Effects of Pilger Rolling and Heat Treatment on Microstructure and Corrosion Resistance of Ag-electroplated 304 Stainless Steel Tubes

Hyun Park,Woo‑Jin Lee,Jae‑Han Son,Han‑Kyun Shin,Sung‑Kyu Hong,Hyo‑Jong Lee 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

We introduce a cost-effective method that combines electroplating with metal cold working processes to manufacture compositetubes with robust corrosion resistance. First, a 3-step electroplating process was developed to form an adhesive anduniform Ag coating on the outer wall of a 304 stainless steel tube. The process consisted of a Ni-strike step for removing thepassivation layer of the initial 304 tube, Cu deposition for smoothing the surface by adding a buffer layer, and Ag deposition. To reinforce the interfacial adhesion between the electroplated layers and the 304 tube and increase the area of the Ag coating,a pilger rolling or pilger rolling + heat-treatment process was performed after the Ag electroplating process. Scanningelectron microscopy of the composite tubes after each process indicated that the as-deposited Ag coating changed fromhaving a rough to smooth surface after only pilger rolling and with additional heat treatment. Electron backscatter diffractionanalysis of the microstructures and textures of the tubes revealed that dynamic recrystallization occurred extensively duringpilger rolling, resulting in the formation of a relatively defect-free grain structure without heat treatment. Furthermore,electrochemical polarization curves determined that the Ag-coated composite tubes are superior to the uncoated 304 tubein terms of corrosion resistance under Cl−atmosphere, owing to the formation of a AgCl passivation layer during testing. Surface analysis of the composite tubes suggests that the properties of the AgCl passivation layer are related to the grainsize of the Ag coating and the density of plastic-deformation-induced defects.

한국 어린이에서 하악 유절치와 그 계승 영구치의 선천적 결손 간의 관계

김현진,현홍근,김정욱,이상훈,김종철,한세현,장기택 大韓小兒齒科學會 2010 大韓小兒齒科學會誌 Vol.37 No.1

많은 연구에서, 유치와 그 계승 영구치의 선천적 결손 간에는 상당한 연관관계가 있는 것을 보고하였다. 그러나 하악 전치부에서, 유치의 선천적 결손에도 불구하고, 그 계승 영구치는 정상적으로 존재하는 증례가 임상적으로 종종 관찰되기도 한다. 본 연구의 목적은 한국 어린이에서 하악 유절치와 그 계승 영구치의 선천적 결손 간의 상호 연관관계를 평가하는 데에 있다. 2005년 1월 1일부터 2008년 9월 5일까지 서울대학교치과병원에 내원하여 파노라마 방사선사진을 촬영한 6세 이하의 남녀 어린이 총 14,307명을 대상으로 하악 전치부의 치아양상을 관찰하여 유치와 영구치의 선천적 결손 관계를 평가하여 다음과 같은 결과를 얻었다. 1. 하악 유절치의 결손률은 0.24%였으며, 하악 유절치가 존재 시 후속 영구치가 존재할 승산(odds)은 7163.5였으며, 유절치의 결손 시 후속 영구절치가 존재할 승산(odds) 0.79였다. 2. 하악 유절치 결손의 증례 중 후속 영구치가 모두 존재하는 경우는 44.12%였다. 유절치의 양측 결손 시 후속 영구치가 하나라도 존재할 승산(odds)은 유절치 편측 결손 시에 비하여 1.57 배였다. 3. 유절치 결손이 있을 때 유절치의 편측 결손일 승산(odds)은 여자가 남자에 비해 2.2 배였다. 또한, 유절치 결손이 있을 때 후속 영구절치가 존재할 승산(odds)은 남자가 여자의 경우에 비하여 2.22 배였다. Many studies have shown that there is a strong relationship between the congenitally missing primary teeth and their succedaneous permanent teeth. However, especially in case of lower anterior region, we can observe the existence of permanent teeth even though their precedent primary teeth were missed at times. The purpose of this study was to reveal the relationship between the congenitally missing primary lower anterior teeth and their succedaneous permanent teeth in Korean children. Total of 14,307 children, under 6 years of age, who attended the department of pediatric dentistry, Seoul National University Dental Hospital, Seoul, Korea from January 1st 2005 to September 5th 2008 were radiologically examined using the panoramic x-ray in order to analyze the relationship between the congenitally missing primary lower anterior teeth and their succedaneous permanent teeth. The results were as follows : 1. The prevalence of congenitally missing lower anterior teeth in primary dentition was 0.24%. The odds ratio of both the primary and permanent anterior teeth being present was 7163.5 and only the permanent anterior teeth being present was 0.79. 2. The percentage of all succedaneous permanent teeth being present was 44.12% in cases of missing lower primary anteriors. The odds ratio of at least one succedaneous permanent teeth being present in cases of bilateral primary anterior teeth missing was 1.57 times more common than in cases of unilateral primary teeth missing. 3. The odds ratio of primary missing teeth being unilateral was 2.2 times higher in females. Moreover, the odds ratio of succedaneous permanent teeth being present in cases of primary teeth missing was 2.22 times higher in males.

