• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.969-970
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• 2006

In present work, manufacturing technologies of titanium hydride powder were studied for recycling of titanium tuning chip and for this, attrition ball milling was carried out under $H_2$ pressure of 0.5 MPa. Ti chips were completely transformed into $TiH_2$ within several hundred seconds. Dehydrogenation process $TiH_2$ powders is consist of two reactions: one is reaction of $TiH_2$ to $TiH_x$ and the other decomposition of $TiH_x$ to Ti and $H_2$. The former reaction shows relatively low activation energy and it is suggested that the reaction is caused by introduction of defects due to milling.

• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.485-487
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• 2014

Nitrogen이 도핑된 graphene에서의 hydrogen evolution에 대한 촉매효과에 대해서 연구를 진행하였다. Reaction free energy를 계산하기 위해서 많은 N-doped graphene 모델을 계산하였으며 pH 조건, silicon cathode의 영향 그리고 zero point energy의 효과를 고려하였다. Volcano plot에 의하면 "pyrol" like model과 N-doped armchair graphene model (aGNR-N1)이 좋은 촉매효과를 가짐을 밝혔다. 또한 free energy diagram을 통하여 "pyrol"과 "aGNR-N1"이 좋은 active site가 될 수 있음을 확인하였고 pH가 증가함에 따라 $H^+$의 에너지가 증가함에 따라 촉매 효과가 줄어듬을 확인하였다.

• Proceedings of the SAREK Conference
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• 2004.06a
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• pp.233-233
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• 2004

• Environmental Analysis Health and Toxicology
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• v.31
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• pp.2.1-2.4
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• 2016

Objectives In this study, we investigated the biodegradation features of 4 perfluorooctanesulfonate (PFOS) alternatives developed at Changwon National University compared to those of PFOS. Methods Biodegradation testing was performed with microorganisms cultured in the good laboratory practice laboratory of the Korea Environment Corporation for 28 days following the Organization for Economic Cooperation and Development guidelines for the testing of chemicals (Test No. 301 C). Results While $C_8F_{17}SO_3Na$, PFOS sodium salt was not degraded after 28 days, the 4 alternatives were biodegraded at the rates of 20.9% for $C_{15}F_9H_{21}S_2O_8Na_2$, 8.4% for $C_{17}F_9H_{25}S_2O_8Na_2$, 22.6% for $C_{23}F_{18}H_{28}S_2O_8Na_2$, and 23.6% for $C_{25}F_{17}H_{32}O_{13}S_3Na_3$. Conclusions $C_{25}F_{17}H_{32}S_3O_{13}Na_3$, $C_{23}F_{18}H_{28}S_2O_8Na_2$, and $C_{15}F_9H_{21}S_2O_8Na_2$ were superior to PFOS in terms of biodegradation rates and surface tension, and thus they were considered highly applicable as PFOS alternatives. Environmental toxicity, human toxicity, and economic feasibility of these compounds should be investigated prior to their commercialization.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2256-2262
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• 2023

The electrochemical corrosion behaviors of SA106 Grade B (SA106B) carbon steel in H₂SO₄4-N₂H₄ and H₂SO₄-N₂H₄-CuSO₄ solutions at 95 ℃ have been investigated with the addition of commercial corrosion inhibitors (CI#30 and No. 570S), to determine the stability of SA106B in the hydrazine-based reductive metal ion decontamination (HyBRID) process. The potentiodynamic polarization experiment revealed that the corrosion inhibitors were capable of lowering the corrosion rate of SA106B in H₂SO₄-N₂H₄ solution. It was found that the corrosion inhibitors induced formation of fixed surface layer on the carbon steel upon the corrosion. This corrosion inhibition performance was reduced in the presence of CuSO₄ in the solution owing to the chemical reactions between organic compounds in the corrosion inhibitors and CuSO₄. CI#30 showed a better corrosion inhibition effect in the H₂SO₄-N₂H₄-CuSO₄ solution. Although the corrosion inhibitors can provide better stability to SA106B in the HyBRID solution, their application should be carefully considered because it may result in reduced decontamination performance and increased secondary waste generation.

• Toxicological Research
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• v.18 no.4
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• pp.363-367
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• 2002

Reactive of gen species (ROS) contribute to several cellular function and are involved in the regulation of signal transduction, gene expression, and proliferation. In the present study, we investigated the effect of $H_2O_2$ treatment on IgM secretion in LPS-stimulated murine B Iymphoma, CH12.LX. Cells were treated directly With $H_2O_2$ and stimulated with LPS. $H_2O_2$ treatment during 72 h time period inhibited IgM secretion in LPS-stimulated CH12.LX cells in a dose- and time-dependent manners. After treatment with 50 $\mu\textrm{M}$ $H_2O_2$ during 72 h time period, the level of IgM in LPS-stimulated CH12.LX cells was markedly decreased, whereas cell viability was not significantly changed. Addition of $H_2O_2$ concomitantly with LPS, or 12 h post-LPS stimulation, produced a significant inhibition of IgM secretion, Whereas inhibitory effect of $H_2O_2$ on IgM secretion was not observed when added 24 h after LPS stimulation. These findings suggest that $H_2O_2$ can inhibit the secretion of IgM in LPS-stimulated CH15.LX cells, and may alter the events necessary for terminal B cell differentiation.

