An Improved Algorithm of Rough K-Means Clustering Based on Variable Weighted Distance Measure

Tengfei Zhang,Long Chen,Fumin Ma 보안공학연구지원센터 2014 International Journal of Database Theory and Appli Vol.7 No.6

Rough K-means algorithm has shown that it can provides a reasonable set of lower and upper bounds for a given dataset. With the conceptions of the lower and upper approximate sets, rough k-means clustering and its emerging derivatives become valid algorithms in vague information clustering. However, the most available algorithms ignore the difference of the distances between data objects and cluster centers when computing new mean for each cluster. To solve this issue, an improved algorithm of rough k-means clustering based on variable weighted distance measure is presented in this article. Comparative experimental results of real world data from UCI demonstrate the validity of the proposed algorithm.

Preparation of highly efficient self-healing anticorrosion epoxy coating by integration of benzotriazole corrosion inhibitor loaded 2D-COF

Tengfei Liu,Wen Li,Chenyang Zhang,Wei Wang,Wenwen Dou,Shougang Chen 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.97 No.-

In this work, multi-layer stacked two-dimensional (2D) covalent organic framework of TpPa-1 wassynthesized as nanocontainer to fabricate self-healing epoxy coating. The corrosion inhibitor ofbenzotriazole (BTA) was loaded into porous TpPa-1 (Tp: 1,3,5-Triformylphrogroglucinol, Pa-1: 1,4-phenylenediamine), and the load capacity was further improved by electrostatic adsorption. Then, 0.5 wt. % BTA/TpPa-1 and 0.5 wt.% TpPa-1 were added to the epoxy coating, respectively. The electrochemicalImpedance Spectroscopy (EIS) test shown that after 60 days of immersion, the impedance of the BTA/TpPa-1/EP in low-frequency region was 6.45108V cm2, while the impedance corresponding to theTpPa-1/EP coating was 9.04107V cm2. In addition, in the localized electrochemical impedancespectroscopy (LEIS) test, as the immersion time was extended, the impedance of TpPa-1/EP coating at thedefect continued to decrease, while the impedance at the defect of the BTA/TpPa-1/EP coating shown anupward trend, showing self-healing performance. This was due to the pH change when the metal at thedefect is corroded, which caused the BTA to be released from the nanocontainer and adhered to the metalsurface to form a protectivefilm. The improvement of the anti-corrosion performance of BTA/TpPa-1/EPcoating mainly comes from two aspects: (1) The good dispersion of TpPa-1 in EP coating improves thephysical shielding effect of the coating; (2) The controlled release of BTA can Realize the continuousformation of the bare metal surface protective layer.

Periosteum-inspired in situ CaP generated nanocomposite hydrogels with strong bone adhesion and superior stretchability for accelerated distraction osteogenesis

Lou Tengfei,Chen Kai,Luo Qiyu,Liu Changsheng,Yuan Yuan,Fan Cunyi 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Distraction osteogenesis (DO) is an efficacious but lengthy procedure to reconstruct segmental bone defects under the principle of tension-stress, during which the periosteum-mediated mechanical stimulation plays a pivotal role. Inspired by the dynamic process of DO and the mechanical stimulation of periosteum, a new design of bionic periosteum was developed to simulate the mechanical transduction of natural periosteum for the application in DO procedure.In this study, an injectable organic-inorganic hybrid hydrogel was developed based on a novel combination of the PEGylated poly (glycerol sebacate) (PEGS) polymer network and in situ formed CaP nanoparticles (ICPNs). Rat bone marrow mesenchymal stem cells (rBMSCs) and human umbilical vein endothelial cells (HUVECs) were cultured and tested in vitro to evaluate biocompatibility, cell adhesion, proliferation, and pro-osteogenic and pro-angiogenic activity. In vivo experiments were conducted in the rat tibial model of distraction osteogenesis.The developed nanocomposite hydrogels exhibited excellent injectability, robust bone adhesion, superior stretchability, and enhanced osteogenic activity. The results of in vitro and in vivo studies showed that PEGS/ICPN hydrogels could promote new bone formation and mineralization during the dynamic distraction process through the synergistic effects of angiogenesis and osteogenesis.This periosteum-inspired nanocomposite hydrogel represents a mechanobiology approach for effectively restoring large bone defects through the dynamic DO process.

