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Lee, K. H.,Kang, S. K.,Goo, J. M.,Lee, J. S.,Cheon, G. J.,Seo, S.,Hwang, E. J. INTERNATIONAL INSTITUTE OF ANTICANCER RESEARCH 2017 Anticancer research Vol.37 No.3
<P>Background/Aim: To compare the relationship between Ktrans from DCE-MRI and K1 from dynamic (NNH3)-N-13- PET, with simultaneous and separate MR/PET in the VX-2 rabbit carcinoma model. Materials and Methods: MR/PET was performed simultaneously and separately, 14 and 15 days after VX-2 tumor implantation at the paravertebral muscle. The Ktrans and K-1 values were estimated using an in-house software program. The relationships between Ktrans and K-1 were analyzed using Pearson's correlation coefficients and linear/non-linear regression function. Results: Assuming a linear relationship, Ktrans and K-1 exhibited a moderate positive correlations with both simultaneous ( r=0.54-0.57) and separate ( r=0.53-0.69) imaging. However, while the Ktrans and K-1 from separate imaging were linearly correlated, those from simultaneous imaging exhibited a non-linear relationship. The amount of change in K-1 associated with a unit increase in Ktrans varied depending on Ktrans values. Conclusion: The relationship between K-trans and K-1 may be mis-interpreted with separate MR and PET acquisition.</P>
K<sub>2</sub>WO<sub>4</sub> flux 에 의한 K<sub>2</sub>Oㆍ6TiO<sub>2</sub> whisker 의 합성
이진식 ( J. S. Lee ),이상문 ( S. M. Lee ),이철태 ( C. T. Lee ),권긍택 ( K. T. Kohn ),김영명 ( Y. M. Kim ) 한국공업화학회 1993 한국공업화학회 연구논문 초록집 Vol.1993 No.0
K<sub>2</sub>Oㆍ6TiO<sub>2</sub> whisker는 구조적인 특성 때문에 물리ㆍ화학적으로 매우 안정하며 보강재, 마찰재, 단열재 등의 많은 용도를 갖게된다. 특히 최근에는 석면이 발암물질로 인한 자동차 브레이크 마찰재료의 사용이 금지됨에 따라 K<sub>2</sub>Oㆍ6TiO<sub>2</sub> whisker는 이의 대체 섬유로서 주목을 받고 있다. 이러한 K<sub>2</sub>Oㆍ6TiO<sub>2</sub> whisker의 합성방법으로는 TiO<sub>2</sub>와 K<sub>2</sub>CO<sub>3</sub>의 화학양론적 조성의 혼합들을 설정온도에서 소성(calcination method)시키는 방법을 비롯하여 응용법(melting method), 수열법(hydrothermal method), 융제법(flux) 및 KDC법(kneading-drying-calcination method) 등의 방법이 있다. 그러나 수열법의 경우 양질의 whisker를 얻을 수 있으나 고압합성 이므로 위험하고 가격이 비싼 결점이 있으며 공업상 제조에 필요한 조건이 복잡하고 연속조작이 어려워 비현실적인 방법이다. 또한 서냉소성법의 경우 공정이 단순하며 공업화가 쉬우나 비교적 장섬유가 얻어지게 된다. 따라서 본 연구에서는 융제법을 이용하여 K<sub>2</sub>Oㆍ6TiO<sub>2</sub> whisker를 합성하였으며. 과거에 용제로 사용된 KC1-KF계. K<sub>2</sub>O-Na<sub>2</sub>O-B<sub>2</sub>O<sub>3</sub>계 등의 높은 volatility와 viscosity 그리고 낮은 solubility에 대한 문제점을 개선하기 위해 K<sub>2</sub>WO<sub>4</sub>를 flux로 선정하여 K<sub>2</sub>Oㆍ6TiO<sub>2</sub> whisker를 합성하였다.
