نتایج جستجو برای: high manganese

تعداد نتایج: 2078448  

2015
Matthew H. H. Fischel Jason S. Fischel Brandon J. Lafferty Donald L. Sparks

BACKGROUND Manganese-oxides are one of the most important minerals in soil due to their widespread distribution and high reactivity. Despite their invaluable role in cycling many redox sensitive elements, numerous unknowns remain about the reactivity of different manganese-oxide minerals under varying conditions in natural systems. By altering temperature, pH, and concentration of arsenite we w...

Journal: :Physical chemistry chemical physics : PCCP 2013
Dachao Hong Yusuke Yamada Akifumi Nomura Shunichi Fukuzumi

NiMnO3 was found to be an efficient catalyst for light-driven water oxidation using [Ru(bpy)3](2+) and S2O8(2-) as a photosensitiser and a sacrificial oxidant, respectively. NiMnO3 exhibited remarkably high catalytic activity in comparison with manganese oxides and nickel oxide. For electrochemical water oxidation, the highest catalytic current was also obtained with NiMnO3 among the manganese ...

2008
D. J. Norris Nan Yao T. A. Kennedy

We demonstrate high-quality, highly fluorescent, ZnSe colloidal nanocrystals (or quantum dots) that are doped with paramagnetic Mn2+ impurities. We present luminescence, magnetic circular dichroism (MCD), and electron paramagnetic resonance (EPR) measurements to confirm that the Mn impurities are embedded inside the nanocrystal. Optical measurements show that by exciting the nanocrystal, effici...

2008
D. J. Norris Nan Yao T. A. Kennedy

We demonstrate high-quality, highly fluorescent, ZnSe colloidal nanocrystals (or quantum dots) that are doped with paramagnetic Mn2+ impurities. We present luminescence, magnetic circular dichroism (MCD), and electron paramagnetic resonance (EPR) measurements to confirm that the Mn impurities are embedded inside the nanocrystal. Optical measurements show that by exciting the nanocrystal, effici...

Journal: :Journal of the Royal Society, Interface 2012
Mohammad Mahdi Najafpour Fahimeh Rahimi Eva-Mari Aro Choon-Hwan Lee Suleyman I Allakhverdiev

There has been a tremendous surge in research on the synthesis of various metal compounds aimed at simulating the water-oxidizing complex (WOC) of photosystem II (PSII). This is crucial because the water oxidation half reaction is overwhelmingly rate-limiting and needs high over-voltage (approx. 1 V), which results in low conversion efficiencies when working at current densities required for hy...

Journal: :Organic letters 2014
Duyi Shen Chengxia Miao Shoufeng Wang Chungu Xia Wei Sun

A benzimidazole-based nonheme manganese complex efficiently catalyzes benzylic, aliphatic C-H as well as tertiary C-H oxidation with hydrogen peroxide as the oxidant in the presence of acetic acid as additive. (18)O labeling experiments suggest the reaction may proceed via a high-valent manganese-oxo intermediate.

Journal: :Organic & biomolecular chemistry 2014
A Poeschl D M Mountford

A high yielding manganese dioxide mediated oxidation of benzylamines to the corresponding amides has been developed under mild reaction conditions. The mechanism for the conversion has been explored by (1)H NMR spectroscopy and the role of both manganese dioxide and molecular sieves in the reaction elucidated.

Journal: :Toxicological sciences : an official journal of the Society of Toxicology 2008
Christoffer Tamm Farideh Sabri Sandra Ceccatelli

Manganese is an essential nutrient for humans that has to be maintained at proper levels for normal brain functioning. However, manganese also acts as a toxicant to the brain, and several studies have linked exposure to excessive manganese to neurotoxicity in adults. A recent report has suggested that ingesting high doses of manganese via drinking water can impede intellectual functions in chil...

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