Abstract: The invention relates to a method of producing imide bond-containing compounds and flame retardants comprising such compounds. The method comprises reacting an acid anhydride with an isocyanate compound in an inert solvent in the presence of a tertiary amine as catalyst. The imide bond-containing compounds thus obtained provide flammable substances with good flame resistance and at the same time themselves have good heat resistance and weather resistance. Therefore, the flame retardants comprising such compounds have a wide field of application.

Abstract: Superconductors of the Bi-Pb-Sr-Ca-Cu-O system and Tl-Pb-Ba-Ca-Cu-O system having a high Tc phase (about 110K and about 125K, respectively, or more) at a high proportion are obtained by adding a calcium compound which forms CaO and a liquid phase at a temperature for firing the superconductors, e.g., Ca.sub.2 PbO.sub.x (x=3 or 4); or by starting form a composition represented by the formula: Bi.sub.2 Pb.sub.(n-1)/2 Sr.sub.2 Ca.sub.n Cu.sub.n+1 O.sub.b, or Tl.sub.2 Pb.sub.(n-1)/2 Ba.sub.2 Ca.sub.n Cu.sub.n+1 Ob where 2.ltoreq.n.ltoreq.10, 5.ltoreq.b.ltoreq.40.5, i.e., at a ratio of Ca:Pb=2:1.

Abstract: The invention relates to a method of producing imide bond-containing resins and flame retardants comprising such resins. The method comprises reacting a halogenated phthalic anhydride, a specific copolymer and a diisocyanate compound in an inert solvent in the presence of a tertiary amine as a catalyst to give an imide bond-containing resin. The resins provide flammable substances with good fire or flame resistance and at the same time themselves have good heat resistance and weather resistance. Therefore, the flame retardants comprising these resins have a wide field of application.

Abstract: A coolant for use in cryogenic devices of closed cycle system which comprises a mixture of a liquid nitrogen and a fluorocarbon of the formula: C.sub.n F.sub.2n+2, wherein n is an integer of 2 to 4. The coolant, when used to cool heat generating semiconductor devices and other devices to a cryogenic temperature, exhibits an increased heat flux and thus an increased cooling capability, in addition to a simple and small structure of the cooling system, and a prevention of environmental pollution.

Abstract: A method for producing a ceramic circuit board comprising the steps of (i) forming a conductor portion of the ceramic circuit board by printing a conductive paste composition on a ceramic base plate for the circuit board and then (ii) firing the ceramic base plate and the conductive paste composition together, wherein a copper-base composition comprising a copper powder and 0.5 to 5 parts by weight, based on 100 parts by weight of copper powder, of at least one organo metallic compound capable of forming an inorganic compound or compounds, respectively, when fired in an inert atmosphere, is used as the conductive paste composition.The combined use of isopropyl tridodecylbenzene sulfonyl titanate and isopropyl triisostearoyl titanate greatly improve the flowability of the copper-base conductive paste composition.

Abstract: A multi-layer superconducting circuit substrate, including insulating layers, and interconnection patterns of a superconductive ceramic material located between the insulating layers, the patterns of the superconductive ceramic material being connected via through-holes of the superconductive ceramic material, is provided. The patterns of the superconductive ceramic material are preferably encapsulated with a metal of gold, silver, platinum or an alloy thereof.

Abstract: The invention relates to a method of producing imide bond-containing resins and flame retardants comprising such resins. The method comprises subjecting a halogenated phthalic anhydride, a specific copolymer and a diamine to dehydration reaction in an inert solvents to give an imide bond-containing resin. The resins provide flammable substances with good fire or flame resistance and at the same time themselves have good heat resistance and weather resistance. Therefore, the flame retardants comprising these resins have a wide field of application.

Abstract: A method for producing a multilayer ceramic circuit board including the steps of forming a multilayer structure consisting of patterns of copper-based paste and glass-ceramic layers, the glass-ceramic layers consisting of a mixture of 10 percent to 75 percent by weight of .alpha.-alumina, 20 percent to 60 percent by weight of crystallizable or noncrystallizable glass which can be sintered at a temperature lower than the melting point of copper, and 5 percent to 70 percent by weight of quartz glass, based on the total weight of the glass-ceramic, blended with a binder containing a thermally depolymerizable resin; prefiring the multilayer structure in an inert atmosphere containing water vapor, the partial pressure of which is 0.005 to 0.3 atmosphere, at a temperature where the thermally depolymerizable resin is eliminated; and firing the multilayer structure in an inert atmosphere containing no water vapor at a temperature below the melting point of copper so as to sinter the glass-ceramic.

