The qualitative and quantitative assessment of gas flow has become increasingly relevant in the use of everyday systems. The micro flow sensor, developed by Innovative Sensor Technology AG （Switzerland）, is by princ...The qualitative and quantitative assessment of gas flow has become increasingly relevant in the use of everyday systems. The micro flow sensor, developed by Innovative Sensor Technology AG （Switzerland）, is by principle a calorimetric flow sensor produced as a micro system on a glass substrate by means of photolithography and glass etching technology. These structures are arranged as a platinum micro heater and sensor in a Wheatstone bridge. The subsequent etching process produces an exposed area of polyimide membrane that is only a few microns thick and includes the resistive sensor structure as the active area. In addition, the RTD （resistance temperature detector） technology included on the sensor allows for the implementation of a variety of electronic biasing and signal processing modes. Since the sensor can be powered and the bridge can be measured in both CTA （constant temperature anemometer） and calorimetric mode, new possibilities are presented for both low and high flow rates with regard to temperature compensation, self-calibration and self-monitoring.展开更多
In this paper, the relationship between the protection and control of asynchronous motor and all sorts of protection devices for asynchronous motor are briefly expounded. The protection of motor has mainly developed i...In this paper, the relationship between the protection and control of asynchronous motor and all sorts of protection devices for asynchronous motor are briefly expounded. The protection of motor has mainly developed in three stages： thermal relay, electronic integrated protector, and microcomputer protector. In terms of sampling methods, the protection can be divided into two types： （1） the sampling current detection, which is implemented using a thermal relay with circuit breaker for the thermomagnetic tripping motor protection, and an electronic and solid state relay with circuit breaker and sof~ starter for the thermomagnetic tripping motor protection; （2） the sampling temperature detection, which is to directly detect electromotor winding temperature using bimetallic strip temperature relay, thermal protector, detecting coil, and heat resistance temperature relay. However, the second method is very expensive and difficult to maintain because a motor winding is necessary to directly bury, so it is used only in the cases requiring some frequent operations. Finally, the harmonious cooperation between overload protection device and motor or between overload protection device and short circuit protection device must be considered regardless of the protection device model.展开更多
Single-gallium antimonide （GaSb）-nanowire- based photodetectors were fabricated on both rigid SiO2/Si substrate and flexible polyethylene terephthalate （PET） substrates, both of which exhibited high responsivity, ...Single-gallium antimonide （GaSb）-nanowire- based photodetectors were fabricated on both rigid SiO2/Si substrate and flexible polyethylene terephthalate （PET） substrates, both of which exhibited high responsivity, fast- response, and long-term stability in photoswitching over a broad spectral range from ultraviolet to near infrared. Besides, the as-fabricated rigid device exhibited high responsivity of 7,350 A/W under illumination of 2 = 350 nm and light intensity P = 0.2 mW/cm^2, while the flexible device displays higher detectivity of 9.67 × 10^9 jones at 700 nm than the rigid one and lower noise equivalent power （NEP, NEP＊700 nm = 2.0 × 10^-12 W/Hz^1/2） for the much lower dark current on PET. The high responsivity, broad spectral detection from ultraviolet to near-infrared and long-term stability make GaSb nanowire one of the most important candidates to construct advanced optical sensors or other optoelectronic devices.展开更多
文摘The qualitative and quantitative assessment of gas flow has become increasingly relevant in the use of everyday systems. The micro flow sensor, developed by Innovative Sensor Technology AG （Switzerland）, is by principle a calorimetric flow sensor produced as a micro system on a glass substrate by means of photolithography and glass etching technology. These structures are arranged as a platinum micro heater and sensor in a Wheatstone bridge. The subsequent etching process produces an exposed area of polyimide membrane that is only a few microns thick and includes the resistive sensor structure as the active area. In addition, the RTD （resistance temperature detector） technology included on the sensor allows for the implementation of a variety of electronic biasing and signal processing modes. Since the sensor can be powered and the bridge can be measured in both CTA （constant temperature anemometer） and calorimetric mode, new possibilities are presented for both low and high flow rates with regard to temperature compensation, self-calibration and self-monitoring.
文摘In this paper, the relationship between the protection and control of asynchronous motor and all sorts of protection devices for asynchronous motor are briefly expounded. The protection of motor has mainly developed in three stages： thermal relay, electronic integrated protector, and microcomputer protector. In terms of sampling methods, the protection can be divided into two types： （1） the sampling current detection, which is implemented using a thermal relay with circuit breaker for the thermomagnetic tripping motor protection, and an electronic and solid state relay with circuit breaker and sof~ starter for the thermomagnetic tripping motor protection; （2） the sampling temperature detection, which is to directly detect electromotor winding temperature using bimetallic strip temperature relay, thermal protector, detecting coil, and heat resistance temperature relay. However, the second method is very expensive and difficult to maintain because a motor winding is necessary to directly bury, so it is used only in the cases requiring some frequent operations. Finally, the harmonious cooperation between overload protection device and motor or between overload protection device and short circuit protection device must be considered regardless of the protection device model.
基金supported by the National Natural Science Foundation of China(61377033,91123008)
文摘Single-gallium antimonide （GaSb）-nanowire- based photodetectors were fabricated on both rigid SiO2/Si substrate and flexible polyethylene terephthalate （PET） substrates, both of which exhibited high responsivity, fast- response, and long-term stability in photoswitching over a broad spectral range from ultraviolet to near infrared. Besides, the as-fabricated rigid device exhibited high responsivity of 7,350 A/W under illumination of 2 = 350 nm and light intensity P = 0.2 mW/cm^2, while the flexible device displays higher detectivity of 9.67 × 10^9 jones at 700 nm than the rigid one and lower noise equivalent power （NEP, NEP＊700 nm = 2.0 × 10^-12 W/Hz^1/2） for the much lower dark current on PET. The high responsivity, broad spectral detection from ultraviolet to near-infrared and long-term stability make GaSb nanowire one of the most important candidates to construct advanced optical sensors or other optoelectronic devices.
