Evaluating Corrosion Resistance of Additive-Manufactured Ti–6Al–4V Using Electrochemical Critical Localized Corrosion Temperature

Jae‑Bong Lee,Dong‑il Seo,Hyun Young Chang 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.1

A new concept to evaluate the localized corrosion resistance of stacked Ti alloys such as additive-manufactured (AM)Ti–6Al–4V alloy is proposed. Crevice corrosion of subtractive-manufactured (SM) Ti–6Al–4V occurred on the surfacebeneath the crevice former, whereas localized corrosion of the AM alloy occurred in any vulnerable site irrespective of thecrevice assembly. The electrochemical critical localized corrosion temperature (E-CLCT) was measured to evaluate theresistance of AM Ti–6Al–4V alloys to localized corrosion. The results showed that the localized corrosion of AM Ti–6Al–4V was attributable to the anisotropy and microstructure that resulted from rapid cooling, which were completely differentfrom the anisotropy and microstructure of SM Ti–6Al–4V. The optimum applied potential of AM Ti–6Al–4V in 25 wt%NaCl aqueous solution was deduced. The E-CLCT provides a useful criterion for determining the resistance of AM Ti alloysto localized corrosion and for comparing their resistances.

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.

Changes in αB-crystallin, tubulin, and MHC isoforms by hindlimb unloading show different expression patterns in various hindlimb muscles

( Hyun Seok Jee ),( Taka Shi Skurai ),( Jae Young Lim ),( Hideo Hatta ) 한국운동영양학회 2014 Physical Activity and Nutrition (Phys Act Nutr) Vol.18 No.2

Hyun Seok Jee, Takashi Sakurai, Jae-Young Lim and Hideo Hatta. Changes in αB-crystallin, tubulin, and MHC isoforms by hindlimbunloading show different expression patterns in various hindlimb muscles. JENB., Vol. 18, No. 2, pp.161-168, 2014 [Purpose]αB-crystallin is a small heat shock protein that acts as a molecular chaperone under various stress conditions. Microtubules, whichconsist of tubulin, are related to maintain the intracellular organelles and cellular morphology. These two proteins have been shownto be related to the properties of different types of myofibers based on their contractile properties. The response of these proteinsduring muscular atrophy, which induces a myofibril component change, is not clearly understood. [Methods] We performed 15days of hindlimb unloading on rats to investigate the transitions of these proteins by analyzing their absolute quantities. Proteincontents were analyzed in the soleus, plantaris, and gastrocnemius muscles of the unloading and control groups (N = 6). [Results]All three muscles were significantly atrophied by hindlimb unloading (P < 0.01): soleus (47.5%), plantaris (16.3%), and gastrocnemius(21.3%) compared to each control group. αB-crystallin was significantly reduced in all three examined unloaded hindlimb musclescompared to controls (P < 0.01) during the transition of the myosin heavy chain to fast twitch muscles. α-Tubulin responded onlyin the unloaded soleus muscle. Muscle atrophy induced the reduction of αB-crystallin and α-tubulin expressions in plantar flexormuscles with a shift to the fast muscle fiber compared to the control. [Conclusion] The novel finding of this study is that bothproteins, αB-crystallin and α-tubulin, were downregulated in slow muscles (P < 0.01); However, α-tubulin was not significantly reduced compared to the control in fast muscles (P < 0.01). [Keyword] Microtubule, αB-crystallin, tubulin, myosin heavy chainisoform, skeletal muscle

Ganglioside GM1 influences the proliferation rate of mouse induced pluripotent stem cells

( Jae-sung Ryu ),( Kyu-tae Chang ),( Ju-taek Lee ),( Malg-um Lim ),( Hyun-ki Min ),( Yoon-ju Na ),( Su-bin Lee ),( Gislain Moussavou ),( Sun-uk Kim ),( Ji-su Kim ),( Kinarm Ko ),( Kisung Ko ),( Kyung- 생화학분자생물학회(구 한국생화학분자생물학회) 2017 BMB Reports Vol.50 No.6

The ACKNOWLEDGEMENTS should be corrected as follows, "This research was supported by a grant (Code# PJ0074922012) from the Korean Rural Development Administration, and has been supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education Science and Technology (2010-0022316 and KCG5401011), and the KRIBB/KRCF Research Initiative Program (NAP), Korea. The published article in this journal was a part of the 2013 Doctoral thesis of Jae-Sung Ryu submitted to Wonkwang University, Korea." and not "This research was supported by a grant (Code# PJ0074922012) from the Korean Rural Development Administration, and has been supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education Science and Technology (2010-0022316 and KCG5401011), and the KRIBB/KRCF Research Initiative Program (NAP), Korea."

