SM53C 탄소강 자동차 부품 곡면부의 고주파 열처리 미세조직 및 경도 변화

이지성,오민철,이세환,전용호,안병민 한국생산제조학회 2018 한국생산제조학회지 Vol.27 No.6

High-frequency induction hardening is one of the most commonly used heat treatment techniques for steel and by which enhanced surface hardness can be achieved for fatigue and wear resistance. During this process, a certain depth of products is rapidly heated and quenched so that the microstructure of the hardened surface is finer than those of the other parts of the product. In general, the hardening depth is more uniform in the straight surface than in the irregular- or complex-shaped surfaces because of the non-uniform heating and cooling rates in the irregular surfaces applied from the induction coils. This non-uniform hardening depth can cause unexpected deterioration of the fatigue properties. In this study, high-frequency induction hardening was applied to an SM53C steel automotive part having a 90° curved shape, and the microstructure and hardness variation in the curvature area were characterized in detail.

불임환자의 난관인자검사에 있어서 자궁난관조영술과 복강경소견의 비교 관찰

이지성,이남용,이원영,송찬호 대한산부인과학회 1985 Obstetrics & Gynecology Science Vol.28 No.9

한국인을 위한 뇌졸중 발생 예측모형 개발

이지성,박종무,박태환,이경복,이수주,조용진,한문구,배희준,이준영 대한신경과학회 2010 대한신경과학회지 Vol.28 No.1

Background: Assessing an individual’s risk of stroke can be a starting point for stroke prevention. The aim of this study was to develop a stroke prediction model that can be applied to the Korean population, using the best available current knowledge. Methods: A sex- and age-specific stroke prediction model that is applicable specifically to Koreans was developed using Gail’s breast cancer prediction model, which is based on competing risk theory. Results: The relative risks for major stroke risk factors, including hypertension, diabetes, hypercholesterolemia, atrial fibrillation, ischemic heart disease, previous stroke, obesity, and smoking status, were obtained from a recent systematic review of stroke risk factors among Koreans. The results were incorporated into the concept of a proportional hazard regression model. For baseline age- and sex-specific hazard rates for stroke, we employed Jee’s 10-year stroke-risk prediction model with its reference categories for predictor variables. Death-certificate data from the Korea National Statistical Office were used to calculate competing risks of stroke in our model. Conclusions: Our prediction model for stroke incidence may be useful for predicting an individual’s risk of stroke based on his/her age, sex, and risk factors. This model will contribute to the development of individualized risk-specific guidelines for the prevention of stroke.

추진공급계 개발품 시험을 위한 수력학 시험 설비 구축

이지성,임하영,김정한,한상엽 한국항공우주학회 2015 한국항공우주학회 학술발표회 논문집 Vol.2015 No.11

발사체의 추진기관을 구성하는 부품의 수력학적 특성을 시험하기 위한 수력학 시험 설비가 구축되었다. 구축된 시험설비는 사용유량 및 압력에 따라 수력학 시험실-1과 2로 나뉜다. 수력학 시험실-1의 경우 최대 5 MPa/180 kg/s 까지 시험 가능하고, 수력학 시험실-2의 경우 최대 30 MPa/40 kg/s 까지 시험가능하다. 수력학 시험실은 물을 채우고 가압해 주는 준비실과 공압밸브 및 레귤레이터를 조작하고 데이터를 저장하는 제어계측실, 실제 시험물이 장착되어 시험이 이루어지는 시험실로 구분되며 최소 2인 이상이 시험설비를 운영할 수 있도록 규정하고 있다. 구축된 수력학 시험 설비는 인증시험을 통해 성능 및 안전성이 확보되었으며, 현재 한국형발사체 주요 구성품의 개발/인증/수락 시험이 진행되고 있다. Hydraulic laboratories (HL) are constructed for the test of propulsion units. The laboratory is devided by two types as HL-1 and HL-2. The testing capacity of HL-1 and HL-2 is up to 5 MPa/180 kg/s and 30 MPa/40 kg/s respectively. Hydraulic loboratory is composed of preparation room for the clean and high pressure water, control room for the valves and regulators, and the laboratory where the test section is located. The test performance and the safety of the test facility are proven with qualification test. Development, qualification, and acceptance tests of newly developed propulsion units are undergoing in the constructed hydraulic laboratories.

