نتایج جستجو برای: tungsten

تعداد نتایج: 11047  

2014
Anara Molkenova Rozie Sarip Sanjay Sathasivam Polona Umek Stella Vallejos Chris Blackman Graeme Hogarth Gopinathan Sankar

The use of a molecular gold organometallic cluster in chemical vapour deposition is reported, and it is utilized, together with a tungsten oxide precursor, for the single-step co-deposition of (nanostructured) tungsten oxide supported gold nanoparticles (NPs). The deposited gold-NP and tungsten oxide supported gold-NP are highly active catalysts for benzyl alcohol oxidation; both show higher ac...

2003
M. E. Sawan H. Y. Khater H. Iida R. T. Santoro

Precise representation of geometry and energy is essential to properly account for self-shielding effects in tungsten. Up to a factor of 7 overestimation of tungsten decay heat results from homogenization of tungsten and the water cooled heat sink behind it and use of non-selfshielded cross sections in the activation calculations. To correctly estimate tungsten decay heat, 3-D continuous energy...

2011
Jay L. Clausen Benjamin C. Bostick Anthony Bednar Jing Sun Joshua D. Landis

Synchrotron-based X-ray absorption spectroscopy (XAS) of select surface soil samples obtained from Camp Edwards, Massachusetts, small arms ranges indicate that little tungsten metal remains in the soil and that is not stable in the natural environment. X-ray absorption near edge structure (XANES) studies indicate rapid oxidation of tungsten metal to form tungsten oxides W(VI), polytungstates, t...

2008
William R. Wampler

Tungsten is a candidate material for ITER as well as other future magnetic fusion energy devices. Tungsten is well suited for certain hsion applications in that it has a high threshold for sputtering as well as a very high melting point. As with all materials to be used on the inside of a tokamak or similar device, there is a need to know the behavior of hydrogen isotopes embedded in the materi...

2015
P. Fiflis D. N. Ruzic

Determination of the mechanisms underlying the growth of tungsten fuzz is an important step towards mitigation of fuzz formation. Nanostructured tungsten was produced on resistively heated tungsten wires in a helicon plasma source (maximum flux of 2.5× 1021 m−2 s−1). Asymmetry in the setup allows for investigation of temperature and flux effects in a single sample. An effort at elucidating the ...

Journal: :The Biochemical journal 1960
H J Bowen

Tungsten exists at such low concentrations in normal biological material that it has been detected only in tissues from animals previously fed with unusually large quantities of tungsten (Kinard & Van de Erve, 1941), or plants growing in tungsten-rich soils (J. P. R. Polkinhorne, personal communication). In view of the discovery that the related element molybdenum is essential for plants and an...

2003
F. J. Maldonado-Hodar A. F. Perez-Cadenas C. Moreno-Castilla

The morphology of a tungsten-doped monolithic organic aerogel, prepared by the sol–gel method from the polymerisation of a resorcinol, formaldehyde and ammonium tungstate mixture, and of its carbonized derivatives at 500 and 1000 8C was studied by scanning and high-resolution electron microscopy. Tungsten influenced the surface morphology of the carbon aerogels. The tungsten-containing phase wa...

2009
S. Sharafat A. Takahashi Q. Hu

0022-3115/$ see front matter Published by Elsevier doi:10.1016/j.jnucmat.2008.12.318 * Corresponding author. Tel.: +1 310 794 5990; fax E-mail address: [email protected] (S. Sharafat). Bubble growth and gas release during annealing of helium implanted tungsten is described using a Kinetic Monte Carlo approach. Implantation of tungsten with low energy He ions results in the unusual formation of ...

Journal: :Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada 2013
Tea Toplišek Medeja Gec Aljaž Iveković Saša Novak Spomenka Kobe Goran Dražić

In this work, the interactions between tungsten (W) and silicon carbide (SiC) in Sigma SiC fibers at high temperatures were characterized using scanning and transmission electron microscopy. These fibers could have the potential for use in fusion-related applications owing to their high thermal conductivity compared with pure SiC-based fibers. The as-received fibers were composed of a 100-μm-th...

2016
Andrew Bowen

F sharpened tungsten needles are essential tools required for the manipulation of small particles (1, 2, 3). They can be purchased commercially from Fine Science Tools at a cost of roughly $100 for a set of ten needles. Tungsten needles can easily become damaged during routine use, and accidentally bumping the sharpened end of a tungsten needle immediately renders it useless. For laboratories t...

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