• Transactions of the Korean hydrogen and new energy society
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• v.22 no.1
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• pp.51-59
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• 2011

Sulfur-Iodine (SI) cycle, which thermochemically splits water to hydrogen and oxygen through three stages of Bunsen reaction, HI decomposition, and $H_2SO_4$ decomposition, seems a promising process to produce hydrogen massively. Among them, the decomposition of $H_2SO_4$ ($H_2SO_4=H_2O+SO_2+1/2O_2$) requires high temperature heat over $800^{\circ}C$ such as the heat from concentrated solar energy or a very high temperature gas-cooled nuclear reactor. Because of harsh reaction conditions of high temperature and pressure with extremely corrosive reactants and products, there have been scarce and limited number of data reported on the pressurized $H_2SO_4$ decomposition. This work focuses whether the $H_2SO_4$ decomposition can occur at high pressure in a noble-metal reactor, which possibly resists corrosive acidic chemicals and possesses catalytic activity for the reaction. Decomposition reactions were conducted in a Pt-lined tubular reactor without any other catalytic species at conditions of $800^{\circ}C$ to $900^{\circ}C$ and 0 bar (ambient pressure) to 10 bar with 95 wt% $H_2SO_4$. The Pt-lined reactor was found to endure the corrosive pressurized condition, and its inner surface successfully carried out a catalytic role in decomposing $H_2SO_4$ to $SO_2$ and $O_2$. This preliminary result has proposed the availability of noble metal-lined reactors for the high temperature, high pressure sulfuric acid decomposition.

• Bulletin of the Korean Chemical Society
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• v.18 no.1
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• pp.61-65
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• 1997

The electrochemical properties of LixCoyNi1-yO2 compounds (y=0.1, 0.3, 0.5, 0.7, 1.0) prepared by citrate sol-gel method have been investigated. The LixCoyNi1-yO2 compounds were annealed at 850 ℃ for 20 h after preheating at 650 ℃ for 6 h, in air. The x-ray diffraction (XRD) patterns for LixCoyNi1-yO2 have shown that these compounds have a well developed layered structure (R&bar{3} m). From the scanning electron microscopy of LixCoyNi1-yO2, particle size was estimated less than 5 μm. The Li//LixCoyNi1-yO2 electrochemical cell consists of Li metal anode and 1 M LiClO4-propylene carbonate (PC) solution as the electrolyte. The differences in intercalation rate of the LixCoyNi1-yO2 in the first charge/discharge cycle were less than 0.05 e-. The first discharge capacities of LixCoO2 and LixCo0.3Ni0.7O2 were ∼130 mAh/g and ∼160 mAh/g, respectively.

• Transactions of the Korean hydrogen and new energy society
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• v.14 no.4
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• pp.321-326
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• 2003

We tried to improve the $H_2$-sorption properties of Mg by mechanical grinding under $H_2$ (reactive grinding) with CoO. The sample Mg+10wt.%CoO as prepared absorbs 1.25wt.% hydrogen and the activated sample absorbs 2.39wt.% hydrogen for 60min at 598K, $11.2barH_2$. The reactive grinding of Mg with CoO increases the $H_2$-sorption rates by facilitating nueleation(by creating defects on the surface of the Mg particles and by the additive), by making cracks on the surface of Mg particles and reducing the particle size of Mg and thus by shortening the diffusion distances of hydrogen atoms. Hydriding-dehydriding cycling increases the $H_2$-sorption rates by making cracks on the surface of Mg particles and reducing the particle size of Mg.

• The Journal of Dong Guk Oriental Medicine
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• v.7 no.1
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• pp.1-32
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• 1998

