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管道泄漏信号和干扰信号的数字化判别方法 被引量:18
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作者 林伟国 王晓东 +1 位作者 戚元华 吴海燕 《石油学报》 EI CAS CSCD 北大核心 2014年第6期1197-1203,共7页
为了降低管道泄漏检测过程中调压、调泵和阀门动作等干扰信号引起的泄漏诊断误报率,在理论分析干扰信号互相关判别法存在问题的基础上,提出基于短间距安装双传感器结构的泄漏信号和干扰信号的数字化判别算法。把干扰信号和泄漏信号都归... 为了降低管道泄漏检测过程中调压、调泵和阀门动作等干扰信号引起的泄漏诊断误报率,在理论分析干扰信号互相关判别法存在问题的基础上,提出基于短间距安装双传感器结构的泄漏信号和干扰信号的数字化判别算法。把干扰信号和泄漏信号都归为异常信号,通过小波去噪、异常信号识别及异常信号提取等处理,提取出两路传感器输出信号中的异常信号跳变沿并计算两路信号的累积差分,根据累积差分的符号判断出双传感器信号的时移方向,进而判断出异常信号来源,实现干扰信号与泄漏信号的甄别。该方法大大降低了双传感器结构对安装间距的要求,克服了双传感器结构的硬件电路延时法对传感器灵敏度、响应特性和信号放大倍数的苛刻要求,在较低信号采样率的条件下实现了干扰信号的准确识别。实验室模拟异常信号的处理结果表明,对于液态介质(水),该方法可以实现干扰和泄漏信号的准确判别,双传感器安装间距可以缩小到1.5 m以内,采样频率可以降低到50 Hz。 展开更多
关键词 管道泄漏检测 双传感器结构 短间距安装 异常信号 数字化识别
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阀门内漏声波监测及其信号特征提取方法 被引量:17
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作者 林伟国 吴石恩 《振动与冲击》 EI CSCD 北大核心 2018年第9期120-126,共7页
针对管道阀门内漏故障,提出了一种采用双传感器结构的阀门内漏非介入式声波监测方法。设计了能够调节传感器和管壁的接触程度并锁紧,且可实现快速装卸的传感装置。分析比较了阀门正常与阀门内漏、管道敲击、阀门开启和关闭状态下启泵等... 针对管道阀门内漏故障,提出了一种采用双传感器结构的阀门内漏非介入式声波监测方法。设计了能够调节传感器和管壁的接触程度并锁紧,且可实现快速装卸的传感装置。分析比较了阀门正常与阀门内漏、管道敲击、阀门开启和关闭状态下启泵等干扰声波信号的时频域特征,提出了基于小波包能量分率的阀门内漏声波信号特征提取方法,有效区分了阀门内漏和外部干扰。该方法具有较高的泄漏检测灵敏度,可大大降低信号采样频率及阀门内漏诊断的难度。 展开更多
关键词 阀门内漏 双传感器结构 非介入式声波监测 快速装卸 小波包能量分率
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Moisture-triggered actuator and detector with high-performance: interface engineering of graphene oxide/ethyl cellulose
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作者 Bo Yang Wentuan Bi +4 位作者 Cheng'an Zhong Mingcan Huang Yong Ni Linghui He Changzheng Wu 《Science China Materials》 SCIE EI CSCD 2018年第10期1291-1296,共6页
Actuators that can directly convert other forms of environmental energy into mechanical work offer great application prospects in intriguing energy applications and smart devices. But to-date, low cohesion strength of... Actuators that can directly convert other forms of environmental energy into mechanical work offer great application prospects in intriguing energy applications and smart devices. But to-date, low cohesion strength of the interface and humidity responsive actuators primarily limit their applications. Herein, by experimentally optimizing interface of bimorph structure, we build graphene oxide/ethyl cellulose bidirectional bending actuators — a case of bimorphs with fast and reversible shape changes in response to environmental humidity gradients. Meanwhile, we employ the actuator as the engine to drive piezoelectric detector. In this case, graphene oxide and ethyl cellulose are combined with chemical bonds, successfully building a bimorph with binary synergy strengthening and toughening. The excellent hygroscopicity of graphene oxide accompanied with huge volume expansion triggers giant moisture responsiveness greater than 90 degrees. Moreover, the open circuit voltage of piezoelectric detector holds a peak value around 0.1 V and exhibits excellent reversibility. We anticipate that humidity-responsive actuator and detector hold promise for the application and expansion of smart devices in varieties of multifunctional nanosystems. 展开更多
关键词 ACTUATOR humidity responsiveness interface optimi-zation graphene oxide DETECTOR
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