‘능력주의’사회에 대한 기독교사회윤리적 제언-포도원 주인이 능력주의를 대처하는 법

이지성 한국기독교사회윤리학회 2022 기독교사회윤리 Vol.54 No.-

Modern society appears to be dominated by meritocracy. In pursuit of meritocracy, our society regards nothing other than ‘merits’ in times of infinite competition among individuals. Even consideration of the disadvantaged is seen as ‘unfair’ in society. Meritocracy has historically emerged as an innovative ideology that destroyed the feudal social status in the past. However, undergoing capitalism and neoliberalism, meritocracy is criticized for disguising justice and being the source of inequality. Therefore, this study aims to examine justice and equality inherent in meritocracy - whether the effort and merit from the perspective of justice are created by individuals or by a mere formality. As an alternative to meritocracy that reproduces inequality, the study explored ‘The Rise of the Meritocracy’ by Michael Dunlop Young and R. H. Tawney’s concept of Christian Ethics - ‘Equality’ and ‘Dignity.’ In conclusion, with the Christian narrative ‘The Parable of Vineyard owner’ that fulfilled the restoration of such dignity, the study proposes an alternative to overcome meritocracy.

Small Strain Niobium Nitride Anode for Potassium-Ion Batteries

이지성,이진우 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

Potassium-ion batteries (KIBs) was recently evaluated as next-generation batteries due to similar standard redox potential of Li/Li⁺ and low cost of potassium resources. However, there are some challenges for searching suitable anode materials. i) Unstable cycle performance of carbonaceous materials due to severe volume expansion ii) metal oxide due to small host for accommodating large ionic size of potassium. In this work, we report ordered mesoporous niobium nitride/N-doped carbon hybrids (m-NbN/NC) as anodes for KIBs for the first time. The electrode delivers reversible capacities of 145 mA h g^-1 at 100 mA g^-1. Additionally, the capacity retention reached almost 100% after 2000 cycles showing superior cyclability. In situ XRD and ex situ SEM analyses were performed to verify the change of m-NbN/NC structure during cycling. Interestingly, mesopore structure was well maintained and accompanied by small strain, which is ascribed to high proportion of surface-controlled reaction.

Organizing Thrombus Mimicking a Cardiac Tumor Located at the Mitral-Aortic Intervalvular Fibrosa

이지성,김완섭,고성민,신제균 대한흉부외과학회 2016 Journal of Chest Surgery (J Chest Surg) Vol.49 No.1

Thrombosis at the left ventricular outflow tract occurs without any detectable heart disease or predisposing factors only extremely rarely. A 48-year-old male visited Konkuk University Medical Center with loss of consciousness one month prior to presentation. Before he visited our hospital, he had been diagnosed with a cardiac tumor, which was located between the left atrium and posterior aortic root, and which was adjacent to both the aortic and mitral valves. Cardiac transplantation was recommended at the other hospital because of the high risk of cardiac dysfunction induced by both aortic and mitral valvular dysfunction after surgical resection. Based on preoperative transthoracic echocardiography, cardiac computed tomography, cardiac magnetic resonance imaging, and intraoperative transesophageal echocardiography, we considered it to be a benign tumor. Complete resection was achieved and the pathology confirmed organizing thrombus. We report a case of organizing thrombus mimicking a cardiac tumor, which was located at the mitral-aortic intervalvular fibrosa of the left ventricular outflow tract without any heart disease.

본훼퍼의 사회윤리에 있어서 책임의 개념

이지성 한국기독교사회윤리학회 1999 기독교사회윤리 Vol.1 No.-

1차원 모델을 이용한 불포화 지반의 침투 및 유출 분석

이지성,김윤태 한국방재학회 2014 한국방재학회 학술발표대회논문집 Vol.2014 No.-

강우로 인한 사면파괴는 전 세계적으로 공통적으로 발생하고 있는 문제이다. 이러한 강우 지반 침투로 인해 발생되는 침투 및 유출은 불포화 지반에서 사면파괴 혹은 침식을 유발시킨다. 본 연구에서는 1차원 모델을 이용하여 불포화 지반의 침투 및 유출량을 산정하여 사면의 안정성에 미치는 영향을 분석하였다. 강우로 인한 침투 및 유출을 실제와 유사하게 모의하기 위해 2011년에 사면파괴가 발생한 춘천지역의 불포화 특성(함수특성곡선, 불포화 투수곡선)을 반영하였고, 확률론적 강우량을 적용하였다. 다양한 조건의 강우강도, 초기 모관흡수력, 투수계수 및 함수특성곡선 영향인자를 반영하여 침투 및 유출량을 산정하였다. 그리고 제안된 모델식과 수치해석 결과와 비교분석을 수행하였다.

애플사 GUI 의 색채 일관성에 관한 연구

이지성,서혜옥 한국공공디자인학회 2012 한국공공디자인학회 학술대회 Vol.2012 No.1