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Gu Y.-F.,Northeastern University China | Zhao Y.,Northeastern University China | Lv R.-Q.,Northeastern University China | Yang Y.,Hebei Instruments and Meters Engineering Technology Research Center
Flow Measurement and Instrumentation | Year: 2016

The measurement lower limit of traditional turbine flowmeter is too large to satisfy the measurement requirements of small flow rate. A modified optical fiber turbine flowmeter based on the traditional turbine flowmeter principle was purposed. The front guide vane was specially designed with a helix angle to reduce the measurement lower limit and improve the measurement sensitivity. The theoretical model for the modified flowmeter was established based on planar vector triangle of flow velocities. From theoretical analysis, the conclusion that if the helix angle of front guide vane plus the helix angle of turbine equals to 90°, the starting volume flow rate of turbine can get minimum value and the sensitivity of the flowmeter can get maximum value was found. The correctness of the conclusion was verified by the Computational Fluid Dynamics (CFD) simulation. © 2016 Source

Hu S.,Northeastern University China | Zhao Y.,Northeastern University China | Yang Y.,Hebei Instruments and Meters Engineering Technology Research Center
Journal of Electrostatics | Year: 2015

A typical double photoconductive layer biochip focusing biological cells and forming specific pearl chains has been studied theoretically in this paper. It was composed of two photoconductive layers coated on the bottom and top of ITO-based glass. A light pattern was used to create face-to-face virtual electrodes and the resulting oscillatory spatial electric field was employed to induce the motion of polarizable neutral particles. In order to estimate the behaviors of the suspended particles, a numerical model including dielectrophoretic forces, dipole-dipole forces and other forces, was implemented by means of the Monte Carlo method. The results indicated that steady-state chains could be formed in a uniform electric field owing to the dipole moment effect. In a non-uniform electric field created by the use of a light pattern, the positive DEP force created a more focused pattern of chains. The work concerning the numerical simulation indicated that this chip could form fixed-length particle chains in perpendicular alignment to satisfy the structured assembly of tissues in the histological engineering application. © 2015 Elsevier B.V. Source

Wang P.,Northeastern University China | Zhao Y.,Northeastern University China | Yang Y.,Hebei Instruments and Meters Engineering Technology Research Center | Bi D.-J.,Northeastern University China
Sensors and Actuators, A: Physical | Year: 2015

Based on the structure of the traditional variable area flow meter and the principle of the optical fiber measurement, this article designed a new type of fiber Bragg grating (FBG) gas flow sensor. The tapered tube of the sensor is mounted vertically, and the float inside the tube moves up and down under the effect of the airflow. The longitudinal displacement of the float is converted to the deflection of the cantilever which bonded FBG under the action of magnetic force. Thus the flow variation could be transformed into the deflection of the cantilever, resulting in the change of FBG wavelength and phase. By detecting the change of the optical signal, the gas flow can be derived. The experimental results show that the sensor has the characteristics of good linearity and fast response time. The proposed sensor can determine the flow of air within 1-6.5 m3/h and the sensitivity of the sensor approximately reaches 0.22 nm/(m3/h). By optimizing the parameters of the sensor, the sensitivity and the accuracy can be improved accordingly. © 2014 Elsevier B.V. All rights reserved. Source

Zhao Y.,Northeastern University China | Li X.-G.,Northeastern University China | Cai L.,Northeastern University China | Yang Y.,Hebei Instruments and Meters Engineering Technology Research Center
Sensors and Actuators, B: Chemical | Year: 2015

A simple, ultra compact and highly sensitive photonic crystal fiber interferometer (PCFI) for external refractive index (ERI) sensing was proposed and demonstrated in this paper. The PCFI was formed by splicing photonic crystal fiber (PCF) between two single mode fibers (SMFs) with a slight core-offset. The both joints were up-tapered joints which acted as mode splitter/combiner and were made by fusion tapering technique. The Mach-Zehnder interferometer (MZI) incorporated intermodal interference between core mode and cladding modes of the PCF. When the ERI changed, a RI variation of cladding modes would occur and the output interference spectrum would shift. By measuring the wavelength shift of the interference pattern, temperature-insensitive RI measurement could be achieved. In addition, the refractive index sensing properties with the different PCF diameters were also investigated experimentally. Experimental results showed that RI sensitivity could be up to 252 nm/RIU in the refractive index range of 1.333-1.379. And it could be anticipated that RI sensitivity could be improved if the PCF diameter continues to decrease. Meanwhile, the sensor had the advantages of simple structure, small size, high sensitivity, low cost and low temperature sensitivity. © 2015 Elsevier B.V. All rights reserved. Source

Hu H.-F.,Northeastern University China | Zhao Y.,Northeastern University China | Zhang Y.-N.,Northeastern University China | Yang Y.,Hebei Instruments and Meters Engineering Technology Research Center
Instrumentation Science and Technology | Year: 2016

Infrared gas sensors employing hollow-core photonic crystal fibers are reported. A hollow-core photonic crystal fiber in the gas cell of the sensor was inserted between a single mode fiber and a multi-mode fiber in the light path. The gaps between the facets of hollow-core photonic crystal fiber and single mode fiber were optimized to increase the coupling efficiency. The gas chambers were modified to reduce the time for filling. Broadband and laser sources were employed to determine acetylene at concentrations between 0% and 0.6%. The resolution was 0.084 ppm and the stability was 0.556%. These sensors have promising applications for trace gas measurements. 2016 Copyright © Taylor & Francis Group, LLC Source

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