• 대한기계학회논문집A
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• 제30권9호
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• pp.1034-1040
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• 2006

Due to the need of increasing thermal efficiency, supercritical pressure and temperature have been utilized in power plants. It is well known that 9Cr1Mo steel is suitable fer use in power plants operating at supercritical conditions. Therefore, to ensure the safety and the soundness of the power plant, creep characterization of the steel is important. In this study, the creep characterization of the gCr1Mo steel using small punch creep(SP-Creep) test has been described. The applied load and the central displacement of the specimen in SP-Creep test have been converted to bearing stress and strain of uc, respectively. The converted SP-Creep curves clearly showed the typical three-stage behavior of creep. The steady-state creep rate and the rupture time of the steel logarithmically changed with the bearing stress and satisfied the Power law relationship. Furthermore, the Larson-Miller parameter of the SP-Creep test agreed with that of the tensile creep test. From the comparison with low Cr-Mo steels, the creep characteristics of 9Cr1Mo steel proved to be superior. Thus, it can be confirmed that the 9Cr1Mo steel is suitable for supercritical power plant.

• 한국약용작물학회지
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• 제14권1호
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• pp.19-22
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• 2006

작약은 다년생 숙근성으로 가을에 식재가 일반적이지만 식재시기를 놓치거나 토지의 이용, 농가의 사정 등으로 부득이 봄에 식재 할 경우 생육과 뿌리수량에 미치는 영향에 대하여 시험한 결과는 다음과 같다. 식재 당년 맹아의 출현은 봄 식재시기가 늦을수록 빨라졌다. 생육은 3월 10일에 식재한 것이 가장 양호하여 키가 크고 줄기수가 많았으며 뿌리의 길이와 수 및 굵기도 증대되었다. 4월 10일에 식재한 것은 생육중 고사로 결주가 24% 발생하였고 생육이 불량하였으며 뿌리 수량은 3월 10일 식재에 비하여 43% 수준으로 크게 저조하였다. 2년생 10g당 건근수량은 3월10일 식재가 635 kg으로 가장 많았으며 2월 25일과 3월 25일은 비슷하였고 4월 10일 식재는 359 kg으로 가장 적어 작약 봄식재 시기는 언땅이 풀린 후부터 3월 10일 경이 가장 적합하였다. 작약의 주성분인 Paeoniflorin함량은 봄식재시기 간에 유의성이 없었다.

• International Journal of Stem Cells
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• 제10권1호
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• pp.1-11
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• 2017

Human cardiomyocytes (CMs) cease to proliferate and remain terminally differentiated thereafter, when humans reach the mid-20s. Thus, any damages sustained by myocardium tissue are irreversible, and they require medical interventions to regain functionality. To date, new surgical procedures and drugs have been developed, albeit with limited success, to treat various heart diseases including myocardial infarction. Hence, there is a pressing need to develop more effective treatment methods to address the increasing mortality rate of the heart diseases. Functional CMs are not only an important in vitro cellular tool to model various types of heart diseases for drug development, but they are also a promising therapeutic agent for cell therapy. However, the limited proliferative capacity entails difficulties in acquiring functional CMs in the scale that is required for pathological studies and cell therapy development. Stem cells, human pluripotent stem cells (hPSCs) in particular, have been considered as an unlimited cellular source for providing functional CMs for various applications. Notable progress has already been made: the first clinical trials of hPSCs derived CMs (hPSC-CMs) for treating myocardial infarction was approved in 2015, and their potential use in disease modeling and drug discovery is being fully explored. This concise review gives an account of current development of differentiation, purification and maturation techniques for hPSC-CMs, and their application in cell therapy development and pharmaceutical industries will be discussed with the latest experimental evidence.

• 한국문헌정보학회지
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• 제53권4호
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• pp.341-359
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• 2019

연구 생산성의 향상을 위해서는 최신의 정보를 빠르게 습득하는 것이 무엇보다 중요하다. 이를 위해 연구자들은 다양한 경로와 방법으로 정보 자원을 찾고 이를 연구개발 과정에서 활용하고 있다. 한국과학기술정보연구원(KISTI)에서 연구정보 생태계를 지원하기 위해 사이언스온(ScienceOn)이라는 과학기술 지식인프라 통합서비스를 개발하여 전문정보를 비롯하여 인프라 자원, 산업 및 기술 분석 자원들을 한곳에서 제공하고 있다. 이를 통해 다양한 정보와 서비스들의 연계와 융합을 통한 접근성과 활용성을 높여주고 있다. 본 연구에서는 과학기술 학술정보 통합서비스에 대한 최근 연구개발 동향과 과학기술 지식인프라들을 분석하여 이용 목적에 따라 묶음 형태로 활용이 가능한 추천 패키지서비스를 제안하였다. 과학기술 학술정보에 대한 연계 및 융합서비스를 통한 국가 R&D 생산성 향상을 기대해 본다.