Novel Trials to Control Harmful Algal Blooms in Seawater

Hyun?Jae Shin,Hoon Cho,Un?Sun Jin,Yun?Kyung Park,Si Wouk Kim 한국생물공학회 2010 한국생물공학회 학술대회 Vol.2010 No.10

급성 심근허혈에 의해 윤발된 승모판 폐쇄부전의 기전에 관한 실험적 연구

강덕현,송현,송재관,김현숙,이재환,임희영,이재원,박성욱,박승정,송명근 대한순환기학회 1999 Korean Circulation Journal Vol.29 No.8

The Effectiveness of Celebrity Endorsers’Match‐up Level and Nationality in Magazine Advertisements for Low‐Involvement Products in Korea

Cho Jae?Hyun 동서언론학회 2008 동서언론 Vol.11 No.-

The purpose of this research is to examine the effectiveness of ad. endorser match?up with the endorsed product and celebrity nationality in terms of attitude toward ad, attitude toward brand and purchase intention.The celebrity endorsers are cultural symbols that represent contemporary cultural trends and can converse with consumers, but only when the celebrities are culturally meaningful. In that sense, this study suggests that celebrity endorsers should be cautiously selected to enhance the match?up level between the characteristics of the product and the image conveyed by the celebrity endorser, by understanding the very cultures where international advertisers want to penetrate.

디지털 치료기술 산업 육성에 따른 투자와 경제적 파급효과

김재현 ( Jae-hyun Kim ),문종윤 ( Jong Youn Moon ),장지은 ( Jieun Jang ),심정연 ( Jung Yeon Sim ),신재용 ( Jaeyong Shin ) 한국보건행정학회 2020 보건행정학회지 Vol.30 No.4

The digital treatment technology industry is one of the core fostering industries of the Moon Jae-in government along with the global trend. The purpose of this study is to compare and analyze the investment and economic ripple effect on the related industries. To this end, we used the industry-related table, which is the actual measurement data for 2015 that the Bank of Korea actually measured and released every 5 years in 2019. The digital treatment technology industry was not clearly classified within Korea’s industrial classification system, so the contents of the industry-related survey were analyzed, and the digital treatment technology industry was reclassified and then analyzed. As a result of the analysis, it was analyzed that the production induction effect of the digital treatment technology-related industry in 2015 was 1.770, the value-added induction effect was 0.875, and the employment induction effect was 19.128, which was higher than that of other industries in Korea. As a result of the analysis of the economic ripple effect (scenario 1), the production inducing effect was about 370 billion won, the added value inducing effect was about 185 billion won, and the employment inducing effect was 4,044 people. The results of this study are expected to play a large role in economic revitalization as the effect of inducing production, increasing employment, and creating added value through fostering the digital treatment technology industry is expected to play a large role in activating the economy. It is expected to play a large role in providing central medical services. Therefore, it is expected that policy support for revitalizing the digital treatment technology industry through active investment support and tax benefits from the government to foster the digital treatment technology industry is necessary.

서울의 Penicillinase Producing Neisseria gonorrhoeae 발생빈도(1998)

김재홍,김준호,반재용,이정우,황성주,정준규,정성태,강진문,조흔정,홍창의,정혜신,이한승,김이선,이봉길,이종호,선영우,한기덕,윤성필,이성훈,안종성,박석범,문승현,조항래,김형섭,류지호,황재영,박준홍,손상욱 한양대학교 의과대학 2001 한양의대 학술지 Vol.21 No.1

In recent years, gonorrhea has been pandemic and remains one of the most common STDs in the world, especially in developing countries. For the detection of a more effective therapeutic regimen and assessing the prevalence of Penicillinase Producing Neisseria gonorrhoeae(PPNG), we have been trying to study the patients who have visited the Venereal Disease Clinic of Choong-Ku Public Health Center in Seoul since 1980 by menas of the chromogenic cephalosporin method. In 1998, 93 strians of N. genorrhoeae were isolated, among which 60(64.5%) were PPNG. The prevalence of PPNG in Seoul, which had been decreased to 39% in 1996 after a peak of 74.3% in 1993, is increased to 64.5% in 1998.