논문 : 1920년대 초기 『조선일보』 「문예란」 연구 -발굴과 위상의 구명

박현수 ( Hyun Soo Park ),홍현영 ( Hyun Young Hong ) 민족문학사학회·민족문학사연구소 2015 민족문학사연구 Vol.57 No.-

『조선일보』의 「문예란」은 1921년 7월 4일부터 같은 해 8월 27일까지 『조선일보』1면에 개설되었다. 이 글의 목적은 『조선일보』 「문예란」에 실린 작품들을 발굴, 소개하고, 그 위상을 구명하는 것이다. 「문예란」이 개설되었던 때는 『조선일보』가 23회에 이르는 발매반포금지와 2차례의 정간을 겪고 점차 운영에서 정상을 찾아가던 즈음이었다. 「문예란」은 총 38회 개설되었는데, 시가 21편, 평론이 3편, 기행문이 1편, 수필이 1편 등 모두 26편의 작품이 실렸다. 「문예란」에 글을 수록한 작가는 변영로, 남궁벽, 김억, 박종화, 오상순, 오천석, 김찬영, 현진건 등이다. 변영로는 「문예란」에서 가장 활발한 작품 활동을 했으며 필자들의 교류에서도 중심에 있었다. 그는 진리가 확정된 세계에서 벗어나 불확실성에 투신하는 자세를 새롭게 창출될 문학의 핵심이라고 주장했다. 이 글은 남궁벽이 스스로 ``∼다``체로 번역해 발표한 「별의압흠」, 「말」 등을 소개하는 것을 통해 정본 확정의 문제를 제기했다. 또 작가의 과작을 고려할 때 새롭게 발굴, 소개하는 남궁벽의 시 5편이 지니는 무게 역시 가볍지 않다. 박종화의 시 가운데 「廢園에누어셔」는 「黑房秘曲」에 실린 시와 달리 3장으로 되어 있다. 특히 3장이 당시 박종화의 지우였던 정백, 홍사용 등의 갈등과 관련되어 주목을 필요로 한다. 이 글에서 소개하는 오상순의 두 시 역시 처음 발굴, 소개하는 시들이다. 이들은 어린 시절의 상상력이 깃든 언어를 가장 본질적인 것으로 파악하는 당시 오상순의 문학관을 드러내고 있다. 「문예란」의 필자들은 이미 문단의 승인을 받은 존재들이었다는 점에서 작품들 역시 문학청년 시기의 습작이나 투고작과는 다르다. 또 「문예란」의 필자는 각각의 동인지에 얽매이지 않는 문인들의 네트워크와 문학 활동을 파악할 수 있는 대상이기도 하다. 「문예란」이 지닌 가장 두드러진 의미는 『조선일보』를 비롯해 『동아일보』 『매일일보』 등 당시 신문 미디어에 같은 성격의 지면이 존재하지 않았다는 점에 있다. Literary section in Chosun Ilbo was first open on July 4, 1921 and lasted until on August 27 in the same year. The section was reported on the first page of Chosun Ilbo. The purpose of this article was to discover and introduce the pieces of literary work reported in Chosun Ilbo, and to bring light on the status of its literary section. The time when literary section was established was the moment Chosun Ilbo was returning to normal condition of running business after having twenty three times of prohibition of release and two times of suspension. The number of reported literary section was thirty eight, which included twenty one pieces of poem, three pieces of critique, one piece of travel essay, and one piece of essay. Thus, the total number of reported literary work was twenty six. Writers who participated in the section were as followed : Young-Roh Byun, Byuk Namgung, Uk Kim, Jong-Hwa Park, Sang-Soon Oh, Chun-Seok Oh, Chan-Young Kim and Jin-Gun Hyun. Among them, Young-Roh Byun was the most active writer in the literary section and was in the center of mutual exchange of opinion among the writers. He sought the core of literature in the attitude that was devoted to the uncertainty, which was off the world of concrete truth. This article supposed a question on determination of the formal copies by discovering and introducing the Byul-eui-ap-hem(별의압흠), and Mal(말) which were reported by Byuk. He translated these pieces for himself using style of writing, "∼ da". Moreover, as Namgung was not a prolific writer, the importance of five pieces of poem by Byuk Namgung should not be overlooked. Park`s poem, Lying in the closed garden(廢 園에누어셔), consisted of three chapters compared to that of his, which were issued in Secret songs in a black room(黑房秘曲). Especially, the third chapter of it was related to conflict among his companions, Baek Jung and Sah-Yong Hong. Therefore, it needs to be focused on that chapter. Two pieces of poem by Sang-Soon Oh were introduced for the first time. These represented Oh`s literary view at the moment, which the writer understood the language with childhood imagination as the most essential one. Writers of the literary section had already been approve by the literary circle. For this reason, the pieces reported in the literary section had a different character from their studies or submission before starting their literature career. In addition, the writers were the subject of the network and career activities among the writers who were not bound by literary coterie magazines. The most significant meaning of literary section was that the section with the same character did not exist in Dong-A Ilbo, Maeil Shinbo, or Chosun Ilbo itself. To prove this point, relation between news media and literature in early 1920s was discussed.

