GMA용접에서 콘택트 팁 재질에 따른 용접특성 평가

김동윤,황인성,김동철,강문진,Kim, Dong Yoon,Hwang, In Sung,Kim, Dong Cheol,Kang, Moon Jin 대한용접접합학회 2014 대한용접·접합학회지 Vol.32 No.6

The contact tip for gas metal arc welding has important functions to transmit the welding current to the wire and to guide the wire to molten pool. If the contact tip is damaged, it is a cause of lowering the welding productivity due to removal of welding defects and replacement of contact tip. In case of the use of a contact tip for a long time the arc is unstable because the processed hole in the contact tip center is larger, and the variation of aiming position of the welding wire causes a seam tracking error. In this study, gas metal arc welding experiments using contact tip of three different materials were performed. The contact tips with Cu-P, Cu-Cr, and Cu-ODS were used at the experiments, and the welding characteristics by each contact tip were evaluated. After welding contact tip appearance, welding spatter adhesion amount of the nozzle, and weld bead appearance were evaluated. The welding current and welding voltage were measured to verify arc stability during arc welding.

부분결합간섭계에 내장된 인공수정체 도수측정 공식들의 정확성 비교

김동윤,김명준,김재용,차흥원,Dong Yoon Kim,MD,Myoung Joon Kim,MD,PhD,Jae Yong Kim,MD,PhD,Hungwon Tchah,MD,PhD 대한안과학회 2009 대한안과학회지 Vol.50 No.4

Purpose: To evaluate the accuracy of various formulas installed in IOLMaster software which uses partial coherence interferometry for axial length measurement. Methods: This retrospective comparative study included 81 eyes of consecutive patients who had uneventful cataract surgery with implantation of Acrysof single piece (SA60AT) IOL. Axial length was measured with IOLMaster and IOL power was calculated using various formulas, including SRK II, SRK/T, Holladay 1, Haigis, and Hoffer Q. Subjects were stratified by axial length into Groups A (axial length < 23.50 mm), B (23.50 mm ≤ axial length < 25.00 mm), and C (axial length ≥ 25.00 mm). Target refractions of the five formulas were compared to the postoperative manifest refraction at 1 month. Results: The five formulas showed no difference in predicting postoperative refractive errors among all of the groups. Conclusions: Five formulas installed in IOLMaster software provided equivalent predictions of postoperative refractive error regardless of axial length. J Korean Ophthalmol Soc 2009;50(4):523-528

마이토마이신을 이용한 라섹 수술 후 지연성으로 발생한 비대 각막 반흔 2예

김동윤,김명준,윤삼영,신철진,김경훈,차흥원,Dong Yoon Kim,MD,Myoung Joon Kim,MD,PhD,Sam Young Yoon,MD,Chul Jin Shin,MD,Kyoung Hoon Kim,MD,Hungwon Tchah,MD,PhD 대한안과학회 2009 대한안과학회지 Vol.50 No.2

Purpose: To report late-onset hypertrophic corneal scars after laser epithelial keratomileusis (LASEK) with mitomycin C. Case summary: Case 1. A 34-year-old man who had undergone LASEK with mitomycin C 15 months prior was referred to our clinic because of corneal opacity of his right eye. After LASEK, there have been no abnormalities in either of his eyes. However, 11 monthsafter LASEK, he experienced decreased visual acuity in his right eye. The visual acuity was 0.03 in his right eye and 1.0 in his left eye. On slit lamp examination there was a whitish, hypertrophic scarin his right cornea. The lesion was located in the corneal center and the subepithelial space. Central corneal thickness was 828 μm. Case 2. A 23-year-old woman who had undergone LASEK with mitomycin C 14 months before was referred our clinic because of corneal opacity of her left eye. After LASEK, there had been no abnormalities in either of her eyes. However, 12 months after LASEK she experienced decreased visual acuity in her left eye. The visual acuity was 1.0 in her right eye and 0.2 in her left eye. On slit lamp examination there was a whitish, hypertrophic scar in her left cornea. Central corneal thickness was 794 μm. Conclusions: Manual debridement was performed to remove the hypertrophic scar in both cases. Case 1. After manual debridement, visual acuity of the right eye improved to 0.63. Case 2. After manual debridement, best-corrected visual acuity of the left eye was 0.63.

플럭스 코어드 와이어에 따른 용접 중 콘택트 팁 내마모성 평가

김동윤,황인성,김동철,강문진,Kim, Dong-Yoon,Hwang, In-Sung,Kim, Dong-Cheol,Kang, Moon-Jin 대한용접접합학회 2013 대한용접·접합학회지 Vol.31 No.4

The contact tip for flux cored arc welding has important functions to transmit the welding current to the wire and to guide the wire to molten pool. A damaged contact tip causes a productivity reduction and a welding quality problem. In this study, the welding experiments for the wear resistance of contact tip regarding flux cored wire types were performed. With two fold type and a seamless type flux cored wires, the wear rates of contact tips were compared. In addition, the wear rate was checked according to the contact tip position.

