• Journal of the Korean Institute of Telematics and Electronics
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• v.19 no.6
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• pp.52-54
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• 1982

p·Si-전해질 접합을 전해질로 6N H2SO4, 6N H2SO4(Ti3+), 6N H2SO4(Ti4+), 6N H2SO4(Ti4+/Ti3+)을 사용하여 만들었다. 이들 전해질중 6N H2SO4(Ti4-/Ti3+)을 사용할 때 p·Si 광음극이 안정하게 동학하며 높은 광전 감도를 가지고 있었다. p·Si-electrolyte junction are prepared by using p·Si photocatode in four different electrolytes such as 6N H2SO4, 6N H2SO4(Ti3+), 6N H2SO4(Ti4+), 6N H2SO4(Ti4+/Ti3+) respectively. Among those electrolytes 6N H2SO4(Ti4-/Ti3+) shows very good results, in which p·Si photocathode is stable.

• Resources Recycling
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• v.11 no.1
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• pp.26-31
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• 2002

The recovery of $H_2$$SO_4$from sulfuric acid waste was attempted by a diffusion dialysis method using an anion extchange membrane. The effect of flow rate, temperature, concentration of metal ions on the recovery rate was studied. The recovery of $H_2$$SO_4$decreased with the concentration of $H_2$$SO_4$and flow rate. The recovery increased with the flow rate ratio of water/$H_2$$SO_4$solution upto 1 above which no further increase was observed. The flow rate did not affect the rejection of Fe and Ni ions. As a result, about 80% of $H_2$$SO_4$could be recovered from sulfuric acid wastes which contains 4.5M free$-H_2$$SO_4$at the flow rate of 0.26 $1/hr-m^2$. The concentration and purity of recovered $H_2$$SO_4$was 4.3M and 99.8%, respectively.

• Resources Recycling
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• v.11 no.1
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• pp.19-25
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• 2002

For $ZnSO_4$-$Na_2$$SO_4$-$H_2$ $SO_4$-$NaOH-H_2$O system, pH of solutions with different electrolyte concentrations was measured at $25^{\circ}C$ and ionic equilibria were analyzed by using K-value method. Activity of water and activity coefficients of solutes were calculated by Pitzer equation. The equilibrium concentration and activity coefficients of solutes were calculated from initial experimental conditions. At high ionic strength of 4m, the pH values calculated were in good agreement with those measured. In the experimental ranges of ionic strength of solution from 3.5 to 4.3 m, the mean activity coefcient of $ZnSO_4$calculated agreed well with those obtained from literature.

• Analytical Science and Technology
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• v.16 no.2
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• pp.159-165
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• 2003

To develop an ionic equilibria model applicable to the sulfuric acid leaching solutions of zinc oxide ore, the method of the Pitzer equation and that of the Vasil'ev equation were compared. As the ionic strength of the solution increased to 9 m, the results of ionic equilibria by the Pitzer equation were more accurate than those by Vasil'ev. To simulate the sulfuric acid leaching solutions of zinc oxide ore, the mixed solutions with the various composition of $ZnSO_4-Fe_2(SO_4)_3-Na_2SO_4-H_2SO_4-NaOH-H_2O$ were prepared. The pH values calculated in this study agreed well with those measured at $25^{\circ}C$.

• Applied Biological Chemistry
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• v.6
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• pp.57-59
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• 1965

According to the result of the observations on the effect of the reagents, $CuSO_4{\cdot}5H_2O$, $ZnSO_4{\cdot}7H_2O$ $MnSO_4{\cdot}4H_2O$, $HgCl_2$, upon the mycelial growth of psalliota campestris $HgCl_2$ showed the strongest effect on checking the mycelial growth $(,.008{\sim}0.01%)$ $CuSO_4{\cdot}5H_2O(0.030%)$, $ZnSO_4{\cdot}7H_2O(0.080%)$, came next and the $MnSO_4{\cdot}4H_2O(0.100%)$ was the weakest. Writer also found that showed the promoting effect of the mycelial growth in appropriate Concentration (at $0.015%\;CuSO_4{\cdot}5H_2O$, $0.030%ZnSO_4{\cdot}7H_2O$).

