• Journal of the Korean housing association
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• v.22 no.6
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• pp.61-69
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• 2011

Korea's traditional house type, the Hanok, has been the essence of Korean domestic culture for hundreds of years. However, Hanok, have begun to disappear as result of urbanization. Because mud walls are crude and weak in water walls are also easily broken by impact. There are further problems in that construction cost is expensive and takes more time than modern house construction, and that the maintenance of Hanok is more difficult than people sometimes predict. Despite much interest in Hanok construction, there is a lack of in younger generation. Thus seeking new ways of maintaining Korea's traditional housing culture and extending Korean traditional houses is important. This study proposes directions for creating new residential environments for the future generation of Korea. A Dry-wall alternative to the Korean traditional mud wall is particularly needed. Dry-walling, made by sustainable materials such as mud board and wood, can strengthen the advantages and make up for the weaknesses of the Korea traditional mud wall. In this study, both wall types underwent various evaluations in terms of their performance in insulation testing, freezing and thawing testing, impacting testing and weight measuring (the size of material in this experiment was $69cm{\times}105cm$). On all of these tests, findings revealed that the dry-wall alternative performed better than traditional mud wall.

• Journal of the Korea Institute of Building Construction
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• v.5 no.4 s.18
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• pp.115-120
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• 2005

In recent years, polymer-modified mortars using polymer dispersions have been widely used as finish and repair materials in the construction industry because of their excellent properties compares to those of ordinary cement mortar. Especially, the adhesion improvement of ordinary cement mortar and concrete has attracted a great deal of attention from researchers, and several unique and simply applicable techniques for the adhesion improvement have been developed. The purpose of this study is to evaluate the abrasion resistance of polymer-modified mortar according various curing methods. The polymer-modified mortar are prepared with various polymer-cement ratios, and are subjected to three curing methods such as dry rure, standard cure and freezing and thawing cure after two curing methods, and then tested for abrasion. From the test results, the polymer-modified mortars with various polymer-cement ratios have some superior abrasion resistance compared with plain mortar. The abrasion resistance of polymer-modified mortars increase with an increase in the polymer-cement ratio, and is better under water cure than any other curing methods. It is concluded that the abrasion resistance of cement mortar is markedly improved by modifying of polymer dispersion.

• Journal of the Korea Institute of Building Construction
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• v.7 no.4
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• pp.117-124
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• 2007

Focused on the material-related aspect for enhancing the durability of concrete, the present study analyzed the effect of glycol ether admixture, which is a chemical admixture that can compact the structure of concrete by entraining air inside the concrete, on the basic physical properties and durability characteristic of the concrete. In analyzing the results of experiment, we examined the basic physical properties and durability characteristic of concrete according to addition rate based on OPC and selected the optimal addition rate. In addition, with the optimal addition rate, we added glycol ether admixture to concrete, which contained fly ash used as binder and high-performance water reducing agent for reducing the unit quantity, and examined changes in the characteristics of the concrete. According to the result, the optimal addition rate of glycol ether admixture was 3% of the unit quantity of cement, and the addition of binder and chemical admixture did not have a significant effect on unhardened concrete but reduced the air content. In addition, concrete showed resistance performance of around 30% to carbonation and around 40% to drying shrinkage. In addition, as for resistance to freezing and thawing, the relative dynamic modulus of elasticity was over around 85% through atmospheric curing. These performances prove the effect.

• Applied Chemistry for Engineering
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• v.5 no.5
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• pp.786-794
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• 1994

The strength and durability of polymer-cement mortars were investigated. The specimens of polymer-cement mortar were prepared by using styrene-butadiene rubber(SBR) latex, ethylene-vinyl acetate(EVA) emulsion and polyacrylic ester(PAE) emulsion with various polymer-cement ratios(5, 10, 15, 20wt%). For the evaluation of durability of polymer-cement mortars, freezing-thawing, acid resistance and heat resistance tests were conducted. With an increase of polymer-cement ratio, the frost resistance of polymer-cement mortars was greatly improved, but acid and heat resistance were deteriorated. The compressive and flexural strengths of SBR polymer-cement mortars were improved with an increase of polymer-cement ratio, whereas those of EVA and PAE polymer-cement mortars reached maximum value at polymer-cement ratio of 10wt%.

• Journal of Embryo Transfer
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• v.19 no.1
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• pp.27-34
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• 2004

This study evaluated the efficiency and compared with different materials of loading vessels for vitrification-plastic/glass, copper grid and nylon. The loading method, vitrification, cryop-reservation and warming method of the oocytes were examined. The loading samples prepared in manual or company-made and sterilized, loaded the COCs selected on each samples and cultured for maturation during 40 hours, and then exposed sequentially to ethylene glycol solution. Thawing method was reversely treated and exposed for warmed oocytes. After oocytes were thawed, fertilized and cultured in vitro for 3-4 hours, rates of development and morphological appearance were examined. The results were as summarized: ㆍOPS from company-made or hand-made of the hematocrit micropipettes, NLS from fishing line and EMG from company-made for EM were used for loading oocytes, respectively. ㆍThe efficiency of freezing method and loading convenience were orderly higher in OPS, NLS and EMG. The optimal capacity per vessel was orderly lowered in NLS, EMG and OPS, respectively. ㆍAfter oocytes were warmed, the recovery rate, morphology and rate of development were orderly higher in OPS, NLS and EMG, respectively. ㆍIn conclusion, OPS has the advantages of achieving a little more survival and preserving results than other two loading methods.

