분사주조법에 의한 저열팽창 알루미늄합금의 제조

박종성,이정근,김명호 ( Chong Sung Park,Jeong Keun Lee,Myung Ho Kim ) 한국주조공학회 1997 한국주조공학회지 Vol.17 No.3

N/A In order to fabricate lower thermal expansion aluminium alloys, the effects of microstructural parameters such as the volume fraction of SiC_p and the shape and size of Si phase on the coefficient of thermal expansion(CTE) of the spray-cast and hot-extruded hypereutectic Al-Si(A390) alloy composites were investigated experimentally. The CTEs of hypereutectic Al-Si (A390) alloy were changed proportionally with the size of Si phase. Ultimate tensile strength, elongation and Young`s modulus of the spray-cast and hot-extruded specimen were improved dramatically compared to those of the permanent mold-cast specimen. Although Young s modulus of the spray-cast and hot-extruded specimen was improved highly effectively by addition of SiC_p, no improvement was observed for the UTS and elongation. Spray-cast and hot-extruded hypereutectic Al-Si (A390) alloy reinforced with 20vol.%SiC_p exhibits a CTE equivalent to stainless steel.

과공정 Al-Si 합금의 열팽창거동과 기계적 성질에 미치는 미세조직의 영향

박종성,이정근,김명호 ( Chong Sung Park,Jeong Keun Lee,Myung Ho Kim ) 한국주조공학회 1997 한국주조공학회지 Vol.17 No.4

N/A The egects of changes in microstructure of Si phase on the thermal expansion coefficients(CTEs) and tensile properties of the hypereutectic Al-Si foundry alloy(A390) were investigated experimentally. Specimens were prepared by various fabrication processes, such as a permanent mold casting, a squeeze casting and a spray casting process, and subsequently hot-extruded. CTEs of the spray-cast specimen were found to be about 10% lower than those of the permanent mold-cast specimen, and the CTEs of the hypereutectic Al-Si alloy(A390) were changed proportionally with the size of Si phase. Ultimate tensile strength of the spray-cast and hot-extruded specimen was dramatically improved about 100% with improved elongation, compared to that of permanent mold-cast specimen. These improvements are mainly attributed to the reduction in size and aspect ratio of the brittle Si phase, and the elimination of the microvoids/porosities formed during casting.

초음파 주파수 및 반응조건 변화에 따른 나프탈렌 분해효율과 OH 라디칼의 발생량 비교

박종성(Jong Sung Park),박소영(So Young Park),오재일(Jei Ll Oh),정상조(Sang Jo Jeong),이민주(Min Ju Lee),허남국(Nam Guk Her) 大韓環境工學會 2009 대한환경공학회지 Vol.31 No.2

