• 한국환경과학회지
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• 제21권5호
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• pp.555-562
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• 2012

The experimental determination of equilibrium constants is required to estimate concentrations of reagents and/or products in environmental chemical reactions. For an example, the choice of copper (Cu) complexation reactions was motivated by their fast kinetics and the ease of measurement of Cu by an ion-sensitive electrode. Each individual titrant of sulfate ($SO{_4}^{2-}$) and oxalate ($C_2O{_4}^{2-}$) was expected to have its own unique characteristics, depending on the bonding in Culigands connected to the aqueous species. The complexation reaction of Cu with $SO{_4}^{2-}$ somewhat fast reached equilibrium status compared with $C_2O{_4}^{2-}$. The experimental equilibrium constants ($K_{eq}$) of copper sulfate ($CuSO_4$) and copper oxalate ($CuC_2O_4$) were determined $10^{2.2}$ and $10^{3{\sim}4.3}$, respectively.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.147.2-147.2
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• 2003

A fast and matrix-assisted laser desorption/ionization-mass spectrometry compatible protein staining method in one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis is described. It is based on the counterion dye staining method that employs oppositely charged two dyes, Zincon and Ethyl Violet to form an ion-pair complex. It is safe to use since the methanol used previously in staining solution was replaced with ethanol, which is not toxic. The protocol including fixing, staining and quick washing steps can be completed in 1 to 1.5 h depending upon gel thickness. (omitted)

• 전자공학회논문지SC
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• 제37권4호
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• pp.49-54
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• 2000

고분자 이온 감응막을 광도파로로 이용한 새로운 형태의 센서소자를 제작하여 칼슘이온의 농도 변화에 따른 그 특성을 평가하였다. 광도파로 소자는 실리카 유리기판에 기존의 반도체 사진식각법 (photolitho-graphy)을 이용하여 도파로가 형성되어질 부분을 에칭한 후 감지막을 스핀코팅법으로 코팅하여, 그 자체를 도파로로 이용한 고속 응답의 새로운 형태의 센서소자를 제작하였다. 도파로로 사용된 감지막은 칼슘이온에 대해 특이성을 가지는 변색성 이온감응물질인 ETH5294, 중성이온감응물질인 K23El, anionic site인 NaTm(CF/sub 3/)/sub 2/PB, 가소제인 DOP 및 PVC-PVAC-PVA 폴리머를 THF 용매에 녹여 스핀 코팅법으로 제작하였다. 여러 가지 변수에 따른 센서의 특성을 평가하기 위하여 도파로의 두께(즉, 감지막의 두께), 변색성 이온감응물질의 농도, 각 모드 변화에 따른 센서의 감응특성을 비교 평가하였다. 제작된 센서는 칼슘이온에 대해 1×10­6∼1M의 측정 범위를 가지며, 1×10­⁴∼1×10­¹M 영역에서 선형성을 가지며, 기존의 광학적 측정 방법인 분광분석법에 비해 높은 감도를 나타냄을 확인하였다.

• 공업화학
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• 제30권6호
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• pp.737-741
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• 2019

본 연구에서는 스크린 프린팅 공정을 이용하여 저렴하고 유연한 칼륨 이온(K⁺) 센서를 제작하였다. 전도성 잉크의 균일한 코팅은 주사 전자 현미경 및 광학 현미경 측정에 의해 입증되었다. K⁺ 센서는 높은 감도, 빠른 응답 시간, 낮은 검출 한계를 보여주었다. 제조된 K⁺ 센서의 감도는 기계적으로 구부러진 상태에도 여전히 유지되었다. 히스테리시스 효과가 없는 우수한 반복성과 우수한 장기 안정성이 K⁺ 센서의 전기화학적 특성 분석에서 관찰되었다. 또한, K⁺ 센서는 다른 간섭 양이온이 존재하는 경우에도 정확하게 K⁺ 농도를 측정 할 수 있어 우수한 선택성을 증명하였다. 또한, 실제 스포츠 음료 샘플에서 K⁺ 농도의 성공적인 측정은 K⁺ 센서의 K⁺ 농도 값과 상용 K⁺ 미터를 비교하여 증명되었다.

• Bulletin of the Korean Chemical Society
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• 제29권4호
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• pp.790-794
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• 2008

Nucleophilic addition reaction of benzenethiols (PhSH) to 1-(2-nitrovinyl) benzenes ($\beta$ NS) in the presence of triethylamine (TEA) has been studied in acetonitrile at 25 ${^{\circ}C}$. The rate is first order with respect to [PhSH], [TEA] and [$\beta$ NS]. The reaction is found to proceed with the formation of ion-pair between benzenethiol and TEA. A suitable mechanism with the formation of an adduct between ion-pair and substrate in a slow step followed by its rearrangement to 1,2-addition product in a fast step has been proposed and corresponding rate law derived. From the rate law, the rate constants for the interaction between ion-pair and $\beta$NS have been evaluated. Interestingly, in both para-substituted substrates and benzenethiols the rate increases with the electron-withdrawing power of the substituents. The positive sign of $\rho_x$ in benzenethiols has been explained. The magnitude of cross-interaction constant, $\rho_{xy}$ is small (0.08). The magnitude of the Hammett $\rho_x$ values is higher than that of the Bronsted, $\beta_x$ values for benzenethiols. The kinetic isotope effect, $k_H/k_D$, is found to be greater than unity. A suitable transition state with simultaneous formation of $C_\beta$ -H and $B_\alpha$ -S bonds involving the ion-pair and $\beta$NS in a single concerted step has been proposed to account for these observations.

