온도 유지시간 제어를 적용한 하이브리드 분말 압출 공정을 통한 요구 특성의 스퍼기어 제조

이경훈(Kyung Hun Lee),황대원(Dae Won Hwang),김병민(Byung Min Kim) 대한기계학회 2011 大韓機械學會論文集A Vol.35 No.8

본 연구는 압출 시 성형온도를 유지하여 Zn-22Al 합금분말의 성형성을 향상시키는 하이브리드 분말 압출 공정의 개발 및 온도 유지시간이 압출된 스퍼기어의 기계적 특성에 미치는 영향을 조사하기 위해 수행되었다. 피치원 지름 1.8mm 의 소형 스퍼기어는 압출온도 290, 300, 310℃에서 성형되었다. 볼밀시간 32h 의 Zn-22Al 합금분말을 압출온도 310℃에서 압출 시 표면 결함이 없는 소형 기어가 제조되었다. 경도분포는 기어 중심부와 치형부에서 불균일하였고 소결공정 후 내부 변형에너지의 차이로 인해 내부균열이 발생하였다. 위와 같은 문제를 해결하기 위해 온도 유지시간 제어를 이용한 하이브리드 압출 연구를 수행하였다. 압출된 스퍼기어의 평가는 압출하중, 비커스 경도 및 치수정밀도 측정을 통해 이루어졌다. 온도 유지시간 15min 에서 압출된 스퍼기어의 기계적 성질이 가장 우수하였다. In this study, a hybrid powder-extrusion process involving the control of temperature dwelling time for improving the formability of Zn-22Al powder was developed and the effect of dwelling time on the mechanical properties of a spur gear with a pitch circle having a diameter of 1.8 mm was investigated. General extrusion experiments were carried out at different temperatures such as 290, 300, and 310°C. Spur gears with good qualities and without any surface defects were obtained in the case of extrusion temperature of 310°C and ball-milling duration of 32 h. The Vickers hardness distribution was non-uniform, and after the sintering process, an internal crack was generated because of the different deformation energy between gear central part and teeth. To overcome the abovementioned problems, research on controlling the dwelling time of the extrusion temperature in the powder-extrusion process was carried out. Good-quality spur gears were obtained when the dwelling time was 15 min.

Improvement and Application for Environmental Conservation Value Assessment Map(ECVAM) of Nationwide Land in Korea

Lee, Moung-Jin,Jeon, Seong-Woo,Jo, Min-Jeong,Song, Won-Kyong,Kang, Byung-Jin The Korean Society of Remote Sensing 2007 大韓遠隔探査學會誌 Vol.23 No.5

This study is aiming at improving the Environmental Conservation Value Assessment Map(ECVAM) of National Land in Korea. The ECVAM items are composed of legal and environmental/ecological assessments. A popular method applied to ECVAM is an overlay environmental/ecological assessment items. The purpose of this study is to offer complementary items of the ECVAM by examining assessment items. In this study we assessed the ECVAM by five methods. Method 1 is Grade 1 areas of each administrative district; Method 2 is comparing overlapped areas of each assessment items Grade 1, 2 and permission of each assessment items duplication; Method 3 is Grade 1, 2 areas by only singular assessment items; Method 4 is Grade 1 areas only of Method 2; and Method 5 is Grade 2 areas only of Method 2. Method 1 showed Seoul and other metropolitan cities revealed a large proportion of Grade I regions by the legal assessment items. Gang won-Do, showed a large proportion of Grade I regions by the environmental/ecological assessment item. Method 2 showed 93.4% of diameter Grade II(standard for stability); forest diameter item accounted for 99.9% by Method 3, Method 4 showed 95.7% of forest diameter, and forest density accounted for 66.4% by Method 5. This study contributes to reduce the complexity in the process of manufacturing ECVAM of National Land, and to raise the flexibility in the process of managing and updating this map.

