Tungsten electrodes

The experiment may also be repeated using a platinum (indicator) electrode and a tungsten wire reference electrode. If the tungsten electrode has been left idle for more than a few days, the surface must be cleaned by dipping into just molten sodium nitrate (CARE ). The salt should be only just at the melting point or the tungsten will be rapidly attacked it should remain in the melt for a few seconds only and is then thoroughly washed with distilled water. 

In a mirror-polished metal electrode substitute for the tungsten electrode we have a smart mirror. A similar photodetector-actuator automatically darkens a smart mirror in a car when a rear car uses high-beam lights. 

The terminal plugs are connected directly to the tungsten electrodes by means of no. 18 copper wire. The latter is coiled... 

Fig. 5. Cyclic voltammograms recorded on a tungsten electrode in 52 m/o AlCl3-NaCl at a sweep rate of 100 mV s-1 and a temperature of 190 °C. The cathodic limit was varied from —0.02 to —0.60 V. Reproduced from Stafford et al. [49] by permission of Elsevier.

The electrochemistry of Ti2+ in 66.7 m/o AlCl3-NaCl has been investigated wherein the electroactive Ti2+ was prepared by the oxidation of Ti metal with liquid A1C13 [176, 185] and by the electrochemical dissolution of titanium metal [120, 177], The authors of both studies concluded that Ti2+ may be oxidized stepwise to Ti3+ and Ti4+ and that both processes are reversible at platinum and tungsten electrodes. However, anomalous voltammetric behavior at high Ti2+ concentrations (greater than 50 mmol L ) suggests the formation of polymeric Ti2+ species in the melt. The reduction of Ti2+ to the metal was not observed at potentials more positive than that required for aluminum deposition. 

Fig. 31. Linear sweep voltammograms recorded at a sweep rate of 100 mV s 1 on a polished tungsten electrode in (---) 66.7 m/o AlCl3-NaCl and (—) 66.7 m/o AlCl3-NaCl containing 225 mmol L 1 Ti2+ at 150 °C [177],...

No effect of the nature of metallic electrodes was found on the tumor destruction,7 38 39 e.g., silver and tungsten electrodes gave results similar to platinum 7 this also means that a slight anodic dissolution of platinum that might occur during the ECT experiment is not responsible for the necrosis of the tumor.7... 

The electrodeposition of zinc on polycrystalline Au, Pt, and tungsten electrodes was preceded by underpotential deposition (UPD) [172]. The formal potential of Zn(II)/Zn(0) couple and diffusion coefficient of Zn(II) were also determined [172]. 

The electrodeposition of zinc on GC, nickel, and tungsten electrodes was investigated in ZnCh - EMIC, and AICI3-EMIC [175,176].Thenucleationon GC required a larger overpotential than on the other used electrodes. The addition of... 

Also, the Pt-Zn electrodeposition on tungsten electrode was studied in ZnCh -EMIC melts containing Pt(II) [185]. The morphology of Pt-Zn alloys is dependent on the deposition potential and Pt(II) concentration in the plating solution. Pt-Zn alloys were also obtained on the electrode surface when Zn( 11) was reduced on Pt electrode. 

A medium-pressure mercury arc lamp consists of a sealed cylindrical quartz tube with tungsten electrodes on each end. The tube contains a small amount of mercury and starter gas (usually argon). An example of such a lamp is in Figure 3.1. ... 

Conventional mercury lamps are essentially sealed quartz tubes with tungsten electrodes at either end. They are filled with mercury metal and vapor and a starter gas (usually argon). When a high voltage is applied across the electrodes, the starter gas is ionized ... 

Finally, a report17 that pure BN nanotubes are formed in an electric discharge between a BN-packed tungsten electrode and a cooled copper electrode extends the list of formal similarities between BN and carbon, and implies that much interesting BN chemistry remains to be discovered. 

Hippocampal slices (400-500 frm) were quickly prepared from male Wistar rats (8- to 9-weeks-old) and maintained in a chamber at 35 °C, where they were continuously perfused with artificial cerebrospinal fluid as described in our previous paper [11]. A bipolar tungsten electrode was placed in the stratum radiatum to stimulate Schaffer collateral and commissural afferents. The evoked potential was extracellularly recorded from the pyramidal cell layer of the CA1 subfield with a glass capillary microelectrode. A single test stimulation (0.05 msec duration) was applied at intervals of 30 sec. Drugs were delivered by perfusion. To induce potentiation of the evoked potentials, tetanic stimulation was applied at the same intensity through the same stimulating electrode as used for the test stimulation. The magnitude of LTP was evaluated by the population spike amplitude 30 min after tetanic stimulation. 

A tungsten electrode inserted at the sensillum base records action potentials fired by two neurons, which can be reliably separated based on amplitude and shape of spikes. Neuron A fires the large spike and responds to stimulation with ethyl acetate. Neuron B (small spikes labeled with dots) does not respond to this odorant. For odor stimulation, air was expelled from a 5 ml syringe laden with 20 pi of odorant, diluted 10-2 in paraffin oil. B The palp carries six classes of ORN with different response spectra. They are consistently housed together as stereotypical pairs in three functional types of sensilla. 

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