Vapor-Phase Oxidation of Benzyl Alcohol Using Manganese Oxide Octahedral Molecular Sieves (OMS-2)

Vapor-phase selective oxidation of benzyl alcohol has been accomplished using cryptomelane-type manganese oxide octahedral molecular sieve (OMS-2) catalysts. A conversion of 92% and a selectivity to benzaldehyde of 99% were achieved using OMS-2. The role played by the oxidant in this system was probed by studying the reaction in the absence of oxidant. The natures of framework transformations occurring during the oxidation reaction were fully studied using temperature-programmed techniques, as well as in situ X-ray diffraction under different atmospheres

Relationship between the prevalence of antibodies to arbovirus and hepatitis B virus in the Vale do Ribeira region, Brazil

280 students, between 6 and 14 years old, residents in the Iguape county, southern coast of the State of São Paulo, were studied in order to identify the existence of a possible association between the prevalence of specific antibodies to the hepatitis B virus and the exposure to haematophagous mosquitoes, evaluated indirectly through the prevalence of antibodies to 17 arboviruses isolated in Brazil. The children were from 4 areas with different topographical characteristics: 89 of the children were from the urban zone of the town of Iguape, 89 were from the periurban zone, 30 were from the rural area with extensive banana plantations, and 72 were from the jungle zone. Previous studies had shown significantly higher prevalence of antibodies to different arboviruses in the cultivated zone and the jungle zone, when compared to the urban and periurban zones of Iguape. The detection of antibodies to the HBV surface antigen (HBs Ag) was done through the radioimmunoassay (Ausab, Abbott Laboratory). The cases considered positive were confirmed through the presence of anti-core HBV antibodies (anti-HBc-EIA Roche). A significantly higher prevalence of anti-HBV antibodies was observed in children from the jungle zone (26/72 = 36,1% ) when compared to those from the urban zone (5/89 = 5,6%), peri-urban (6/89 = 6,7%) or from the cultivated zone (0/30 = 0%). The result suggest the existence of a common factor in the dissemination of the arboviruses and the hepatitis B virus, supporting the hypothesis that mosquitoes may play an important role in the HBV transmission in tropical forested region

Sang et milieu intérieur du Nord-Vietnamien

Baylet R. J. Sang et milieu intérieur du Nord-Vietnamien. In: Bulletins et Mémoires de la Société d'anthropologie de Paris, X° Série. Tome 9 fascicule 4-6, 1958. pp. 130-137

Valeurs du volume sanguin chez le Nord-Vietnamien normal

Baylet R. J., Gamoty . Valeurs du volume sanguin chez le Nord-Vietnamien normal. In: Bulletins et Mémoires de la Société d'anthropologie de Paris, X° Série. Tome 9 fascicule 4-6, 1958. pp. 125-129

Effect of Ar and N-2 addition on CH4-H-2 based chemistry inductively coupled plasma etching of HgCdTe

International audienceMercury cadmium telluride (MCT) CH4-H-2 based chemistry inductively coupled plasma (ICP) etching mechanisms are investigated. The effect of Ar and N-2 addition in the mixture on plasma and MCT surface characteristics are studied by Langmuir probe, mass spectrometry, and x-ray photoelectron spectroscopy (XPS). In the authors' conditions, the HgTe faster removal than CdTe leads to the formation of a CdTe rich layer in the first 30 s of plasma exposure. Ion flux intensity and composition are only slightly influenced by N-2 addition while a strong effect is shown on neutral species by the formation of NH3, HCN, and the increase in CH3 radical density. At the opposite, Ar addition to the gas mixture leads to a total ion flux increase and promote CH3+ formation while small changes are observed on neutral species. In our low pressure and high density conditions, same order of magnitude of ion and neutral CH3 flux on MCT surface is found, suggesting a chemical contribution of CH3+ ions in MCT etching. This is confirmed by a strong correlation of the MCT etching yield versus total (neutral and ionic) CH3 flux. These results suggest that the etching is limited by the supply of CH3 to the surface

Groupes sanguins dans la population nord-vietnamienne du delta tonkinois

Baylet R. J., Ngog Hoan Vu. Groupes sanguins dans la population nord-vietnamienne du delta tonkinois. In: Bulletins et Mémoires de la Société d'anthropologie de Paris, X° Série. Tome 7 fascicule 5-6, 1956. pp. 400-403

Characterization of Plasma Etching Process Damage in HgCdTe

International audienceMicrostructural and electrical damage to n-type long-wavelength infrared Hg1−x Cd x Te (MCT) following CH4-H2-based inductively coupled plasma etching has been investigated. While the damage from such etching processes to MCT has previously been characterized for planar full-wafer etching, in this communication we present the results of an investigation of the damage incurred to etched sidewalls, whose faces constitute the majority of the etched surface in novel architectures. Auger electron spectroscopy was used to monitor the evolution of X Cd beneath etched surfaces. So far, no X Cd evolution has been detected underneath etched surfaces within a ΔX Cd = 0.02 resolution. Conductivity and minority-carrier lifetime have been studied on patterned photoconductors, from which it is possible to extract a surface recombination velocity (SRV). These studies have shown surface conductivity variations and SRV shifts of several orders of magnitude, depending on the etching process used