시편 예열 온도가 FCW 용착금속의 확산성 수소량에 미치는 영향

김동윤,황인성,김동철,강문진,Kim, Dong Yoon,Hwang, In Sung,Kim, Dong Cheol,Kang, Moon Jin 대한용접접합학회 2014 대한용접·접합학회지 Vol.32 No.2

Cold cracking of weldment is one of the most serious welding problems. A sufficient quantity of diffusible hydrogen, a residual stress, and a sensitive microstructure are the causes of cold cracking. Removal of any one of these factors can be used to prevent cold cracking. Application of flux cored arc welding process is increasing due to high productivity and easiness of welding. In addition, to prevent cold cracking in the HAZ or weldment, preheat temperature and interpass temperature have to be controlled. In this study, the effect of preheat temperature on the levels of diffusible hydrogen in the weld metal deposited using flux cored wire was examined. The levels of preheat temperature of base metal specimen were ambient temperature, 50, 100 and $150^{\circ}C$ respectively. The result showed that the increase of preheat temperature was a linear relationship with reduction of diffusible hydrogen content in weldment.

마을 만들기 연구의 정량적 접근에 관한 소고 - 마을 만들기 사업규모와 성과의 관계를 중심으로 -

김동윤,김선직,강래천,Kim, Dong-Yoon,Kim, Sun-Jick,Kang, Rae-Cheon 한국디지털건축·인테리어학회 2011 한국디지털건축인테리어학회 논문집 Vol.11 No.2

Skeptical responses to urban design based on the Physical Planning theory assuming the existence of social agreement and the absolute authorities of planners bring about alternatives such as Participatory Planning and Community Design derived from Harbermas' Communicative Rationality. But the normative contentions do not progress any more to the stage of presenting practical strategies. This is the cause why there should be systematic approaches to reveal the relationships among various concepts or variables. With regard to the Community Design this study intends to take a statistical approach to find relationship between project scale and its accomplishment. The hypothesis that the smaller scale of project begets the better outcomes was tested to be rejected as a result of the analysis of variance. But the result also shows that appropriate density in relatively large area makes residents' expected satisfaction high. Although this discovery has its own meaning the tryout is anticipated to laying the cornerstone of quantitative analyses in the following studies.

원격 스캐너를 이용한 알루미늄 레이저 용접에 대한 생산 공정 최적화 설계

김동윤,박영환,Kim, Dong-Yoon,Park, Young-Whan 대한용접접합학회 2011 대한용접·접합학회지 Vol.29 No.6

In this study, we conducted laser welding by using remote scanner that is 5J32 aluminum alloy to observe the mechanical properties and optimize welding process parameters. As the control factors, laser incident angle, laser power and welding speed were set and as the result of weldablility, tensile shear tests were performed. ANOVA (Analysis of Variation) was also carried out to identify the influence of process variables on tensile shear strength. Strength estimation models were suggested using regression alnalysis and 2nd order polynomial model had the best estimation performance. In addition optimal welding condition was determined in terms with wedalility and productivity using objective function and fitness function. Final optimized welding condition was laser power was 4 kW, and welding speed was 4.6 m/min.

정치참여 수단으로서 댓글의 역할과 의미, 그리고 한계

김동윤(Dong Yoon Kim),홍하은(Ha Eun Hong) 사이버커뮤니케이션학회 2015 사이버 커뮤니케이션 학보 Vol.32 No.1

이 연구는 온라인 뉴스와 SNS 뉴스 이용자 간 비교를 통해서 정치참여 수단으로서 댓글의 역할과 의미를 알아보고자 한 것이다. 이를 위해, 댓글 저널리즘의 원형으로 이해되는 온라인 뉴스와 댓글의 새로운 지평을 열고 있는 SNS 뉴스의 댓글에 대한 이용자의 인식과 활동의 차이를 알아보고, 이러한 인식과 활동이 정치참여에 미치는 영향을 실증적으로 비교해 보았다. 분석의 결과는 다음의 몇 가지로 요약할 수 있다. 먼저, 이용자들은 SNS 뉴스보다 온라인 뉴스의 댓글을 더 신뢰하고, 유용한 것으로 인식하고 있었다. 다음으로, 온라인 뉴스와 SNS 뉴스 이용자의 댓글 읽기 활동에 대한 통계적 차이는 발견되지 않았으나, 쓰기 활동에서는 온라인 뉴스 이용자들이 더욱 적극적인 것으로 나타났다. 마지막으로, 온라인 뉴스와 SNS 뉴스 댓글에 대한 이용자들의 이러한 인식과 활동이 그들의 정치참여에는 긍정적인 영향을 미치지 않는 것으로 나타났다. 다만, 댓글 이용자의 정치참여는 정치에 대한 평소의 관심과 대화량에 의해 더욱 잘 예측되었다. 선거 시기 정치참여 수단으로서 보여준 지금까지의 역할과 의미를 감안할 때, 이상의 분석 결과는 정치참여 수단으로서 댓글의 역할과 의미는 비선거 시기라는 상황과 맥락에서 다소 제한적일 수 있음을 시사해 주었다. This empirical study has tried to see the difference of the meanings and roles of the reply as the instrument of the political participation through comparing with the users of the online and SNS news users. Analytic results can be summarized as followings. First, users regarded the online news reply as more reliable and useful means than the SNS news reply. Second, there was no statistical difference in the reading activity between the online and SNS news users, but the online news users seemed to more active than the SNS news user in their writing. Third, the recognitions and activities of the online and SNS news users didn’t have the statistical effects on the predicting to their political participation, but their political participation was well predicted by the ordinary political concerns and conversation. These results made us infer that the meanings and roles of the reply as the instrument of the political participation might be varied and limited in terms of the situations and/or contexts, especially whether their interactions occur in election period or not.