• 공업화학
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• 제19권3호
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• pp.304-309
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• 2008

1％, 2％, 4％ 및 8％의 가교도를 가진 스타이렌(제4류 위험물) 디비닐벤젠 공중합체에 1-aza-12-crown-4 거대고리 리간드를 치환반응으로 결합시켜 cryptand계 이온교환 수지들을 합성하였다. 이들 수지의 합성은 염소 함량, 원소 분석, 전자현미경 그리고 IR-스펙트럼으로 확인하였다. 우라늄(${UO_2}^{2+}$) 이온의 흡착에 미치는 pH, 시간, 수지의 가교도 그리고 용매의 유전상수에 따른 영향들을 조사한 결과 우라늄 이온은 pH 3 이상에서 큰 흡착율을 보였으며, 금속 이온들의 흡착 평형은 2 h 정도였다. 한편, 에탄올 용매에서 수지에 대한 흡착 선택성은 우라늄(${UO_2}^{2+}$) > 니켈($Ni^{2+}$) > 가돌리늄($Gd^{3+}$) 이온이었고, 우라늄 이온의 흡착력은 1％, 2％, 4％ 및 8％의 가교도 순이었으며, 용매의 유전상수 크기에 반비례하였다.

• 공업화학
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• 제34권5호
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• pp.556-565
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• 2023

Fast industrial and agricultural expansion result in the production of heavy metal ions (HMIs). These are exceedingly hazardous to both humans and the environment, and the necessity to eliminate them from aqueous systems prompts the development of novel materials. In the present study, a UIO-66 (COOH)₂ metal-organic framework (MOF) containing free carboxylic acid groups was post-synthetically modified with L-glutamic acid via the solid-solid reaction route. Pristine and glutamic acid-treated MOF materials were characterized in detail using several physicochemical techniques. Single-ion batch adsorption studies of Pb(II) and Hg(II) ions were carried out using pristine as well as amino acid-modified MOFs. We further examined parameters that influence removal efficiency, such as the initial concentration and contact time. The bare MOF had a higher ion adsorption capacity for Pb(II) (261.87 mg/g) than for Hg(II) ions (10.54 mg/g) at an initial concentration of 150 ppm. In contrast, an increased Hg(II) ion adsorption capacity was observed for the glutamic acid-modified MOF (80.6 mg/g) as compared to the bare MOF. The Hg(II) ion adsorption capacity increased by almost 87% after modification with glutamic acid. Fitting results of isotherm and kinetic data models indicated that the adsorption of Pb(II) on both pristine and glutamic acid-modified MOFs was due to surface complexation of Pb(II) ions with available -COOH groups (pyromellitic acid). Adsorption of Hg(II) on the glutamic acid-modified MOF was attributed to chelation, in which glutamic acid grafted onto the surface of the MOF formed chelates with Hg(II) ions.

• 한국인터넷방송통신학회논문지
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• 제24권2호
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• pp.133-138
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• 2024

리튬이온 배터리는 높은 에너지 밀도 빠른 충전조건 긴 사이클수명의 특성으로 여러 분야에서 사용되고 있다. 하지만 리튬이온 배터리는 과충전, 과방전, 물리적손상, 고온에서의 사용은 배터리 수명 감소와 보호회로 손상에 의한 화재 및 폭발에 의한 인명피해를 입힐 수 있다. 이러한 배터리의 위험성을 낮추며 배터리 성능을 향상시키기 위해서는 충전 및 방전 과정에서의 특성들을 분석하고 이해하여야 한다. 따라서 본 논문에서는 배터리 충방전기와 시뮬레이터를 활용하여 리튬이온 배터리의 충전 및 방전 특성을 분석하여 과충전 과방전에 따른 배터리 수명 감소와 보호회로 손상에 의한 화재 및 폭발에 의한 인명피해를 줄이고자 한다.

• 펄프종이기술
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• 제38권2호
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• pp.9-15
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• 2006

Neutral sizing is required for linerboard to solve the troubles in strength and process caused by recycled raw materials. AKD sizing efficiency can be influenced by process condition like white water quality, fines retention and so on. Therefore, this study was aimed to evaluate sizing performance of general and fast cure type AKDs using process water obtained from linerboard mill. To evaluate effect of process water quality on AKD sizing, white water was diluted with tap water at the different dilution ratios and UKP slurry was sized using the prepared water. Also, effects of inorganic and organic ion material on sizing were examined. When white water was used for stock forming, UKP sheet showed very low sizing degree. Sizing degree of sheet was increased with increase of dilution ratio because water quality was improved. Especially anionic organic material had a greater influence on AKD sizing than inorganic material. When white water quality was deteriorated, fast cure type AKD showed superior sizing performance to general type AKD.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(4)
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• pp.413-418
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• 1996

To derive the optimimum antenna launching condition for fast wave current drive, the propagation and absorption of the ion cyclotron range of frequencies waves are studied in a KT-2 tokamak plasma. We sove the kinetic wave equation in one dimensional slab geometry with the phase-shifted antenna array to inject the toroidal momentum to electrons. The accessibility conditions and the guidelines of the optimum antenna design for the efficient current drive are derived. The dependence of the current drive efficiency on launching conditions such as the phase and spacing Is presented.