The effects of secondary task on the control of vehicle under driving simulator: a study among 50s taxi drivers

Han Soo Kim,Jin Seung Choi,Dong Won Kang,Hong Won Yeon,Mi Hyun Choi,Doo Hwan Ji,Byung Chan Min,Soon Cheol Chung,Gye Rae Tack 대한인간공학회 2011 대한인간공학회 학술대회논문집 Vol.2011 No.5

Objective: The aim of this study is to quantitatively evaluate the effects of the secondary task during simulated driving using the variable indicating control of vehicle. Background: There are so many researches for simulated driving and performance. For instance, some researches show that the effects of cell phone conversations on simulated driving. Cell phone conversations impaired explicit recognition memory. Method: Participants included 50s taxi drivers; 15 males and 15 females. All subjects were instructed to keep a distance (30m) from the car ahead and a constant speed (80km/hr or 100km/hr). Sending text message (STM) and Searching navigation (SN) were selected as the secondary task. Experiment consisted of rest for 3min., driving alone for 1min. and driving with secondary task for 1 min.. We were analyzed anterior-posterior coefficient of variation (APCV) and medial-lateral coefficient of variation (MLCV). Results: APCV was increased by 175.4% in STM and 223.8% in SN at 80km/hr. MLCV was increased by 242.3% in STM and 323.4% in SN at 100km/hr. There was no significant difference between genders. Conclusion: Consequently, performing secondary task during driving impaired the control of vehicle.

Differential Effects of Pioglitazone in the Hippocampal CA1 Region Following Transient Forebrain Ischemia in Low- and High-Fat Diet-Fed Gerbils.

Moon, Seung Myung,Choi, Goang-Min,Yoo, Dae Young,Jung, Hyo Young,Yim, Hee Sun,Kim, Dae Won,Hwang, In Koo,Cho, Byung Moon,Chang, In Bok,Cho, Sung-Min,Won, Moo-Ho Kluwer Academic/Plenum Publishers 2015 Neurochem Res Vol.40 No.5

<P>In the present study, we investigated the effects of pioglitazone (PGZ) in the hippocampal CA1 region of low- or high-fat diet (LFD or HFD) fed gerbils after transient forebrain ischemia. After 8 weeks of LFD or HFD feeding, PGZ (30 mg/kg) was intraperitoneally administered to the gerbils, following which ischemia was induced by occlusion of the bilateral common carotid arteries for 5 min. Administration of PGZ significantly reduced the ischemia-induced hyperactivity 1 day after ischemia/reperfusion in both LFD- and HFD-fed gerbils. At 4 days after ischemia/reperfusion, the neurons were significantly reduced and microglial activation was observed in the hippocampal CA1 region in LFD- and HFD-fed gerbils. The microglial activation was more prominent in the HFD-fed gerbils compared to the LFD-fed gerbils. Administration of PGZ ameliorated ischemia-induced neuronal death and microglial activation in the hippocampal CA1 region 4 days after ischemia/reperfusion in the LFD-fed gerbils, but not in the HFD-gerbils. At 6 h after ischemia/reperfusion, tumor necrosis factor-α (TNF-α) and interlukin-1β (IL-1β) levels were significantly increased in the hippocampal homogenates of LFD-fed group compared to control group, and HFD feeding further increased TNF-α and IL-1β levels. PGZ treatment significantly ameliorated the increase of TNF-α and IL-1β levels in LFD-fed gerbils, not in the HFD-fed gerbils. At 12 h after ischemia/reperfusion, superoxide dismutase (SOD) and malondialdehyde (MDA) levels in hippocampal homogenates were significantly increased in the LFD-fed group compared to the control group, and HFD feeding significantly showed relatively reduction in SOD activity and increase in MDA level. PGZ administration significantly reduced the increase in MDA levels 12 h after ischemia/reperfusion in the LFD-fed gerbils, but not in the HFD-fed gerbils. These results suggest that PGZ ameliorates the neuronal damage induced by ischemia by maintaining the TNF-α, IL-1β, SOD and MDA levels in LFD-fed gerbils. In addition, HFD feeding affects the modulation of these parameters in the hippocampus after transient forebrain ischemia.</P>

Improvement and Application for Environmental Conservation Value Assessment Map (ECVAM) of Nationwide Land in Korea

Moung Jin Lee,Seong Woo Jeon,Min Jeong Jo,Won Kyong Song,Byung Jin Kang 大韓遠隔探査學會 2007 大韓遠隔探査學會誌 Vol.23 No.5

