• Research in Plant Disease
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• v.12 no.1
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• pp.20-24
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• 2006

Several pathogens associated with bulb rot of lilies in storage house were identified with respect to rot types. Rot patterns were grouped into four different types; brown rot of bottoms, brown rot of shoots, water-soaked rot and blue mold. Brown rot of bottoms was the highest in frequency with 72.5%, and brown rot of shoots the least with 23.0%. Dominant pathogens were differed with rot patterns, brown rot of bottoms by Fusarium oxysporum, blue mold and brown rot of shoots by Penicillium brevicompactum and P. fellutanum. In wound-inoculation tests, Penicillium and Fusarium isolates caused severe rot on the bulbs. Bulb disinfection before storage by captan showed the most prominent control value of 95.2% followed by thiophanate-methyl with 85.6%.

• Polymer(Korea)
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• v.30 no.5
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• pp.412-416
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• 2006

The superparamagnetic nanoparticles were prepared by coprecipitation of $FeCl_3$ and $Na_2SO_3$ with $NH_4OH$ and the surface charge on hydroxyl group by chemisorption was changed depending on pH. We studied correlation between surface charge of magnetite and pH. Using this correlation the properties of poly (acrylic acid) (PAAc) hydrogel embedded with magnetite was studied. The magnetite was characterized by XRD, AFM. and FTIR. The zeta-potential of magnetite was influenced by pH: great positive charge was shown high under the pH 4 and isoelectric point was found at pH 7. The hydrogen bond formed by combining oi PAAc hydrogel and magnetic colloid under pH 4 caused tensile strength to increase, while swelling and elongation at break to decrease. The result confirmed that the magnetic moment was increased proportionally to the content of magnetite.

• Journal of Adhesion and Interface
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• v.8 no.3
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• pp.9-15
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• 2007

The interfacial evaluation of surface modified Jute fiber/polypropylene (PP) composites before and after hydration was investigated using micromechanical test and dynamic contact angle measurement. The IFSS of alkaline and silane-treated Jute fiber/PP composites increased, whereas after hydration, the IFSS of the untreated, alkaline- and silane-treated Jute fibers/PP composites decreased due to swelled fibrils by water infiltration. The interfacial adhesion of silane treated fiber/PP composites was higher than alkaline-treated or the untreated cases. The surface energies of Jute fiber treated under various conditions were obtained using dynamic contact angle measurement. Especially after hydration, the thermodynamic work of adhesion was calculated by considering water interlayer, which indicated the stability of IFSS between silane treated Jute fiber and PP matrix showing better than others.

• Journal of the Korea Concrete Institute
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• v.28 no.6
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• pp.665-672
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• 2016

This study is conducted to investigate the effect of phase change materials (PCM) on hydration heat and strength characteristics of cement mortar. Two types of Barium and Strontium-based PCMs were used in this study and the addition ratio of each PCM to the cement mortar ranged from 1% to 5% by cement weight. Flow test, semi-adiabatic temperature rise test, compressive strength and flexural strength test were carried out to examine the PCM effect on heat and mechanical properties of cement mortar. Test results indicated that PCMs used in this study were effective to control hydration heat of cement mortar, and Barium-based PCM slightly reduce flow value. The compressive and flexural strength of cement mortar with PCM decreased with increasing the adding mount of PCM. The prediction model for compressive strength of cement mortar with different addition levels of PCMs are suggested in this study.

• Resources Recycling
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• v.3 no.3
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• pp.27-31
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• 1994

We tested the limestone sludge produced in Pohang Iron & Steel Co., Ltd. as a filler powder for the effective use of portland cement. Hydration process was investigated by measuring the hydration rate, the amounts of non-evaporable water and compressive strength of cement-limestone sludge paste prepared by mixing limes-tone sludge with cement. The results obtained in this study can be summarized as follows: 1. There is no significant difference between the cases of adding up to 10% limestone sludge and those of unmixed cement system. However the reaction rate increases in the 5% limestone sludge system(due to the effects of fine). 2. The compressive strength increases proportionally with increasing the measured amount of non-evaporable water, Adding 5% limestone sludge also increases the strength a little higher, and the compressive strength and calcium silicate hydrates. In the case of the mixed limestone sludge, $2\theta$=$11.7^{\circ}$ peak appears in the samples of 28 days hydration. This peak indicted the presence of calcium carboaluminate hydrate. Although limestone sludge is generally regarded as a inert materials, some kinds of cement can produce a calcium carboaluminate by reacting with aluminate in cement pastes.

