• Bulletin of the Korean Chemical Society
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• 제34권9호
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• pp.2577-2582
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• 2013

A novel stick-shaped portable sensing device featuring a microhole array interface between the polyvinylchloride-2-nitrophenyloctylether (PVC-NPOE) gel and water phase was developed for in-situ sensing of perchlorate ions in real water samples. Perchlorate sensitive sensing responses were obtained based on measuring the current changes with respect to the assisted transfer reaction of perchlorate ions by a perchlorate selective ligand namely, bis(dibenzoylmethanato)Ni(II) (Ni(DBM)2) across the polarized microhole array interface. Cyclic voltammetry was used to characterize the assisted transfer reaction of perchlorate ions by the $Ni(DBM)_2$ ligand when using the portable sensing device. The current response for the transfer of perchlorate anions by $Ni(DBM)_2$ across the micro-water/gel interface linearly increased as a function of the perchlorate ion concentration. The technique of differential pulse stripping voltammetry was also utilized to improve the sensitivity of the perchlorate anion detection down to 10 ppb. This was acquired by preconcentrating perchlorate anions in the gel layer by means of holding the ion transfer potential at 0 mV (vs. Ag/AgCl) for 30 s followed by stripping the complexed perchlorate ion with the ligand. The effect of various potential interfering anions on the perchlorate sensor was also investigated and showed an excellent selectivity over $Br^-$, $NO_2{^-}$, $NO_3{^-}$, $CO{_3}^{2^-}$, $CH_3COO^-$ and $SO{_4}^{2^-}$ ions. As a final demonstration, some regional water samples from the Sincheon river in Daegu city were analyzed and the data was verified with that of ion chromatography (IC) analysis from one of the Korean-certified water quality evaluation centers.

• Korean Journal of Acupuncture
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• 제27권4호
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• pp.49-57
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• 2010

Objectives : The aim of this study is evaluation for significance of skin meridian-acupoints energy measurement system, and is verification of principle to measure the bio-ion charge on acupoints. Methods : To check a correlation between the MEP(Meridian Energy Potential) and bio-electric charge condition, ten acupoints(left/right BL meridian : BL13, BL15, BL18, BL20, BL23) were chosen. Based on basic theory concerning the upward trend of the bio-electric charge by cupping therapy, we measured MEP change before and after 600mmHg(80kPa) Negative pressure stimulation using cupping. Results : We could identify the correlation between MEP and the condition of bio-electric charge in acupoints. Also, we checked the balance or imbalance of left/right the MEP and unusual cases. Conclusions : We confirmed significance of proposed principle and meridian energy measurement system.

• KSBB Journal
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• 제18권2호
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• pp.122-126
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• 2003

본 연구에서는 다중 이온교환크로마토그래피로 리소짐을 분리하는 공정개발을 위해 Cellufine CM C-200과 Bio-rex 70 겔을 이용하여 비교 실험하였다. 난백에서 Iysozyme의 분리, 정제 및 수지의 활용성을 확인하는 실험이었다. 실험결과 Cellufine겔은 5 주기가 지나면서부터 용출분획에서 낮은 농도의 단백질이 용출됨을 확인하였다. 이는 주기가 진행될 수록 겔의 흡착능력이 약화됨을 보여주는 것이다. 또한 주기가 진행될수록 각 주기의 크로마토그램을 분석한 결과, 단백질이 겔의 작용기와 효과적으로 흡·탈착 작용을 하고 있지 못하기 때문에 용출영역의 peak가 계속해서 낮아지는 경향을 보였다. 그러나 Bio-rex 70겔은 6 주기를 수행 후에도 겔의 흡착능력이 상실되지 않고 단백질과 효과적으로 결합함을 용출영역의 크로마토그램과 전기영동에서 확인하였다. Bio-rex 겔은 Cellufine겔보다 단백질과 작용기와의 결합력이 우수하였으나 순수한 Iysozyme의 정제에 있어서 적당하지 못함을 알 수 있었다. Iysozyme의 용출 이온강도가 다른 단백질들보다 더 강하기 때문에 용출용액의 소금 농도구배를 실행함으로써 단백질을 용출한다면 순수한 IysoByme을 정제할 수 있다고 생각된다. 따라서 본 실험결과 다중 이온교환크로마토그래피 공정에 효과적인 겔은 Bio-rex 70겔임을 알 수 있었다.

