13%Cr 스테인리스강의 표면 질소침투처리에 미치는 Al 첨가의 영향

강창룡,성장현,이해우,김기돈,윤삼석 한국열처리공학회 1999 熱處理工學會誌 Vol.12 No.3

The surface nitrogen permeation of Al alloyed 0.14%C-13%Cr stainless steels was investigated after heat treating at 1050℃∼1150℃ in the nitrogen gas atmosphere. The strong affinity between Al and nitrogen permeates the nitrogen through the interior of the steels. Two precipitates of round type and needle type are observed at the surface layer. These precipitates mainly consist of AlN containing plenty of aluminum. The surface layer of 0.53%Al alloyed specimen shows ferrite phase, while the surface layers of 1.65%Al and 2.27%Al alloyed specimens appear γ plus α phases. The depth of nitrogen permeation depends upon the Al content and microstructure of the matrix. The 1.65%Al alloyed specimen representing α+γ matrix phases at the nitrogen permeation temperature shows the maximum case depth in this experiment. Although the surface hardness increases by raising the Al content of the specimen owing to the increase of nitride precipitation density, the nitride precipitation deteriorates the corrosion resistance in the solution of HCl, H₂SO₄, and FeCl₃.

발전플렌트용 9Cr 페라이트 내열강의 미세조직과 강도특성

강창룡,성장현,이종문,이규현,이문용 한국열처리공학회 2000 熱處理工學會誌 Vol.13 No.1

This present study were investigated effect of Ni contents on the microstructure and strength characteristic in 9Cr ferritic heat-resistant steel added 1.7%W in place of Mo in order to restrain laves phase formation. The result obtained from this study are as follow. Volume fraction, number of particles per unite area and particle size of carbide decreased with increase of Ni contents. Other side, carbides of M_(23)C_6 type was mainly precipitated in this steel, but laves phases could not precipitated in spite of increasing of aging time. With increase of tempering temperature, hardness was increased, and maximum value was showed around 873k by secondary hardening due to precipitation of W₂C type carbide and then, was decreased. Tensile and yield strength due to decrease precipitation amount of carbide and number of particles per unite area was decreased, but elongation and impact value was increased. In case of aged specimen after tempering than tempered specimen, strength was higher and elongation was lower due to increasing of precipitated amount of carbide and number of particles per unite area

Cu 함유 TRIP 형 고장력 강판의 잔류오스테나이트 및 인장특성에 관한 연구

강창룡,성장현,김한군,문원진,김효정 한국열처리공학회 1999 熱處理工學會誌 Vol.12 No.3

Volume fraction and morphology of retained austenite, tensile peoperties of TRIP type high strength steel sheet with Fe-C-Si-Mn-Cu chemical composition have been investigated. The retained austenite of granular, bar and film type existing in specimen was obtained after intercritical annealing and austempering. The granular type retained austenite increased with increase of intercritical annealing and austempering temperature. With increase of intercritical annealing temperature, retained austenite and carbon contents increased. Maximum contents of retained austenite was obtained by austempering at 400℃. The maximum tensile strength was obtained by austempering at 450℃ and maximum elongation was obtained at 400℃. T.S×E.L value increased with increase of retained austenite contents due to the elongation strongly controlled by contents of retained austenite, but tensile strength was affected with various factors such as bainitic structure etc.

신장의 이상회전과 T2Hemivertebra 를 동반한 선천성 일측폐 발육 부전증 1 예

성차경,배성조,강민구,허경억,이대규,도사금 대한내과학회 1986 대한내과학회지 Vol.31 No.2

A case of congenital agenesis of left lung of a 19-years-old female is presented in detail with some review of literature. She had been suffered from mild dyspnea on exertion since early childhood but she was been comfatable unti16 months ago, when frequent upper respiratory infection and dyspnea developed. From 10 days earlier, mild fever was associated and dyspnea on exertion was aggravated. Her past history and family history were not contributary. Physical examination revealed asymmetrical development of both thoracic cage and showed limited respiratory movement of left thorax. There were increased percussion dullness and absent breathing sounds over entire left lung field except left upper lung field. The cardiac dullness was shifted to the left and heart sunds were heard over the 4th ICS X MCL. A roentgenogram of the chest revealed shifting to the left of trachea and mediastinum, homosgenou increased density of left lung, hyperlucency of right lung, and T, hemivertebra, Bronchoscopy showed total absence of left main bronchus. Bronchogram revealed above findings too, but right main bronchus was intact. CT scan revealed agenesis of left lung and herniation of right lung to left hemithorax. Intravenous pyelography showed malrotation of kidney. Pulmonary angioram and cardiac catheterization showed unremarkable findings except total absence of left pulmonary artery.

교류-직류 변환오차 자동 측정시스템

권성원,박영태,조용명,강전홍,김규태 한국센서학회 1998 센서학회지 Vol.7 No.6

A dual-channel automatic ac-do voltage transfer error measurement system in which the output voltages of two thermal voltage converters which are ac voltage standard are directly measured at the same time to reduce the output voltage drift is described. Forward-reverse measurement method by using a two-channel scanner is used to cancel the offset voltage of the voltmeters. The agreements of the 4-V TVC comparison results between other national standards institute and Korea Research Institute of Standards and Science were less than about ±2 ppm in the frequency range of 40 Hz∼100 kHz, and were less than about ±4 ppm at 200 kHz∼1 MHz. Measurement uncertainty is reduced significantly from ?5 ppm of manual system to ±3 ppm of new system(up to 100 kHz) typically and great increase in comparison efficiency has been achieved by this system.

