Halogenation of a twisted non-polar π-system as a tool to modulate phosphorescence at room temperature

Temperature dependence of the emission behaviour of benzil has been studied in three imidazolium ionic liquids differing in their polarity and viscosity. Room temperature absorption and steady-state emission spectra suggest that the ground and excited state conformers of benzil in ionic liquids are similar to those in conventional organic solvents. The non-degassed solutions of benzil in ionic liquids show phosphorescence at room temperature in contrast to conventional solvents where phosphorescence is commonly observed in degassed conditions. This study reveals that a thermally activated reverse intersystem crossing (T1↝S1) process is responsible for the drastic change in phosphorescence intensity with temperature in ionic liquids. The rate constant () of this process is found to be dependent on the polarity of the media and is 5 times higher in most polar ionic liquids. The evidence of the presence of multiple conformers of benzil in frozen conditions is obtained from the excitation wavelength dependence of the phosphorescence spectra.

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Electron microscope studies of the plastic deformation of ternary alloys based on GaAs

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100178732 ◽

1990 ◽

Vol 48 (4) ◽

pp. 1120-1120

Author(s):

R. Haswell ◽

U. Bangert ◽

P. Charsley

Keyword(s):

Plastic Deformation ◽

Electron Microscope ◽

Room Temperature ◽

Stacking Faults ◽

The Other ◽

Ternary Alloys ◽

Dislocation Mobility ◽

Semiconducting Materials ◽

Micro Indentation

A knowledge of the behaviour of dislocations in semiconducting materials is essential to the understanding of devices which use them . This work is concerned with dislocations in alloys related to the semiconductor GaAs . Previous work on GaAs has shown that microtwinning occurs on one of the <110> rosette arms after indentation in preference to the other . We have shown that the effect of replacing some of the Ga atoms by Al results in microtwinning in both of the rosette arms.In the work to be reported dislocations in specimens of different compositions of Gax Al(1-x) As and Gax In(1-x) As have been studied by using micro indentation on a (001) face at room temperature . A range of electron microscope techniques have been used to investigate the type of dislocations and stacking faults/microtwins in the rosette arms , which are parallel to the [110] and [10] , as a function of composition for both alloys . Under certain conditions microtwinning occurs in both directions . This will be discussed in terms of the dislocation mobility.

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HAYNES STELLITE ALLOY No. 98M2

Alloy Digest ◽

10.31399/asm.ad.co0022 ◽

1960 ◽

Vol 9 (7) ◽

Keyword(s):

Fracture Toughness ◽

Compressive Strength ◽

Physical Properties ◽

Room Temperature ◽

Base Alloy ◽

Heat Treating ◽

The Other ◽

Stellite Alloy ◽

Cobalt Base Alloy ◽

Cobalt Base

Abstract HAYNES STELLITE 98M2 Alloy is a cobalt-base alloy having higher compressive strength and higher hardness than all the other cobalt-base alloys at room temperature and in the red heat range. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness. It also includes information on heat treating, machining, and joining. Filing Code: Co-22. Producer or source: Haynes Stellite Company.

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Mass spectrometric study of allyl radical, allyl bromide and 1,5-hexadiene interactions with oxides; Cobalt suboxide Co3O4

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19792009 ◽

1979 ◽

Vol 44 (7) ◽

pp. 2009-2014 ◽

Cited By ~ 2

Author(s):

Jana Nováková ◽

Zdeněk Dolejšek

Keyword(s):

Room Temperature ◽

Allyl Bromide ◽

Catalytic Properties ◽

Mass Spectrometric Study ◽

Spectrometric Study ◽

Flow Conditions ◽

Allyl Radical ◽

Knudsen Flow ◽

Thermally Activated ◽

Radical Interaction

Products of (a) allyl radical interaction with unheated Co3O4, (b) thermally activated 1,5-hexadiene or thermally activated allyl bromide with unheated Co3O4, (c) moderately heated Co3O4 with unheated 1,5-hexadiene or allyl bromide were studied under Knudsen flow conditions. Cobalt suboxide Co3O4, a typical catalyst of deep oxidations yielded acrolein in reaction with allyl radicals as early as at the room temperature of the catalyst. A similar acrolein formation was also observed in the allyl radical interaction with other oxides exhibiting different catalytic properties. It appears that acrolein is in general the primary product of the allyl radical interaction with the oxides. The results are discussed and compared with previous data obtained with MoO3.

