Research Progress in SiC-Based Ceramic Matrix Composites

Shaoming Dong,Zhen Wang,Haijun Zhou,Yan-Mei Kan,Xiangyu Zhang,Yusheng Ding,Le Gao,Bin Wu,Jianbao Hu 한국세라믹학회 2012 한국세라믹학회지 Vol.49 No.4

SiC-based ceramic matrix composites show many advantages over their monolithic ceramic counterparts, which makes them potential candidates for applications in various fields. Depending strongly on the chemical composition and microstructure of the fiber reinforcement, matrix as well as the fiber/matrix interphase in the material, the properties of ceramic matrix composites(CMCs) are highly tailorable. In this paper, the latest progresses in the interphase design, matrix modification and fiber reinforcement decoration of CMCs are reviewed, their effects on the properties of the CMCs are introduced.

Preparation of oxidation-protective SiC coatings for C/SiC composites by pulsed chemical vapor deposition

Shaoming Dong,Haiming Wen,Qing Zhou,Yusheng Ding 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.3

Single-layer SiC coatings and multilayer (C/SiC)n coatings for oxidation protection of C/SiC composites were prepared by a pulsed chemical vapor deposition (pulsed CVD) method, a modification of pulsed chemical vapor infiltration (pulsed CVI). Pulsed CVD enabled the original pores in the substrates to be filled by the coatings, which contributed to improved adhesion between the coatings and the substrates. No deposition defects were observed in the dense SiC coatings. Multilayer (C/SiC)n coatings could dissipate thermal stresses in the coatings, which reduced the number and width of micro-cracks in the coatings and accordingly improved the oxidation-protection capability of the coatings. Oxidation tests in dry air showed that the oxidation resistance of the coated composites was significantly improved compared with that of the uncoated ones. Single-layer SiC coatings and multilayer (C/SiC)n coatings for oxidation protection of C/SiC composites were prepared by a pulsed chemical vapor deposition (pulsed CVD) method, a modification of pulsed chemical vapor infiltration (pulsed CVI). Pulsed CVD enabled the original pores in the substrates to be filled by the coatings, which contributed to improved adhesion between the coatings and the substrates. No deposition defects were observed in the dense SiC coatings. Multilayer (C/SiC)n coatings could dissipate thermal stresses in the coatings, which reduced the number and width of micro-cracks in the coatings and accordingly improved the oxidation-protection capability of the coatings. Oxidation tests in dry air showed that the oxidation resistance of the coated composites was significantly improved compared with that of the uncoated ones.

Adaptive nonsingular sliding mode based guidance law with terminal angular constraint

Shaoming He,Defu Lin 한국항공우주학회 2014 International Journal of Aeronautical and Space Sc Vol.15 No.2

In this paper, a new adaptive nonsingular terminal sliding mode control theory based impact angle guidance law for intercepting maneuvering targets was documented. In the design procedure, a new adaptive law for target acceleration bound estimation was presented, which allowed the proposed guidance law to be used without the requirement of the information on the target maneuvering profiles. With the aid of Lyapunov stability criteria, the finite-time convergent characteristics of the line-of-sight angle and its derivative were proven in theory. Numerical simulations were also performed under various conditions to demonstrate the effectiveness of the proposed guidance law.

Adsorption of phenol and 1-naphthol onto XC-72 carbon

Shaoming Yu,Liming Zuo,Leilei Cheng,Erling Du 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.3

XC-72 carbon (XC-72) was characterized by SEM, XPS, N2 adsorption-desorption, particle size distribution analysis and potentiometric acid-base titration. The adsorption of phenol and 1-naphthol on XC-72 was studied as a function of contact time, pH, adsorbent content and temperature. The kinetic adsorption data were described well by the pseudo-second-order model. The adsorption isotherms of phenol were described well by Freundlich model, while the adsorption isotherms of 1-naphthol were fitted well by Langmuir model. The results demonstrated that XC-72 had much higher adsorption capacity for 1-naphthol than for phenol. The adsorption thermodynamic data were calculated from the temperature-dependent adsorption isotherms at T=293, 313 and 333 K, and the results indicated that the adsorption of phenol was an exothermic process, whereas the adsorption of 1-naphthol was an endothermic process. XC-72 is a suitable material for the preconcentration of phenol and 1-naphthol from large volumes of aqueous solutions.

Robust Output Feedback Tracking Control for a Class of Perturbed Systems Using NDOB and Nonlinear Continuous Predictive Control

Shaoming He,Defu Lin 제어·로봇·시스템학회 2016 International Journal of Control, Automation, and Vol.14 No.2

This paper presents a new robust output feedback tracking control scheme for a class of higher-orderuncertain systems. Since traditional nonlinear continuous predictive control requires accurate system model aswell as full system states to synthesize a controller, a composite control methodology is adopted in the proposedscheme. Specifically, the nonlinear disturbance observer (NDOB) is used to estimate the lumped uncertainty andthe unmeasured system states in an integrated manner while the nonlinear continuous predictive control regulatesthe system states to track the desired reference signal asymptotically. Detailed stability analysis is also presentedfor the closed-loop nonlinear observer-controller structure through two steps. Then, the obtained results are appliedto missile autopilot design to track the desired angle-of-attack signal. Finally, numerical simulations with somecomparisons are provided to demonstrate the effectiveness of the proposed formulation.