• 대한정형외과학회지
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• 제53권6호
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• pp.459-465
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• 2018

정형외과 수술의 임상적 결과에 영향을 미치는 요소는 여러 가지가 있지만 수술적 수기가 가장 중요한 요인이며 로봇공학은 술기를 보다 정확하고 일관되게 수행하기 위해 도입되었다. 정형외과 영역에서는 20년 전부터 로봇수술을 사용하였으나 실용성 문제와 합병증의 발생으로 일부 로봇은 도태되었으며 단점을 개선한 로봇이 소개되고 있다. 대부분의 로봇수술은 인공관절수술 분야에서 시행되었고 치환물의 정렬과 위치 선정에서 우수한 것으로 보고되고 있다. 그러나 임상적 결과의 우수성, 실용성, 가성비 등의 측면에서 제한점이 있고 일부 로봇수술에서는 합병증 발생 빈도가 높다는 보고가 있었다. 초기 로봇수술은 수술자의 개입 없이 계획된 수술이 진행되는 능동형 로봇수술이 주를 이루었으나 최근에는 수술과정에서 실시간 피드백을 통해 술자가 술 전 계획을 변경할 수 있고, 햅틱 경계 내에서 제한된 골절제를 함으로써 주요 혈관, 신경, 인대 등의 손상을 최소화할 수 있는 반능동형 로봇수술이 소개되고 있다.

• Advances in environmental research
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• 제9권4호
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• pp.233-249
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• 2020

To date, there is no central wastewater (WW) treatment plant in Erbil city, Kurdistan region, Iraq. Therefore, raw WW disposes to the environment and sometimes it used directly for irrigation in some areas of Erbil city. Disposal of the untreated WW to the natural environment and using for irrigation it causes problems for the people and the environment. The aims of the current work were to study the characteristics, design of primary and different secondary treatment units and reusing of produced WW. Raw WW samples from Ashty city-Erbil city were collected and analyzed for twenty three quality parameters such as Total Suspended Solids (TSS), total dissolved solids, total volatile and non-volatile solids, total acidity, total alkalinity, total hardness, five-day Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), biodegradability ratio (BOD5/COD), turbidity, etc. Results revealed that some parameters such as BOD5 and TSS were exceeded the standards for disposal of WW. Design and calculations for primary and secondary treatment (biological treatment) processes were presented. Primary treatment units such as screening, grit chamber, and flow equalization tank were designed and detailed calculation were illustrated. While, Conventional Activated Sludge (CAS), Sequencing Batch Reactor (SBR) and Moving Bed Biofilm Reactors (MBBR) were applied for the biological treatment of WW. Results revealed that MBBR was the best and economic technique for the biological treatment of WW. Treated WW is suitable for reusing and there is no restriction on use for irrigation of green areas inside Ashty city campus.

• 대기
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• 제32권2호
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• pp.149-162
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• 2022

This study investigated the prediction skill of the Asian dust seasonal forecasting model (GloSea5-ADAM) on the Asian dust and meteorological variables related to the dust generation for the period of 1991~2016. Additionally, we evaluated the prediction skill of those variables depending on the combination of the initial dates in the sub-seasonal scale for the dust source region affecting South Korea. The Asian dust and meteorological variables (10 m wind speed, 1.5 m relative humidity, and 1.5 m air temperature) from GloSea5-ADAM were compared to that from Synoptic observation and European Centre for medium range weather forecasts reanalysis v5, respectively, based on Mean Bias Error (MBE), Root Mean Square Error (RMSE), and Anomaly Correlation Coefficient (ACC) as evaluation criteria. In general, the Asian dust and meteorological variables in the source region showed high ACC in the prediction scale within one month. For all variables, the use of the initial dates closest to the prediction month led to the best performances based on MBE, RMSE, and ACC, and the performances could be improved by adjusting the number of ensembles considering the combination of the initial date. ACC was as high as 0.4 in Spring when using the closest two initial dates. In particular, the GloSea5-ADAM shows the best performance of Asian dust generation with an ACC of 0.60 in the occurrence frequency of Asian dust in March when using the closest initial dates for initial conditions.

