In this paper, a novel differential reflective intensity optical fiber angular displacement sensor was proposed. This sensor can directly measure the angular and axial linear displacement of a flat surface. The structure of the sensor probe is simple and its basic principle was first analyzed according to the intensity modulation mechanisms. Secondly, in order to trim the dark output voltage to zero, the photoelectric conversion circuit was developed to adjust the signals. Then, the sensor model including the photoelectric conversion circuit has been established, and the influence of design parameters on the sensor output characteristic has been simulated. Finally, the design parameters of the sensor structure were obtained based on the simulation results; and an experimental test system was built for the sensor calibration. Experimental results show that the linear angular range and the sensitivity of the sensor were 74.4 and 0.051 V/°, respectively. Its change rules confirm the operating principle of the sensor well.

The Chinese government encourages villagers to withdraw from rural homesteads and puts these homesteads into the land market to revitalize rural homestead resources and make up for the lack of new construction land. Unfortunately, the implementation of the withdrawal from rural homesteads (WRH) policy remains slow. To realize the effective promotion of WRH policy, exploring the impact of policy cognition (PC) on villagers’ WRH intentions has become the key to solving the above problems. Thus, field survey data on 280 villagers in 13 administrative villages in the Yangling Demonstration district of Shaanxi province were collected through a face-to-face household survey. In addition, combined with the extended theory of planned behavior (TPB), this study used the structural equation model (SEM) to empirically analyze the influence of PC on the intentions of villagers’ WRH. Our empirical results indicated that benefit cognition and difficulty cognition were the focus of the villagers and had positive and negative effects on the intention of WRH, respectively. Government behavior also played a positive role in villagers’ WRH intentions. Villagers would consider compensation standards, pay closer attention to improving the living environment and employment opportunities, and express individual intentions. We believe policymakers should systematically consider the various impacts of WRH policy on villagers and build the villagers’ participation system of WRH and cross-regional transaction system for WRH indicators. This paper further enriches the conceptual framework of PC, which may help us better understand villagers’ responses to relevant policy reforms.

The benefits of reducing the tip clearance have been receiving many scholars’ attention all the time, which bring turbine efficiency increasing, emissions reduction, payloads increasing, and mission range abilities extension. In order to gain the blade tip clearance dynamically, a prototype optical fiber measurement system was built and tested based on the rotor test rig. The optical fiber tip clearance measurement system consists of the reflective intensity-modulated optical fiber bundle (sensor), main signal processing unit, high-speed data acquisition card, and a computer. The static performance and dynamic performance experiments were conducted to verify the performance of the system we designed. In addition, the results show that the accuracy of the system is 25 μm or better; the stability of the measurement system was evaluated in room temperature. The clearance measurement range is about 5 mm, and sensitivity of the sensor is 0.0733/mm. Furthermore, the typical tip clearance dynamic measurement experiment results show that the system has good dynamic response characteristics as well. The system will provide a new tool for engine health monitoring or fast active tip clearance control.

No abstract