http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Probing Electronic Structures of Melts and Glasses under Compression
Sung Keun Lee(이성근),Sun Young Park(박선영),Yoo Soo Yi(이유수),Eun Jeong Kim(김은정),Yong-Hyun Kim(김용현),Hyo-Im Khim(김효임),A Chim Lee(이아침),Saebom Ryu(류새봄),Hoon Khim(김훈),Kwan Young Mun(문관영),Juho Lhee(이주호) 한국암석학회 2020 한국암석학회 학술발표회 논문집 Vol.2020 No.8
Jeong-Eun Lee(이정은),Seung-Hyeon Song(송승현),Ji-U Ha(하지우),Hyo-Ri Kim(김효리),Chang-Soon Lee(이창순),In-Sik Cho(조인식) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11
The elastic modulus and Poissons ratio have been measured by the tensile test with the attachment of gauge sensors. However, the simpler dynamic method has been developed by using the acoustic resonance frequency, which is much easier and more accurate than the conventional tensile test. The typical dynamic methods are (i) the Ultrasonic pulse echo method, (ii) the Resonance frequency method, and (iii) the Impulse Excitation Method. Although both the Ultrasonic echo method and the resonance frequency method have widely been used, the Impulse Excitation Method has come into the spotlight due to its simplicity and accuracy, which has also been prescribed in ASTM E1876. In this study, the practical control system has been implemented with the numerical analysis algorithm for the Impulse Excitation Method. With this technique, the dynamic elastic modulus and Poissons ratio have been measured and evaluated for structural materials such as Al7075-T6, STS304, STS420_J2, SCM440, STS630 and Ti6Al4V. Therefore, the reliability was verified through comparative evaluation of the results of the static test method and the dynamic test method for six structural materials.
찰옥수수 연구 : ⅩⅢ. 다수성 찰옥수수 "대덕찰 1호"의 주요 작물학적 특성 및 경제성 분석
이희봉(Hee-Bong Lee),이문섭(Moon-Sub Lee),복태규(Tae-Gyu Bok),최윤표(Yun-Pyo Choi),차희정(Hui-Jung Cha),홍범용(Bum-Yong Hong),김효기(Hyo-Gi Kim) 충남대학교 농업과학연구소 2011 농업과학연구 Vol.38 No.1
Daeduckchal 1 waxy corn hybrid including check was planted and compared with domestic leading vatiety on agronomic characteristics, traits related to table gualities and crude income. Stem and ear height of Daeduckchal 1 among used hybrids were intermediate and stem diameter was also similar to other hybrids. Days to tasseling of this hybrid needed 56 days which was slightly shorter than check hybrid, Yeonnong. Ear length of CNU-H2 was longer than Yeonnongchal as 21.7 ㎝, while Chalok 2 was 14.1 ㎝. Number of tillers per plant of this hybrid were higher than Chalok 2 but lower than Yeonnong. Pericarp thickness of CNU-H2 and CNU-H3 were similar to Yeonnon. In sugar content, Daeduckchal 1 was intermediate level as 11.7 brix(%). Marketability of Daeduckchal 1 was the highest among used hybrids and crude incomes was also high.
비정질 알칼리 규산염 원자구조의 철 함량 효과에 관한 고체 NMR 분광학 연구
김효임 ( Hyo Im Kim ),이성근 ( Sung Keun Lee ) 한국광물학회 2011 광물과 암석 (J.Miner.Soc.Korea) Vol.24 No.4
철을 포함한 비정질 규산염 용융체의 원자 구조 규명은 지표 환경의 화성활동 및 맨틀 심부의 초저속도층의 속도구조에 이르는 광범위한 지질과정의 미시적인 원인에 대한 단서를 제공한다. 본 연구에서는 철을 포함한 비정질 규산염의 원자 구조 규명에 가장 적합한 고상 핵자기공명분광분석(NMR)을 이용하여 최대 16.07 wt%의 Fe2O3가 포함된 비정질 알칼리 규산염(iron-bearing alkali silicate glasses)의 철의 함량 변화가 원자구조에 미치는 영향을 규명하였다. 29Si 스핀-격자 완화시간(T1)을 측정한 결과, 철의 함량에 따라 스핀-격자 완화시간이 짧아지는데 이는 철이 가지고 있는 홀전자(unpaired electron)와 핵 스핀(nuclear spin)간의 상호작용으로부터 기인한다. 29Si MAS NMR 실험 결과, 철이 포함되지 않은 시료의 경우 Q2, Q3 그리고 Q4의 환경을 지시하는 피크가 분리됨에 반하여, 철이 포함된 시료의 경우 NMR 신호의 급격한 감소와 피크 폭이 넓어짐으로써 각각의 규소 환경이 거의 분리되지 않았다. 그러나 철의 함량에 따라 스펙트럼이 넓어지고 화학적 차폐값(chemical shift)이 높아지는 현상을 확인하였는데, 이는 Q4의 규소 환경을 나타내는 방향으로서 철 주변의 Qn이 불균질하게 분포하고 있음을 지시한다. 17O MAS NMR 실험에서도 철이 포함되지 않은 시료에서는 연결산소(Si-O-Si)와 비연결산소(Na-O-Si)가 부분적으로 분리되지만, 철의 함량이 증가하면서 각각의 산소환경이 거의 분리되지 않는다. 이러한 연구결과는 고상 핵자기공명분광분석이 철을 포함한 비정질 규산염의 상세한 구조 연구에 효과적인 도구임을 지시한다. The study on the atomic structure of iron-bearing silicate glasses has significant geological implications for both diverse igneous processes on Earth surface and ultra-low velocity zones at the core-mantle boundary. Here, we report experimental results on the effect of iron content on the atomic structure in iron-bearing alkali silicate glasses (Na2O-Fe2O3-SiO2 glasses, up to 16.07 wt% Fe2O3) using 29Si and 17O solid-state NMR spectroscopy. 29Si spin-lattice (T1) relaxation time for the glasses decreases with increasing iron content due to an enhanced interaction between nuclear spin and unpaired electron in iron. 29Si MAS NMR spectra for the glasses show a decrease in signal intensity and an increase in peak width with increasing iron content. However, the heterogeneous peak broa-dening in 29Si MAS NMR spectra suggests the heterogeneous distribution of Qn species around iron in iron-bearing silicate glasses. While nonbridging oxygen (Na-O-[4]Si) and bridging oxygen ([4]Si-O-[4]Si) peaks are partially resolved in 17O MAS NMR spectrum for iron-free silicate glass, it is difficult to distinguish the oxygen clusters in iron-bearing silicate glass. The Lorentzian peak shape for 29Si and 17O MAS NMR spectra may reflect life-time broadening due to spin-electron interaction. These results demonstrate that solid-state NMR can be an effective probe of the detailed structure in iron-bearing silicate glasses.