• KSBB Journal
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• v.5 no.4
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• pp.355-363
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• 1990

Methanol-utilizing bacterium isolated from sewage samples in Seoul showed optimal temperature and pH of $33^{\circ}C$ and 7.1 for growth, respectively. The maximum specific growth rate was $0.42hr^{-1}$. The minimum medium composition was reconstituted depending on the surplus and the deficit of each component in the basal medium at steady state. The optimal composition was given as(g/l); Methanol 40, $(NH_4)_2\;SO_42, \;KH_2PO_4\;1.5, \;K_2HPO_4\;0.2, \;H_3PO_4\;0.79, \;Na_2HPO_4{\cdot}12H_2O\;0.15, \;MgSO_4{\cdot}7H_2O\;1.5, \;FeSO_4{\cdot}7H_2O\;0.034, \;MnSO_4{\cdot}4H_2O\;0.005, \;CuSO_4{\cdot}5H_2O\;0.0027, \;CaCl_2{\cdot}2H_2O\;0.25, \;ZnSO_4{\cdot}7H_2O\;0.007, \;(NH_4)_6\;Mo_7O_{24}{\cdot}4H_2O\;0.00048, \;H_3BO_3\;0.00068, \;CoCl_2\; 0.00024$ Under the continuous culture with optimum medium the maximum cell productivity was 3.8g/1/hr at dilution rate $0.23hr^{-1}$. Maximum cell concentration and its protein content were 19.5g/l and 70% at dilution rate of $0.1hr^{-1}$, respectively.

• Korean Chemical Engineering Research
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• v.44 no.4
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• pp.410-416
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• 2006

For highly efficient operation of a Bunsen process section in an iodine-sulfur thermochemical hydrogen production cycle using nuclear heat, the process characteristics of $H_2SO_4-HI-H_2-O-I_2$ mixture system for separating into two liquid phases ($H_2SO_4$-rich phase and $HI_x$-rich phase) and the distribution of $H_2O$ to each phase were investigated.The experiments for process variables were carried out in the temperature range, from 298 to 353 K, and in the $H_2SO_4/HI/H_2O/I_2$ molar ratio of 1/2/14~20/0.5~8.0. As the results, for the $SO_2-I_2-H_2O$ Bunsen reaction system, the ranges between the starting point and the saturation point for two liquid phases separation were determined by calculation. The best result for the minimization of impurities (HI and $I_2$ in $H_2SO_4$ phase and $H_2SO_4$ in $HI_x$ phase) in each phase was obtained in an optimum condition with the highest temperature of 353 K and the highest $I_2$ molar composition. In this condition, the $HI/H_2SO_4$ molar ratio in the $H_2SO_4$-rich phase and the $H_2SO_4/HI_x$ molar ratio in the $HI_x$-rich phase were 0.024 and 0.028, respectively. For the distribution of $H_2O$ to each phase, it is appeared that the affinity between $HI_x$ and $H_2O$ was more superior to that between $H_2SO_4$ and $H_2O$. The affinity between $HI_x$ and $H_2O$ was decreased with increasing temperature but increased with increasing $I_2$ molar composition.

• Korean Chemical Engineering Research
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• v.44 no.4
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• pp.356-362
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• 2006

