기계적으로 밀링된 나노결정 Al-14wt%Ni-14wt%Mm 합금 분말의 열 안정성과 미세조직

홍순직,이윤석,천병선 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.10

Mechanical milling has been performed for Al-14 wt%Ni-14 wt%Mm(Mm=misch metal) alloy powders rapidly solidified by the gas atomization method. The microstructure, hardness, and thermal stability of the powders were investigated as a function of milling time using X-ray diffraction(XRD), transmission electron microscopy(TEM), Vickers micro-hardness tester and differential scanning calorimetry(DSC) methods. In the early stage of milling, a cold-welded layer with a fine microstructure was formed along the edge of the milled powder (Zone A). The interior of the powder remained unworked (Zone B), resulting in a formation of two-zone microstructure. With increasing milling time, the nanocrystallite size decreased gradually reaching a size of about 10-15 nm and the lattice strain increased reaching a maximum value of about 0.7% after milling for 200 hours. The microhardness of the mechanically milled powder was 132 kg/㎟ after milling for 72 hours, and it increased to 290 kg/㎟ after milling for 200 hours because of the presence of fine nano structured phases.

구상흑연 주철의 열처리 조건이 기계적 성질에 미치는 영향

전언찬,정하돈,김순경,김용직 東亞大學校 大學院 1998 大學院論文集 Vol.23 No.-

Because the spheroidal graphite cast iron, the cast iron cristallized the graphite to sphericity during the solidification process after annexing Mg etc to the general grey cast iron furnace, the form of the graphite is more spheric than the grey cast iron, has the less notch effect, it is a very excellent metal material on the strength an toughness due to the decrease of the stress concentraion. Therefore, the case which uses it instead of forfing or case steel material used for the industrial machinery parts of various kinds and automobile parts is increasing gradually. The purpose of this study is to increase abration resistance after improving the hardness of the sphericity graphite cast iron used as the valve seat of air compressor. We obtained the following result through experiment on the change of structure and mechanical property according to the heat treat cycle. Because the abration resistance is closely related with the volume of martensite, the hardness and the aration resistence have improved and the structure of martensite has increased as the cooling rate is fast. Therefore, the best heat treatment which considers tensile strength and elongation percentage, the most suitable method, is that austempering is done the constant temperature process about 2 hours at 750℃ then the cooling is done in the condition of opened furnare after making the condition of austenitizing do the constant temperature process ofr 2 hours at 950℃.

Prediction of changes in distribution area of Scopura laminate in response to climate changes of the Odaesan National Park of South Korea

Soon Jik Kwon,Tae Geun Kim,Youngjun Park,Ohseok Kwon,조영호 한국생태학회 2015 Journal of Ecology and Environment Vol.38 No.4

This study was performed to provide important basic data for the preservation and management of Scopura laminata, a species endemic to Korea, by elucidating the spatial characteristics of its present, potential, and future distribution areas. Currently, this species is found in the Odaesan National Park area of South Korea and has been known to be restricted in its habitat due to its poor mobility, as even fully grown insects do not have wings. Utilizing the MaxEnt model, 20 collection points around Odaesan National Park were assessed to analyze and predict spatial distribution characteristics. The precision of the MaxEnt model was excellent, with an AUC value of 0.833. Variables affecting the potential distribution area of S. laminata by more than 10% included the range of annual temperature, seasonality of precipitation, and precipitation of the driest quarter, in order of greatest to least impact. Compared to the current potential distribution area, no significant difference in the overall habitable area was predicted for the 2050s or 2070s. It was, however, demonstrated that the potential habitable area would be reduced in the 2050s by up to 270.3 km from the current area of 403.9 km; further, no potential habitable area was anticipated by the 2070s according to our predictive model. Taken together, it is anticipated that this endemic species could be significantly affected by climate changes, and hence effective countermeasures are strongly warranted for the preservation of habitats and species management.

RF 열플라즈마를 이용하여 제조된 이차전지 음극활물질용 탄소-실리콘 복합소재의 카바이드 형성 제어 연구

Soon-Jik Lee,Myoung-Sun Shin,Jeong-Mi Yeon,Sun-Yong Choi 한국진공학회 2018 한국진공학회 학술발표회초록집 Vol.2018 No.8

초등학교 체육수업시간의 재미요인, 수업몰입 및 수업만족도의 관계

권순직 ( Soon Jik Kwon ),정구인 ( Koo In Jung ) 서울敎育大學校 初等敎育硏究所 2014 한국초등교육 Vol.25 No.3

