Microstructure, Tensile and Fatigue Properties of Al–5 wt.%Mg Alloy Manufactured by Twin Roll Strip Casting

Joon‑Young Heo,Min‑Seok Baek,Kwang‑Jun Euh,Kee‑Ahn Lee 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.5

This study investigated the microstructure, tensile and fatigue properties of Al–5 wt.%Mg alloy manufactured by twin rollstrip casting. Strips cast as a fabricated (F) specimen and a specimen heat treated (O) at 400 °C/5 h were produced andcompared. In the F specimen, microstructural observation discovered clustered precipitates in the center area, while in theO specimen precipitates were relatively more evenly distributed. Al, Al 6 (Mn, Fe), Mg 2 Al 3 and Mg 2 Si phases were observed. However, most of the Mg 2 Al 3 phase in the heat-treated O specimen was dissolved. A room temperature tensile test measuredyield strength of 177.7 MPa, ultimate tensile strength of 286.1 MPa and elongation of 11.1% in the F specimen and167.7 MPa (YS), 301.5 MPa (UTS) and 24.6% (EL) in the O specimen. A high cycle fatigue test measured a fatigue limit of145 MPa in the F specimen and 165 MPa in the O specimen, and the O specimen achieved greater fatigue properties in allfatigue stress conditions. The tensile and fatigue fracture surfaces of the above-mentioned specimens were observed, and thisstudy attempted to investigate the tensile and fatigue deformation behavior of strip cast Al–5 wt.%Mg based on the fi ndings.

FUNTION APPROXIMATION OVER TRIANGULAR DOMAIN USING CONSTRAINED Legendre POLYNOMIALS

( YOYNG JOON AHN99 ) 한국산업응용수학회(구 한국산업정보응용수학회) 2005 한국산업정보응용수학회 Vol.9 No.2

한국인의 연, 망간, 알루미늄 및 실리콘의 혈중 농도

김정만,안정모,김원술,김정일,신해림,정갑열,김준연 동아대학교 산업의학연구소 2000 산업의학연구소 논총 Vol.- No.5

Blood Lead, Manganese, Aluminium and Silicon Concentrations in Korean Adults Jung Man Kim, Jung Mo Ahn, Won Sul Kim1), Jung Il Kim2), Hai Rim Shin, Kap Yeol Jung2), Joon Youn Kim Department of Preventive Medicine, College of Medicine and Industrial Medicine Research Institute. Dong-A University Department of Health Care, Handong University Sunlin Presbyterian Hotpital1) Department of Occupational Medicine, College of Medicine, Dong-A University2) 0bjectives : This study was performed to determine the reference values of blood lead, manganese, aluminium, and silicon in healthy adults. Methods : The subjects were 132 (67 male and 65 female), and classified to three age groups (≤39,40∼49, and 50≤). Hood lead, manganese and aluminium were analyzed by atomic absorption spectrophotometer, and blood silicon was analyzed by direct current plasma optical omission spectrometer. Results : Blood lead levels(geometric mean, S.D) were (3.49, 1.70) ㎍/dL in male auld (3.04, 1.65) ㎍/dL in female, but the difference is not significant, and there was no significant difference between age groups. Mean blood manganese level was 0.99±0.41㎍/dL, and there was no significant difference between sex or age groups. Mean blood aluminium level was 0.59±0.35㎍/dL and there was no significant difference between sex or age groups. Mean blood silicon level was 54.41±27.64㎍/dL in male and 43.34±23.51㎍/dL in female, and the level in male was significantly higher than that in female (p〈0.05). There was significant difference between age groups, and the oldest showed the highest level in male (p〈0.05), but no significant difference between age groups in female. Conclusions : Authors hope that this study would provide basic data for determininig reference values and evaluating health effects.

서혜부 유리 피판술을 이용한 Romberg씨 질병의 치험

안덕균,김준범,최은정,강동구,최재구 건국대학교 의과학연구소 1993 건국의과학학술지 Vol.3 No.-

본 건국대학교 의과대학 성형외과학 교실에서 Romberg씨 질병으로 좌측의 안면 함몰을 주소로 내원한 여자 환자 1례에서 탈상피화시킨 서혜부 유리 피판술을 시행하여 좋은 결과를 얻었기에 이에 문헌 고찰과 함께 보고하는 바이다. Romberg's disease is progressive hemifacial atrophy, which begins before the age of 20-years, affecting the subcutaneous tissue and skin with later involvement of the muscle and osteocartilagenous frame work. The disease may be heralded by pigmentary changes of the hair, skin, or iris. When present, atrophy may originate from the cutaneous stigmata and may become so sharply delimited by the midline. There are a number of methods to correct the soft tissue deformity of the face. We had experienced 22-year old female patient who had a moderate soft tissue atrophy on the left side of the face. The patient was treated with a de-epithelized groin free flap. Superficial circumflex iliac vessels were used as donor pedicle and the superficial temporal vessels were recipient vessel. Initially moderate bulkiness was noted but after 6 months follow-up period the external contour was good and the patient satisfied. A case presentation and review of literatures are the basis of this report.

