Correlation Between Primary Si and Silicide Refinement Induced by Ultrasonic Treatment of Multicomponent Al–Si Alloy Containing Ti, Zr, V, and P

Jae‑Gil Jung,Young‑Hee Cho,Tae‑Young Ahn,Jae‑Hee Yoon,Sang‑Hwa Lee,Jung‑Moo Lee 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.5

The correlation between primary Si and silicide refinement induced by ultrasonic treatment (UST) of multicomponent Al–Sialloy containing Ti, Zr, V, and P was investigated. UST significantly refined the primary Si phase owing to cavitation-inducedwetting and deagglomeration of MgAl2O4particles. Lowering the UST finish temperature caused deterioration of the degreeof primary Si refinement, instead leading to silicide refinement. Cavitation-induced silicide nucleation on wetted MgAl2O4consumed the MgAl2O4particles, particularly in the case of primary Si nucleation. Similarly, the formation of an AlP phaseon the silicide phase reduced the nucleation efficiency of the AlP phase. Poisoning of the MgAl2O4and AlP phases by thesilicide phase was responsible for the deterioration in primary Si refinement. Room-temperature tensile strength and hightemperatureelongation were increased by UST and were dependent on the size of primary Si.

자본시장의 완전개방과 그에 따른 당면문제

윤재희 안양대학교 1997 논문집 Vol.17 No.-

Korean government has gradually opened capital market against foreign countres. However, Korea' economy has recently confronted with serious crisis on holding foreign exchanges. Due to this problem the government eventually decided to open capital market perfectly. In this regard, first of all, this study shows the relation between free capital market and the exchange rate variability, and how exchange rate variability affects the export industries. Secondly, this study tells us how the institutional investors can solve its problems facing with free capital market. To deal with the second subject is specially important to get out of current economic difficultly, so called IMF period, because stock market depends highly on the behavior of the institutional investors. To analyze above two subjects, this atudy, firstly, describes the history of Korea's exchange rate system to predict its future. Secondly, basic conditions for the free capital market are analyzed. Thirdly, how the exchange rate variability affect the expoting sector is explained by using microeconomic analysis. Finally, the problems of institutional investors facing with the free capital market are analyzed.

남북철도 연결사업에 있어서 주변국가의 경제적 효과

윤재희 안양대학교 복지행정연구소 2002 福祉行政硏究 Vol.18 No.-

TKR 연결사업은 물류비용의 개선, 수출채산성 향상, 자원의 안정적 확보, 대유럽 교역량 증대로 인한 대 미국의존도 개선, 관광수입의 증대, 시베리아 및 몽골의 자원개발 투자증대, 동북 및 동남아 단일시장 기대 등을 들 수 있는 반면 해운 수송물량의 감소, 국내 농수산물과 같은 1차산업의 타격, 교류증대로 인한 사회문제, 해상운송에 비해 요율체계 고가, 북한 철도시설 노후로 인한 복선화 및 직선화 비용발생 등이 있을 수 있다. 또 주변국들에 미치게 될 경제적 파급효과가 있는데 동북아시아 화물운송 시스템이 해상운송 시스템에서 육상운송을 연계하는 복합운송 시스템으로 전환되어 철도 실크로드를 중심으로 주변국들의 경제, 사회가 발전하게 될 것이다라는 것이다.

천해역에서 장파의 변형에 대한 실험적 연구

윤영호,조재희 도립 강원전문대학 2000 道立 江原專門大學 論文集 Vol.3 No.-

The propagations of surface wave in the region with depth discontinuity caused by dredging for navigation channel, and reclamation etc. induce the soil troubles such as moorage's siltation and beach erosion. In this paper, at first experiments were conducted to investigate the wave deformation over rectangular pit. The effects of many parameters such as the depth ratio, shape ratio of pit, wave steepness and period on the wave deformation near the pit are investigated. Secondly, numerical analysis is performed. Wave field is divided into two regions which are the interior and the exterior region of the pit, respectively. The governing equations for the long waves over the pit are integrated. Application of Green's second identity using the appropriate Green functions in each region leads to a pair of integral equation for the potential and it's normal derivative as unknown variables in each region. The numerical experiments are conducted by solving above integral equations using the boundary element method. Finally, The measured values are compared with the computed ones. The results show that the computed values are underestimated a little, however, two values are relatively good agreements.

