A New Radiolysis Mechanism for 2′-Deoxyadenosine in Aqueous Deaerated Solution

1979 ◽  
Vol 79 (3) ◽  
pp. 431 ◽  
Author(s):  
N. Mariaggi ◽  
R. Téoule ◽  
J. Cadet ◽  
H. Dickie ◽  
E. Hughes ◽  
...  
Keyword(s):  
Deaerated Solution

The Corrosion Resistance of Hard Anodised EN AW 7075 T6 Alloy

2021 ◽  
Vol 105 (1) ◽  
pp. 329-337
Author(s):  
David Kusmič ◽  
Lenka Klakurková ◽  
Martin Julis ◽  
Pavel Gejdoš ◽  
Jindrich Vilis ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Bulk Material ◽  
Surface Hardness ◽  
Hot Water ◽  
Initial Surface ◽  
Corrosion Properties ◽  
Resistance Surface ◽  
Hard Anodizing ◽  
Deaerated Solution ◽  
7075 Alloy

In this paper, commercially cold-rolled and artificial aged EN AW 7075 T6 alloy has been used. To ensure increased corrosion resistance, surface hardness, scratching resistance, and aesthetic features, this aluminium alloy was subsequently hard anodised and hot-water sealed (AC-A). The hard anodizing and sealing process increased surface hardness up to 304±13 HV 1 from an initial surface hardness of 194±3 HV 1. Also, the microhardness of the anodised layer and bulk material has been documented. Scanning electron microscopy (SEM) was used for microstructure and trapped precipitates investigation in the 42.9±1.4 thick formed anodised layer investigation. The T6 treated (AC) and hard anodised together with sealed (AC-A) EN AW 7075 alloy corrosion properties were evaluated using the anodic potentiodynamic polarisation tests (PPT) in a neutral 2.5% NaCl deaerated solution. The corrosion rate CR (mm/y) decreased approx. 39-times for the hard anodised and sealed EN AW 7075 alloy (AC-A), associated with the shift of the Ecorr (mV) to more positive values, degreased Icorr (µA) and increased Rp (Ohm) values compared to the artificial aged (AC) alloy. Additionally, the pitting was evaluated using laser confocal microscopy, and the pitting coefficient was also calculated.

scholarly journals Hinged and Wide: A New P^P Ligand for Emissive [Cu(P^P)(N^N)][PF6] Complexes

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3934 ◽  
Author(s):  
Sarah Keller ◽  
Matthias Bantle ◽  
Alessandro Prescimone ◽  
Edwin C. Constable ◽  
Catherine E. Housecroft
Keyword(s):  
Mass Spectrometry ◽  
Excited State ◽  
Quantum Yield ◽  
Delayed Fluorescence ◽  
Ionization Mass ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Single Crystal Structures ◽  
Photoluminescence Quantum Yield ◽  
Deaerated Solution

Heteroleptic [Cu(BIPHEP)(N^N)][PF6] complexes (BIPHEP = 1,1′-biphenyl-2,2′-diylbis(diphenylphosphane)), in which N^N is 2,2′-bipyridine (bpy), 6-methyl-2,2′-bipyridine (6-Mebpy), 6-ethyl-2,2′-bipyridine (6-Etbpy), or 5,5′-dimethyl-2,2′-bipyridine (5,5′-Me2bpy), have been synthesized and characterized using multinuclear NMR spectroscopies and electrospray ionization mass spectrometry. The single crystal structures of [Cu(BIPHEP)(bpy)][PF6]∙CH2Cl2, [Cu(BIPHEP)(5,5′-Me2bpy)][PF6]∙CH2Cl2, [Cu(BIPHEP)(6-Mebpy)][PF6]∙Et2O∙0.5H2O and [Cu(BIPHEP)(6-Etbpy)][PF6] confirm distorted tetrahedral {Cu(P^P)(N^N)} coordination environments. Each compound shows a quasi-reversible Cu+/Cu2+ process. In deaerated solution, the compounds are weak emitters. Powdered samples are yellow emitters (λemmax in the range 558–583 nm) and [Cu(BIPHEP)(5,5′-Me2bpy)][PF6] exhibits the highest photoluminescence quantum yield (PLQY = 14%). On cooling to 77 K (frozen 2-methyloxolane), the emission maxima are red-shifted and the excited state lifetimes increase from τ1/2 < 8 μs, to τ1/2 values of up to 53 μs, consistent with the compounds with N^N = 6-Mebpy, 6-Etbpy and 5,5′-Me2bpy exhibiting thermally activated delayed fluorescence (TADF).

Photolysis of Di-t-butylnitroxide

1982 ◽  
Vol 35 (3) ◽  
pp. 509 ◽  
Author(s):  
JM Coxon ◽  
E Patsalides
Keyword(s):  
Excited State ◽  
Light Intensity ◽  
Crystalline Solid ◽  
First Order ◽  
Deaerated Solution

Di-t-butylnitroxide (1) on photolysis in methylcyclohexane gives in addition to t-butoxy(di-t-buty1)-amine (7) and photolabile 2-methyl-2-nitrosopropane (2) a low yield of a white crystalline solid identified as a mixture of di-t-butylhydroxylammonium nitrate (13) and nitrite (14). Photolysis proceeds from the excited state produced by a π-π* transition, and in aerated solution is first order both with respect to nitroxide and light intensity. More complex kinetics are observed in deaerated solution.

