Hydroxyl Radical Fluorescence and Quantum Yield Following Lyman-α Photoexcitation of Water Vapor in a Room Temperature Cell and Cooled in a Supersonic Expansion

2018 ◽  
Vol 122 (25) ◽  
pp. 5602-5609 ◽  
Author(s):  
Justin W. Young ◽  
Ryan S. Booth ◽  
Kristen M. Vogelhuber ◽  
Jaime A. Stearns ◽  
Christopher J. Annesley
Keyword(s):  
Water Vapor ◽  
Quantum Yield ◽  
Hydroxyl Radical ◽  
Room Temperature ◽  
Supersonic Expansion

Hydration Chamber for Jeolco 200 Kv Microscope

1970 ◽  
Vol 28 ◽  
pp. 542-543
Author(s):  
V. R. Matricardi ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Electron Microscope ◽  
Water Vapor ◽  
Vapor Pressure ◽  
Pressure Gradient ◽  
Room Temperature ◽  
List Type ◽  
Type Number ◽  
Equilibrium Vapor Pressure

In order to observe room temperature hydrated specimens in an electron microscope, the following conditions should be satisfied: The specimen should be surrounded by water vapor as close as possible to the equilibrium vapor pressure corresponding to the temperature of the specimen.The specimen grid should be inserted, focused and photo graphed in the shortest possible time in order to minimize dehydration.The full area of the specimen grid should be visible in order to minimize the number of changes of specimen required.There should be no pressure gradient across the grid so that specimens can be straddled across holes.Leakage of water vapor to the column should be minimized.

Warm and freeze-fracture of cotton seed radicles

1987 ◽  
Vol 45 ◽  
pp. 984-985
Author(s):  
E. L. Vigil ◽  
E. F. Erbe
Keyword(s):  
Thin Film ◽  
Water Vapor ◽  
Fracture Surface ◽  
Membrane Structure ◽  
Room Temperature ◽  
Freeze Fracture ◽  
Longitudinal Axis ◽  
Fracture Plane ◽  
Cotton Seeds ◽  
Condensed Water

In cotton seeds the radicle has 12% moisture content which makes it possible to prepare freeze-fracture replicas without fixation or cryoprotection. For this study we have examined replicas of unfixed radicle tissue fractured at room temperature to obtain data on organelle and membrane structure.Excised radicles from seeds of cotton (Gossyplum hirsutum L. M-8) were fractured at room temperature along the longitudinal axis. The fracture was initiated by spliting the basal end of the excised radicle with a razor. This procedure produced a fracture through the tissue along an unknown fracture plane. The warm fractured radicle halves were placed on a thin film of 100% glycerol on a flat brass cap with fracture surface up. The cap was rapidly plunged into liquid nitrogen and transferred to a freeze- etch unit. The sample was etched for 3 min at -95°C to remove any condensed water vapor and then cooled to -150°C for platinum/carbon evaporation.

Room temperature synthesis of Sn2+ doped highly luminescent CsPbBr3 quantum dots for high CRI white light-emitting diodes

Nanoscale ◽  
2021 ◽  
Author(s):  
Dongdong Yan ◽  
Qionghua Mo ◽  
Shuangyi Zhao ◽  
Wensi Cai ◽  
Zhigang Zang
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
White Light ◽  
Room Temperature ◽  
Temperature Synthesis ◽  
Light Emitting ◽  
Photoluminescence Quantum Yield ◽  
Hot Injection ◽  
White Light Emitting Diodes ◽  
Cspbbr3 Quantum Dots

With a high photoluminescence quantum yield (PLQY) being able to exceed 90% for those prepared by hot injection method, CsPbBr3 quantum dots (QDs) have attracted intensive attentions for white light-emitting...

scholarly journals Enhanced Room‐Temperature Photoluminescence Quantum Yield in Morphology Controlled J‐Aggregates

2021 ◽  
pp. 1903080
Author(s):  
Surendra B. Anantharaman ◽  
Joachim Kohlbrecher ◽  
Gabriele Rainò ◽  
Sergii Yakunin ◽  
Thilo Stöferle ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Room Temperature ◽  
Room Temperature Photoluminescence ◽  
Photoluminescence Quantum Yield ◽  
J Aggregates

scholarly journals Nuclear Spin Symmetry Conservation in 1H216O Investigated by Direct Absorption FTIR Spectroscopy of Water Vapor Cooled Down in Supersonic Expansion

2017 ◽  
Vol 121 (40) ◽  
pp. 7455-7468 ◽  
Author(s):  
Robert Georges ◽  
Xavier Michaut ◽  
Audrey Moudens ◽  
Manuel Goubet ◽  
Olivier Pirali ◽  
...  
Keyword(s):  
Water Vapor ◽  
Ftir Spectroscopy ◽  
Nuclear Spin ◽  
Spin Symmetry ◽  
Direct Absorption ◽  
Supersonic Expansion

scholarly journals Ein Wasserstoffisotopieeffekt im CuSO4 * 5H2O

1969 ◽  
Vol 24 (10) ◽  
pp. 1502-1511
Author(s):  
Karl Heinzinger
Keyword(s):  
Water Vapor ◽  
Aqueous Solutions ◽  
Separation Factor ◽  
Room Temperature ◽  
Copper Ion ◽  
Hydrogen Isotopes ◽  
Bulk Water ◽  
Water Molecules ◽  
Hydration Water ◽  
Sulfate Solutions

Abstract There are two kinds of water in CuSO4·5H2O differing by their binding in the crystal. The oxygen of four water molecules is bonded to the copper ion, that of the fifth molecule is hydrogen bonded. It is shown that the D/H ratios of these two kinds of water differ by 5.7%, the light isotope being enriched in the water molecules coordinated with the copper ion. The results show that there is no exchange of the hydrogen isotopes during the time needed for dehydration at room temperature which takes several days. The assumption has been confirmed that the water coordinated with the copper ion leaves the crystal first on dehydration at temperatures below 50 °C. Additional measurements of the separation factor for the hydrogen isotopes between water vapor and copper sulfate solutions allow conclusions on the fractionation of the hydrogen isotopes between bulk water and hydration water in aqueous solutions.

