Effect of Strain Aging on Tensile Behavior and Properties of API X60, X70, and X80 Pipeline Steels

Sang‑In Lee,Seung‑Yong Lee,Seok Gyu Lee,Hwan Gyo Jung,Byoungchul Hwang 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.6

The effect of strain aging on tensile behavior and properties of API X60, X70, and X80 pipeline steels was investigated inthis study. The API X60, X70, and X80 pipeline steels were fabricated by varying alloying elements and thermomechanicalprocessing conditions. Although all the steels exhibited complex microstructure consisting of polygonal ferrite (PF), acicularferrite, granular bainite (GB), bainitic ferrite (BF), and secondary phases, they had different fractions of microstructuresdepending on the alloying elements and thermomechanical processing conditions. The tensile test results revealed that yieldingbehavior steadily changed from continuous-type to discontinuous-type as aging temperature increases after 1% pre-strain. After pre-strain and thermal aging treatment in all the steels, the yield and tensile strengths, and yield ratio were increased,while the uniform elongation and work hardening exponent were decreased. In the case of the X80 steel, particularly, thedecrease in uniform elongation was relatively small due to many mobile dislocations in PF, and the increase in yield ratiowas the lowest because a large amount of harder microstructures such as GB, BF, and coarse secondary phases effectivelyenhanced work hardening.

판상형 충전제의 함량과 배향에 따른 PP복합체의 영률 변화 연구

서상범(Sang Bum Seo),이용현(Yong Hyun Lee),정선경(Sun Kyoung Jeong),이승구(Seung Goo Lee),이기윤(Kee Yoon Lee) 한국고분자학회 2012 폴리머 Vol.36 No.2

이 논문은 판상형 충전제의 함량과 배향에 따라 폴리프로필렌 복합체의 영률 변화에 미치는 영향을 연구 하였다. 이론적인 예측은 Lee와 그의 연구자들에 의해 제안된 두 개의 종횡비, ρα=a1/a3과 ρβ=a1/a2 를 이용하여 3차원 타원체의 형상을 계산하였고 실험값과 비교 분석하였다. 판상형 충전제로 운모와 탈크를 사용하였다. 충전제의 형태는 SEM을 이용해 관찰하였고, 종횡비는 고분자의 흐름을 기준으로 좌표축을 설정하여 통계적 방법으로 계 산하였다. 충전제가 운모인 경우에 ρα=13.5와 ρβ=1.8이었고, 탈크의 경우는 ρα=3.8과 ρβ=1.4이었다. 또한 충전제 의 2개의 종횡비와 함량이 기계적 물성에 미치는 영향을 실험적으로 연구하였다. 운모의 경우 30 wt% 함량일 때 E11이 약 2.7배 향상되었다. 탈크의 경우는 E11이 약 2.3배 향상하였다. This paper studied the effects of the content and the orientation of the disk shape fillers on the modulus of PP composites. The experimental results were compared with the theoretical calculations which included the three dimensional ellipsoids and analyzed by two aspect ratios, ρα=a1/a3 and ρβ=a1/a2 proposed by Lee and his researchers. Mica and talc were used as disk shape fillers in the composites. The shapes of mica and talc were observed by SEM and aspect ratios were statistically calculated. For the case of mica, the average aspect ratios were ρα=13.5 and ρβ=1.8, and for the case of talc, they were ρα=3.8 and ρβ=1.4. Also, the effects of two aspect ratios and the content of filler on the mechanical properties were studied: For 30 wt% of mica, E11 increased up to about 2.7 times, and for the other case of talc, E11 increased up to about 2.3 times, respectively.

Pneumatosis intestinalis and portal venous gas secondary to gefitinib therapy for Lung adenocarcinoma

( Joo Young Lee1 ),( Hye-suk Han ),( Sung-nam Lim ),( Young Kwang Shim ),( Yong Hyeok Choi ),( Ok-jun Lee ),( Ki Hyeong Lee1 ),( Seung Taik Kim ) 대한내과학회 2011 대한내과학회 추계학술대회 Vol.2011 No.-

