Due to inereasing demands for mieroandlor high-precision parts, ultra-miert) cutting technologies hftve been developed at high speed, The importance of atmosphcre in micre cutting has beert reoognized morc and mora in Tecerit researches. This is because the effects of cuthng enyironments andlor surface oxidation ofa workpieee inerease when the scale of cuttirtg decreases, In this paper, based on the results of a series of cuttirig experimerrts, we discuss bow the atmospheric molecu!es affect the pertbrmance of microctnting. The cutting force, critical dqpth of eut and scratchcs fomied on the workpiece surface have been examined and compared between the resuks of cutting in air and those in yacuum environments.Tlie workpieces are silicon mono-erystals that have bcen exposed to air for various lerigths oftime after being cleaned with RCA method, The experimental results skow that brittlelductile trar:sition takes place with smaller depth of cut in air than in a vacuum. This impljes that thc briuleness of a silicon meno-erystal deereases in a vacuum.On the other han¢ from the comparison of results obtairred using a tool moving back and fbrth in air and in a vacuuml t't has also been found that cutting force decreases if atmospheric rnolecules are sandwiched betwecn a tool and chip durmg cutting. This could be because of thc lubrication effbct of the atmospheric molecules.
SynopsisTo clarify the behavior of fuel sulphur in blast furnaces. fuel oils with different sulphur cOlltents and benzelle or benzyl mercaptan with radioisotope 35 5 were illjected into three blast furnaces with inner volumes of 1 249Ill", 1 407 m 3 , and 1409 m 3 • Samples for chemical analysis were taken jimn IJig iron, slag. dust, and gases during experimental operation. The radioactive sullJhur in the samples was precipitated as barium sulphate and the radioactivity was determined by a low background counter.Experimental results are as follows:(1) Specific radioactivity of IJig iron and slag became constant in lIine to tell hours after the start qf filel oil iluection with the radioactive sullJlwr.(2) Th e behavior of jile! oil sullJllllr in thefumaces war lillie affected by the sulphur cOlltellt in theIllel oils, the quantity oI Iuel oil hUectioll. alld other olJeratillg conditinns.(3) The desullJllllrization rale offilel oil is slight(y bigger lhall the mean desullJlllIrizatioll rate q( all other blast furnace burdfll. The ralio of Ihe distribution ratio (5)/[5] Ior filel oil to that for other blast furnace burden was a/J/Jroxilllately 1.2.(4) If the ratio oI/lwl oil sul/Jh ur to the tolal .fIlllJh ur in the burdell increased, Ihe qualltily of sullJlm r ill /Jig iroll originated in the file! oil /Jroportionally increased.Thus, in ordn to keelJ the SIlI/Jllllr cOlllent of IJig iroll wilhin a certain vallie, it is necessary to use filel oil oI lower sulphur colltellt or tq rP"'ricl Ihe quantity of filel oil ilUected.
Oxygen precipitation in silicon heavily-doped with antimony, particularly at the concentration range higher than 7×1017 atoms/cm3, is known to be severely suppressed because of the doping concentration effect. This results in a reduction in internal gettering (IG) efficiency in the N/N+ epitaxial wafers. In this work, substrate wafers heavily-doped with antimony were pre-annealed prior to the epitaxial deposition process. Post-epitaxial annealing was used for enhancing precipitation in asdeposited epitaxial wafers. The results indicate that both pre- and post-epitaxial annealing can improve oxygen precipitation and IG efficiency. The relationship between oxide breakdown, generation lifetime and bulk defect density is observed.
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