Characterization of HfO2/Si Exposed to Water Vapor at Room Temperature

2006 ◽  
Vol 917 ◽  
Author(s):  
Carlos Driemeier ◽  
Elizandra Martinazzi ◽  
Israel J. R. Baumvol ◽  
Evgeni Gusev
Keyword(s):  
Water Vapor ◽  
Metal Oxide ◽  
Room Temperature ◽  
Gate Dielectric ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Dielectric Films ◽  
Nuclear Reaction Analysis ◽  
Environmental Air

AbstractHfO2-based materials are the leading candidates to replace SiO2 as the gate dielectric in Si-based metal-oxide-semiconductor filed-effect transistors. The ubiquitous presence of water vapor in the environments to which the dielectric films are exposed (e.g. in environmental air) leads to questions about how water could affect the properties of the dielectric/Si structures. In order to investigate this topic, HfO2/SiO2/Si(001) thin film structures were exposed at room temperature to water vapor isotopically enriched in 2H and 18O followed by quantification and profiling of these nuclides by nuclear reaction analysis. We showed i) the formation of strongly bonded hydroxyls at the HfO2 surface; ii) room temperature migration of oxygen and water-derived oxygenous species through the HfO2 films, indicating that HfO2 is a weak diffusion barrier for these oxidizing species; iii) hydrogenous, water-derived species attachment to the SiO2 interlayer, resulting in detrimental hydrogenous defects therein. Consequences of these results to HfO2-based metal-oxide-semiconductor devices are discussed.

Influences of water vapor on NASICON-based CO2 sensor operative at room temperature

2003 ◽  
Vol 93 (1-3) ◽  
pp. 243-249 ◽  
Author(s):  
Kenji Obata ◽  
Kengo Shimanoe ◽  
Norio Miura ◽  
Noboru Yamazoe
Keyword(s):  
Water Vapor ◽  
Room Temperature ◽  
Co2 Sensor

The photochemical and thermal decompositions of hydrogen sulphide

1953 ◽  
Vol 216 (1126) ◽  
pp. 344-361 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Quantum Yield ◽  
Hydrogen Sulphide ◽  
Low Temperatures ◽  
Room Temperature ◽  
Large Fraction ◽  
Kcal Mole ◽  
Hydrogen Atoms ◽  
Photochemical Decomposition ◽  
Bimolecular Mechanism

The photochemical decomposition of hydrogen sulphide has been investigated at pressures between 8 and 550 mm of mercury and at temperatures between 27 and 650° C, using the narrow cadmium line ( λ 2288) and the broad mercury band (about λ 2550). At room temperature the quantum yield increases with pressure from 1.09 at 30 mm to 1.26 at 200 mm. Above 200 mm pressure there was no further increase in the quantum yield. Temperature had little effect on the quantum yield at λ 2550, but there was a marked increase in the rate of hydrogen production between 500 and 650° C with 2288 Å radiation. This may have been caused by the decomposition of excited hydrosulphide radicals. The results are consistent with a mechanism involving hydrogen atoms and hydrosulphide radicals. The mercury-photosensitized reaction is less efficient than the photochemical decomposition, the quantum yield being only about 0.45. The efficiency increased with temperature and approached unity at high temperatures and pressures. This agrees with the suggestion that a large fraction of the quenching collisions lead to the formation of Hg ( 3 P 0 ) atoms. The thermal decomposition is heterogeneous at low temperatures and becomes homogeneous and of the second order at 650° C. The experimental evidence suggests the bimolecular mechanism 2H 2 S → 2H 2 + S 2 . The activation energies are 25 kcal/mole (heterogeneous) and 50 kcal/mole (homogeneous).

Synthesis and luminescence properties of colloidal lanthanide doped YVO4

2001 ◽  
Vol 667 ◽  
Author(s):  
Arnaud Huignard ◽  
Thierry Gacoin ◽  
Frédéric Chaput ◽  
Jean-Pierre Boilot ◽  
Patrick Aschehoug ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Room Temperature ◽  
Sol Gel ◽  
Precursor Solution ◽  
Silica Matrix ◽  
Luminescence Quantum Yield ◽  
Colloidal Solutions ◽  
Silicon Alkoxide ◽  
Crystalline Defects ◽  
Hydroxylated Surface

ABSTRACTAqueous colloidal solutions of well dispersed YVO4:Ln (Ln = Eu, Nd) nanoparticles are synthesized through precipitation reactions at room temperature. In the case of YVO4:Eu, a luminescence quantum yield of 15% is found, which is not as high as in the bulk due to the existence of residual crystalline defects and nonradiative relaxations from the hydroxylated surface. Appropriate hydrothermal annealing and deuteration of the surface allow to rise the yield up to 38%. Incorporation of the nanocrystals into a transparent silica matrix is achieved through preliminary coating of the particles with a functionnalized silicon alkoxide and further dispersion into a sol-gel precursor solution. Such sol-gel materials doped with YVO4:Nd nanocrystals are transparent and exhibit the typical emission at 1.06 μm of the Nd3+ ion.

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