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.

Tuberculosis risk is associated with genetic polymorphisms in the LRP2, CUBN, and VDR genes

Sung‑Soo Kim,Sang In Lee,Hyun‑Seok Jin,Sangjung Park 한국유전학회 2020 Genes & Genomics Vol.42 No.10

Background Vitamin D (Vit. D) is used extensively during tuberculosis treatment. Low levels of serum Vit. D increase the risk of active tuberculosis development. Altered expression of the proteins involved in Vit. D metabolism impairs cathelicidin production, thereby increasing the host susceptibility to tuberculosis. Objective We are trying to investigate whether single nucleotide polymorphisms (SNPs) in LRP2, CUBN, and VDR genes could afect tuberculosis development. Methods We included participants of the Korean Association Resource (KARE), part of the Korean Genome and Epidemiology Study (KoGES), and used their recorded data. A total of 8840 people (4182 men and 4658 women) were eligible subjects. The 5-kb regions from the ends of transcripts of GC, LRP2, CUBN, and VDR genes were amplifed to select 13, 47, 70, and 15 SNPs, respectively. For association analysis and statistical analysis, PLINK version 1.07 and PASW Statistics version 18.0 were used. Results Signifcant correlation was observed in 11, 2, and 1 SNPs in LRP2, CUBN, and VDR genes. The efect of rs6747692 of LRP2 on transcription factor binding was confrmed using RegulomeDB. We confrmed that rs2239182 of VDR is located in the genomic eQTL region and can afect transcription factor binding and gene expression. Conclusions Genetic polymorphisms in genes encoding proteins involved in Vit. D metabolism infuence immune system components. Therefore, such polymorphisms may infuence the susceptibility to Mycobacterium tuberculosis invasion and alter the defense mechanisms against Mycobacterium tuberculosis infection. The correlation between genetic variation and tuberculosis development can provide new guidelines for the management of tuberculosis.

Differential Manifestation of Ocular Phenotypes in TALEN-mediated p19arf Knockout FVB/N and C57BL/6J mouse lines

Jin‑Sung Park,Joo‑Il Kim,Hyun‑Jin Lim,Soo‑Kyung Ryu,Euna Kwon,Kang‑Min Han,Ki‑Taek Nam,Han‑Woong Lee,Byeong‑Cheol Kang 한국유전학회 2020 Genes & Genomics Vol.42 No.9

Background p19arf, primarily known as a tumor suppressor, has also been reported to play an essential role in normal development of mouse eyes. Consistently, lack of p19arf has been associated with ocular defects, but the mixed background of the knockout (KO) mouse strain used raised a concern on the accuracy of the phenotypes observed in association with the targeted gene due to genetic heterogeneity. Object We carried out a study to investigate into the efect of genetic background on the manifestation of p19arf KO associated phenotypes. Methods We characterized the phenotypes of novel p19arf KO mouse lines generated in FVB/N and C57BL/6J using a transcription activator-like efector nuclease (TALEN) system in comparison to the reported phenotypes of three other p19arf-defcient mouse lines generated using homologous recombination. Results Ninety-fve percent of FVB/N-p19arf KO mice showed ocular opacity from week 4 after birth which worsened rapidly until week 6, while such abnormality was absent in C57BL/6J-p19arf KO mice up to the age of 26 weeks. Histopathological analysis revealed retrolental masses and dysplasia in the retinal layer in FVB/N-p19arf KO mice from week 4. Besides these, both strains developed normally from birth to week 26 without increased tumorigenesis except for a subcutaneous tumor found in a C57BL/6J-p19arf KO mouse. Conclusion Our fndings demonstrated surprisingly variable manifestation of p19arf-linked phenotypes between FVB/N and C57BL/6J mice, and furthermore between our mouse lines and the established lines, indicating a critical impact of genetic background on functional study of genes using gene targeting strategies in mice.