• 공업화학
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• 제24권3호
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• pp.291-298
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• 2013

공액 리놀레산 메틸에스테르는 불균일계 촉매인 니켈 담지 제올라이트계 촉매를 이용하여 리놀레산 메틸에스테르의 이성질화를 통해 합성할 수 있다. 니켈 담지 제올라이트계 촉매는 HY 제올라이트로부터 KCl 수용액을 이용해 이온교환하여 KY 제올라이트를 합성한 뒤 함침법을 통해 니켈을 담지하여 합성하였다. 합성된 촉매는 수소를 이용하여 전처리하여 공액화 반응에 사용하였다. 그 결과 낮은 온도에서 HY 촉매는 높은 전환율을 나타내었지만 공액화 반응에 대해 낮은 선택도를 나타내었다. KY 촉매는 낮은 온도에서 상대적으로 낮은 전환율을 나타내었으나 높은 온도에서 HY 촉매와 유사한 전환율을 보였으며, 낮은 온도에서도 공액화 반응에 대해 높은 선택도를 나타내었다. 결과적으로 반응 온도 $220^{\circ}C$에서 4 wt% Ni/KY720을 이용하여 가장 높은 63.4%의 수율을 얻었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.55.2-55.2
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• 2012

Intensive theoretical and experimental studies have been carried out at Korean Institute of Science and Technology (KIST) on controlling the bio absorbing rate of the Mg alloys with high mechanical strength through tailoring of electrochemical potential. Key technology for retarding the corrosion of the Mg alloys is to equalize the corrosion potentials of the constituent phases in the alloys, which prevented the formation of Galvanic circuit between the constituent phases resulting in remarkable reduction of corrosion rate. By thermodynamic consideration, the possible phases of a given alloy system were identified and their work functions, which are related to their corrosion potentials, were calculated by the first principle calculation. The designed alloys, of which the constituent phases have similar work function, were fabricated by clean melting and extrusion system. The newly developed Mg alloys named as KISTUI-MG showed much lower corrosion rate as well as higher strength than previously developed Mg alloys. Biocompatibility and feasibility of the Mg alloys as orthopedic implant materials were evaluated by in vitro cell viability test, in vitro degradation test of mechanical strength during bio-corrosion, in vivo implantation and continuous observation of the implant during in vivo absorbing procedures. Moreover, the cells attached on the Mg alloys was observed using cryo-FIB (focused ion beam) system without the distortion of cell morphology and its organ through the removal of drying steps essential for the preparation of normal SEM/TEM samples. Our Mg alloys showed excellent biocompatibility satisfying the regulations required for biomedical application without evident hydrogen evolution when it implanted into the muscle, inter spine disk, as well as condyle bone of rat and well contact interface with bone tissue when it was implanted into rat condyle.

• 한국건설순환자원학회논문집
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• 제7권4호
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• pp.445-451
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• 2019

본 연구에서는 콘크리트 교면포장 재료로서 사용되는 라텍스의 단점인 경제성을 보완하고 자원재활용을 위해 괭생이모자반 기반의 자원순환형 폴리머 혼입에 따른 내구성능을 분석하였다. 본 연구 범위의 모든 배합조건에서 슬럼프 및 공기량은 품질기준은 만족하는 것으로 나타났으나, 분말 형태의 자원순환형 바이오 폴리머 적용시 슬럼프가 일부 저하되는 경향을 나타내었다. 압축강도 시험결과, 라텍스 혼입시 강도가 감소되었지만 바이오 폴리머 대체시 혼입율에 따라 6.3~24.4%의 강도 개선효과를 나타내었다. 내구성능 시험결과, 합성 폴리머 혼입시 가장 우수한 내구성능을 나타내었고, 바이오 폴리머 혼입시에는 혼입율이 증가할수록 내구성능이 우수한 경향을 나타내었지만 라텍스보다는 미소하게 낮은 것으로 확인되었다.

