Tuning the Microstructure and Mechanical Properties of Cold Sprayed Equiatomic CoCrFeMnNi High-Entropy Alloy Coating Layer

Ji‑Eun Ahn,Young‑Kyun Kim,Sang‑Hoon Yoon,Kee‑Ahn Lee 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7

An equiatomic CoCrFeMnNi high entropy alloy (HEA) coating layer was prepared via a cold spray (CS) process. In orderto control the microstructure and nano-indentation properties of the CS HEA, heat treatments were employed. CS HEAcoating layer showed a heterogeneous microstructure where ultra-fine grains were formed at the particle interfaces, whilecoarse grains were formed inside the particles. Furthermore, deformation twins (DTs) were also formed inside the particlesdue to severe plastic deformation (SPD) in each particle generated during the CS deposition. For the 550 °C heat treatment(HT), fine Cr-rich precipitates were additionally formed at the grain boundary and particle boundary. By contrast, recrystallizationoccurred during 850 °C HT, while the size of the Cr-rich precipitate increased. The nano-indentation hardness ofthe CS HEA coating layer was 10.9 GPa, which was ~ 3 times higher than that of the conventional cast HEA. The superiorhardness of the CS HEA might has been enabled due to the combination of the high dislocation density, DTs, and ultra-finegrains. Based on the results above, the strategy to control the microstructure and mechanical properties through HT of theequiatomic CoCrFeMnNi HEA coating layer prepared via the CS process has been discussed.

여자체조 종목에서 국가 간 시작 점수(Start Valus)의 완성도

안애정,김윤지 韓國體育大學校 2002 論文集 Vol.25 No.-

To examine completion degree amongst gymnasts from different countries and bonus points acquired by the gymnasts from degree of difficulty based on flow of movements, this study compares gymnasts starting points and acquired points in four different competitions (the long horse, the parallel bars, the balance beam, the floor exercise) among the gymnasts from South Korea, China, Japan, and North Korea, who participated in the Busan Asian Games 2002. The results of this study are as follow: 1. North Korean gymnasts acquired high points in the long horse and the parallel bars, while Chinese gymnasts showed their strength in the balance beam and the floor exercise. Despite the relative higher points acquired in the balance beam and the floor exercise than North Korean gymnasts, South Korean team showed its weakness in long horse and the parallel bars. 2. In the bonus points acquired from flow of movement, Chinese team scored the highest while South Korean team scored the lowest. 3. In comparing the starting points and acquired points among the four competitions, little variations were shown among gymnasts from China Japan. However the variations were high among gymnasts from South and North Korea. 4. North Korean team showed a highest average score in the difference between starting points and acquired points in four competitions. A few suggestions can be made in order to improve the performance of Korean gymnasts based on the analysis of this study. The statistically low scores in bonus points acquired in flow of movements indicate that there is a room for improvements in developing new techniques and higher degree of difficulty movements. While South Korean gymnasts have equal capability in technical aspects in comparison with Japanese gymnasts, they showed higher degree of difference in starting points and final score. This difference indicates that more practice should be concentrated on mastering the movements to improve the degree of completion. With focused exercises and experiences gained from various International games, good performance by Korean gymnasts can be expected in the upcoming international events, as well as in the 2004 Olympics in Greece.

안결막에 감염된 동양안충 (Thelazia callipaeda)의 형태학적 소견

안영겸,양용강,조윤경,류장근,이지숙 THE KOREAN SOCIETY FOR BIOMEDICAL LABORATORY SCIEN 1997 Journal of biomedical laboratory sciences Vol.3 No.1