근래에 초등학생들의 다양한 문제를 해결하기 위해 체육교육을 활성화하고 있고, 또한 학생들의 심리적 요인을 분석하여 체육수업을 촉진하는 방안을 모색하고 있다. 본 연구는 초등학교 체육수업시간에서 재미요인이 수업몰입에 영향을 미치는가, 재미요인이 수업만족도에 영향을 미치는가, 그리고 수업몰입이 수업만족도에 영향을 미치는가를 살펴보았다. 연구대상은 서울시에 소재한 초등학생 3~6학년을 모집단으로 16개 학급 총 425명에게서 수집한 자료를 상관관계분석 및 다중회귀분석을 통하여 분석한 결과, 재미요인은 수업몰입에 영향을 미치는 것으로 나타났다. 또한 재미요인이 수업만족도에 영향을 미치는 것으로 나타났다. 그리고 수업몰입이 수업만족도에 영향을 미치는 것으로 나타났다. 이러한 결과로 볼 때 수업의 과정이나 활동 자체에 관한 몰입과 재미요인이 수업만족도에 긍정적인 영향을 미친다는 것을 알 수 있었으며, 이와 관련된 심층적인 연구와 체계적인 교수·학습활동에 관한 후속연구가 필요하다고 본다. 또한 유능성에 높은 반응을 보인 학생들을 위한 수준별 지도 방안도 필요한 것으로 나타났다. Elementary school students have recently been encouraged to improve problem-solving skills with promotion of sports. The purpose of this study is to seek ways to promote physical education by analyzing psychological factors of elementary school students. The subjects of the study are 425 students in sixteen classes ranging from third to sixth grade of the elementary school located in Seoul. Correlation analysis and multiple regression analysis were conducted to identify causal relationship among enjoyment factor, class flow, and satisfaction in physical education classes. The results were produced as follows: First, enjoyment factor appeared to have effect on class flow in class. Achievement did not have significant effect on self-fulfilling experience and integration of process unlike other factors. Second, enjoyment factor appeared to have effect on satisfaction in class. Every enjoyment factor had positive effect on satisfaction in class, except competence of enjoyment factor, which appeared to have negative effect on instruction achievement and coursework. Third, class flow appeared to have effect on satisfaction in class. Integration of process did not have effect on satisfaction, but self-fulfilling experience and behavior-awareness concurrence appeared to have positive effect on satisfaction in class. In the view of result of this study, and process, absorption of activity itself and enjoyment factor have more effect than outcome of class or evaluation factor on satisfaction. Also, method of teaching and learning by level shall be needed for the students who showed high response on competence. L

ATSC-M/H 수신기를 위한 주파수 영역 등화 기술

권순직(Soon Jik Kwon),김영준(Young Jun Kim),박경원(Kyung Won Park),위정욱(Jung Wook Wee),조용수(Yong Soo Cho) 한국통신학회 2010 한국통신학회 학술대회논문집 Vol.2010 No.11

Stereospecific Synthesis of γ,δ‐Diamino Esters

Chin, Jik,Kwon, Soon Ho,Kim, Hyunwoo,Chin, Peter,So, Soon Mog,Kim, B. Moon WILEY‐VCH Verlag 2014 EUROPEAN JOURNAL OF ORGANIC CHEMISTRY Vol.2014 No.4

<P><B>Abstract</B></P><P>γ,δ‐Diamino acid structural motifs are commonly found in bioactive molecules. We report a one‐pot reaction for the synthesis of γ,δ‐diimino esters with two adjacent chiral centers in enantiomerically pure form through diaza‐Cope rearrangement reaction of diimines formed from (<I>R</I>,<I>R</I>)‐1,2‐bis(2‐hydroxyphenyl)‐1,2‐diaminoethane (<I>hpen</I>) and aldehydes. DFT computation provides interesting insights into the stereospecific rearrangement reaction. The crystal structure of a product diimine formed from the reaction of (<I>R</I>,<I>R</I>)‐<I>hpen</I> and 2,6‐dichlorobenzaldehyde shows that the reaction gives the product diimine in <I>S</I>,<I>S</I> configuration.</P>

Stereospecific synthesis of a twinned alanine ester

Chin, Jik,Kwon, Soon Ho,Moozeh, Kimia,So, Soon Mog,Lough, Alan J.,Kim, B. Moon The Royal Society of Chemistry 2013 Organic & biomolecular chemistry Vol.11 No.46

<P>Reaction between 1,2-bis(2-hydroxyphenyl)-ethylenediamine (<I>hpen</I>) and methyl pyruvate gives the diaza-Cope rearrangement product with good yield and excellent stereospecificity. The product containing two chiral quaternary carbon centers is characterized by high performance liquid chromatography and X-ray crystallography. DFT computation provides insight into why the diaza-Cope rearrangement takes place readily with methyl pyruvate but not with other ketones like acetone and substituted acetophenones.</P> <P>Graphic Abstract</P><P>Stereospecific diaza-Cope rearrangement of diimines formed between methyl pyruvate and hpen gives a twinned alanine with two quaternary chiral centers. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c3ob41582a'> </P>

On the Beginning of the English Alphabet

裵順稷(Soon-jik Bae) 새한영어영문학회 1980 새한영어영문학 Vol.9 No.-

胃腸管 肉腫에 關한 臨床的 考察

李舜稙(Soon Jik Lee) 대한외과학회 1978 Annals of Surgical Treatment and Research Vol.20 No.1