• Applied Chemistry for Engineering
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• v.28 no.2
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• pp.206-213
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• 2017

The adsorption of crystal violet dyes from aqueous solution using the granular activated carbon was investigated. Adsorption experiments were carried out as a function of the adsorbent dose, initial concentration, contact time and temperature. The adsorption characteristic of crystal violet followed Langmuir isotherm. Based on the estimated Langmuir separation factor ($R_L=0.02{\sim}0.106$), this process could be employed as an effective treatment (0 < $R_L$ < 1). The adsorption kinetics followed the pseudo second order model. The values of Gibbs free energy (-1.61~-11.66 kJ/mol) and positive enthalpy (147.209 kJ/mol) indicated that the adsorption process is a spontaneous and endothermic reaction. The isosteric heat of adsorption decreased with increasing of surface loading by the limited adsorbent-adsorbate interaction due to increased surface coverage.

• Journal of Sensor Science and Technology
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• v.29 no.1
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• pp.27-32
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• 2020

This study proposes a pixel-patterning method for organic light-emitting diodes (OLEDs) based on thermal transfer. An infrared lamp was introduced as a heat source, and glass type donor element, which absorbs infrared and generates heat and then transfers the organic layer to the substrate, was designed to selectively sublimate the organic material. A 200 nm-thick layer of molybdenum (Mo) was used as the lightto-heat conversion (LTHC) layer, and a 300 nm-thick layer of patterned silicon dioxide (SiO₂), featuring a low heat-transfer coefficient, was formed on top of the LTHC layer to selectively block heat transfer. To prevent the thermal oxidation and diffusion of the LTHC material, a 100 nm-thick layer of silicon nitride (SiN_x) was coated on the material. The fabricated donor glass exhibited appropriate temperature-increment property until 249 ℃, which is enough to evaporate the organic materials. The alpha-step thickness profiler and X-ray reflection (XRR) analysis revealed that the thickness of the transferred film decreased with increase in film density. In the patterning test, we achieved a 100 ㎛-long line and dot pattern with a high transfer accuracy and a mean deviation of ± 4.49 ㎛. By using the thermal-transfer process, we also fabricated a red phosphorescent device to confirm that the emissive layer was transferred well without the separation of the host and the dopant owing to a difference in their evaporation temperatures. Consequently, its efficiency suffered a minor decline owing to the oxidation of the material caused by the poor vacuum pressure of the process chamber; however, it exhibited an identical color property.

• Transactions of Materials Processing
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• v.6 no.3
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• pp.239-249
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• 1997

The behaviour of alloys in the semi-solid state strongly depends on the imposed stress state and on the morphology of the phase which can vary from dendritic to globular. To optimal net shape forging of semi-solid materials, it is important to investigate for filling phenomena in forging process of arbitrarily shaped dies. To produce a automotive part which has good mechanical property, the filling pattern according to die velocity and solid fraction distribution has to be estimated for arbitrarily shaped dies. Therefore, the estimation of filling characteristic in the forging simulation with arbitrarily shaped dies of semi-solid materials are calculated by finite element method with proposed algorithm. The proposed theoretical model and a various boundary conditions for arbitrarily shaped dies is investigated with the coupling calculation between the liquid phase flow and the solid phase deformation. The simulation process with arbitrarily shaped dies is performed to the isothermal conditions of two dimensional problems. To analysis of forging process by using semi-solid materials, a new stress-strain relationship is described, and forging analysis is performed by viscoelastic model for the solid phase and the Darcy's law for the liquid flow. The calculated results for forging force and filling limitations will be compared to experimental data. The filling simulation of simple products performed with the uniform billet temperature(584$^{\circ}C$) from the induction heating by the commercial package MAGMAsoft. The initial step of computation is the touching of semi-solid material with the end of die gate and the initial concept of proposed system just fit with the capability of MAGMAsoft.

• Journal of Soil and Groundwater Environment
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• v.12 no.6
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• pp.70-77
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• 2007

Pseudomonas sp. KM1 was separated from soil contaminated by petroleum and identified. The isolated strain is Gram-positive, rod-shaped and immotile. In batch culture, the optimum cultivation temperature and pH was $35^{\circ}C$ and 7, respectively. Biodegradation of PAHs experiment with soil slurry system was performed using Pseudomonas sp. KM1. Pseudomonas sp. KM1 could degrade 7 PAHs including naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, pyrene, and fluoranthene. These mixed PAHs was easily degraded within one day except fluoranthene, which was degraded much slowly, taking several days by this isolated bacteria. Pseudomonas sp. KM1 is good candidate for bioremediation of PAHs contaminated soils. Biodegradation rates of naphthalene, phenanthrene and pyrene in soils were different at each soil, and the rates were decreased as sorption capacity increased.