저자들은 1996년 7월에 강원도 춘천지역에서 농사업을 하는 60세 남자의 좌측 안결막에서 총 10마리의 유백색 선충을 적출하였다. 적출된 충체를 형태학적으로 관찰한 결과 Thelazia callipaeda Railliet et Henry, 1910으로 동정하였으며, 그 성적은 다음과 같다. 관찰된 유백색의 충체는 암놈 7마리, 숫놈 3마리였으며 충체의 크기는 암놈 11.91∼12.77×0.25∼0.26㎜, 숫놈 8.83∼9.32×0.24∼0.25㎜ 였다. 암놈과 숫놈의 구강 깊이는 각각 0.023∼0.026, 0.022∼0.023㎜이고, 충체전단에서 식도-장 접합부까지의 길이는 각각 0.58∼0.60, 0.56∼0.58㎜이었다. 표피소극의 배열은 전단부위에서 ㎜당 260∼290열이고 중앙부위에서 ㎜당 203∼207열 정도의 갯수가 관찰되었다. 그리고 암놈의 자궁내에는 coil상의 성숙된 유충이 관찰되었고 숫놈의 배설강구 전방의 유두수는 8쌍이었다. 이상과 같이 암수 충체에 대한 형태특징을 분석한 결과 Thelazia callipaeda로 동정되었다. The authors presented the human Thelaziasis case in Korea, with the review of the literatures. The patient was 60-year-old farmer who had lived in Chunchoun since birth. He complained lacrimation and foreign body sensation of the left eye. Total 10 worms, appeared to be slender milky-white nematodes, were extracted from the left upper conjuctival sac by authors. Micrograph morphological features are as follows: Three male worms are 8.83∼9.32㎜ in length, 0.24∼0.25㎜ in width, 259∼263 cuticular striations per mm, and showing cloaca with spicules. seven female worms are 11.91∼12.77㎜ in length, 0.25∼0.26㎜ in width, 259∼289 cuticular striations per mm, and vulva opening locating anterior to esophago-intestinal junction. From the above findings, these nematodes were confirmed as Thelazia callipaeda Railliet and Henry, 1910.

보육시설 교사를 대상으로 하는 환경교육 프로그램의 개발

안지연,윤재웅,안옥희 영남대학교 지역발전연구소 1999 새마을지역개발연구 Vol.25 No.-

It is very important for preschool child to environment education in child care and education institution. However only few studies concerned to concrete education program. Therefore this study was environment education program for teacher in child care and education institution. Environment education program were consist of four steps; general idea of environment education, component abstract of environment education program for child, give motivation with development to environment education program, application of environment education program.

아동 학대 및 방임

안동현,강지윤 大韓神經精神醫學會 2003 신경정신의학 Vol.42 No.1

Child abuse and neglect are also becoming a serious threat to the health of children in Korea. Most of abused or neglected children are suffered from some mental problems, Psychiatrists are a important position to evaluate and/or treat the emotional or behavioral problems resulting from child abuse or neglect, It is crucial that psychiatrists define their role and develop the appropriate clinical skills to manage child abuse or neglect effectively. This article reviews the clinically relevant literature on the child abuse and neglect including the strategic agenda of the Korean Medical Association for promoting of optimal child health and development comprehensively.

고감도 Ames test(microsuspension assay)와 임파구 소핵시험법을 이용한 변이원성에 관한 조사 연구

안지영,김해준,윤인재,성영자,김영환,장영철 大韓産業醫學會 1996 대한직업환경의학회지 Vol.8 No.3

In order to evaluate the mutagenic effects of extractable indoor air pollutants (organic matters), we measured the mutagenic activities by sensitive microsuspension Ames test using new tester strains (YG 1024 and YG 1029). And additionally to evaluate the mutagenic effects on vital cell, we examined the frequencies of micronucleus appearing in lymphocytes from dye handling workers and controls. This study was conducted from Jan. to May, 1995. The extractable indoor air pollutants were collected by low volume air sampler in a general office room and 3 of dye handling factories. And the environment of general office room divided into 3 different groups according to the type of room heaters. To determine the frequencies of micronucleus appearing in lymphocytes, we sampled peripheral venous blood from 20 of dye handling workers and 20 of controls, and cultured, and then examined the lymphocytes. The results obtained were as follows: 1. The indirect mutagenic activities of extractable organic matters from suspended particulates collected in a general office room were higher than the direct one. 2. The strain YG 1024 was the most sensitive, and the increasing order of test strains that showed higher number of revertant were YG 1024, YG 1029, TA 100, TA 98. 3. In the general office room, the room using kerosene heater showed the highest mutagenecity, and the next was buthan gas heater, and non-heating room in order. 4. The mutagenic effects of suspended particulates in dye handling factories on the strain YG 1024 was 1.2 times higher than YG 1029. 5. The frequencies of micronucleus appearing in lymphocyte of the circulating blood of dye handling workers and the control were 5.65±2.97‰ and 4.65±0.97‰, respectively. And the difference was statistically significant.

