No abstract

Effect of the hydrogen radical on the reduction of a silicon tetrachloride (SiCl 4 ) source was studied. The hydrogen radicals were generated using a tungsten (W) filament in a generation chamber, and were remotely supplied to another reaction chamber. The density of the hydrogen radical was estimated from the optical transmittance of 600-nm-wavelength light through phosphate glass doped with tungsten oxide (WO 3 ). Lifetime of the hydrogen radical seemed sufficiently long, and its density as supplied to the reaction chamber was estimated to be on the order of 10 12 cm %3 . Signal intensity of the peak corresponding to SiCl 4 (m/z = 170) detected by quadrupole-mass measurement was confirmed to decrease owing to the reaction with the remotely-supplied hydrogen radical. This indicates the possibility that chemically-stable SiCl 4 , as one of the by-products of the Siemens process, can be reduced to produce silicon.

fracture experiments are conducted for circular plates, vessel endplates and conical frustums of A2017-7075 aluminum alloys and 304 stainless steel, using a testing apparatus developed applying wire-row explosion technique to initiation, where tensile stress waves are generated producing spall in the specimens by the direct incidence of plane detonation waves of the explosive PETN. A VISAR system is adopted to observe the free-surface velocity histories of the specimens. The signals for basic circular plate specimens indicate the characteristics of the failure for tested materials, effects of explosive thickness variations and the configuration of specimens. Hydro codes are satisfactorily applied to simulate the experimental signal data and observed damage phenomena of recovered specimens. Next, an explosive-filled cylindrical vessel with endplate at the one end is initiated at the other end surface and expanded by axially propagating explosive detonation to fracture. Both the VISAR signals and numerical simulation indicate a pullback signal of spallation at the endplate. Finally conic frustums are also loaded by plane detonation, showing different type of spall failure due to the additional reflected waves from the slopping side surfaces.