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수용성 이성분 혼합용매계에서 치환된 벤젠 술폰산 벤질의 가용매 분해 반응
朴炳端,金永基,柳根宇 順天大學校 1987 論文集 Vol.6 No.1
메탄올, 에탄올, 아세토니트릴, 아세톤 및 THF의 수용성 이성분 혼합용매계어서 네가지 벤젠술폰산 벤젠치환체들의 가용매 분해 반응을 35℃에서 연구하였다. 반응속도는 비양성자성 수용성 혼합용매계에서 보다는 양성자성 수용성 혼합용매계에서 빠름을 알 수 있었으며, 이것은 양성자성 혼합용매계에 의한 친전자성 및 친핵성 보조작용이 전이상태를 안정화시키기 때문이라는 것을 알 수 있었다. 가용매분해반응 속도상수를 Grunwald-Winstein 식, 확장된Grunwald-Winstein 식 및 Hammett식으로 해석하였다. 본 반응의 결과로 부터 비양성자성 수용성 혼합용매계서 용매에 의한 친전자성 보조 작용이 크게 나타남을 알 수 있었다. Solvolysis of four benzyl benzensulfonates have been studied in aqueous methanol,ethanlo,acetonitrile,acetone and tetrahydrofuran mixtures at 35℃. The rates were faster in protic solvent-water mixtures than in aprotic solvent-water mixtures. This was considered in the light of transition state stabilization by electrophilic and nucleophilic solvent assistance of protic solvent mixtures. The rates of solvolysis are analyzed in terms of the Grunwald-Winstein equation, extended Grunwald-Winstein equation and Hammett equation. The results showed that strong electrophilic assistance of solvent is operative in the aprotic solvent-water mixtures.
류근우,유병현 한국지반공학회 2022 한국지반공학회논문집 Vol.38 No.9
Planarity geotechnical exploration missions were actively performed during the 1970s and there was a period of decline from the 1990s to the 2000s because of budget. However, exploring space resources is essential to prepare for the depletion of Earth’s resources in the future and explore resources abundant in space but scarce on Earth, such as rare earth and helium-3. Additionally, the development of space technology has become the driving force of future industry development. The competition among developed countries for exoplanet exploration has recently accelerated for the exploration and utilization of space resources. For these missions and resource exploration/mining, geotechnical exploration is required. There have been several missions to explore exoplanet ground, including the Moon, Mars, and asteroids. There are Apollo, LUNA, and Chang’E missions for exploration of the Moon. The Mars missions included Viking, Spirit/Opportunity, Phoenix, and Perseverance missions, and the asteroid missions included the Hayabusa missions. In this study, space planetary mineral resource exploration technologies are explained, and the future technological tasks of Korea are described.
달에서 인류 활동을 위한 달 현지자원활용(In-Situ Resources Utilization) 기술
류근우(Geunu Ryu),유병현(Byunghyun Ryu) 한국지반환경공학회 2022 한국지반환경공학회논문집 Vol.23 No.12
산업화가 시작된 후 인류는 더 많은 자원을 필요로 하고 소비하며, 현재 자원 고갈은 지구의 심각한 문제이다. 그러나 우주에는 무한한 자원이 존재한다. 특히 달은 지구와 가장 가까운 행성으로 미래 인류에게 필요한 헬륨-3, 희토류 등 많은 자원을 보유하고 있다. 이러한 자원을 채굴하기 위해서는 인류가 달에 상주할 필요가 있다. 그리고 달에 거주하는 인류는 식량, 건축, 산업 자재 등 많은 자원이 필요하다. 그러나 이러한 자원을 지구에서 달까지 운반하려면 천문학적인 비용이 소모되므로 현지에서 자원을 조달하여 인류의 활동을 지원하는 연구가 진행되고 있다. 이를 ISRU(In-Situ Resources Utilization)라고 하며, 이는 우주개발에 필수적이다. 본 논문에서는 ISRU이 필수적인 이유와 그 기술현황을 소개하고 향후 연구과제에 대해 서술하였다. After industrialization has been started, mankind needs and consumes more resources. Now, the resources depletion is a serious problem in the Earth. However, there are infinite resources in the Space. Especially, the Moon is the closest planet and has much resources, including Helium-3 and rare earths, which are needed to human being in the future. Humanity needs to reside on the moon to harvest these resources. For the resident, much resources, such as food, construction, and industrial materials, are needed. However, to transport these resources to the Moon from the Earth, an astronomical cost should be consumed. Thus, research is underway to support human activities by procuring resources locally. This is called In-Situ Resources Utilization (ISRU), which is the essential technology for the space development. In this paper, the reason why ISRU is essential and the its status are introduced and future research projects will be explained.
LEE, IKCHOON,RHYU, KEUN WOO,LEE, HAI WHANG,SHIM, CHANG SUB,OH, HYUCK KEUN 全北大學校 基礎科學硏究所 1991 基礎科學 Vol.14 No.2
Kinetic studies on the reactions of methy1 (MBS) and ethyl benzenesulphonates (EBS) with N, N-dimethylanilines (DMA) in methanol and acetonitrile are reported. The cross interaction constants ρ_XZ and β_XZ, between the substituents in the nucleophile (X) and the leaving group (Z) indicated that the transition states (TS) are looser than those for the reactions with anilines, but the relative tightness between the two substrates was the same; the TS was tighter for EBS despite the increase in steric effect leading to looser TSs for MBS and EBS alike. The TS variation between two different reaction series expected from the simple Hammett and Bronsted coefficients, ρ_X, ρ_Z, β_X and β_Z, was incompatible with that predicted by the cross interaction constants, demonstrating again the unreliability of the simple parameters.
Effects of time-averaged intact parathyroid hormone levels on MACCE in incident dialysis patients
이슬아,류근우,지종현,김형우,박서현,정수영,오형중,박정탁,한승혁,강신욱,유태현 대한내과학회 2015 대한내과학회 추계학술대회 Vol.2015 No.1
Introduction: Chronic kidney disease-mineral bone disorder (CKD-MBD) is known as a major risk factor for increasing cardiovascular disease (CVD) in end-stage renal disease (ESRD) patients. CKD-MBD is classified into low turnover and high turnover bone disease according to the bone dynamics, both of which are related with vascular calcification in ESRD. To evaluate the prognostic value of abnormal serum parathyroid hormone (PTH) levels on ESRD patients, we investigated the effects of time-averaged serum intact PTH (TA-iPTH) levels on overall mortality and major adverse cardiac and cerebrovascular events (MACCEs) in incident dialysis patients. Methods: In this prospective observational study, 413 patients who started dialysis between January 2005 and September 2013 at Yonsei University Health System were enrolled. Patients were divided into three groups according toTA-iPTH levels during the 12 months after initiation of dialysis (group 1: 300 pg/mL). Cox regression analysis was performed to determine the prognostic value of TA-iPTH on overall mortality and MACCEs. Results: The mean age was 56.5±14.5 years and 222 patients (53.8%) were male. During a median follow-up 50.8 months, 49 patients (11.9%) were dead and MACCEs were occurred in 55 patients (13.3%). Multivariate Cox regression analysis demonstrated that low TA-iPTH level was an independent risk factor for both overall mortality [group 2 as reference; group 1, hazard ratio (HR)= 2.08, 95% confidence interval (CI)=1.12-3.85, p=0.02] and MACCEs (HR=1.88, 95% CI=1.04-3.40, p=0.04) in incident dialysis patients after adjusting confounding factors. Conclusions: This study demonstrates that low TA-iPTH is an independent risk factor for overall mortality and MACCEs in incident dialysis patients.