Oriented precipitate complexes in iron-rich olivines produced experimentally in aqueous oxidizing environment     

Kazuake Iishi  Kazunobu Torigoe  Xiaojun Han 《Physics and Chemistry of Minerals》1997,25(1):8-14

 Iron-rich olivines (Fa₁₀₀∼Fa₇₀Fo₃₀) experimentally altered in alkaline and acidic aqueous oxidizing environment were examined in transmission electron microscope to determine the precipitate phases and their crystallographic relationships to the host. The planar zones consist of precipitates of laihunite and hematite in alkaline aqueous oxidizing environment while hematite and amorphous silica in acidic aqueous oxidizing environment. The directions of planar zones produced in alkaline aqueous oxidizing environment are parallel to (100)∼(001) of olivine dependent on the composition of the host olivines, while those produced in acidic aqueous oxidizing environment are always parallel to (001) of olivine independent from the composition of the host olivine. These differences are interpreted by the dissolution kinetics of olivine. The present experimental results explain why the planar zones found in oxidized iron-rich olivines in carbonaceous chondrite are parallel to (100) of olivine while those in terrestrial olivines are parallel to (001) of olivine. That is, the difference is attributed to the pH of the alteration environment. Received: August 19, 1996 / Revised, accepted: February 14, 1997  相似文献   

Degradation of crude oils byPseudomonas sp. in enriched seawater medium     

Akihiko Murakami  Kazunobu Suzuki  Akiko Yamane  Tadao Kusama 《Journal of Oceanography》1985,41(5):337-344

Microbial degradation of five crude oils such as Arabian light, Berri, Murban, Khafji and Minas crude oil by a pure bacterial strain,Pseudomonas sp. isolated from the sea water sampled at Kawasaki Harbor in Tokyo Bay, was studied experimentally in the enriched seawater medium.The degradation of crude oils was determined in total residual oil and in four fractions of saturated, aromatics, asphaltene and column residue by use of the column chromatography with activated alumina.The saturated fraction was shown to be most biodegradable. The aromatics followed for all five crude oils examined and the asphaltene was biodegradable to some extent. The column residue was not apparently degraded byPseudomonas sp. within 30 days. Each of Arabian light, Berri or Murban crude oil was degraded from 59 to 63.5 %, Khafji crude oil 49 % and Minas crude oil, solid at room temperature, only 33 %. Degradation rate of the five crude oils was determined to be in a range from 2.88 to 17.3 mg-oil 1^–1 hr^–1 or from 6.0×10^–12 to 1.56×10^–10 mg-oil cell^–1 hr^–1. Relative degradation ofn-paraffins of different carbon numbers in the saturated fraction was found to be similar regardless of carbon number for the five crude oils.  相似文献