نتایج جستجو برای: hematite

تعداد نتایج: 2566  

Journal: :Physical chemistry chemical physics : PCCP 2014
Halina K Dunn Johann M Feckl Alexander Müller Dina Fattakhova-Rohlfing Samuel G Morehead Julian Roos Laurence M Peter Christina Scheu Thomas Bein

Numerous studies have shown that the performance of hematite photoanodes for light-driven water splitting is improved substantially by doping with various metals, including tin. Although the enhanced performance has commonly been attributed to bulk effects such as increased conductivity, recent studies have noted an impact of doping on the efficiency of the interfacial transfer of holes involve...

1999
Richard J. Murphy John J. Lenhart Bruce D. Honeyman

In most aquatic systems, natural organic acids constitute an important pool of trace-metal binding ligands. The effect of natural organic matter (NOM) on metal ion sorption to mineral surfaces is a complex function of the environment in which the mineral and ions reside, as well as the source, molecular weight distribution and composition of the NOM. In spite of the well-acknowledged importance...

2017
Andrea Ranzani da Costa D. Wagner Fabrice Patisson A. Ranzani da Costa

In an effort to develop breakthrough technologies that enable drastic reduction in CO2 emissions from steel industry (ULCOS project), the reduction of iron ore by pure hydrogen in a direct reduction shaft furnace was investigated. After experimental and modelling studies, a 2D, axisymmetrical steady-state model called REDUCTOR was developed to simulate a counter-current moving bed reactor in wh...

Journal: :Environmental science & technology 2008
Yun Wang Dianne K Newman

Phenazines are small redox-active molecules produced by a variety of bacteria. Beyond merely serving as antibiotics, recent studies suggest that phenazines play important physiological roles, including one in iron acquisition. Here we characterize the ability of four electrochemically reduced natural phenazines--pyocyanin (PYO), phenazine-1-carboxylate (PCA), phenazine-1-carboxamide, and 1-hydr...

Journal: :international journal of environmental research 2014
a.l. ananthapadmanabha r. shankar k. sandeep

in this study we report the rock magnetic properties of surface soil samples and their spatialvariability from the northernmost district of kerala to understand pedogenic processes and soil erosion. themagnetic signal is mainly from fine grained pedogenic magnetite as other sources like anthropogenic andlithogenic magnetite, bacterial magnetite and greigite are absent. the surface soil samples ...

2009
Roger G. Burns

Introduction: An enigma of Venusian mineralogy is the suggestion that Fe3+bearing minerals exist under the reducing conditions of the Venusian atmosphere. Analysis of the spectrophotometric data from the Venera 13 and 14 missions, combined with the laboratory reflectance spectral measurements of oxidized basalts at elevatedtemperatures, led to the suggestion that metastable hematite might exist...

Journal: :Nano letters 2014
Sarath Ramadurgam Tzu-Ging Lin Chen Yang

The poor internal quantum efficiency (IQE) arising from high recombination and insufficient absorption is one of the critical challenges toward achieving high efficiency water splitting in hematite (α-Fe2O3) photoelectrodes. By combining the nanowire (NW) geometry with the localized surface plasmon resonance (LSPR) in semiconductor-metal-metal oxide core-multishell (CMS) NWs, we theoretically d...

1999
William L. Balsam John E. Damuth

Diffuse reflectance spectra measured during shipboard core description with a hand-held Minolta spectrophotometer are reliable data for interpreting sediment composition. Factor analysis of these spectra indicates that only Glad Cling Wrap, a polyethylene food wrap, should be used to cover wet cores during measurement because it introduces substantially less noise into the spectra than other b...

2016
Daria Jóźwiak-Niedźwiedzka Michał A. Glinicki Karolina Gibas

In the present study, the potential for the alkali–silica reaction (ASR) in radiation shielding concrete containing special aggregates is presented. The tests were performed on two kinds of aggregate: (1) high-density aggregate to absorb the gamma radiation (barite, magnetite, and hematite) and (2) mineral with high bound water content to attenuate the neutron flux (serpentinite). The optical m...

1999
HUIMING BAO PAUL L. KOCH

The magnitude and temperature-sensitivity of oxygen isotope fractionation in ferric oxide-water systems remain uncertain. In this study, three different synthetic methods are used to investigate the temperature dependence of the fractionation between water and hematite, akaganeite, and goethite at near-surface temperatures. Our results reveal two similarities among these ferric oxide-water syst...

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