• Membrane and Water Treatment
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• v.6 no.2
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• pp.95-102
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• 2015

The presented research is about characterization of Cellulose Triacetate (CTA) based Polymer Inclusion Membranes (PIMs) which incorporated the commercial extractant Aliquat 336, Tributylphosphate (TBP) as modifier and 2-Nitro Phenyl Pentyl Ether (NPPE) as plasticizer, for the preparation of the membranes. Chemical and physical characteristics of the synthesized membranes especially membrane thickness and side difference effects were investigated. Different surface structures and membrane thickness affect the extraction efficiency of membranes. Membrane extraction experiments were studied where the glass-facing surface of the membranes placed next to feed phase and the air-facing surface to stripping phase. The membrane was characterized by means of AFM, FT-IR and SEM.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.4
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• pp.137-146
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• 1996

This paper presents the results of field experience from an experimental pavement construction on a low volume road using recycled concrete. The recycled concrete was prepared by replacing a half of coarse aggregate with recycled aggregate. Virgin natural sand was used as fine aggregate together a plasticizer and a fly ash (0.8% and 5% by wt. of cement, respectively). The load bearing capacity of the subbase made of recycled aggregate was acceptable. The length, thickness and width of the pavement were l00m, 20cm and 3m, respectively. From construction experience, it was found that workability and finishability of the recycled concrete mixture were relatively poor, but strengths were satisfactory. Flexural strength, compressive strength and elastic modulus at 28 days were 54Kg/$cm^2$, over 250Kg/$cm^2$, and 220,OOOKg/$cm^2$, respectively. The construction could be performed by hand without much difficulty. The surface was finished smoothly by wet fabric and only minor cracks were found on the surface.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.121-124
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• 1998

The purpose of this study is to research and develop solid polymer electrolyte(SPE) for Li secondary battery. This paper describes temperature dependence of conductivity, impedance spectroscopy, electrochemical properties of PVDF electrolytes as a function of a mixed ratio. Polyvinylidene(PVDF) based polymer electrolyte films were prepared by thermal gellification method of preweighed PVDF, plasticizer and Li salt. The conductivity of PVDF electrolytes was 10$\^$-3/S/cm. 25PVDFPC$\_$10/EC$\_$10/LiClO$_4$ electrolyte shows the better conductivity of the others. 25PVDFPC$\_$10/EC$\_$10/LiClO$_4$electrolyte remains stable up to 4.7V vs. Li/Li$\^$+/. Steady state current method and ac impedance used for the determination of transference numbers in PVDFD electrolyte film. The transference number of 25PVDFPC$\_$10/EC$\_$10/LiClO$_4$electrolyte is 0.58.

• Bulletin of the Korean Chemical Society
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• v.29 no.1
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• pp.165-167
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• 2008

The performances of tetracycline based cation selective polymeric membrane electrodes of many sets with different plasticizers were investigated as the selectivity of ion-selective electrodes and optodes are greatly influenced by membrane solvent and also controlled by plasticizers. The membrane 1 with Bis(2-ethylhexyl) sebacate (DOS) and additive shows good potentiometric performance toward Ca2+ (slope: 27.8 mV per decade; DL: -4.52) including selectivity. Contrastingly, membrane 4 with Dibutyl phthalate (DBP) shows near-Nernstian response, it has also shown the best measuring range and detection limit for Ca2+ (29.5 mV and -5.10) and Mg2+ (24.4 mV and -5.04) and the least selectivity has been also observed between Ca2+ and Mg2+. When the membrane 1 and 4 were used together to flow system, we could determine the concentration of Ca2+ and Mg2+, simultaneously.

