• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.359-360
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• 2009

This Study is performed Mock-up test accounting for height of placement to review behavior of mass concrete according to kinds of cement & form. First, we measured hydration heat and show a different hydration heat generation characteristics as compared with each other. And we measured mortar outflow, the strength of concrete core and standard specimens, concrete's ability to resist chloride ion penetration in order to durability estimation of concrete. This study was aims to improve quality of mass concrete under marine environment.

• The Korean Journal of Pesticide Science
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• v.8 no.4
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• pp.272-279
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• 2004

The process for the preparation of fungicide propineb starting with 1,2-diaminopropane was studied on the optimal condition base. Side reaction producing toxic material 1,2-propylenethiourea could be ieduced effectively by using phase transfer catalyst and the product was noticed to show a great improvement in yield and purity. Especially when the phase transfer catalyst tetraphenylphosphonium bromide is used, the yield and the purity of the product were found to be best with up to 95 and 96% respectively and the byproduct content was shown within 1.7%. Also, the contents of wetting agent AES and dispersing agent APS were optimally chosen $3.1\sim4.0%$ and $4.0%\sim5.0%$ respectively for the improvement of suspensibility and wettability of Propineb WP.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.257-258
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• 2009

This study is about the correlation between KS F 2711 and NT Build 492, and about the effectof hydration accelerating admixture. For this study, various types of binder are tested.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.06a
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• pp.150-151
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• 2009

수화성이 회복된 미분말에 시멘트를 10% 첨가하고 무수규산을 20 wt% 배합하여 제작한고화체가 방사성 고화체 압축강도 인수기준에 만족함과 동시에 부피증가를 최소로 할 수 있었고이 조건으로 ANS 16.1 방법에 준하여 고화체 침출 실험이 진행 중에 있다. 고화체의 압축강도 및 침출지수 모두 처분장 인수 기준에 만족할 경우 콘크리트 미분말 폐기물의 부피 증가를 최소화함은 물론 안정한 상태로 처분할 수 있을 것으로 예상된다.

• Polymer(Korea)
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• v.27 no.4
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• pp.349-357
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• 2003

Hydrogels for wound dressing from a mixture of poly(vinyl alcohol) (PVAL), poly(N-vinyl pyrrolidone) (PVP), hexylene glycol (HG) and chitosan were made. The hydrogels were obtained by physical crosslinking of freezing and thawing, chemical crosslinking of irradiation, and irradiation after freezing and thawing of mixture solutions. The solid concentration of PVAL/PVP/HG/chitosan was 15 wt%. The concentration of chitosan was 0.3 wt%, and the ratio of PVAL/PVP was 6:4. The concentration of HG was in the range of 1∼5 wt%. The number of repeated freezing and thawing was in the range of 1∼3 times, and gamma irradiation doses were 25, 35 and 50 kGy. The physical properties such as gelation, water absorption and gel strength of hydrogels were examined. Gel content and gel strength decreased as HG concentration increased, whereas degree of swelling increased. Gel content and gel strength increased as irradiation dose and the number of freezing and thawing increased, whereas degree of swelling decreased. The hydrogels were evaluated for the healing effect for animals and for the antibacterial effect.

• Polymer(Korea)
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• v.32 no.5
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• pp.421-426
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• 2008

pH-responsive P(MAA-co-EGMA) hydrogel microparticles were synthesized via dispersion photo polymerization and the feasibility of the particles as the cosmetic formulation was investigated. Rh-B and the functional materials for the cosmetic application such as ascorbic acid, adenosine, EGCG, and arbutin were loaded in the P (MAA-co-EGMA) hydrogel microparticles in order to examine the interaction between the hydrogel and the loaded materials. In the loading experiments, Rh-B showed the highest loading efficiency to the P(MAA-co-EGMA) hydrogels due to the electrostatic attraction between the negative charge of the hydrogels and the positive charge of Rh-B at the ionized states. However, the functional materials showed relatively low loading efficiencies because of the electrostatic repulsions between the negative charges of both the hydrogels and the materials at the ionized states. In addition, P(MAA-co-EGMA) hydrogel microparticles showed pH-responsive release behavior of Rh-B according to the external pH changes.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.5
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• pp.17-25
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• 2010

We studied on the watertightness improvement of cementitious material for durability enhancement of concrete. For improvement of watertightness of OPC and OPC with fly ash, we used various materials with watertightness properties to OPC and OPC with fly ash. The performance of watertightness improvement of cementitious materials closely related to formation of CSH by pozzolanic reaction and to reducing of size of contact angle in cement pore by using organic fatty acid. And volume of CSH formation at early hydration have an influence of watertightness improvement and reduction of long-term water absorption rate. In using of fly ash, improvement of workability by using the spherical fly ash caused to densify on the structures of cement material and CSH formation by pozzolanic reaction and cement using fly ash also caused watertightness improvement of cementitious materials. For improvement of concrete durability by watertightness, cementitious materials need using watertightness materials and at using fly ash, also it have to the effect of improvement of watertightness of cementitious materials by pozzolanic reaction.

• Journal of the Korea Institute of Building Construction
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• v.12 no.4
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• pp.369-376
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• 2012

In this study, to reduce the hydration heat velocity (HHV) of high-strength mass concrete at early ages, phase change materials (PCM) that could absorb hydration heat were applied, and the changes in autogenous shrinkage were investigated, as well as the relationship between the hydration temperature and autogenous shrinkage. The acceleration of the cement hydration process by the PCM leads to an early setting and a higher development of the compressive strength and elastic modulus of concrete at very early ages. The function of PCM could be worked below the original melting point due to the eutectic effect, while the hydration temperature and HHV of high-strength mass concrete can be decreased through the use of the PCM. A close relationship was found between the hydration temperature and autogenous shrinkage: the higher the HHV, the greater the ultimate autogenous shrinkage.

• Research in Plant Disease
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• v.9 no.4
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• pp.205-208
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• 2003

Fungicides of tebuconazole wp, iprodione wp and flusilazole wp were applied for the control of postharvest fruit rots of kiwifruit (Actinidia deliciosa) in the field in 2000 and 2001. More than 3 consecutive applications of these fungicides from the late June with 10-day-interval successfully controlled the diseases. It was found in the field trial in 2002 that 4 consecutive spays from mid of June with 10-day-interval was found to be the most effective application program for tebuconazole wp, iprodione wp and flusilazole wp, The results suggested that currently registered fungicides of benomyl wp and thiophanate-methyl wp can be substituted by tebuconazole wp, iprodione wp and flusilazole wp for the control of the diseases in Korea. Use of these fungicides can restrain emergence of fungicide resistant strains of postharvest fruit rot pathogens with benefit of reduced application of chemicals for food safety and environmental conservation.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.645-648
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• 2008

In this study, to evaluate the correlation between hydration heat and autogenous shrinkage of high strength concrete in early age, statistical method present numerically hydration heat and autogenous shrinkage was studied. First of all, hydration heating velocity and autogenous shrinking velocity as quantitative coefficients which represent the main properties of hydration heat and autogenous shrinkage were proposed. Two coefficients were calculated by statistical analysis and were equal with the regression coefficient. To verify the validity of the proposed statistical analysis method, data of hydration heat and autogenous shrinkage gathered by a real experiment were analyzed by it. In results, properties of hydration heat and autogenous shrinkage of high strength concrete in early age were analyzed quantitatively. Also evaluation and comparison of the correlation between hydration heat and autogenous shrinkage with numerical value were possible.