The Design of All Fiber Laser Heterodyne Detection System

Cao Miao,Cui Wenjie,Yao Qinghua 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.5

The traditional method of heterodyne detection is improved in this paper based on the principle of laser heterodyne detection. The laser heterodyne detection system is designed with all-fiber laser radar in all fiber system, and the laser, the optical system, the receiving device and so on are connected via the passive component. The system can mix the local oscillation light with signal light of measured object information in the photodetector surface, and the difference frequency signal is obtained. Then the signal is filtered and amplified by the signal processing technique to eliminate the DC component, and the desired difference frequency signal is obtained. Through the analysis of the performance of all fiber laser heterodyne detection system, the system has a strong ability to detect weak signal, high conversion gain and signal to noise ratio, and has a good filtering effect. The system is very suitable for the application of laser ranging and so on.

Influence Analysis of Laser Spot Noise on the Measurement Accuracy of Laser Triangulation Method

Cao Miao,Wang Xiao,Yao Qinghua 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.6

Laser triangulation method, widely used in modern industry, is able to meet the requirements of fast, real-time and on-line detection within non-contact measurement method. Laser triangulation method is affected by many factors, and the laser spot noise is the main factor to affect application field of the laser triangulation method directly. Based on the laser triangulation principle, this paper deeply analyzes the effect of laser spot noise on the measurement accuracy of laser triangulation method, such as signal flicker noise, background noise, dark current noise, thermal noise, amplifier noise and so on, and puts forward a new method to use the filtering algorithm to overcome the laser spot noise for improving the accuracy of laser triangulation.

The Study of aDigital Equivalent Capacitor Circuit

QingHua Shang,Wenjie Cao,Zhen Huang,Xiaoqing Zhang 보안공학연구지원센터 2014 International Journal of Hybrid Information Techno Vol.7 No.3

The Study on the MRTD Measurement System of Medical Infrared Thermal Imager Based on Sub-Pixel Edge Detection Algorithm

Cao Miao,Cui Wenjie,Yao qinghua 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.7

MRTD (minimum resolvable temperature difference) is an important parameter to evaluate the infrared thermal imager. MRTD is not only related to the spatial resolution of the system, but also to many factors such as optical system, detector array and so on. The measurement technique and principle of the medical infrared thermal imager’s MRTD is deeply analyzed, and the MRTD measurement model is established in this paper. The MRTD measurement system of infrared thermal imager based on CCD imaging technology is designed. CCD is used to carry on the interpretation of temperature difference in this system instead of the human eye, which can avoid the effect of some factors on the subjective image quality evaluation, such as the contrast, the human interference flaw and so on. The sub-pixel edge detection algorithm is used to deal with the four-bar target image, which can effectively suppress the interface of the random noise on four-bar target image. The experimental results show that the MRTD testing accuracy of the system can reach 0.055℃.

Thermally Healable Polyurethanes Based on Furfural-Derived Monomers via Baylis-Hillman Reaction

Qinghua Huang,Fanghong Yang,Xingxing Cao,Zhongyu Hu,Chuanjie Cheng 한국고분자학회 2019 Macromolecular Research Vol.27 No.9

Two novel acrylate monomers with diol group, 2-hydroxyethyl 2-(furan- 2-yl(hydroxy)methyl)acrylate and methyl 2-(hydroxy(5-(hydroxymethyl)furan-2- yl)methyl)acrylate, were synthesized via Baylis-Hillman reaction in moderate yields. The monomer 2-hydroxyethyl 2-(furan-2-yl(hydroxy)methyl)acrylate was obtained from furfural and 2-hydroxyethyl acrylate (HEA); methyl 2-(hydroxy(5-(hydroxymethyl)furan- 2-yl)methyl)acrylate was prepared from 5-hydroxymethl furfural (HMF) and methyl acrylate. The monomer 2-hydroxyethyl 2-(furan-2-yl(hydroxy)methyl)acrylate reacted with toluene diisocyanate (TDI)-derived or hexamethylene diisocyanate (HDI)-derived diisocyanate oligomers to obtain the corresponding linear polyurethane oligmers PU-1T and PU-1H. Similarly, the diol methyl 2-(hydroxy(5-(hydroxymethyl)furan- 2-yl)methyl)acrylate reacted with TDI- or HDI-derived diisocyanate oligomers to obtain the corresponding linear polyurethane oligmers PU-2T and PU-2H. The numberaverage molecular weights of the linear polyurethane oligomers are approximately 300-350 Da. There are furan groups in the linear polyurethane oligomers PU-1T, PU-1H, PU-2T and PU-2H, which makes them capable of undergoing reversible Diels-Alder reaction with 4,4'- bismaleimidodiphenylmethane (BMI) to form the corresponding crosslinked polyurethanes CPU-1T, CPU-1H, CPU-2T and CPU-2H. Pencil hardness of CPU-1T, CPU-1H, CPU-2T and CPU-2H are 3H, 2H, 2H and HB, respectively. Glass transition temperatures of CPU-1T, CPU- 1H, CPU-2T and CPU-2H are 104.8, 97.6, 5.1 and 1.2 oC, respectively. TGA analysis shows that Td90 values of the CPUs range from 180 to 250 oC. Furthermore, the reversible crosslinked polyurethanes CPU-1T and CPU-1H can be completely self-healed at 90 oC for 3 h, while CPU-2T and CPU-2H can self-heal at 80 oC for 3 h presumably due to their low glass transition temperatures.