• Applied Chemistry for Engineering
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• v.3 no.3
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• pp.507-515
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• 1992

This study was carried out to investigate the heat-storage/-release characteristics of the thermochemical reaction of the calcined dolomite and steam system for the application of regenerative heat exchangers with the packed bed shape experimental apparatus. The experimental data were obtained at the following conditions ; the hydration temperature was $150-400^{\circ}C$, the dehydration temperature was $700-800^{\circ}C$ and the steam mass flow rates were 294, 430 and 567 g/hr. In the present study, it was found that MgO of the calcined dolomite was not hydrated during the hydration process under the studied experimental conditions. Therefore, MgO of the calcined dolomite can be regard as an inert material. Because the reaction was proceeded from the packed bed input to packed bed output and from wall to center, it could be thought that the rate determining step is not the reaction itself but the heat transfer.

• Resources Recycling
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• v.28 no.1
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• pp.32-39
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• 2019

The present study investigated hydration of alkali activated slag incorporating sulfate as a form of anhydrite by employing thermodynamic modeling using the Gibbs free energy minimization approach. Various parameters were evaluated in the thermodynamic calculations, such as presence of sulfide, precipitation/dissolution of AFt/AFm phase, and the effect of oxic condition on the predicted reaction. The calculations suggested no significant difference in the void volume and chemical shrinkage, which might influence the performance of the mixtures, in spite of various changes of the parameters. Although the types of hydration products and their amount varied according to the input conditions, their variations were smaller range than that induced by water-to-binder ratio. Moreover, it did not affect the amount of C-(N-)A-S-H which was the most important hydration product.

• Magazine of the Korea Concrete Institute
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• v.7 no.3
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• pp.137-148
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• 1995

In this study, a program for evaluation of heat transfer and thermal stress of mass concrete is developed and verified by 2-experiments (internally and externally restricted). Furthermore, the result of the program is compared with those of ADINA-T and ADINA. As a result of the comparison, the proposed method produces comparable results with those from the popular programs (ADIIVA-T and ADINA) and shows the usefulness of the developed program for the evaluation of thermal stresses of mass concrete in both internally and externally restricted structures.

• Analytical Science and Technology
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• v.28 no.2
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• pp.106-111
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• 2015

Changes in antimicrobial peptide-lipid mixtures were investigated using ³¹P solid-state nuclear magnetic resonance spectroscopy. An antimicrobial peptide, protegrin-1, and phosphatidylcholine were deposited on a thin cover glass and incubated under a relative humidity of 95%. The changes in the mixtures were observed after hydration or air-drying. How repetitive hydration and drying changed the phase of the sample was also observed. The degrees of disruption of the well-aligned bilayers of phosphatidylcholine were determined quantitatively by simulating the experimental spectra. The peptide-lipid mixtures changed reversibly after hydration and drying, and the samples reached an equilibrium state after several repetitions.

• Analytical Science and Technology
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• v.13 no.3
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• pp.338-345
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• 2000

The intercalated compounds of alkylsulfonate into hydrated and dehydrated zinc were synthesized. From the XRD, FT-IR, TGA, elemental analysis data, and the molecular size, the orientation of the intercalated alkylsulfonates was determined. For the hydrated compounds, alkylsulfonates were intercalated into hexaqua zinc layer with the bilayer structure of $32.9^{\circ}$ angle of inclination. For the dehydrated compounds, alkylsulfonates were directly bonded to zinc ion with the bilayer structure of $51.4^{\circ}$ angle of inclination.