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.

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

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.

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

경북지역 주부들의 전통 부엌 세간의 보유 현황 및 이용실태 조사 연구

한재숙,최영희,조연숙,변재옥,한경필,김현옥,정종기,최석현 동아시아식생활학회 2002 동아시아식생활학회지 Vol.12 No.4

Housewives residing in the Kyongsang-Buk-do area were surveyed to determine their ownership of Korean traditional kitchen appliances and their usages. A breakdown of the appliances for the survey was as follows: 16 tableware, 17 household utensils, 15 heating utensils, 14 ceramic and earthen pottery, 6 stone utensils, 9 cooking utensils, 9 utensils made of the dried bamboo and bush clover, and 13 dining tables ("sang"). The types of the appliances with the largest ownerships and most frequently used were as follows: The jeopsi was most frequently owned, followed by the daejeop and the jaengban. The most frequently used item was the jubal,, followed by the daejeop and the jeopsi. Among the wooden utensils, bangmangi was most frequently owned, followed by the chanjang, the che, the doe, mal and hop. The most frequently used household utensil was the chanjang, followed by the takjasang and the doe, mal and hop. The utensil the most people owned for heating was the jujeonja, followed by the seoksoe, the musoesot and the siru. The most frequently used utensil for heating was the jujeonja, the musoesot and the seoksoe, in the order. As for the ceramic and earthen pottery, hangari and dok were owned and used most frequently. The maetdol and the jeolgu, though very low in their ownership rate, were most frequently owned items among the stoned utensils. The kal and the doma were the most frequently owned and used cooking utensils. The sokuri, and the chaeban and the baguni were the most frequently owned among the utensils made of the dried bamboo, bush clover and straw, while the sokuri was used the most frequently, followed by the chaeban and the jori. Among the dining tables, the kyojasang was the item most frequently owned, followed by the seonban and the chaeksangban, while the wonban was the most frequently used, followed by the kyojasang and the chaeksangban.

2단계 醱酵에 의한 人蔘食醋와 市販食醋의 品質比較

鄭宰顯,趙載敏,崔元碩,曺柱鉉 충주대 2003 産業科學論文集 Vol.11 No.-

본 연구는 인삼의 약리성분과 식초의 기능성을 갖는 인삼식초를 제조하기 위하여 시판 식초와 2단계 발효를 거친 인삼식초와의 품질 을 비교 평가하여 다음과 같은 결과를 얻었다. 가. 인삼식초의 산도는 시판식초보다 약간 낮았으며, pH는 3.7정도로 시판식초보다 약간 높았다. 나. 인삼식초 중에는 fructose, maltose, sucrose, glucose등의 유리당이 존재하였으며 시판중인 식초에는 fructose의 양이 많이 함유되어 있었으며 기타 maltose, sucrose 등도 일부 존재하였다. 다. 인삼식초에는 acetic acid, tartaric acid, propionic acid, lactic acid, malic acid, succinic acid 등의 유기산이 함유되어 있었고 일반 시판식초에는 oxalic acid, citric acid, malic acid, acetic acid등을 함유하고 있었다. We producted the ginseng vinegar through two stages fermentation(alcohol fermentation and acetic acid fermentation). At the first stage, ginseng wine contained 17% alcohol was producted at the 11th day. And through the second stage, acetic acid fermentation ginseng vinegar of which total acidity is 5.8% were produced. In comparison with commercial vinegars for physicochemical quality, acidity of ginseng vinegar was lower than those of commercial vinegars and ph was higher than those of commercial vinegars. The major free sugar compositions in ginseng vinegar were fructose, maltose, sucrose and glucose and in commercial vinegar were fructose, sucrose and maltose. The major organic acid compositions were acetic acid, tartaric acid, propionic acid, lactic acid, malic acid and succinic acid and in commercial vinegar were oxalic acid, citric acid, malic acid and acetic acid.

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.

감속기 기어의 결함진단에 관한 연구

이재현,국재창,이재응 중앙대학교 기술과학연구소 1999 기술과학연구소 논문집 Vol.29 No.-

본 논문에서는 감속기 기어의 결함진단의 문제가 고려되었고, 시간-주파수 영역의 분석 방법인 위이블렛 변환을 결함진단 연구에 이용하였다. 웨이블렛 변환은 시간-주파수 영역에서 좋은 성능을 나타내며 다양한 기본 웨이블렛 함수를 가지고 있고 융통성과 적응력이 있는 변환방법과 해상도를 가지고 있어서, 급격히 변화하는 신호나 비정상 충격신호를 위치신호의 손실없이 잘 분석할 수 있는데, 이는 기어면에서 금속충돌이 일어나고 여거 기어이를 가지고 있는 복잡한 기어 시스템에서 더욱 유용하게 쓰일 수 있다. 또한 웨이블렛이 가진 주요 특성 중 하나인 잡음제거(de-noise) 기능을 사용하여 잡음이 합쳐져 있는 실제 신호를 더욱 효과적으로 분석 할 수 있었다. 실험대상은 두 쌍의 기어 물림이 있는 기어구동계를 사용하였고, 먼저 실험대상인 기어열에서 이론적으로 발생할 수 있는 싸인파들의 합성으로 이루어진 신호를 가지고 시뮬레이션을 실시하였고, 실험장치를 통해 정상상태기어에서의 신호와 기어에 인위적으로 발생시틴 결함에 의해 발생되는 신호를 측정하였으며 이러한 신호를 웨이블렛 변환하는 방법을 통해 결함을 분석하였다. In this paper, the problems of the fault detection of gear trains are considered, and the wavelet transforms are applied to evaluate the performance of detecting the incipient gear damage with real experimental data. The wavelet transform enables one to look at the evolution in time of a signal's frequency content. This property make it very suitable for the detection of transient vibrations generated by developing localized faults in gear trains. Recent applications of the wavelet technique have focused on the use of DWT(Descret Wavelet Transform) coefficients only. In this study, the wavelet denosing is also applied to remove the effect of the noise in the measured vibration signals. The denoised wavelet map is found to display distinctive features in the presence of several kinds of fault in a tooth.