Stoichiometric Layered Potassium Transition Metal Oxide for Rechargeable Potassium Batteries
Kim, Haegyeom,Seo, Dong-Hwa,Urban, Alexander,Lee, Jinhyuk,Kwon, Deok-Hwang,Bo, Shou-Hang,Shi, Tan,Papp, Joseph K.,McCloskey, Bryan D.,Ceder, Gerbrand American Chemical Society 2018 Chemistry of materials Vol.30 No.18
<P>K-ion batteries are promising alternative energy storage systems for large-scale applications because of the globally abundant K reserves. K-ion batteries benefit from the lower standard redox potential of K/K<SUP>+</SUP> than that of Na/Na<SUP>+</SUP> and even Li/Li<SUP>+</SUP>, which can translate into a higher working voltage. Stable KC<SUB>8</SUB> can also be formed via K intercalation into a graphite anode, which contrasts with the thermodynamically unfavorable Na intercalation into graphite, making graphite a readily available anode for K-ion battery technology. However, to construct practical rocking-chair K-ion batteries, an appropriate cathode material that can accommodate reversible K release and storage is still needed. We show that stoichiometric KCrO<SUB>2</SUB> with a layered O3-type structure can function as a cathode for K-ion batteries and demonstrate a practical rocking-chair K-ion battery. In situ X-ray diffraction and electrochemical titration demonstrate that K<SUB><I>x</I></SUB>CrO<SUB>2</SUB> is stable for a wide K content, allowing for topotactic K extraction and reinsertion. We further explain why stoichiometric KCrO<SUB>2</SUB> is unique in forming the layered structure unlike other stoichiometric K-transition metal oxide compounds, which form nonlayered structures; this fundamental understanding provides insight for the future design of other layered cathodes for K-ion batteries.</P> [FIG OMISSION]</BR>
Urea와 K<sub>2</sub>SO<sub>4</sub> 처리에 의한 복숭아 '미백도'에서 수확 시 과실의 무기성분 농도 및 과피색 변화
문병우,윤익구,문영지,남기웅,이영철,Moon, B.W.,Yoon, I.K.,Moon, Y.J.,Nam, K.W.,Lee, Y.C. 국립한국농수산대학교 교육개발센터 2013 현장농업연구지 = Journal of practical agricultural resear Vol.15 No.1
This study has been conducted to investigate the effect of Urea and K<sub>2</sub>SO<sub>4</sub> treatment at stone hardening stage and 20 days before harvest on soil chemical properties, mineral nutrient concentration and quality of 'Mibaekdo' fruit peach. K concentration after Urea and K<sub>2</sub>SO<sub>4</sub> treatment in soil was increased significantly by Urea 162g+K<sub>2</sub>SO<sub>4</sub> 188g/tree(standard amount) treatment at stone hardening stage, K<sub>2</sub>SO<sub>4</sub> 1.0% tree-spray, Urea 81g+K<sub>2</sub>SO<sub>4</sub> 94g/tree(half amount), Urea 162g+K<sub>2</sub>SO<sub>4</sub> 188g/tree and Urea 324g+K<sub>2</sub>SO<sub>4</sub> 376g/tree(double amount) soil treatment before harvest 20 days compared to control. T-N, K and Ca concentration in leaf was increased significantly by all treatment. but Na concentration in leaf was increased by Urea 0.5% and K<sub>2</sub>SO<sub>4</sub> 1.0% tree-spray treatment before harvest 20 days. T-N concentration in fruit skin was increased significantly by standard amount soil treatment, which decreased by K<sub>2</sub>SO<sub>4</sub> 1.0% tree-spray and half amount soil treatment. T-N, K and Ca concentration in fruit flesh(1~10mm depth flesh from peel) were increased markedly by all treatment excepted Urea 0.5% tree-spray. The leaf weight at harvest was increased markedly by Urea 0.5% tree-spray, standard amount and double amount treatment before harvest 20 days. Fruit weight was increased significantly by standard amount compared to all treatment. Red fruit skin(Hunter a value) progress was effective by K<sub>2</sub>SO<sub>4</sub> tree-spray, half amount and double amount treatment before harvest 20 days. Fruit SSC was increased significantly by Urea 0.5% and K<sub>2</sub>SO<sub>4</sub> tree-spray before harvest 20 days, standard amount treatment at stone hardening stage compared to control.
1H NMR Measurements of the Phase Transition of (NH₄)₃H(SO₄)₂ Single Crystals
S. H. Choi,Moohee Lee,Ae Ran Lim,K. S. Han,S. K. Kwon,S. K. Nam 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.2
$^1$H nuclear magnetic resonance (NMR) experiments have been performed in the temperature range of 30 -- 300 K at 7 T to investigate the phase-dependent nature of the dynamic network of hydrogen bonds in a ((NH₄)₃H(SO₄)₂ single crystal. The crystal has six phases, which are ferroelectric, antiferroelectric, incommensurate, antiferroelectric, ferroelastic, and superionic with the respective transition temperatures of 63, 133, 139, 256 and 413 K. The spin-lattice relaxation time, T₁, of ¹H NMR is similar for the ammonium protons and the hydrogen-bond protons over the entire range of experimental temperatures. The T₁, of ¹H NMR gradually decreases down to 120 K and starts to steeply increase below 100 K. Then, the T₁ shows an abrupt decrease below 68 K with a sharp minimum at 63 K, where the ferroelectric transition occurs. The ¹H NMR spectrum shifts to the high-frequency side at temperatures below 63 K due to the ferroelectric phase transition. This behavior of the T₁ and the spectrum confirms a dramatic change in the dynamics of hydrogen bonds associated with the ferroelectric phase transition at 63 K. $^1$H nuclear magnetic resonance (NMR) experiments have been performed in the temperature range of 30 -- 300 K at 7 T to investigate the phase-dependent nature of the dynamic network of hydrogen bonds in a ((NH₄)₃H(SO₄)₂ single crystal. The crystal has six phases, which are ferroelectric, antiferroelectric, incommensurate, antiferroelectric, ferroelastic, and superionic with the respective transition temperatures of 63, 133, 139, 256 and 413 K. The spin-lattice relaxation time, T₁, of ¹H NMR is similar for the ammonium protons and the hydrogen-bond protons over the entire range of experimental temperatures. The T₁, of ¹H NMR gradually decreases down to 120 K and starts to steeply increase below 100 K. Then, the T₁ shows an abrupt decrease below 68 K with a sharp minimum at 63 K, where the ferroelectric transition occurs. The ¹H NMR spectrum shifts to the high-frequency side at temperatures below 63 K due to the ferroelectric phase transition. This behavior of the T₁ and the spectrum confirms a dramatic change in the dynamics of hydrogen bonds associated with the ferroelectric phase transition at 63 K.