نتایج جستجو برای: magnetite

تعداد نتایج: 5235  

2009
Hynek Biederman Milan Tichý Danka Slavínská Pavel Kudrna Ondřej Kylián Jan Hanuš Andrey Shukurov Jaroslav Kousal Martin Drábik

Magnetite-ENR polymer electrolytes doped with various % wt of LiCF3SO3 salt were synthesized in-situ in the presence of ENR and cast into film doped with LiCF3SO3. XRD results confirmed the purity of the as-formed magnetite particles. The diffraction peaks assigned for LiCF3SO3 become more intense as the concentration of salt is increased. FTIR analyses showed that both “free” (dissociation) an...

2015
Christine Rümenapp Friedrich E. Wagner Bernhard Gleich

Magnetic nanoparticles made of magnetite have the advantage to be biocompatible and to have a good saturation magnetisation. In this work we show that magnetite nanoparticles change their magnetic and chemical characteristics over time, depending on their storage conditions. To determine the oxidation state of the iron in the core of the nanoparticles Mössbauer spectroscopy was used at 4.2 K. T...

Journal: :Journal of colloid and interface science 2006
E Illés E Tombácz

The pH-dependent adsorption of humic acid (HA) on magnetite and its effect on the surface charging and the aggregation of oxide particles were investigated. HA was extracted from brown coal. Synthetic magnetite was prepared by alkaline hydrolysis of iron(II) and iron(III) salts. The pH-dependent particle charge and aggregation, and coagulation kinetics at pH approximately 4 were measured by las...

Journal: :The Journal of experimental biology 1981
J L Kirschvink

In recent years, a variety of animals have been found which are able to synthesize the ferromagnetic mineral magnetite (Fe 3 O 4). Lowenstam (1962) originally recognized biogenic magnetite in the radular teeth of a primitive marine mollusc, the chiton (Polyplacophora), and since then it has been identified as a precipitate in several magnetically sensitive organisms, including honey bees also r...

2012
K. C.

The separation factor, aM-0= ( 1 8 0 / 1 6 0 ) magnetite/' ( 1 8 0 / 1 6 0 ) atmospheric oxygen, between the magnetite crust of iron meteorites and atmospheric oxygen has been determined to be 0.9946 ± 0.0005. It is concluded that this fractionation of the oxygen isotopes is the consequence of an equilibrium isotope effect at high temperatures. It can be assumed that this is also valid for cosm...

Journal: :Chemical communications 2009
Xiao Jia Dairong Chen Xiuling Jiao Shumei Zhai

Water-dispersible Fe(3)O(4) nanoparticles have been prepared by a simple solution method, in which the particle size (3-11 nm) can be tuned by simply adjusting the reaction temperature and time; the formation mechanism of Fe(3)O(4) nanoparticles is proposed and their low cytotoxicity has also been proved.

Journal: :Chemical research in toxicology 2011
Mathias Könczöl Sandra Ebeling Ella Goldenberg Fabian Treude Richard Gminski Reto Gieré Bernard Grobéty Barbara Rothen-Rutishauser Irmgard Merfort Volker Mersch-Sundermann

Airborne particulate matter (PM) of varying size and composition is known to cause health problems in humans. The iron oxide Fe(3)O(4) (magnetite) may be a major anthropogenic component in ambient PM and is derived mainly from industrial sources. In the present study, we have investigated the effects of four different size fractions of magnetite on signaling pathways, free radical generation, c...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2016
Reto Gieré

Magnetite is an iron-oxide mineral that occurs naturally on Earth. Because it is also an important component of many anthropogenic materials (e.g., coal fly ash) and synthetic products (e.g., black toner powders), magnetite can be released to the environment through human activities (1). In PNAS,Maher et al. (2) describe the abundant presence in the human brain of magnetite nanoparticles, some ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2004
Benjamin P Weiss Soon Sam Kim Joseph L Kirschvink Robert E Kopp Mohan Sankaran Atsuko Kobayashi Arash Komeili

Transmission electron microscopy studies have been used to argue that magnetite crystals in carbonate from Martian meteorite ALH84001 have a composition and morphology indistinguishable from that of magnetotactic bacteria. It has even been claimed from scanning electron microscopy imaging that some ALH84001 magnetite crystals are aligned in chains. Alignment of magnetosomes in chains is perhaps...

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