입력전류 파형 개선형 단상 정류기의 토폴로지

이상현(Sang-Hyun Lee),박진민(Jin-Min Park),문상필(Sang-Pil Mun),서기영(Ki-Young Suh) 한국조명·전기설비학회 2003 한국조명·전기설비학회 학술대회논문집 Vol.2003 No.-

For small capacity rectifier circuits such as these for consumer electronics and appliances, capacitor input type rectifier circuits are generally used. Consequently, various harmonics generated within the power system become a serious problem. Various studies of this effect have been presented previously. However, most of these employ switching devices, such as FETs and the like. The absence of switching devices makes systems more tolerant to over-load, and brings low radio noise benefits. We propose a power factor correction scheme using a LC resonant in commercial frequency without switching devices. In this method, it makes a sinusoidal wave by widening conduction period using the current resonance in commercial frequency, Hence the harmonic characteristics can be significantly improved, where the lower order harmonics, such as the fifth and seventh order are much reduced. The result are confirmed by the theoretical and experiment implementations.

예비 영유아교사를 위한 자아탄력성 증진 프로그램이 자아탄력성과 공감능력에 미치는 영향

박진성 ( Park Jin-sung ),신현정 ( Shin Hyun-jung ) 미래유아교육학회 2017 미래유아교육학회지 Vol.24 No.2

본 연구의 목적은 예비 영유아교사를 위한 자아탄력성 증진 프로그램이 자아탄력성과 공감능력에 미치는 효과를 살펴보는 것이다. 본 연구에서 개발된 예비 영유아교사를 위한 자아탄력성 프로그램은 자신감 및 유능감, 긍정적 사고, 문제해결능력, 감정조절 및 관리, 친밀한 태도와 행동, 대인관계능력을 통하여 자아탄력성 향상을 세부목표로 하였다. 본 연구의 대상은 4년제 대학의 예비 영유아교사 99명이며, 실험집단에 12회에 걸쳐 자아탄력성 증진 프로그램을 실시하였다. 프로그램의 평가를 위하여 Klohnen(1996)이 개발한 자기보고식 자아탄력성 도구를 박현진(1997)에 번역한 자아탄력성도구와 Mehrabian & Epstein(1972), Davis(1980), Bryant(1982) 도구를 전병성(2003)이 수정한 공감능력 검사 도구를 통하여 검사를 실시하였으며, 수집된 자료는 t-검증을 실시하였다. 본 연구 결과, 예비 영유아교사를 위한 자아탄력성 증진 프로그램은 예비 영유아교사의 자아탄력성에서 낙관적 태도와 분노조절, 자아탄력성 전체에 효과가 있었으며, 정서공감과 인지공감 등 공감능력 모두에 효과를 나타냈다. The purpose of this study was to investigate the effects of the ego-resiliency enhancing program on ego-resiliency and empathy of pre-service early childhood teachers. The contents of ego-resilience enhancing program for pre-service early childhood teachers included self-confidence, positive thinking, problem solving, emotion regulation, intimate attitude and behavior, and interpersonal relationship. The subjects of this study were 99 pre-service early childhood teachers. The experimental group had 12 sessions with the ego-resiliency enhancing program. The rating scale was used with a rating scale of ego-resiliency by Hyun-Jin Park(1997) and a rating scale of empathy by Byung-Suk Jun(2003). The data were analyzed by t-test. The result of this study was that the ego-resiliency enhancing program was effective for improving ego-resiliency and empathy for especially positive behavior, anger adjustment, cognitive empathy and emotional empathy of pre-service early childhood teachers.