한국인에서 DXS7132 유전좌와 GATA31D10 유전좌의 다형성에 관한 연구

안종성,장영길,이숭덕,신창호,이윤성,이정빈 大韓法醫學會 2000 대한법의학회지 Vol.24 No.1

The validation study for two STR loci on X-chromosome, DXS7132 and GATA31D10, was done including allelic distribution and frequency of each allele to use these results for individual identification and paternity testing. For 496 unrelated Koreans, above two STR loci were amplified simultaneously using duplex PCR amplification method. The amplified products were analyzed by polyarylamide gel electrophoresis followed by silver staining. In male DXS7132 locus revealed 7 different alleles ranging from 276bp to 300bp. The largest allele was consisted of 14 repetition of [TCTA] unit and took 0.3417. The allele 15 followed next as 0.3165 and allele 13 as 0.1726. In female general distribution was same except one allele, allele 18 was found additionally. The heterozygosity was 0.7706 and 23 different genotypes were found. Polymorphism information content(PIC) was 0.727. Two cases of mutation were noted in DXS7132 locus In both male and femal 7 different alleles were noted in GATA31D10 locus and the alleles ranged from 195bp to 231bp. The allele 15(199bp) took the majority of all as 0.825. The other alleles showed rather relatively low frequency. The heterozygosity was 0.2385 and 11 different genotypes were found. PIC was 0.2521, and no mutation was noted in GATA31D10 locus. Considering these two loci together, 22 different halpotype were noted.

경북대 캠퍼스 내 대기환경 및 미규모 모델(MUKLIMO)을 이용한 바람장 모의 연구

민경덕,윤지원,안광득 한국환경과학회 2005 한국환경과학회지 Vol.14 No.3

Elements of atmospheric environment, temperature, humidity and wind, at the compus of KNU(Kyungpook National University) were investigated by the observations. The observed data were compared with those of DWS (Daegu Weather Station). The simulations of wind field and dispersions of polluted gases were conducted by MUKLIMO under the various conditions. The results show that the atmospheric environment of KNU are suitable but the campus does not play role as a heat sink in the city. The simulations of wind field show the air flows and wind channels in the campus clearly. The exhausted gases by motor vehicles on the northside street of campus affect very much to the campus with NW(300˚) wind. The running cars in the campus are also pollute much on the campus with the various wind directions. The characteristics of environmental conditions, various meteorological fields, wind channels, and dispersion of exhausted gases at the campus of KNU were understood quantitatively in the study.

치와와개에서 발생한 부신피질암종

이상설, 강지훈, 정윤경, 조현예, 한태성, 양만표, 장동우, 나기정, 김근형, 안병우 충북대학교 동물의학연구소 2006 Journal of Biomedical and Translational Research Vol.7 No.2

본문참고

말기신부전 환자에서 혈액투석 전후의 QT간격분산 비교

강대웅,정지용,윤나라,안치용,김종오,신병철,정종훈,김현리 朝鮮大學校 附設 醫學硏究所 2006 The Medical Journal of Chosun University Vol.31 No.2

Background: Some cases of QT interval, corrected QT interval (QTc), QT dispersion (QTd) and corrected QT dispersion (QTcd) have been reported in ESRD, but these results are variable and the influence of a hemodialysis is still controversial, In this study, we investigated the effect of hemodialysis on QT and QTc interval and QT and QTc dispersion in patients with ESRD 15 min before and 15 minute after each hemodialysis. Methods: Sixty-seven patients with ESRD (men 33 & women 34) on three-times stable hemodialysis (>3 months) were randomly enrolled. Fifty control subjects with a similar age and normal renal function were enrolled from this hospital. Routine biochemical studies were measured pre- and post dialysis, at the time of the ECG. Plasma Na+, K+, BUN, creatinine, ionized calcium and phosphate were checked. Twelve-lead electrocardiographs were performed at 10㎜/mv and 50㎜/s using a HewIett-Packard Pagewriter 100, before and after a single hemodialysis session.The QT interval was measured from the onset of the QRS complex to the end of the T wave. If the end of the T wave was not clear in a particular lead then it was excluded from analysis. When U waves were present, the end of the T wave was taken as the nadir between the T and U waves. Each QT interval was corrected for heart rate using Bazett's formula (QTc==QT/√(RR)) (ms). The difference between maximal and minimal QT interval duration was defined as QT dispersion (QTd) in each of the 12 leads. Result: This study demonstrates that QT, QTd, QTcd is higher in hemodialysis patients compared with control subjects, and QT and QTd rise postdialysis to levels comparable to those seen acutely following myocardial infarction, when patients are at greatly increased risk of potentially fatal ventricular arrhythmias, Conclusions: QT interval and QT dispersion, markers of risk for arrhythmias and sudden death, are elevated in hemodialysis patients, and rise postdialysis. QT interval and QT dispersion is an easily obtainable, noninvasive, simple, inexpensive, and widely available method of risk stratification in uremic patients receiving chronic dialysis. Additional studies are needed to clarity whether increased postdialysis QT dispersion results in an increased occurrence of arrhythmias.