• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.304-307
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• 2005

Printed circuit boards (PCBs) of the printer are composed of various organic and inorganic compounds as well as metals and alloys. This study was conducted to recover valuable metals from used PCBS by physical separation and leaching. The PCBs was crushed, sieved, classified by zig zag classifier and magnetic constituents were removed by the magnetic separation. The non-magnetic constituents of sizes between 1.2 and 0.6 mm especially containing high quantity of Cu (e.g. 83% on metal base and 31% on total base) were used for the leaching experiment. The effect of the nature and concentration of acids and reaction temperature were investigated. The Cu leaching rate to 98.5% in 2M nitric acid, pulp density 100g/L, $90^{\circ}C$, 300rpm, 1hr leaching.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1995.10a
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• pp.16-19
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• 1995

Effects of the changes in bottom topography and non-linearity of the western boundary current on the separation position of the Tsushima Warm Current(TWC) are investigated using a primitive equation model in a simplified model domain which consists of a deep ocean, a continental shelf and a marginal sea(Fig. 1). (omitted)

• Journal of Industrial Technology
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• v.19
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• pp.343-350
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• 1999

The separation of humic acid by ultrafiltration was most influenced by pressure difference. when pressure difference increased from latm to 3atm, permeate flux increased from 40% to 60% but rejection rate reduced from 97% to 91% because of adsorption of molecules of humic acid at membrane surface. Since physical adsorption was more dominant than chemical adsorption, adsorption of membrane surface was reduced 50% when slow rate increased at same conditions.

• Macromolecular Research
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• v.12 no.1
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• pp.11-21
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• 2004

Toughening of epoxy resins for improvement of crack resistance has been the subject of intense research interest during the last two decades. Epoxy resins are successfully toughened by blending with a suitable liquid rubber, which initially remains miscible with epoxy and undergoes a phase separation in the course of curing that leads to the formation of a two-phase microstructure, or by directly blending preformed rubbery particle. Unlike the situation for thermoplastics, physical blending is not successful for toughening epoxy resins. Recent advances in the development of various functionalized liquid rubber-based toughening agents and core-shell particles are discussed critically in this review.

• Electrical & Electronic Materials
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• v.9 no.8
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• pp.813-818
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• 1996

Amorphous As$_{10}$Ge$_{15}$ Te$_{75}$ device shows the memory switching characteristics under d.c. bias. In bulk material, a-As$_{10}$Ge$_{15}$ Te$_{75}$ switching threshold voltage (V$_{th}$) is very high (above 100 volts), but in the case of thin film, V$_{th}$ decreases to a few or ten a few volts. The characteristics of V$_{th}$ depends on the physical dimensions such as the thickness of thin film and the separation between d.c. electrodes, and the annealing conditions. The switching threshold voltage decreases exponentially with increasing annealing temperature and annealing time, but increases linearly with the thickness of thin film and exponentially with increasing the separation between d.c. electrodes. The desirable low switching threshold voltage, therefore, can be obtained by the stabilization through annealing and changing physical dimensions.imensions.sions.

• Resources Recycling
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• v.15 no.6 s.74
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• pp.48-55
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• 2006

This study was carried out for establishing the physical recycling technique for commercializing process on household batteries. The procedure involves shape separator, crushing, magnetic separation, classification and eddy current separation in sequence. The separation capacity was 400-600 unit cell/hr with shape separation system. The impurities such as manganese and zinc in the magnetic product were below 0.1% respectively, the concentration of iron was above 99% in spent carbon zinc battery. Also non-magnetic products are composed of 22-30% En, 16-22% Mn, 1-3% Fe in the case oi spent zinc carbon battery. The amounts of other components such as carbon rod, plastics and separator were about 37-50%. From the eddy current separation of nonferrous products, the plate-type zinc components were separated up to 96% with 2,250-2,750 meter/min of the conveyor speed.

• The Korean Journal of Rheology
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• v.1 no.1
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• pp.12-19
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• 1989

Polymer fluid flow and polymerization reaction occur simultaneously during the reactive polymer processing. The viscosity and physical properties change as thereaction proceeds and the crystallization and vitrifica-tion occur as the T,,,and the Tg of the polymerizing fluid exceeds the reaction temperature within the mold.

• Proceedings of the Petrological Society of Korea Conference
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• 2009.05a
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• pp.26-28
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• 2009

• Journal of Korean Society of Water and Wastewater
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• v.27 no.5
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• pp.621-629
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• 2013

Since algae had been issued an environmental problem, water blooms, deepened due to increase of retention water basin in Korea as well as a biomass resource for producing biofuel, this study conducted a series of experiments for Spirulina platensis using the flotation process with micro-bubble. To elevate utilization of collected-algae, this study focused on omitting or minimizing coagulant's doses as changing a cultivation period and condition affected on physical property change of algae. Two coagulants, PAC and Chitosan, were used to test the collecting rate of algae and the result found no difference between two rates. For flotation experiments without adding the coagulant, dried algae weight (passing 14 days after cultivation for 20 days) detected high separation efficiency 98.2 % and it (passing 7 days after long-term cultivation for 28 days) presented good separation efficiency 91.9 %. Chlorophyll's separation efficiency showed a similar tendency with the case of the dried algae weight. In endogeny conditions, a light source and a carbon source were not considerably affected on the flotation separation efficiency. Thus, this study confirms that algae biomass may be collected without the coagulant during the endogeny condition period after enough cultivation time, 3 weeks.

• Membrane Journal
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• v.33 no.1
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• pp.1-12
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• 2023

In this review, surface modification methods of hydrophobic poly(tetrafluoroethylene) (PTFE) membrane are introduced and their improved hydrophilicity results are discussed. Fluoropolymer based membranes, represented by PTFE membranes have been used in various membrane separation processes, including membrane distillation, oil separation and gas separation. However, despite excellent physical properties such as chemical resistance, heat resistance and high mechanical strength, the strong hydrophobicity of PTFE membrane surface has become a challenging factor in expanding its membrane separation application. To improve the separation performance of PTFE membranes, wet chemical, hydrophilic coating, plasma, irradiation and atomic layer deposition are applied, modifying the surface property of PTFE membranes while maintaining their inherent properties.