Novel Methylation Biomarker for Non-invasive Diagnostics in Lung Cancer

오태정,( Chang Hun Lee2 ),( Min Ki Lee ),( Yeul Hong Kim ),( Sang Yull Lee ),( Hyo Sung Jeon ),( Shin Yup Lee ),( Seung Soo Yoo ),( Jae Yong Park ),( Sung Whan An ) 대한결핵 및 호흡기학회 2012 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.114 No.-

To identify aberrantly hypermethylated DNA in lung cancer cells we established a genome-wide analysis for hypermethylation sites, namely Methyl DNA Isolation and Amplification (MeDIA) coupled-CpG microarray analysis. In the comprehensive methyaltion profiling analysis between human lung cancer, A549 cells and normal NHBE cells, we observed that several clusters of genes show a significant level of aberrancy in CpG island methylation pattern in cancer cells compared to normal cells. We further identified PCDHGA12 gene as a new marker of non-invasive diagnostics for lung cancer based on followings. 1) Transcription of PCDHGA12 gene is reactivated after treatment of A549 cells with demethylating agent. 2) Bisulfide clonal-sequencing reveals that CpG island of PCDHGA12 shows a distinctive differential methylation between two cell lines. 3) Pyrosequencing-based quantitative methylation assay for such region in tumor and non-tumorous tissues from lung cancer patients shows aberrant hypermethylation in 37 (92%) of the 40 tumor tissues. In clinical validation by pyrosequencingin induced-sputum of lung cancer patients (n=87) and healthy controls (n=51), we observed aberrant hypermethylation incident at significantly elevated level in samples derived from lung cancer patients. According to the optimal threshold calculated by ROC curve analysis, sensitivity and specificity of PCDHGA12 was 86.2% and 82.4%, respectively. PCDHGA12 methylation status could be a potential methylation biomarker alone or combined with others for the screen and the detection of relapse of lung cancer.

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.

단상 유도형 동기 전동기(LSPM)의 특성해석에 관한 연구

정대성,김승주,이진헌,최재학,이주,Jung, Dae-Sung,Kim, Seung-Ju,Lee, Jin-Hun,Choi, Jae-Hak,Lee, Ju 한국조명전기설비학회 2007 조명·전기설비학회논문지 Vol.21 No.3

가전분야에서의 전동기 효율향상을 통한 에너지 소비절감 효과는 상당히 크지만 이를 위한 전동기의 설계/해석 기술 확보가 아직은 미흡한 상태이다. 이에 따라 유도형 동기전동기가 제안되었지만, 유도형 동기 전동기는 유도전동기와 통기전동기의 특성을 동시에 가지고 있어, 해석 및 설계가 쉽지 않다. 따라서 본 논문에서는 기존의 냉장고 압축기용 전동기인 단상유도전동기를 대처할 수 있는 단상 유도형 동기전동기를 이용해 파라미터에 따라 특성이 어떻게 바뀌는가에 대해 서술하였다. 그에 따라 단상유도전동기의 정상상태 특성을 해석하고 제안모델의 성능을 기존모델과 비교하고 실험하여 해석결과의 신뢰성을 검증한다. 또한 본 논문에서는 제안모델의 기존 고정자 형상이나 권선 스팩을 유지하고 회전자의 형상이나 구조만을 변경시켜 성능향상을 도모하였다. 해석방법으로는 전자장 수치 해석적인 방법으로 널리 이용되고 있는 유한요소법(Finite Element Method : FEM)을 이용하였다. Electric motor efficient improvement from home appliance field is important to the effect reducing the energy consumption. But the electric motor design/analysis technology is still insufficient. Specially the electric motor design/analysis technology of satisfying characteristic of both the induction motor and the synchronous motor such as Line start permanent motor. Therefore the electric motor design/analysis technology is urgently demanded reliability. This paper proposes the sing1e-phase line-start permanent magnet motor to develop the motor it with be able to alternate the sing-phase induction motor it is a refrigerator compressor motor. The sing-phase induction motor is analyzed in the steady state. And we have a certification test to compare our single-phase line-start permanent magnet motor with the sing-phase induction motor. In order to improve the performance, the stator of the single-phase line-start permanent magnet motor is same as the stator of the sing-phase induction motor and changes the rotor form and has the permanent magnet. It used the Finite Element Method(FEM) which is widely used with electronic-magnetic field numerical analysis method.

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.