This study is aiming at improving the Environmental Conservation Value Assessment Map (ECVAM) of National Land in Korea. The ECVAM items are composed of legal and environmental/ecological assessments. A popular method applied to ECVAM is an overlay environmental/ecological assessment items. The purpose of this study is to offer complementary items of the ECVAM by examining assessment items. In this study we assessed the ECVAM by five methods. Method 1 is Grade 1 areas of each administrative district; Method 2 is comparing overlapped areas of each assessment items Grade 1, 2 and permission of each assessment items duplication; Method 3 is Grade 1, 2 areas by only singular assessment items; Method 4 is Grade 1 areas only of Method 2; and Method 5 is Grade 2 areas only of Method 2. Method 1 showed Seoul and other metropolitan cities revealed a large proportion of Grade I regions by the legal assessment items. Gang won-Do, showed a large proportion of Grade I regions by the environmental/ecological assessment item. Method 2 showed 93.4 % of diameter Grade II (standard for stability); forest diameter item accounted for 99.9 % by Method 3, Method 4 showed 95.7 % of forest diameter, and forest density accounted for 66.4 % by Method 5. This study contributes to reduce the complexity in the process of manufacturing ECVAM of National Land, and to raise the flexibility in the process of managing and updating this map.

재사용이 가능한 나노복합재료 Fe₃O₄-ACCS-Ag의 제조 및 항균 특성 평가

심재홍,김해원,김진원,서영석,오세강,조민,박정희,오병택,Shim, Jaehong,Kim, Hea-Won,Kim, Jin-Won,Seo, Young-Seok,Oh, Sae-Gang,Cho, Min,Park, Junghee,Oh, Byung-Taek 한국지하수토양환경학회 2015 지하수토양환경 Vol.20 No.3

In this study, Fe₃O₄-ACCS-Ag nanoparticles (NPs) were successfully synthesized using silica extracted from corn cob ash. The synthesized Fe₃O₄-ACCS-Ag NPs were characterized using X-ray diffraction (XRD), scanning electron microscopyenergy dispersive X-ray spectroscopy (SEM-EDX), transmission electron microscopy (TEM) and fourier transform infrared spectroscopy (FTIR). In addition, the potential application of Fe₃O₄-ACCS-Ag NPs as an antibacterial material in water disinfection was investigated using Escherichia coli ATCC 8739 as model bacteria. The antibacterial activity of synthesized composite material showed 99.9% antibacterial effect within 20 min for the tested bacteria. From this experiment, the synthesized Fe₃O₄-ACCS-Ag nanocomposites also hold magnetic properties and could be easily recovered from the water solution for its reuse. The reused nanocomposites presented the decreasing antibacterial efficiencies with the reuse cycle but the composite used three times still killed 90% of bacteria in 20 min.

In Vitro Development of Mouse Parthenogenetic Embryos: Effect of Temperature before Oocyte Activation

Roh Sangho,Won Cheolhee,Min Byung-Moo 한국동물생명공학회(구 한국동물번식학회) 2005 Reproductive & Developmental Biology(Supplement) Vol.29 No.2s

This study was conducted to establish the optimal temperature condition before oocyte activation in B6D2 F1 mouse. In experiment 1, two embryo culture media (CZB vs KSOM) were evaluated for the development of activated mouse oocytes. Parthenogenetic embryos cultured in KSOM showed better blastocyst development than ones cultured in CZB(56.2% vs 81.0%, p<0.01). Two-hour of pre-incubation before activation significantly reduced the number of hatched blastocysts in KSOM (22.0% versus 8.8%, p<0.05). In experiment 2, recovered oocytes were pre-incubated at different temperature conditions before activation. The experimental groups were divided by 5 as follows. Group A: pre-incubation for 120 min at 37℃, Group B: pre-incubation at 37℃ for 90 min then at 25℃ for 30 min, Group C: pre-incubation at 37℃ for 60 min then at 25℃ for 60 min, Group D: pre-incubation at 37℃ for 30 min then at 25℃ for 90 min, and Group E: pre-incubation at 25℃ for 120 min before activation. Group A (67.6%) and B (66.7%) showed better development to the blastocyst stage than other groups (Group C: 50.0%, Group D: 49.2%, Group E: 33.3%, p<0.05). The present study indicates that the temperature before activation affects the development of B6D2 F1 mouse parthenogenetic oocytes and exposure to room temperature should be limited to 30-min when the oocytes are left in HEPES-buffered medium for micromanipulation.

