Nanosized Carbon Black Combined with Ni₂O₃ as “Universal” Catalysts for Synergistically Catalyzing Carbonization of Polyolefin Wastes to Synthesize Carbon Nanotubes and Application for Supercapacitors

Wen, Xin,Chen, Xuecheng,Tian, Nana,Gong, Jiang,Liu, Jie,Rü,mmeli, Mark H.,Chu, Paul K.,Mijiwska, Ewa,Tang, Tao American Chemical Society 2014 Environmental science & technology Vol.48 No.7

<P>The catalytic carbonization of polyolefin materials to synthesize carbon nanotubes (CNTs) is a promising strategy for the processing and recycling of plastic wastes, but this approach is generally limited due to the selectivity of catalysts and the difficulties in separating the polyolefin mixture. In this study, the influence of nanosized carbon black (CB) and Ni<SUB>2</SUB>O<SUB>3</SUB> as a novel combined catalyst system on catalyzing carbonization of polypropylene (PP), polyethylene (PE), polystyrene (PS) and their blends was investigated. We showed that this combination was efficient to promote the carbonization of these polymers to produce CNTs with high yields and of good quality. Catalytic pyrolysis and model carbonization experiments indicated that the carbonization mechanism was attributed to the synergistic effect of the combined catalysts rendered by CB and Ni<SUB>2</SUB>O<SUB>3</SUB>: CB catalyzed the degradation of PP, PE, and PS to selectively produce more aromatic compounds, which were subsequently dehydrogenated and reassembled into CNTs via the catalytic action of CB together with Ni particles. Moreover, the performance of the synthesized CNTs as the electrode of supercapacitor was investigated. The supercapacitor displayed a high specific capacitance as compared to supercapacitors using commercial CNTs and CB. This difference was attributed to the relatively larger specific surface areas of our synthetic CNTs and their more oxygen-containing groups.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/esthag/2014/esthag.2014.48.issue-7/es404646e/production/images/medium/es-2013-04646e_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/es404646e'>ACS Electronic Supporting Info</A></P>

Fault Detection Based on a Combined Approach of FA-CP-ELM with Application to Wind Turbine System

Wenxin Yu,Shoudao Huang,Junnian Wang 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.1

In this paper, a novel wind turbine (WT) fault detection method, based on the Partial Least Squares (PLS), Firefly Algorithm (FA), Chaos Map (CP) and Extreme Learning Machine (ELM), which is proposed and explained in detail. The proposed method includes two procedures: a WT mathematical model with PLS and a prediction model with FA-CP-ELM. Since the WT system is modeled as a system using PLS, the ELM has been optimized by the FA and CP to improve the predictive performance. Then, it’s calculated the residual between the mathematical model and the predicted model. If a fault occurs, the residual will increase accordingly and exceed the tolerance range. Hence, a fault can be detected quickly. To demonstrate the feasibility and effectiveness of the proposed approach, the wind turbine system is tested with a fault point set in this system. According to the results of the example, this proposed method is found to achieve better performance.

New degradation feature extraction method of planetary gearbox based on alpha stable distribution

Wenxin Qiao,Xianglong Ni,Lei Wang,Xin Lv,Liwei Chen,Fucheng Sun 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.1

The planetary transmission system has been widely used in industry because of its various advantages. And the study on degradation feature extraction method of planetary gearbox is of major significance for mechanical system prognostics and health management (PHM). In this paper, the alpha stable distribution characteristics of planetary gearbox vibration signals in performance degradation process are verified. By observing the change of alpha stable distribution for planetary gearbox degradation experiment data, a new degradation feature extraction method based on alpha stable distribution is proposed, which is called the height of probability distribution (HPD). Through comparative analysis, it is determined that HPD has better linearity and less fluctuation compared with conventional degradation features in planetary gearbox accelerated degradation stage. Moreover, in the accelerated degradation stage, the degradation trend prediction result based on HPD is closer to the actual data than conventional degradation features no matter using Wiener-based or LSSVM-based prediction method. These conclusions indicate that the newly proposed HPD works well and gives accurate estimates for condition monitoring and degradation trend prediction of planetary gearbox.

QTL Mapping for Major Agronomic Traits across Two Years in Soybean (Glycine max L. Merr.)

Wenxin Li,Da-Hao Zheng,반규정,Suk-Ha Lee 한국작물학회 2008 Journal of crop science and biotechnology Vol.11 No.3

The agronomic traits, such as days to flowering and maturity, plant height, 100-seed weight and seed filling period, are quantitativelyinherited and important characters in soybean (Glycine max L. Merr.). A total of 126 F5 recombinant inbred lines (RILs) developed fromthe cross of PI 171451×Hwaeomputkong were used to identify quantitative trait loci (QTLs) for days to flowering (FD), days to maturity(MD), plant height (PH), 100-seed weight (SW), number of branches (NB) and seed filling period (FP). A total of 136 simple sequencerepeat (SSR) markers segregated in a RIL population were distributed over 20 linkage groups (LGs), covering 1073.9 cM of the soybeangenome with the average distance between adjacent markers of 7.9 cM. Five independent QTLs were identified for FD, three for MD, twofor PH, three for SW, one for NB and one for FP. Of these, three QTLs were related to more than two traits of FD, MD, PH, NB and FPand mapped near the same positions on LGs H and O. Thus, these traits could be correlated with biologically controlled major QTLs inthis soybean RIL population.

WEIGHTED ENDPOINT INEQUALITIES FOR MULTILINEAR MARCINKIEWICZ INTEGRAL OPERATOR

Wenxin, Yu,Liu, Lanzhe Korean Mathematical Society 2008 대한수학회보 Vol.45 No.1

We prove a sharp inequality for some multilinear operator related to Marcinkiewicz integral operator. As application, we obtain the weighted norm inequality and L log L type estimate for the multilinear operator.