기관지폐 이형성증의 임상 양상: 다기관 연구

성기혜 ( Ki Hye Sung ),김민희 ( Min Hee Kim ),김은령 ( Eun Ryoung Kim ),심재원 ( Jae Won Shim ),이정주 ( Jung Ju Lee ),임재우 ( Jae Woo Im ),진현승 ( Hyun Seung Jin ) 대한주산의학회 2009 Perinatology Vol.20 No.3

목적: 최근 극소 저출생 체중아의 생존율의 개선으로 기관지폐 이형성증(bronchopulmonary dysplasia, BPD)이 늘고 있다. 다기관 연구에 의해 전국적인 BPD의 역학, 임상 양상과 각 병원 간의 차이를 조사하여 향후 우리나라의 BPD 감소와 중증도를 줄이는 것을 목적으로 본 연구를 시행하였다. 방법: 2005년 6월부터 2007년 5월까지 건국대학교병원, 영등포 성애병원, 강북삼성병원, 중앙대학교병원, 건양대학교병원, 강릉아산병원의 신생아 집중 치료실에 입원하였던 신생아 4,476명을 대상으로 하였다. BPD의 진단 기준은 비전형적인 BPD를 포함하여 병인적인 분류를 하고 있는 Ogawa 등의 분류법을 이용하여 신생아 호흡 곤란 증후군(respiratory distress syndrome, RDS)과 전형적 또는 미만성 혼탁의 방사선 소견, 산전 감염의 유무에 따라 6가지 type으로 분류하였다. 또한 전체 신생아의 출생체중 분포와 생존율, 각 출생체중 군별 BPD의 발생률, 병태 비율, 사망률 등을 조사하고, 이 후 재택 산소요법 시행 여부와 미숙아 망막증, 괴사성 장염 등의 합병증 여부를 조사하였다. 결과: 생후 28일째 산소 치료가 필요한 신생아는 89명이었고, 이 중 Ogawa 분류법에 의한 BPD 환아는 70명(1.6%)이었으며, 특히 1,500 g 미만의 환아 237명 중 60명(25.3%)이었다. 생후 28일 이상 생존율은 98.7%이고, 사망 예는 없었으며 평균 재원 기간은 97.8±51.2일(43~405일)이었다. BPD는 900~999 g, 1,000~1,249 g의 체중 군에서 발생률이 각각 15명(21.4%)으로 가장 높았으며, 교정 36주 이후에도 산소투여가 필요한 중증 BPD의 경우 900~999 g의 체중 군에서 7명(23.3%)로 가장 높았다. Ogawa 분류법으로 BPD의 각 병태 비율로는 RDS 이후에 나타나는 I, II형이 각각 전체의 17예(24.3%), 44예(62.9%)로 대다수를 차지하였다. 이외에도 III`형은 2예(2.9%), IV형은 2예(2.9%), V형은 5예(7.1%)이었고, III형, VI형은 없었다. 재택 산소요법은 8예에서 시행되어 전체의 11.4%였으며, 이 중 BPD I형이 7예로 87.5%를 차지하였다. 미숙아 망막증은 35명(50.0%)에서 발생하였으며, 700 g 이하 신생아에서 9예(26.5%)로 가장 많았다. 또한 괴사성 장염은 3명(4.3%)이었다. 결론: 본 연구는 국내에서 처음으로 진행된 BPD의 전국적인 다기관 역학 조사로, 대상 신생아의 Ogawa 분류에 의한 BPD 유병률은 1.6% 이었고 1,500 g 미만 신생아의 25.3%이었으며, 전체 신생아의 BPD 70명 중 Ogawa 분류의 I, II형이 각각 24.3%, 62.9%로 대다수를 차지하였다. Purpose: As the neonatal intensive care advanced, the incidence of neonatal bronchopulmonary dysplasia (BPD) has increased. We conducted a multi-center investigation of the prevalence of BPD in six hospitals to investigate the epidemiology of BPD in Korea. Methods: Retrospective reviews ware performed for survival rate, prevalence of BPD of total 4,476 newborn infants who were admitted to neonatal intensive care unit in Konkuk university hospital, Sung-Ae General hospital, Kangbuk Samsung hospital, Chung-Ang university hospital, Konyang university hospital, and Gangneung Asan hospital between June, 2005 and May, 2007. By Ogawa, BPD was defined as oxygen dependency at 28 days after birth, with respiratory distress symptoms and the change of chest x-ray finding, and classified as 6 subtypes. Classic BPD was defined as oxygen dependency at 36 weeks of postmenstrual age. Results: Survival rate at 28 day after birth was 98.7%. BPD infants by Ogawa classification were 70 (1.6% of overall newborn infants), classic BPD infants were 30 (0.7%). Especially, among 237 preterm infants with birth weight less than 1,500 gram who survived to 28 days of life, 60 (25.3%) had BPD by Ogawa classification and 23 (9.7%) had classic BPD. In Ogawa classification, infants with RDS as type I and II, were 17 infants (24.3%) and 44 infants (62.9%). Home oxygen therapy was performed 8 infants (11.4%). Prevalence of retinopathy of prematurity was 35 infants (50.0%), necrotizing enterocolitis was 3 infants (4.3%), and intraventricular hemorrhage was 6 infants (8.6%). Conclusion: Prevalence of BPD infants was 1.6% of overall newborn, 25.3% of preterm infants with birth weight less than 1,500 gram. Among 70 BPD infants, BPD by Ogawa classification with history of RDS as type I and II were 24.3%, 62.9% as the majority of BPD. This study would be the first report of epidemiology of Korean BPD infants by multi-center study.