P011 Antioxidant functions of kinetin on damage keratinocytes by hydrogen peroxide

( Min Seok Hur ),( Hye In Cheon ),( Byung Gon Choi ),( Song Hee Han ),( Min Jung Kim ),( Hae Jeong Youn ),( Soo Young Kim ),( Nam Kyung Roh ),( Yang Won Lee ),( Yong Beom Choe ),( Kyu Joong Ahn ) 대한피부과학회 2016 대한피부과학회 학술발표대회집 Vol.68 No.2

<div style="display:none">fiogf49gjkf0d</div><div style="display:none">fiogf49gjkf0d</div><div style="display:none">fiogf49gjkf0d</div><div style="display:none">fiogf49gjkf0d</div><div style="display:none">fiogf49gjkf0d</div><div style="display:none">fiogf49gjkf0d</div><div style="display:none">fiogf49gjkf0d</div> Background: Hydrogen peroxide (H2O2) is a species of reactive oxygen, affects to fate of cells in growth, senescence, and extinction. H2O2 is unstable property because of free radicals. As unstable property, H2O2 reacts strong with other molecules and damage to cells and DNA. Kinetin, plant cytokinins, regulates plant growth. It has been reported that kinetin has antioxidant effects, synthesis promotion of DNA, and senescence delay on dermal fibroblast in cellular function. But there is no study reported in effects of kinetin on keratinocytes. Objectives: This study aimed to verify functions of kinetin as a raw material for cosmetics products in skin through the cell efficacy test. Methods: To verify the efficacy of kinetin on HaCaT human keratinocyte cells, the cell viability essay, and reactive oxygen species (ROS) assay were performed. As kinetin with concentrations of 200 μM and above were toxic in HaCaT cells, this study used kinetin with concentrations of less than 200 μM. Results: Cell viability assay showed that kinetin efficiently rescued HaCaT cells from H2O2-induced oxidative stress damages in a concentration-dependent manner. Furthermore, flow cytometry analysis revealed that kinetin decreased the intracellular ROS levels in H2O2-treated HaCaT cells. Conclusion: These data indicated that kinetin can be used as a raw effective natual material for for functional cosmetic products which can reduce facial wrinkles, came from ROS, and improve the condition and function of skin.

Improvement of the Personalized Mobile U-Health Service System

Byung-Won Min 보안공학연구지원센터 2012 International Journal of Multimedia and Ubiquitous Vol.7 No.1

Two cases of actinic cheilitis treated with ingenol mebutate gel

( Byung Gon Choi ),( Min Seok Hur ),( Hye In Cheon ),( Song Hee Han ),( Hae Jeong Youn ),( Min Jung Kim ),( Nam Kyung Roh ),( Soo Young Kim ),( Yang Won Lee ),( Yong Beom Choe ),( Kyu Joong Ahn ) 대한피부과학회 2016 대한피부과학회 학술발표대회집 Vol.68 No.1

Actinic cheilitis (AC) is considered as a precancerous disease that has potential to progress to invasive squamous cell carcinoma. Its treatment, therefore, should be radical, but the optimal therapy is not well established. Ingenol mebutate is a new topical drug extracted from plant Euphorbia peplus, which was approved by the US Food and Drug Administration for field therapy of actinic keratosis (AK) in 2012. Although it was approved for treatment of AK there are attempts of applying it on other lesions such as Bowen’s disease, squamous cell carcinoma and basal cell carcinoma. There is only one case report, however, of AC treatment with ingenol mebutate in Spain, and no report in Korean literature. We applied ingenol mebutate 0.015% gel to two 65-year-old patients (one is female and the other is male) diagnosed with AC by punch biopsy. We made a barrier surrounding the accurate lesion by antimicrobial ointment and conducted spot therapy for reducing local skin reaction (LSR) and drug inflow into intraoral cavity. Eight weeks after the treatment, the size of lesions was much decreased in both patients. The female patient showed almost complete clearance, and less than 50% of lesions remained of the male patient. Erosion, discharge and mild pain were accompanied as LSR, and resolved in 2 weeks. We report our experience and suggest that ingenol mebutate 0.015% gel could be an effective and safe treatment option for AC.