Graphite oven

An atomisation source flame, graphite oven, etc. (we are here only concerned with the flame)... 

Graphite ovens heated by the Joule effect where the whole sample is introduced at once leading to a variable, peak-shaped, signal. 

The continuous spectnun emission lamp, used for flame or electrothermal graphite oven atomisation... 

AAS using a graphite oven also yields a good sensitivity (15 ng mL ), but loss of volatile Ge must be avoided. The combination of extraction-spectrophotometry and AAS after extraction of Ge tetrachloride with CCI4 brings about new advantages. A detection limit of 5 ng mL with a standard deviation of 6% was obtained (Schleich and Henze 1990). Shinohara et al. (1999) reported a detection limit of Ge standard so-... 

Atomic absorption spectrometry using a graphite oven also yields a good sensitivity (15 ng/mL loss of volatile germanium must be avoided). 

This technique of halogen atom production is not unique to fluorine in fact, the first halogen atom beam produced in this laboratory was a chlorine atom beam produced by dissociation of CI2, in argon buffer gas in a heated graphite oven (32). The technique should be applicable to all of the halogen atoms and a vast variety of scattering experiments can be initiated using such sources. 

Pitch Coke. The manufacture of pitch coke provides a large toimage oudet for coke-oven pitch in Japan, the CIS and, until more recently, Germany (75,76). Pitch coke is used either alone or mixed with petroleum coke as the carbon component of electrodes, carbon bmshes, and shaped carbon and graphite articles. 

The principal binder material, coal-tar pitch, is produced by the distillation of coal tar. Coal tar is obtained primarily as a by-product of the destmctive distillation of bituminous coal in coke ovens during the production of metallurgical coke. Petroleum pitch is used to a much lesser extent as a binder in carbon and graphite manufacture. Because of its low sohds content, petroleum pitch is used as an impregnant to strengthen carbon artifacts prior to graphitization. 

The anodes of these two graphite samples were fabricated from a slurried mixture which contains 92 wt% of active graphite powder and 8wt% polyvinylidene difluoride (PVDF) polymer binder (Kureha 9130) and using 1 -methyl-2-pyrrolidinone (NMP) (Aldrich, >99%) as the solvent. After getting the homogenous slurry, the electrode laminates were coated on Cu current collector foil using a doctor blade in the laboratory-made laminate-coater. The laminates were then dried first at 75°C in air for 3 hrs and then the final heat treatment was carried out in a vacuum oven at 75 C for 10 hrs. Finally, the laminates were calendared to about 35% porosity in a dry room. 

Platinum was introduced on the activated support by a competitive cation exchange technique. An amount of 100 g of a 8 wt% Pt solution of platinumtetrammine hydroxide (Johnson Matthey) was added dropwise to a suspension of 40 g graphite in 800 ml 1 M ammonia (Merck p.a.) and stirred at ambient temperature for 24 hours. The catalyst was subsequently separated by filtration on a Millipore filter (HV 0.45m), washed with distilled water and dried in a vacuum oven at 373 K. The dried catalyst was reduced in flowing hydrogen at 573 K for 2 hours and stored under air before use. 

The thermal device used to elevate the temperature consists of a burner fed with a gaseous combustible mixture or, alternatively, in atomic absorption, by a small electric oven that contains a graphite rod resistor heated by the Joule effect. In the former, an aqueous solution of the sample is nebulised into the flame where atomisation takes place. In the latter, the sample is deposited on the graphite rod. In both methods, the atomic gas generated is located in the optical path of the instrument. 

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