Abstract: A method of growing a crack-free single crystal is disclosed which comprises heating raw materials in a crucible to thereby obtain a melt of the raw materials, contacting a lower end of a seed crystal with the melt and pulling the seed crystal to thereby grow a single crystal, and wherein the melt of the crucible flows from its surface toward its inner part inside the crucible by convection at a position locating outside a region where the growth of the single crystal occurs. This flow control can be achieved by, for example, surrounding the crucible with a heat insulation refractory composed of a pair of semicylindrical refractories disposed so as to provide a circular cross section with differently sized gaps. In the above-mentioned method, the seed crystal may be rotated during a shoulder growth in which the single crystal has its diameter increased from that of the seed crystal to a target diameter at a rotation rate greater than that during a subsequent cylindrical body growth.

Abstract: A method of growing a single crystal of a rare-earth silicate is disclosed which comprises heating raw materials in a crucible to thereby obtain a melt of the raw materials, contacting a lower end of a seed crystal with the melt and pulling the seed crystal to thereby grow a single crystal, and wherein the pulling is conducted along an axis of pulling having a gradient of at least 30.degree. from the b-axis ([010] axis) of the single crystal and a gradient of at least 25.degree. from the c-axis ([001] axis) of the single crystal. The invention also provides a method of machining a single crystal of a rare-earth silicate into a cylindrical form, comprising grinding a cylinder whose axis is directed so as to have a gradient of 0.degree. to 65.degree. from the c-axis ([001] axis) of the single crystal.

Abstract: A single crystal scintillator and apparatus for prospecting underground strata using the scintillator is described. The single crystal scintillator is a cerium doped gadolinium silicate compound of the formula:Gd.sub.2-(x+y) Ln.sub.x Ce.sub.y SiO.sub.5wherein Ln is Sc, Tb, Lu, Dy, Ho, Er, Tm, or Yb; 0.03.ltoreq.x.ltoreq.1.9; and 0.001.ltoreq.y.ltoreq.0.2.

Abstract: Properties of a compound semiconductor single crystal (e.g. GaAs single crystal) can be homogenized by subjecting the single crystal covered with a metal oxide powder (e.g. Ga.sub.2 O.sub.3 powder) to a heat treatment.

Abstract: In an engine idling speed control system for an internal combustion engine, by feedback controlling increasingly or decreasingly, the amount of intake air fed to the engine with a controlling value variable in accordance with a difference between an actual engine speed and a desired idling speed so as to control the engine to drop speed to the desired idling speed, decreasing variations of the controlling value are restricted to a limit value which is higher when the vehicle is running at a speed higher than a predetermined vehicle creeping speed than when at a running speed lower than the predetermined vehicle creeping speed.

Abstract: A radiation detector containing as a scintillator a combination of two or more single crystals of cerium doped gadolinium silicate having different Ce concentrations, or a single crystal of cerium doped gadolinium silicate having different Ce concentrations therein, is improved in a spatial resolution and a time resolution.

Abstract: A scintillator for radiation detection obtained by coating a light reflective material in a thickness of 50 to 150 .mu.m by a screen printing method on the surface of a solid scintillator material substrate is excellent in uniformity, dimensional accuracy with high light output. When the light reflective material layer is covered with a synthetic resin film, adhesive strength of the light reflective material layer to the substrate is increased remarkably.