Abstract: An evaporation cooling module for cooling plural semiconductor chips bonded on circuit boards immersed in a coolant within the module employs immersed heat exchangers associated with bubble traps which trap gaseous bubbles of evaporated coolant and maintain same in contact with the heat exchanger for improved reliquification efficiency. Bubble guides, which may be mounted to the circuit boards intermediate vertically spaced rows of semiconductor chips, guide gaseous bubbles of the evaporated coolant to the bubble trap, producing local convection coolant currents affording increased reliquification efficiency by released gases and improved temperature uniformity of the plural semiconductor chips. Use of immersed heat exchangers avoids decrease in reliquification efficiency since isolated therefrom. Bubble traps of predetermined porosity permit preferential separation of gaseous bubbles of the evaporated coolant and the undesired released gases.

Abstract: A method for producing a multilayer ceramic circuit board including the steps of forming a multilayer structure consisting of patterns of copper-based paste and glass-ceramic layers, the glass-ceramic layers consisting of a mixture of 10 percent to 75 percent by weight of .alpha.-alumina, 20 percent to 60 percent by weight of crystallizable or noncrystallizable glass which can be sintered at a temperature lower than the melting point of copper, and 5 percent to 70 percent by weight of quartz glass, based on the total weight of the glass-ceramic, blended with a binder containing a thermally depolymerizable resin; prefiring the multilayer structure in an inert atmosphere containing water vapor, the partial pressure of which is 0.005 to 0.3 atmosphere, at a temperature where the thermally depolymerizable resin is eliminated; and firing the multilayer structure in an inert atmosphere containing no water vapor at a temperature below the melting point of copper so as to sinter the glass-ceramic.

Abstract: A method for producing a multilayered glass-ceramic structure with copper-based conductors therein, includes firing a multilayered structure, in which copper-based patterns and glass-ceramic layers are alternately laminated, in an inert atmosphere containing water vapor, the partial pressure of which is from 0.005 to 0.3 atmosphere. The temperature multilayered structure is fired at a temperature at which a thermally depolymerizable resin binder, contained in the glass-ceramic green sheets, is depolymerized and eliminated, but its glass components and the copper exhibit substantially no change in their state. The method also includes raising, in an inert atmosphere without water vapor, the firing temperature at which particles of the glass components coalesce, but the metallic state of copper is not affected.

Abstract: A ceramic substrate, suitable for use as a circuit substrate on which integrated circuit chips are bonded, which consists essentially of, based on the weight of the substrate, 0.5.about.5.0% by weight of MgO, and 95.0.about.99.5% by weight of the total of Al.sub.2 O.sub.3 and SiO.sub.2, the proportion of the Al.sub.2 O.sub.3 to the SiO.sub.2 being in the range from 50:50 to 80:20 by weight.

Abstract: A method of forming a ceramic circuit substrate allowing mounting of high integration density semiconductor elements. The method provides a multilayered ceramic circuit substrate having via holes formed with high accuracy and high integration density wiring patterns by forming metallic conductive balls to connect the conductive wiring patterns of upper and lower layers; a ball arranging plate having many holes placing on a green sheet uniformly in close contact; filling the holes of the plate with the embedding the conductive balls by pressure into the green sheet; and thereafter baking the green sheet individually or in a stacked layered arrangement.

Abstract: A multilayer circuit board (10) for putting semiconductor devices thereon consists of conductor layers (6, 60, 61, 62, 63) made of a metal selected from the group consisting of Au, Ag, Cu and an alloy thereof, insulating material (2, 7) made of glass-ceramic and an alumina sintered plate (1). The glass-ceramic is comprised of borosilicate glass and alumina and has a low dielectric constant and a thermal expansion coefficient approaching that of the semiconductor devices. The alumina sintered plate (1) is placed between the ground and supply voltage conductor layers (62, 63) and the signal conductor layers (60).

Abstract: In a method of manufacture of a multilayer ceramic board, a conductor land is formed and baked on a first substrate. A second substrate on which the wiring pattern is formed is then electrically connected to the first substrate via the land. An error in the substrate due to shrinkage at the time of sintering is thereby compensated by the conductor land. This assures the formation of a highly accurate wiring pattern on the sintered substrate surface, despite shrinkage of the ceramic during sintering of the raw sheets of ceramic.