Effects of Test Temperature on Low Cycle Fatigue Behaviors in Large Mold Steel

Jong‑Ho Shin,Jehyun Lee 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7

A mold steel for plastic injection was subjected to low cycle fatigue (LCF) tests at temperatures of 25, 200, and 250 °C. LCFtests were carried out at a total strain amplitude (Δεt/2) from 0.004 to 0.012 under a constant strain rate of 0.01 s–1. Transmissionelectron microscope images showed that cyclic loading accelerated dislocation recovery as the LCF test temperatureincreased. The LCF life increased as a result of improvement in the ductility associated with dislocation recovery as the testtemperature increased. The LCF behavior at the test temperature range followed the Coffin–Manson equation. Empiricalequation was proposed to predict the LCF life of the mold steel within the test temperature range.

Modified Microstructure Selection Map and Growth Conditions of the Band Structure in Directionally Solidified Hypo-Peritectic Alloys

Jong‑Ho Shin,Jehyun Lee 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.5

Considering the variation of the solid/liquid interface morphology with a growth condition, microstructure selection map inperitectic system was modified by comparing growing α (primary phase) interface tip temperature and β (peritectic phase)nucleation temperature. The results were proved experimentally in hypo-peritectic Sn–Cd alloys by delicate directionalsolidification experiment under the diffusive growth condition using capillary thin tube. When β-phase took over α-phaseand grew a short distance as the leading phase, the instability of β-phase was first observed experimentally. This phenomenawas explained by constitutional undercooling, which was present temporarily in liquid ahead of the β/l interface.

Nrf2-Heme oxygenase-1 modulates autophagy and inhibits apoptosis triggered by elevated glucose levels in renal tubule cells

Joo Heon Kim,김경민,Jin Uk Jeong,Jong-Ho Shin,신재민,방기태 대한신장학회 2019 Kidney Research and Clinical Practice Vol.38 No.3

Background: Autophagy is a highly balanced process in which lysosomes remove aged and damaged organelles and cellular proteins. Autophagy is essential to maintain homeostasis in the kidneys. Methods: Using human renal tubule cells HK-2, we assessed the impact of high glucose (HG) on autophagy. We also evaluated the capability of sulforaphane (SFN) to protect the HK-2 cells from HG-induced apoptosis by modulating autophagy. Results: SFN modulated autophagy and decreased apoptosis in the HK-2 cells that were cultured in 250 mM glucose medium for two days. The reactive oxygen species (ROS) levels increased, as expected, in the cells cultured in the 250 mM glucose medium. However, the SFN decreased the ROS levels in the HK-2 cells. The overexpression of heme oxygenase-1 (HO-1) by SFN decreased the expression of LC3 and beclin-1. LC3 and beclin-1 were involved in the downregulation of caspase-3 that was observed in the HG-induced cells. Conclusion: The activation of nuclear factor E2-related factor 2 (Nrf2)-HO-1 inhibited ROS expression and subsequently attenuated autophagy and cell apoptosis after HG injury was decreased. HG injury led to the activation of autophagy and HO-1 in order to combat oxidative stress and protect against cell apoptosis. Therefore, HO-1 activation can prevent ROS development and oxidative stress during HG injury, which considerably decreases autophagy and apoptosis.

몰리브덴이 첨가된 Stellite 6 합금의 마모와 부식특성

申種喆,金在洙,李德悅,梁在雄,尹珍國,盧大虎,李種權 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.10

Hardfacing layers of Stellite 6 with different molybdenum content are deposited on AISI 1045-carbon steel using Plasma Transferred Arc welding(PTA) machine. The microstructures, wear and corrosion resistances of the hardfacing layer are investigated in order to clarify the effect of molybdenum in Stellite 6 alloys. The microstructural characterizations of the hardfacing layers are performed using X-ray diffraction, back scattered electron images, and scanning electron microscopy. With an increase of Mo contents, M_6C type carbide are formed instead of Cr-rich type carbides, and so this microstructural change enhanced the mechanical properties such as wear and corrosion resistance of a Mo-modified Stellite 6 alloy.