Research on the Dispersion Coefficient Measurement System based on CCD Imaging Automatic Alignment Technology

Cao Miao,Yao Qinghua 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.6

In order to measure the dispersion coefficient of glass and other transparent material rapidly and accurately, the paper studies the dispersion coefficient measurement system based on CCD imaging automatic alignment technology. On the basis of consideration of the air refractive index impacting on the measurement accuracy of dispersion coefficient, this paper rebuilds the mathematical model by the traditional dispersion coefficient measurement formula. Using the measuring angle technology of precision grating, the paper realizes the digital measurement of deflection angle of refracted ray. Sub-pixel edge detection algorithm is adopted to realize the automatic alignment of double line to single line, which has reduced artificial error of the dispersion coefficient in the measurement process. Finally, the paper combined the multichannel small collimator designed technology and the modern control technology to achieve the high precision measurement of refractive index. Demarcating the measurement system by known dispersion coefficient of optical glass, testing results and error of standard is less than ±2.3×10-6 absolutely.

Research on the Dispersion Coefficient Measurement System based on CCD Imaging Automatic Alignment Technology

Cao Miao,Yao Qinghua 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.7

In order to measure the dispersion coefficient of glass and other transparent material rapidly and accurately, the paper studies the dispersion coefficient measurement system based on CCD imaging automatic alignment technology. On the basis of consideration of the air refractive index impacting on the measurement accuracy of dispersion coefficient, this paper rebuilds the mathematical model by the traditional dispersion coefficient measurement formula. Using the measuring angle technology of precision grating, the paper realizes the digital measurement of deflection angle of refracted ray. Sub-pixel edge detection algorithm is adopted to realize the automatic alignment of double line to single line, which has reduced artificial error of the dispersion coefficient in the measurement process. Finally, the paper combined the multichannel small collimator designed technology and the modern control technology to achieve the high precision measurement of refractive index. Demarcating the measurement system by known dispersion coefficient of optical glass, testing results and error of standard is less than ±2.3×10-6 absolutely.

Receiver-driven Cooperation-based Concurrent Multipath Transfer over Heterogeneous Wireless Networks

( Yuanlong Cao ),( Qinghua Liu ),( Yi Zuo ),( Minghe Huang ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.7

The advantages of employing SCTP-based Concurrent Multipath Transfer (CMT) have been demonstrated to be very useful for data delivery over multi-homed wireless networks. However, there is still significant ongoing work addressing some remaining limitations and challenges. The most important concern when applying CMT to data delivery is related to handling packet reordering and buffer blocking. Another concern on this topic is that current sender-based CMT solutions seldom consider balancing the overhead and sharing the load between the sender and receiver. This paper proposes a novel Receiver-driven Cooperation-based Concurrent Multipath Transfer solution (CMT-Rev) with the following aims: (i) to balance overhead and share load between the sender and receiver, by moving some functions including congestion and flow control from the sender onto receiver; (ii) to mitigate the data reordering and buffer blocking problems, by using an adaptive receiver-cooperative path aggregation model, (iii) to adaptively transmit packets over multiple paths according to their receiver-inspired sending rate values, by employing a new receiver-aware data distribution scheduler. Simulation results show that CMT-Rev outperforms the existing CMT solutions in terms of data delivery performance.

Receiver-centric Buffer Blocking-aware Multipath Data Distribution in MPTCP-based Heterogeneous Wireless Networks

( Yuanlong Cao ),( Qinghua Liu ),( Yi Zuo ),( Fenfen Ke ),( Hao Wang ),( Minghe Huang ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.10

One major concern of applying Multipath TCP (MPTCP) to data delivery in heterogeneous wireless networks is that the utilization of asymmetric paths with diverse networking-related parameters may cause severe packet reordering and receive buffer blocking (RB²LOC). Although many efforts are devoting to addressing MPTCP`s packet reordering problems, their sender-controlled solutions do not consider balancing overhead between an MPTCP sender and receiver, and their fully MPTCP mode cannot make MPTCP achieve a desired performance. This paper proposes a novel receiver-centric buffer blocking-aware data scheduling strategy for MPTCP (dubbed MPTCP-rec) necessitating the following aims: (1) alleviating MPTCP`s packet reordering and RB²LOC problems, (2) improving the MPTCP performance, and (3) balancing load between the MPTCP sender and receiver. Simulation results show that the proposed MPTCP-rec solution outperforms the existing MPTCP solutions in terms of data delivery performance in heterogeneous wireless networks.

Analytical Solution of Magnetic Field in Permanent-Magnet Eddy-Current Couplings by Considering the Effects of Slots and Iron-Core Protrusions

Xin Dai,Qinghua Liang,Chao Ren,Jiayong Cao,Jinqiu Mo,Shigang Wang 한국자기학회 2015 Journal of Magnetics Vol.20 No.3

In this study, we propose an analytical model for studying magnetic fields in radial-flux permanent-magnet eddy-current couplings by considering the effects of slots and iron-core protrusions on the eddy currents. We focus on the analytical prediction of the air-gap field by considering the influence of eddy currents induced in conducting bars. In the proposed model, the permanent magnet region is treated as the source of a timevarying magnetic field and the moving-conductor eddy current problem is solved based on the resolution of time-harmonic Helmholtz equations. The spatial harmonics in the air gap and in slots, as well as the time harmonics are all considered in the analytical calculation. Based on the proposed field model, the electromagnetic torque is computed by using the Maxwell stress tensor method. Nonlinear finite element analysis is performed to validate the analytical model. The proposed model can be used for permanent-magnet eddy-current couplings with any slot?pole combination.