摘要:
A quantitative echo sounder includes delay circuits, phase correction circuits, an incidence angle calculator and a directivity correction unit. The delay circuits adjust transmission start timing or phases of acoustic waves radiated by individual vibrating elements based on pitch and roll angles measured by a motion sensing device so that the direction of an acoustic axis of a transmitting beam matches a sounding direction. The phase correction circuits adjust phases of received echo signals based on the pitch and roll angles so that the direction of an acoustic axis of a receiving beam matches the sounding direction. The incidence angle calculator calculates echo signal incidence angle with respect to the sounding direction from phase differences among receiving beam signals obtained by four vibrating element groups. The directivity correction unit corrects a measured target strength by using the echo signal incidence angle calculated by the incidence angle calculator.
摘要:
A quantitative echo sounder includes delay circuits, phase correction circuits, an incidence angle calculator and a directivity correction unit. The delay circuits adjust transmission start timing or phases of acoustic waves radiated by individual vibrating elements based on pitch and roll angles measured by a motion sensing device so that the direction of an acoustic axis of a transmitting beam matches a sounding direction. The phase correction circuits adjust phases of received echo signals based on the pitch and roll angles so that the direction of an acoustic axis of a receiving beam matches the sounding direction. The incidence angle calculator calculates echo signal incidence angle with respect to the sounding direction from phase differences among receiving beam signals obtained by four vibrating element groups. The directivity correction unit corrects a measured target strength by using the echo signal incidence angle calculated by the incidence angle calculator.
摘要:
An exhaust gas control apparatus for an internal combustion engine includes a NOx adsorbent that is provided in an exhaust passage of an internal combustion engine, and that adsorbs nitrogen monoxide; an active oxygen supply device that supplies active oxygen to an area upstream of the NOx adsorbent; and a control portion that performs a first control that does not cause the active oxygen supply device to supply the active oxygen while exhaust gas flows to the NOx adsorbent at a time of cold start of the internal combustion engine, whereby the nitrogen monoxide is adsorbed by the NOx adsorbent, wherein the control portion performs a second control that causes the active oxygen supply device to supply the active oxygen after the first control is finished, whereby the nitrogen monoxide adsorbed by the NOx adsorbent is converted to a nitrate or a nitrate ion on the NOx adsorbent.