A High Precision Time-frequency Analysis Method

Wenxin Zhang,Xiaojun Liu,Xiuwei Chen,Qing Liu,Guangyou Fang 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.7

To analysis the signal whose frequency changes as time, this article presents a new time-frequency analysis method based on short-time fractional Fourier transform (FRFT) and integration of midpoints. This method uses window functions to divide the signal to many pieces, then the FRFT is used to calculate the frequency modulation (FM) rate of each piece. A chirp signal can be built based on the FM rate and the intermediate frequency (IF) signal is obtained by mixing the chirp signal and the primary signal. The frequency of the midpoints can be estimated by the chirp-z transform (CZT), therefore the frequency of every piece can be calculated. This method avoids the impact that the quick change of frequency leads to the error of short-time Fourier transform. It also can reduce the error brought by the estimation of chirp rate. Therefore, the method can improve the accuracy of time-frequency analysis. This article also puts forward a method to search the order of fractional Fourier transform, and the computer simulation and measurement verifies the effectiveness of the proposed algorithm.

Decentralized Neural Network-based Excitation Control of Large-scale Power Systems

Wenxin Liu,Jagannathan Sarangapani,Ganesh K. Venayagamoorthy,Li Liu,Donald C. Wunsch II,Mariesa L. Crow,David A. Cartes 대한전기학회 2007 International Journal of Control, Automation, and Vol.5 No.5

This paper presents a neural network based decentralized excitation controller design for large-scale power systems. The proposed controller design considers not only the dynamics of generators but also the algebraic constraints of the power flow equations. The control signals are calculated using only local signals. The transient stability and the coordination of the subsystem control activities are guaranteed through rigorous stability analysis. Neural networks in the controller design are used to approximate the unknown/imprecise dynamics of the local power system and the interconnections. All signals in the closed loop system are guaranteed to be uniformly ultimately bounded. To evaluate its performance, the proposed controller design is compared with conventional controllers optimized using particle swarm optimization. Simulations with a three-machine power system under different disturbances demonstrate the effectiveness of the proposed controller design.

Fault Diagnosis of a Nonlinear Dynamic System Based on Sliding Mode

Wenxin Yu,Junnian Wang,Dan Jiang 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.6

Actuator failures and the failures of controlled objects are often considered together. To overcome this limitation, a class of sliding mode observers for the fault diagnosis of nonlinear systems is designed in this paper. Due to the influence of the sliding mode function, the control strategy and the residual change of the observer exhibit certain trends governed by specific relations. Therefore, according to the changes in the control strategy and the observer residuals, the sensor and actuator faults in nonlinear systems can be determined. Finally, the effectiveness of the proposed method is verified based on simulations of a DC motor system.

Impact of Grafting Density on the Self-Assembly and Hydrophilicity of Succinylated Collagen

Wenxin Wang,Feiyi Shu,Lingyu Pan,Shanshan Huang,Xiao Tu,Ping Li,Siman Li,Yuanyuan Li,Chengzhi Xu,Yang Sun,Juntao Zhang,Haibo Wang 한국고분자학회 2020 Macromolecular Research Vol.28 No.6

Modification of protein could give their new functionality but would affect their intrinsic property and activity. In this paper, a series of succinylated collagen (SCol(n/1)) (n≥1) were prepared by modification of collagen with succinic anhydride at different molar ratio to amino groups amount of collagen. The impact of grafting density on the intrinsic self-assembly and additional hydrophilicity of succinylated collagen was explored. The results revealed that excessive grafting density of succinylated collagen would improve their hydrophilicity but weaken their self-assembly property, although the triple helix of collagen could be reserved after succinylation. SCol(1/1) (grafting density of 17%) with self-assembly property and good hydrophilicity was chosen to compare with native collagen. Compared to native collagen, thermostability of SCol(1/1) decreased slightly, however, SCol(1/1) could form softer hydrogel, which was more favorable for the proliferation of NIH/3 T3. The present work would help us to further understand the importance of grafting density for the design of modified collagen with intrinsic self-assembly property and additional new functionality.

Identification of QTLs Associated with Resistance to Riptortus clavatus Thunberg (Heteroptera: Alydidae) in Soybean (Glycine max L. Merr.)

Wenxin Li,반규정,Da-Hao Zheng,Weixian Liu,이영호,Sue Yeon Lee,이준호,Suk-Ha Lee 한국작물학회 2008 Journal of crop science and biotechnology Vol.11 No.4

The bean bug Riptortus clavatus Thunberg (Heteroptera: Alydidae) is an important pest, causing serious yield loss in soybean. Butthe information on mechanism of resistance to R. clavatus is limited. The objective of this study was to identify QTLs for R. clavatusresistance using simple sequence repeat (SSR) markers in a soybean population of recombinant inbred lines (RILs) developed fromthe cross PI 171451 × Hwaeomputkong. A genetic map from this population was constructed with a total of 136 SSR markers covering1073.9 cM on 20 linkage groups (LGs). With 126 F5 RILs, two independent QTLs for resistance to R. clavatus were mapped onLGs B1 and C2. The amount of phenotypic variation explained by these QTLs ranged from 12 to 16%. PI 171451 showed an escaperesponse to R. clavatus. Under feeding conditions, 14.4% of RILs showed greater resistance to R. clavatus than the resistant parent. The resistance to R. clavatus in soybean from PI 171451 was incomplete and quantitatively inherited and the QTLs for resistance toR. clavatus detected in the RIL population were not significantly affected by epistatic interactions.