나프탈렌은 휘발성이 있는 소수성 물질로 발암유발 가능성이 있고, 수생태계에 심각한 영향을 미친다. 본 연구는 초음파의 주파수 및 반응조건별 나프탈렌 분해효율과 OH 라디칼 변화량을 조사하였다. C-18 역상칼럼을 이용한 LC/FLD (1200 series, Agilent)로 나프탈렌을 분석한 결과 MDL (Method detection limit)은 0.01 ppm이었다. 초음파 조사 동안 휘발된 나프탈렌은 거의 검출되지 않았고(0.05 ppm 이하), 반응조 덮개 개폐별 나프탈렌 분해효율은 거의 차이를 보이지 않았다(1% 이내). 초음파 반응온도가 증가할수록 나프탈렌 제거효율은 감소하는 경향(15℃: 95%→40℃: 85%)을 보였고, pH가 낮을수록 나프탈렌 분해효율이 증가(pH 12: 84%→pH 3: 95.6%)하였다. 나프탈렌 초기농도의 감소에 따라 반응속도는 증가하는 경향을 보여주었다(2.5 ppm: 27.3×10(-3) min(-1), 5 ppm: 22.7×10(-3) min(-1), 10 ppm: 19.0×10(-3) min(-1)). 동일한 초음파 조건(2.5 ppm 나프탈렌, 0.075 W/mL, 20℃, pH 6.8)에서 28 kHz의 분해효율이 132 kHz보다 약 1.46배 높았고(132 kHz: 56%, 28 kHz: 82.7%), 유사 일차반응 속도상수(k1)도 약 2.3배 높게 나타났다(132 kHz: 2.4×10(-3) min(-1), 28 kHz: 5.0×10(-3) min(-1)). 초음파 조사 10분 후 H₂O₂ 농도는 132 kHz가 28 kHz보다 약 7.2배 높았지만(132 kHz: 0.36 ppm, 28 kHz: 0.05 ppm), 조사 90분 후에는 28 kHz가 132 kHz보다 1.1배 높았다(28 kHz: 0.45 ppm, 132 kHz: 0.4 ppm). 2.5 ppm 나프탈렌 용액에 132 kHz와 28 kHz 초음파 조사시 발생된 H₂O₂ 농도는 초순수에 초음파 조사한 결과보다 각각 0.1 ppm과 0.05 ppm씩 낮게 나타났다. 혼형(24 kHz)과 배스형(28 kHz) 초음파의 나프탈렌 분해효율은 각각 87%와 82.7%였고, k1은 22.8×10(-3) min(-1)와 18.7×10(-3) min(-1)로 산출되었다. 다주파 복합형 초음파 시스템(28 kHz 배스형+24 kHz 혼형 초음파)의 나프탈렌 분해효율은 단일주파수 24 kHz(혼형)와 비슷한 제거효율을 보였으나(88%), H₂O₂의 농도는 약 3.5배 높게 조사되었다(28 kHz+24 kHz: 2.37 ppm, 24 kHz: 0.7 ppm). 이와 같은 다주파 복합형 초음파 시스템은 OH 라디칼에 의해 산화가 잘 일어나는 물질의 분해에 매우 효과적으로 적용될 수 있을 것으로 예상된다. Naphthalene is a volatile, hydrophobic, and possibly carcinogenic compound that is known to have a severe detrimental effect to aquatic ecosystem. Our research examined the effects of various operating conditions (temperature, pH, initial concentration, and frequency and type of ultrasound) on the sonochemical degradation of naphthalene and OH radical production. The MDL (Method detection limit) determined by LC/FLD (1200 series, Agilient) using C-18 reversed column is measured up to 0.01 ppm. Naphthalene vapor produced from ultrasound irradiation was detected under 0.05 ppm. Comparison of naphthalene sonodegradion efficiency tested under open and closed reactor cover fell within less than 1% of difference. Increasing the reaction temperature from 15℃ to 40℃ resulted in reduction of naphthalene degradation efficiency (15℃: 95%→40℃: 85%), and altering pH from 12 to 3 increased the effect (pH 12: 84%→pH 3: 95.6%). Pseudo first-order constants (k1) of sonodegradation of naphthalene decreased as initial concentration of naphthalene increased (2.5 ppm: 27.3×10(-3) min(-3)→10 ppm : 19.0×10(-3) min(-3)). Degradation efficiency of 2.5 ppm of naphthalene subjected to 28 kHz of ultrasonic irradiation was found to be 1.46 times as much as when exposed under 132 kHz (132 kHz: 56%, 28 kHz: 82.7%). Additionally, its k1 constant was increased by 2.3 times (132 kHz: 2.4×10(-3) min(-1), 28 kHz: 5.0×10(-3) min(-1)). H₂O₂ concentration measured 10 minutes after the exposure to 132 kHz of ultrasound, when compared with the measurement under frequency of 28 kHz, was 7.2 times as much. The concentration measured after 90 minutes, however, showed the difference of only 10%. (concentration of H₂O₂ under 28 kHz being 1.1 times greater than that under 132 kHz.) The H₂O₂ concentration resulting from 2.5 ppm naphthalene after 90 minutes of sonication at 24 kHz and 132 kHz were lower by 0.05 and 0.1 ppm, respectively, than the concentration measured from the irradiated M.Q. water (no naphthalene added.) Degradation efficiency of horn type (24 kHz) and bath type (28 kHz) ultrasound was found to be 87% and 82.7%, respectively, and k1 was calculated into 22.8×10(-3) min(-1) and 18.7×10(-3) min(-1), respectively. Using the multi- frequency and mixed type of ultrasound system (28 kHz bath type+24 kHz horn type) simultaneously resulted in combined efficiency of 88.1%, while H₂O₂ concentration increased 3.5 times (28 kHz+24 kHz: 2.37 ppm, 24 kHz: 0.7 ppm.) Therefore, the multi-frequency and mixed type of ultrasound system procedure might be most effectively used for removing the substances that are easily oxidized by the OH radical.

