Abstract: Disclosed are semiconductor devices in which an electrical insulating substrate is made of a sintered silicon carbide body having thermal conductivity of at least 0.4 cal/cm.multidot.sec.multidot..degree.C. at 25.degree. C., electrical resistivity of at least 10.sup.7 ohm.multidot.cm at 25.degree. C. and coefficient of thermal expansion of 3.3.about.4.times.10.sup.-6 /.degree.C. at 25.degree. C. to 300.degree. C.

Abstract: A sintered silicon carbide body having a high thermal conductivity and a high electrical insulation without any drop substantially throughout the sintered body is produced from a powdery silicon carbide composition comprising at least 90% by weight of silicon carbide powders having an average particle size of not more than 10 .mu.m and 0.01 to 4% by weight of powders of beryllium or its compound having a particle size of not more than 30 .mu.m in terms of beryllium atom, a nitrogen content of the composition being not more than 500 ppm.

Abstract: A silicon carbide sintered body comprising silicon carbide as principal constituent, a first component for providing electrical insulating properties to said silicon carbide, said first component comprising at least one of metallic beryllium, beryllium compounds, boron and boron compounds and contained in a total amount of 0.01 to 3.5% by weight calculated as metal, and a second component which can further promote said silicon carbide sinterability provided by said first component and which does not diffuse easily in the particles of said silicon carbide, said second component comprising at least one substance selected from the Group I elements exclusive of hydrogen and francium, Group II elements exclusive of beryllium, radium and mercury, Group III elements exclusive of boron and aluminum, Group IV elements exclusive of carbon, Group V elements, Group VIa elements, Group VIIa elements Group VIII elements exclusive of iron, and compounds thereof, and contained in a total amount of 0.

Abstract: Sintered aluminum nitride having a high thermal conductivity, which comprises at least 65% by weight of aluminum nitride, and at least one of beryllium, a beryllium compound, lithium and a lithium compound, and a semi-conductor device using the same.

Abstract: A coordinate reading apparatus for reading positions on a tablet, having magnetic-field generating coils, with a magnetic-field detector. The magnetic-field detector produces an analog electric signal corresponding to a desired position to be read on the tablet in response to the magnetic fields induced by the magnetic-field generating coils. The analog electric signal generated by the detector is composed of both a fundamental wave component signal and an n-th order harmonic wave component signal (n being an integer equal to or larger than 2). A processing unit for receiving the analog electric signal from the magnetic-field detector and produces coordinate data corresponding to the desired position to beread on the tablet by analyzing a first rotating magnetic-field vector induced by the fundamental wave component signal and a second rotating magnetic-field vector induced by the n-th order harmonic wave component signal.

Abstract: From 0.1 to 3.5% by weight of beryllium oxide powder, calculated as beryllium, is added to silicon carbide powder containing up to 0.1% by weight of aluminum, up to 0.1% by weight of boron and up to 0.4% by weight of free carbon, and the mixed powder is pressure-molded. The resulting molded article is heated to a temperature of 1,850.degree. C. to 2,500.degree. C. till there is obtained a sintered body having at least 90% relative density of silicon carbide. Thus, the sintered body having thermal conductivity of at least 0.4 cal/cm.sec..degree. C. at 25.degree. C., electrical resistivity of at least 10.sup.7 Ohm.cm at 25.degree. C. and coefficient of thermal expansion of 3.3.about.4.times.10.sup.-6 /.degree.C. at 25.degree. C. to 300.degree. C. can be obtained.