단상 유도형 동기 전동기(LSPM)의 특성해석에 관한 연구

정대성,김승주,이진헌,최재학,이주,Jung, Dae-Sung,Kim, Seung-Ju,Lee, Jin-Hun,Choi, Jae-Hak,Lee, Ju 한국조명전기설비학회 2007 조명·전기설비학회논문지 Vol.21 No.3

가전분야에서의 전동기 효율향상을 통한 에너지 소비절감 효과는 상당히 크지만 이를 위한 전동기의 설계/해석 기술 확보가 아직은 미흡한 상태이다. 이에 따라 유도형 동기전동기가 제안되었지만, 유도형 동기 전동기는 유도전동기와 통기전동기의 특성을 동시에 가지고 있어, 해석 및 설계가 쉽지 않다. 따라서 본 논문에서는 기존의 냉장고 압축기용 전동기인 단상유도전동기를 대처할 수 있는 단상 유도형 동기전동기를 이용해 파라미터에 따라 특성이 어떻게 바뀌는가에 대해 서술하였다. 그에 따라 단상유도전동기의 정상상태 특성을 해석하고 제안모델의 성능을 기존모델과 비교하고 실험하여 해석결과의 신뢰성을 검증한다. 또한 본 논문에서는 제안모델의 기존 고정자 형상이나 권선 스팩을 유지하고 회전자의 형상이나 구조만을 변경시켜 성능향상을 도모하였다. 해석방법으로는 전자장 수치 해석적인 방법으로 널리 이용되고 있는 유한요소법(Finite Element Method : FEM)을 이용하였다. Electric motor efficient improvement from home appliance field is important to the effect reducing the energy consumption. But the electric motor design/analysis technology is still insufficient. Specially the electric motor design/analysis technology of satisfying characteristic of both the induction motor and the synchronous motor such as Line start permanent motor. Therefore the electric motor design/analysis technology is urgently demanded reliability. This paper proposes the sing1e-phase line-start permanent magnet motor to develop the motor it with be able to alternate the sing-phase induction motor it is a refrigerator compressor motor. The sing-phase induction motor is analyzed in the steady state. And we have a certification test to compare our single-phase line-start permanent magnet motor with the sing-phase induction motor. In order to improve the performance, the stator of the single-phase line-start permanent magnet motor is same as the stator of the sing-phase induction motor and changes the rotor form and has the permanent magnet. It used the Finite Element Method(FEM) which is widely used with electronic-magnetic field numerical analysis method.

Chrysin attenuates atopic dermatitis by suppressing inflammation of keratinocytes

Choi, Jin Kyeong,Jang, Yong Hyun,Lee, Soyoung,Lee, Sang-Rae,Choi, Young-Ae,Jin, Meiling,Choi, Jung Ho,Park, Jee Hun,Park, Pil-Hoon,Choi, Hyukjae,Kwon, Taeg Kyu,Khang, Dongwoo,Kim, Sang-Hyun Elsevier 2017 Food and chemical toxicology Vol.110 No.-

<P><B>Abstract</B></P> <P>We previously reported the inhibitory effect of chrysin, a natural flavonoid plentifully contained in propolis, vegetables and fruits, on the mast cell-mediated allergic reaction. In this study, we evaluated the effect of chrysin on atopic dermatitis (AD) and defined underlying mechanisms of action. We used an AD model in BALB/c mice by the repeated local exposure of 2,4-dinitrochlorobenzene (DNCB) and house dust mite (<I>Dermatophagoides farinae</I> extract, DFE) to the ears. Repeated alternative treatment of DNCB/DFE caused AD-like skin lesions. Oral administration of chrysin diminished AD symptoms such as ear thickness and histopathological analysis, in addition to serum IgE and IgG2a levels. Chrysin decreased infiltration of mast cells, and reduced serum histamine level. Chrysin also suppressed AD by inhibiting the inflammatory responses of Th1, Th2, and Th17 cells in mouse lymph node and ear. Interestingly, chrysin significantly inhibited the production of cytokines, Th2 chemokines, CCL17 and CCL22 by the down-regulation of p38 MAPK, NF-κB, and STAT1 in tumor necrosis factor (TNF)-α/interferon (IFN)-γ-stimulated human keratinocytes (HaCaT). Chrysin also inhibited TNF-α/IFN-γ-stimulated IL-33 expression in HaCaT cells and mouse primary keratinocytes. Taken together, the results indicate that chrysin suppressed AD symptoms, suggesting that chrysin might be a candidate for the treatment of AD and skin allergic diseases.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Chrysin suppresses AD symptoms by inhibiting T helper cell immune reaction. </LI> <LI> Chrysin downregulates CCL17 and CCL22 expression via p38 MAPK, STAT1, and NF-κB in human keratinocytes. </LI> <LI> Chrysin and tacrolimus have overlapping effects in inhibiting AD immune responses. </LI> <LI> Chrysin might be a candidate for the treatment of skin allergic diseases. </LI> </UL> </P>