γ-Radiolysis of some 1,4-quinones in benzene

1972 ◽  
Vol 25 (9) ◽  
pp. 1877
Author(s):  
JG Wilson ◽  
JW Sweeting
Keyword(s):  
Benzene Solution ◽  
Radiolysis Products ◽  
Deaerated Solution

The γ-radiolysis of several 1,4-quinones in benzene solution has been studied.� 1,4-Benzoquinone, 1,4-naphthoquinone, and 2-phenylnaphthoquinone undergo nuclear phenylation in deaerated solution. In aerated solution 1,4-benzoquinone is exceptional in being converted into 4-hydroxydiphenyl ether (13). Possible mechanisms for the formation of the radiolysis products are discussed.

Stabilization of Ascorbic Acid and Its Measurement by Liquid Chromatography in Nonfat Dry Milk

1987 ◽  
Vol 70 (5) ◽  
pp. 806-809
Author(s):  
Sam A Margolis ◽  
Iona Black
Keyword(s):  
Ascorbic Acid ◽  
Liquid Chromatography ◽  
Acid Content ◽  
Ascorbic Acid Content ◽  
Single Step ◽  
Independent Study ◽  
Dry Milk ◽  
Deaerated Solution ◽  
Chromatographic Procedure ◽  
Nonfat Dry Milk

Abstract The determination of ascorbic acid by liquid chromatography (LC) was improved by performing the analysis in the presence of solvents that had been purged with argon to reduce the concentration of oxygen. This methodological modification eliminated the oxidation of ascorbic acid during the chromatographic procedure and reduced the minimum detection level to 1 μg. Solutions of ascorbic acid have been successfully stabilized for 67 days by addition of dithiothreitol to a deaerated solution of water-acetonitrile (25 + 75 v/v), sealed under argon in amber vials and stored at -20°C. In a second independent study, a procedure for the extraction of ascorbic acid from nonfat dry milk in a single step was developed. The ascorbic acid content of Nonfat Dry Milk (SRM 1549) was determined by LC, using the method of standard additions. The mean ascorbic acid content was 54 ± 5 μg/g of sample. Analysis of variance of the analytical results indicates that there is a significant continual increase in the content of the ascorbic acid in each bottle from first to last sample

A Passive Film Formed on Alloy 600 in High Temperature Aqueous Solution

2008 ◽  
Vol 135 ◽  
pp. 103-106
Author(s):  
Dong Jin Kim ◽  
Hyuk Chul Kwon ◽  
Seong Sik Hwang ◽  
Hong Pyo Kim
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Oxide Film ◽  
Dissolved Oxygen ◽  
Passive Film ◽  
Alloy 600 ◽  
Pressure Condition ◽  
High Temperature And Pressure ◽  
Deaerated Solution ◽  
Temperature And Pressure

Alloy 600(74wt% Ni, 15wt% Cr, 9wt% Fe) is used as a material for steam generator tubing in pressurized water reactors(PWR) due to its high corrosion resistance under a PWR environment whose primary side and secondary side are operated under 340oC, 150bar and 290oC, 50bar, respectively. However, in spite of its outstanding corrosion resistance, a stress corrosion cracking(SCC) which has been one of the most important degradation issues, has occurred occasionally owing to the severe high temperature and pressure condition of a PWR. It is expected that a SCC is deeply related to an electrochemical property of a passive film formed under a high temperature and pressure condition. Therefore an understanding of the basic electrochemical behaviors regarding an anodic dissolution and a passivation of the bare surface of metals and alloys provides important information about a SCC mechanism and control. In the present work, the passive oxide films on Alloy 600 were investigated as a function of the dissolved oxygen content and the pH by using a potentiodynamic polarization, electrochemical impedance spectroscopy(EIS) and a depth profiling by Auger electron spectroscopy(AES). For this purpose, 0.5M H3BO3, 0.5M Na2SO4 and 0.1M NaOH aqueous solutions with/without dissolved oxygen at 300oC were used as the test solutions. The resistance of an oxide formed in an aerated solution was smaller than that in a deaerated solution while the oxide film in the aerated solution was thicker than the oxide film in the deaerated solution.

γ-Radiolysis of Cysteine-Cysteamine Disulfide in Aqueous Solution

1971 ◽  
Vol 49 (5) ◽  
pp. 725-730 ◽  
Author(s):  
J. W. Purdie
Keyword(s):  
Aqueous Solution ◽  
Disulfide Bonds ◽  
Low Oxygen ◽  
Chain Reactions ◽  
Mixed Disulfide ◽  
Deaerated Solution ◽  
A Chain ◽  
Protein Disulfide Bonds ◽  
High Yields ◽  
Protein Disulfide

γ-Radiolysis of a mixed disulfide, cysteine-cysteamine disulfide, in unbuffered aqueous solution (0.3 mM) was investigated in the presence and absence of oxygen. The principal products were the thiols (cysteine and cysteamine), the corresponding sulfinic and sulfonic acids, the symmetrical disulfides (cystine and cystamine) and ammonia. Cystine and cystamine were formed in very high yields in deaerated solution; (G(CySSCy) ~ 15) but addition of oxygen reduced the yield sharply and it was inversely proportional to the oxygen concentration except at very low oxygen levels. In aerated solution G(CySSCy) = 0.8. These observations were attributed to a chain reaction which was suppressed by oxygen:[Formula: see text]In the case of proteins, it was concluded that although chain reactions between RS• radicals and protein disulfide bonds were possible, they should be inhibited by oxygen.

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