The resistivity of cement specimens mixedwith carbon fibres under different pressures is studied.Theresults reveal that when pressure becomes larger and larger,
Composite perovskite piezoelectric ceramicsof PMMN quaternary system were prepared by cold-pressingand solid-phase sintering.Piezoelectric modulus and densityof
Structures and hydration activities of alumi-nates CA and CA,of cement minerals are studied by SCF-DV-X<sub>α</sub>method,one of the molecular orbital calculat