Abstract: Disclosed is a transparent plastic sheet obtained by co-polymerizing 100 parts by weight of methyl methacrylate with 0.1 to 2.0 parts by weight of methacrylic acid and 0.1 to 1.5 parts by weight of glycidyl methacrylate, and having a thickness of not greater than 4 inches, wherein the angular deviation satisfies specified conditions according to the thickness of the sheet and wherein the degree of swelling is not greater than 2.50. This transparent plastic sheet shows neither coloring nor sink marks on the surface, has excellent craze resistance and low long-term water absorption percentage, and is hence suitable for use as an aircraft windshield.

Abstract: The invention relates to a CVJ boot in which contact pressure of crest portions closer to a large-diameter mounting portion on the compressed side of a bellows portion is reduced when slant faces forming a root portion of a bending point obtained by the S-shaped bend come into contact with each other, thereby increasing durability.

Abstract: In a particle beam surface analyzer, having a partition wall separation a vacuum space, an opening that is provided in a partition wall through which the particle beam is taken out, a seal member which is moved along a seal surface of the seal member and seals the opening, a condenser lens which converges the particle beam onto the sample, and detector for detecting a physical quantity from the sample when the particle beam is irradiated on the sample, the surface analyzer further has a movable shift member that pushes one side surface of the seal member along the seal surface of the seal member and a stopping member which the other side surface of the seal member having a predetermined angle being larger than 55.degree. and smaller than 75.degree.

Abstract: A method of machining a diamond workpiece by a laser beam in which a metallic membrane or layer is formed on at least one surface of the workpiece before the workpiece is subjected to the machining operation. The metallic membrane or layer is preferably formed on both side surfaces of a plate-like diamond workpiece. The workpiece machined according to the present invention has a good appearance without cracks and splinters, and a smooth cut surface.

Abstract: To obtain linear characteristics between transmittable torque and differential speed between the two rotary members in the viscous coupling apparatus including a working chamber filled with a viscous fluid and first and second plural annular resistance plates fixed to the first and second rotary members, respectively, at least one of the annular resistance plates is formed with plural blades to agitate the viscous fluid within the working chamber. The blades can be formed by forming a plurality of cutouts in the annular resistance plate in the vortical arrangement manner and then bending the edge of each cutout therealong.

Abstract: A control circuit for a brushless electric motor includes a pulse width modulator for applying drive signals to a gate drive circuit according to from a current amplifier, multi-phase drive coils connected to the gate drive circuit through an inverter circuit, a comparator connected to the current amplifier, a flip-flop for applying output signals from the comparator and drive signals form the pulse width modulator, and a circuit portion for applying signals for switching the direction of rotation from the flip-flop to the gate drive circuit. A preceding signal for switching the direction of rotation is maintained in the flip-flop until the dead zone of the pulse width modulating circuit is elapsed and a new signal for switching the direction of rotation is generated in synchronism with a pulse signal produced by the pulse width modulating circuit so as to be supplied to the gate drive circuit.