▣ 일반 논문 : 지오노의 소설 『안젤로』(Angelo)에 나타난 인물 연구

김동윤 ( Dong Yoon Kim ) 성균관대학교 인문학연구원(성균관대학교 인문과학연구소) 2016 人文科學 Vol.0 No.60

본 논문은 장 지오노의 소설 『안젤로』에 나타난 주요인물과 로마네스크적 구성에 관한 글이다. 소설 『안젤로』는 작가의 생애에 있어서 이정표가 되는 작품이다. 지오노가 이 소설을 작성하던 시절은 프랑스가 나찌 독일로부터 해방된 시기와 맞물리고 있으며 그 당시 작가는 오해와모함으로 그의 작품이 출판금지 당하는 등 많은 고초를 겪었다. 소설 『안젤로』는 이른바 작가의 ``기병시리즈``의 첫 작품으로서 『지붕위의 기병』에 비해 잘 알려지지 않았으나 새로운 인물의 창조와 서사적완결성이 돋보이는 수작으로 평가된다. 가령, 본 작품에 등장하는 안젤로는 『지붕위의 기병』의 주인공, 그리고 셀린 드 테위스, 폴린은 이후작품들에 등장하는 주요 인물들에 원형을 제공한다는 점에서 연구의 대상이 된다. 따라서 본 글에서는 안젤로, 폴린 등 주요 인물들의 성격과작품의 윤리적 정조(情調)와 미학의 다층적인 국면들을 분석할 것이다. 그러한 맥락에서 안젤로, 폴린, 셀린 드 테위스와 같은 주요 인물들이구성되는 방식과 그들의 윤리관을 분석하는 일은 지오노 문학이 전환점을 맞이하는 국면들을 검토하는데 중요한 작업이 될 것이다. 우선 주인공은 중세 기사도 정신을 계승하고 위대한 정신과 순수한 영혼을 지닌 인물이다. ``검은 말을 탄 금 이삭``으로 묘사되는 안젤로는 이탈리아 기병이자 공작부인 에지아의 아들로서 귀족적인 기품을 지니고있으며, 자유가 결핍되어 있는 자신의 조국을 구하기 위해 싸우는 인간이다. 본 소설에는 안젤로와 함께 셀린 드 테위스와 폴린과 같은 흥미로운여성 캐릭터가 등장한다. 안젤로의 정신적인 후원자인 셀린 드 테위스는무르익은 원숙함과 함께 지혜롭고 매력적인 모습을 보여주는 인물이다. 이에 비해 폴린은 셀린 드 테위스의 오빠인 로랑 드 데위스의 젊은 부인으로서 순수하고 단순한 마음을 지닌 인물로 묘사된다. 두 여성 캐릭터의 등장으로 인해 자칫 단순하고 메마른 모험담으로 전개될 수 있는 서사가 로마네스크적인 요소를 획득함으로써, 본 작품은보다 흥미롭고 풍요로와진다. This study aims to analyze how main characters in Giono`s novel Angelo are created and constituted essentially from the ethical and aesthetical perspective. It is commonly accepted among many experts of this French novelist that this literary work played a important role in his literary career. The fictional work in question is supposed to be less known in the pubic audience in comparison with the other major works like The Horseman on the Roof of which a well known film was made two decades ago. However this novel seems to be of an importance in terms of prefiguring main characters (essentially Angelo and Pauline) constantly appearing in the following major works. Firstly, Angelo appears as a key character embodying the middle age`s chivalrous values like magnanimity, greatness, noblesse etc. These ethical aspects seem to be taken by and large in the French classical dramas, especially Pierre Corneille`s ones. In this context we would like to highlight that Angelo is being inscribed in this aristocratic moral system as well as in Romantic sensibility. Secondly, two feminine figures showing exceptional qualities (Celine and Pauline) are contributing greatly to the promotion of Giono`s work into a much more achieved one from the aesthetical perspective of the fiction: Celine de Theus is an aristocratic and highly mature personality with a strong sense of honour, while Pauline is presented as a young and pure person valorizing a great sense of simplicity. Thanks to these feminine figures with Angelo, the provencal novelist could create an extraordinary fictional universe in which we the readers can be easily absorbed without any reserves.

장 지오노 문학에 나타난 행복의 모럴과 생태적 사유에 관한 연구 - 『진정한 부Les vraies richesses』를 중심으로

김동윤(KIM Dong-Yoon) 프랑스학회 2005 프랑스학연구 Vol.32 No.-