Abstract: Curable polymer mortar or concrete compositions with improved workability and processability use polymerizable liquid resin composed of unsaturated urethane of a specified form and vinyl monomers as binder and also contain an inorganic powder filler, aggregates and a viscosity reducer of a specified kind and a low shrinking agent of a specified kind each at a specified rate. Cured compositions with improved accuracy in measurements, strength and water absorption can be obtained from such compositions. Self-leveling property can also be provided.

Abstract: A Gunn diode in which the conversion efficiency can be improved without lowering the reliability, by reducing the dead zone while maintaining n.sup.+ nn.sup.+ structure. In this Gunn diode, the donor impurity concentration in the n-type active layer is graded along a direction perpendicular to a contact plane between the n-type active layer and the n.sup.+ -type layers, and an average concentration gradient of the donor impurity concentration in the n-type active layer simultaneously satisfies the following two inequalities: G>(A.sub.1 N/L)exp(-NL/S.sub.1) and G<(A.sub.2 N/L)exp(-NL/S.sub.2), where L is a thickness of the n-type active layer, N is an average concentration of the donor impurity, S.sub.1 =0.87.times.10.sup.12 cm.sup.-2 is a constant, S.sub.2 =1.32.times.10.sup.12 cm.sup.-2 is a constant, A.sub.1 =2.0 is a constant, and A.sub.2 =9.0 is a constant.