Abstract: A variable valve mechanism for an engine includes: a rocker shaft; a first rocker arm rotatably supported by the rocker shaft, for transmitting displacement of a first cam to a valve; a second rocker arm rotatably supported by the rocker shaft, for transmitting a displacement of a second cam to the valve; and a switching mechanism for switching a transmitting state and a non-transmitting state. The first rocker arm has a pair of first arm portions and a recess portion in which an upper end of the valve is inserted at an end portion of each of the first arm portions. The second rocker arm has a second arm portion disposed between the first arm portions. The first rocker arm is restricted from movement in an axis direction of the rocker shaft when an inner sidewall of the recess portion is in contact with the upper end of the valve. The second rocker arm is restricted from movement in the axis direction when the second arm portion is in contact with the first rocker arm.

Abstract: A high-power amplifier changes matching conditions of an output matching circuit 5 connected between a final stage amplifying element 3 and an output terminal 8 in response to the output power of the amplifying element 3. Thus, the efficiency at low output power can be greatly improved without reducing the efficiency at the maximum output. Besides, since it is not necessary to load a DC-DC converter, an increase in size or cost can be prevented.

Abstract: A high frequency power amplifier includes: a multi-finger transistor including transistor cells electrically connected in parallel; an input side matching circuit connected to gate electrodes of the transistor cells; and resonant circuits, each resonant circuit being connected between a gate electrode of a respective one of the transistor cells and the input side matching circuit. The resonant circuits resonate at a second harmonic of the operational frequency of the transistor or at a frequency within a predetermined range centered at the second harmonic and act as a short circuit or exhibit low impedance as seen from the gate electrode.

Abstract: A high-power amplifier changes matching conditions of an output matching circuit 5 connected between a final stage amplifying element 3 and an output terminal 8 in response to the output power of the amplifying element 3. Thus, the efficiency at low output power can be greatly improved without reducing the efficiency at the maximum output. Besides, since it is not necessary to load a DC-DC converter, an increase in size or cost can be prevented.

Abstract: A high frequency power amplifier includes: a multi-finger transistor including transistor cells electrically connected in parallel; an input side matching circuit connected to gate electrodes of the transistor cells; and resonant circuits, each resonant circuit being connected between a gate electrode of a respective one of the transistor cells and the input side matching circuit. The resonant circuits resonate at a second harmonic of the operational frequency of the transistor or at a frequency within a predetermined range centered at the second harmonic and act as a short circuit or exhibit low impedance as seen from the gate electrode.

Abstract: A high frequency amplifier includes a constant voltage driven amplifier 1 using as its amplifying element a bipolar transistor 7 with its base biased by a constant voltage, and a constant current driven amplifier 2 using as its amplifying element a bipolar transistor 8 with its base biased by a constant current. The idle current of the constant current driven amplifier 2 is set at a low value. In accordance with the idle current, the idle current of the constant voltage driven amplifier 1 is adjusted, and the two amplifiers are combined in parallel.

Abstract: A high frequency amplifier includes a constant voltage driven amplifier 1 using as its amplifying element a bipolar transistor 7 with its base biased by a constant voltage, and a constant current driven amplifier 2 using as its amplifying element a bipolar transistor 8 with its base biased by a constant current. The idle current of the constant current driven amplifier 2 is set at a low value. In accordance with the idle current, the idle current of the constant voltage driven amplifier 1 is adjusted, and the two amplifiers are combined in parallel.

Abstract: A semiconductor chip for amplification is connected between input-side and output-side matching circuits, and each of matching circuits includes balanced circuits which receive signals different in phase by 180 degrees, divided from an input signal. The balanced circuits are connected at a virtual grounding point, which is used as a grounding point sensitive to RF characteristics in an IPD. Thus, a semiconductor device can be free from influence of variations of grounding wires and can be reduced in size, weight, and cost.

Abstract: A second strip conductor is located, in a lamination direction of a multilayer substrate, at a is different position from that of a first strip conductor. A first grounding conductor and a second grounding conductor are disposed sequentially in the lamination direction of the multilayer substrate and sandwich the first strip conductor and the second strip conductor. The first grounding conductor includes a first grounding conductor portion for a wiring prohibited area in which no wiring may be placed, and a second grounding conductor portion for an area other than the wiring prohibited area. The second grounding conductor portion is positioned, in the lamination direction of the multilayer substrate, at a location is different from that of the first grounding conductor portion.

Abstract: A high-frequency amplifier in a power amplifier module includes, on a substrate on which the amplifier is formed, first- and second-stage amplifiers for receiving and amplifying an input signal, a harmonic processing circuit for matching of harmonics included in an output signal from the second-stage amplifier, and a low-pass filter receiving an output from the harmonic processing circuit to selectively pass a signal to be supplied to a non-reciprocal circuit element using a predetermined frequency as a cutoff frequency.