Research on Fast Face RecognitionAlgorithm Based on Block CS-LBP and HIK Kernel Method

Shaoming Pan,Gongkun Luo,Baozhong Ke,Kejiang Li 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.12

With the development of artificial intelligence and pattern recognition technology, more and more research related to human face is constantly developing in all walks of life. At the present stage, the traditional face recognition algorithm based on LBP and SVM is not good, and the process of feature extraction and feature classification are deeply studied in this paper. For feature extraction, the authors put forward an improved CS-LBP texture feature; for feature classification, the author uses the histogram intersection (HIK) kernel function to classify the features which has high efficiency and good effect. Subsequently, experiments are carried out on the Yale data set and the ORL data set. Experimental results show that the proposed algorithm has a significant improvement on the face recognition effect of face direction change, and the illumination change is slightly improved. In the natural environment, most face recognition has the influence of human face direction and noise, and the effect of noise is a hot direction of face recognition research in the future.

Adaptive nonsingular sliding mode based guidance law with terminal angular constraint

He, Shaoming,Lin, Defu The Korean Society for Aeronautical and Space Scie 2014 International Journal of Aeronautical and Space Sc Vol.15 No.2

In this paper, a new adaptive nonsingular terminal sliding mode control theory based impact angle guidance law for intercepting maneuvering targets was documented. In the design procedure, a new adaptive law for target acceleration bound estimation was presented, which allowed the proposed guidance law to be used without the requirement of the information on the target maneuvering profiles. With the aid of Lyapunov stability criteria, the finite-time convergent characteristics of the line-of-sight angle and its derivative were proven in theory. Numerical simulations were also performed under various conditions to demonstrate the effectiveness of the proposed guidance law.

Research on Vibration Saltation of the Transformer Core Caused by DC Bias of Based on Empirical Mode Decomposition

Zhen Shaoming,Liu Chenliang,Liu Xingmou 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.2

This paper presents a time–frequency analysis of the vibration of transformer under direct current (DC) bias through Hilbert– Huang transform (HHT). First, the empirical mode decomposition (EMD) process, which is the key in HHT, was introduced. The results of EMD, namely, intrinsic mode functions (IMFs), were calculated and summed by Hilbert transform (HT) to obtain time-dependent series in a 2D time–frequency domain. Next, the theory of DC bias for the transformer was analyzed. In consideration of the DC bias eff ect and in combination with the existing transformer vibration-related mechanism, the electromagnetic force equations of the transformer core were deduced. Lastly, a test system of vibration measurement for the transformer was set up. Three direction (x, y, and z axes) components of core vibration were measured. Decomposition of EMD and HHT spectra showed that vibration strength increased, and odd harmonics were produced with DC bias. This method illustrates the most obvious vibration distortion in the z-axis direction when the transformer is DC biased. Among them, the distortion of IMF3 has increased by more than 5 times. However, the distortion in the x-axis and y-axis directions also exists, but it is not obvious. Especially, 50 Hz component appeared in z-direction, 50 Hz component increased twofold in y-direction, and 150 Hz component increased threefold in z-direction. Results indicated that HHT can not only provide the occurrence time of DC bias but can also obtain the signal change components of the transformer vibration. Thus, HHT is a viable signal processing tool for transformer health monitoring.

Research Progress in SiC-Based Ceramic Matrix Composites

Dong, Shaoming,Wang, Zhen,Zhou, Haijun,Kan, Yan-Mei,Zhang, Xiangyu,Ding, Yusheng,Gao, Le,Wu, Bin,Hu, Jianbao The Korean Ceramic Society 2012 한국세라믹학회지 Vol.49 No.4

SiC-based ceramic matrix composites show many advantages over their monolithic ceramic counterparts, which makes them potential candidates for applications in various fields. Depending strongly on the chemical composition and microstructure of the fiber reinforcement, matrix as well as the fiber/matrix interphase in the material, the properties of ceramic matrix composites(CMCs) are highly tailorable. In this paper, the latest progresses in the interphase design, matrix modification and fiber reinforcement decoration of CMCs are reviewed, their effects on the properties of the CMCs are introduced.

Investigation on Physical Meaning of Three-loop Autopilot

이창훈,Shaoming He,Ju-Hyeon Hong 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.11

This paper aims to reveal the hidden physical meaning or the working principle of the three-loop autopilot. First, the minimal control structure that ensures the desired dynamic characteristics is analyzed. The results show that the three-loop autopilot has a redundant feedback loop from the minimal control structure standpoint. Based on this observation, its physical meaning is interpreted by utilizing the closed-loop tracking error dynamics in the presence of aerodynamic uncertainties. It turns out that the three-loop autopilot has the minimal control structure with an additional command which is based on the instantaneous direct model reference adaptive control. A clear mechanism of how the aerodynamic uncertainties are compensated is provided in the three-loop autopilot. Finally, numerical simulations are performed to validate our findings. The analysis results in this paper show the beauty of the three-loop autopilot: it can be considered as the most concise form to achieve desired dynamic characteristics and counteract model uncertainties. The potential importance of the results obtained is that they allow us toproperly design the three-loop autopilot by reflecting its physical meaning and have potential directions to improve the performance of the three-loop autopilot as well as the adaptive control.