Oxide Analyses

Perhaps the first investigation into the chemical composition of the anodic oxide of HgCdTe was reported by Nemirovsky and Finkman in 1979 (50). Anodic oxide films were grown on n-type slush grown (Hg,Cd)Te (Ej = 0.1 eV) in 0.1 N KOH in methanol and various concentrations ( 0.1 N) of KOH in 90% ethylene glycol /10% HjO. The material surface was mechanically polished and etched in 20% Br in methanol prior to anodization. The refractive index and dielectric constant of the oxide were determined to be closer to TeOj than CdO or HgO, so the authors concluded that the 

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In addition to pyro-refining, cmde oxide analysing 80—95% can be refined by a wet process (6). In this process advantage is taken of the fact that the solubihty of arsenic trioxide in water increases with temperature as follows ... 

The potential compound composition of a cement or cement clinker can be calculated from the oxide analyses of any given raw materials mixture, or from the oxide analyses of the cement clinker or finished cement. The simplest and most widely used method is the Bogue calculation (23). The ASTM C150 (24) calculation is somewhat modified. 

After chlorination, beakers were removed from the sunlight at regular (usually 30-min) intervals, placed in a dark box, and the contents analysed for bromate and residual oxidants without delay. Residual oxidants analyses were performed by the Ij spectrophotometric titration procedure described by Carpenter [19] with a pH of 2 and potassium iodide concentration of 4 g/1. Bromate... 

Chemiluminescent techniques have been used to determine nanomolar quantities of nitrate and nitrite in seawater [124,125]. This method depends on the selective reduction of these species to nitric oxide, which is then determined by its chemiluminescent reaction with ozone, using a commercial nitrogen oxides analyser. The necessary equipment is compact and sufficiently sturdy to allow shipboard use. A precision of 2nmol/l is claimed, and an analytical range of 2nmol/l with analysis rates of 10-12 samples hourly. 

In this metho d [ 124 ] nitrate, nitrate plus nitrite or nitrite alone are selectively reduced to nitric oxide, which is swept from the sample in a helium carrier gas flow. Nitric oxide is allowed to react with ozone in a nitrogen oxide analyser, where it forms nitrogen dioxide. The return of the nitrogen dioxide to the ground state is accompanied by release of a photon, which is detected by a photomultiplier. The integrated output of the photomultiplier over the time that the nitric oxide is pinged from the sample is proportional to the nitrite content of the sample. 

Such studies, and others on an O-phosphonomannan155 and a tei-choic acid,168 relied on judicious comparisons (of shift) with signals of model compounds, and these are simpler than conventional, analytical procedures. For example, it is difficult to methylate alkali-labile O-phosphonomannans, and sialic acid and KDO-containing polymers would require difficultly available, O-methylated standards. In addition, periodate-oxidation analyses are restricted to polymers having fortuitously amenable, chemical structures. 

At the time these experiments were made an erroneous value for the atomic weight of silver was in use, in consequence of which the value Fe—55-87, in confirmation of that deduced from the oxide analyses, was deduced from the bromide analyses. With the establishment of the modern value for the atomic weight of silver, it accordingly... 

The two other demands can be satisfied by laborious and analogous comparisons between oxide analyses and the coal properties found by experience or experiments which affect performance. 

Regression analyses of ash oxide analyses converted with this relationship did not result in a useful correlation when the weight percentages of ash components were applied exclusively. Realistic dependencies could be found when an iron oxide parameter T Fe was introduced in combination with the influence of the fuel sulfur the sulfur influence decreased at high sulfur concentrations. There is a statistical relationship for a slagging tendency called fg which refers to a predicate interval of... 

Interpretation methods based on ash oxide analyses should always be understood as makeshift solutions to which experimental methods are preferred when they are similar to practical conditions. One example of the latter methods should be emphasized. It is a micromethod resulting from the cooperation between Dresden and Budapest (Schneider (18 ), Boross, Horvath, Voros (19)). A reaction pipe similar to that of Field (Figure 5) is used to observe the formation of deposits quantitatively on cooled or non-cooled heating surfaces which are subjected to the mineral substance of coal particles burnt completely or partially in the equipment at defined conditions (temperature, grain size and gas composition). The selected reaction time for these particles permits the degree of burn-out to be varied. This combustion reactor provides a method to avoid the great effort required by large scale test combustion chambers. 

The functional principle behind nitrogen oxides analysers is generally the reaction of nitric oxide with ozone to yield excited nitrogen dioxide and water. The transition of the excited molecule to the ground state is accompanied by the release of radiant energy, which is suitably measured ... 

Fig. 15.23 Block diagram of nitrogen oxides analyser. (Courtesy of Columbia Scientific Industries Corporation). 

Four partially acetylated D-gluco-D-mannans have been isolated from the leaves of Aloe vera The polysaccharides differed in the ratio of D-glucose to D-mannose as well as in their acetyl content. The results of methylation and periodate-ion oxidation analyses sTiowed that the polymers were all linear with only (1 -> 4) linkages present. 

The structure of the laminaran from Eisenia bicyclis has been determined by methylation and periodate ion oxidation analyses as well as by and n.m.r. spectroscopies. The polysaccharide possessed a branched structure with both (1- 3)- and (16)- 3-D-glucopyranose residues being present in the ratio of 3 2. 

Three neutral D-glucoglycerolipids have been isolated from the alveolar lavage of rabbits and their structures (27)-(29) were determined by mild alkaline hydrolysis, methylation, periodate and chromium(vi) oxide oxidation analyses. A further sulphated D-glucoglycerolipid (30) was also isolated and characterized by the same procedures applied to the mature and desulphated lipid. ... 

To find the quantity of metal dissolved in the exhaust lubricant as a result of their interaction with the products obtained from their oxidation, analyses of their composition... 

Percentage of total rare earth oxide. Analyses adjusted to 100% REO. 

A major glycophosphoceramide from tobacco leaves, named PSL-I, has been characterized from the results of methylation, and periodate and chromium(vi) oxide oxidation analyses to have the structure (20)." Six other novel... 

In the operation of the dynamic sodium corrosion loop it was found that several hours of operation were required to stabilize the oxide concentration, The loop has inherent cold trapping characteristics, and an equilibrium concentration is not achieved until the loop has been in operation long enough for a re-distribution of oxide to occur. The oxide analyses have been made by the distillation method, which has proved to be very satisfactory for high-temperature sampling. 

TPO (Temperature Programmed Oxidation) analyses have been carried out after catalytic tests in order to detect the amount of residual caibon from the amount of caibon-containing products (CO+CO2). The hearing program of TPO permits to reach 1000°C with a rate of 15°C/min under a mixture of oxygen (10vol%) in helium. 

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