Abstract: The invention provides an enzymatic unhairing agent for use in an unhairing step in tanning for producing leather comprising an alkaline protease as an active component; a treatment solution comprising a pH-adjusting agent and the enzymatic unhairing agent; a method for enzymatic unhairing treatment in tanning for producing leather comprising contacting the treatment solution with a raw hide or skin; and a leather thus produced. According to the invention, it is attained markedly reduction of the pollution load in the unhairing waste water and leather and recovered hairs both of good quality can be obtained.

Abstract: A low impedance high efficiency amplifier is connected to a low impedance isolator. The low impedance high efficiency amplifier includes a plurality of amplifiers and an output matching circuit having a harmonic processing circuit arranged between a fundamental wave regulator circuit/a final stage amplifier and the low impedance isolator.

Abstract: A semiconductor chip for amplification is connected between the input-side and output-side matching circuits, and each of the matching circuits includes balanced circuits which receive signals different in phase by 180 degrees divided from an input signal and the balanced circuits are connected at a virtual grounding point (VE) which is used as a grounding point sensitive to RF characteristics in an IPD, and thus, a semiconductor device can be free from influence of variations of grounding wires and can be reduced in size, weight and cost.

Abstract: A second strip conductor 7 is provided such that its position in the lamination direction of the multilayer substrate 5 is different from that of the first strip conductor 8. A first grounding conductor 2 and a second grounding conductor 6 are disposed sequentially in the lamination direction of the multilayer substrate 5 and sandwiching the first strip conductor 8 and the second strip conductor 7. The first grounding conductor 2 includes a first grounding conductor portion 3 provided for the wiring prohibited area 1, and a second grounding conductor portion 4 provided for an area other than the wiring prohibited area 1. The second grounding conductor portion 4 is provided such that its position in the lamination direction of the multilayer substrate 5 is different from that of the first grounding conductor portion 3.

Abstract: A resonance circuit of a transmission line and a capacitor is connected to the base circuit of a transistor. The transmission line is shorter than one-quarter wavelength to make the resonant frequency of the resonant circuit higher than the frequency of a second harmonic. As a result, the angle of the reflection coefficient of the second harmonic when an input matching circuit side is viewed from the input terminal of the transistor ranges from 170° to 270° on a polar chart, and phase difference between the fundamental wave of the base current and the second harmonic decreases.

Abstract: The invention provides a heat radiating sheet which is not restricted by the shape and arrangement of a part to be cooled and which can be easily manufactured. A flexible heat radiating film having the effect of radiating infrared rays is formed on the front surface of a flexible heat absorbing layer having heat conductivity, and an adhesive layer consisting of a heat conductive adhesive agent is formed on the rear surface of the absorbing layer, so that the heat radiating sheet is formed to have flexibility.

Abstract: A high frequency power amplifier that can improve efficiency of an operation of a transistor without limiting any input-side higher harmonic load of an impedance matching circuit to a short-circuit load, and can increase reflection of higher harmonics. By adjusting line lengths and line widths of signal lines, a 2nd harmonic can be adjusted to be an open load (a reflected phase angle of &Ggr;in: 0-90°, the quantity of reflection: 0.6-1.0), and a 3rd harmonic is adjusted to be a short-circuit load (the reflected phase angle of &Ggr;in: 110-270°, the quantity of reflection: 0.6-1.0). With this input-side higher harmonic load of the impedance matching circuit, efficiency of transistor operation can be improved. By disposing a higher harmonic processing circuit closer to a transistor, a high frequency power amplifier with a shortened line length between the higher harmonic processing circuit and the transistor, and increased quantity of reflection of higher harmonics is produced.

Abstract: A resonance circuit constituted by a transmission line and a capacitor is connected to the base circuit of a transistor. The line length of the transmission line is set to be shorter than ¼ wavelength to make the resonant frequency of the resonance circuit higher than frequency 2fo of a 2nd harmonic. As a result, an angle of a reflection coefficient &Ggr;s2fo of the 2nd harmonic when an input matching circuit side is viewed from the input terminal of the transistor ranges from 170° to 270° on a polar chart, and a phase difference between the fundamental wave of a base current and the 2nd harmonic decreases.

Abstract: A signal corresponding to a progressive wave's power is extracted from a progressive-wave coupler connected between an output of an amplifier and an antenna. A signal corresponding to reflected power is also extracted from a coupler for reflection. An arithmetic circuit calculates a voltage supplied to the amplifier and a control voltage is supplied to the amplifier, and furthermore a power supply voltage based on the result of the operation is supplied from a DC-DC converter to the amplifier.

Abstract: A radio-frequency composite element includes an element substrate carrying a high-efficiency amplifier, a transmission line, and an isolator. The amplifier is a semiconductor element mounted on a multilayer substrate and enveloped by a cover. The transmission line furnished on the element substrate connecting an output terminal of the high-efficiency amplifier with an input terminal of the isolator, so that the components make up an integral composite element.