Ultrasonic-Microwave Synergistic Synthesis of RGO–Bi2WO6 Photocatalyst with High Photoactivity for Basic Nitrogen Compounds in Light Oil

Ying Chen,Shenglun Ji,Tengfei Qiao,Shuang Miao,Yu Zhao 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.5

Graphene–Bi2WO6 composite photocatalyst with excellent photocatalytic properties were synthetized by ultrasonic-microwave synergistic method. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier infrared (FT-IR) spectrum, specific surface area analyzer (BET) and UV-Vis diffuse reflectance spectra. The photocatalytic activities of as-prepared samples were evaluated by degradation of pyridine in light oil under visible light irradiation. The results show that graphene changed appearance structure of Bi2WO6, which prevented the Bi2WO6 nanosheets reunion arrangement, and increased specific surface area of the catalyst. It can also reduce the recombination probability of photogenerated carrier, so as to improve the photocatalytic activity of the composite catalyst. The optimal amount of graphene is 2%, with the denitrification rate as high as 89.28%, much higher than that of pure Bi2WO6.

A Continuous Information Attribute Reduction Algorithm Based on Hierarchical Granulation

Long Chen,Tengfei Zhang 보안공학연구지원센터 2013 International Journal of Database Theory and Appli Vol.6 No.4

Mapping Risk Strategy of Social Stability Risk Considering Causal Relationships for Energy Infrastructure Projects

Ting Yuan,Tengfei Huo,Haie Huo,Xianjie Fang,Lilin Li,Miao Chen,Li Yu 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.11

Social stability risk posed by energy infrastructure projects can seriously affect urban sustainable development. There is thus a need to better understand how risk strategies are designed. However, there is few considerations on risk strategy design by breaking causal relationships. This research innovatively explores social stability risk variables by content mining, develops causal relationships of the social stability risk variables via Fault Tree Analysis (FTA) method, explores core risk variables and critical causal relationships by social network analysis (SNA) method, designs and validates risk strategies. The findings show that: 1) From the overall risk network perspective, the risk network contain 8 core risk variables. 2) From individual risk network perspective, there are 75 critical causal relationships. The top 3 critical causal relationships contain: projects that destroy the cultural landscape would be regarded as threating national security, which often inspires demonstrations among the local people and the line betweenness is the largest (35.589). Traffic congestion by the project is the main reason to cause local small-scale public petition, and the line betweenness is 35.075. Projects that threaten the ecological environment often bring psychological rejection of the project by the local public, and the line betweenness is 30.837. 3) Two scenarios are evaluated in terms of basic scenario and the experiment group scenario. Compared with the basic scenario, risk strategies considering causal relationships have significant effectiveness. The overall risk network density has reduced by 35.22%. The clustering coefficients has decreased by 16.20%. Intermediate central potential has reduced by 9.49%. This study offers a good reference for project managers to complete the sustainable risk control.

Weak fault detection method of rolling bearing based on testing signal far away from fault source

Zhiyuan He,Guo Chen,Tengfei Hao,Chunyu Teng,Minli Hou,Zhenjie Chen 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.3

In some cases, because of the complex internal structure of the machines, the positions of the vibration sensors are far away from the rolling bearings, such as in an aeroengine, causing the fault features to become extremely weak, which brings great challenge to the detection of rolling bearings. To address this problem, an integrated detection method is proposed. First, a method named MEDL is proposed to determine the optimal filter length in minimum entropy deconvolution (MED) to enhance the periodic fault impulse component in the weak signal, which accuracy is 1. After that, the MEDL is combined with variational mode decomposition (VMD) and autocorrelation to extract fault features from strong background noise. A series of fault simulation experiments for rolling bearings were conducted by using an aeroengine rotor experimental rig with casing. The results verify that the accuracy of the integrated detection method is 100 % in different measuring points, speeds and fault types. At the same time, it compared with spectral kurtosis (SK) and empirical wavelet transform (EWT). It proves that the integrated detection method is more robust in extracting the weak fault characteristic of rolling bearings from the casing signals effectively.

