Nemst glower

Light sources can either be broadband, such as a Globar, a Nemst glower, an incandescent wire or mercury arc lamp or they can be tunable, such as a laser or optical parametric oscillator (OPO). In the fomier case, a monocln-omator is needed to achieve spectral resolution. In the case of a tunable light source, the spectral resolution is detemiined by the linewidth of the source itself In either case, the spectral coverage of the light source imposes limits on the vibrational frequencies that can be measured. Of course, limitations on the dispersing element and detector also affect the overall spectral response of the spectrometer. 

Radiation in the infrared region of the spectrum is obtained from heated ceramic devices such as the Nemst glower or Globar. The Globar is made of silicon carbide and is heated to approximately 800-1500°C to emit black-body radiation in the infrared region of the spectrum. Coils of nichrome wire also emit infrared radiation when electrically heated. 

Black body radiators are used as sources of infrared radiation in the range 2-15 yum, e.g. the Nemst glower, which consists of a hollow rod made of the fused oxides of zirconium, yttrium and thorium. For use it is preheated and, when a voltage is applied, it emits intense continuous infrared radiation with very little visible radiation. 

A Nemst glower is an obsolete infrared source that consists of a ceramic bar (90 mass% Zr02 7% Er203 7% Y203) operated between 1000°C and 2000°C. 

Figure 7 Ar matrix of Cr(CO)g doped with H2. Solid lines represent spectrum after broad band irradiation followed by irradiation through cobalt glass. Dashed bnes represent the spectrum of the same matrix after 90 min irradiation with the visible light from a Nemst glower. Band assignments 1, Cr(CO)5(H2) 11, Cr(CO)4(H2)2 III, Cr(CO)4(H2) 6, Cr(CO)6 5, CrjCOjs. (Reprinted with permission from Ref. 99. 1985 American Chemical Society)...

Nemst glower A source of infrared radiation that consists of a cylinder of zirconium and yttrium oxides heated to a high temperature by passage of an electrical current. 

Reagents i, U.v. photolysis ii, Nemst-glower photolysis ( > 320nm) iii, annealing matrix ... 

The Nemst glower is a cylindrical bar composed of zirconium oxide, cerium oxide, and thorium oxide that is heated electrically to a temperature between 1500 and 2000 K. The source is generally about 20 mm long and 2 mm in diameter. The rare earth oxide ceramic is an electrical resistor passing current through it causes it to heat and glow. 

Figure 1. Experimental apparatus for spectrometric detection of electron beam induced reactions. Upper portion of figure describes infirared spectrometer while lower portion describes electron beam gun and vacuum chamber. NG = Nemst glower Ch = chopper RR = reflectance reference RS = reflectance sample M monochrometer, CP =...

A significant step forward was achieved by Viengerov in 1938 He used blackbody infrared sources, (such as Nemst glowers) for radiation input and a microphone to detect the acoustic signal. His goal was the analysis of gas mixtures with a photoacoustic device. The sensitivity of the analysis was limited by the background noise which is produced by absorption of radiation in the cell... 

Wagner C (1943) On the mechanism of the electrical current conductivity in the Nemst glower (in German). Naturwiss 31 265-268... 

Coil of Nichrome wire, or Nemst Glower, or Globar. 

A. Infrared (Globar, Nemst glower, Nichrome wire, tunable las )... 

All IR spectrometers have a source of infrared radiation which is usually some solid material heated to incandescence by an electric current. The Nemst Glower is a source composed mainly of oxides of rare earths such as zirconium, yttrium and thorium, and the Globar is a silicon carbide rod. Other materials have been used as well. All these sources are fairly efficient emitters of infrared radiation and approach the energy distribution of a theo-rectical black body. 

The solid oxide fuel cell (SOFC) has also been the object of research for many years. Its development can be traced back to the Nemst Glower of 1899. Since the SOFC is a solid-state device, it has many advantages from the point of view of mechanical simplicity. The SOFC is also very flexible in the way it can be made, and its possible size. It therefore has scope for a wide variety of applications. SOFCs can be made from a range of different materials, with different operating temperatures, from about 650 to 1000°C. These issues are described in Section 7.5. 

The SOFC was derived from the Nemst glower, originally intended as a commercial light source to replace caibon filament lamps at the end of the last centniy. This device made nse of the Nemst mass composed of yttria-stabilized zirconia (YSZ), a predominantly ionic... 

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