관상동맥질환의 중증도와 혈중지질치 및 아포지단백과의 상관관계

임현주,황종현,류재근,정병천,조용근,채성철,전재은,박의현 慶北大學校 醫科大學 1997 慶北醫大誌 Vol.38 No.1

목적 : 관상동맥질환의 위험인자로서 혈청지질 및 혈장 지단백에 대한 관심이 높아지고 있고 또 아포지단백이 관상동맥 질환을 일으키는데 다른 지질보다 더 중요하다는 연구가 많이 발표되고 있으나 우리나라에서는 아포지단백에 대한 연구가 그리 많지 않은 편이다. 이에 저자등은 혈중지질치와 새로운 위험인자로 알려지고 있는 아포지단백치를 측정하고 이들과 관상동맥질환 중증도와의 상관 관계를 알아보았다. 대상 및 방법 : 관상동맥질환이 의심되어 관상동맥조영술을 실시한 69명의 환자를 대상으로 하였으며 12시간 이상 공복후 혈청을 채취하여 총콜레스테롤, 중성지방, HDL-콜레스테롤, 아포지단백 AI (ape AI), 아포지단백 B (ape B)를 측정하였다. 관상동맥조영상 50%이상의 협착이 있는 혈관의 수 (lesion number), 최대협착을 합한 값 (lesion score), 각 분절의 최대협착을 합한 값 (total score), 가장 심한 협착 값 (peak stenosis) 등으로 관상동맥 중증도를 알아본 다음 이들과 혈청지질치, 아포지단백과의 상관 관계를 비교해 보았다. 상관 관계는 Spearman's correlation coefficient를 구하였다. 결과 : 관상동맥질환의 중증도와 각 지질치 간의 상관 관계를 비교해 보았을때 lesion number와 관계있는 것은 연령 (r=0.2789), 중성지방치 (r=0.2829)이며 lesion score와 관계있는 것은 연령(r=0.2911), 중성지방치0 (r=0.3316), 총콜레스테롤과 HDL-콜레스테롤의 비 (r=0.2361), apo B 치(r=0.2759), apo AI과 apo B의 비 (-0.3154)로 나타났다. Total score는 연령 (r=0.3100), 총콜레스테롤치 (r=0.2452), 중성지방치 (r=0.3022), 총콜레스테롤과 HDL-콜레스테롤의 비 (r=0.2770), apo B치 (r=0.2927), apo AI과 apo B의 비 (r=-0.3408)와 연관이 있었고 peak stenosis는 중성지방 치(r=0.3305), ape B 치 (r=0.2968), apo AI과 apo B의 비 (r=-0.3977)와 관계가 있었다. 연령으로 조정하여 partial correlation을 좌면, 관상동맥조영술상 중증도는 중성지방치 (r=0.3408), apo B 치(r=0.2877), apo AI과 apo B의 비 (r=-0.3460)와 유의한 상관 관계가 있었다. 이중 ape AI과 ape B의 비는 lesion score (r=-0.2640), total score (r=-0.3057), peak stenosis (r=-0.3460)와 유의한 상관관계를 보였다. 결론 : 이상의 결과로 보아 apo B치 그리고 apo AI과 apo B의 비가 관상동맥 중증도의 예견인자로 다른 혈중 지질 치보다 더 유용하다는 것을 알 수 있었다. Objectives : Recently, it was reported that the measurements of apolipoprotein levels may be valuable in the clinical assessment of coronary artery disease severity. However there are a few reports regarding to the relationship between coronary artery disease severity and apolipoprotein levels in Korea. Thus, we measured serum lipid and apolipoprotein levels and studied the relationship between coronary artery disease severity and serum lipids and apolipoproteins levels. Subjects and Methods : The 69 patients who underwent coronary angiography to evaluate chest pain were subjected to this study. We measured the levels of serum cholesterol, triglycerides, HDL cholesterol, apolipoprotein AI(apo AI) and apolipoprotein B(Apo B) and measured the severity of coronary artery disease by lesion number, lesion score, total score and peak stenosis. Then, we studied the relationship between coronary artery disease severity and apolipoproteins and calculated the correlation coefficient. Results : The results were as follows. There are significant correlation(r=0.3) between age, triglycerides, apo B levels, apo AI/B ratio and coronary artery disease severity. In controlling for age, tyiglycerides, apo B levels and apo AI/B ratio shows significant correlation(r=0.3) with coronary artery disease severity. Especially, apo AI/B ratio shows significant correlation(r=0.3) with lesion number, total score and peak stenosis. Conclusion : These results suggest that the apo B levels and the ratio of apo AI/B can be used as significant independent predictor for coronary artery disease severity rather than other serum lipid levels.