THREE DIMENSIONAL ATOM PROBE STUDY OF NI-BASE ALLOY/LOW ALLOY STEEL DISSIMILAR METAL WELD INTERFACES

Choi, Kyoung-Joon,Shin, Sang-Hun,Kim, Jong-Jin,Jung, Ju-Ang,Kim, Ji-Hyun Korean Nuclear Society 2012 Nuclear Engineering and Technology Vol.44 No.6

Three dimensional atom probe tomography (3D APT) is applied to characterize the dissimilar metal joint which was welded between the Ni-based alloy, Alloy 690 and the low alloy steel, A533 Gr. B, with Alloy 152 filler metal. While there is some difficulty in preparing the specimen for the analysis, the 3D APT has a truly quantitative analytical capability to characterize nanometer scale particles in metallic materials, thus its application to the microstructural analysis in multi-component metallic materials provides critical information on the mechanism of nanoscale microstructural evolution. In this study, the procedure for 3D APT specimen preparation was established, and those for dissimilar metal weld interface were prepared near the fusion boundary by a focused ion beam. The result of the analysis in this study showed the precipitation of chromium carbides near the fusion boundary between A533 Gr. B and Alloy 152.

NANO-STRUCTURAL AND NANO-CHEMICAL ANALYSIS OF NI-BASE ALLOY/LOW ALLOY STEEL DISSIMILAR METAL WELD INTERFACES

Choi, Kyoung-Joon,Shin, Sang-Hun,Kim, Jong-Jin,Jung, Ju-Ang,Kim, Ji-Hyun Korean Nuclear Society 2012 Nuclear Engineering and Technology Vol.44 No.5

The dissimilar metal joints welded between Ni-based alloy, Alloy 690 and low alloy steel, A533 Gr. B with Alloy 152 filler metal were characterized by using optical microscope, scanning electron microscope, transmission electron microscope, secondary ion mass spectrometry and 3-dimensional atom probe tomography. It was found that in the weld root region, the weld was divided into several regions including unmixed zone in Ni-base alloy, fusion boundary, and heat-affected zone in the low alloy steel. The result of nanostructural and nanochemical analyses in this study showed the non-homogeneous distribution of elements with higher Fe but lower Mn, Ni and Cr in A533 Gr. B compared with Alloy 152, and the precipitation of carbides near the fusion boundary.

Biological Activity of Citrus pseudogulgul, Citrus hassaku Hort., and Citrus medica Extracts During Maturation

Sang Suk Kim(김상숙),Suk Man Park(박석만),Hyun Joo An(안현주),Su Hyun Yoon(윤수현),Jae Ho Park(박재호),Kyung Jin Park(박경진),Young Hun Choi(최영훈) 한국원예학회 2015 한국원예학회 학술발표요지 Vol.2015 No.10

Anti-cancer Effect of Glabridin via Decreased Extracellular Vesicles Secretion in MDA-MB 231 Human Breast Cancer Cells

Sang-Hun Choi,Jin-Hyeon Hwang,Kun Ho Son,Young-Eun Cho 한국식품영양과학회 2020 한국식품영양과학회 학술대회발표집 Vol.2020 No.10

Imidazole Antifungal Drugs Inhibit the Cell Proliferation and Invasion of Human Breast Cancer Cells

( Sung Hun Bae ),( Ju Ho Park ),( Hyeon Gyeom Choi ),( Hyesook Kim ),( So Hee Kim ) 한국응용약물학회 2018 Biomolecules & Therapeutics(구 응용약물학회지) Vol.26 No.5

Breast cancer is currently the most prevalent cancer in women, and its incidence increases every year. Azole antifungal drugs were recently found to have antitumor efficacy in several cancer types. They contain an imidazole (clotrimazole and ketoconazole) or a triazole (fluconazole and itraconazole) ring. Using human breast adenocarcinoma cells (MCF-7 and MDA-MB-231), we evaluated the effects of azole drugs on cell proliferation, apoptosis, cell cycle, migration, and invasion, and investigated the underlying mechanisms. Clotrimazole and ketoconazole inhibited the proliferation of both cell lines while fluconazole and itraconazole did not. In addition, clotrimazole and ketoconazole inhibited the motility of MDA-MB-231 cells and induced G1-phase arrest in MCF-7 and MDA-MB-231 cells, as determined by cell cycle analysis and immunoblot data. Moreover, Transwell invasion and gelatin zymography assays revealed that clotrimazole and ketoconazole suppressed invasiveness through the inhibition of matrix metalloproteinase 9 in MDA-MB-231 cells, although no significant changes in invasiveness were observed in MCF-7 cells. There were no significant changes in any of the observed parameters with fluconazole or itraconazole treatment in either breast cancer cell line. Taken together, imidazole antifungal drugs showed strong antitumor activity in breast cancer cells through induction of apoptosis and G1 arrest in both MCF-7 and MDA-MB-231 cells and suppression of invasiveness via matrix metalloproteinase 9 inhibition in MDA-MB-231 cells. Imidazole drugs have well-established pharmacokinetic profiles and known toxicity, which can make these generic drugs strong candidates for repositioning as antitumor therapies.

