A GAPSO-Enhanced Extreme Learning Machine Method for Tool Wear Estimation in Milling Processes Based on Vibration Signals

Zhi Lei,Qinsong Zhu,Yuqing Zhou,Bintao Sun,Weifang Sun,Xiaoming Pan 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.3

Tools are the most vulnerable components in milling processes conducted using numerical control milling machines, and their wear condition directly influences work-product quality and operational safety. As such, tool wear estimation is an essential component of NC milling operations. This study addresses this issue by proposing an extreme learning machine (ELM) method enhanced by a hybrid genetic algorithm and particle swarm optimization (GAPSO) approach for conducting tool wear estimation based on workpiece vibration signals. Here, a few feature parameters in the time, frequency, and time–frequency (Ensemble empirical mode decomposition, EEMD) domains of the workpiece vibration signals are extracted as the input of the ELM model. Then, the initialized weights and thresholds of the ELM model are optimized based on the GAPSO approach with training dataset. Finally, tool wear is estimated using the optimized ELM model with testing dataset. The effectiveness of the proposed method is verified by its application to vibration signals collected from two milling tool wear experiments (an open-access benchmark dataset and a milling tool wear experiment) by comparison to the ELM, GA-ELM, and PSO-ELM methods. The results indicate that the estimation accuracy and optimization efficiency of the proposed method outperforms that of other three methods.

Improved Resistance Switching Characteristics of BiFeO3 Thin Film by Increasing the Annealing Temperature

Zhilei Miao,Wei Wang,Rongchun Yuan,Jun Zhu,Shudong Wu,Haitao Chen,Xianghua Zeng,Qiang Wang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.09

We have fabricated BiFeO3 thin film deposited on Pt/Ti/SiO2/Si substrates by the chemical solution deposition method. The effects of annealing temperature on the thin film structure, resistance switching (RS) properties, conduction mechanisms are investigated. It exhibits improved RS window with high ON/OFF ratio ( ~10 4) for the sample annealed at 650 ℃. XPS characterization indicates that cation ratio of Fe2+/Fe3+ is increased with increasing annealing temperature. Crystal lattice distortion generated by Fe2+ cations, along with oxygen vacancies, commonly contribute to opening the RS window and the increment of conductive filaments. The film's conduction mechanisms under different annealing temperatures are fully discussed. The RS properties of this system can be effectively improved by increasing the annealing temperature, which is crucial prerequisite for future applications of BFO-based thin film device in resistance random access memory.

Study on properties of geopolymer-polyurethane sponge composite

Zhilei Chen,이상진 한양대학교 세라믹연구소 2018 Journal of Ceramic Processing Research Vol.19 No.5

A newly conceived geopolymer composite was fabricated by a combination of the geopolymer and polyurethane sponge. Thedensity and porosity of hardened geopolymer composite, corresponded to different pore sizes of polyurethane sponge, exhibitedno significant differences from each other. However, the mechanical behavior, the compressive strength and flexural strength,showed slight differences accordingly. Fracture of the geopolymer composite exposed to high compressive load was notobserved from all specimens containing polyurethane sponge. The toughness enhancement of the geopolymer composite, dueto spontaneous elasticity of polyurethane sponge, crack spread, and crack diffraction, was identified through the stress-straincurve and microstructure of fracture surface. The newly designed geopolymer composite having a 3-dimensional spongeskeleton showed relatively higher flexural strength of 8.0MPa than other conventional geopolymer composites.

A Research of Gender Role Stereotypes of Chinese Leading Cadres

( Zhao Zhilei ) 전남대학교 사회과학연구소 2020 현대사회과학연구 Vol.24 No.-

주관적인 심리적 요인을 조사하는 Q 방법론은 중국 주요 간부들의 성 역할 고정관념을 측정한 후, 성 역할을 분류하고 그 특성을 분석하고자 하였다. 본 연구는 응답자의 주관적 진술과 문헌에서 47개의 표본을 개발하며, 무작위 표본 추출을 사용하여 47명의 응답자를 P 표본으로 선정하였다. 연구 결과에 따르면, 첫째 남녀 양성 역할이 주요 간부들 사이에서 가장 높은 비중을 차지하며, 그 다음이 남성 역할과 여성 역할이 순서대로 뒤를 이었다. 둘째, 성 역할에서 각기 다른 유형의 주요 간부들 사이에 분명한 차이가 있고, 남성 성 점수가 여성 성 점수에 비해 상당히 높으며, 주요 간부 그룹 간에서 남성적 고정관념이 존재한다. 셋째, 풀뿌리 수준에서 주요 간부들 사이에서 남성성이 더 두드러진다. Q methodology which probes into subjective psychological factors is used to measure gender role stereotypes of Chinese leading cadres, then gender roles are categorized, and their characteristics are analyzed and studied. This article develops 47 samples from the subjective statements of respondents and the original texts of classic literature, and random sampling is used to select 47 respondents as P samples. The research found: first, androgynous role occupies the highest proportion among leading cadres, followed by masculine role and feminine role in order; second, there are obvious differences between different types of leading cadres in gender role, masculinity score is significantly higher than that of their femininity, and there are masculine stereotypes among the group of leading cadres; third, masculinity is more conspicuous among leading cadre at grass-roots level.

