• 펄프종이기술
• /
• 제37권1호
• /
• pp.10-16
• /
• 2005

Flocculation of fibers and its distribution in paper are related to flocculation mechanisms, retention and drainage. Relationship between flocculation mechanisms and physical properties of paper has not been fully studied. In this study, flocculation of fibers was investigated by changing cationic polymers for flocculation mechanism analysis. Flocculation of stock and physical strength of paper were similar when using branched PAM and linear PAM with fillers and microparticles Flocculation and physical strength were also similar when using branched PAM and linear PAM and microparticles without fillers. In that case excessive flocculation was not produced, so formation was improved but physical strength was decreased. When using branched PAM instead of linear PAM with filler addition, drainage time was decreased, air permeability was improved, and physical strength was increased.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2001년도 춘계학술대회 논문집
• /
• pp.44-51
• /
• 2001

To account for uncertainties involved in an economic analysis of project, sensitivity analysis are usually being done in Korea. Though useful for policy analysis, but it larks explicit consideration of probability of occurring certain events considered in the sensitivity analysis. Risk analysis otherwise can explicitly account for the probability of certain event which has dire impact on project viability, such as cost, discount rate, and size of benefit. This paper reports experience of applying risk analysis method for economic evaluation of railroad investment. Probability distribution of event has paramount impact on the risk analysis results, while not many prior researches dealt with these issues. Probability distribution of rolling stock cost and operating cost, in addition to those cost variables, are developed considering railway demand in this study. Case study results are reported. Issues in applying risk analysis are reported in addition to further research direction.

• 한국세라믹학회지
• /
• 제30권12호
• /
• pp.1023-1028
• /
• 1993

To obtain a single phase of Ba2Ti9O20 at lower temperature than previious other researches. We investigated the effect of Zr substitution for predetermined portions of Ti in Ba2Ti9O20. In this study, the four compounds(x=0, 0.028, 0.048, 0.068) of Ba2(Ti1-xZrx)9O20 were prepared by coprecipitation reaction of BaCl2, TiCl4 and ZrOCl2 with (NH4)2CO3 and NH4OH as the coprecipitating agents and pH regulators, in queous solution. Owing to 4.8 mol% addition, the single phase of Ba2Ti9O20 showing high Q was obtained at 115$0^{\circ}C$ which is lower by 25$0^{\circ}C$ than the temperature in case of mechanical mixtures of BaCO3 and TiO2.

• 한국세라믹학회지
• /
• 제30권8호
• /
• pp.671-677
• /
• 1993

Effects of PbTiO3 addition on dielectric properties and extent of PbO loss in Nd-doped Pb(Mg1/3Nb2/3)O3 system were investigated. As the proportion of dopping increased, the phase transition temperature shifted to low region, and the dielectric constant at room temperature decreased rapidly. But as the proportion of PbTiO3 increased, the phase transition temperature shifted to high retion, and the dielectric constant at room temperature increased. The substitution of Nd3+ for Pb2+ decreased the amount of PbO evaporation, therefore the sample sintered well in case of only 1 mole% adding excess PbO.

• 한국세라믹학회지
• /
• 제13권4호
• /
• pp.25-35
• /
• 1976

Mullite was synthesized by using kaolin and $\alpha$-alumina, and halloysite and aluminum hydroxide as raw materials at the various temperature in the range of 1200$^{\circ}$-1750$^{\circ}$C. The degree of mullitization was measured respectively by a quantitative X-ray diffraction method and a chemical analysis method. The rate and the maximum degree of mullitization were found to increase with temperature . The reaction completed at 1600$^{\circ}$Cfor less than 30 minutes, and yielded 98% mulllite inpurity in the case of kaolin-Al(OH)3. TiO$_2$ up to 3% was added to the batches of kaolin-Al(OH)$_3$. the effect of addition on the mullitization was investigated and found to decrease the sintering temperature for the mullitization. The mechanism of TiO$_2$ addition on the formation of mullite was also discussed.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2005년도 추계학술대회 논문집
• /
• pp.282-286
• /
• 2005

Contents of these treatise propose method to embody station addition and passivity point correction. That store in TCMS's memory being downloaded all train running path data that is consisted of name of station and station code, departure station, destination station, train number, running time through PCMCIA memory card. Search relevant running path data and current station, destination station, the next station start time present to TCMS's display. In case it is no received information of station, device that do function of passenger broadcasting and pilot light does not act. This time, if input information of current station, relevant device does point revision.

• 한국전기전자재료학회논문지
• /
• 제13권5호
• /
• pp.420-425
• /
• 2000

Crosslinked polyethlyene/silane crosslinked polyethylene(XLPE/SXLPE) blends were prepared by a twin screw extruder and their water tree growing electrical breakdown and crossinking characteristics were investigated. The water tree characteristics of XLPE were improved by the addition of SXLPE when samples were crosslinked only by the thermorolysis of DCP (dicumyl peroxide). However steam curing process was not good for water tree characteristics. It was also found that the rate of water tree growing of XLPE/SXLPE blend increased when the content of SXLPE was 50%. AC breadown strength slightly increaed by the addition of SXLPE to XLPE when samples were crosslinked only by the thermorolysis of DCP. It was also found that the degree of crosslinking of XLPE/SXLPE blends were higher than that of XLPE in the case of the content without steam crosslinking process.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1997년도 추계학술대회 논문집
• /
• pp.405-408
• /
• 1997

The microwave dielectric properties of CuO and CdO addition of BiNbO$_4$ceramics were investigated. As the content of CdO increased, sintered density and quality factor is decreased. With increase in sintering temperature, the dielectric constant and quality factor is increased. In case of specimen sintered at 96$0^{\circ}C$ with 0.03 wt% CuO and CdO, the microwave dielectric properties obtained were dielectric constant of 41.2, quality factor (Q$\times$f) of 6, 500, temperature coefficient of resonant frequency of ppm/$^{\circ}C$.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 춘계학술대회 논문집 유기절연재료 방전 플라즈마
• /
• pp.33-36
• /
• 2000

Electrical properties of Crosslinked polyethylene/silane crosslinked polyethylene (XLPE/SXLPE) blends were studied. Silane coupling agents of various contents were added to blends and their water tree and electrical breakdown characteristics were investigated. The water tree length of XLPE/SXLPE were increased by the addition of silane coupling agents except the case of SXLPE 10 % containing coupling agents of 0.5, 1.0 phr. AC breadown strength slightly increased by the addition of coupling agents to XLPE/SXLPE blends in cases of SXLPE 20 % containing coupling agents of 2.0 phr and SXLPE 50 %. The tendency of effects on water tree and breakdown characteristics was inverse.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 하계학술대회 논문집
• /
• pp.270-273
• /
• 2000

For the well-preparation of the superconducting wire by electrophoresis, the control of the cracking on the YBCO, BSCCO superconductor deposited on Ag wire in acetone and buthanol solution with PEG(poly-ethylenglycol) was investigated with XRD and SEM analysis. After deposition, drying and heat treatment process, the cracks on the deposited surface of YBCO and BSCCO samples was clearly removed and decreased, which was perpared in suspension with addition of PEG from 1 to 3ml. However, in the case of the addition rate of PEG in acetone suspension was exceeded in 3ml, BSCCO superconductor deposited on Ag wire was slightly melted at 90$0^{\circ}C$ which was the same heat treatment condition of other samples with different additin rate of PEG. In the process of electrophoretic deposition, drying and heat treatment, PEG added into the suspension solution as a binder was very useful to prepare the crack-free thick film-wire of YBCO and BSCCO.