نتایج جستجو برای: hydrothermal

تعداد نتایج: 16947  

Journal: :Nanotechnology 2006
A Wei X W Sun C X Xu Z L Dong Y Yang S T Tan W Huang

Tubular ZnO microstructural arrays were fabricated by a hydrothermal decomposition method. The dependence of the morphologies on the growth time and temperature was investigated in detail. An experiment was carried out to determine the mechanism of tubular ZnO formation. Our results showed that ZnO microtubes originated from an ageing process from ZnO microrods at a lower temperature (compared ...

Journal: :Current opinion in chemical biology 2003
James F Holden Michael W W Adams

Marine hydrothermal microorganisms respond rapidly to changes in the concentrations and availability of metals within their environment. Hyperthermophilic archaea appear to possess novel mechanisms for metal detoxification, dissimilatory metal reduction and metal assimilation that may be absent in their mesophilic and bacterial counterparts. For example, tungsten was found in high concentration...

Journal: :international journal of nano dimension 0
s. manafi department of ceramics, shahrood branch, islamic azad university, shahrood, iran. m. r. rahimipour materials and energy research center, p.o. box 14155-4777, tehran-iran. i. mobasherpour materials and energy research center, p.o. box 14155-4777, tehran-iran. a. soltanmoradi department of ceramics, shahrood branch, islamic azad university, shahrood, iran.

in the present work, we report a suitable approach for the preparation of batio3 nanostructures via the hydrothermal condition using dolapix et85 as surfactant. the powders were investigated by x-ray diffraction (xrd), scanning election microscopy (sem), energy-dispersive x-ray spectroscopy (edax), field emission transmission electron microscopy (fetem), selected area electron diffraction (saed...

2017

Hydrothermal processes on Enceladus Saturn’s moon Enceladus has a subsurface ocean covered by a layer of ice. Some liquid escapes into space through cracks in the ice, which is the source of one of Saturn’s rings. In October 2015, the Cassini spacecraft flew directly through the plume of escaping material and sampled its chemical composition. Waite et al. found that the plume contains molecular...

Journal: :Science and technology of advanced materials 2009
Sunandan Baruah Joydeep Dutta

One-dimensional nanostructures exhibit interesting electronic and optical properties due to their low dimensionality leading to quantum confinement effects. ZnO has received lot of attention as a nanostructured material because of unique properties rendering it suitable for various applications. Amongst the different methods of synthesis of ZnO nanostructures, the hydrothermal method is attract...

2015
Dalia Ahmed Mohammed Osman Mustafa Abbas Mustafa

Low-temperature aqueous chemical growth methods have shown great potential in the synthesis of ZnO nanostructures. Hexamethylenetetramine (HMTA) is the most common chemical substance used in the hydrothermal synthesis. In this study zinc oxide nanoparticles were prepared via hydrothermal growth using zinc acetate dihydrate and sodium hydroxide, as precursors instead of HMTA, as it is commercial...

2010
Gisela Winckler Robert Newton Peter Schlosser Timothy J. Crone

[1] Hydrothermal venting along the global mid‐ocean ridge system plays a major role in cycling elements and energy between the Earth’s interior and surface. We use the distribution of helium isotopes along an oceanic transect at 67°S to identify previously unobserved hydrothermal activity in the Pacific sector of the Southern Ocean. Combining the geochemical information provided by the helium i...

2000
SHAO-YONG JIANG

The Sullivan deposit of British Columbia, Canada represents an ancient submarine hydrothermal system that formed a giant Pb-Zn-Ag massive sulfide deposit. Tourmaline is abundant in the deposit and acts as a good tracer that may reveal the nature of the original hydrothermal fluids and ore-forming processes, due to its refractory characteristics. Concentrations of Zr, Hf, Nb, Ta, U and Th in tou...

2009
O. Abramov

Introduction: Impact events locally increase the temperature of a planetary crust, initiating hydrother-mal activity if water or ice is present. Impact-induced hydrothermal activity is responsible for mineralogical-ly and morphologically modifying many terrestrial craters [e.g., 1], and has been suggested for Martian craters [2, 3]. Present-day subsurface ice has been inferred at high latitudes...

2008
Vesselin Dekov Jan Scholten Carl-Dieter Garbe-Schönberg Reiner Botz Javier Cuadros Mark Schmidt Peter Stoffers

[1] An active seafloor hydrothermal system subjects the background sediments of the Grimsey Graben (Tjörnes Fracture Zone) to alteration that produces dissolution of the primary volcaniclastic matrix and replacement/precipitation of sulfides, sulfates, oxides, oxyhydroxides, carbonates and phyllosilicates. Three types of hydrothermal alteration of the sediment are defined on the basis of the do...

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