위팔근육 위축 양측마비 2예

안준성,김민아,김상진,김응규 인제대학교 2006 仁濟醫學 Vol.27 No.-

Brachial amyotrophic diplegia, a relatively stable variant of motor neuron disease, is characterized by weakness that is isolated to upper limbs and spared lower extremities, respiratory and bulbar musculature. This disease should be differentiated from other disease such as multifocal motor neuropathy, amyotrophic lateral sclerosis, monomelic amyotrophy and progressive muscular atrophy. We report two cases of brachial amyotrophic diplegia.

도시 노숙자의 주요 정신장애에 관한 역학 연구

안준호,홍진표,유제춘,박종익,이철,한오수 大韓神經精神醫學會 2001 신경정신의학 Vol.40 No.2

외환위기 이후 대도시를 중심으로 노숙자들이 급증하여 이들이 심각한 사회문제로 등장하였다. 외국의 연구에 의하면 노숙자 중 상당수가 만성 정신질환을 앓고 있으며, 정신질환이 노숙의 원인 및 예후와 밀접한 관련이 있다고 한다. 그러나 국내에서는 아직 노숙자의 정신장애의 유병률에 관하여 알려진 바 없으므로 이에 대하여 조사하였다. 방법: 1998년 말부터 1999년 초까지 부산지역의 쉼터 두 곳에 거주하는 노숙자 216명을 대상으로 인구학적 자료에 대한 설문조사를 한 뒤 Structured Clinical Interview for DSM-Ⅳ(SCID)을 이용하여 Axis Ⅰ의 주요 정신장애를 진단하였다. 이들의 정신장애의 평생유병률 및 현재유병률을 국내 일반인구 및 외국 노숙자의 정신장애의 유병률과 비교하였다. 결과: DSM-Ⅳ Axis Ⅰ의 정신장애 중 기분장애, 정신병적 장애, 물질사용장애에 대한 진단 평가 결과 상기 정신장애의 전체 평생유병률은 60.1%, 현재유병률은 35.7%이었다. 그 중 주요우울장애의 평생유병률 이 22.5%로서 외국의 노숙자에 대한 역학연구 결과와 비교해 볼 때 높은 수준이었고 알코올 사용 장애의 평생유병률은 47.4%이었다. 정신병적 장애의 평생유병률은 3.8%이었고, 그 중에서도 정신분열병의 평생유병률은 1.9%이어서 외국의 노숙자에 대한 연구결과보다 낮은 편이었다. 결론: 국내 노숙자에서 기분장애와 물질사용장애가 주된 정신장애였으며 정신분열병 등 정신병적 장애의 유병률은 외국에 비해 낮은편이었다. 이러한 정신장애를 가지고 있는 노숙자에 대하여 접근하고 치료하기 위한 대책이 마련되어야 할 것이다. Objective:As homeless people increased in urban areas after the economic crisis in Korea, they became a serious social problem. Foreign research showed that many homeless people had chronic mental illnesses which were closely related with the cause and prognosis of homelessness. But very little was known about the prevalence of mental disorders in Korean homeless people. This study tried to capture the overall picture of mental disorders in homeless people. Method:The study subjects were 216 homeless people who stayed at two Pusan shelters between late 1998 and early 1999. Questionnaires on sociodemographic data were administered to the subjects, and then diagnoses of major DSM-IV Axis I mental disorders were made using Structured Clinical Interview for DSM-IV Axis I Disorders(SCID). The lifetime and current prevalence of mental disorders in this study were compared to those from other studies in Korean general population and in foreign homeless people. Results:The lifetime prevalence of major DSM-IV mental disorders(mood disorders, psy-chotic disorders, and substance use disorders) of 216 homeless people was 60.1%, and current prevalence was 35.7%. The lifetime prevalence of major depressive disorders was 22.5% which was higher than that of foreign studies. The lifetime prevalence of alcohol use disorder was 47. 4%. The lifetime prevalence of psychotic disorders was 3.8%, and among them the lifetime prevalence of schizophrenia was 1.9% which was lower than that of foreign studies. Conclusions: In Korean homeless people, mood disorders and substance use disorders were the main mental disorders and psychotic disorders such as schizophrenia were less than in foreign homeless people. The plans to approach and treat homeless people with mental disorders should be made.

