• Economic and Environmental Geology
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• v.41 no.1
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• pp.47-56
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• 2008

pH and Eh were measured at 25 points in the abandoned Dalcheon mine. And, major ion components $(Na^+,\;K^+,\;Ca^{2+},\;Mg^{2+},\;Cl^-,\;SO_4^{2-},\;CO_3^{2-},\;HCO_3^-)$ were analyzed through groundwater sampling at 41 points. pH and Eh were measured the highest concentration in serpentinite area. And, pH was between weak alkaline and intermediate values in study area. Groundwater in study area was dominated oxidation-reduction environment caused by reaction with carbonate rock. Because sulfur components contained in carbonate, serpentinite, arsenopyrite and pyrite was dissolved by groundwater, $SO_4^{2-}$ component was high in study area. And $Ca^{2+},\;Mg^{2+}$ of cations were high. Correlation coefficients of ion components in tailing dumps were 0.95 between $Ca^{2+}\;and\;SO_4^{2-}$, 0.86 between $Ca^{2+}\;and\;Mg^{2+}$, 0.85 between $Mg^{2+}\;and\;SO_4^{2-}$. Correlation coefficients of ion components in bedrock were 0.86 between $Mg^{2+}\;and\;SO_4^{2-}$, 0.68 between $Ca^{2+}\;and\;SO_4^{2-}$. Concentration range of $Ca^{2+}$ in tailing dumps was $6.85{\sim}323.58mg/L,\;and\;3.18{\sim}207.20mg/L$ in bedrock. Concentration range of $SO_4^{2-}$ in tailing dumps was $21.54{\sim}1673.17mg/L,\;and\;2.04{\sim}1024.64mg/L$ in bedrock. By the result of Piper diagram analysis with aquifer material, groundwater in tailing dumps was $Ca-SO_4$ type. Groundwater quality types with bedrock material were Mg-$SO_4$ and Mg-$HCO_3$ types in serpentinite area, Ca-$HCO_3$ type in carbonate area, Na-K and $CO_3+HCO_3$ types in hornfels, respectively. As a result of this study, groundwater in tailing dumps were dissolved $Ca^{2+},\;Mg^{2+}\;and\;SO_4^{2-}$ components with high concentration. Also, these ion components were transported into bedrock aquifer.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.8
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• pp.1248-1256
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• 2014

The purpose of this study was to investigate the mechanisms of behind $SO_2$ formation and elevated cause of reducing power in purple bamboo salt (PBS) along with an analysis of physicochemical properties, content of sulfur compounds, oxidation reduction potential (ORP), mineral contents of salt type (MSS, mudflat solar salt; BS, bamboo salt), and addition of raw bamboo (RB). $SO_2$ content of 630 ppm was detected in PBS. $SO_2$ was not detected in MSS, BS, or RB, whereas $SO_2$ (782 ppm) from $K_2SO_4$ was detected after heating a NaCl, KCl, $MgCl_2$, $MgSO_4$, MgO, $CaCl_2$, $K_2SO_4$, and $FeSO_4$ with RB. $SO_2$ content of BS increased with baking time, and it originated from BSRB1 (13.88 ppm) to BSRB4 (109.13 ppm). $SO_3{^{2-}}$ originated only from MSSRB4 and BSRB2~BSRB4. Sulfate ion content decreased along with increasing $SO_2$ and sulfite ion contents. ORP increased with baking time of MSS and BS, and it was present at higher levels in BSRB4 (-211.40 mV) of BS than MSS. Insoluble content was higher in BS than MSS. Further, Ca, K, and Mg ion contents decreased in MSS and increased in BS with baking time. BSRB4 had 1.4 fold higher levels of Ca, 1.5 fold higher levels of Mg, and 1.8 fold higher levels of K than BS. Li, Al, Mn, Fe, and Sr in MSS as well as Al, Fe, and Ni in BS increased with baking time. Anions (Cl, $NO_3$, and Br) and heavy metals (Pb, Cd, Hg, and As) between MSS and BS were not significantly different. These results suggest that the reducing power of BS was due to $SO_2$ and sulfite ion. To increase the amounts of these compounds and reducing power, higher melting temperature and longer baking time are necessary along with BS, which is created by the addition of RB to roasted salt.

