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        • KCI등재

          [ $^1H$ ] Nuclear Magnetic Resonance Study of Ferroelectric $(NH_4)_3H(SO_4)_2$

          Choi,,S.H.,Han,,K.S.,Kwon,,S.K.,Nam,,S.K.,Choi,,H.H.,Lee,,Moo-Hee,Lim,,Ae-Ran Korean Magnetic Resonance Society 2007 Journal of the Korean Magnetic Resonance Society Vol.11 No.2

          [ $^1H$ ] nuclear magnetic resonance (NMR) experiments have been performed at 30 - 300 K and 7 T to investigate dynamics of hydrogen bond network in the single crystal $(NH_4)_3H(SO_4)_2$. The two proton sites, ammonium proton and hydrogen-bond proton, are identified from the $^1H$ NMR MAS spectrum at 340 K. As temperature decreases, the $^1H$ NMR spectrum shifts to the higher frequency side with a larger linewidth. The spectrum at 65 K shows a distinctive change in line shape toward the ferroelectric transition at 63 K. The measured values of $T_1$ for ammonium and hydrogen-bond protons are similar in the whole range of temperature. $T_1$ of $^1H$ NMR shows a gradual decrease down to 120 K and starts to steeply increase below 100 K. Then $T_1$ shows abrupt decrease below 70 K with a sharp minimum at 63 K, where the ferroelectric transition occurs. This temperature dependence of spectrum and $T_1$ clearly prove that the large change in the dynamics of hydrogen bond network is associated with the ferroelectric phase transition at 63 K.

        • SCOPUSKCI등재

          K - 통로개방제가 배양심근세포와 생쥐 체내의 Thallium - 201 역동학에 미치는 영향

          김은지,하정희,이재태,이규보,안병철,손상균,김천기 대한핵의학회 1996 핵의학 분자영상 Vol.30 No.4

          Background: Potassium channel opener (K-opener) opens ATP-sensitive K+-channel located at membrane and induces potassium efflux from cytosol, resulting in intracellular hyperpolarization. Newly synthesized K-opener is currently examined for pharmacologic potency by means of rubidium release test from smooth muscle strip pre-incubated with Rb-86. Since in-vive behavior of thallium is similar to that of rubidium, we hypothesized that K-opener can alter T1-201 kinetics in vivo. Purpose: This study was prepared to investigate the effects of pinacidil (one of potent K-openers) on the T1-201 uptake and clearance in cultured myocyte, and in-vivo biodi- stribution in mice. Methods: Spontaneous contracting myocytes were prepared to imitate in-vivo condition from 20 hearts of 3-5 days old Sprague-Dawley rat and cultured for 3-5 days before use (5×105 cells/ml). Pinacidil was dissolved in 10% DMSO solution at a final concentration of 100nM or 10uM and was co-incubated with T1-201 in HBSS buffer for 20-min to evaluate is effect on cellular T1-uptake, or challenged to cell preparation pre-incubated with T1-201 for washout study. Two, 40 or 100μg of pinacidil was injected intravenously into ICR mice at 10 min after 5μCi T1-201 injection, and organ uptake and whole body retention rate were measured at different time points. Results: Co-incubation of pinacidil with T1-201 resulted in a decrease in T1-201 uptake into cultured myocyte by 1.6 to 2.5 times, depending on pinacidil concentration and activity of T1-201 used. Pinacidil enhanced T1-201 washout by 1.6-3.1 times from myocyte preparations pre-incubated with T1-201. Pinacidil treatment appears to be resulted in mild decreases in blood and liver activity in normal mice, in contrast, renal and cardiac uptake were mildly decreased in a dose dependent manner. Whole body retention ratios of T1-201 were lower at 24 hour after injection with 100μg of pinacidil than control. Conclusion: These results suggest that treatment with K-opener may affect the interpretation of T1-201myodial images, due to decreasing thallium accumulation and enhancing washout from myocardium.

        • KCI등재

          강섬유보강 고강도콘크리트를 적용한 최상층 접합부의 내진성능 평가

          김상희(Sang-Hee Kim), 권병운(Byung-Un Kwon), 강현구(H.-K. Kang) 한국콘크리트학회 2016 콘크리트학회논문집 Vol.28 No.2

          본 논문에서는 고강도콘크리트와 SD600 철근을 적용한 특수모멘트골조의 최상층 접합부 내진성능을 파악하고자 한다. 실험체 중 K-RC-H는 내진규정에 따라 제작되었으며, K-HPFRC-H에는 횡보강근 간격을 150%로 증가시키면서 대신 강섬유를 부피비 1.0% 혼입하였다. K-RC-H, K-HPFRC-H 실험체 모두 주근이 파단하기 이전까지 내력 저하가 거의 없었고 에너지 소산능력 등에서 우수한 내진성능을 보였다. 접합부내의 U-bar는 보 주근이 휨과 함께 인장력을 받을 때 상부면으로 밀어내려는 현상을 충분히 억제하는 것으로 나타났다. 한편 SD600의 정착길이는 1.25ldt가 확보되었는데 슬립거동이 거의 발생하지 않았다. 전반적으로 강섬유의 혼입은 휨강도 증가, 전단변형각 구속력 향상 등에 기여하였고, 강섬유 혼입률 1.0% 혼입함으로써 횡보강근 간격을 1.5배 증가시킬 수 있는 가능성을 실험적으로 확인하였다. This study was conducted to verify seismic performance of special moment frame"s joints at roof-level with high-strength concrete and SD600 bars. K-RC-H was designed according to the seismic code and K-HPFRC-H had 150% of the original hoop spacing and 1.0% steel fiber volume fraction compared with K-RC-H. Both specimens had remarkable seismic performance without noticeable decrease in moment, but with very good energy dissipation before rebar failure. The U-bars in the joint sufficiently constrained rebar`s action that pushed the cover upward. SD600 bars with 1.25ldt had minimum slip in the joint. It was considered that the steel fiber contributed to improvement of the bending moment and joint shear distortion, and the result showed that it would be possible to increase the hoop spacing to 150% of the regular spacing.

