Static ice pressure affects safe operation of hydraulic structures. However, current detection methods are hindered by the following limitations： poor real-time performance and errors owing to the partial pressure of...Static ice pressure affects safe operation of hydraulic structures. However, current detection methods are hindered by the following limitations： poor real-time performance and errors owing to the partial pressure of the surrounding wall on traditional electrical resistance strain bellow pressure sensors. We developed a fiber optic sensor with a special pressure bellow to monitor the static ice pressure on hydraulic structures and used the sensor to measure static pressure in laboratory ice growth and melting tests from -30℃ to 5℃. The sensor resolution is 0.02 kPa and its sensitivity is 2.74 × 10-4/kPa. The experiments suggest that the static ice pressure peaks twice during ice growth and melting. The first peak appears when the ice temperature drops to -15℃ owing to the liquid water to solid ice transition. The second peak appears at 0℃ owing to the thermal expansion of the ice during ice melting. The novel fiber optic sensor exhibits stable performance, high resolution, and high sensitivity and it can be used to monitor the static ice pressure during ice growth and melting.展开更多
提到形容词、副词比较级自然想到than。然而中学英语教材中形容词比较级结构中不用than的例子不胜枚举。现归纳如下: 一、在定冠词the+形容词比较级+of结构中不用than The older of the two noblemen took a light and led me into a ba...提到形容词、副词比较级自然想到than。然而中学英语教材中形容词比较级结构中不用than的例子不胜枚举。现归纳如下: 一、在定冠词the+形容词比较级+of结构中不用than The older of the two noblemen took a light and led me into a back room. 两个贵族中年纪大一些的那个端着一盏灯领我进了一间后屋。展开更多
基金supported by the National Natural Science Foundation of China(No.51279122)the Graduate Innovation Foundation of Taiyuan University of Technology(No.2013A019)
文摘Static ice pressure affects safe operation of hydraulic structures. However, current detection methods are hindered by the following limitations： poor real-time performance and errors owing to the partial pressure of the surrounding wall on traditional electrical resistance strain bellow pressure sensors. We developed a fiber optic sensor with a special pressure bellow to monitor the static ice pressure on hydraulic structures and used the sensor to measure static pressure in laboratory ice growth and melting tests from -30℃ to 5℃. The sensor resolution is 0.02 kPa and its sensitivity is 2.74 × 10-4/kPa. The experiments suggest that the static ice pressure peaks twice during ice growth and melting. The first peak appears when the ice temperature drops to -15℃ owing to the liquid water to solid ice transition. The second peak appears at 0℃ owing to the thermal expansion of the ice during ice melting. The novel fiber optic sensor exhibits stable performance, high resolution, and high sensitivity and it can be used to monitor the static ice pressure during ice growth and melting.
文摘提到形容词、副词比较级自然想到than。然而中学英语教材中形容词比较级结构中不用than的例子不胜枚举。现归纳如下: 一、在定冠词the+形容词比较级+of结构中不用than The older of the two noblemen took a light and led me into a back room. 两个贵族中年纪大一些的那个端着一盏灯领我进了一间后屋。
