloaddition of dimethyl acetylenedicarboxylate to the thiophene ring, and photocycloaddition of isobutylene to the carbonyl group. Generalizations, potentially useful for predicting photochemical reactivity of these and other aromatic ketones are summarized.

Searching for 3D effects in the optical, high spectral resolution emission spectrum of KELT-9b

2021 ◽  
Author(s):  
Lorenzo Pino ◽  
Matteo Brogi ◽  
Jean-Michel Désert ◽  
Emily Rauscher
Keyword(s):  
Emission Spectrum ◽  
Spectral Resolution ◽  
Planet Formation ◽  
Emission Spectra ◽  
Optical Emission ◽  
High Spectral Resolution ◽  
Optical Emission Spectrum ◽  
Hot Jupiters ◽  
Atmospheric Structure ◽  
3D Effects

<p>Ultra-hot Jupiters (UHJs; T<sub>eq</sub> ≥ 2500 K) are the hottest gaseous giants known. They emerged as ideal laboratories to test theories of atmospheric structure and its link to planet formation. Indeed, because of their high temperatures, (1) they likely host atmospheres in chemical equilibrium and (2) clouds do not form in their day-side. Their continuum, which can be measured with space-facilities, can be mostly attributed to H- opacity, an indicator of metallicity. From the ground, the high spectral resolution emission spectra of UHJs contains thousands of lines of refractory (Fe, Ti, TiO, …) and volatile species (OH, CO, …), whose combined atmospheric abundances could track planet formation history in a unique way. In this talk, we take a deeper look to the optical emission spectrum of KELT-9b covering planetary phases 0.25 - 0.75 (i.e. between secondary eclipse and quadrature), and search for the effect of atmospheric dynamics and three-dimensionality of the planet atmosphere on the resolved line profiles, in the context of a consolidated statistical framework. We discuss the suitability of the traditionally adopted 1D models to interprete phase-resolved observations of ultra-hot Jupiters, and the potential of this kind of observations to probe their 3D atmospheric structure and dynamics. Ultimately, understanding which factors affect the line-shape in UHJs will also lead to more accurate and more precise abundance measurements, opening a new window on exoplanet formation and evolution.</p>

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