H.-R. 히치코크와 P. 존슨의 저서 『국제양식: 1922년 이후의 건축』의 도해와 기술내용에 대한 분석을 통해 본 국제양식의 시각적 특질과 그 조형어휘

윤재희,이화인 광주대학교 2000 産業技術硏究 Vol.14 No.-

국제양식은 1920년대부터 1960년대에 걸쳐서 전세계에 광범위하게 유포되었으며 국내에서도 이러한 유형의 건물들이 다수 존재하고 있다. 그러나, 그 개념이 모호하기 때문에 이 용어를 처음으로 사용한 히치코크와 존슨의 저서를 자세하게 분석함으로서 그 개념을 정확하고 구체적으로 파악하고 재정립할 필요가 있다. 따라서, 본 논문은 미국 뉴욕 근대미술관에서 개최된 국제양식전과 함께 출판된 저서 『국제양식 : 1922년 이후의 건축』의 내용, 즉 기술내용과 도해를 분석하여 국제양식의 시각적 특질과 그 조형어휘를 연구한 것이다. 『국제양식: 1922년 이후의 건축』에 관한 기술내용과 도해를 분석하여 국제양식의 시각적인 특질과 그 조형어휘를 보다 구체적으로 연구한 결과 저자인 건축사가 히치코크와 존슨이 제시한 국제양식의 3가지 원리는 1) 상자형의 건축 2) 평탄한 표면 3) 수평성 강조 4) 규칙성 5) 무장식성 이라는 5가지의 시각적인 특질을 지닌 건축으로서 보다 구체적으로 재규정할 수 있다. 히치코크와 존슨이 정의한 바 있는 국제양식의 3가지 원리를 보다 구체적으로 설명하는 시각적인 특질을 통하여 국제양식의 건축을 재정의하면 이러한 5가지의 시각적 특질을 지니고 있는 건축이라고 말할 수 있다. 아울러서, 이러한 시각적인 특질을 나타내기 위하여 사용된 조형어휘로는 구조체의 분리, 필로티, 캔틸레버, 평지붕, 수평창과 코너창, 전면 유리창, 평탄한 벽면, 수평띠, 간결한 프레임 등이 있다. The term "International Style" was first used by Hitchcock and Johnson as the title to the accompanying book of the first international exhibition of modern architecture, held at the Museum of Modern Art, New York in 1932. In order to understand the International Style it is important to consider the principles elaborated in the examples presented by Hitchcock and Johnson. Their principles are "architecture as volume", "regularity rather than axiality", and "avoidance of applied decoration". But because of an abstract and vague notion of these principles, first of all, I made an detailed analysis of the table of contents in 「International Style : Architecture since 1922」, a book written by Hitchcock and Johnson. This analysis showed that the International Style marked by several visual characteristics and formal vocabularies. And then I will define the concrete concept of the International Style with the aid of these visual characteristics and formal vocabularies. The results of this study are as follows: 1. By means of the detailed analysis of the original texts and illustrations in 「International Style : Architecture since 1922」, written by Hitchcock and Johnson, I can redefine the concept of the International Style on the basis of their three principles as the modern architecture having the five visual characteristics.

환율변동성이 한국수출에 미치는 영향

윤재희 안양대학교 사회과학연구소 1995 社會科學硏究 Vol.3 No.-

Abstract The adoption of the floating exchange rate system in 1980 has generated considerable interest about the question of exchange rate volatility and its impact on the level of export of Korea. The purpose of this study is to investigate empirically the effects of exchange rate risk on the export performance of Korea. As expected, in most cases, the bilateral exchange rate volatilities of floating exchange rate regime are greater than those of pegged exchange rate regime. Aggregate estimation of an export supply function shows that exchange rate volatility is negatively related to exports and that the change in exchange rate regime is associated with a structural shift in the export equation. Bilateral estimation results show that most countries have positive and significant signs for the coefficients of foreign income, price level, and exchange rates. The only negative impact is the volatility of exchange rate. This tells us that the volatility of exchange rate can be a significant factor in exports of Korea. This also implies that the exchange rate policy of Korea should be carried out for the stability.

