Normal type tungsten filament for electric lamps

1924 ◽  

Author(s):  
George Christov ◽  
Bolivar J. Lloyd

A new high intensity grid cap has been designed for the RCA-EMU-3 electron microscope. Various parameters of the new grid cap were investigated to determine its characteristics. The increase in illumination produced provides ease of focusing on the fluorescent screen at magnifications from 1500 to 50,000 times using an accelerating voltage of 50 KV.The EMU-3 type electron gun assembly consists of a V-shaped tungsten filament for a cathode with a thin metal threaded cathode shield and an anode with a central aperture to permit the beam to course the length of the column. The cathode shield is negatively biased at a potential of several hundred volts with respect to the filament. The electron beam is formed by electrons emitted from the tip of the filament which pass through an aperture of 0.1 inch diameter in the cap and then it is accelerated by the negative high voltage through a 0.625 inch diameter aperture in the anode which is at ground potential.



2005 ◽  
Vol 879 ◽  
Author(s):  
Scott K. Stanley ◽  
John G. Ekerdt

AbstractGe is deposited on HfO2 surfaces by chemical vapor deposition (CVD) with GeH4. 0.7-1.0 ML GeHx (x = 0-3) is deposited by thermally cracking GeH4 on a hot tungsten filament. Ge oxidation and bonding are studied at 300-1000 K with X-ray photoelectron spectroscopy (XPS). Ge, GeH, GeO, and GeO2 desorption are measured with temperature programmed desorption (TPD) at 400-1000 K. Ge initially reacts with the dielectric forming an oxide layer followed by Ge deposition and formation of nanocrystals in CVD at 870 K. 0.7-1.0 ML GeHx deposited by cracking rapidly forms a contacting oxide layer on HfO2 that is stable from 300-800 K. Ge is fully removed from the HfO2 surface after annealing to 1000 K. These results help explain the stability of Ge nanocrystals in contact with HfO2.





2011 ◽  
Vol 19 (4) ◽  
pp. 341
Author(s):  
Joel Díaz Reyes ◽  
Aarón Pérez-Benítez ◽  
Valentín Dorantes

<span>Tungsten(VI) oxide can be easily synthesized starting from a standard light bulb. The reaction consists in the oxidation at high temperatures (T ≈ 2000 – 3000° C) of a tungsten filament in presence of air; conditions which can be easily achieved by connecting a broken light bulb (but with its intact filament) to an AC-power supply of 110 volts. The vapor of WO3 is condensed into a beaker in a quantity enough to be characterized by infrared spectroscopy. The experiment is very funny, inexpensive and allows to the teacher to link several topics in current chemistry and physics of the tungsten oxides, such as their nomenclature and technological applications (i.e. electrochromic devices, gasochromic sensors, superalloys or as it is used in home: As a “simple” emisor of light!).</span>



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