I found following idea, as a result of researching his Science idea, mainly, by translation of the "$Zh\bar{a}ng$ xi $ch\acute{u}n$ $Xu\acute{e}$ $Sh\acute{u}$ ssu $hsi\acute{a}ng$ "(張錫純 學術硏究). $Zh\bar{a}ng$ xi $ch\acute{u}n$ regarded $ch\tilde{u}ng$ $ch\bar{u}ng$ $ts'\bar{a}n$ $hs\bar{l}$' (衷中參西) as the core idea of The Chinese-Western medical combination. He didn't segregate philosophy of the West from One of the Orient. He persued to harmonize each other and thought that the Western medicint theory is included in the Chinese one in many parts. besides, He recognized that it is bad to reject each other, for the medical science's purpose is to save a life, and united The Chinese-Western medicine theory, by $ch\acute{u}ng$ $ch\tilde{u}ng$ $ch\bar{u}ng$ $ts'\bar{a}n$ $hs\bar{l}$'(衷中參西) idea which refers to consult the Western medicine on the basis of the Chinese one. Medical basic theory of $Zh\bar{a}ng$ xi $ch\acute{u}n$ brought up new views of the theory : Dae-gi(大氣), gi-Hwa(氣化) theory, Nongangubgan byung juing chi(論肝及肝病證治), Eum her chijung ja bi(陰虛治重滋脾). Lim Sangeung yong(臨床應用) of Hyul Her gub(血虛及)-Hwal Hyul Hwa $\breve{u}$ bub(活血化瘀法), on the basis of classics, such as, "$N\breve{e}i$ Ching"(內經), "Chin Kue $\breve{i}$ $y\bar{a}o$ $l\ddot{u}{\bar{e}}h$, "Shen $n\acute{u}ng$ $p\breve{e}n$ $t\acute{s}{\check{a}}o$ ching"(新農本草經) etc. I'll sum up $Zh\bar{a}ng$ xi $ch\acute{u}n's$ clinical idea now He unified Sang Han(像寒)-On Byung(溫病) with Yuk Kyung Byung Jung(六經辨證) and It was noticiable to utilize a kinds of Baek Ho Tang(白虎湯). He gave a detailed description about a method of grasp the symptoms of the cause of the internal medicine diseases and pathology and, he left abundant views of theory about using remedy and experience of clinic.

• Korean Journal of Materials Research
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• v.18 no.1
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• pp.18-21
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• 2008

The wetting behavior of molten Fe on ${\alpha}-Al_2O_3$ single crystals with three different crystallographic orientations, $R(01\bar{1}2),\;A(11\bar{2}0),\;and\;C(0001)$, was investigated using the sessile drop method under a 10%$H_2-Ar$ atmosphere at 1873 K. It was found that the differences in the contact angle of the three differently oriented ${\alpha}-Al_2O_3$ single crystals were not significant (within $5^{\circ}$, which corresponded to the changes in the work of adhesion of $157mJ/m^2$) due to the surface reconstruction.

• Korean Journal of Metals and Materials
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• v.50 no.12
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• pp.949-953
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• 2012

$MgH_2$ was employed as a starting material instead of Mg in this work. A sample with a composition of 94 wt% $MgH_2-6$ wt% Ni (called $MgH_2-6Ni$) was prepared by reactive mechanical grinding. The hydriding and dehydriding properties were then examined. An $MgH_2-Ni$ hydrogen storage alloy that does not require an activation process was developed. The alloy was prepared in a planetary ball mill by grinding for 4 h at a ball disc revolution speed of 250 rpm under a hydrogen pressure of about 12 bar. The sample absorbed 3.74 wt% H for 5 min, 4.07 wt% H for 10 min, and 4.41 wt% H for 60 min at 573 K under 12 bar $H_2$, and desorbed 0.93 wt% H for 10 min, 1.99 wt% H for 30 min, and 3.16 wt% H for 60 min at 573 K under 1.0 bar $H_2$. $MgH_2-6Ni$ after reactive mechanical grinding contained ${\beta}-MgH_2$ (a room temperature form of $MgH_2$), Ni, ${\gamma}-MgH_2$ (a high pressure form of $MgH_2$), and a very small amount of MgO. Reactive mechanical grinding of Mg with Ni is considered to facilitate nucleation, and to reduce the particle size of Mg. $Mg_2Ni$ formed during reactive mechanical grinding also increases the hydriding and dehydriding rates of the sample.

• Membrane Journal
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• v.32 no.6
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• pp.456-464
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• 2022

Hydrogen permeation performance was analyzed by manufacturing Pd and Pd-Cu membranes through electroless plating. As a support for the Pd and Pd-Cu membranes, α-Al₂O₃ ceramic hollow fiber were used. Pd-Cu membrane was manufactured through sequential electroless plating, and then annealing was performed at 500°C, for 18 h in a hydrogen atmosphere to make Pd and Cu alloy. After annealing, the Pd-Cu membrane confirmed that the alloy was formed through EDS (Energy Dispersive X-ray Spectroscopy) and XRD (X-ray Diffraction) analysis. In addition, the thickness of the Pd and Pd-Cu plating layers were measured to be about 3.21 and 3.72 µm, respectively, through SEM (Scanning Electron Microscope) analysis. Hydrogen permeation performance was tested for hydrogen permeation in the range of 350~450°C and 1~4 bar in hydrogen single gas and mixed gas (H₂, N₂). In a single hydrogen gas, Pd and Pd-Cu membranes have flux of up to 54.42 and 67.17 ml/cm²⋅ min at 450 °C and 4 bar. In the mixed gas, it was confirmed that the separation factors of 1308 and 453 were obtained under the conditions of 450 °C and 4 bar.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.2
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• pp.129-136
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• 2017

