• Journal of Electrochemical Science and Technology
• /
• 제4권4호
• /
• pp.146-152
• /
• 2013

We demonstrate that carbon electrodes screen-printed directly on cellulose paper can be employed to perform bipolar electrochemistry. In addition, an array of 18 screen-printed bipolar electrodes (BPEs) can be simultaneously controlled using a single pair of driving electrodes. The electrochemical state of the BPEs is read-out using electrogenerated chemiluminescence. These results are important because they demonstrate the feasibility of coupling bipolar electrochemistry to microfluidic paperbased analytical devices (${\mu}PADs$) to perform highly multiplexed, low-cost measurements.

• 한국응용과학기술학회지
• /
• 제27권4호
• /
• pp.531-538
• /
• 2010

The electrochemistry characterization of metal is important in many industrial applications. In this study, we investigated the C-V diagrams related to the electrochemistry characterization of nickel. We determined electrochemical measurement by using cyclic voltammetry with a three electrode system. A measuring range was reduced from initial potential to -1350mV, continuously oxidized to 1650mV and measured to the initial point. The scan rate were 100, 150, 200 and 200mV/s. As a result, the C-V characterization of nickel using ethanolamine and ethylethanolamine inhibitor appeared irreversible process caused by the oxidation current from the cyclic voltammogram. After adding ethanolamine compound additive, adsorption film constituted, and the passive phenomena happened. According to the results by cyclic voltammetry method, it was revealed that the effect of the electrochemistry characterization of nickel depends on ethanolamine structure interaction to adsorption complex.

• Nuclear Engineering and Technology
• /
• 제54권9호
• /
• pp.3580-3585
• /
• 2022

The thermal stability of carbohydrazide, hydrazine nitrate, acetohydroxamic acid in nitric acid solutions has been studied at atmospheric pressure and above atmospheric pressure. The volumes of gaseous products of thermolysis and the maximum rate of gas evolution have been determined at atmospheric pressure. It has been shown that, despite the high rate of gas evolution and large volumes of evolved gases, the conditions for the development of autocatalytic oxidation are not created. Exothermic processes are observed in a closed vessel in the temperature range of 50-250 ℃. With an increase in the concentration of nitric acid, the temperatures of the onset of exothermic effects for all mixtures decrease, and the values of the total thermal effects of reactions increase, to the greatest extent for solutions with carbohydrazide.

• Bulletin of the Korean Chemical Society
• /
• 제18권1호
• /
• pp.6-8
• /
• 1997

• 대한화학회지
• /
• 제61권1호
• /
• pp.34-44
• /
• 2017

이 연구에서는 대학 신입생을 대상으로 고등학교에서 화학II 선택과목 이수가 대학 일반화학에서 전기화학 관련 개념을 이해하는데 미치는 영향과 개념 변화 유형을 알아보았다. 고등학교에서 화학II 이수 여부에 따라 전기화학 관련 개념의 이해에 유의미한 차이가 있었다. 화학전지의 구별, 전극의 구별, 그리고 전류의 생성과 흐름에 관한 개념의 이해에서 차이가 크게 나타났으나 염다리의 역할, 표준 반쪽 전지의 필요성에서는 유의미한 차이가 나타나지 않았다. 화학전지의 생성물과 전지 전위의 예측에서는 화학II를 이수하지 않은 학생 그룹에서 일반화학 수강 후에 개념 이해의 향상이 크게 나타났다. 고등학교에서 전기화학의 기본 개념의 학습이 대학 일반화학에서 전기화학 관련 개념의 이해에 영향을 미치고 있었으나 일반화학을 수강하더라도 몇 가지 관련 개념의 정확한 이해에는 많은 어려움을 가지고 있음을 알 수 있었다. 이의 해결을 위해서는 전기화학의 기본 개념에 대하여 보다 정확한 내용의 교육이 이루어질 필요가 있고, 고등학교에서 미리 학습하지 못한 학생들을 위한 적절한 보충 학습을 해야 할 필요성이 있다.

