We present the fabrication and testing of a silicon carbide （SiC） balanced mass doublended tuning fork that survives harsh environments without compromising the device strain sensitivity and resolution bandwidth. Th...We present the fabrication and testing of a silicon carbide （SiC） balanced mass doublended tuning fork that survives harsh environments without compromising the device strain sensitivity and resolution bandwidth. The device features a material stack that survives corrosive environments and enables high-temperature operation. To perform hightemperature testing, a specialized setup was constructed that allows the tuning fork to be characterized using traditional silicon electronics. The tuning fork has been operated at 600°C in the presence of dry steam for short durations. This tuning fork has also been tested to 64 000 G using a hard-launch, soft-catch shock implemented with a light gas gun. However, the device still has a strain sensitivity of 66 Hz/μe and strain resolution of 0. 045 μe in a 10 kHz bandwidth. As such, this balanced-mass double-ended tuning fork can be used to create a variety of different sensors including strain gauges, accelerometers, gyroscopes, and pressure transducers. Given the adaptable fabrication process flow, this device could be useful to micro-electro-mechanical systems （MEMS） designers creating sensors for a variety of different applications.展开更多
为研究采煤机复杂工况下摇臂销轴的力学特性,采用等效销轴传感器和压力环传感器结合的测试方法,对采煤机不同截割工况时销轴载荷进行了在线测试,通过无线信号收发模块实现检测数据的存储,试验结束后将数据统一导出分析。试验表明:销轴...为研究采煤机复杂工况下摇臂销轴的力学特性,采用等效销轴传感器和压力环传感器结合的测试方法,对采煤机不同截割工况时销轴载荷进行了在线测试,通过无线信号收发模块实现检测数据的存储,试验结束后将数据统一导出分析。试验表明:销轴所受载荷与其位置和工况有关,斜切状态下,X轴与Y轴方向上,采煤侧上销轴载荷最大,波动最剧烈;Z轴方向上,采空侧下销轴载荷最大。采煤机斜切进刀过程中,径向载荷和轴向载荷极值均出现在煤壁侧下销轴,其载荷值分别为83 617.2 k N和300.9 k N,在销轴承受极值载荷时,其剪切应力和屈服应力均在极限强度内,证明销轴设计安全可靠,为摇臂销轴设计提供了重要依据。展开更多
In this paper, we study an area localization problem in large scale underwater wireless sensor networks （UWSNs）. The limited bandwidth, the severely impaired channel and the cost of underwater equipment all make the...In this paper, we study an area localization problem in large scale underwater wireless sensor networks （UWSNs）. The limited bandwidth, the severely impaired channel and the cost of underwater equipment all make the underwater localization problem very challenging. Exact localization is very difficult for UWSNs in deep underwater environment. We propose a range free method based on mobile detachable elevator transceiver （DET） and 3D multi-power area localization scheme （3D-MALS） to address the challenging problem. In the proposed scheme, the ideas of 2D multi-power area localization scheme （2D-ALS） and utilizing DET are used to achieve the simplicity, location accuracy, scalability and low cost performances. The DET can rise and get down to broadcast its position. And it is assumed that all the underwater nodes underwater have pressure sensors and know their z coordinates. We evaluate the performances of 2D-ALS and our proposed 3D-MALS schemes under both ideal and non-ideal channel propagation conditions, in terms of localization error and localization ratio. The simulation results show that our proposed scheme is much more efficient than the 2D-ALS.展开更多
We propose a novel pressure sensor based on the combination of the ring resonator with two straight waveguides and a two-end fixed beam.The principle of this device is acquiring the system static pressure by monitorin...We propose a novel pressure sensor based on the combination of the ring resonator with two straight waveguides and a two-end fixed beam.The principle of this device is acquiring the system static pressure by monitoring the changes in the transmission wavelength shift of the ring resonator with double waveguides.The numerical results show that the sensitivity of the system is up to 49.3 pm/kPa while the pressure range is 0—300 kPa.The thickness of the fixed beam is an important factor which impacts the sensitivity of the system.This device can provide support for fabricating high sensitivity and low cost micro pressure sensors.展开更多
文摘We present the fabrication and testing of a silicon carbide （SiC） balanced mass doublended tuning fork that survives harsh environments without compromising the device strain sensitivity and resolution bandwidth. The device features a material stack that survives corrosive environments and enables high-temperature operation. To perform hightemperature testing, a specialized setup was constructed that allows the tuning fork to be characterized using traditional silicon electronics. The tuning fork has been operated at 600°C in the presence of dry steam for short durations. This tuning fork has also been tested to 64 000 G using a hard-launch, soft-catch shock implemented with a light gas gun. However, the device still has a strain sensitivity of 66 Hz/μe and strain resolution of 0. 045 μe in a 10 kHz bandwidth. As such, this balanced-mass double-ended tuning fork can be used to create a variety of different sensors including strain gauges, accelerometers, gyroscopes, and pressure transducers. Given the adaptable fabrication process flow, this device could be useful to micro-electro-mechanical systems （MEMS） designers creating sensors for a variety of different applications.
文摘为研究采煤机复杂工况下摇臂销轴的力学特性,采用等效销轴传感器和压力环传感器结合的测试方法,对采煤机不同截割工况时销轴载荷进行了在线测试,通过无线信号收发模块实现检测数据的存储,试验结束后将数据统一导出分析。试验表明:销轴所受载荷与其位置和工况有关,斜切状态下,X轴与Y轴方向上,采煤侧上销轴载荷最大,波动最剧烈;Z轴方向上,采空侧下销轴载荷最大。采煤机斜切进刀过程中,径向载荷和轴向载荷极值均出现在煤壁侧下销轴,其载荷值分别为83 617.2 k N和300.9 k N,在销轴承受极值载荷时,其剪切应力和屈服应力均在极限强度内,证明销轴设计安全可靠,为摇臂销轴设计提供了重要依据。
基金the National Basic Research Program (973) of China (Nos.2006CB303007 and 2007CB316506)
文摘In this paper, we study an area localization problem in large scale underwater wireless sensor networks （UWSNs）. The limited bandwidth, the severely impaired channel and the cost of underwater equipment all make the underwater localization problem very challenging. Exact localization is very difficult for UWSNs in deep underwater environment. We propose a range free method based on mobile detachable elevator transceiver （DET） and 3D multi-power area localization scheme （3D-MALS） to address the challenging problem. In the proposed scheme, the ideas of 2D multi-power area localization scheme （2D-ALS） and utilizing DET are used to achieve the simplicity, location accuracy, scalability and low cost performances. The DET can rise and get down to broadcast its position. And it is assumed that all the underwater nodes underwater have pressure sensors and know their z coordinates. We evaluate the performances of 2D-ALS and our proposed 3D-MALS schemes under both ideal and non-ideal channel propagation conditions, in terms of localization error and localization ratio. The simulation results show that our proposed scheme is much more efficient than the 2D-ALS.
基金supported by the National Natural Science Foundation of China(No.6172044)the Natural Science Foundation of Hebei Province(No.F2012203204)
文摘We propose a novel pressure sensor based on the combination of the ring resonator with two straight waveguides and a two-end fixed beam.The principle of this device is acquiring the system static pressure by monitoring the changes in the transmission wavelength shift of the ring resonator with double waveguides.The numerical results show that the sensitivity of the system is up to 49.3 pm/kPa while the pressure range is 0—300 kPa.The thickness of the fixed beam is an important factor which impacts the sensitivity of the system.This device can provide support for fabricating high sensitivity and low cost micro pressure sensors.
