Abstract: A band pass filter circuit, wherein the band pass filter passes a frequency band between a first cutoff frequency and a second cutoff frequency with respect to an input frequency of an input signal, the band pass filter circuit includes: a first resonant circuit; a second resonant circuit; a third resonant circuit; at least one of a capacitive circuit and an inductive circuit. The first resonant circuit is connected to a signal line in series and sets a first resonant frequency as the first cutoff frequency. The second resonant circuit is connected to the signal line in series and sets a second resonant frequency as the second cutoff frequency. The third resonant circuit is connected to the signal line in parallel at a node where the first and second resonant circuits are connected, and sets a third resonant frequency as a band-pass center frequency between the first and second cutoff frequencies.

Abstract: A band pass filter circuit, wherein the band pass filter passes a frequency band between a first cutoff frequency and a second cutoff frequency with respect to an input frequency of an input signal, the band pass filter circuit includes: a first resonant circuit; a second resonant circuit; a third resonant circuit; at least one of a capacitive circuit and an inductive circuit. The first resonant circuit is connected to a signal line in series and sets a first resonant frequency as the first cutoff frequency. The second resonant circuit is connected to the signal line in series and sets a second resonant frequency as the second cutoff frequency. The third resonant circuit is connected to the signal line in parallel at a node where the first and second resonant circuits are connected, and sets a third resonant frequency as a band-pass center frequency between the first and second cutoff frequencies.

Abstract: A bias circuit which applies a bias voltage to a control terminal of a first active element for an RF signal amplification, includes a threshold voltage change compensation circuit and a first temperature compensation circuit. The threshold voltage change compensation circuit contains a second active element and compensates the bias voltage based on a change in threshold voltage of the first active element by using the second active element. The first temperature compensation circuit is connected between the control terminal and the voltage change compensation circuit and configured to compensate a change in the bias voltage based on a temperature change.

Abstract: A bias circuit which applies a bias voltage to a control terminal of a first active element for an RF signal amplification, includes a threshold voltage change compensation circuit and a first temperature compensation circuit. The threshold voltage change compensation circuit contains a second active element and compensates the bias voltage based on a change in threshold voltage of the first active element by using the second active element. The first temperature compensation circuit is connected between the control terminal and the voltage change compensation circuit and configured to compensate a change in the bias voltage based on a temperature change.

Abstract: A 4H-3,1-benzoxazin-4-one compound of the formula (I): ##STR1## wherein R is a hydrogen atom or alkyl radical, A is an amino acid residue or a peptide having 2 to 3 amino acid residues, which amino acid residue may have a side chain thereof protected by a protective radical, X is an alkyl, fluoroalkyl, OR.sup.1 or NHR.sup.1 radical wherein R.sup.1 is an alkyl radical, and Y is a protective radical for an amino radical, and salts thereof, exhibit an excellent inhibitory activity against serine proteases, especially against human leukocyte elastase, and thus are useful as an effective component of a medicine for inhibiting elastase.

Abstract: An artificial lung surfactant comprising (a) phosphatidyl choline and cardiolipin and/or phosphatidyl choline and cardiolipin and/or phosphatidyl glycerol in addition as phospholipids, wherein the content of the pospholipids is 80 to 95 wt % of the whole composition, (b) neutral lipids, wherein the content is 5 to 20 wt % of the whole composition, and (c) fatty acids, wherein the content is 0 to 10 wt % of the whole composition, and a remedy for respiratory distress syndrome containing the surfactant as an active principle.