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.

構造 安定度에 관한 歷史的 고찰

申鍾學,李 皓 慶一大學校 1987 論文集 Vol.3 No.1

History is briefly reviewed to gain a perspective of our present standards for structural safety. some outstanding structures, development of engineering, and instances of safety regulations are cited. The panorama of events illustrates a wealth of experiences in the development of the factor of safety.

朴木月 初期詩에 나타난 美的 距離의 樣相

신종호 崇實語文學會 2000 崇實語文 Vol.16 No.-

디스크형 캠기구 설계를 위한 순간속도중심설계법의 연구

신중호,김종수 國立 昌原大學校 産業技術硏究所 1994 産技硏論文集 Vol.8 No.-

As direct contact mechanisms, cam and follower mechanisms are used commonly in many machinery. Disk-typed cam mechanisms have 4 different types due to the different type of followers, such as reciprocating roller type, reciprocating flat-face type, oscillating roller type, and oscillating flat-face type. Depending on the shape of cam and type of follower, the motion of cam-follower mechanism is determined. Thus design procedure must be well defined for determining acculately the shape of cam corresponding to the given motion of follower. In this paper, an instant velocity center method is proposed. This method calculates the instant velocity centers of cam and follower in contact motion at any time. From geometric relationships on contact points of cam with follower, cam shape can be determined using the instant velocity centers. Also this paper presents 4 different cams for demonstration of the proposed design method and the results gives the exact solutions of cam design.

Streptomyces 속 균주 HA-40이 생산하는 내열성 α-Amylase의 효소학적 성질

신운섭,이동희,이현우,권태종,정호권 建國大學校 附設 産業技術硏究所 1988 논문집 Vol.13 No.-

토양으로부터 분리한 Streptomyces 속 균주 HA-40이 생산하는 내열성 α-amylase의 효소학적 성질을 조사한 결과는 다음과 같다. 효소의 작용 최적 온도는 65℃였으며 activation energy 는 16.9Kcal/mole이었고 60℃에서는 안정하였으나 70℃에서는 30분 처리로 약 50%, 1시간 처리로 약 75%가 실활하였다. 그러나 ??를 0.1mM농도로 첨가한 경우엔 70℃ 에서 1시간 처리하여도 잔존활성도가 55%이상으로 열변성에 대한 ??의 보호효과가 있었다. 본 효소는 pH7에서 활성이 가장 강하였으며 안정성도 가장 높았다. 그리고 금속이온 중에서 ??의 첨가로 효소활성이 증대되었으며 ??, ??, ??등에 의해서 활성이 저해되었다. 각종 효소저해제는 대부분 영향을 미치지 못하였으나 EDTA가 반응액 중에 공존하면 효소활성이 강하게 저해되었다 본 효소는 maltotriose이하의 당류에 대해서는 분해력이 없었으며 amylose에 대한 환원당 생성력을 100으로 하였을때 soluble starch 108, amylopectin 94, glycogen 87, dextrin 48, potato starch 25, corn starch 18로 생전분에 대한 분해력은 soluble starch에 비해서 1/4∼1/5 정도밖에 되지 않았다. 그리고 soluble starch에 대한 Km 치는 1.9㎎/㎖였다. The properties of a thermostale α-amylase produced from Streptomyces sp. strain HA-40, isolated from soil, were investigated. The optimal temperature of the enzyme was 65℃ and the enzyme was stable below 60℃. However, at 70℃ about 75% of the activity was lost after 1hr treatment, but by the addition of ?? in the concentration of 0.1mM only 45% of the activity was lost. The enzyme was most active and stable at around pH 7. The activity of the enzyme was increased by the addition of ??, but depressed by ??, ??, and EDTA. The enzyme could be hydrolyze soluble starch, amylose, amylopectin and glycogen well, and could also digest dextrin and raw starch. The Km value for soluble starch was 1.9㎎/㎖.

苛性소다 處理에 依한 밀짚의 飼料價値 增進 硏究

辛炯泰,金贊昊,金鍾奭,宋永祿,林泰鎭 成均館大學校 1982 論文集 Vol.32 No.-

Nylon bag dry matter digestibility (NBDMD, %), nylon bag organic matter digestibility (NBOMD, %) and chemical compositions were analysed to evaluate the nutritive values of 5 varieties of NaOH-treated wheat straws (Jangkwang, Wonkwang, Suwon 210, Suwon 211, Naemil) by using Korean native male goats. Three grams of dried samples by grinding with 2.45㎜ Wiley mill screen were put into a bag 9×14㎠ made of 100 mesh nylon. These bags were put into the ventral sac of the rumen and taken out at the end of 72 hours. They were washed, dried in an oven at 105℃ for 24 hours and weighed “NBDMD” (%) and ashed in an muffle furnace at 600℃ or 24 hours and weighed “NBOMD”(%). The results which were obtained with this experiment were as follows: 1. Nylon bag dry matter digestibility (NBDMD, %) and nylon bag organic matter digestibility (NBOMD, %) of NaOH-treated wheat straws were highly significant different (p<0.01) in different levels of NaOH treatment and of different varieties of wheat straws. 2. The relationship between total mean NBDMD (%, Y_1) of 5 varieties of wheat straws and NaOH concentration (%, X) at 72 hours rumen incubation was: Y_1=34.57+3.56X(r=0.92^**) 3. The relationship between total mean MBOMD (%, Y_2) of 5 varieties of wheat straws and NaOH concentration (%, X) at 72 hours rumen incubation was: Y_2=32.02+2.46X(r=0.92^**) 4. The orders of NBDMD(%) and NBOMD(%) for 5 varieties of wheat straws were Suwon 210, Suwon 211, Naemil, Jangkwang, Wonkwang and Suwon 211, Suwon 210, Naemil, Jangkwang, Wonkwang, respectively. 5. The optimum level of NaOH for improving NBDMD(%) from 5 varieties of wheat straws, on the basis of Blaxter et al. (1961), was 6% NaOH.

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".

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.