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Simulation and Investigation of Humidity Sensor based on Fiber Grating Fabry-Perot
Xiong Yanling,Liang Huan,Ren Naikui,Han Junsheng,Wu Mingze 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.6
In this article we have discussed the relative humidity sensor based on fiber grating Fabry-Perot (FBG-FP) coated with polyimide (PI) as a moisture sensitive film in theory. The moisture expansion coefficient of PI film as moisture strain on the FBG-FP sensor, which will result the change of the fiber core effective refractive index, the length of the F-P cavity and the period and effective refractive index of FBG. For that reason, the interference fringes of the reflection spectrum will be changed also. The shift of peak wavelength of the spectrum is traced by the simulation of Matlab. We discuss three situations: the coating on the FBG, FP cavity and the both, and regardless of the temperature changes, the simulation results show that the RH sensitivity can reach to 3.77pm/%RH, 2.12 pm/%RH, 4.05 pm/%RH, respectively.
Structural State Detection Using Transmissibility and Non-negative Matrix Factorization
Tongqun Ren,Meiling Hui,Junsheng Liang,Dazhi Wang,Liang He,Yonghang Chen 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.11
Transmissibility function (TF) was used in structural state detection which examined the change of the response-only vibration characteristics. The technology of signal correlation was utilized to obtain the TF between two testing points. Multiple TFs under different states were calculated as basic TFs and formed a state matrix. Subsequently, non-negative matrix factorization (NMF) was performed for the state matrix. Then both the basic and testing TFs were projected to the feature subspace derived from NMF so as to obtain the state feature index vectors, respectively. Finally, the Euclidean distance between state feature index vectors was defined as the state indicator. The experimental results indicated that this method can achieve better detection accuracy than that using magnitude indicator. Actually, a result with 100 percent correct detection was achieved when proper rule of dimensionality reduction was selected. This method is essentially a multivariate statistical process monitoring (MSPM) method. It is feasible in vibration-based structural state detection in the situation where the excitation signals are unavailable or inaccessible.
The Focused Electrode Ring for Electrohydrodynamic Jet and Printing on Insulated Substrate
Zeshan Abbas,Dazhi Wang,Liangkun Lu,Zhaoliang Du,Xiangyu Zhao,Kuipeng Zhao,Meng Si,Penghe Yin,Xi Zhang,Yan Cui,Junsheng Liang 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.5
Drop-on-demand electrohydrodynamic jet (DoD E-Jet) printing is considered a well-known type of fabrication method contemporary since it can be used to print high-resolution microstructures (< 1 μm) on various insulating substrates. This paper presents a numerical study of DoD E-Jet printing using a novel combination of needle and focused electrode ring to print stable and consistent microdroplets on a Polyethylene terephthalate substrate. Primarily, a phase field method was used to generate a stable cone-jet morphology that can allow the production of high-resolution micron/nano structures on PET substrates. The numerical simulation of cone-jet morphology was performed by COMSOL multiphysics software. Further, the impact of key parameters such as flow rate and dc positive pulse voltage was studied on cone-jet morphology through numerical simulation. Subsequently, optimized operating parameters i.e., f = 5.3 . 10 –15 m 3 s −1 , V n = 1.9 kV and V r = 0.7 kV were achieved by performing a series of numerical experiments. Then, optimized parameters by simulation were directly used to print arrays of stable droplets on PET substrate using the focused electrode ring in different locations by regulating distance 0.2 mm to 1.3 mm between needles to focused electrode ring. The minimum size of stable microdrop was measured 3 μm on PET substrate (thickness = 0.2 mm) using a 50 μm size quartz capillary maintaining a distance of 0.2 mm between combined needle and focused electrode ring. The experimental results proved that the simulation model is useful for printing different microstructures on insulating substrates and creating a promising production path for micro-electro mechanical system and nano-electro mechanical system (MEMS and NEMS).