• Journal of the Korean Applied Science and Technology
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• v.30 no.1
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• pp.183-196
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• 2013

The purpose of this study is to process a seaweed resources that is easy to find in Korea and has outstanding phlogistone and high yield seaweed vinegar solution through mass-production and facility development for utilization. The compound uses wasted seaweeds, such as brown seaweed, kelp, seaweed fusiform, and laver, and carbonizes them in high temperature by drying in poly step trap to extract them. In also involves the development of a process that separates and refines the extracts to create a high value-added anti-bacterial bio solution that can replace chemicals in agriculture and industries and even chemical food additives. so, studied separation and refining of seaweed extracts to analyze the compounds. and processed and compared to seaweed vinegar extracts to prove superiority.

• Membrane Journal
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• v.27 no.5
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• pp.458-467
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• 2017

In this study, we prepared PVDF membranes via TIPS for water treatment applications. PVDF was used for its excellent chemical and mechanical properties. The effect of coagulation bath composition, temperature, and heat capacity on the overall membrane morphology was studied and observed using SEM. A mixture of DOP and DBP was used as the diluent, and silica was used as an additive. It was observed that as the heat capacity of the coagulation bath increased, the crystallization rate of PVDF decreased yielding larger pores. Also, as the heat capacity of the coagulation bath decreased, the crystallization rate of PVDF increased yielding smaller pores.

• KSBB Journal
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• v.22 no.3
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• pp.174-178
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• 2007

The aim of this study was to identifyisothiocyanates (ITCs) from wasabi (Wasabi japonica Matsum) using supercritical carbon dioxide ($SCO_2$) and to compare the composition in the extracts between $SCO_2$ and organic solvents extraction. A semi-continuous high pressure apparatus was used to extract wasabi (roots, stems and leaves) at following conditions pressure 80$\sim$120 bar, temperature $40\sim50^{\circ}C$. Ether, ethanol, chloroform and dichloromethane were used as organic solvents. The ITCs extracted by means of both separation technologies were analyzed by a gas chromatography system. As the results of study, AITC and ITCs were highly extracted at 40$^{\circ}C$ and 80 bar. To extract AITC from wasabi, $SCO_2$ extraction is more effective than organic solvents extraction, resulted in thermal degeneration and remaining of organic solvents.

• KSBB Journal
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• v.19 no.3
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• pp.169-173
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• 2004

The Rhodiola Sachalinensis 5 g were mixed and extracted with methanol 150 $m\ell$ at the room temperature for 12 h. The effluents were collected and grouped into the two. Un this experimental condition, the mobile phase composition were linearly changed as follows; water/methanol : 90/10 - 30/70 (vol. %, for 5 min), 30/70 - 10/90 (vol. %, for 15 min) and an analytical column (3.9 ${\times}$ 25 em, 15 $\mu\textrm{m}$ particle size, and 300 ${\AA}$ pore size) was utilized. The performance of the extracted Rhodiola Sachalinensis as a whitening agent was not favorable, so it classifies the Rhodiola Sachalinensis extractions with two fractions and collects each fraction for whitening agent assay. For the in-vivo melanin production ratio assay that used melanin-a cell in 10 ppm concentration, it was 58.6%, the first fraction of the effluents collected between 1.0 and 4.0 min, while it was 60％ between 10.4 and 17.6 min for the second fraction, which were more efficient than that of arbutin, 45.6%.

• Resources Recycling
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• v.11 no.4
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• pp.44-50
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• 2002

Characteristics on the sulfuric acid leaching of zinc and manganese from the spent zinc-carbon battery powders obtained by cushing and magnetic separation, were investigated with the variation of sulfuric acid concentration, reaction temperature, stir-ring speed and solid/liquid ratio. The sample powders were composed of Zn metal, ZnO, $MnO_2$ and $Mn_2$$O_3$. and it was found that the selective leaching of zinc was difficult in this system. At the condition of S/L ratio 1:10, IM H$_2$$SO_4$, $60^{\circ}C$ and 200 rpm, leaching rate of Zn and Mn are 92% and 35% respectively. The concentration of Zn and Mn in the leaching solution are 19.5 g/l, 7.8 g/l and pH of that solution is 0.75. It was confirmed at reducing agent should be added to increase e leaching rate of manganese with sulfuric acid.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.268-275
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• 2020

In domestic mountain resort areas, a catenary system cannot be installed for the protection of the natural environment and view. Therefore, mountain trams must be operated wireless. In this study, a local ground pantograph, which supplies electricity to the battery on board, was developed for this purpose, and its performance was verified by tests. The system is installed on ground at stops or repair shops. While a bogie goes to the pantograph, the arms and collection shoes are raised by a spring force to make contact with the collection bar under the bogie so electric power can be supplied to the battery. Because it is a local ground type, it does not require a roof pantograph and catenary system. The system enables the mountain tram to run wireless. In addition, there is no separation and arc because it collects current while standing at stops or shops. The system has a long life because moving contact, which generates wear and damage to shoes, is avoided. The insulation resistance was above the criteria of 10 ㏁, and there was no abnormal temperature increase when a current of 335A was supplied for one hour.