• Journal of the Korean Society of Tobacco Science
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• v.22 no.2
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• pp.157-163
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• 2000

Filter hardness is important to filter and cigarette manufactures because it is directly related to the ability of a plugmaker during making filter and to the acceptability of the filter by the consumer. In general, glycerol triacetate(Triacetin, TA) is the currently used common plasticizer in making filters from cellulose acetate tow and the effect of triacetin on hardness of filter which is made of mono cellulose acetate tow was well known. But unfortunately, the effect of triacetin on the hardness of cellulose acetate filter containing ativated carbon(carbon filter) was not reported so far. In this study, we manufactured filters with various carbon content at different triacetin concentrations and then analyzed the filter hardness and pressure drop. Filter hardness was directly increased with triacetin concentration but pressure drop was not affected and the effect of carbon content on filter hardness was smaller than that of triacetin concentration. However, pressure drop was directly increased with carbon content.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.415-418
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• 2005

Nowadays the three major commercially available of organic chemical admixtures are modified lignosulfonates(LS), sulfonated naphthalene-formaldehyde resins (SNF) and sulfonated melamine-formaldehye (SMF). In this study, various sulfonated melamine-formaldehyde (SMF) superplasticizers were synthesized via four synthetic steps. Hydroxymethylation (Step 1), Sulfonation (Step 2), Polymerization (Step 3) and Neutralization and Stabilization (Step 4). In this synthesis of SMF, reaction conditions such as the mole ratio of melamine to formaldehyde and the amount of acid catalyst were changed. After application of SMF superplasticizer to cement paste and mortar, the physical properties including workability, slump loss, compressive strength were compared.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.33-36
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• 2006

In manufacturing Ultra high strength fiber reinforced concrete(UHSFRC), steel fiber, super-plasticizer and silica fume are important but they are imported materials therefore very expensive. consequently it is necessary to find substitutes of them or to develop producing techniques in order to manufacture UHSFRC economically. In this study, we investigated if it was possible to substitute blast-furnace slag instead of silica fume and steel fiber of home manufacture instead of one of overseas manufacture.

• Journal of the Korean Ceramic Society
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• v.36 no.6
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• pp.625-631
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• 1999

Ceramic tapes were fabricated by ultrasonically spraying slurries of monodispersed spherical and alumina powders. Effects of slurry compositions on tape forming were investigated. A relatively fast rate of solvent evaporation caused pores and cracks to be formed. A good chemical affinity between solvent and binder gave rise to binder separation resulting in inhomogeneous distribution of binder. Defect-free silica tapes with uniform distribution of particle packing and the binder were obtained from the solvent having a low chemical affinity and a slow evaporation rate and containing appropriate amounts of the binder and the plasticizer. Tape thickness could be controlled by adjusting solids loadings and slurry feed rates. It was possible to fabricate a tape in 15 $\mu\textrm{m}$ thickness from 7 vol% alumina slurry.

• Journal of the Korean Ceramic Society
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• v.31 no.12
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• pp.1507-1512
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• 1994

High strength cement hardened body was prepared by ordinary portland cement, silica-fume, super-plasticizer and the industrial by-product powder such as tailing, paper sludge ash and granulated slag. These raw materials were mixed and formed with w/c=0.18. The cement hardened body is cured in the autoclave at 18$0^{\circ}C$, 10atm. These admixtures made the compressive strength of all specimens develope by 170~230%. The highest compressive strength could be obtained by 236 MPa when mix composition was 14 wt% of silica-fume and 26 wt% of granulated slag. The compressive strength increased with decreasing the average pore size and the amount of the poe over the size of 50 nm by which the appearance of high compressive strength of the cement hardened body were mainly influenced. In the result, the hydration products were C-S-H, tobermorite and ettringite and it was realized that the reason why the cement hardened body became dense and revealed the higher strength was that those hydrates were formed inside of the pore and filled in it and the unhydrated materials played the role of an inner-filler.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.898-901
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• 2006

To fabricate mono layer green sheet (MLGS) of transparent dielectric for PDP front panel, dispersion of transparent dielectric slurry and various properties of green sheets were examined as a function of amount and kinds of organic additives. Sedimentation height and viscosity of slurry were measured to determine proper types and amount of dispersant in non-aqueous system transparent dielectric slurry. Many MLGS having various ratios of the transparent dielectric glass frit, binder and plasticizer were fabricated. Finally we got the transparent dielectric layer of high transparency and free from residual pore might be remained in the gap between the electrodes.