LCA 기법을 적용할 제품의 우선순위 선정 방법론

신동희,권은선,문승식,김만영,정종연,허진호 한국전과정평가학회 2004 한국전과정평가학회지 Vol.5 No.1

본 연구의 목적은 일정한 논리적 절차를 거쳐서 객관적인 전과정평가의 우선순위를 선정하기 위한 일반적인 방법론의 개발이다. 우선 전과정평가 대상이 되는 제품(산업군)의 우선순위를 평가하기 위해서 제품의 환경성과 관련된 환경규제, 국내외 전과정평가 수행사례, 유해물질 등을 평가항목으로 설정하였다. 설정된 평가항목들에 대한 자료조사 및 분석을 통하여 세분화한 데이터베이스를 생성하였으며, 또한 학계 및 산업계의 의견을 반영하기 위해 전과정평가 전문가 및 산업계 관계자들을 대상으로 설문조사를 실시하였다. 설문조사결과를 바탕으로 각각의 평가항목 및 세부평가항목의 가중치를 부여하였고, 각 평가항목별로 점수를 설정하였다. 본 연구에서 개발한 방법론은 우선순위를 비교해야하는 제품(산업군)들이 각각의 평가항목에서 설정해놓은 해당 점수를 부여받게 된다. 부여받은 각 평가항목의 점수들을 모두 합산하면 평가대상이 되는 제품(산업군)에 대해 하나의 우선순위 평가 점수를 갖게 된다. 이와 같은 과정으로 방법론이 구축되었으며, 사례연구를 통하여 방법론의 타당성을 검증하였다. 이렇게 산출된 우선순위 평가점수를 평가하고자하는 제품(산업군)들과 비교하여 높은 점수를 갖는 제품(산업군)이 전과정평가를 먼저 실시하는 것이 바람직하다는 결론을 얻을 수 있다. The purpose of this study is to develop a general method to decide the priority of LCA application through a logical procedure. First of all, evaluation categories were developed to decide priority of subject products(industrial groups). The evaluation categories consist of environment regulations related to subject product, LCA case studies, hazardous substances, etc. The subdivided database was constructed through researching and analyzing information about the selected evaluation categories. In addition, a questionnaire was conducted to reflect the opinions from academic and industrial circles. Based on the result of the questionnaire, each evaluation category and sub-evaluation category were weighed differently, and certain points were assigned to them. According to the method developed in this study, comparing industrial groups or products for prioriting will have its total score that is a sum of points assigned to each evaluation category. This results that an industrial group or product having higher score than the others becomes the subject to apply LCA.

말 기생충성 동맥염 2예

신태균,김승호,배종희,이두식,임윤규,이수길 濟州大學校 農科大學 動物科學硏究所 1992 動物科學論叢 Vol.7 No.1

Two cases of verminous arteritis were chosen for this case. These horses were originally submitted for necropsy in the Cheju horse race. Case 1 : At necropy, there was increased ascite, thickened ab-dominal aorta at junction of cranial mesenteric artery. In the aorta, there was a long thrombus embed-ded with strongylus vulgaris larvae. Some larvae were also firmly attached in the aortic intima Histologically, there was infiltration of neutropliils, eosinophils, and macrophages in the tunica media. At the junction of thrombus and arterial intima, there was proliferation of vessels. Case 2 : At necropsy, there was thickened abdominal aorta, which showed typical verminous arteritis with thrombus. Histologically, ceseous tissues with haematopoietic tissue was recognized in the aortic wall.

중부지역 옥수수 파종기에 따른 생육단계 및 수량성 변화

서종호, 문중경, 정건호, 서민정, 구자환, 박장환, 배환희, 신성휴, 권영업 忠北大學校 農業科學硏究所 2014 農業科學硏究 Vol.30 No.2

Maize hybrids were planted on April 1, April 25, May 20 and June 15 in 2012, 2013 at the experimental paddy and upland fields in Suwon city , respectively to know changes of growth stage and yield according to different planting time. Maize planting on April 1 was not recommended because total growing days at planting on April 1 was not different with that at planting on April 25 due to many days from planting to emergence over 20 days at planting on April 1. Total growing days were not much different among three planting time after April 25 because days from silking to maturity was lengthened though days from planting to silking was shortened at later planting time. Stalk weight was decreased as planting time was delayed, particularly at planting times after May 20 at paddy field by excess water injury during early growth stage. But, grain yield was not low as in May and June. It is needed to introduce early maturity maize variety as Yanganok at late planting for higher grain yield and enough time for soil preparation for next winter crops

성인 양극성장애와 정신분열병 환자의 아동기 주의력결핍 : 과다활동 증상

신정호,안정숙,이계성 대한소아ㆍ청소년정신의학회 1998 소아청소년정신의학 Vol.9 No.1

濟州道公務員의 特性과 庶政刷新에 관한 硏究

申宗淳,鄭允武,朴瑾浩,金武昌 동국대학교 행정대학원 1977 행정논집 Vol.7 No.-

후진타오체제 중국 경제외교와 대외전략적 함의

신종호 한국외국어대학교 외국학종합연구센터 중국연구소 2006 中國硏究 Vol.37 No.-

‘Economic diplomacy' as a pattern of diplomacy is an important feature of foreign policy of the Hu Jintao's era in china. Economic diplomacy refers to diplomatic policy and behavior which are implemented by sovereign state and its representative organizations or personnel for realizing economic goal or non-economic goals by economic means. China, the World’s second- biggest crude oil buyer, has been seeking to secure stable energy supplies to reduce its vulnerability to global oil price fluctuations. Chinese leader's effort to enforce Economic diplomacy has made some achievements, such as improving China's international status and influence, supporting China's “Going-out" strategy, and isolating taiwan from international community, etc. However, Chinese leader's immoderate cling onto the energy security will bring about the strategic contradiction with the U.S in Africa, Latin America and Central Asia. In addition, It might cause negative effect on their efforts, such as emphasizing “Peaceful Rising" and “Peaceful development", shaping “Responsible Great Power" image, and preventing the proliferation of "Chinese Threats".