Abstract: The present invention relates to a polishing composition for silicon wafer comprising silica; a basic compound; at least one compound selected from the group consisting of amino acid derivatives represented by formula (1) wherein R1, R2 and R3 are identical or different one another, C1-12alkylene group that may be substituted by hydroxyl group, carboxyl group, phenyl group or amino group, and formula (2) wherein R4 and R5 are identical or different each other, hydrogen atom, or C1-12alkyl group that may be substituted by hydroxyl group, carboxyl group, phenyl group or amino group, with a proviso that both R4 and R5 are not hydrogen at the same time, and R6 is C1-12alkylene group that may be substituted by hydroxyl group, carboxyl group, phenyl group or amino group, and the salts of the amino acid derivatives; and water. The polishing composition can prevent metal contamination, particularly copper contamination in polishing of silicon wafer.

Abstract: A three-phase voltage-fed AC/DC converter includes a conversion circuit which converts power from a DC voltage source to three-phase AC power. The converter further includes a UM conversion circuit which carries out dq conversion of the three-phase output voltage, a superior voltage control circuit which outputs a voltage reference vector based on a superior reference vector and an output voltage vector obtained by the UM conversion circuit, an inferior voltage control circuit which outputs a PWM reference based on the voltage reference vector and the output voltage vector, and a frequency control circuit which synchronizes a value generated based on a q-axis component from the UM conversion circuit with a rotation angle of a conversion matrix in the UM conversion circuit.

Abstract: To suppress a DC component in AC power in a power converter for converting DC power to AC power. DC power is converted to AC power by a converter 2, and the AC power is supplied to output terminals u1 and u2 via an inductor 3. The converter 2 is controlled based on an error ?(t) between an output current ip(t) outputted from the converter 2 and a target current j(t) outputted from a target current generation means 110 as a target value for the output current ip(t), and a DC component VD in an output terminal voltage v(t) is detected by a voltage detection means 18. A DC component ID is suppressed by correcting a target current j(t) by a DC component suppression means 8.

Abstract: To suppress a DC component in AC power in a power converter for converting DC power to AC power. DC power is converted to AC power by a converter 2, and the AC power is supplied to output terminals u1 and u2 via an inductor 3. The converter 2 is controlled based on an error ?(t) between an output current iP(t) outputted from the converter 2 and a target current j(t) outputted from a target current generation means 110 as a target value for the output current iP(t), and a DC component VD in an output terminal voltage v (t) is detected by a voltage detection means 18. A DC component ID is suppressed by correcting a target current j(t) by a DC component suppression means 8.

Abstract: The objective of the present invention is to provide a power source and operational method in which a plurality of inverters are connected in parallel with the ability to suppress the crosscurrent with a very simple means. The present invention is an electric power source in which a plurality of inverted operate on the same frequency and the plurality of inverters are connected in parallel so that a resistance value expressed by (1??·G)/(?·G) here ? is the output voltage feedback gain, ? is the output current feed forward gain, and G is the inverter current gain, is made to be the equivalent output impedance; and is an electrical power source in which the cross-current between the inverters are made to be an acceptable value or below by adjusting the output of each of the inverters by controlling the equivalent output impedance by modifying both or either one of the output voltage feedback gain ? or the output current feed forward gain ?.

Abstract: A sodium sulfur cell comprising an anode active material of metallic sodium, and a cathode active material of sulfur or sodium polysulfide, and a beta alumina solid electrolyte separator, the above active materials containing, as an impurity, calcium of at most 20 ppm and/or potassium of at most 200 ppm, by weight. The cell of the invention has excellent characteristics, particularly prolonged electromotive life.

Abstract: A solid electrolyte tube for sodium sulfur cells, having an outer surface of a roughness defined by an arithmetical mean deviation of the profile (R.sub.a) of not exceeding 2.0 .mu.m and a maximum height of the profile (R.sub.max) of not exceeding 15 .mu.m, is produced by leveling the outer surface of the solid electrolyte tube in a state of green body, bisque fired and calcined body, or fired body, by means of a finishing apparatus such as a centerless grinding machine, external cylindrical grinding machine, lathe, or the like. The solid electrolyte tube having a smooth and even surface can be prevented from crack formation due to local concentration of Na ion, S, sodium polysulfide and thermal stress thereon, so that it can improve durability and reliability.

Abstract: A semiconductor laser comprising in the direction parallel to a junction on both sides of a stripe-shaped active layer of double-hetero structure a semi-insulating current blocking layer which has a refractive index smaller than that of the active layer and of which the resistance is increased by doping of an impurity.

Abstract: A semiconductive laser comprises an active layer made in the shape of a crescent moon with the distribution of refractive index approximated by a quadratic curve. InGaAsP layers with a refractive index smaller than that of the active layer are disposed on both sides of the active layer.

Abstract: A method of operating a vehicle height adjusting apparatus including a vehicle body having front and rear wheels, contractible and extensible dampers disposed between the front and rear wheels and the vehicle body, a motor, a pump unit having inlet and outlet ports and drivable by the motor for supplying a working fluid under pressure to the dampers, a first valve member disposed in a first fluid passage between the pump unit and the dampers for adjusting the height of the vehicle, and a second valve member disposed in a second fluid passage between the inlet and outlet ports of the pump unit and connected to the first fluid passage for discharging the fluid from the dampers to the outlet port of the pump unit. The method comprises the steps of actuating the pump unit, opening the second valve member no later than simultaneously with the actuation of the pump unit, and closing the second valve member a predetermined period of time after it has been opened, whereby the height of the vehicle can be increased.