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A Series Arc Fault Detection Strategy for Single-Phase Boost PFC Rectifiers
Cho, Younghoon,Lim, Jongung,Seo, Hyunuk,Bang, Sun-Bae,Choe, Gyu-Ha The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.6
This paper proposes a series arc fault detection algorithm which incorporates peak voltage and harmonic current detectors for single-phase boost power factor correction (PFC) rectifiers. The series arc fault model is also proposed to analyze the phenomenon of the arc fault and detection algorithm. For arc detection, the virtual dq transformation is utilized to detect the peak input voltage. In addition, multiple combinations of low- and high-pass filters are applied to extract the specific harmonic components which show the characteristics of the series arc fault conditions. The proposed model and the arc detection method are experimentally verified through a boost PFC rectifier prototype operating under the grid-tied condition with an artificial arc generator manufactured under the guidelines for the Underwriters Laboratories (UL) 1699 standard.
Cho, Junsang,Cheon, Wonjoong,Ahn, Sanghee,Jung, Hyunuk,Sheen, Heesoon,Park, Hee Chul,Han, Youngyih Oxford University Press 2017 Journal of radiation research Vol.58 No.5
<P><B>Abstract</B></P><P>Target motion–induced uncertainty in particle therapy is more complicated than that in X-ray therapy, requiring more accurate motion management. Therefore, a hybrid motion-tracking system that can track internal tumor motion and as well as an external surrogate of tumor motion was developed. Recently, many correlation tests between internal and external markers in X-ray therapy have been developed; however, the accuracy of such internal/external marker tracking systems, especially in particle therapy, has not yet been sufficiently tested. In this article, the process of installing an in-house hybrid internal/external motion-tracking system is described and the accuracy level of tracking system was acquired. Our results demonstrated that the developed in-house external/internal combined tracking system has submillimeter accuracy, and can be clinically used as a particle therapy system as well as a simulation system for moving tumor treatment.</P>
A Series Arc Fault Detection Strategy for Single-Phase Boost PFC Rectifiers
Younghoon Cho,Jongung Lim,Hyunuk Seo,Sun-Bae Bang,Gyu-Ha Choe 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.6
This paper proposes a series arc fault detection algorithm which incorporates peak voltage and harmonic current detectors for single-phase boost power factor correction (PFC) rectifiers. The series arc fault model is also proposed to analyze the phenomenon of the arc fault and detection algorithm. For arc detection, the virtual dq transformation is utilized to detect the peak input voltage. In addition, multiple combinations of low- and high-pass filters are applied to extract the specific harmonic components which show the characteristics of the series arc fault conditions. The proposed model and the arc detection method are experimentally verified through a boost PFC rectifier prototype operating under the grid-tied condition with an artificial arc generator manufactured under the guidelines for the Underwriters Laboratories (UL) 1699 standard.
Lim, Soyoung,Kim, Hyunuk,Selvapalam, Narayanan,Kim, Kyung-Jin,Cho, Sung June,Seo, Gon,Kim, Kimoon WILEY-VCH Verlag 2008 Angewandte Chemie Vol.47 No.18
<B>Graphic Abstract</B> <P>Holely organic solid: Effective packing of the rigid macrocycle cucurbituril through C&n.bond;H⋅⋅⋅O hydrogen-bonding and van der Waals interactions leads to a honeycomb-like structure with unprecedented stability and porosity. It shows extraordinary sorption properties toward gases, particularly acetylene, which are comparable or superior to those of metal–organic frameworks in terms of storage capacity. <img src='wiley_img/14337851-2008-47-18-ANIE200800772-content.gif' alt='wiley_img/14337851-2008-47-18-ANIE200800772-content'> </P>
성능 예측 상관식에 따른 쉐브론 형태 판형 열교환기 성능 특성 비교
배경진(Kyungjin Bae),안성국(Sungkuk An),조현욱(Hyunuk Cho),남상철(Sangchul Nam),조홍현(Honghyun Cho) 대한설비공학회 2011 설비공학 논문집 Vol.23 No.8
The performance of a plate heat exchanger for using liquid solution in the absorption chiller-heater was analyzed. The model was developed by using the various performance prediction correlations. The performance characteristics of the plate heat exchanger with the mass flow rate ratio was verified by using experimental data. To investigate performance of plate heat exchanger with geometry variables, the chevron angle, corrugated wave length, and corrugation depth were changed. As a result, the capacity of Kim and Martin correlation models was similar with the experimental data, and the capacity difference was less than 2%. Besides, the pressure drop of Marin correlation model showed a similar variation with experimental data, and the difference of pressure drop was less than 1.5 ㎪.
