• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.7-8
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• 2015

The purpose of this study is to investigate the expansion of alkali-activated geopolymer mortar containing reactive aggregate due to alkali-silica reaction. In addition, this study is particularly concerned with the behavior of these alkaline materials in the presence of reactive aggregates. The test method included expansion measurement of the mortar bar specimens and geopolymer compressive strength test. Major results that alkali-activated geopolymer mortars showed expansion due to the alkali-silica reaction. geopolymer mortars is safety for the expansion exhibited less than 0.2% at 14 day.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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• pp.31-32
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• 2003

The fixation of reactive dyes onto cotton fabrics by means of dry heat treatment was examined in terms of water regain in fabrics. Dye liquors were applied to fabrics by ink-jet printer. The fixation strongly depended on water regain. At certain level of water regain the fixation showed stepwise increase. After this point the fixation reached to saturated value. The observed results were interpreted by the aggregation behavior of dyes and reactivity of hydroxyl group of cellulose depending on the amount of the surrounding water molecules. Urea molecules played a role of water at low water regain to increase the fixation.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.318-322
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• 2004

Arsenic is a toxic and carcinogenic metalloid, whose sources in nature include mineral dissolution and volcanic eruption. Abandoned mines and hazardous waste disposal sites are another major source of arsenic contamination of soil and aquatic systems. To predict concentrations of the toxic inorganic arsenic in aqueous phase. the biogeochemical redox processes and transport behavior need to be studied together and be coupled in a reactive transport model. A new reaction module describing the fate and transport of inorganic arsenic species (As(II)), dissolved oxygen, nitrate, ferrous iron, sulfate, and dissolved organic carbon are developed and incorporated into the RT3D code.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.11
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• pp.535-543
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• 2002

Modern power grids are becoming more and more stressed with the load demands increasing continually. Therefore large stressed power systems exhibit complicated dynamic behavior when subjected to small disturbance. Especially, it is needed to analyze special conditions which make small signal stability structure varied according to operating conditions. This paper shows that the relation between small signal stability structure varied according to operating conditions. This paper shows that the relation between small signal stability and operating conditions can be identified well using node-focus point and 1:1 resonance point. Also, the weak point which limits operating range is found by the analysis of resonance condition, and it is shown that reactive power compensation may solve the problem in the weak points. The proposed method is applied to test systems, and the results illustrate its capabilities.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2009.03a
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• pp.175-176
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• 2009

Energy saving and environment-friendly dyeing method of cotton with reactive dyes is the ultra low liquor ratio dyeing because it reduces the total quantity of water, dye, salt and alkali during the dyeing process in the effluent as well as the energy consumption. However, this method may not guarantee the quality of the dyeing results due to the specs or unlevel dyeing depending upon the dyes used. The study has focused on the effect of leveling agents in the dyeing of cotton with reactive dyes under the ultra low liquor ratio (1:5). Especially Sunfix N/B MF-D which was selected for ULLR showed low-leveled dyeing comparing with the other MF-D series. A leveling agent having polycarbonate structure increased LDF values of Sunfix N/B MF-D without changing of dyeing fastness. We recommend some leveling agents to improve the leveling behavior for ULLR dyeing.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.13 no.2
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• pp.73-86
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• 2009

The problem of thermal stability of an exothermic reactive viscous fluid between two parallel walls in the plane Poiseuille and Couette flow configurations is investigated for different thermal boundary conditions. Neglecting reactant consumption, the closed-form solutions obtained from the momentum equation was inserted into the energy equation due to dissipative effect of viscosity. The resulting energy equation was analyzed for criticality using the variational method technique. The problem is characterized by two parameters: the Nusselt number(N) and the dynamic parameter($\Lambda$). We observed that the thermal and dynamical boundary conditions of the wall have led to a significant departure from known results. The influence of the variable pre-exponential factor, due to the numerical exponent m, also give further insight into the behavior of the system and the results expressed graphically and in tabular forms.

• Korean Journal of Child Studies
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• v.28 no.5
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• pp.73-89
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• 2007

The purpose of this study was to develop a reliable and valid instrument to assess Korean teachers' strategies for addressing challenging behaviors of preschoolers. The Teacher Strategy Questionnaire(TSQ) consisting of 34 items was developed with three theoretically driven factors(positive proactive, positive reactive, and negative reactive strategies). Participants were 238 preschool and daycare center teachers who responded to the TSQ. Validity and reliability of the TSQ were explored using Cronbach's $\alpha$, item analysis, and factor analyses. The reliability of the TSQ was relatively high, ranging from .74 to .85. No item needed to be eliminated. Among the three pre-structured factors of the TSQ, one positive proactive factor was identified as having two innate factors.

• Journal of the Korean Ceramic Society
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• v.32 no.9
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• pp.977-988
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• 1995

Several oxide (ZrO2, Al2TiO5, reactive Al2O3) and nonoxide (SiC, Si3N4, "ALON" (5AlN.9Al2O3)) additives were used as a microfiller for alumina based LCC (Low-Cement-Castable). High temperature prooperties (HMOR, softening under load) and the phase changes of developed LCC on various sintering temperatures were examined. In addition, thermal shock test and corrosion test were accomplished. Based on these data the effects of each microfiller on the properties of LCC were established comparing to those of the commercial LCC with amorphous silica as a microfiller. The castables, containing reactive alumina, ZrO2 and "ALON" (5AlN.9Al2O3) as a first portion, exhibited considerably higher HMOR-values over 100$0^{\circ}C$, better creep behavior, and thermal shock resistance than those of castables with amorphous silica. The LCC with 5% Al2TiO5 showed no corrosion against molten aluminum.nst molten aluminum.

• Journal of the Korean Wood Science and Technology
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• v.22 no.4
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• pp.51-60
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• 1994

Chlorodeoxycellulose derivatives have recently assumed importance since the halogen atoms can be changed with other functional groups to afford new derivatives of cellulose. Also, chlorinated cellulose has been employed as an intermediate in the preparation of various functional cellulose derivatives. In this study chlorodeoxycellulose was prepared by reaction of methylcellulose with mathanesulfonylchloride in N,N-dimethylformamide. Subsequently, conversion of the above chlorinated cellulose to unsaturated celluloseen was carried out by potassium tertiary butoxide in dimethyl sulfoxide. An anhydrocellulose as an intermediate for the reactive functional derivatives was made by simple alkali treatment. Preparation condition of allylated methylcellulose by using allylchloride and its thermal behavior were also described.

• Journal of Industrial Technology
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• v.32 no.A
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• pp.119-123
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• 2012

Diamond-like carbon(DLC) thin films with interlayer were deposited on silicon substrate using a reactive sputtering method. The thermal stability of the films was investigated by annealing the films for 1hr in air in the range of 100 to $500^{\circ}C$. The $I_D/I_G$ ratio increased with increasing temperature as related to the $sp^3-to-sp^2$transition. Accordingly, G-position shifting started from $150^{\circ}C$ in the DLC films and from $270^{\circ}C$ in the a-Si/DLC films. Moreover, in the case of the a-Si/DLC films the film still observed even after annealing at $500^{\circ}C$. The thermal stability of the reactive sputtered DLC films appeared to be improved by the a-Si interlayer.