IX. A Volumetric Determination of Tungsten in Tungsten Stell and Ferrotungsten

Determination of the electron–phonon coupling constant in tungsten

Seed growth of tungsten diselenide nanotubes from tungsten oxides.

We report growth of tungsten diselenide (WSe2) nanotubes by chemical vapor deposition with a two-zone furnace. WO3 nanowires were first grown by annealing tungsten thin films under argon ambient. WSe2 nanotubes were then grown at the tips of WO3 nanowires through selenization via two steps: (i) formation of tubular WSe2 structures on the outside of WO3 nanowires, resulting in core (WO3)-shell (...

The determination of tungsten in biological material by activation analysis.

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...

Tungsten coil atomic emission spectrometry: calcium determination in biodiesel samples

In this application note, tungsten coil atomic emission spectrometry was used for direct determination of Ca in biodiesel samples. Discrete volumes of biodiesel (10 μL) were directly placed on the tungsten coil with a micropipette and an appropriated heating program was applied to decompose the samples. The first four heating steps (0.32; 0.35; 0.36 and 0.37 V for 20; 50; 50 and 50 s, respectiv...

Tungsten Toxicity in Plants.

Tungsten (W) is a rare heavy metal, widely used in a range of industrial, military and household applications due to its unique physical properties. These activities inevitably have accounted for local W accumulation at high concentrations, raising concerns about its effects for living organisms. In plants, W has primarily been used as an inhibitor of the molybdoenzymes, since it antagonizes mo...