        • KCI등재

          Novel Linking Ligand Containing Sulfur-Donor Atoms and Its Compounds of Palladium and Silver

          Hee,K.,Lee,이순원 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.3

          A linking ligand containing sulfur donor atoms in the terminal thiophene rings, 1,2-bis(thiophen-2-ylmethylene)hydrazine (L), was prepared by Schiff-base condensation. Ligand L reacted with [PdCl2(NCPh)2] to produce a molecular Pd compound [PdL2Cl2] (1). On the other hand, it reacted with AgNO3 and AgClO4 to produce a 2-D network [AgL0.5(NO3)] (2) and a 1-D polymer [AgL]ClO4 (3), respectively, whose structures are based on secondary intermolecular forces such as H-bonding, van der Waals interaction, and p-p stacking. Polymer 2 exhibited photoluminescence at room temperature in the solid state.

        • KCI등재

          Evaluation of Cytotoxicity, Antimicrobial and Antioxidant Enzyme Activity of Diploid and Tetraploid Platycodon grandiflorum

          Hee-Ock,Boo,Young-Sun,Kim,Hag-Hyun,Kim,Soo-Jeong,Kwon,Sun-Hee,Woo 한국작물학회 2015 Korean journal of crop science Vol.60 No.2

          This experiment was conducted to obtain the have higher contents of pharmaceutical constituents as well as higher yield from colchicine induced diploid and tetraploid extracts of Platycodon grandiflorum. In order to determine the biological activity, this study was focused to evaluate the cytotoxicity, antimicrobial on the bronthus disease bacteria, antioxidant enzyme activity of diploid and tetraploid extracts in P. grandiflorum. The activities of antioxidant enzyme according to different solvent extracts were measured as superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX). The cytotoxicity of methanol extracts of P. grandiflorum showed significant differences between tetraploid and diploid. That is, the cytotoxic effect against human cancer cell was higher in tetraploid than in diploid. At all extracts concentration, tetraploid samples showed high toxicity and the IC50 (concentration causing 50% cell death) value showed the highest on HCT-116 cell (105.91 μg/mL), and exhibited significant activity against the Hep 3B cell (140.67 μg/mL), SNU-1066 cell (154.01 μg/mL), Hela cell (158.37 μg/mL), SNU-601 cell (182.67 μg/mL), Calu-6 cell (190.42 μg/mL), MCF-7 cell (510.19 μg/mL). Antimicrobial activities of diploid P. grandiflorum were relatively low compared to tetraploid P. grandiflorum on most of the bacterial strains. In tetraploid P. grandiflorum, K. pneumoniae showed the clear zone formation (18~19 mm) of growth inhibition, followed by the clear zone formation of 13~15 mm on C. diphtheria and S. pyogenes. The antimicrobial activities in diploid P. grandiflorum were the highest on K. pneumonia (14~15 mm), and showed the clear zone formation of 11~12 mm on C. diphtheria and 12~13 mm on S. pyogenes. The antimicrobial activity is thought to look different depending on the bacterial strains and the polyploidy of P. grandiflorum. The root extract of P. grandiflorum had the highest (97.2%) SOD enzyme activity in ethyl acetate partition layer of tetraploid while water partition layer of diploid showed the lowest (48.6%) SOD enzyme activity. The activity of CAT showed higher values in the root of tetraploid than in the diploid of P. grandiflorum in all partition layers except butyl alcohol. The activities of APX and POD showed higher values in the root of tetraploid than in the diploid of P. grandiflorum in all fraction solvents except water layer. These results indicate that the tetraploid P. grandiflorum can be used as a source for developing cytotoxic agent and antimicrobials which can act against bronchus diseases bacterial strains.

        • KCI등재후보SCOPUS

          Piggery Slurry Composting Using Batch Operating Autothermal Thermophilic Aerobic Digestion System

          Hee,K.,Ahn,최홍림 아세아·태평양축산학회 2006 Animal Bioscience Vol.19 No.2

          The performance of an autothermal thermophilic aerobic digestion (ATAD) system was studied to determine if nitrogen loss, as ammonia, was affected by an exhaust gas condenser. The system was run with and without a condenser while treating 8 m3 of piggery slurry for 8 days. The system with a condenser (SWC) maintained the reactor temperatures above 40째C for 2 days during the 8 days run, while the system without a condenser (SWOC) remained above 40째C for 6 days. The SWC maintained the reactor temperatures mostly at mesophilic conditions while the SWOC at thermophilc conditions. Differences in operation conditions for the two runs were mainly caused by differences in atmospheric temperatures. Soluble chemical oxygen demand (SCOD) and volatile solids (VS) removal efficiencies of the SWC (SCOD: 62%, VS: 41%) were higher than those of the SWOC (SCOD: 40%, VS: 20%). The total Kjeldal nitrogen (TKN) removal efficiency of the SWC (7%) was less than that of the SWOC (25%). The concentration of total volatile fatty acids (VFA) in the SWC was observed to be lower than the threshold value of 0.23 g total VFA/L after 6 days, while the SWOC progressed below the threshold value after 3 days. No offensive odor emissions were observed in either run, which suggest that the use of the ATAD system may be a good odor removal strategy.

        • KCI등재
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