In order to obtain single crystals of SnO2 which can be used for the investigation of the intrinsic electrical and other related properties, crystal growth by the method using the vapor reaction of SnCl4 with H2O was attempted, and was successfully performed. Colorless transparent single crystals with sizes up to 2×5×15 mm could be obtained by 24 hr run at 1300°C. The measurements of crystallographic properties, optical transmission, electrical conductivity and Hall effect were carried out with the grown single crystals. The crystals were found to be twins having {011} twinning plane. It was shown that the crystal is a typical n-type broad-band semiconductor having the value of the conductivity of a few Ω-1·cm-1 and the mobility of about 200 cm2·volt-1·sec-1 at room temperature. The mobility of the crystals was found to change by the equation µ∝T -2 above 250°K.

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The gamma-ray blazar 1611+343 was observed with polarization VLBI mode at 5 GHz in February 1999. The total intensity (I) VLBI image of the source shows a core-jet structure. The jet bends eastward at ∼ 3 mas south of the core. Four components have been detected from results of fitting, with apparent speeds estimated at 6.7 ± 0.7, 2.5 ± 0.3, 4.5 ± 0.5 h −1 c for three jet components (taking H 0 = 100 h km s −1 Mpc −1 , q 0 = 0.5). The polarization (P ) VLBI image of 1611+343 displays the polarized configuration in the jet. The mechanism of the curved jet is discussed.