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The Reactivity of Different Active Forms of Sodium Carbonate with Respect to Sulfur Dioxide

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19922302 ◽

1992 ◽

Vol 57 (11) ◽

pp. 2302-2308

Author(s):

Karel Mocek ◽

Erich Lippert ◽

Emerich Erdös

Keyword(s):

Thermal Decomposition ◽

Liquid Phase ◽

Sulfur Dioxide ◽

Specific Surface ◽

Surface Area ◽

Sodium Carbonate ◽

Room Temperature ◽

Active Form ◽

The Other ◽

Kinetics Of

The kinetics of the reaction of solid sodium carbonate with sulfur dioxide depends on the microstructure of the solid, which in turn is affected by the way and conditions of its preparation. The active form, analogous to that obtained by thermal decomposition of NaHCO3, emerges from the dehydration of Na2CO3 . 10 H2O in a vacuum or its weathering in air at room temperature. The two active forms are porous and have approximately the same specific surface area. Partial hydration of the active Na2CO3 in air at room temperature followed by thermal dehydration does not bring about a significant decrease in reactivity. On the other hand, if the preparation of anhydrous Na2CO3 involves, partly or completely, the liquid phase, the reactivity of the product is substantially lower.

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Room Temperature Phosphorescence vs Triplet–Triplet Annihilation in N-Substituted Acridone Solids

The Journal of Physical Chemistry Letters ◽

10.1021/acs.jpclett.1c01552 ◽

2021 ◽

pp. 6431-6438

Author(s):

Ehsan Hamzehpoor ◽

Cory Ruchlin ◽

Yuze Tao ◽

Jorge Eduardo Ramos-Sanchez ◽

Hatem M. Titi ◽

...

Keyword(s):

Room Temperature ◽

Room Temperature Phosphorescence ◽

Triplet Triplet Annihilation

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Structure and Conductivity of Iodine-Doped C60 Thin Films

MRS Proceedings ◽

10.1557/proc-359-443 ◽

1994 ◽

Vol 359 ◽

Cited By ~ 1

Author(s):

Jun Chen ◽

Haiyan Zhang ◽

Baoqiong Chen ◽

Shaoqi Peng ◽

Ning Ke ◽

...

Keyword(s):

Thin Films ◽

Electrical Conductivity ◽

Room Temperature ◽

Conductivity Measurements ◽

X Ray Diffraction ◽

Temperature Conductivity ◽

Room Temperature Conductivity ◽

X Ray ◽

Thermally Activated ◽

Order Of Magnitude

ABSTRACTWe report here the results of our study on the properties of iodine-doped C60 thin films by IR and optical absorption, X-ray diffraction, and electrical conductivity measurements. The results show that there is no apparent structural change in the iodine-doped samples at room temperature in comparison with that of the undoped films. However, in the electrical conductivity measurements, an increase of more that one order of magnitude in the room temperature conductivity has been observed in the iodine-doped samples. In addition, while the conductivity of the undoped films shows thermally activated temperature dependence, the conductivity of the iodine-doped films was found to be constant over a fairly wide temperature range (from 20°C to 70°C) exhibiting a metallic feature.