제주해협의 해류와 월별 유량변화

노홍길,방익찬,김상현,현경훈,김준택,양영진,홍창수 제주대학교 해양연구소 1997 해양자원연구소연구보고 Vol.21 No.-

Currents are measured in the Straits of Cheju by detecting surface buoy tracks and mooring current meters in 1996-1997. As a result, north-eastward currents are decteted in the Straits of Cheju all the year round, which is weak in spring and strong in summer and fall. Average speeds of 20 cm/s to the east. 7 cm/s to the north and 22 cm/s to the north-east appeared in the surface. Currents are fast in the middle of the strait and slow near Cheju Island. East-west components of the currents are about 3 times faster than the north-south ones. Also. it is shown that surface buoys released within the distance of 6 miles away from Cheju do not drift out of the Straits of Cheju because of tongue-like warm waters appeared in the eastern entrance of the strait. Volume transports calculated by geostrophic calculation are shown to be 0.05-0.2 Sv in winter and 0.4-0.5 Sv in summer.

심실 중격 결손에 의한 감염성 심내막염 환자의 치과치료

양정현,현홍근,김영재,김정욱,장기택,이상훈,한세현,김종철 대한소아치과학회 2007 大韓小兒齒科學會誌 Vol.34 No.3

농촌지역 노인들의 우울증상에 관련된 요인들의 특성

송미숙,전기홍,송현종,김정은,박승구,신상건,이동훈,정성현,최연주,최완철,최민규,황재철,홍지만 아주대학교 1997 아주의학 Vol.2 No.2

This study was performed to identify risk factors for depression among the elderly in a rural area. A survey was done for the elderly living in Gosam-myenn, Ansung-kun during the period of July 28, 1997 and July 30, 1997. Demographic and sodoeconornic characteristics, and functional and health Status were assessed using a structured questionnaire, and the level of depression was measured by GDS score. The data obtained were analyzed by frequencies, percentage, t-test, ANOVA, and multiple regression, and the results were as follows: 1. The total sample consisted of 133 elderly. Of them, 47 elderly (35.4%) showed significant depressive Symptoms. 2. The GDS score was the highest for the group over 85 years of age (p < 0.05). Those living alone or widowed showed lower GDS score than those living with someone or married (p < 0.05). 3. The GDS score was the highest in the absolutely dependent group, followed by the partially dependent group, and the independent group (p < 0.01). The elderly who perceived their health Status as excellent showed the lowest GDS score. In contrast, those who had more than five chronic diseases showed the highest GDS score. 4. The elderly receiving financial and emotional support from their family or friends showed lower GDS score compared to those without any support. 5. The economically dependent group showed higher GDS score than that of independent group. 6. The elderly who involved in leisure activities showed lower GDS score than those without any involvement. 7. In terms of risk factors for depression, we found that perceived health Status, subjective economic Status, leisure activities, living arrangement and financial support were inversely associated with GDS score, whereas labor support was positively associated with GDS score. Based upon the above findings, this study suggests that these risk factors for depression in the elderly should be taken into consideration for a comprehensive mental health program for the elderly living in the rural area.