Characteristics of $ZrO_2$ felt supported Cu/Zn catalysts have been investigated for the production of hydrogen via methanol steam reforming. Cu and Zn in different weight percent were loaded using wet impregnation over $ZrO_2$ felt support. The catalysts were characterized with BET and FE-SEM. The performance of these synthesized catalysts were investigated at SCR=1.5, $GHSV=2000h^{-1}$, temperature=$300{\sim}400^{\circ}C$, and pressure=2.5~19.5 barA. The results showed that the $Cu^{32.5}Zn^{7.5}ZrO_2$ catalyst was most active in terms of methanol conversion and hydrogen production. The methanol conversion in steam reforming of methanol was 84.6% at 19.5 barA and furnace $400^{\circ}C$ over $Cu^{32.5}Zn^{7.5}ZrO_2$ catalyst. The catalysts prepared using $ZrO_2$ felt show higher reactor temperature than the pellet type catalyst at same furnace temperature.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.89-94
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• 2007

High duality BiSrCaCuO thin films fabricated by using the i-beam sputtering method at various substrate temperatures, $T_{sub}$ and oxidation gas pressures, $pO_3$. The correlation diagrams of the BiSrCaCuO phases with Tsub and $pO_3$ are established in the 2212 and 2223 compositional films. In spite of 2212 compositional sputtering, Bi2201 and Bi2223 as well as Bi2212 phases come out as stable phases depending on $T_{sub}$ and $pO_3$. From these results, the thermodynamic evaluation of ${\Delta}H$ and${\Delta}S$, which are related with Gibbs' free energy change for single Bi2212 or Bi2223 phase, was performed.

• Economic and Environmental Geology
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• v.28 no.6
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• pp.635-646
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• 1995

Mineralized zone in the Dongyang talc deposits occurs on the lowest dolomite member of the Hyangsanri Dolomite belonging to the Ogcheon Supergroup. Ore bodies are emplaced as pipe-like body along the axis of minor folds plunging $40^{\circ}$ to the west developed in these dolomite layers. Amphibolite and chlorite schist are found along the upper or lower contact of all ore bodies (Kim et al., 1963; Park and Kim, 1966). Following the recrystallization and silicification of dolomite, tremolite and tabular and leafy talc(I) of the earlier stage formed, and microcrystalline talc(II) formed in the later stage. Talc(l) and tremolite formed by the reaction between dolomite and the fluid. Whereas talc (II) formed by the reaction between dolomite and fluid, or by the reaction between early formed tremolite and fluid. During the early stage of mineralization, the fluid was the $H_2O-CO_2$ system dominant in $CO_2$, In the later stage, the composition of the fluid changed to $H_2O-NaCl-CO_2$system, and finally to the $H_2O-NaCl$ system. The pressure and temperature conditions of the formation of tremolite associated with talc(I) were 1,640~2,530 bar, and $440{\sim}480^{\circ}C$, respectively. The pressure and temperature condition of talc(II) ore formation was 1,400~2,200 bar, and $360{\sim}390^{\circ}C$, respectively. These conditions are much lower than the metamorphic pressure and temperature of the rocks from the Munjuri Formation located about 5 km to the noJ:th of Dongyang talc deposit ${\delta}^{13}C$ and ${\delta}^{18}O$ values of dolomite which is the host rock of the talc ore deposit are 2.9~5.7‰ (PDB), and -7.4~l6.8‰ (PDB), respectively. These values are little higher than those from the Cambro-Ordovician limestones of the Taebaeksan region, but belong to the range of the unaltered sedimentary dolomite. ${\delta}^{18}O$and ${\delta}D$ values of the talc from Dongyang deposit are 8.6~15.8‰ (vs SMOW), and -65~-90‰ (vs SMOW), respectively, belonging to the range of magmatic origin. These values are quite different from those measured in the metamorphic rocks of Munjuri and Kyemyungsan Formation. ${\delta}^{34}S$ value of anhydrite is 22.4‰ (CDT), which is much lower than ${\delta}^{34}S$ (30‰ vs COT) of sulfate of early Paleozoic period, and indicates the possibility of the addition of magmatic sulfur to the system. Talc ores show the textures of weak foliation and well developed crenulation cleavages. Talc ore deposit in the area is concluded as hydrothermal replacement deposit formed before the latest phase of the deformations that Ogcheon Belt has undergone.