Abstract: A .sup.99m Tc-labeled radioactive diagnostic agent being useful for visualization and dynamic inspection of hepatobiliary ducts and having a high stability and no material toxicity, which comprises .sup.99m Tc in the form of pertechnetate and a non-radioactive carrier, the non-radioactive carrier comprising an N-pyridoxyl-.alpha.-amino acid of the formula: ##STR1## wherein R.sup.1 and R.sup.2 are each an atom or an atomic group present in the .alpha.-amino acid residue encompassed by the dotted line and R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are each a hydrogen atom, a halogen atom, a C.sub.1 -C.sub.10 alkyl group or a C.sub.1 -C.sub.10 alkyl group substituted with at least one hydrophilic group or its salt, and a reducing agent for pertechnetate.

Abstract: A method for manufacturing power switching devices such as thyristors and power transistors comprising the steps of forming impurity diffused layers of one conductivity type and of the opposite conductivity type in a semiconductor substrate of one conductivity type; forming a film containing phosphorus on the substrate; diffusing lifetime killer atoms into the substrate; and forming electrodes on the substrate.

Abstract: A compression type semiconductor device includes a semiconductor element; at least one metal plate having substantially upright edge surfaces, a planar contacting surface engaging a first surface of the semiconductor element and a continuous curved surface interconnecting the edge surfaces and the contacting surface; and a means for pressing the contacting surface of the metal plate against the first surface of the semiconductor element. The continuous curved surface of the metal plate is so formed that at each point on the periphery of the contacting surface at least one plane normal to the contacting surface intersects the curved surface in an arcuate curve which tangentially joins the contacting surface.

Abstract: A gate turn-off thyristor which comprises a semiconductor body having at least four contiguous layers, namely, a first layer of a first conductivity type, a second layer lying continguous to the first layer and having a second conductivity type, a third layer lying contiguous to the second layer and having said first conductivity type, and a fourth layer contiguous to the third layer and having said conductivity type;an anode electrode mounted on said first layer;a gate electrode formed on said third layer; anda cathode electrode deposited on said fourth layer, and in which the following two relations are satisfied:.rho..multidot.V.sub.j /.rho..sub.sb .gtoreq. 10.5(v.multidot.cm) and .rho..sub.sb .ltoreq. 35 (.OMEGA./ )where .rho..sub.sb = sheet resistance (.OMEGA./ ) at the normal temperature of the third layer, V.sub.j = backward withstanding voltage (V) at a PN junction bertween the third and fourth layers, and .rho. = specific resistance (.OMEGA..multidot.cm) of the second layer.