• Communications for Statistical Applications and Methods
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• 제29권1호
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• pp.85-101
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• 2022

Derivative-linked securities (DLS) is a type of derivatives that offer an agreed return when the underlying asset price moves within a specified range by the maturity date. The underlying assets of DLS are diverse such as interest rates, exchange rates, crude oil, or gold. A German 10-year bond rate-linked DLS and a USD-GBP CMS rate-linked DLS have recently become a social issue in Korea due to a huge loss to investors. In this regard, this paper accounts for the payoff structure of these products and evaluates their prices and fair coupon rates as well as risk measures such as Value-at-Risk (VaR) and Tail-Value-at-Risk (TVaR). We would like to examine how risky these products were and whether or not their coupon rates were appropriate. We use Hull-White Model as the stochastic model for the underlying assets and Monte Carlo (MC) methods to obtain numerical results. The no-arbitrage prices of the German 10-year bond rate-linked DLS and the USD-GBP CMS rate-linked DLS at the center of the social issue turned out to be 0.9662% and 0.9355% of the original investment, respectively. Considering that Korea government bond rate for 2018 is about 2%, these values are quite low. The fair coupon rates that make the prices of DLS equal to the original investment are computed as 4.76% for the German 10-year bond rate-linked DLS and 7% for the USD-GBP CMS rate-linked DLS. Their actual coupon rates were 1.4% and 3.5%. The 95% VaR and TVaR of the loss for German 10-year bond rate-linked DLS are 37.30% and 64.45%, and those of the loss for USD-GBP CMS rate-linked DLS are 73.98% and 87.43% of the initial investment. Summing up the numerical results obtained, we could see that the DLS products of our interest were indeed quite unfavorable to individual investors.

• Journal of Veterinary Science
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• 제21권4호
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• pp.63.1-63.9
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• 2020

Background: Canine adenovirus type 2 (CAV-2) induces infectious laryngotracheitis in members of the family Canidae, including dogs. To date, no ELISA kits specific for CAV-2 antibody have been commercialized for dogs in Korea. Objectives: We aimed to develop new indirect enzyme-linked immunosorbent assay (I-ELISA) to perform rapid, accurate serological surveys of CAV-2 in dog serum samples. Methods: In total, 165 serum samples were collected from dogs residing in Chungbuk and Gyeongbuk provinces between 2016 and 2018. The Korean CAV-2, named the APQA1701-40P strain, was propagated in Madin-Darby canine kidney cells and purified in an anion-exchange chromatography column for use as an antigen for I-ELISA. The virus-neutralizing antibody titers of CAV-2 in the dog sera were measured by virus neutralization (VN) test. Results: We compared the results obtained between the VN and new I-ELISA tests. The sensitivity, specificity, and accuracy of new I-ELISA were 98.6%, 86.4% and 97.0% compared with VN test, respectively. New I-ELISA was significantly correlated with VN (r = 0.91). Conclusions: These results indicate that new I-ELISA is useful for sero-surveillance of CAV-2 in dog serum.

• 한국임상약학회지
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• 제33권1호
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• pp.8-21
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• 2023

Background: Gastrointestinal (GI) drugs are often co-prescribed with other medications to prevent GI complications. This study aimed to evaluate the prescribing pattern of potentially unnecessary GI drugs in patients with acute cystitis who were prescribed oral antibiotics and investigate the influencing factors affecting this. Methods: We identified female patients ≥20 years with acute cystitis who visited the outpatient clinic and were prescribed oral antibiotics between July and December by analyzing Health Insurance Review and Assessment Service (HIRA)-National Patients Sample (NPS)-2019 data. Patients with no prior history of GI disorders within 180 days prior to acute cystitis, excluding or including the date of diagnosis of acute cystitis, were selected (Group A and B). Multiple logistic regression analysis was performed to estimate the factors affecting the prescription of potentially unnecessary GI drugs. Results: A total of 1,544 in Group A and 552 patients in Group B were included for the final analysis. Potentially unnecessary GI drugs were prescribed in 1,176 patients in Group A (76.2%) and 231 patients in Group B (41.8%). Third generation cephalosporines and sulfonamides showed the lower odds ratio for prescribing GI drugs than penicillins. Prescribers from Urology clinics showed more than twice odds ratio for the prescription of GI drugs compared to prescribers from internal medicine clinics. Conclusion: The results of this study showed that potentially unnecessary GI drug prescriptions for patients with acute cystitis were high in South Korea. The positive risk factors affecting the prescription of unnecessary GIs were not patient-related factor but healthcare facility and prescriber-related factors.