• Journal of the Korean Society of Tobacco Science
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• v.10 no.1
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• pp.3-9
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• 1988

Effect of several nitrogen fertilizer sources on the chlorine absorption by the burley tobacco plants was investigated under the field and pot condition. The nitrogen sources included compound fertilize.(containing 3.9% NH4-N and 6.1% NH2-N), (NH4)2SO4, NaNO3. (NH2)2CO and NH4NO3. The chlorine content of leaf during growing stage was high in (NH4)2SO4 plot , and the differences among nitrogen sources was remarkable at maximum growing stage. The chlorine content of cured leaf was high in (NH4)2SO4 plot. When the (NH4)2SO4 was applied, the total alkaloid content of cured leaf was increased and the color of cured leaf became undesirable with the increment of leaf chlorine. The yield, quality and value of cured leaf were high in NaNO3 plot , while low in (NH4)2SO4 plot.

• Journal of the Korean Ceramic Society
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• v.23 no.3
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• pp.27-34
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• 1986

The hydration of flyash-$Ca(OH)_2-CaSO_4$.$2H_2O$ system was stuedied with varing mixing ratio of flyahs $Ca(OH)_2$ and caSO4.2H2O The samples were steam-cured for 1-7 days at 9$0^{\circ}C$. The optimum mixing composition was flyash : Ca (OH)2=65:35 with 15% $CaSO_4$.42H_2O$ added which produced the hardened material having the best compressive strength (300kg/$cm^2$) Also the low specific gravity(1, 2) of the hardened paste suggests the possibility that it can be used as a light-weight building material. The added $CaSO_4$.42H_2O$ constituted calcium-sulfo-aluminate hydrates which activates the formation of C-S-H hy-drates. Both hydrates developed the strength of hardened paste. The amount of calcium-sulfo-aluminate hydrates was increased when the $CaSO_4$.42H_2O$ was added over 15% however the increased amount did not help the development of strength because of the individually grown calcium-sulfo-aluminate hydrates.

• Journal of the Korean Ceramic Society
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• v.39 no.5
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• pp.473-478
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• 2002

${\alpha}-Al_2O_3$ platelets were synthesized by microwave heating the two different powder mixtures of $Al_2(SO_4)_3+2Na_2SO_4$ and ${\gamma}-Al_2O_3+2Na_2SO_4$ using flux method. DTA-TG, XRD and SEM were used to investigate the effect of microwave on the formation of ${\alpha}-Al_2O_3$ platelets. In the case of the mixture of $Al_2(SO_4)_3+2Na_2SO_4$, the microwave heated sample was ${\alpha}-Al_2O_3$ platelets composed of aggregates with smaller particle size compared to the conventionally heated sample. In the case of the mixture of ${\gamma}-Al_2O_3+2Na_2SO_4$, the temperature to form ${\alpha}-Al_2O_3$ platelets by the microwave heating was lower than that by the conventional heating and the morphology of the microwave heated sample was similar to that of the conventionally heated sample except that the microwave heated sample had smaller particle size compared to the conventionally heated sample.

• Journal of the Korean Magnetic Resonance Society
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• v.21 no.2
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• pp.67-71
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• 2017

At high temperature, the roles of $NH_4$ and $H_2O$ in $(NH_4)_2Fe(SO_4)_2{\cdot}6H_2O$ and $(NH_4)_2Zn(SO_4)_2{\cdot}6H_2O$ single crystals were investigated using a pulse NMR spectrometer. Temperature was shown to have a significant influence, causing changes in the deformation of $NH_4$ and $H_2O$. From the $^1H$ NMR and $^{14}N$ NMR spectrum, the forms of environment surrounding $^{14}N$ in $NH_4$ groups is more important than the loss of $H_2O$ groups. NMR studies indicate that $NH_4{^+}$ ions in Tutton salts play an important role in the changes of the crystal structure at high temperatures.

• Journal of the Korean Ceramic Society
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• v.21 no.2
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• pp.113-120
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• 1984

In this study a comparative investigation for the effect of $K_2SO_4$ and $CaSO_4$ on the decomposition of $C_3S$ was made. When pure $C_3S$ which was synthesized in the laboratory was mixed with $K_2SO_4$ and oxides such as MgO $Al_2O_3$ and $Fe_2O_3$ and then reburned at the temperature range between 135$0^{\circ}C$ and 145$0^{\circ}C$ no decompo-sition occurred, But when $CaSO_4$ and $Fe_2O_3$ were added to $C_3S$ and then reburned at below 130$0^{\circ}C$ $C_3S$ was partly decomposed to $C_2S$and CaO composing $2C_2S$.$CaSO_4$ When $CaSO_4$ and $Al_2O_3$were added $C_3S$ was entirely decomposed to $C_2S$ and CaO at 1300~140$0^{\circ}C$ but it was not decomposed at 145$0^{\circ}C$.