• Korean Journal of Pharmacognosy
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• v.38 no.2 s.149
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• pp.117-122
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• 2007

The specific activation of the immune system to control cancer growth in vivo has been a long-standing goal in cancer immunology. Whole tumor Iysates have been used either alone or combined with adjuvants to induce specific immune response in vivo. Here, we examined whether freezing/thawing (F/T) colon26-M3.1 tumor cell admixed with EN-3, glycoprotein purified from Acanthopanx Senticosus, could stimulate in vivo immunity by using a murine experimental tumor metastasis model produced by colon26-M3.1 carcinoma cells. Vaccination of mice with F/T treated colon26-M3.1 carcinoma cells in combination with EN-3 as an adjuvant resulted in a significant inhibition in tumor metastasis of mice against live colon26-M3.1 carcinoma challenge. In addition, the splenocytes from vaccinated mice exhibited a higher proliferating activity and secreted interferon-${\gamma}$. These results suggest that EN-3 can be applied to immunoadjuvant to enhance the antitumor immunity in vivo.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.1029-1034
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• 2001

The purpose of this research is to develop rapid setting cement latex modified concrete (RSLMC) which will be used to overlay bridge deck for maintaining and repairing. The main experimental variables were the types of rapid setting cement and variation of latex and antifoam agent contents were selected as admixture factor, then the properties of workability and strength development and durability properties were investigated. The results of this study show that latex content give increment of a slump due to surface tension in polymer particles and reduce unit weight of water for preservation of workability. In addition, When no and 1.6~3.2% antifoam agent were mixed, 8%, 2.0~3.8% were respectively obtained. An increasing the amount of latex produced concrete with increased flexural strength, but with slightly lower compressive strength. Rapid chloride permeability and freezing-thawing test carried out. As a results, according to increment of containing ratio antifoamer, strength of RSLMC increase, permeability showed lower value than ignorable 100 coulombs. Also, in the case of more than antifoamer 1.6%, the relativity dynamic modulus is mantained more than 90%, but in case of 0, 5%, it decrease. In consequence, with the view of strength and workability of RSLMC, it is considered that appropriate content ratio of antifoam agent and latex solid are respectively 1.6% by latex weight, 15% by cement weight.

• Journal of the Korean Society for Advanced Composite Structures
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• v.6 no.3
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• pp.41-49
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• 2015

The repair of manhole raise has been caused much construction times and disruption of traffic flow, serious environmental pollution from crushed construction wastes, and budget waste due to the repeated repair construction works. In order to overcome such problems, we have developed the new manhole repairing composite structures by using a glass fiber-reinforced polymer (GFRP) pipe, which can raise manhole to the regular height of the overlayed road pavement with rapid construction and minimum traffic jams. This environmental-friendly technology is method completed by the methyl methacrylate monomer (MMA) double wide flanged GFRP pipe composite structures in order to raise manhole to the regular height. In this paper, two kinds of the compressive strength tests of MMA mortar composites were conducted and evaluated by a general compressive strength test, and compressive strength test after freezing-thawing resistance test. It was found that this MMA mortar composites will be used for the application of the double wide flanged GFRP pipe composite structures.

• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.2
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• pp.3778-3783
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• 1975

The objective of this study is to determine an appropriate cement of soil-cement in which silty soil of salty tidal flat with low plasticity was used. Physical, chemical and mechanical tests were conducted to find out the standard properties of the soil to be used. Various cement contents used in this test were 8%, 10%, 12%, and 14%, and the compressive strength was tested after 7 days and 28 days of standard curing in the above each cement content respectively. The results obtaind are summarized as follows. 1. As the cement content was increased from 8% to 14%, Maximum dry density (M.D.D.) and optimum moisture content (O.M.C.) were not changed remarkably. 2. Density of soil-cement was directly proportional to cement content and inversely proportional to water content. 3. OMC was generally decreased in proportion to the increase of cement content. 4. Compressive stranth was directly proportional to centent and inversely proportional to water content. 5. In freezing and thawing test, maximum loss of 10% in the total Weight was found on the 8% cement mixture. and This loss was rapidly decreased to 2% when the Cement content of the mixture was more than 10%.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.5
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• pp.23-30
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• 2007

This research was to evaluate the shrinkage and durability performance of latex modified repair mortar and to improve the service lift of the agricultural concrete structures. The shrinkage characteristics of the repair material creates the delamination of repair materials and existing concrete. It may reduce the service life of structures. Also the reduction of durability performance of the repair materials induces the destruction of the repaired concrete structures at early stage. In this research, plastic and drying shrinkage, thermal expansion coefficient for shrinkage properties, durability performance, permeability, repeated freezing and thawing, and resistance of chemical solution test were performed. Test results showed that the latex modified repair mortar indicated the shrinkage amount which the delamination does not happen, and the latex modified repair mortar appeared excellent long-term durability performance which can increase the service life.