Prototype and Test of A Dual-stator PM Vernier Machine for Direct-drive Systems

Fei Zhao(조비),Byung-il Kwon(권병일) 대한전기학회 2015 대한전기학회 학술대회 논문집 Vol.2015 No.7

A Novel Two-phase U-core PMSM with Torque Ripple Reduction Method

Fei ZHAO(조비),Hai Lin(하이린),Thomas Anthony Lipo,Byung-il Kwon(권병일) 대한전기학회 2012 대한전기학회 학술대회 논문집 Vol.2012 No.11

Multi-layer 2D Simulation for an Axial-flux PM Vernier Machine Performance Estimation

Fei Zhao(조비),Byung-Il Kwon(권병일) 대한전기학회 2014 대한전기학회 학술대회 논문집 Vol.2014 No.4

Fabrication of CdSeS Alloyed Quantum Dots and Study on Fluorescence Lifetime

Zhao, Fei,Kim, Jong Sung Informa UK (TaylorFrancis) 2012 Molecular Crystals and Liquid Crystals Vol.566 No.1

Effect of the microstructure of Ag catalysts in the fabricating process of silicon nanowires

Fei Zhao,Guo-an Cheng,Rui-ting Zheng,Le-yang Xia 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.-

In this paper, well-aligned silicon nanowire (SiNW) arrays have been directly synthesized on single crystal silicon wafer at room temperature via a simple chemical etching method, and the effect of the microstructure of Ag catalysts on the fabricating process of the silicon nanowires has been systematically investigated. The experimental results show that different microstructures of Ag catalysts have been observed with different concentration of AgNO3/HF solution for different deposition times. The diameters of Ag particles and the mean interstitial sizes among Ag particles are relatively small for a short deposition time, and some large particles are formed when the deposition time increases. A much longer deposition time caused the substrate to be covered with a large amount of Ag dendrite. It can be inferred that 4 min is a good deposition time, because of the proportioned structure of particles and interstitial size, according to our experimental results. Nanostructures of Ag catalyst also vary with a change of concentration of AgNO3/HF solution. Ag dendrite may be formed at high concentration and affect the fabrication of SiNWs. In this paper, well-aligned silicon nanowire (SiNW) arrays have been directly synthesized on single crystal silicon wafer at room temperature via a simple chemical etching method, and the effect of the microstructure of Ag catalysts on the fabricating process of the silicon nanowires has been systematically investigated. The experimental results show that different microstructures of Ag catalysts have been observed with different concentration of AgNO3/HF solution for different deposition times. The diameters of Ag particles and the mean interstitial sizes among Ag particles are relatively small for a short deposition time, and some large particles are formed when the deposition time increases. A much longer deposition time caused the substrate to be covered with a large amount of Ag dendrite. It can be inferred that 4 min is a good deposition time, because of the proportioned structure of particles and interstitial size, according to our experimental results. Nanostructures of Ag catalyst also vary with a change of concentration of AgNO3/HF solution. Ag dendrite may be formed at high concentration and affect the fabrication of SiNWs.

DNA end resection and its role in DNA replication and DSB repair choice in mammalian cells

Zhao Fei,김우태,Kloeber Jake A.,Lou Zhenkun 생화학분자생물학회 2020 Experimental and molecular medicine Vol.52 No.-

DNA end resection has a key role in double-strand break repair and DNA replication. Defective DNA end resection can cause malfunctions in DNA repair and replication, leading to greater genomic instability. DNA end resection is initiated by MRN-CtIP generating short, 3′-single-stranded DNA (ssDNA). This newly generated ssDNA is further elongated by multiple nucleases and DNA helicases, such as EXO1, DNA2, and BLM. Effective DNA end resection is essential for error-free homologous recombination DNA repair, the degradation of incorrectly replicated DNA and double-strand break repair choice. Because of its importance in DNA repair, DNA end resection is strictly regulated. Numerous mechanisms have been reported to regulate the initiation, extension, and termination of DNA end resection. Here, we review the general process of DNA end resection and its role in DNA replication and repair pathway choice.

Preparation and Photocatalytic Performance of One-Dimensional In2O3 Nanofibers, CuO Microfibers and CuO/In2O3 Heterostructured Nanofibers by Electrospinning Process

Fei Zhao,Qifang Lu,Zhiliang Xiu,Chaofeng Zhu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.4

One-dimensional (1D) CuO/In2O3 heterostructured nanofibers with the diameter of about 300 nm were successfully prepared through combining a facile single-capillary electrospinning with sintering process, and investigated by thermogravimetric and differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) techniques, etc. The photocatalytic activities were examined by degrading methylene blue (MB) under 500W xenon lamp, halogen lamp and mercury lamp irradiation, respectively. The heterostructured nanofibers exhibited a higher photocatalytic activity than P25-TiO2 under 500W xenon lamp irradiation due to the enhanced absorption for visible light and the efficient electron–hole separation and transportation. The single CuO microfibers and In2O3 nanofibers were also prepared as the control groups by the same method.