Jo, Jae-Ho,Singh, Nem,Kim, Donghyuk,Cho, Se Min,Mishra, Anurag,Kim, Hyunuk,Kang, Se Chan,Chi, Ki-Whan American Chemical Society 2017 Inorganic Chemistry Vol.56 No.14
<P>Coordination-driven self-assembly of m-bis[3-(4-pyridyl)pyrazolyl]xylene (L) and [(p-cymene)(2)Ru-2-(OO boolean AND OO)(2)(OTf)(2)] (A(1)) (OO boolean AND OO = 6,11-dioxido-5,12-naphthacenedione) in methanol resulted in a mixture of [2]catenane 1 and macrocyde 2, and self-assembly in nitromethane resulted in pure macrocycle 2, whereas the coordination-driven self-assembly of L and similar acceptors [(p-cymene)(2)Ru-2(OO boolean AND OO)(2)(OTf)(2)] [OO boolean AND OO = 5,8-dioxido-1,4-naphthoquinonnato (A(2)); 2,5-dioxido-1,4-benzoquinonato (A(3)); oxalato (A(4))] resulted in the formations of monomeric macrocydes 3-5, respectively. All self-assembled macrocydes were obtained in excellent yields (>90%) as triflate salts and were fully characterized by multinuclear NMR, elemental analysis, and electrospray ionization mass spectrometry (ESI-MS). The structures of [2]catenane 1 and macrocydes 5 were confirmed by single-crystal X-ray diffraction analysis. The X-ray structure of 1 confirmed an edge-to-face interaction between the tetracene moiety in parallel-displaced pi-pi stacks (3.5 angstrom), and CH center dot center dot center dot pi (2.5 angstrom) stabilizes the [2]catenane topology. Macrocydes 2-5 were assessed for anticancer activities using human cancer cell lines of different origins, and the macrocyde 3 was found to exhibit the best inhibitory effect and to do so in a dose-dependent manner. Further examination with the Tali apoptosis assay suggested the growth inhibitory effect of 3 involved the induction of the programmed cell death, and this suggestion was supported by observations of PARP and caspase 3 cleavage after treating cells with 3. In addition, exposure to 3 increased the expression of Bax and repressed the expression of Bcl-2, thus indicating the involvement of macrocyde 3 upstream of Bax and Bcl-2 in the apoptotic signaling pathway. Macrocycle 3 also tended to repress metastasis as evidenced by changes in the transcriptional expressions E- and N-cadherin (markers of metastasis). Furthermore, a stability assay demonstrated macrocyde 3 remained stable at high concentration.</P>
노의진,수비얀토,Wanuk Choi,박영철,Churl-Hee Cho,Hyunuk Kim 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.3
Due to their large surface areas and unique gas adsorption properties, mixed-matrix membranes (MMMs) with metal?organic frameworks (MOFs) have been extensively studied in relation to various gas separations. In the present paper, we report the quick synthesis of MOF-74 (M = Mg, Mn, Co, Ni) nanocrystals by microwave reactions and the fabrication of MMMs for use in CO2/N2 and O2/N2 separation. The scanning electron microscopy and energy dispersive X-ray spectroscopy analysis revealed the homogenous distribution of the MOF-74 nanocrystals within the polydimethylsiloxane (PDMS). The single gas permeation experiments showed the enhanced CO2/N2 and O2/N2 selectivity by adding the MOF-74 nanocrystals to the PDMS. This enhanced CO2/N2 and O2/N2 selectivity may be due to the affinity of CO2 and O2 toward the Lewis acidic sites of the MOF-74.