Abstract: In a direct fuel injection diesel engine having a piston with a pentroof-shaped top face, with regard to a pentroof-shaped piston (13) with a cavity (25) recessed in a central part of the top face, a radial width S of a squish area (26) formed between an outer peripheral part of the top face and a lower face of a cylinder head (14) changes in the circumferential direction of the piston (13). By setting a squish clearance H large for a portion where the radial width S of the squish area (26) is large and setting the squish clearance H small for a portion where the radial width S of the squish area (26) is small, more specifically, by setting S/H so that it is constant in the circumferential direction, it is possible to make the strength of the squish flow uniform in the circumferential direction of the piston, thus promoting the mixing of air and fuel and reducing harmful exhaust components.

Abstract: In a direct fuel injection diesel engine equipped with a pentroof-shaped piston, a collision angle (?) at which fuel injected in a direction in which the height of the top face of a piston (13) is high collides with a cavity (25) is set larger than a collision angle (?) at which fuel injected in a direction in which the height of the top face of the piston (13) is low collides with the cavity (25).

Abstract: A power conversion system for converting a dc voltage to a pulsed ac voltage includes a dc voltage source providing three or more electric potentials, and a switching circuit arranged to connect one of the potentials selectively to an output terminal. A controller produces a pulsed ac output voltage at the output terminal from the potentials of the dc voltage source by controlling an on time for connecting each of the potentials to the output terminal.

Abstract: A power conversion system for converting a dc voltage to a pulsed ac voltage includes a dc voltage source providing three or more electric potentials, and a switching circuit arranged to connect one of the potentials selectively to an output terminal. A controller produces a pulsed ac output voltage at the output terminal from the potentials of the dc voltage source by controlling an on time for connecting each of the potentials to the output terminal.

Abstract: It is an object of the present invention to provide immunopotentiators and immunotherapeutic formulations available at low cost and having a benign side effect profile. According to the present invention, an LAK activity enhancer containing an extract of Lentinus edodes mycelium and an LAK activity-enhancing formulation containing said enhancer are provided.

Abstract: A semiconductor device includes an N-well arranged in the principal surface of a P-type semiconductor substrate, an N.sup.+ well contact arranged in the principal surface of the N-well, and an N.sup.+ buried region arranged to the bottom of the N-well.

Abstract: Described are method and apparatus for protecting content of a semiconductor non-volatile memory and a semiconductor non-volatile memory itself, the semiconductor non-volatile memory being constituted by, for example, a flash memory, so that a reduction in a life time of the non-volatile memory due to an excess number of times a refresh (rewrite) operation can be prevented. For example, a first data deterioration determining voltage V.sub.1 is applied via a row decoder to one of word lines to which a selected bit is connected to determine whether the selected bit is turned on and a second data deterioration determining voltage V.sub.2 is applied to the same word line to determine whether the selected bit is turned off. The results of the determinations are stored in a second memory unit.

Abstract: In a fuel injection system for an internal combustion engine, a control lever shaft interlocked with a governor spring is supported by a pump housing of a fuel injection pump with one and the other ends respectively located interiorly and exteriorly of the pump housing. A control lever for controlling the fuel injection amount is fixedly mounted on the other end of the control lever shaft. A cancel lever connected to an accelerator pedal through an accelerator rod is freely fitted on the other end of the control lever shaft. The control lever and the cancel lever are disposed to abut against each other on a leading side of the cancel lever with reference to the angular movement thereof in a fuel decreasing direction. A cancel spring is connected between the control lever and the cancel lever to allow them to be angularly moved together. A dash pot for restricting the speed of movement of the control lever in a fuel increasing direction is arranged exteriorly of the pump housing.