Long-term results of conjoined unification venoplasty for multiple portal vein branches of the right liver graft in living donor liver transplantations

Sung-Gyu Lee,Shin Hwang,Tae Yong Ha,Gi Won Song,Dong-Hwan Jung,Gil-Chun Park,Chul-Soo Ahn,Deok-Bog Moon,Ki Hun Kim,Young-In Yoon,Yo Han Park,Hui-Dong Cho,Yong-Kyu Chung,Sang-Hyun Kang,Jin-Uk Choi,Sung 대한이식학회 2019 Korean Journal of Transplantation Vol.33 No.4

Background: Autologous portal vein Y-graft (PYG) interposition has been the standard procedure for reconstruction of double portal vein (PV) orifices of right liver grafts during living donor liver transplantations. However, it has the disadvantage of being vulnerable to anastomotic stenosis. A refined technique of conjoined unification venoplasty (CUV) was developed to secure PV reconstruction. Methods: We reviewed the surgical outcomes in PV reconstructions using CUVs in 21 cases which were followed up for >3 years. Results: The mean age of recipients was 51.7±4.9 years. The model for end-stage liver disease score was 15.3±6.4. The graft-recipient weight ratio was 1.12±0.21. Recipient PYGs were harvested in all cases. All living donors were blood relatives or relatives through marriage with type III PV anomalies. The number of right liver graft PV orifices was two in 19 cases and three in two cases. For the central intervening vein patch, a PV segment was used in six cases, and an autologous greater saphenous vein patch was used in the remaining 15 cases. The 21 patient cohort displayed a 100% 4-year patient survival rate. None of them underwent any PV interventions including interventional stenting. Serial follow-up computed tomography scans revealed that the reconstructed PV showed early reshaping with a stable streamlined configuration for over 3 years. Conclusions: PV reconstruction using the CUV technique appears to be significantly more effective in preventing PV complications. We believe that CUV is a useful technique to reconstruct right liver grafts with multiple PV orifices.

Pathogenic microorganisms, heavy metals, and antibiotic residues in seven Korean freshwater aquaculture species

Choi, Jae-Suk,Park, Sun-Mee,Kim, Young Hun,Oh, Sang Cheol,Lim, Eun Seo,Hong, Yong-Ki,Kim, Mi-Ryung Korean Society of Food Science and Technology 2016 Food Science and Biotechnology Vol.25 No.5

This survey was performed to estimate the levels of pathogenic microorganisms, antibiotic residues, and heavy metals in seven Korean freshwater aquaculture species including Anguilla japonica, Cyprinus carpio nudus, Oncorhynchus mykiss, Pseudobagrus fulvidraco, Semisulcospira coreana, Silurus asotus, and Trionyxs sinensis. None of the ten foodborne pathogens tested in this study were found in any of the species collected from any of the aquaculture farms. Furthermore, no banned chemicals or antibiotic residues were found in any of the species collected from any of the aquaculture farms, except enrofloxacin, which was below guideline limits (0.1 mg/kg). Finally, no species had lead, cadmium, total arsenic, or total mercury concentrations above the Ministry of Food and Drug Safety (MSDF) guidelines (0.5, 0.5, 0.1, and 0.5 mg/kg, respectively). These results ensure the safety of freshwater aquaculture species and will be useful for developing consumption advisories of freshwater fishes.

Naphthalene diimide-based small molecule acceptors for fullerene-free organic solar cells

Sung, Min Jae,Huang, Minjuan,Moon, Sang Hun,Lee, Tack Ho,Park, Song Yi,Kim, Jin Young,Kwon, Soon-Ki,Choi, Hyosung,Kim, Yun-Hi Elsevier 2017 SOLAR ENERGY -PHOENIX ARIZONA THEN NEW YORK- Vol.150 No.-

<P><B>Abstract</B></P> <P>Non-fullerene acceptors have attracted great attention as an alternative to fullerene derivatives to overcome their disadvantages such as limited molecular design due to fullerene moiety, electronic tuning via structural modification, and weak absorption in the visible range. In this work, we design a new class of naphthalenediimide (NDI)-based small molecule acceptors by introducing an NDI central core unit and A-D-A-D-A-type moiety. The NDI-TR is a promising material as an electron acceptor for OSCs because of many advantages including high electron affinity and electron mobility, and well-matched energy levels with polymer donors. The device based on NDI-TR had the highest fill factor (0.69) and power conversion efficiency (3.07%) among fullerene-free organic solar cells with NDI small molecule acceptors. This high device efficiency may be attributed to improved charge transport and minimized bimolecular recombination due to the smooth surface roughness and pronounced face-on orientation of polymer backbones in the bulk heterojunction film.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We synthesized new class of NDI-based small molecule acceptors. </LI> <LI> NDI-based small molecule acceptors have many advantages including high electron affinity and electron mobility, and well-matched energy levels with polymer donors. </LI> <LI> The device with NDI-TR had the highest FF and PCE among fullerene-free organic solar cells with NDI small molecule acceptors. </LI> <LI> Improved charge transport and minimized bimolecular recombination by smooth surface roughness and pronounced face-on orientation of polymer backbones resulted in high device efficiency. </LI> </UL> </P>