Antifungal mechanisms of ε-poly-L-Lysine with different molecular weights on Saccharomyces cerevisiae

Ying Hou,Fengping Wang,Zhilei Tan,Jiandong Cui,Shiru Jia 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.3

ε-Poly-L-lysine (ε-PL) is a natural antimicrobial cationic peptide. Antimicrobial activity of ε-PL is closely related to its molecular weight (Mw). However, the antimicrobial mechanisms of ε-PL with different Mws are still vague. In this study, Saccharomyces cerevisiae was used as the model system to analyze the mechanism from these three aspects: cell wall, cell membrane, and metabolism. The results showed that high-Mw ε-PL (1-3 kDa and >3 kDa) and commercial ε-PL product caused cell wall lesions, and significantly improved cell membrane permeability compared to low-Mw ε-PL (<1 kDa), resulting in leaking of the protoplasm through the pores and cell death. Furthermore, metabolomics analysis showed that high-Mw ε-PL (1-3 kDa and >3 kDa) and product displayed higher inhibition effect on the glycolysis pathway and tricarboxylic cycle than that of low-Mw ε-PL (<1 kDa).

Modeling and Virtual Screening of Antisense Peptides Targeting the Divergent Region of Tumor-Associated MT1-MMP Protein

Bowen Tan,Yijie Zhou,Zhilei Song,Yinxuan Peng,Fang Wu,Yue Kang,Xiaomin Liu,Li Zeng,Tingting Huang,Zongying Liu,Lili Xiong,Zhiyun Guo,Jian Cui,Canquan Mao 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.9

Membrane type-1 matrix metalloproteinase (MT1-MMP; also known as MMP14) is a key enzyme involved in tumor invasion and metastasis, and is a potential target for drug discovery for cancer therapy. However, till now there is no MT1-MMP- or MMP-based anticancer drugs in the market mainly because of the high conservation of the MMP family and also because there is no elucidated crystal structure for the mature MT1-MMP. The modeling of the three-dimensional structure of mature MT1-MMP and the finding of MT1-MMP targeted peptides by virtual screening are highly desired. In this study, the three-dimensional structure of mature MT1-MMP is constructed by homology and de novo modeling and later rationalized and optimized by molecular dynamics simulations. An antisense peptide library was constructed against the divergent sense peptide DEGTEEET in the specific region of MT1-MMP, which was found by multiple alignment of the whole MMP family. The antisense peptide library was virtually screened against the constructed three-dimensional model of MT1-MMP. The top 20 novel peptides were further studied, which were found well docked with MT1-MMP at the region of DEGTEEET, again confirming their specific binding to MT1-MMP. Preliminary study of one of the top-ranked peptide SFLLSPFV showed that it could inhibit the viabilities of MG63 and MDA-MB-231 tumor cells. We thus not only successfully modeled the three-dimensional structure of mature MT1-MMP but also provided a new way for the finding of peptide candidates targeting MT1-MMP based on antisense peptide library.

MiR-29a and MiR-140 Protect Chondrocytes against the Anti-Proliferation and Cell Matrix Signaling Changes by IL-1β

Li, Xianghui,Zhen, Zhilei,Tang, Guodong,Zheng, Chong,Yang, Guofu Korean Society for Molecular and Cellular Biology 2016 Molecules and cells Vol.39 No.2

As a degenerative joint disease, osteoarthritis (OA) constitutes a major cause of disability that seriously affects the quality of life of a large population of people worldwide. However, effective treatment that can successfully reverse OA progression is lacking until now. The present study aimed to determine whether two small non-coding RNAs miR-29a and miR-140, which are significantly down-regulated in OA, can be applied together as potential therapeutic targets for OA treatment. MiRNA synergy score was used to screen the miRNA pairs that potentially synergistically regulate OA. An in vitro model of OA was established by treating murine chondrocytes with IL-$1{\beta}$. Transfection of miR-29a and miR-140 via plasmids was investigated on chondrocyte proliferation and expression of nine genes such as ADAMTS4, ADAMTS5, ACAN, COL2A1, COL10A1, MMP1, MMP3, MMP13 and TIMP metallopeptidase inhibitor 1 (TIMP1). Western blotting was used to determine the protein expression level of MMP13 and TIMP1, and ELISA was used to detect the content of type II collagen. Combined use of miR-29a and miR-140 successfully reversed the destructive effect of IL-$1{\beta}$ on chondrocyte proliferation, and notably affected the MMP13 and TIMP1 gene expression that regulates extracellular matrix. Although co-transfection of miR-29a and miR-140 did not show a synergistic effect on MMP13 protein expression and type II collagen release, but both of them can significantly suppress the protein abundance of MMP13 and restore the type II collagen release in IL-$1{\beta}$ treated chondrocytes. Compared with single miRNA transfection, cotransfection of both miRNAs exceedingly abrogated the suppressed the protein production of TIMP1 caused by IL-$1{\beta}$, thereby suggesting potent synergistic action. These results provided1novel insights into the important function of miRNAs' collaboration in OA pathological development. The reduced MMP13, and enhanced TIMP1 protein production and type II collagen release also implies that miR-29a and miR-140 combination treatment may be a possible treatment for OA.

