Research on H2S Removal from Yellow Phosphorus Off-Gas through Catalytic-Oxidizing under Low Temperature and Oxygen Content

Research was conducted to illustrate relevant questions about H2S removal from yellow phosphorus off-gas through catalytic-oxidizing method. Following results have been found out. Firstly, Molecule sieve ZMS-5A, activated carbon ZP-1, ZP-2, ZP-3 and ZP-4 were used as carrier to identify their performances on H2S removal, among which ZP-4 was the optimum one. Secondly, among 3 different impregnants tested in experiments, Na2CO3 was the ideal one to be used as active ingredients of catalyst. And 7% was the suitable concentration of Na2CO3 according to experiments. Finally, catalyst made of carrier ZP-4 impregnated with 7% Na2CO3 was assessed comprehensively to investigate its performance on impurity removal of PH3, H2S, SO2, COS, and CS2. After purification total impurity content in yellow phosphorus off-gas was less than 10g/Nm3, which means purified gas can be used as material as mono-carbon chemical industry.

Conductivity Anisotropy in Epitaxial 6H and 4H Sic

ABSTRACTA measure of the electron mobility anisotropy in n-type 4H and 6H-SiC has been obtained using the Hall effect over the temperature range 80K<T<600K. Hall mobility and resistivity data are collected from appropriately oriented bar patterns fabricated into high quality epitaxial material grown on (1100) or (1120)surfaces having total impurity concentrations 1017-1018 cm-3. The observed mobility ratio for 4H is μ[1120]/[0001] and is independent of temperature. For 6H, the ratio μ[1100]/[0001] decreases from ∼6.2 at 80K to ∼5.0 at 150K and is essentially constant (∼4.8) above 200K. A donor level near 0.6 eV is occasionally observed in 4H which reduces the high temperature electron mobility and introduces an apparent temperature dependence to the mobility ratio if nonuniformly distributed.

Clusters in A Silane Glow Discharge: Mechanism of Their Formation and How to Avoid Them

The formation of clusters in glow discharge plasma processing is of great concern with respect to the production yield. Their appearance, trapping and transport in silane plasmas have been the subject of several publications, but little is known about the mechanism of their formation and growth and how to avoid them in intense discharges used for high rate deposition of amorphous silicon. We present mass spectrometric and light scattering data and theoretical modelling which show that the formation of clusters in a clean silane discharge (total impurity ≈ 10 ppm) is due to a sequential growth of higher silanes SinH2n+2 with a strong, catastrophic-like onset starting from pentasilane. A selfconsistent mechanistic model will be presented together with a discussion of alternative ionic mechanisms. Several possibilities of how to avoid the cluster formation at high deposition rates of a-Si will be discussed and documented.

Determination of Diclofenac Sodium and Related Compounds in Raw Materials and Formulations

A liquid chromatographic method has been developed for determination of drug and related compounds In diclofenac sodium raw material, slow-release, and enteric coated tablets. The method specifies a 5μm octadecylsllane bonded phase column, a mobile phase of tetrahydrofuran-acetonltrlle- buffer, pH 5 (1 + 4 + 8.3), and detection at 229 nm. The method resolves 10 known related compounds with limits of quantitation of 0.2% or less. Seventeen drug raw material samples were evaluated. Total Impurity levels ranged from 0.1 to 0.9%. The method has also been used for determination of drug content In raw materials and formulations. Mean assay levels In drug raw materials ranged between 98.3% and 101.8%.

Impurities and their Distribution in Temperate Glacier Ice

Total impurity content of salt plus carbon dioxide was estimated as a function of grain size and depth in polycrystalline ice samples cored from a temperate glacier by measuring the electrical conductivity of the melt with air excluded. Conductivity decreased with increasing depth and grain size and ranged from × 10-5 to 0.4 × 10-5 Ω -1 m-1 at 0°C. The conductivity of pure water at 0°C is 0.1 × 10-5 Ω -1 m-1 Studies of the configuration of the three phases and of in situ temperature were also made. Thermodynamic constraints indicate that these impurities are probably concentrated as follows: about 5 mol m-3 in the liquid in the veins along three-grain intersections, roughly 1 × 10-6 mol m-2 associated with grain-boundary area exclusive of veins, and about 0.7 × 10-3 mol m-3 in volume exclusive of veins and grain boundaries. The last of these categories seems to account for most of the impurities in coarse ice (grain size about 20 mm), but all three categories seem significant in fine ice (grain size about 2 mm). Differences in bulk impurity content possibly indicate different histories of flushing by water.

Impurities and their Distribution in Temperate Glacier Ice

Total impurity content of salt plus carbon dioxide was estimated as a function of grain size and depth in polycrystalline ice samples cored from a temperate glacier by measuring the electrical conductivity of the melt with air excluded. Conductivity decreased with increasing depth and grain size and ranged from × 10-5to 0.4 × 10-5Ω-1m-1at 0°C. The conductivity of pure water at 0°C is 0.1 × 10-5Ω-1m-1Studies of the configuration of the three phases and ofin situtemperature were also made. Thermodynamic constraints indicate that these impurities are probably concentrated as follows: about 5 mol m-3in the liquid in the veins along three-grain intersections, roughly 1 × 10-6mol m-2associated with grain-boundary area exclusive of veins, and about 0.7 × 10-3mol m-3in volume exclusive of veins and grain boundaries. The last of these categories seems to account for most of the impurities in coarse ice (grain size about 20 mm), but all three categories seem significant in fine ice (grain size about 2 mm). Differences in bulk impurity content possibly indicate different histories of flushing by water.

Isotherme galvanomagnetische Transport- koeffizienten bei Streuung quasifreier Ladungsträger an Dipolen / Isothermic galvanomagnetic transport coefficients of quasi-free carriers scattered, at dipole centres

It has been observed that in several semiconductors an in-crease in total impurity concentration leads to an increase in the low-temperature mobility due to pairing effects. The trans port coefficients rʜ, rQ' and rQ necessary for the analysis of the Hall effect and the magnetoresistance, in the event of di-pole scattering, are derived for the cases k a ≫ 3 and k a ≪ 3 (k = wave number of the quasi-free charge carrier, a = dipole length). For k a ≫ 3 the coefficients are dependent on tempe-rature, effective mass, and dipole length, whereas for k a ≪ 3 they are constant