세균성 수막염에서 발생한 치명적 뇌경색 1례

안준성,김민아,김상진,김응규 인제대학교 2006 仁濟醫學 Vol.27 No.-

Bacterial meningitis is frequently fetal or lead to severe neurological impairment. Cerebral infarction is a well known sequele of meningitis, occurring in as many as 10-20% of patients. But fetal cerebral infarction in bacterial meningitis is rare. We report a 61 year old woman who was admitted due to fever, headache and mental change for 3 days. On admission 7 days follow up Brain-CT revealed large and massive infarctions on both hemispheres. When bacterial meningitis is caused by Streptococcus pneumonia, there is a high prevalence of cerebral infarctions. The underlying mechanisms of cerebral infarction in bacterial meningitis are vasculitis, thrombosis, arachnoiditis, and compression of the arterial supply at the foramen magnum by herniation of the cerebellar tonsil.

하수 2차 처리수 재이용을 위한 저압 및 중압 고도산화시스템의 성능평가

안규홍,안석,맹승규,김기팔,홍준석,정민우,권지향,Ahmed, Zubair 대한상하수도학회 2003 상하수도학회지 Vol.17 No.4

In the present study, the feasibility of UV/H₂O₂ systems was investigated using low and medium-pres sure lamps on biologically treated wastewater effluents for secondary effluent reclamation. Two types of UV lamps were used as the light sources (a 33W lowpressure mercury lamp and a 350-W mediumpressure mercury lamp). The results from these UV systems showed that the removal of organic compounds could be achieved in the contact time of longer than 30min (i.e., low UV doses). Efficiencies of color removal and disinfection were far better than those of organic matters measured as TOC, DOC and TCOD_(cr). In the low pressure lamp UV system, it has been found that DOC and color removals were 60.9 and 86.2% with 50㎎/L of H₂O₂ and contact times of 30 minute, respectively. Whereas, with the mediumpressure lamp UV system, TOC, DOC and color removal were 27.1, 5.6 and 95% with 14.3㎎/L of H₂O₂ and 14 minute of contact times, respectively. Both systems could be applied for the reclamation of secondary effluent treated with biological treatment processes.

실과 단정한 옷차림 단원의 CD-ROM 타이틀의 개발과 효과

안준엽,김채복 韓國實科敎育硏究學會 1999 實科敎育硏究 Vol.5 No.2

The purpose of this study is to develop CD-ROM title on Neat Dressing unit of practical arts for the third grade students of elementary school, and to compare and verify the academic achievement between the group received computer aid lesson by using the developed CD-ROM title and the group received the traditional lesson. The results of survey were as followings. 1. Computer aid lesson by using CD-ROM title improved the academic achievement scores on learning Neat Dressing unit of practical arts for the third grade students of elementary school. 2. The middle subgroup with lesson by using CD-ROM title scored higher than the middle subgroup with traditional lesson.

朝鮮時代 東軒建築의 樣式學的 考察 : In Chung Nam Local Province 忠南地方을 중심으로

安駿鎬,李達勳 大田大學校 産業技術硏究所 1997 산업기술연구소 論文集 Vol.8 No.1

This traditional government office buildings of Choson Dynasty which exist in our country can be divided into two types (central and local government office buildings). Among them, the local government office buildings of Choson Dynasty are compoded of Nae-a, Dong-hun, Gaeg-sa, Hyang-Chung and Yook-bang-guan-chung. This study focuses on the Dong-hun, the central part of the local government office building, and tried to discover the specific regional featues of its construction type and analyze these various peculiarities focused on 14 local government buildings which can be found in Chung Nam local province. The results of this study are followings : 1. The shape of Dong-hun plan : It has almost '一'letter shape plan symmetrized On-dol on each side of Daechung (a king of floor) and Tae-maru in front. 2. The type of bracket structure : The bracket structures of Dong-hun is almost Muchulmok-choikong (10) and the rest of those are types of Min-do-li house(4). Therefore most of those are the buildings of earlier Choson Dynasty. 3. The form of the frame : Most of the frames are composed of double girders and five cross beams. 4. The form of the king post : There are six trapezoid king posts, four Paryun king posts and no Dongjaju king post. And the rest three king posts are hard to identify because of the transform of inner space. 5. The form of the roof : Dong-hun has a combination of trapezoid and triangular shape roof and most of them have single eaves(10).