HOXA11-AS/miR-208-3p/ETS1 axis modulates osteogenic differentiation in bone marrow-derived mesenchymal stem cells

He Guisong,Long Tengfei,Chen Guofeng 대한독성 유전단백체 학회 2022 Molecular & cellular toxicology Vol.18 No.4

Background Osteoporosis (OP) is one of the most common bone diseases, resulting in increased mortality, persistent disability, and reduced quality of life. It is characterized by bone loss and low bone quality. Objective The objective of this study was to detect possible effects of HOXA11-AS on the progression of Osteoporosis (OP) and investigate the potential downstream targets. Results We found HOXA11-AS was low expression in BMSCs of OVX-induced rats. HOXA11-AS promoted osteoblastic differentiation and the expression of osteoblastic genes in BMSCs. Mechanically, we found HOXA11-AS negatively regulated the expression of miR-208a-3p, and miR-208a-3p could further target ETS proto-oncogene 1 (ETS1) in BMSCs. We further demonstrated HOXA11-AS promoted osteogenic differentiation of BMSCs through ETS1. Conclusion We therefore thought HOXA11-AS could serve as a promising target for the treatment of OP.

Rolling bearing fault convolutional neural network diagnosis method based on casing signal

Xiangyang Zhang,Guo Chen,Tengfei Hao,Zhiyuan He 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.6

Affected by the transmission path, it is very difficult to diagnose the vibration signal of the rolling bearing on the aircraft engine casing. A fault diagnosis method based on convolutional neural network is proposed for the weak vibration signal of the casing under the excitation of rolling bearing fault. Firstly, the processing method of vibration signal is studied. Through comparison and analysis, it is found that the fault characteristics of rolling bearing are more easily expressed by continuous wavelet scale spectrum, and a better recognition rate is obtained. Finally, the experiment was carried out with an aero-engine rotor tester with a casing, and the method based on wavelet scale spectrum and convolutional neural network was used for diagnosis. The results were compared with the support vector machine method. The results show that the method has a high recognition rate for the weak fault signals of different fault types collected on the aero engine case, and its fault recognition rate reaches 95.82 %, which verifies the superiority and potential of the method for rolling bearing fault diagnosis.

Behavior of grouped stud shear connectors between precast high-strength concrete slabs and steel beams

Zhuangcheng Fang,Haibo Jiang,Gongfa Chen,Xiaotong Dong,Tengfei Shao 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.34 No.6

This study aims to examine the interface shear behavior between precast high-strength concrete slabs with pockets and steel beam to achieve accelerated bridge construction (ABC). Twenty-six push-out specimens, with different stud height, stud diameter, stud arrangement, deck thickness, the infilling concrete strength in shear pocket (different types of concrete), steel fiber volume of the infilling concrete in shear pocket concrete and casting method, were tested in this investigation. Based on the experimental results, this study suggests that the larger stud diameter and higher strength concrete promoted the shear capacity and stiffness but with the losing of ductility. The addition of steel fiber in pocket concrete would promote the ductility effectively, but without apparent improvement of bearing capacity or even declining the initial stiffness of specimens. It can also be confirmed that the precast steel-concrete composite structure can be adopted in practice engineering, with an acceptable ductility (6.74 mm) and minor decline of stiffness (4.93%) and shear capacity (0.98%). Due to the inapplicability of current design provision, a more accurate model was proposed, which can be used for predicting the interface shear capacity well for specimens with wide ranges of the stud diameters (from13 mm to 30 mm) and the concrete strength (from 26 MPa to 200 MPa).