고조리서와 종가의 무김치 비교 연구

이현진,이상원,전형주,정혜정,Lee, Hyun-Jin,Lee, Sang-won,Jeon, Hyeong-ju,Chung, Hea-jung 한국식품영양학회 2015 韓國食品營養學會誌 Vol.28 No.5

The purpose of this research aims to reveal how radish kimchi (Jong-ga) differs in Jong-ga recipes and old cookbooks. To accomplish this, old cookbooks ("Soowoonjabbang", "Jusiksiui", "Eumsikbangmunnira", "Siuejunsuh", "Banchandeungsok", and "Buinpilji") were reviewed and 8 Jong-ga recipes (Seogye Park Se-dang from the Bannam Park clan Jong-ga, Myungsukgong from the Changnyeong Jo clan Jong-ga, Nampa Park Jae-gyu from the Milyang Park clan Jong-ga, Geunggudang Kim Joong-jeung from the Gwangsan Kim clan Jong-ga, Dongchundang Song Jun-gil from the Eunjin Song clan Jong-ga, Myeongjae Yun Jung from the Papyung Yun clan Jong-ga, Daeseunggong Ryu Cha-dal from the Munhwa Ryu clan Jong-ga, Inmukjae Son Sung-jeung from the Milseong Son clan Jong-ga) from five areas were reviewed. We classified the radish kimchi into five categories, radish kimchi, Dongchimi, kkakdugi, Seokbakji and Nabak kimchi and other kimchi. According to old cookbooks, most kimchi was made with radish, cabbage, cucumber, pear, yuju, fish meat, and salt. Modern Jong-ga is made of seasoned radish, sticky rice paste, seafood, sugar, powdered pepper, fish sauce and salt. This study helps to understand notable clans' cultures via their recipes for kimchi.

Effect of Highly Pressurized Hydrogen Gas Charging on the Hydrogen Embrittlement of API X70 Steel

Dong-Su Bae,Chi-Eun Sung1,Hyun-Ju Bang,Sang-Pill Lee,Jin-Kyung Lee,In-Soo Son,조영래,Un-Bong Baek,Seung-HoonNahm 대한금속·재료학회 2014 METALS AND MATERIALS International Vol.20 No.4