• Journal of Hydrogen and New Energy
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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.

• Atmosphere
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• v.27 no.1
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• pp.29-40
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• 2017

The $PM_{10}$ and $PM_{2.5}$ particles over the Yellow Sea of Korea were collected by ship-borne observation during two cruises in spring, 2015. Their water-soluble ionic components such as $NH_4^+$, $Na^+$, $K^+$, $Mg^{2+}$, $Ca^{2+}$, $SO_4^{2-}$, $NO_3^-$, $Cl^-$, $F^-$, $CH_3COO^-$, $HCOO^-$, and $CH_3SO_3^-$ were analyzed, in order to examine the pollution characteristics of the secondary aerosol components. The comparative study of particle size distribution has resulted that $NH_4^+$, $nss-SO_4^{2-}$, $nss-Mg2+$, $nss-K^+$, $HCOO^-$, and $CH_3SO_3^-$ species mostly existed in fine particle mode. Meanwhile, nss-F-and sea-salt species were distributed in both fine and coarse particle mode, $NO_3^-$, $nss-Ca^{2+}$, $CH_3COO^-$ species were rich in coarse particle mode. The concentrations of secondary pollutants($nss-SO_4^{2-}$, $NO_3^-$, $NH_4^+$) increased in fine particles, and those of natural components ($nss-Ca^{2+}$, Sea-salt) increased in coarse particles. $NH_4^+$ exists as the form of $(NH_4)_2SO_4$ and $NH_4NO_3$, and mostly as $(NH_4)_2SO_4$ in fine particles. $NH_4NO_3$ has lower content compared to $(NH_4)_2SO_4$, and it mostly existed in fine particles at Yellow Sea I and in coarse particles at Yellow Sea II. The concentration ratios of $NO_3^-/nss-SO_4^{2-}$ for Yellow Sea I and Yellow Sea II were 0.52 and 0.16 in coarse particles, and they were 0.64 and 0.38 in fine particles, respectively, showing that the stationary source emissions were more important than mobile source emissions in Yellow Sea II (except Passage II-4).

• Journal of the Korea Concrete Institute
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• v.27 no.2
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• pp.95-102
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• 2015

In this paper, the effects of sodium hydroxide (NaOH) and aluminum potassium sulfate ($AlK(SO_4)_2{\cdot}12H_2O$) dosage on strength properties were investigated. For evaluating the property related to the dosage of alkali activator, sodium hydroxide (NaOH) of 4% (N1 series) and 8% (N2 series) was added to 1~5% (K1~K5) dosage of aluminum potassium sulfate ($AlK(SO_4)_2{\cdot}12H_2O$) and 1% (C1) and 2% (C2) dosage of calcium oxide (CaO). W/B ratio was 0.5 and binder/ fine aggregate ratio was 0.5, respectively. Test result clearly showed that the compressive strength development of alkali-activated slag cement (AASC) mortars were significantly dependent on the dosage of NaOH and $AlK(SO_4)_2{\cdot}12H_2O$. The result of XRD analysis indicated that the main hydration product of $NaOH+AlK (SO_4)_2{\cdot}12H_2O$ activated slag was ettringite and CSH. But at early ages, ettringite and sulfate coated the surface of unhydrated slag grains and inhibited the hydration reaction of slag in high dosage of $NaOH+AlK(SO_4)_2{\cdot}12H_2O$. The $SO_4{^{-2}}$ ions from $AlK(SO_4)_2{\cdot}12H_2O$ reacts with CaO in blast furnace slag or added CaO to form gypsum ($CaSO_4{\cdot}2H_2O$), which reacts with CaO and $Al_2O_3$ to from ettringite in $NaOH+AlK(SO_4)_2{\cdot}12H_2O$ activated slag cement system. Therefore, blast furnace slag can be activated by $NaOH+AlK(SO_4)_2{\cdot}12H_2O$.