FAB 분류에 의한 급성백혈병

박종성 ( Jong Sung Park ),이정국 ( Jeong Koog Lee ),김홍범 ( Hong Bum Kim ),태명산 ( Myung San Tae ),조성락 ( Sung Rak Joe ),나하연 ( Ha Yeon Rha ),이은엽 ( Eun Yup Lee ) 대한내과학회 1982 대한내과학회지 Vol.25 No.7

4차 산업혁명시대, 품질경쟁력을 잡아라! - 현대자동차 사례를 중심으로 -

박정현 ( Park Jeong Hyun ),박종성 ( Park Jong Sung ),박종엽 ( Park Jong Yup ),석지원 ( Suk Ji Won ),편정희 ( Pyeon Jeong Hee ) 한국품질경영학회 2018 한국품질경영학회 학술대회 Vol.2018 No.-

Effects of Epigallocatechin-3-Gallate on the Expression of TGF-β1, PKC α/βII, and NF-κB in High-Glucose-Stimulated Glomerular Epithelial Cells

Sung Jun Park,Ji Min Jeong,정한성,박종성,김남호 전남대학교 의과학연구소 2011 전남의대학술지 Vol.47 No.2

Epigallocatechin-3-gallate (EGCG) is the most potent antioxidant polyphenol in green tea. In the present study, we investigated whether EGCG plays a role in the expression of transforming growth factor-beta1 (TGF-β1), protein kinase C (PKC) α/βII, and nuclear factor-kappaB (NF-κB) in glomerular epithelial cells (GECs) against high-glucose injury. Treatment with high glucose (30 mM) increased reactive oxygen species (ROS)/lipid peroxidation (LPO) and decreased glutathione (GSH) in GECs. Pretreatment with 100 μM EGCG attenuated the increase in ROS/LPO and restored the levels of GSH,whereas ROS, LPO, and GSH levels were not affected by treatment with 30 mM mannitol as an osmotic control. Interestingly, high-glucose treatment affected 3 separate signal transduction pathways in GECs. It increased the expression of TGF-β1, PKC α/βII, and NF-κB in GECs, respectively. EGCG (1, 10, 100 μM) pretreatment significantly decreased the expression of TGF-β1 induced by high glucose in a dose-dependent manner. In addition, EGCG (100 μM) inhibited the phosphorylation of PKC α/βII caused by glucose at 30 mM. Moreover, EGCG (1, 10, 100 μM) pretreatment significantly decreased the transcriptional activity of NF-κB induced by high glucose in a dose-dependent manner. These data suggest that EGCG could be a useful factor in modulating the injury to GECs caused by high glucose.

기계분야 직무체계 개발과 국가기술자격종목 연계실태 분석 연구

박종성(Jong-Sung Park),조정윤(Jeong-Yoon Cho) 한국공학교육학회 2010 공학교육연구 Vol.13 No.4

이 연구는 기계분야 직무체계 개발과 국가기술자격종목 연계실태 분석에 목적이 있다. 문헌연구, 면담조사, 전문가협의회를 통해 산업현장에서 통용되는 용어를 중심으로 직무를 분류하고 직무수준을 설정하였다. 직무분류 결과 기계분야의 직무군은 크게 중분류 3개, 소분류 11개, 이들 소분류를 다시 분류하면 총 42개의 직무가 도출되었다. 기계분야의 직무수준은 국가자격 체제(KQF)의 수준체계와 자격 및 교육과정, 산업 현장의 직무별 수준을 반영하여 7단계로 구분하였다. 도출된 직무 체계를 바탕으로 직무군과 직무 정의를 제시하였으며, 각 직무별 정의와 직무별· 수준별 수행기준을 도출하였다. 또한 개발된 직무체계와 국가기술자격 종목과의 연계실태를 분석하여 자격종목 개선방안을 제시하였다. The goal of this study is an analysis on linkage system between in machinery sector. The development of skill framework and national technical qualification items. This paper researched skills and created the skill level through reviewing domestic & foreign documents, interview with experts and in-depth discussions with expert group focusing on terminologies commonly used in the industrial settings. As a result of skill classification, authors were able to classify skills into three categories in medium-scale classification and 11 categories in small-scale classification, and also into total 42 categories through the re-classification of the small-scale classification. The skill level in the area of machine were classified the skill level in the area of machine into 7 level by reflecting the level system of the korean qualification frameworks, qualification and education course, and skill level in the industrial setting. Based on the skill frameworks, we provided definition of skill and skill group, definition of each different skill, and performance standards by skill and level. also, This paper suggests improving measure of national technical qualification items through analysizing linkage situation between skill frameworks & qualification items