• Solar Energy
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• v.12 no.3
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• pp.10-20
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• 1992

In this experiment, photochemical reaction has been applied to destroy TCE in water phase. The main target of this work is to investigate the technical feasibility of large scale of solar detoxification reactor for water treatment. The results have revealed that solar detoxification utilizing photon energy from the sun is the most attractive process to decompose organic toxins in water phase at room temperature. The detailed results from this work are as follows; (1) The highest conversion ratio of TCE was obtained by using $TiO_2$, annatase as a photocatalyst among $TiO_2$ anatase, $TiO_2$ rutile and $V_2O_5$ under the same experimental condition. The anatase crystal structure was confirmed with XRD analysis, and its surface area was 7.748 $m^2/g$ from the BET-$N_2$ measurement (2) 0.1 wt% of $TiO_2$ anatase has been adopted as optimal quantity for batch slurry reactor at this experimental conditions. (3) The effect of hydrogen peroxide on the conversion of TCE was investigated. Its optimal quantity was 0.06 vol. % under this experimental conditions. (4) The effect of oxygen on the conversion of TCE also was studied by controlling the head space in photoreactor. Results indicated that sufficient amount of oxygen should be supplied to accomplish the highest conversion rate of TCE in water phase.

• Environmental Engineering Research
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• v.24 no.3
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• pp.389-396
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• 2019

The electrical energy consumption (EEC) in removal of NO by a $UV/H_2O_2$ oxidation process was introduced and related to removal efficiency of this gas. The absorption-reaction of NO was conducted in a bubble column reactor in the presence of $SO_2$. The variation in NO removal efficiency was investigated for various process parameters including NO and $SO_2$ inlet concentrations, initial concentration of $H_2O_2$ solution and gas flow rate. EEC values were obtained in these different conditions. The removal efficiency was increased from about 22% to 54.7% when $H_2O_2$ concentration increased from 0.1 to 1.5 M, while EEC decreased by about 70%. However, further increase in $H_2O_2$ concentration, from 1.5 to 2, had no significant effect on NO absorption and EEC. An increase in NO inlet concentration, from 200 to 500 ppm, decreased its removal efficiency by about 10%. However, EEC increased from $2.9{\times}10^{-2}$ to $3.9{\times}10^{-2}kWh/m^3$. Results also revealed that the presence of $SO_2$ had negative effect on NO removal percentage and EEC values. Some experiments were conducted to investigate the effect of $H_2O_2$ solution pH. The changing of pH of oxidation-absorption medium in the ranges between 3 to 10, had positive and negative effects on removal efficiency depending on pH value.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.365-371
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• 2010

The multiconfiguration molecular mechanics (MCMM) algorithm was used to generate potential and vibrationally adiabatic energy surfaces for excited-state tautomerization in the 1:1 7-azaindole:$H_2O$ complex. Electronic structures and energies for reactant, product, transition state were computed at the CIS/6-31G(d,p) level of theory. The potential and vibrationally adiabatic energies along the reaction coordinate were generated step by step by using 16 high-level Shepard points, which were computed at the CIS/6-31G(d,p) level. This study shows that the MCMM method was applied successfully to make quite reasonable potential and adiabatic energy curves for the excited-state double proton transfer reaction. No stable intermediates are present in the potential energy curve along the reaction coordinate of the excited-state double proton transfer in the 1:1 7-azaindole:$H_2O$ complex, indicating that these two protons are transferred concertedly. The change in the bond distances along the reaction coordinate shows that two protons move very asynchronously to make an $H_3O^+$-like moiety at the transition state.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.4
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• pp.299-304
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• 2008

Thermal decomposition of Ammonia Borane have been investigated with various analytical methods including TGA, TP-MS, DSC. By-products such as aminoborane and borazine were identified during hydrogen release by TGA, TP-MS analysis. $H_2$ release amount was measured at each temperature isothermally, which resulted in 7 wt% $H_2$ release at 130$^{\circ}C$. Moreover, higher temperature enhanced hydrogen release kinetics leading to shortened induction period from 20 min at 95$^{\circ}C$ to 0 min at 130$^{\circ}C$. Melting and decomposition at close temperature (4$^{\circ}C$ difference) caused the formation of thin foam during hydrogen release. Suppression of by-products and thin foam formation during hydrogen release is suggested as critical issues to realize chemical hydrogen storage system with ammonia borane.