연령에 따른 한국인 손 피부색 차이 분석

홍다검ㆍ이희경ㆍ이정현(Da Geom HongㆍHee kyung LeeㆍJeong Hyun Lee) 한국인체미용예술학회 2016 한국인체미용예술학회지 Vol.17 No.1

Recently, nail industry trends have been shifting from polish nail to gel nail. Because of the popularity of gel nail, the criteria for customers to choose colors have significantly changed. Therefore, there has been a rising demand for a nail color which goes well with skin color, not with the color of clothes, makes the hand more beautiful. Unlike a face, hand skin color isn’t corrected through makeup. Therefore, it is more difficult to find a color which is well matched with the skin tone. In this sense, the accurate analysis and classification of hand skin color which is the first step in the selection of nail color are required. However, it’s still very hard to find studies on hand skin color. To figure out the characteristics of Koreans’ hand skin color by age, this study analyzed differences in hand skin color by age after measuring the tone of the back of the hand and conducting quantitative analysis against 300 women living in Busan, Ulsan and Gyeongnam. The results revealed statistically significant difference (p.001). As the respondents were younger, a bright skin tone was observed. According to analysis on the distribution by the rank, ‘20s’ was the highest with 46% among those with a bright skin tone within top 100 ranks. In top 300 ranks, in contrast, ‘50s’ was the highest with 46% while ‘20s (8%)’ was the lowest. In terms of a skin tone, there was a considerable difference between ‘20s’ and ‘50s.’ Even though no big difference was found between ‘30s’ and ‘40s,’ a skin tone was brighter in the latter.

김치에서 분리한 Lactobacillus sp. JC-7과 Lactobacillus acidophilus 88간의 Electrofusion 최적조건 설정

조영배,최현정,백형석,전홍기 부산대학교 유전공학연구소 1997 분자생물학 연구보 Vol.13 No.-

김치 발효 숙성기간을 연장하고 신선도를 오랫동안 유지 할 수 있는 김치발효 starter의 개발을 목적으로 최적숙성기에 있는 김치로부터 bacteriocin생성능이 없는 유산균을 분리하여 동정하였으며, bacteriocin생성능이 우수한 L.acidophilus 88을 융합시키기 위해 electrofusion에 대한 최적 조건을 검토하였다. 분리균주는 Lactobacillus속으로 동정되어 Lactobacillus sp. JC-7이라 명명하였다. Electrofusion에 의해 생성된 융합주를 식별하기 위해 streptomycin(2.5㎎/ml)에 내성을 나타내는 Lactobacillus sp. JC-7변이주와 kanamycin(600㎍/ml)에 내성을 나타내는 L.acidophilus 88변이주를 분리하였다. Electrofusion을 100V/㎝, 120msec(72ohms,1670 capacitance) 에서 수행했을 때 융합효율이 가장 양호하였으며 전기장의 세기와 시간이 중가할수록 융합 효율이 현저히 감소하였다. 2가 양이온은 농도가 중가할수록 대체적으로 융합효율을 감소시키는 경향을 나타내었으나 1mM MGCl_2에서는 대조군에 비해 융합효율이 약간 증가하였다. PEG매개에 의한 융합법의 융합효율을 비교한 결과, 융합효율은 chemical fusion<electrofusion<electrofusion+20% PEG순을 나타내었다. Evaluation of Optimum Conditions for the Electrofusion between Lactobacillus sp. JC-7 Isolated from Kimchi and Lactobacillus acidophilus 88. Young-Bae Jo, Hyun-Jung Choi, Hyung-Suk Baik and Hong-Ki Jun*. Department of Microbiology, Pusan National University, Pusan 609-735,Korea-A lactic acid bacterium was isolated from kimchi. The isolated strain was identified as the genus Lactobacillus thrugh its morphological characteristics and named as Lactobacillus sp. JC-7. The optimum conditions for the electrofusion between streptomycin(2.5㎎/ml)resistant mutant of Lactobacillus acidophilus 88 and kanamycin(600㎍/ml) resistant mutant Lactobacillus sp. JC-7 were evaluated. The highest number of fusants were obtained at a capacitance value of 120msec(1670㎌), a field strength of 100V/㎝,and a pulse controller setting of 72Ω. The potimum pH of elecroporation buffer was 7.5 and the concentration of divalent cation was 1mM MG^2+. Electrofusants were efficiently obtained by addition 20% polyethylene glycol to electroporation buffer. The yield of fusion was better than that of using polyethylene glycol mediated chemical induction.