발열을 동반한 호중구감소증에서 Cefepime 단독투여와 Ceftazidime 및 Tobramycin 병합투여의 효능비교

정현욱,채제욱,강미라,양정채,문치숙,기현균,장현하,오원섭,김기현,백경란,이남용,송재훈 대한감염학회 2004 감염과 화학요법 Vol.36 No.6

목적 : 국내에서 발열을 동반한 호중구감소증이 있는 악성 종양환자에게 경험적 항생제로 베타락탐계 항생제와 아미노배당체의 병합요법의 사용이 일반적이다. Cefepime은 광범위 항균 작용을 가지고 있어, 그람 음성균 뿐만 아니라 그람 양성균에 대해서도 우수한 효과를 나타낸다. 재료 및 방법: 발열을 동반한 호중구감소증이 있는 악성 종양환자를 대상으로 무작위, 공개, 비교 연구를 시행하였다. 대상 환자를 무작위로 cefepime 단독요법군과 ceftazidime 및 tobramycin 병합요법군으로 나누어 투여하고 각각의 임상적 효능과 안전성을 비교하였다. 구강및 인후 점막염이 있는 환자에서 분리된 녹색 연쇄알 구균에 대한 항생제 내성 정도를 조사하였다. 결과 : 대상환자 89명 중 CA 투여군이 48예(53.9%), CT 투여군이 41예(46.1%)이었다. 발열의 유형별로 MDI는 18예(20.2%), CDI는 9예(10.1%), UF는 62예(69.7%)로 두 군 간에 차이가 없었다. CA 투여군과 CT 투여군의 임상적 호전률은 시험약 투여 후 2-4일째 각각 91.7%, 85.4% (P=0.31), 치료 종료 시 각각 91.7%, 100% (P=0.15)로 두 군간에 유의한 차이가 없었다. 치료 종료 시 CA 투여군과 CT 투여군의 세균학적 소실률은 모두 100%로 두 군간의 유의한 차이가 없었다(P=0.78). 점막염이 있는 환자로부터 녹색 연쇄알 구균이 분리된 경우는 25예(28.1%)이었으며, 분리된 녹색 연쇄알 구균은 penicillin, ceftriaxone, cefepime, vancomycin에 모두 감수성을 보였다. 약제 관련 이상 반응의 발생 빈도도 두 군간에 유의한 차이가 없었다. 결론 : 발열을 동반한 호중구감소증이 있는 악성 종양환자의 경험적 항생제로서 cefepime 단독요법은 ceftazidime 및 아미노배당체의 병합요법만큼 효과적이고 안전하였다. Background : Broad-spectrum antibiotic therapy has been recommended as an empirical regimen in cancer patients with febrile neutropenia. Cefepime is a fourth generation cephalosporin with good activity against both gram-positive cocci and gram-negative bacilli. Materials and Methods : To compare the efficacy and safety of cefepime alone with ceftazidime plus tobramycin as empirical regimen for adult cancer patients with febrile neutropenia, a randomized, open label, comparative trial was performed. If the patient showed clinical improvent 72 hours, antibiotic could be changed to oral ciprofloxacin. Clinical and microbiological responses were determined at 72 hours and at the end of therapy. To investigate the antimicrobial resistance of viridans streptococci, swab cultures were obtained from throat in all enrolled patients and antimicrobial susceptibility tests were performed by using microdilution method according to the NCCLS. Results : A total of 89 patients were enrolled. Forty-eight patients received cefepime alone (CA), and 41 patients received ceftazidime plus tobramycin (CT). Demographic and baseline clinical characteristics were similar in both groups (P>0.05). The initial clinical success rate at day 2-4 in group CA (91.7%) was similar with that in CT group (85.4%) (P=0.31). At the end of therapy, the final clinical success rate in CA group (91.7%) was similar to that in CT group (100%) (P=0.15). In 18 patients, with microbiologically defined infections, the eradication rate was 100% in both groups. Adverse events including liver dysfunction (21.3%) and renal dysfunction (2.2%), were similar in both groups (P=0.87). Viridans streptococci were isolated from the throat cultures in 25 cases, and all of these strains were susceptible to penicillin (MIC_(90) 0.12 ㎍/mL), cefepime (1 ㎍/mL), and vancomycin (0.12 ㎍/mL). Conclusion : Efficacy and safety of cefepime monotherapy was comparable to the combination of ceftazidime and tobramycin. It could be used as an alternative empirical regimen for treating cancer patients with febrile neutropenia.