We report the optical response characteristics of A1/Ti bilayer transition edge sensors （TESs）, which are mainly comprised of A1/Ti bilayer thermometers and suspended SiN membranes for thermal isolation. The measure...We report the optical response characteristics of A1/Ti bilayer transition edge sensors （TESs）, which are mainly comprised of A1/Ti bilayer thermometers and suspended SiN membranes for thermal isolation. The measurement was performed in a 3He sorption refrigerator and the device＇s response to optical pulses was investigated using a pulsed laser source. Based on these measurements, we obtained the effective recovery time （τeff） of the devices at different biases and discussed the dependence of Veff on the bias. The device with a 940 μm × 940 μm continuous suspended SiN membrane demonstrated a fast response speed with τeff = 3.9 μs, which indicates a high temperature sensitivity （a = T/R·dR/dT = 326）. The results also showed that the TES exhibits good linearity under optical pulses of variable widths.展开更多
Hydrogen Peroxide vapour is becoming more popular to use as a method of decontamination, particularly for medical equipment and enclosures. It is highly effective in terms of microbiological kill rates and has a varie...Hydrogen Peroxide vapour is becoming more popular to use as a method of decontamination, particularly for medical equipment and enclosures. It is highly effective in terms of microbiological kill rates and has a variety of uses in healthcare. Although it is environmentally acceptable as it spontaneously decomposes into water and oxygen, concentration of hydrogen peroxide in the air needs to be monitored and controlled. A method of calibrating hydrogen peroxide vapor sensors is described which is based on the concentration of hydrogen peroxide in saturated vapour over a solution in water at a defined temperature. The saturated vapour is generated by bubbling dry air into a solution of hydrogen peroxide at a defined concentration and temperature. A vapour at a concentration of 0.7 ppm was produced and used to successfully calibrate a hydrogen peroxide sensor.展开更多
In this work a review of existing fire-detector types has been carried out along with the development of a low cost, portable, and reliable microcontroller based automated fire alarm system for remotely alerting any f...In this work a review of existing fire-detector types has been carried out along with the development of a low cost, portable, and reliable microcontroller based automated fire alarm system for remotely alerting any fire incidents in household or industrial premises. The aim of the system designed is to alert the distant property-owner efficiently and quickly by sending short message (SMS) via GSM network. A Linear integrated temperature sensor detects temperature beyond preset value whereas semiconductor type sensor detects presence of smoke or gas from fire hazards. The sensor units are connected via common data line to ATMega8L AVR microcontroller. A SIM300CZ GSM kit based network module, capable of operating in standard GSM bands, has been used to send alert messages. The system is implemented on printed circuit board (PCB) and tested under different experimental conditions to evaluate its performances.展开更多
基金supported by the National Basic Research Program of China(Grant No.2011CBA00304)Tsinghua University Initiative Scientific Research Program,China(Grant No.20131089314)the National Natural Science Foundation of China(Grant Nos.60836001 and 11273023)
文摘We report the optical response characteristics of A1/Ti bilayer transition edge sensors （TESs）, which are mainly comprised of A1/Ti bilayer thermometers and suspended SiN membranes for thermal isolation. The measurement was performed in a 3He sorption refrigerator and the device＇s response to optical pulses was investigated using a pulsed laser source. Based on these measurements, we obtained the effective recovery time （τeff） of the devices at different biases and discussed the dependence of Veff on the bias. The device with a 940 μm × 940 μm continuous suspended SiN membrane demonstrated a fast response speed with τeff = 3.9 μs, which indicates a high temperature sensitivity （a = T/R·dR/dT = 326）. The results also showed that the TES exhibits good linearity under optical pulses of variable widths.
文摘Hydrogen Peroxide vapour is becoming more popular to use as a method of decontamination, particularly for medical equipment and enclosures. It is highly effective in terms of microbiological kill rates and has a variety of uses in healthcare. Although it is environmentally acceptable as it spontaneously decomposes into water and oxygen, concentration of hydrogen peroxide in the air needs to be monitored and controlled. A method of calibrating hydrogen peroxide vapor sensors is described which is based on the concentration of hydrogen peroxide in saturated vapour over a solution in water at a defined temperature. The saturated vapour is generated by bubbling dry air into a solution of hydrogen peroxide at a defined concentration and temperature. A vapour at a concentration of 0.7 ppm was produced and used to successfully calibrate a hydrogen peroxide sensor.
文摘In this work a review of existing fire-detector types has been carried out along with the development of a low cost, portable, and reliable microcontroller based automated fire alarm system for remotely alerting any fire incidents in household or industrial premises. The aim of the system designed is to alert the distant property-owner efficiently and quickly by sending short message (SMS) via GSM network. A Linear integrated temperature sensor detects temperature beyond preset value whereas semiconductor type sensor detects presence of smoke or gas from fire hazards. The sensor units are connected via common data line to ATMega8L AVR microcontroller. A SIM300CZ GSM kit based network module, capable of operating in standard GSM bands, has been used to send alert messages. The system is implemented on printed circuit board (PCB) and tested under different experimental conditions to evaluate its performances.
