Pyrolysis kinetics and microstructure of thermal conversion products on toluene soluble component from two kinds of modified pitch

Yaming Zhu,Xuefei Zhao,Lijuan Gao,Junxia Cheng 한국탄소학회 2018 Carbon Letters Vol.28 No.-

Modified pitch A (MPA) and modified pitch B (MPB) were prepared by oxidative polymerization and thermal polycondensation reaction with refined pitch as the raw material, respectively. The toluene soluble components (TS-1 and TS-2) were obtained by solvent extraction from MPA and MPB, separately. The Flynn-Wall-Ozawa method and Kissinger-Akahira- Sunose method were used to calculate the pyrolysis activation energy of TS. The Satava- Sestak method was used to investigate the pyrolysis kinetic parameters of TS. Moreover, the optical microstructure of the thermal conversion products (TS-1-P and TS-2-P) by calcination shows that TS-1-P has more contents of mosaic structure and lower contents of fine fiber structure than TS-2-P. The research result obtained by a combination of X-ray diffraction and the curve-fitting method revealed that the ratios of ordered carbon crystallite (Ig) in TS-1-P and TS-2-P were 0.3793 and 0.4417, respectively. The distributions of carbon crystallite on TS-1-P and TS-2-P were calculated by Raman spectrum and curve-fitting analysis. They show that the thermal conversion product of TS-2 has a better graphite crystallite structure than TS-1.

Changes in structure of coal liquefied pitch during liquid‑phase carbonization process

Yaming Zhu,Xuefei Zhao,Ji Yuan,Chunlei Zhao,Chaoshuai Hu 한국탄소학회 2019 Carbon Letters Vol.29 No.1

residue as the raw material. As one of the preconceived raw material to produce high-quality coal-based carbon material, the changes of structure of CLP during liquid-phase carbonization process have been detailed investigated in this study. Actually, FTIR and curve-fitted method were used to quantitative analyze the aromaticity index (Iar), the ratio of CH3/ CH2, and basic functional groups (C=C, C=O, and C–O) of CLP and its liquid-phase carbonization products. Polarizing microscope, XRD and curve-fitted methods were used to characterize the microstructures of CLP and derived products. The results show that, branched chain and C=O group are the active reaction point in liquid-phase carbonization process. What’s more, 450 °C is a critical temperature point on the severe thermal polycondensation of CLP. The XRD and curve-fitted analysis of CLP and its liquid-phase carbonization products shows that, the stacking height (Lc), parallel layers (N), and the numbers of aromatic ring in each layer (n) are gradually larger with the improve of liquid-phase carbonization temperature.

Density functional theory study on Hg removal mechanisms of Cu-impregnated activated carbon prepared by simplified method

Yuqun Zhuo,Yaming Fan,Zhenwu Zhu,Liangliang Li,Qun Chen,Yu Lou 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.10

The preparation of activated carbon sorbent for Hg removal was simplified by combining activation and functionalization processes into one step. Jujube-based carbon material was first mixed with CuCl2 solution and then activated for the preparation of Cu-impregnated activated carbon. Physical and chemical properties of prepared activated carbon were investigated by means of N2 adsorption, SEM-EDS, XRD. A fixed-bed reactor with CEMS (Continuous emission monitoring system) was used to test the Hg adsorption ability of prepared activated carbon. DFT (Density functional theory) method of computational chemistry calculation was applied to identify the Hg adsorption mechanisms on sorbent surface.

Visual Tracking Using Improved Multiple Instance Learning with Co-training Framework for Moving Robot

( Zhiyu Zhou ),( Junjie Wang ),( Yaming Wang ),( Zefei Zhu ),( Jiayou Du ),( Xiangqi Liu ),( Jiaxin Quan ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.11

Object detection and tracking is the basic capability of mobile robots to achieve natural human-robot interaction. In this paper, an object tracking system of mobile robot is designed and validated using improved multiple instance learning algorithm. The improved multiple instance learning algorithm which prevents model drift significantly. Secondly, in order to improve the capability of classifiers, an active sample selection strategy is proposed by optimizing a bag Fisher information function instead of the bag likelihood function, which dynamically chooses most discriminative samples for classifier training. Furthermore, we integrate the co-training criterion into algorithm to update the appearance model accurately and avoid error accumulation. Finally, we evaluate our system on challenging sequences and an indoor environment in a laboratory. And the experiment results demonstrate that the proposed methods can stably and robustly track moving object.