During the use of API X70 steel as a pipeline structural material for the transportation of natural gas,hydrogen embrittlement can occur due to the hydrogen contained in natural gas. The aim of this study is toinvestigate the effects of the hydrogen content under high-pressure hydrogen gas conditions on the hydrogenembrittlement of air-cooled API X70 steel. The air-cooled API X70 steel was manufactured by hot rollingand was then air-cooled to room temperature. Tensile test specimens were held for 0 h, 1000 h, and 2000 hwithin a pressure vessel filled with 100% hydrogen gas at a gas pressure of 10 MPa, with the tensile teststhen performed at room temperature. The microstructure of the API X70 steel consists of coarse polygonalferrite, coarse pearlite, and fine acicular ferrite. The yield and tensile strength increased and elongationdecreased considerably after a holding time of 2000 h compared to those of 0 h and 1000 h within the pressurevessel. The morphology of the fracture surface changed from ductile to brittle upon hydrogen gas charging. Secondary cracks were observed in both of the hydrogen-gas-charged specimens. No external cracks wereformed on the surface of the tensile-tested specimen with a 0 h holding time; however, many external crackswere observed on the specimen surface subjected to hydrogen gas charging.

Interaction of <i>Veratrum nigrum</i> with <i>Panax ginseng</i> against Obesity: A Sang-ban Relationship

Park, Jinbong,Jeon, Yong-Deok,Kim, Hye-Lin,Lim, Hara,Jung, Yunu,Youn, Dong-Hyun,Jeong, Mi-Young,Kim, Hyun-Ju,Kim, Sung-Hoon,Kim, Su-Jin,Hong, Seung-Heon,Um, Jae-Young Hindawi Publishing Corporation 2013 Evidence-based Complementary and Alternative Medic Vol.2013 No.-

<P>Obesity has become a major health threat in developed countries. However, current medications for obesity are limited because of their adverse effects. Interest in natural products for the treatment of obesity is thus rapidly growing. Korean Medicine (KM) is characterized by the wide use of herbal formulas. However, the combination rule of herbal formulas in KM lacks experimental evidence. According to <I>Shennong's Classic of Materia Medica</I>, the earliest book of herbal medicine, <I>Veratrum nigrum</I> (VN) has antagonistic features against <I>Panax ginseng</I> (PG), and the PG-VN pair is strictly forbidden. In this study, we have shown the effects of PG, VN, and their combination on obesity in high-fat (HF) diet-induced obese mice and in 3T3-L1 cells. PG, VN, and PG-VN combination significantly reduced weight gain and the fat pad weight in HF diet-induced obese mice. They also significantly decreased lipid accumulation and the expressions of two major adipogenesis factors, PPAR<I><I>γ</I></I> and C/EBP<I><I>α</I></I>, in 3T3-L1 cells. In addition, the PG-VN combination had synergistic effects compared with the mixture of extracts of PG and VN on inhibition of PPAR<I><I>γ</I></I> and C/EBP<I><I>α</I></I> expressions at lower doses. These results indicate a new potential anti-obese pharmacotherapy and also provide scientific evidence supporting the usage of herbal combinations instead of mixtures in KM.</P>

Nanogenerators: Fully Rollable Transparent Nanogenerators Based on Graphene Electrodes (Adv. Mater. 19/2010)

Choi, Dukhyun,Choi, Min-Yeol,Choi, Won Mook,Shin, Hyeon-Jin,Park, Hyun-Kyu,Seo, Ju-Seok,Park, Jongbong,Yoon, Seon-Mi,Chae, Seung Jin,Lee, Young Hee,Kim, Sang-Woo,Choi, Jae-Young,Lee, Sang Yoon,Kim, Jo WILEY-VCH Verlag 2010 ADVANCED MATERIALS Vol.22 No.19

<B>Graphic Abstract</B> <P>The cover shows an image of fully rollable transparent nanogenerators synthesized using chemical vapor deposition grown large-scale graphene sheets as transparent electrodes and piezoelectric ZnO nanorod arrays. Sang-Woo Kim, Jae-Young Choi, and co-workers report on p. 2187 the electrical and structural stability of the nanogenerators, with excellent charge scavenging performance under external mechanical loads such as bending and rolling. This study shows that graphene-based nanogenerators are very promising for self-powered rollable transparent device applications. <img src='wiley_img_2010/09359648-2010-22-19-ADMA201090066-content.gif' alt='wiley_img_2010/09359648-2010-22-19-ADMA201090066-content'> </P>