• Tribology and Lubricants
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• 제30권6호
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• pp.323-329
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• 2014

The friction-reducing properties of lubricants containing ionic liquids based on ammonium dithiocarbamate are studied. The ionic liquids are produced through the following two steps: the synthesis of sodium alkyl dithiocarbamates via the substitution reaction of dialkylamine and carbon disulfide and their subsequent conversion into ammonium dithiocarbamate-based ionic liquids through an ion-exchange reaction with a quaternary alkyl ammonium halide salt. The structures of the ionic liquids are characterized by NMR spectroscopy and Fourier transform infrared spectroscopy. The isolated yields of the ionic liquids, which are viscous and pale yellow, are approximately 92%. The Brookfield viscosities and pour points of the ionic liquids are determined. Further, their wear resistances are measured through the four-ball wear test and the Schwingung Reibung Ver-schleiss (oscillation, friction, wear) test. The wear scar diameter of the lubricants containing 1 wt of the quaternary alkyl ammonium dithiocarbamate-based ionic liquids (0.475-0.631 mm) is significantly lower than that of the base oil (0.825 mm), proving that the ammonium dithiocarbamate-based ionic liquids have good friction-reducing characteristics. However, these friction-reducing characteristics fade significantly after long-term storage, owing to the degradation of the ionic liquids.

• Molecules and Cells
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• 제23권3호
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• pp.363-369
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• 2007

Mitochondria play a central role in energy-generating processes and may be involved in the regulation of channels and receptors. Here we investigated TRPM7, an ion channel and functional kinase, and its regulation by mitochondria. Proton ionophores such as CCCP elicited a rapid decrease in outward TRPM7 whole-cell currents but a slight increase in inward currents with pipette solutions containing no MgATP. With pipette solutions containing 3 mM MgATP, however, CCCP increased both outward and inward TRPM7 currents. This effect was reproducible and fully reversible, and repeated application of CCCP yielded similar decreases in current amplitude. Oligomycin, an inhibitor of $F_1/F_O$-ATP synthase, inhibited outward whole-cell currents but did not affect inward currents. The respiratory chain complex I inhibitor, rotenone, and complex III inhibitor, antimycin A, were without effect as were kaempferol, an activator of the mitochondrial $Ca^{2+}$ uniporter, and ruthenium red, an inhibitor of the mitochondrial $Ca^{2+}$ uniporter. These results suggest that the inner membrane potential (as regulated by proton ionophores) and the $F_1/F_O$-ATP synthase of mitochondria are important in regulating TRPM7 channels.

• 농업과학연구
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• 제50권4호
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• pp.967-976
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• 2023

Biochar is emerging as a promising substance for achieving carbon neutrality and climate change mitigation. It can absorb several nutrients via ion bonding on its surface functional groups, resulting in slow dissociation of the bonds. Biochar, like organic fertilizers, contributes to sustainable nutrient management. The purpose of this study was to investigate the effects of nutrient-coated biochar amendments on leafy vegetables production and soil fertility. The nutrient-coated biochar was produced by soaking rice husk biochar in a nutrient solution containing nitrogen (N), phosphorus, and potassium for 24 hours. Nutrient-coated biochar and organic fertilizers were applied to soil at a rate of 120 kg·N·ha^-1. The growth components of the leafy vegetables showed that nutrient-coated biochar led to the highest fresh weight (FW) of both lettuce and kale (i.e., 146.67 and 93.54 g·plant^-1 FW, respectively). As a result, nutrient-coated biochar amendments led to superior yield compared to the control treatment and organic fertilization. The elemental composition of leafy vegetables revealed that soil amended with nutrient-coated biochar resulted in higher nutrient contents, which was attributed to the high nutrient contents supplied by the rice husk biochar. Soil amendment with nutrient-coated biochar positively enhanced the soil fertility compared to amendment with organic fertilizer. Therefore, nutrient-coated biochar is a promising substance for enhancing agronomic performance of leafy vegetables and improving soil fertility.

• 한국전기전자재료학회논문지
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• 제25권9호
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• pp.711-716
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• 2012

Based on both organic synthesis and theoretical calculations on the effects of molecular orbital energy levels of amines on the fluorescence properties of the fluorophore, fluorescent "turn-on" chemosensors detecting hazardous substances, including aldehyde chemicals and $Hg^{2+}$ ion, were developed.