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Synthesis of spiro[dihydropyridine-oxindoles] via three-component reaction of arylamine, isatin and cyclopentane-1,3-dione

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.9.2 ◽

2013 ◽

Vol 9 ◽

pp. 8-14 ◽

Cited By ~ 28

Author(s):

Yan Sun ◽

Jing Sun ◽

Chao-Guo Yan

Keyword(s):

Acetic Acid ◽

Reaction Mechanism ◽

Room Temperature ◽

The Other ◽

Other Hand ◽

Three Component Reaction ◽

High Yields

A fast and convenient protocol for the synthesis of novel spiro[dihydropyridine-oxindole] derivatives in satisfactory yields was developed by the three-component reactions of arylamine, isatin and cyclopentane-1,3-dione in acetic acid at room temperature. On the other hand the condensation of isatin with two equivalents of cyclopentane-1,3-dione gave 3,3-bis(2-hydroxy-5-oxo-cyclopent-1-enyl)oxindole in high yields. The reaction mechanism and substrate scope of this novel reaction is briefly discussed.

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On the Chemistry of Tetrabenzyl Thiuram Disulfide and Tetramethyl Thiuram Disulfide with Bis (Triethoxysilylpropyl) Tetrasulfide in Silica Compounds

Rubber Chemistry and Technology ◽

10.5254/1.3547778 ◽

2003 ◽

Vol 76 (4) ◽

pp. 876-891 ◽

Cited By ~ 1

Author(s):

R. N. Datta ◽

A. G. Talma ◽

S. Datta ◽

P. G. J. Nieuwenhuis ◽

W. J. Nijenhuis ◽

...

Keyword(s):

High Performance ◽

Room Temperature ◽

Succinic Anhydride ◽

Dynamic Properties ◽

The Other ◽

Resonance Spectroscopy ◽

Reaction Products ◽

Negative Effect ◽

Higher Temperature ◽

Analytical Tools

Abstract The use of thiurams such as Tetramethyl thiuram disulfide (TMTD) or Tetrabenzyl thiuram disulfide (TBzTD) has been explored to achieve higher cure efficiency. The studies suggest that a clear difference exists between the effect of TMTD versus TBzTD. TMTD reacts with Bis (triethoxysilylpropyl) tetrasulfide (TESPT) and this reaction can take place even at room temperature. On the other hand, the reaction of TBzTD with TESPT is slow and takes place only at higher temperature. High Performance Liquid Chromatography (HPLC) with mass (MS) detection, Nuclear Magnetic Resonance Spectroscopy (NMR) and other analytical tools have been used to understand the differences between the reaction of TMTD and TESPT versus TBzTD and TESPT. The reaction products originating from these reactions are also identified. These studies indicate that unlike TMTD, TBzTD improves the cure efficiency allowing faster cure without significant effect on processing characteristics as well as dynamic properties. The loading of TESPT is reduced in a typical Green tire compound and the negative effect on viscosity is repaired by addition of anhydrides, such as succinic anhydride, maleic anhydride, etc.

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Recent Observations on the Mechanical Properties of Polymer Networks

Rubber Chemistry and Technology ◽

10.5254/1.3544805 ◽

1971 ◽

Vol 44 (5) ◽

pp. 1256-1272 ◽

Cited By ~ 5

Author(s):

P. Thirion ◽

R. Chasset

Keyword(s):

Crosslink Density ◽

Room Temperature ◽

Dynamic Properties ◽

Polymer Networks ◽

The Other ◽

Dilution Ratio ◽

Chain Entanglement ◽

Influence Of Temperature ◽

Terminal Zone ◽

Crosslinking Agents

Abstract The influence of temperature, elongation, swelling or dilution ratio, crosslink density, nature of the polymers, and crosslinking agents on the dynamic properties, creep and relaxation of polymer networks is surveyed in the terminal region of the spectrum. Whereas the deformation does not change the relaxation kinetics in large ranges of extension, the crosslink density acts as a reduced variable apparently accelerating uniformly the viscoelastic processes beyond the glass transition. The other possible reductions ‘time-temperature’ and ‘time—swelling’ do not necessarily seem related to the variations of free volume. From the viewpoint of the explanation of the relaxation mechanisms in the terminal zone, the fact that the equilibrium of loosely crosslinked elastomers would only virtually be reached after several years at room temperature seem in better agreement with chain entanglement effects, either trapped or not by the permanent network, than with the dissociation of secondary linkages.

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