摘要:
A semiconductor photo detector provided with a photo detecting portion, in which at least three semiconductor layers of the same conductivity type and different energy gaps are formed in the order of magnitude of the energy gap, and in which another semiconductor layer which has the same composition as a first semiconductor layer having the largest energy gap among the at least three semiconductor layers but is different in conductivity type from the first semiconductor layer is formed in contact with the first semiconductor layer at the optical input side of the semiconductor photo diode.
摘要:
An avalanche photodiode with a quantum well layer in which a thin film, periodic multilayer structure composed of two different semiconductors is formed in a carrier multiplying region, the effective ionization coefficient ratio of carriers is raised by a quantum well layer formed by the thin film, multilayer periodic structure, and only electrons of large ionization coefficient are injected into the multiplying region, thereby to reduce noise in the APD.
摘要:
A 1.3 .mu.m-band optical amplifier includes an optical amplifying fiber doped with Yb ion for emitting light in 1.02 .mu.m band by pumping of the 0.98 .mu.m band light and Pr ion for amplifying signal light by pumping of the 1.02 .mu.m band light. Both ends of the optical amplifying fiber are connected to optical fiber gratings for selectively reflecting 1.02 .mu.m band light via matching connecting members and tapered core optical fibers. The optical fiber gratings form a 1.02 .mu.m-band resonator. A Wavelength Division Multiplexing (WDM) optical coupler multiplexes the signal light and pumping light from an pumping laser and supplies the thus-multiplexed light to the optical fiber grating. The pumping laser comprises a laser device which causes laser oscillation at 0.98 .mu.m. A 1.5 .mu.m-band optical amplifier having a similar configuration is also disclosed.
摘要:
There is provided an air-fuel ratio control system for an internal combustion engine. The air-fuel ratio control system has an air-fuel ratio sensor arranged in an exhaust passage of the engine, which generates an output proportional to concentration of oxygen in exhaust gases emitted from the engine. The air-fuel ratio of a mixture supplied to the engine is controlled to a desired air-fuel ratio in response to the output from the air-fuel ratio sensor by the use of a proportional term and an integral term. A repetition period of inversion of the output from the air-fuel ratio sensor with respect to a predetermined reference value is calculated. Deterioration of the air-fuel ratio sensor is detected based the repetition period of inversion of the output from the air-fuel ratio sensor.
摘要:
A control apparatus for an internal-combustion engine includes a diagnosis device. The diagnosis device includes a determination section and an exhaust flow rate calculator configured to calculate an exhaust flow rate that reflects a volume flow amount of exhaust gas. A filter is configured to filter a signal representing an air-fuel ratio so that a 0.5th-order frequency component of engine speed is extracted from the signal. An integrator is configured to accumulate a filtered signal for a predetermined period of time to compute an integration value. A corrector is configured to correct the integration value to compute a corrected integration value each time the integration value is computed by the integrator. The determination section is configured to determine that cylinder-to-cylinder air-fuel ratio imbalance occurs in cylinders if the corrected integration value is greater than a predetermined threshold value after the predetermined period of time has elapsed.
摘要:
An optical beam diameter reducer for reducing a beam diameter of an optical beam comprises a three-layer structure composed of a central core, a refractive index inclined layer formed outside the core which refractive index gradually decreases toward the outside in the radial direction and a cladding layer formed outside the refractive index inclined layer.
摘要:
An oxygen concentration-detecting device detects the concentration of oxygen present in exhaust gases emitted from an internal combustion engine. The device includes an oxygen sensor of a limit current type. A heater heats the oxygen sensor. A first voltage is applied to the oxygen sensor and the concentration of oxygen is detected based on a first output current from the oxygen sensor obtained when the first voltage is applied to the oxygen sensor. A second voltage is applied to the oxygen sensor at a first repetition period and the internal resistance of the oxygen sensor is detected based on a second output current from the oxygen sensor obtained when the second voltage is applied to the oxygen sensor. The oxygen sensor is heated by the heater based on the internal resistance of the oxygen sensor detected. Values of the concentration of oxygen are sampled based on the first output current from the oxygen sensor at a second repetition period shorter than the first repetition period and the sampled values of the concentration of oxygen are stored. The concentration of oxygen is estimated based on the sampled values of the concentration of oxygen stored. In another form of the invention, a predetermined repetition period (first repetition period) at which the second voltage is applied is set in dependence on operating conditions of the engine.
摘要:
A semiconductor device with a distributed Bragg reflector is disclosed, in which periodic corrugations are formed between two semiconductor layers along the direction of travel of light. In accordance with the present invention, the periodic corrugations are formed by grid-like layers of a refractory material. The refractory material is an insulator, a refractory metal or a laminate member of an insulator and a refractory metal.
摘要:
In a cleaning device, the scraping up body and the rotating body rolling the adhesive roll are rotatably supported to the frame, and the adhesive roll is rotatably arranged on the scraping up body and the rotating body in parallel.