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We examined the influence of 1ϫ1 defects at the Si(111)7ϫ7 surface on the Schottky barrier height ͑SBH͒ of the Ag/Si interface. By quenching samples from high temperatures, we intentionally introduced 1ϫ1 defects on Si͑111͒ 7ϫ7 surfaces. After characterizing the area of the 1ϫ1 defects by scanning tunneling microscope, we deposited Ag films in situ at room temperature on the surfaces and measured the SBH. As the 1ϫ1 area increased from 0 to 50 %, SBH increased from 0.60 eV to 0.66 eV. The 1ϫ1 area dependence of the SBH was caused by a locally high SBH in the 1ϫ1 area with the pinch-off area extending around it.

With the intention to prove the possibility of applying the Diels-Alder reaction to trap a trace amount of residual styrene monomer in polystyrene, a model reaction between cyclopentadiene with styrene in a dilute o-chlorobenzene solution was carried out. In the presence of an excess amount of dicyclopentadiene, the consumption of styrene was measured with time lapse by means of gaschromatography. At temperatures ranging from 140 to 220°C, the amount of styrene was observed to decrease remarkably until it reached an equilibrium concentration. The higher the temperature was, the higher the equilibrium concentration became. The equilibrium constants at each temperature and the activation energy for the reaction were calculated.0250-9733/8