• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.1
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• pp.8-13
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• 2007

In MIS capacitor structure, we have studied the electrical properties in Ammonium Sulfide solution treatment while AIN thin film as a insulator is being formed by reactive sputtering method. The deposition process conditions of AIN thin film we temperature $250^{\circ}C$, DC Power 150 W, pressure 5 mTorr and 8 sccm(Ar : 4 sccm, $N_{2}$ : 4 sccm). The surface of GaAs was treated with Ammonium Sulfide solution, it was shown the leakage current was less than $10^{-8}\;A/cm^{2}$. The deep depletion phenomena of inverse area with treating Ammonium Sulfide solution in C-V analysis was improved as compared the condition of without Ammonium Sulfide solution and hysteresis property as well.

• Resources Recycling
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• v.28 no.5
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• pp.51-59
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• 2019

This study focused on the synthesis of the nickel hydroxide using ammonium sulfate in leaching solution from waste nickel-cadmium batteries. The effect of pH, temperature and the input amount of ammonium sulfate in leaching solution was investigated. The ammonium nickel sulfate with high purity was obtained in acidic leaching solution and the solution temperature of $60^{\circ}C$. The suitable molar ratio of the input amount of ammonium sulfate to nickel in solution is 2:1. The impurity about 1.4 at.% of Cd was included in the nickel hydroxide precipitates when ammonium nickel sulfate was used. At the process using sodium sulfide which precipitates the cadmium in solution, nickel and iron compounds were precipitated together.

• 한국해양학회지
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• v.28 no.3
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• pp.229-240
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• 1993

This study investigated the behaviour of sulfur species after the early diegenetic reduction of sulfate from pore solution in an anoxic intertidal flat deposit in the Banweol area of Kyeong-gi Bay, west coast of Korea. A total of seven sediment cores were collected during 1990∼1992 and were analyzed for their solid-phase sulfur species (acid-volatile sulfur, element sulfur, pyrite sulfur) as well as for chemical components in the pore solution, such as sulfate, ammonium, hydrogen sulfide, phosphate and Fe ion. The pore water sulfate oncentration was found to decrease rapidly downward from the sediment surface, while that of hydrogen sulfide, ammonium and phosphate showed and increase. The dissolved iron concentration in pore water, on the other hand, was found high in the surface layer of sediment, but fell sharply below this layer. these characteristic profiles of pore water sulfide and iron concentrations suggest that some reaction occurs between dissolved iron and sulfide ions, leading to the formation of various sulfide minerals in the sedimentary phase. The amount of inorganic sulfur species in the sediment increased downward, and showed a maximum of up to 7.9 mg/g. among the three species analyzed, acid-volatile sulfur (AVS) was dominant comprising more than 50% of the total. The amount of pyrite sulfur was greater than that of element sulfur. This implies that the formation of pyrite was restricted in this environment. the limited amount of element sulfur in this deposit may have discouraged the active formation of pyrite.

• Polymer(Korea)
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• v.39 no.1
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• pp.88-98
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• 2015

4-Amino-N-hexadecylbenzamide-graphene sheets (AHB-GSs), used in the preparation of the polyimide (PI) nanocomposite films, were synthesized by mixing a dispersion of graphite oxide with a solution of the ammonium salt of AHB. The atomic force microscope image of functionalized-GS on mica and a profile plot revealed the average thickness of AHB-GS to be ~3.21 nm. PI films were synthesized by reacting 4,4'-biphthalic anhydride and bis(4-aminophenyl) sulfide. PI nanocomposite films containing various contents of AHB-GS over the range of 0-10 wt% were synthesized using the solution intercalation method. The PI nanocomposite films under different thermal imidization temperatures, 250 and $350^{\circ}C$, were examined. The graphenes, for the most part, were well dispersed in the polymer matrix despite some agglomeration. However, micrometer-scale particles were not detected. The average thickness of the particles was <10 nm, as revealed from the transmission electron microscope images. Only a small amount of AHB-GS was required to improve the gas barrier, and electrical conductivity. In contrast, the glass transition and initial decomposition temperatures of the PI hybrid films continued to decrease with increasing content of AHB-GS up to 10 wt%. In general, the properties of the PI hybrid films heat treated at $350^{\circ}C$ were better than those of films heat treated at $250^{\circ}C$.