MiR-29a and MiR-140 Protect Chondrocytes against the Anti-Proliferation and Cell Matrix Signaling Changes by IL-1beta

Guofu Yang,Xianghui Li,Zhilei Zhen,Guodong Tang,Chong Zheng 한국분자세포생물학회 2016 Molecules and cells Vol.39 No.2

As a degenerative joint disease, osteoarthritis (OA) constitutes a major cause of disability that seriously af-fects the quality of life of a large population of people worldwide. However, effective treatment that can successfully reverse OA progression is lacking until now. The present study aimed to determine whether two small non-coding RNAs miR-29a and miR-140, which are significantly down-regulated in OA, can be applied together as potential therapeutic targets for OA treatment. MiRNA synergy score was used to screen the miRNA pairs that potentially synergistically regulate OA. An in vitro model of OA was established by treating murine chondrocytes with IL-1. Transfection of miR-29a and miR-140 via plasmids was investigated on chondrocyte proliferation and expression of nine genes such as ADAMTS4, ADAMTS5, ACAN, COL2A1, COL10A1, MMP1, MMP3, MMP13 and TIMP metallopeptidase inhibitor 1 (TIMP1). Western blotting was used to determine the protein expression level of MMP13 and TIMP1, and ELISA was used to detect the content of type II collagen. Combined use of miR-29a and miR-140 successfully reversed the destructive effect of IL-1 on chondrocyte proliferation, and notably affected the MMP13 and TIMP1 gene expression that regulates extracellular matrix. Although co-transfection of miR-29a and miR-140 did not show a synergistic effect on MMP13 protein expression and type II collagen release, but both of them can significantly suppress the protein abun-dance of MMP13 and restore the type II collagen release in IL-1 treated chondrocytes. Compared with single miRNA transfection, co-transfection of both miRNAs exceedingly abrogated the suppressed the protein production of TIMP1 caused by IL-1, thereby suggesting potent synergistic action. These results provided novel insights into the important function of miRNAs' collaboration in OA pathological development. The reduced MMP13, and enhanced TIMP1 protein production and type II collagen release also implies that miR-29a and miR-140 combination treatment may be a possible treatment for OA.

A Novel Model for Mechanics and Safety Calculation of Pipe Roof Based on the Load Transfer Mechanism

Yang Zhou,Hongpeng Lai,Yuanpei Chen,Zhilei Li 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.12

A novel model is created in this paper to realize the systematic evaluation of the mechanical properties and construction safety of the pipe roof support system. The pipe roof is split into supported area, unloading area, and stable area based on the load distribution characteristics. Combining a statically indeterminate beam (for the area of unloading) with an elastic foundation beam (supported area and stability area) takes into account the mechanical effect of the pipe roof. The new model can better reflect the load transfer mechanism and the stability of the tunnel face under the pre-support. It is demonstrated that the novel model, when compared to the existing theoretical solution, is more closely related to the measured and simulated results than typical engineering cases and is practical for field application. It can provide a new idea for the design of pipe roof support and the safety evaluation of field construction.

Rectifying resistance switching behaviors of SnO2 microsphere films modulated by top electrodes

Rongchun Yuan,Weiwei Xia,Mengxue Xu,Zhilei Miao,Shudong Wu,Xiuyun Zhang,Junhui He,Qiang Wang 한국물리학회 2020 Current Applied Physics Vol.20 No.3

Based on the bipolar resistive switching (RS) characteristics of SnO2 films, we have fabricated a new prototypical device with sandwiched structure of Metal/SnO2/fluorine-doped tin oxide (FTO). The SnO2 microspheres film was grown on FTO glass by template-free hydrothermal synthesis, which was evaporated with various commonly used electrodes such as aluminium (Al), silver (Ag), and gold (Au), respectively. Typical self-rectifying resistance switching behaviors were observed for the RS devices with Al and Au electrodes. However, no obvious rectifying resistance switching behavior was observed for the RS device with Ag electrode. Above results were interpreted by considering the different interface barriers between SnO2 and top metal electrodes. Our current studies pave the ways for modulating the self-rectifying resistance switching properties of resistive memory devices by choosing suitable metal electrodes.