The $SO_2$ reduction using CO and $H_2$ over Sn-Zr based catalysts was performed in this study. Sn-Zr based catalysts with Sn/Zr molar ratio (0/1, 1/4, 1/1, 2/1, 3/1, 1/0) were prepared by the precipitation and co-precipitation method. The effect of the temperature on the reaction characteristics of the $SO_2$ reduction with a reducing agent such as $H_2$ and CO was investigated under the conditions of space velocity of $10,000ml/g_{-cat.}h$, $([CO(or\;H_2)]/[SO_2])$ of 2.0. As a result, the activity of Sn-Zr based catalysts were higher than $SnO_2$ and $ZrO_2$. The reactivity for the $SO_2$ reduction with CO was higher than that with $H_2$, and sulfur yield in the $SO_2$ reduction by $H_2$ was higher than that by CO. The reactivity for the $SO_2$ reduction with $H_2$ was increased with the reaction temperature regardless of Sn-Zr based catalyst with a Sn/Zr molar ratio. $SnO_2-ZrO_2$ (Sn/Zr=1/4) had highest activity at $550^{\circ}C$, in the $SO_2$ reduction with $H_2$ and $SO_2$ conversion of 94.4％ and sulfur yield of 66.4％ were obtained at $550^{\circ}C$. On the other hand, in the $SO_2$ reduction by CO, the reactivity was decreased with the increase over $325^{\circ}C$. At the optimal temperature of $325^{\circ}C$, $SO_2$ conversion and sulfur yield were about 100％ and 99.5％, respectively, in the $SO_2$ reduction over $SnO_2-ZrO_2$ (Sn/Zr=3/1). Also, the $SO_2$ reduction using syngas with $CO/H_2$ ratio over $SnO_2-ZrO_2$ (Sn/Zr=2/1) was performed in order to investigate the application possibility of the simulated coal gas as the reductant in DSRP. As a result, the reactivity of the $SO_2$ reduction using syngas with $CO/H_2$ ratio was increased with increasing the CO content of syngas. Therefore, it could be known that DSRP using the simulated coal gas over Sn-Zr based catalyst is possible to be realized in IGCC system

• Applied Chemistry for Engineering
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• v.29 no.1
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• pp.56-61
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• 2018

In Bunsen reaction section for the integrated operation of sulfur-iodine (SI) process, $I_2$ and $H_2O$ reactants are supplied as dissolved species in an $HI_x$ solution. Most of the $H_2SO_4$ product is found in the $HI_x$ phase when Bunsen reaction is performed using the $HI_x$ solution and $SO_2$ feed, so that the volume ratio of the $H_2SO_4$ phase to the $HI_x$ phase is very low. In this study, we investigated the effects of ultrasound irradiation on Bunsen reaction using the $HI_x$ solution to improve its phase separation performance. With ultrasound irradiation, the amount of $H_2SO_4$ moved to the $H_2SO_4$ phase from the $HI_x$ phase increased by up to 58.0 mol% and the volume of $H_2SO_4$ phase also increased by up to 13.1 vol%. In particular, the effect of ultrasound irradiation on the phase separation was improved with decreasing operating temperature, $I_2$ and $H_2O$ feed concentrations. The ultrasound irradiation induces the formation of additional $H_2O$ molecules by shifting microscopically the reaction equilibrium in the $HI_x$ phase. Afterward, the additionally generated $H_2O$ and isolated $H_2SO_4$ molecules form more $H_2SO_4{\cdot}xH_2O$ (x = 5-6) clusters that can be moved to the $H_2SO_4$ phase.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.75-82
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• 1996

Acrylic acid was graft-copolymerized on polyethylene film in the presence of additives such as acid and $FeSO_4(NH_4)_2SO_4{\cdot}6H_2O$ using peroxide grafting technique by ${\gamma}$-ray and electron beam, and the effect of $FeSO_4(NH_4)_2SO_4{\cdot}6H_2O$ and acid on the grafting yield was evaluated. The grafting mechanism and the physical property of grafted films were also examined. The results showed that the inclusion of $FeSO_4(NH_4)_2SO_4{\cdot}6H_2O$ in acidified acrylic acid grafting solution was extremely beneficial and led to a most unusual enhancement effect in the radiation grafting. In the other hand, inclusion of mineral acid in the grafting solution in the absence of $FeSO_4(NH_4)_2SO_4{\cdot}6H_2O$ could not lead to he suitable grafting reaction by the severe homopolymerization of acrylic acid. The addition of $H_2SO_4$, and HCl led to much higher grafting yield than $HNO_3$and $CH_3COOH$. It was shown that grafting yield of ${\gamma}$-ray irradiated-polyethylene was higher than that of electron beam irradiated polyethylene.