Todorokite with Long Spacing and Structure of Manganese Dioxide Minerals

Crystalline todorokite associated with biogenic debris in manganese nodules.

Platy intergrowths of crystalline todorokite are associated with biogenic debris in the cores of manganese nodules from a site in the Pacific Ocean. Analyses by electron diffraction and transmission electron microscopy demonstrate that this material is composed of tunnels of chains of linked MnO(6) octahedra. The chemical composition, morphology, and stability of the todorokite differ from thos...

Nanocrystalline todorokite-like manganese oxide produced by bacterial catalysis.

We describe the characterization of an unknown and difficult to identify but geochemically and environmentally significant MnOx structure produced by a freshwater bacterium, Leptothrix discophora SP-6, using combined transmission electron microscopy (TEM), extended X-ray absorption fine structure (EXAFS), and UV Raman spectroscopy. The large surface-to-volume ratio of the needle-shaped nanocrys...

the underlying structure of language proficiency and the proficiency level

هدف از انجام این تخقیق بررسی رابطه احتمالی بین سطح مهارت زبان خارجی (foreign language proficiency) و ساختار مهارت زبان خارجی بود. تعداد 314 زبان آموز مونث و مذکر که عمدتا دانشجویان رشته های زبان انگلیسی در سطوح کارشناسی و کارشناسی ارشد بودند در این تحقیق شرکت کردند. از لحاظ سطح مهارت زبان خارجی شرکت کنندگان بسیار با هم متفاوت بودند، (75 نفر سطح پیشرفته، 113 نفر سطح متوسط، 126 سطح مقدماتی). کلا ...

Todorokite-type manganese oxide nanowires as an intercalation cathode for Li-ion and Na-ion batteries

Manganese minerals in geodes from Chihuahua, Mexico

Seven manganese minerals have been observed in geodes from Chihuahua, Mexico. Ramsdellite occurs in a number of different habits, but the morphology and precession X-ray patterns suggest that it is pseudomorphous after groutite. Pyrolusite is found only in association with ramsdellite and is believed to be an alteration product of that mineral. Todorokite generally occurs as a late-stage fibrou...