نتایج جستجو برای: tungsten

تعداد نتایج: 11047  

2018
S. Ichijo K. Tamura T. Takano A. Nakao T. Hirahara

In forming tungsten carbide layer by low temperature and vacuum CVD, uniformity of film thickness, adhesion and gloss achieved when the effective zone of coating set is increased to 4450 x 1,100mm is described. Characteristics of tungsten carbide layer are evaluated and compared with other materials. Some practical applications to the mechanical parts of plastic injection molding machines are i...

Journal: :Chemical communications 2015
Bora Seo Hu Young Jeong Sung You Hong Alla Zak Sang Hoon Joo

Tungsten oxide/tungsten sulfide (W18O49@WS2) core-shell nanorods prepared via a controlled sulfidization reaction of W18O49 nanowhiskers showed hydrogen evolution reaction (HER) activity superior to WS2 nanotubes, indicating the critical role of a highly conductive oxide core in enhancing HER activity.

Journal: :Nanoscale 2012
Xiangpeng Fang Bingkun Guo Yifeng Shi Bin Li Chunxiu Hua Chaohua Yao Yichi Zhang Yong-Sheng Hu Zhaoxiang Wang Galen D Stucky Liquan Chen

Ordered mesoporous tungsten-doped MoO(2) was synthesized by a nanocasting method. The Li storage performance of mesoporous MoO(2) is significantly improved by tungsten doping, which exhibits a reversible capacity of 700 mA h g(-1), better cycling and rate performance. This material combines the advantages of the high theoretical capacity of MoO(2) and the better electroactivity of WO(2).

Journal: :The Science of the total environment 2008
Vernon G Thomas Ian R McGill

The rates of dissolution of copper, tin, and iron from sintered tungsten-bronze spheres (51.1%W, 44.4%Cu, 3.9%Sn, 0.6%Fe, by mass) were measured in an in vitro simulated avian gizzard at pH 2.0, and 42C. Most of the spheres had disintegrated completely to a fine powder by day 14. Dissolution of copper, tin, and iron from the spheres was linear over time; all r>0.974; all P<0.001. The mean rate ...

2003
A. F. Pérez-Cadenas C. Moreno-Castilla F. J. Maldonado-Hódar

Tungsten catalysts supported on activated carbon were prepared using tungsten hexacarbonyl, ammonium tungstate, and tungsten pentaethoxide. The catalysts were pretreated in He, dry air, or wet air at 623 K for 6 h before being characterized by N2 adsorption at 77 K, temperature-programmed desorption, X-ray diffraction, high-resolution transmission electron microscopy, and X-ray photoelectron sp...

2013
Taejin Kim Andrew Burrows Christopher J. Kiely Israel E. Wachs

A series of model-supported WO3 catalysts were synthesized on preformed Al2O3, Nb2O5, TiO2, and ZrO2 supports by impregnation of aqueous ammonium metatungstate, (NH4)10W12O41·5H2O. The molecular and electronic structures of the supported tungsten oxide phases were determined with in situ Raman and UV–vis spectroscopy, respectively. The supported tungsten oxide structures are the same on all oxi...

2008
T. Nakano H. Kubo N. Asakura K. Shimizu S. Higashijima

Two studies are included: tungsten accumulation in the main plasma and radiation processes of carbon ions in the detached plasma of JT-60U. [Tungsten] It has been found that tungsten accumulation becomes more significant with increasing plasma rotation velocity against the plasma current direction, where negative radial electric field is formed. The accumulation level does not depend on the tun...

Journal: :Angewandte Chemie 2013
Jieun Yang Damien Voiry Seong Joon Ahn Dongwoo Kang Ah Young Kim Manish Chhowalla Hyeon Suk Shin

Composite materials: Tungsten disulfide and WS2 /reduced graphene oxide (WS2 /rGO) nanosheets were fabricated by hydrothermal synthesis using tungsten chloride, thioacetamide, and graphene oxide (GO) as starting materials. The WS2 nanosheets are efficiently templated on the rGO layer. The WS2 /rGO hybrid nanosheets show much better electrocatalytic activity for the hydrogen evolution reaction t...

2006
Raman Ganesan Jae Sung Lee

Tungsten trioxide microspheres of 2–4 m diameter have been prepared by controlled oxidation of tungsten carbide microspheres. These microspheres are characterized by XRD, SEM, and HRTEM. The microspheres are made of WO3 nanoparticles with an average diameter of around 15 nm. Platinum supported on these WO3 microspheres exhibits higher and stable electrocatalytic activity for methanol oxidation ...

2014
Amine Samoudi Karen Van Audenhaege Günter Vermeeren Micahel Poole Luc Martens Roel Van Holen Wout Joseph

INTEC, Ghent University/iMinds, Ghent, Belgium Combining Single Photon Emission Computed Tomography (SPECT) with Magnetic Resonance Imaging (MRI) results in an interaction of the time-varying magnetic field gradients with the highly conducting tungsten collimator, which generates a secondary magnetic field causing spatial distortions in reconstructed MR images. Accurate simulations are importan...

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