광삼각법을 이용한 레이저 변위 센서의 특성 연구

박종성(Jong Sung Park),정규원(Kyuwon Jeong) Korean Society for Precision Engineering 1999 한국정밀공학회지 Vol.16 No.7

저압주조품의 미세조직과 기계적 성질에 미치는 금형온도의 영향

이정근,박종성,김명호 ( Jeong Keun Lee,Chong Sung Park,Myung Ho Kim ) 한국주조공학회 1998 한국주조공학회지 Vol.18 No.3

N/A Microstructure and mechanical properties of the low pressure die-cast Al wheels were investigated by microscope, image analyzer, NDT (non-destructive test), and tensile test. The variation of SDAS (secondary dendrite arm spacing), porosity per unit area, quality grade, and tensile properties with the mold temperatures were examined. SDAS was gradually decreased with a decrease in temperature. However, the lowest value of porosity per unit area was observed at the mold temperature of 405˚C and the optimum mold temperature was found to be 405˚C. Besides, from the observation of pore morphology, it was also found that the pore formation was mainly caused by shrinkage during solidification. The tensile strength, elongation, and impact toughness were markedly decreased, however the yield strength was nearly constant. The decrease of mechanical properties is attributed to the increase of porosity. (Received January 23, 1998)

지식.정보화시대에 요구되는 국가기술자격 검정방법 도입을 위한 연구 - 기능장, 기사, 산업기사, 기능사를 중심으로 -

조정윤,박종성,김덕기,김현수,Cho Jeong-Yoon,Park Jong-Sung,Kim Deog-Ki,Kim Hyun-Soo 한국공학교육학회 2001 공학교육연구 Vol.4 No.1

이 연구는 지식 정보화 시대에 인적자원을 효과적으로 개발 선도하도록 국가기술자격제도에 있어서 검정방법을 개선하는데 목적이 있다. 이 연구의 목적을 달성하기 위해 국가기술자격 검정방법의 변천내용과 방향의 적합성에 대해서 살펴보았으며, 주요국의 검정방법과 국내 외 컴퓨터화된 검정방법의 적용실태를 분석하였다. 아울러 현재 국가기술자격 기능장, 기사, 산업기사, 기능사 검정방법의 문제점과 검정인프라의 문제점을 알아보았다. 이를 바탕으로 검정방법의 개선 방안과 이를 위한 검정 인프라 구축 방안을 제시하였다. 연구방법으로 관련자료의 수집 및 분석, 4차에 걸친 전문가 협의회 개최, 국가기술자격 검정방법 실태 및 요구분석을 위하여 기능장, 기사, 산업기사, 기능사 자격취득자를 대상으로 2,500명을 대상으로 설문 조사를 실시하여 의견을 수렴하였다. 이상의 연구를 통해 기능장, 기사 산업기사 기능사 검정방법의 개선 방안, 제도적인 면과 운영적인 측면에서의 검정 인프라 구축 방안에 대해서 살펴보았다. Due to developments in information technology and ensuing changes in the concept of time and space, the significance of national boundaries has been weakened, bringing to attention the heightened competition among nations. In order to respond to these transformations, the Korean government is increasing its efforts to raise the authenticity of the National Technology Qualification System(NTQS) by closely linking NTQS testing method and procedure to practical knowledge and skills in the industry field. This initiative is based on the recognition that the human resources development is a crucial factor in determining a nation's competitiveness. This study aimed, first of all, to diagnose the problems directly and indirectly affecting the testing method in the current NTQS. And then, differentiated solutions according to grade and improvements in the testing infrastructure were suggested. The ultimate purpose was to provide a blueprint for enhancing national competitiveness through increased authenticity and efficiency of the NTQS. Research methods applied during this study include: the collection and review of qualification-related literature; a series of conferences with leading experts; interviews with vocational educators and researchers from qualification-related institutes; a survey of national qualification holders from a variety of professions and industries; and participatory observation at qualification exam centers. This research suggested policy recommendations as follows; First, measures to improve for testing method of professional engineer Second, measures to improve for testing method of Master craftsman Third, measures to improve for testing method of Engineer, Industrial Engineer, Craftsman Fourth, plans for the establishment of operation system for a computerized testing Fifth, institutional perspective on establishing qualification infrastructure Sixth, operational perspective on establishing qualification infrastructure