scholarly journals Carbon Implanted in Optical Grade Fused Silica: Annealing Effects in Reducing and Oxidizing Atmospheres

1996 ◽  
Vol 438 ◽  
Author(s):  
Y. S. Tung ◽  
R. Mu ◽  
A. Ueda ◽  
D. O. Henderson ◽  
P. W. Wang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Infrared Spectroscopy ◽  
Fused Silica ◽  
Infrared Measurements ◽  
Annealing Effects

AbstractCarbon is implanted into fused silica with doses of 1, 3, 6, 10×1016 ions/cm2. Infrared spectroscopy has identified the formation of CO and CO2 molecules in the implanted glasses. The relationships among concentrations of carbon dioxide, carbon monoxide and carbon doses are established by the infrared measurements. Annealing under different atmospheres have dramatic effects on CO and CO2 concentrations.

Methyleneketenes and methylenecarbenes. VII. Evidence for the pyrolytic generation of methyleneketene (propadienone)

1977 ◽  
Vol 30 (1) ◽  
pp. 179 ◽  
Author(s):  
RFC Brown ◽  
FW Eastwood ◽  
GL McMullen
Keyword(s):  
Mass Spectrometry ◽  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Methylene Chloride ◽  
Liquid Nitrogen Temperature ◽  
Pyrolysis Products ◽  
Flash Vacuum Pyrolysis ◽  
Vacuum Pyrolysis ◽  
Infrared Measurements ◽  
Methanol Vapour

Oxidation of 2,2,5-trimethyl-5-phenylseleno-1,3-dioxan-4,6-dione with m-chloroperbenzoic acid in methylene chloride gives a solution containing 2,2-dimethylspiro[1,3-dioxan-5,2'-oxiran]-4,6-dione and the unstable 2,2-dimethyl-5-methylene-1,3-dioxan-4,6-dione, which forms stable adducts with cyclohexadiene and cyclopentadiene. Flash vacuum pyrolysis of the cyclopentadiene adduct over the temperature range 460- 570° and detection of the components present in the pyrolysate by mass spectrometry showed that cyclopentadiene, acetone, carbon dioxide and methyleneketene (CH2=C=C=O) are formed; the last breaks down into acetylene and carbon monoxide at higher temperatures (520-570°). Infrared measurements on the pyrolysis products kept at liquid nitrogen temperature showed absorption near 2100 cm-1 which is attributed to methyleneketene. Reaction of the pyrolysate with aniline vapour or methanol vapour yielded acrylanilide and methyl acrylate respectively. Pyrolysis in the absence of trapping agents gave a glassy solid on an uncooled glass surface. This solid is considered to be formed by addition of methyleneketene to 2,2-dimethyl-5-methylene-1,3-dioxan-4,6- dione. Methanolysis of the solid and esterification with diazomethane gave dimethyl 2-methoxycarbonyl-4-methylenepentanedioate.

scholarly journals Controlled atmosphere GMAW welding of transportation vehicles and production machines parts made from 30MnB5 steel

2018 ◽  
Vol 216 ◽  
pp. 03001 ◽  
Author(s):  
Evgeny Ivanayskiy ◽  
Aleksei Ishkov ◽  
Aleksandr Ivanayskiy ◽  
Iakov Ochakovskii
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Chemical Composition ◽  
Controlled Atmosphere ◽  
Shielding Gas ◽  
Reducing Atmosphere ◽  
Metal Composition ◽  
Gmaw Welding ◽  
Welding Materials

The paper studies the influence of shielding gas on the composition and the structure of weld joint metal of 30MnB5 steel applied in essential parts of automobiles and tractors. The welding was performed in inert, oxidizing and reducing atmospheres. It was established that TIG welding with argon used as shielding gas did not provide the required mechanical properties when using conventional welding materials. Carbon dioxide during MAG welding caused partial burning of alloying elements. Carbon monoxide used as shielding gas was proved to form reducing atmosphere enabling to obtain chemical composition close to the base metal composition. Metallographic examinations were carried out. The obtained results provided full-strength weld, as well as the required reliability and durability of welded components and joints.

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