음식물류폐기물 공공 자원화시설 운영에 관한 연구 (Ⅱ)

홍용표ㆍ김웅용ㆍ신현곤(Yong Pyo HongㆍUng Yong KimㆍHyun Gon Shin) 유기성자원학회 2016 유기물자원화 Vol.24 No.1

본 연구는 음식물류폐기물 공공 자원화 시설 운영의 문제점과 제도 개선방안을 위하여 실시하였다. 현재 운영중인 음식물류 폐기물의 가동율 현황과 자원화 시설의 확충 계획에 대한 분석을 통해 시설의 무분별한 신규건설로 인한 국가의 예산이 낭비되지 않도록 그 대안을 제시하였으며, 그 결과는 다음과 같다. 공공 자원화시설 신규 확충보다는 기존 민간 자원화시설을 활용하여 예산을 절약하고 음식물류 폐기물의 안정적인 처리는 물론 자원순환을 촉진시킬 수 있는 정책전환이 필요하다. 음식물류 폐기물을 친환경적인 방법으로 안정적으로 처리하기 위해서는 제도개선이 필요하며, 이를 위해 민간 자원화시설 가동률 저하를 줄일 수 있는 준공영제 도입이 필요하다. 또한, 공공 자원화시설의 검증된 기술과 경제성 확보 방안 마련이 필요하다. This study is conducted to find out the problems of the public food waste recycling facility operation and its improvement. In order to save the national budget by analyzing plans to expand including operation rate for the food waste recycling facility, the alternative ways are suggested. The result can be as follows: Policy switch is required not only to save budget and stable disposal of food waste but also to promote resource recycling rather than expanding public facilities. In order to change the policy for stable and eco-friendly disposal of food waste, it is necessary to adopt semipublic system that prevent the decline of the rate of operation of private resource recycling facility. Furthermore, it is required to prepare both qualified technologies of public resource recycling and the ways of profitability secure.

Floristic characteristics of vascular plants and first distributional report of Pseudostellaria baekdusanensis M. Kim in Yongneup wetland protected area

Young-Chul Kim,Hyun-Hee Chae,Sang-Heock Oh,Seung-Ho Choi2,Moon-Pyo Hong3,Gi-Heum Nam,Jae-Yoon Choi,Hyun-Sook Choi,Kyu-Song Lee 한국환경생태학회 2015 한국환경생태학회지 Vol.29 No.2

Yongneup wetland protected area, the only high moor in Korea, is a core area to conserve biodiversity. Even though the Yongneup wetland protected area is relatively small, various plant species are distributed in the Yongneup wetland protected area because it includes various habitats showing different environmental gradients. Vascular plants distributed in the Yongneup wetland protected area were identified as a total of 376 taxa that is composed of 73 families, 217 genera, 322 species, 3 subspecies, 44 varieties and 7 forms. For endangered plants designated by the Ministry of Environment, 5 species including Trientalis europaea var. arctica, Lilium dauricum, Halenia corniculata, Lychnis wilfordii and Menyanthes trifoliata were found and 34 taxa were confirmed to be distributed only in the mountainous wetland habitats. Regarding naturalized plants, a total of 11 taxa were distributed, but most of them were distributed in the areas where artificial interference has occurred. And in areas inside the wetlands that are relatively well preserved, 2 species of Bidens frondosa and Erigeron annuus were observed. In this study, the occurrence and distribution of Pseudostellaria baekdusanensis M. Kim, which was recently found in Mt. Baekdu and reported as a new species, were identified in the Yongneup wetland protected area. A wetland is a very vulnerable area to drastic environmental changes and damages to its ecosystem could cause the extinction of rare plant species which are distributed only in the wetlands. Therefore, it is mandatory that current status of the Yongneup wetland protected area is evaluated and actions to prevent rapid environmental changes are taken. Fourteen separate investigations were conducted in 2013 and another four in 2014, to evaluate current status of the Yongneup wetland protected area. These investigations have provided us the basic information for future actions of conservation and restoration.