• Nuclear Engineering and Technology
• /
• 제52권1호
• /
• pp.123-134
• /
• 2020

The interaction between UN and CdCl₂ in the LiCl-KCl molten eutectic was studied at 773 K. The reaction was controlled by sampling the melt, as well as by analysis of the resulting precipitate. The process was shown to proceed according to several parallel reactions. The summary reaction was determined to have two stages: a fast one and a slow one. The 19-53% UN → UCl₃ conversion was obtained for the molar ratio of CdCl₂/UN = 1.22-14.9. The rest of UN converts into the precipitate of complex composition (UNCl + U₂N₃ + U₄N₇ + UN₂). The increase in the CdCl₂/UN molar ratio from 1.22 to 14.9 resulted in the decrease in duration of the first "fast" stage of the process from 18 h to 1 h.

• 한국전기화학회:학술대회논문집
• /
• 한국전기화학회 2000년도 춘계총회 및 학술발표회
• /
• pp.43-43
• /
• 2000

• 한국표면공학회지
• /
• 제54권1호
• /
• pp.1-11
• /
• 2021

Porous dendrite structure AuCu alloy was formed using a hydrogen bubble template (HBT) technique by electroplating to improve the catalytic performance of gold, known as an excellent oxygen reduction reaction (ORR) catalyst in alkaline medium. The rich Au surface was maximized by selectively electrochemical etching Cu on the AuCu dendrite surface well formed in a leaf shape. The catalytic activity is mainly due to the synergistic effect of Au and Cu existing on the surface and inside of the particle. Au helps desorption of OH- and Cu contributes to the activation of O2 molecule. Therefore, the porous AuCu dendrite alloy catalyst showed markedly improved catalytic activity compared to the monometallic system. The porous structure AuCu formed by the hydrogen bubble template was able to control the size of the pores according to the formation time and applied current. In addition, the Au-rich surface area increased by selectively removing Cu through electrochemical etching was measured using an electrochemical calculation method (ECSA). The results of this study suggest that the alloying of porous AuCu dendrites and selective Cu dissolution treatment induces an internal alloying effect and a large specific surface area to improve catalyst performance.

• 한국수소및신에너지학회논문집
• /
• 제2권1호
• /
• pp.47-56
• /
• 1990

Pure titanium rods were oxidized by anodic oxidation, furnace oxidation and flame oxidation and used as a electrode in the photodecomposition of water. The maximum photoelectrochemical conversion efficiency(${\eta}$) was found for flame oxidized electrode ($1200^{\circ}C$ for 2 min in air), 0.8 %. Anodically oxidized electrodes have minimum photoelectrochemical conversion efficiencies, 0.3 %. Furnace oxidized electrode ($800^{\circ}C$ for 10min in air) has 0.5% phtoelectrochemical efficiency and shows a band-gap energy of about 2.9eV. The efficiency shows a parallelism with the presence of the metallic interstitial compound $TiO_{O+X}$(X < 0.33) at the metal-semiconductor interface, the thickness of the sub oxide layer and that of the external rutile scale.

• 전기화학회지
• /
• 제4권1호
• /
• pp.21-25
• /
• 2001

프랙탈 기하학의 계면 전기화학에로의 응용과 관련하여 프랙탈 표면을 향한 이온/원자 확산의 속도론에 대하여 다루었다. 우선 프랙탈 기하학의 기본 개념에 대하여 설명하였고, 이를 바탕으로 이온/원자의 확산 현상과 관련하여 다양한 전기적 입력하에서 전극 표면의 프랙탈 특성에 기인하는 특수한 반응 양상이 설명되었다 Chronoamperometry, chronopotentiometry및 linear sweep/cyclic voltammetry 실험시에 각각 관찰되는, 전극의 프랙탈 차원이 포함된 일 반화된 Cottrell, Sand 및 Randles-Sevcik 관계를 이론적으로 유도하였고, 그 의미에 대하여 설명하였다