A Qualitative Case Study on the Academic Experience of Overseas Chinese College Students under Academic Probation in Korea

Zhao, Long-fei(조용비),Chang, Seok-jin(장석진) 학습자중심교과교육학회 2018 학습자중심교과교육연구 Vol.18 No.20

본 연구는 학사경고를 받은 재한 중국인 유학생들의 대학생활 경험을 심층적으로 탐색함으로써 중국유학생들의 대학생활 적응과 관련된 요인을 살펴보고자 하였다. 이를 위하여 A대학교에 재학 중인 중국유학생 8명을 대상으로 2017년3월 중순부터 2017년6월 중순까지 심층면담 후, 녹음 자료를 전사하고 그 내용에 대한 질적 사례분석을 실시한 결과, 중국인 유학생들이 대학생활 동안 경험하게 되는 핵심적인 어려움을 문화 및 환경의 변화, 언어적 장벽, 심리적 어려움, 새로운 대인관계이라는 네 가지 주제로 범주화할 수 있었다. 본 연구는 중국인 유학생들이 한국의 대학생활 동안 어떤 경험을 하게 되는지 그들의 목소리를 통해 보여주었으며, 이러한 연구결과가 재한 중국인 유학생들이 대학생활에 효과적으로 적응하도록 돕는 교육 및 상담적 접근에 시사하는 바를 논의하였다. The study aims to explore the underlying experience of Chinese college students receiving academic probation in Korea. To this end, the paper conducted a qualitative case study on eight overseas Chinese students being placed on academic probation at A University in Seoul from mid-March, 2017 to mid-June 2017, with the method of in-depth interviews on their academic experience. The results of the analysis are clarified into four major themes: cultural and environmental changes, language barriers, psychological difficulties, and new interpersonal relationships. The research provides a reliable frame for understanding the differences between Chinese and Korean education, as well as the fundamentals for overseas students adaptation to a foreign culture and academic life. Besides, it provides a basic reference for developing relevant countermeasures and programs to help future overseas college students in their adaptation in Korea.

Human Immunodeficiency Virus Type 1 Subtypes Prevalence in Central China

Zhao Fei,LI Wen-jie,Wang Zhe 연세대학교의과대학 2009 Yonsei medical journal Vol.50 No.5

Purpose: To study the epidemic characteristics, transmission sources and routes of various subtypes of human immunodeficiency virus type 1 (HIV-1) and sequence variations in Henan, central China. To provide theoretical foundation for Acquired Immune Deficiency Syndrome (AIDS) prevention strategy in this region where the primary HIV transmission route was through former paid blood donation. Materials and Methods: HIV-1 gene env and gag were amplified by nested polymerase chain reaction (PCR) from uncultured peripheral blood mononuclear cells (PBMCs) obtained from 1,287 HIV-1 confirmed samples in Henan. Results: Among 1,287 samples, 5 HIV-1 strains were found including subtypes B’ (95.9%), C (0.47%) and recombinant subtypes CRF 07_BC (1.09%), CRF 08_BC (1.79%) and CRF 01_AE (0.78%). Phylogenetic tree analysis found that 1,234 Henan subtype B’ were closely related to those commonly found in Thailand, and were distantly related to other international subtypes. The dominant strain in former blood plasma donors (FPDs) was subtype B’, and the dominant strains in sexual transmission were subtype B’ and BC. Among HIV patients who were most likely infected through routes other than paid blood donation, the percentage of non-B’ subtypes was much higher than those of FPD. Conclusion: These findings suggest that the prevailing strain of HIV-1 in Henan is subtype B’, similar to the B’ subtype found in Thailand. In addition, for the first time we found subtypes C and recombinant subtypes CRF07_BC, CRF08_BC and CRF01_AE in this region. Indicating that the subtype feature of HIV-1 became more complicated than before in central China. Purpose: To study the epidemic characteristics, transmission sources and routes of various subtypes of human immunodeficiency virus type 1 (HIV-1) and sequence variations in Henan, central China. To provide theoretical foundation for Acquired Immune Deficiency Syndrome (AIDS) prevention strategy in this region where the primary HIV transmission route was through former paid blood donation. Materials and Methods: HIV-1 gene env and gag were amplified by nested polymerase chain reaction (PCR) from uncultured peripheral blood mononuclear cells (PBMCs) obtained from 1,287 HIV-1 confirmed samples in Henan. Results: Among 1,287 samples, 5 HIV-1 strains were found including subtypes B’ (95.9%), C (0.47%) and recombinant subtypes CRF 07_BC (1.09%), CRF 08_BC (1.79%) and CRF 01_AE (0.78%). Phylogenetic tree analysis found that 1,234 Henan subtype B’ were closely related to those commonly found in Thailand, and were distantly related to other international subtypes. The dominant strain in former blood plasma donors (FPDs) was subtype B’, and the dominant strains in sexual transmission were subtype B’ and BC. Among HIV patients who were most likely infected through routes other than paid blood donation, the percentage of non-B’ subtypes was much higher than those of FPD. Conclusion: These findings suggest that the prevailing strain of HIV-1 in Henan is subtype B’, similar to the B’ subtype found in Thailand. In addition, for the first time we found subtypes C and recombinant subtypes CRF07_BC, CRF08_BC and CRF01_AE in this region. Indicating that the subtype feature of HIV-1 became more complicated than before in central China.

A Novel Two-Phase Permanent Magnet Synchronous Motor Modeling for Torque Ripple Minimization

Fei Zhao,Lipo, T. A.,Byung-Il Kwon IEEE 2013 IEEE transactions on magnetics Vol.49 No.5

<P>This paper proposes a novel two-phase, two-pole, permanent magnet synchronous motor (PMSM) with dual U-core stator structure for torque ripple minimization. The proposed motor is modeled based on the conventional single-phase U-core PMSM with approximate output power and core dimension. Torque ripple in the novel motor can be reduced significantly due to 90 <SUP>°</SUP> electrical angle phase shift in two sets of magnet pairs and 90<SUP>°</SUP> shift in two-phase excitation currents. Characteristics of both PMSMs such as back-EMF, cogging torque and electromagnetic torque are analyzed and compared by using the 3-D finite element analysis (FEA). As shown in the result, the cogging torque and torque ripple in the novel two-phase PMSM are efficiently reduced with sinusoidal back-EMF waveform and reasonable current density value. The validity of both PMSM models is also verified by the comparison between simulated and experimental measured results.</P>