자폐유아의 치료교육용 컴퓨터 학습교재의 실용화 검증연구

이상복,홍강의,정보인 한국정서학습장애아교육학회 1999 정서ㆍ행동장애연구 Vol.15 No.1

This study attempted to evaluate the effectiveness of parent training computer package for children with autism based on the analysis of profiles obtained with the child developmental areas and Autism Behavior Checklists(ABC). The computer package programs were provided for 20 autistic children ranging in CA from 3 to 7 for a period of six months by their own mothers. Subjects demonstrated significant treatment effects in the domains of developmental profiles and ABC. Statistically significant differences were noted. The proportional Change Index was 4.33.

SA 508 강 용접 열영향부의 미세조직과 충격인성의 상관관계

김상호,홍준화,김주학,권순주,이성학,강석영,오세진 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.4

In this study, microstructures of the heat affected zone (HAZ) of SA 508 steel were identified by Mo¨ssbauer spectroscopy in conjunction with microscopic observations, and were correlated with impact toughness. Specimens with the peak temperature risen up to 1350℃ showed mostly martensite, but the microstructures were not changed, much from the base metal because of the minor tempering effect when it was risen to 650℃ or 700℃. With the peak temperature risen to 900℃ over the A₃ temperature, the martensite fraction was reduced, while bainite or martensite island were formed because of the slow cooling from the lower austenite region. As the martensite fraction present inside the HAZ increased, hardness and strengths tended to increase, whereas impact toughness decreased. However, impact toughness of the subcritical HAZ with the peak temperature risen to 650℃-700℃ was seriously reduced after post-weld heat-treatment (PWHT) since carbide particles were of primary importance in initiating voids. Thus, the most important microstructural factors affecting impact toughness were the martensite fraction before PWHT and the carbide fraction after PWHT.

발달장애 발생요인의 예측과 장애아동의 복지모형 개발연구 : 위험요인차원 및 유형을 중심으로 Focused on Risk Pattern Dimensions and Types

정영숙,이상복,정보인,홍강의 한국정서학습장애아교육학회 2000 정서ㆍ행동장애연구 Vol.16 No.2

The main purpose of this study was to analyze specific risk factor types through examining the group characteristics of children with developmental disabilities and risk factor structure for the children. The result showed that children with developmental disabilities have diversely structured heterogeneous groups based on the characteristics of risk factors. It also showed that the risk factor for children was determined by three dimensions which include impulsivity-aggression, immaturity, and neurosis. The critical factor in forming risk factor types depends on how much the child lacks coordinating ability, self-intensity, intelligent ability, and physical strength, compared to his/her impulsivity, self-injury, and lack in feeling of reality and identity. Also, the degree of the child's anxiety and guilty conscience was a critical factor in determining structural dimensions of risk types compared to the degree of the child's dependency and/or withdrawal. The risk factor types were classified into three groups: mild-withdrawal type, impulsive-aggressive type, and immature-neurotic type. The probability that each child was exposed to each of the risk factor types was dependent on the parents' psychological stress, family function, birth weight of the child, parents' educational level, family income level, mother's maternity age for the child, time of diagnosis for developmental disability.

발달장애 발생요인의 예측과 장애아 가족의 복지모형 개발연구(2) : 발달지체아동의 위험차원과 가족적 대처방안 Family Coping Strategies for At - Risk Children

정영숙,이상복,정보인,홍강의 한국정서학습장애아교육학회 2001 정서ㆍ행동장애연구 Vol.17 No.1

The purpose of this study was to identify potential risk dimensions for at-risk children and to find family copying strategies based on family stress, perception of the situation, and coping strategies. This study assumes that the presence of children at risk may be considered a potential stress factor for the families, and the family's perception of their situation influences the degree of distress experienced by the family. Data were factor analyzed, and the results revealed four different risk dimension types : impulse-aggressive, physical-immature, cognitive-immature, social-immature dimension. Risk dimension types are likely to correlated with family stress, perception of the situation, and coping strategies. Similarities and differences in risk dimension types are discussed, and implications for family copying strategies are provided.

RFID 기술을 적용한 감염성폐기물 관리방안에 관한 연구

정양재,성닥창,강헌찬,강대성 동아대학교 환경문제연구소 2006 硏究報告 Vol.28 No.1

Recently. we are recognition that inflection of Infectious Wastes is dangerous. Management and handing of Infectious Wastes bring into relief. In this paper, we process using RFID(Radio Frequency Identification) that is the oncoming generation of high technology. real - time monitoring from a pollution source of Infectious Wastes to treatment of Infectious Wastes. The reason is solution the reinfection of Infectious Wastes illegal measure. Through this paper propose study, we offer a plan to slove inefficient business environment which is appeared management like computerization input to deal with paper working and wed application by management officer.