TaC-Ni オヨビ TaC-Ni-Moケイサーメット ノ ショウケツ ト ビサイコウゾウ ノ カンサツ

TaC-Ni and TaC-Ni-Mo cermets were sintered at 1150～1400℃ in a vacuum of 5×10^ Torr for 1hr. The effect of addition of molybdenum on the sinterability and the microstructure of TaC-base cermets were studied by measurments of relative density and micro・Vicker\u27s hardness and Auger electron microscopy. Relative densities and hardness of the TaC-Ni-Mo cermets were higher than these of the TaC-Ni cermets. In TaC-Ni-Mo cermets, liquid phase appeared relatively lower temperature (1150～1250℃) than in TaC-Ni cermet (about 1290℃) and it is estimated that the wettability between solid and liquid phases is so improved that the grain growth of TaC is suppressed. It was obsreved that all molybdenum resolves to nickel phase and TaC silghtly resolves to nickel or Ni-Mo phase

First Total Synthesis of (–)-Merrillianin

The first total synthesis of (–)-merrillianin (1), which is a natural sesquiterpene with a tri- fused structure having a cyclopentane ring and five- and seven-membered lactone parts, is demonstrated. This asymmetric total synthesis enabled the absolute stereo structure determination of naturally occurring (–)-1