외과영역 복강경수술의 임상치험

강동수(Dong Soo Kang),최상용(Sang Yong Choi),이광찬(Kwang Chan Lee),김진승(Chin Seung Kim) 대한소화기학회 1993 대한소화기학회지 Vol.25 No.5

N/A The 19 months clinical experiences about 634 cases of laparoscpic surgery were reviewed at Sung-Ae General Hospital from July 1991 to Jan. 1993 The results were as follows; Among 168 cases of laparoscopic cholecystectomy and 5 cases of laparoscopic CBD exploration, we obtained better results with advantages of laparoscopic surgery including few complications, less morbidity and early return to work. In series of 361 cases of laparoscopic appendectomy, we obtained superior results especially in the cases of 1) uncertainty of clinically suspected appendicitis, 2) right lower quadrant pelvic pain without other pathology and 3) patients who wanted early return to work. In series of spontaneous pneumothorax with bullae and recurrent pneumothorax, the thoracoscopic bullectomy was much superior than open bullectomy. The laparoscopic Taylor procedures and laparoscopic bandlysis will be better choice in the management of intractable pain in duodenal ulcer and postoperative adhesion. The diagnostic laparoscopy will be much useful in the blunt and penetrating abdominal trauma.

백서에서 수술 후 복부 유착방지용 재료들의 효능평가

심희수(Hee Soo Shim),이영우(Young Woo Lee1),이영무(Young Moo Lee),오영하(Young Ha Oh),권성원(Sung Won Kwon),김진홍(Jin Hong Kim),손승국(Seung Kook Sohn) 대한외과학회 2002 Annals of Surgical Treatment and Research(ASRT) Vol.63 No.3

BEZ235 (PIK3/mTOR inhibitor) Overcomes Pazopanib Resistance in Patient-Derived Refractory Soft Tissue Sarcoma Cells

Kim, Hee Kyung,Kim, Sun Young,Lee, Su Jin,Kang, Mihyeon,Kim, Seung Tae,Jang, Jiryeon,Rath, Oliver,Schueler, Julia,Lee, Dong Woo,Park, Woong Yang,Kim, Sung Joo,Park, Se Hoon,Lee, Jeeyun Neoplasia Press 2016 Translational oncology Vol.9 No.3

<P><I>BACKGROUND:</I> Although pazopanib treatment has become the standard chemotherapy in salvage setting for metastatic sarcoma patients, most patients progress after pazopanib treatment in 4 to 6 months. After failure to pazopanib, patients have limited options for treatment. Therefore, subsequent therapy in patients who failed to pazopanib is urgently needed and the use of patient derived cells or patient derived tumors for accompanying testing with various pharmacological inhibitors could offer additional treatment options for these patients. <I>METHODS:</I> Patient derived tumor cells were collected from ascites at the time of progression to pazopanib and a 13-drug panel was tested for drug sensitivity. We confirmed the results using <I>in vitro</I> cell viability assay and immunoblot assay. We also performed the genomic profiling of PDX model. <I>RESULTS:</I> The growth of patient derived tumor cells was significantly reduced by exposure to 1.0 μM AZD2014 compared with control (control versus AZD2014, mean growth = 100.0% vs 16.04%, difference = 83.96%, 95% CI = 70.01% to 97.92%, <I>P</I> = .0435). Similarly, 1.0 μM BEZ235 profoundly inhibited tumor cell growth <I>in vitro</I> when compared to control (control versus BEZ235, mean growth = 100.0% vs 7.308%, difference = 92.69%, 95% CI = 78.87% to 106.5%, <I>P</I> < .0001). Despite the presence of CDK4 amplification in the patient-derived tumor cells, LEE011 did not considerably inhibit cell proliferation when compared with control (control vs LEE011, mean growth = 100.0% vs 80.23%, difference = 19.77%, 95% CI = 1.828% to 37.72%, <I>P</I> = .0377). The immunoblot analysis showed that BEZ235 treatment decreased pAKT, pmTOR and pERK whereas AZD2014 decreased only pmTOR. <I>CONCLUSION:</I> Taken together, upregulation of mTOR/AKT pathway in sarcoma patient derived cells was considerably inhibited by the treatment of AZD2014 and BEZ235 with downregulation of AKT pathway (greater extent for BEZ235). These molecules may be considered as treatment option in STS patient who have failed to pazopanib in the context of clinical trials.</P>