분리 대두단백의 소화율과 전기영동패턴에 미치는 Phytate의 영향

윤재영,조희경,이서래 이화여자대학교 생명과학연구소 1993 생명과학연구논문집 Vol.4 No.-

Phytate 함량이 다른 두 분리 대두단백(HSPI; high-phytate soy protein isolate, LSPI; low-phytate soy protein isolate)을 제조하여 pH 및 phytate 첨가량이 그들의 용해도와 소화율에 미치는 영향을 알아보았고 분리 대두단백을 용해도에 따라 분별한 후 그들의 특성을 전기영동을 통하여 알아보았다. LSPI와 HSPI 모두 분자량이 13.6~81.1 kDa 에 이르는 단백질 성분으로 이루어져 있으며 산성 pH에서 18.0~35.0 kDa의 단백질은 phytate와 잘 결합하지 않는 특성을 가졌다. LSPI를 용해도에 따라 분별하였을 때 gliadin을 구성하는 단백질은 pH2에서 phytate와 쉽게 결합하지 않았다. 대두 단백질은 pepsin 소화율은 phytate 첨가량이 증가할수록 크게 저하되었다. This study was carried out to examine the effects of phytate addition on the solubility and digestibility of the low-phytate soy protein isolate (LSPI) and high-phytate soy protein isolate (HSPI). In SDS-polyacrylamide gel electrophoresis of soy protein isolate, different patterns of proteins were observed in both HSPI and LSPI at various phytate and pH levels, suggesting that phytate may bind specifically to certain protein fractions at a particular pH. For example, proteins of M.W. 1.8~3.5kDa resisted phytate binding at acidic pH. LSPI was fractionated into albumin, globulin, gliadin and glutelin; and phytate was shown to bind with difficultly to all three gliadin bands. Effects of phytate on the pepsin digestibility of soy proteins were apparent, especially in the short term digestion.

클랩(Clap)과 노말(Normal) 스케이트 착용에 따른 남ㆍ여 스피드 스케이트 출발 구간의 운동학적 분석

윤희중,나윤수,최재용,김태삼 한국체육대학교 체육과학연구소 2000 韓國體育大學校附屬 體育科學硏究所論文集 Vol.19 No.1

The purpose of this study is to examine the kinematic characteristics of starting phase of players weared clap and normal skate in speed skating. The subjects of this study were current members of high ranked skaters in university. The Direct Linear Transformation(DLT) technique was employed to obtain 3-D position coordination of 22 joint points. Butter-worth low-pass filtering method was used to data smoothing at cut-off frequency of 7.4Hz. From the results of this study, the following conclusions were drawn; 1.At the of landing, male athlete showed slightly fast time in the first left-step and they also showed take-off by fast swing motion during gliding. 2.To get propel acceleration, female athlete showed large tranverse displacement and, on the other hand, male athlete showed large horizontal displacement. According to this results, COG showed steep change of motion in the high position during starting. 3.In the velocity of COG, both male an female athlete show a gradual rise-pattern of the velocity rate, In the velocity of skate front blade, they showed the swift change of the velocity during the second and third phase. 4.In the front angle of trunk, both and female athlete showed the big motion of trunk by the change of angle. In the angle of lower-segments, the better record athlete have, the faster motion of flexion and extention. Especially, female athlete showed the flexion of the angle-change and do not fast swing. In the knee, male athlete show take-off motion as increasing angle of left knee during starting, On the other hand, female athlete showed unnecessary pre-motion by decreasing knee angle and increasing it again.

Carotid Siphon 질환의 경안와 초음파와 자기공명 혈관조영술의 진단적 가치

배희준,윤병우,노재규 대한신경과학회 1999 대한신경과학회지 Vol.17 No.1

Lymphangioma에 의한 거설증을 지닌 환자의 개교합 증례보고 : A CASE REPORT

윤희훈,이상대,김영재,장기택,한세현,이상훈 大韓小兒齒科學會 2004 大韓小兒齒科學會誌 Vol.31 No.2

Lymphangioma는 림프관에 나타나는 양성종양으로 림프관의 증식을 특징으로 한다. 이 종양의 대부분은 출생 시에 나타나며 종양의 95%정도가 10세 이전에 나타난다. 구강 내에 발생하는 경우에는 혀에서 가장 호발하며 거설증을 야기한다. 대개 양측성으로 혀의 전방 2/3부위에 나타나며 불규칙한 회색과 핑크빛을 띤 소절형태를 보인다. 본 증례 모두에서 환아들은 출생당시 혀에 lymphangioma를 지니고 태어나 거설증을 보였으며 이로 인해 개교합과 하악과성장 양상을 나타내었다. Lymphangioma에 의한 비정상적인 혀의 비대에 의해 환아의 구강과 두개안면부의 주위조직에 대한 적응 결과로 나타난 소견을 관찰하고 관련문헌을 고찰하여 다소의 지견을 얻었기에 보고하는 바이다. Lymphangioma is a benign tumor of lymphatic vessels. The majority of cases are present at birth and 95% of the tumors aroused before the age of 10 years. Oral lymphangioma may occur at various sites but are most frequent on the anterior two thirds of the tongue, where they often result in macroglossia. The lesions present nodularity with gray and pink projections. In the present cases, all the patients who had the macroglossia combined with lymphangioma showed openbite and mandibular prognathism. The purpose of this paper was to report the dental and craniofacial findings of macroglossia combined with lymphangioma and review the pertinent literature through the cases.