Hydrogen dilution

The ring opening reactions of N-alkylideneaziridines, e.g. (313), with hydrogen, dilute hydrochloric acid and phenol have also been reported and are outlined below (80AG(E)276). 

Bonding is used extensively on steel. The reaction occurs with a high hydrogen dilution of the BCI3 to prevent substrate attack. An iron boride is formed. 1 1 Not all metals, however, are suitable to bonding. For instance, the bonding of titanium by CVD in a chloride-based system is more difficult since the titanium substrate is highly susceptible to HCl attack and the rate of diffusion is low. 

Another deposition reaction uses disilane as the silicon source at atmospheric pressure and at a deposition temperature of290-300°C, with nitrogen and hydrogen dilution as follows ... 

As always in chemisorption measurements, pretreatment of the samples should be done with care. For metal catalysts prepared from oxides in particular this is experimentally troublesome because a reduction step is always needed in the preparation of the metal catalyst. Hydrogen or hydrogen diluted with an inert gas is usually used for the reduction but it is difficult to remove adsorbed H2 from the surface completely. So, after reduction the metal surfaces contains (unknown) amounts of H atoms, which are strongly retained by the surface and, as a consequence, it is not easy to find reliable values for the dispersion from H2 chemisorption data. 

The addition of a hydrogen flow to the silane flow often is used to improve the material quality of the deposited film. Moderate hydrogen dilution of silane... 

Hydrogen dilution also improves the quality of a-SiGe H alloys [369], An a-SiGeiH bottom cell must be designed to operate at long wavelengths, with rela-... 

Cyclododecene may be prepared from 1,5,9-cyclododecatriene by the catalytic reduction with Raney nickel and hydrogen diluted with nitrogen, with nickel sulfide on alumina, with cobalt, iron, or nickel in the presence of thiophene, with palladium on charcoal, with palladimn chloride in the presence of water, with palladium on barium sulfate, with cobalt acetate in the presence of cobalt carbonyl, and with cobalt carbonyl and tri- -butyl phosphine. It may also be obtained from the triene by reduction with lithium and ethylamine, by disproportionation, - by epoxidation followed by isomerization to a ketone and WoliT-Kishner reduction, and from cyclododecanone by the reaction of its hydrazone with sodium hydride. ... 

Tsu DV, Chao BS, Ovshinsky SR, Guha S, Yang J (1997). Effect of hydrogen dilution on the structure of amorphous silicon alloy. Appl Phys Lett 71 1317-1319... 

Koh J, Ferlauto AS, Rovira PI, Wronski CR, Collins RW (1999) Evolutionary phase diagram for plasma enhanced chemical vapor deposition of silicon thin films from hydrogen diluted silane. Appl Phys Lett 75 2286-2289... 

The reactor tube was brought to the required temperature under an atmosphere of argon. A mixture of nitric oxide and carbon monoxide or hydrogen, diluted by argon was then introduced into the reacting part of the quartz tube. The gaseous reaction products were intermittently withdrawn from the reactor and analyzed by a chemiluminescent NOx analyzer and a gaschromatograph. Ammonia was measured by detector tube method. The scope of the experiment is shown in Table II. 

On the other hand, the formation of structure defects (micro cracks, dislocations) in metals and alloys is accompanied by redistribution of concentration of hydrogen diluted in these species. 

Approximation of the experimental extraction curve by the calculated curve with a proper choice of the initial concentrations Cn, and constants uitD0i allows one to obtain the activation energy and diffusion constants for hydrogen diluted in the... 

In summary, under the circumstance of hydrogen dilution it is possible to observe hydrogen oxidation behaviours in the high-frequency range of the EIS. 

Although the hydrogenation of various acetylenic compounds is industrially very important and scientifically an interesting problem to study, the information gathered up to now is still insufficient to answer all questions. So, for example, the debate is still continuing on the problem whether the hydrogen diluted in metals plays a role or not, or whether the carbonaceous layer (instead of unoccupied metal sites) is the locus of hydrogenation of acetylene or not, etc. (see e.g. the discussion in ref. 80). 

It has been reported [24] that PEFC stacks with anodes of high platinum loading (typically 4 mg Pt/cm, in the form of a platinum black/PTFE mixture), when operating on a mixture of 75% Ha -f 25% COa, have suffered performance losses significantly greater than expected from hydrogen dilution eflfects alone. Figure 16... 

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