Random vector functional link network with L21 norm regularization for robot visual servo control with feature constraint

Zhiyu Zhou,Jiusen Guo,Yaming Wang,Zefei Zhu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.9

Uncalibrated visual servoing control still encounters some challenges, such as calculating the interaction matrix with less cost and keeping the current image features within a camera’s field of view (FOV) in a noisy system environment. To solve these problems, we propose a new control method that uses a random vector functional link network with L21 norm regularization to calculate the interaction matrix and further estimate it with a robust information filter (RIF). L21 norm regularization can deal with the global sparsity of input weights and reduce the inherent complexity of a model. The RIF limits noise variance within a certain range to reduce the influence of uncertain noise on the servoing task. We also design a method that reacts to the control law in accordance with the coordinates of image features. It can adjust running speed in real time and keep image features within a camera’s FOV. We apply this method to a six-degrees-of-freedom eye-in-hand manipulator, and several simulations are performed. Simulation results show that the proposed algorithm performs well in the task and achieves good performance in terms of noise resistance. Image features barely escape from the camera’s FOV through the proposed constraint method.

Robot Manipulator Visual Servoing via Kalman Filter- Optimized Extreme Learning Machine and Fuzzy Logic

Zhiyu Zhou,Yanjun Hu,Jiangfei Ji,Yaming Wang,Zefei Zhu,Donghe Yang,Ji Chen 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.8

Visual servoing (VS) based on the Kalman filter (KF) algorithm, as in the case of KF-based image-based visual servoing (IBVS) systems, suffers from three problems in uncalibrated environments: the perturbation noises of the robot system, error of noise statistics, and slow convergence. To solve these three problems, we use an IBVS based on KF, African vultures optimization algorithm enhanced extreme learning machine (AVOA-ELM), and fuzzy logic (FL) in this paper. Firstly, KF online estimation of the Jacobian matrix. We propose an AVOA-ELM error compensation model to compensate for the sub-optimal estimation of the KF to solve the problems of disturbance noises and noise statistics error. Next, an FL controller is designed for gain adaptation. This approach addresses the problem of the slow convergence of the IBVS system with the KF. Then, we propose a visual servoing scheme combining FL and KF-AVOA-ELM (FL-KF-AVOA-ELM). Finally, we verify the algorithm on the 6-DOF robotic manipulator PUMA 560. Compared with the existing methods, our algorithm can solve the three problems mentioned above without camera parameters, robot kinematics model, and target depth information. We also compared the proposed method with other KF-based IBVS methods under different disturbance noise environments. And the proposed method achieves the best results under the three evaluation metrics.

Electrochemical performance of porous carbons derived from needle coke with different textures for supercapacitor electrode materials

Junxia Cheng,Zhenjie Lu,Xuefei Zhao,Xingxing Chen,Yaming Zhu,Hongyu Chu 한국탄소학회 2021 Carbon Letters Vol.31 No.1

The porous carbons with high specific surface area and excellent electrochemical properties were prepared using three types of green needle coke as raw materials. Electrochemical performances of the porous carbons derived from different microstructure green needle coke were investigated. The XRD and Raman spectra demonstrated that the content of the ordered carbon microcrystals were decreased and the content of amorphous and cross-linked structure were increased in the porous carbons with comparison to the raw materials. The results of N2 adsorption–desorption analysis verified that the content of ordered microcrystalline structure in the raw materials evidently influence the specific surface area and pore size distribution of the porous carbons. The porous carbon with 1665 m2 g?1 specific surface area and 2.89 nm average pore size has shown that the specific capacitance was 288 F g?1 at the current density 1 A g?1. Furthermore, the capacity retention was 94.93% and the Coulombic efficiency was 92.87% after 5000 charge/discharge cycles.