• Structural Engineering and Mechanics
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• 제84권1호
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• pp.49-61
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• 2022

This paper presents an experimental investigation into the effectiveness of using carbon fibre reinforced polymer (CFRP) and steel plates to repair damaged reinforced concrete (RC) beams with circular web openings at shear zones. It highlights the effectiveness of externally bonded CFRP and steel plates in repairing damaged RC beams by analysing the repaired beams'load capacity, deflection, strain, and failure mode. For the experiment, a total of five beams were used, with one solid beam as a control beam and the other four beams having an opening near the shear zone. Two beams with openings were repaired using inclined and vertical configuration CFRP plates, and the other two were repaired using inclined and vertical configuration steel plates. The results confirm the effectiveness of CFRP and steel plates for repairing damaged RC beams with circular openings. The CFRP and steel plates significantly increase ultimate capacity and reduce deflection under the openings. The inclined configuration of both CFRP and steel plates was more effective than the vertical configuration. Using an inclined configuration not only increases the ultimate capacity of the beams but also changes the mode of failure from shear to flexural.

• 한국지반공학회논문집
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• 제19권6호
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• pp.325-334
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• 2003

댐체 코어부에 발생한 수압파쇄와 이로 인한 유로의 발달 및 누수량 증대 등의 문제점을 구조적으로 차단하여 댐의 안정성을 확보하고, 장기적으로 댐을 유지관리 운영하는 데에 문제점이 없도록 댐 코어부를 보수.보강한다는 것은 쉬운 일이 아니다. 본 연구에서는 손상된 흙댐 코어의 보수.보강을 위한 CGS 공법(Compaction Grouting System)의 적용성을 천공과 주입과정에 대한 고찰과 그 결과에 대하여 검토하고, 현장에서의 계측치와 FEM 해석 결과의 비교.검토를 통하여 확인하였다. 현장 계측 결과, 공정이 진행되면서 선단 압력은 증가하고 주입량은 감소됨에 따라 느슨한 댐 코어의 공극이 채워진 것으로 나타났으며 동일 수위에 대하여 누수량 및 탁도는 보강 후의 누수량과 탁도가 모두 감소하였으며, FEM 해석 결과 역시 보강으로 인하여 투수계수가 감소하였다. 본 연구에서 CGS 공법을 통하여 기존 댐 코어재료 특성의 변화를 최소화하면서 느슨한 공극을 채워 투수계수와 누수량을 감소시켜서 댐 코어의 차수성을 향상시킬 수 있음을 확인하였다.

• 한국의류산업학회지
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• 제10권3호
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• pp.389-393
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• 2008

The purpose of this study is to provide beauticians with the fundamental material for them to use effectively heat permanent wave and satisfy their customers. It carried out an experiment with hair of a woman in her late twenties to investigate the change of physical and morphologic characteristics by its water content when performing heat permanent wave. It evaluated the water content as 0g, 1g, 2g, 3g and 4g respectively when performing the heat permanent wave on hair, then it compared and observed the wave type, tensile strength and elongation for its physical change also observed the morphologic change by scanning electronic microscope and transmission electronic microscope. The result of experiment on the physical specificity revealed that the wave was the most ideal when the water content was 2 g. The material with much water content made wave but the result was not satisfied. In the case of hair with water content of nearly 0g didn't make wave. In terms of tensile strength and elongation, the tensile strength was generally reduced as hair was damaged, on the contrary, the elongation was increased. It observed the change of morphologic characteristic and got the result that the damage on hair cuticle was deepen as its water content was decreased. It also showed the result that damage happened on hair cuticle more than hair cortex with the observation of fine structure on hair section by transmission electronic microscope. Generally chemical treatment damaged hair. Under consideration of this aspect, the ultimate goal of this thesis is to minimize the damage of hair caused by chemical treatment and get the satisfaction on the hair style. The result of experiment presented that the hair showed the best result when its water content was 2 g.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.647-650
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• 1999

Deterioration of agricultural hydraulic structures(AHS), which are under harsh environmental conditions, is more sever than other ordinary structures. To investigate the deterioration factors of AHS, various physical and chemical analyses are performed. The porosity of AHS increases more rapidly than ordinary structures because they are subject to frequent water permeation and water-soluble materials are easily emitted to surface area. Thus, AHS are tend to be damaged by freezing and thawing more easily due to the increase of water containment inside concrete.

• 한국패션뷰티학회지
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• 제3권3호
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• pp.48-55
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• 2005

The summary of a study of efficacy of Rose essential oil and Lavender essential oil against physiologic active change s of skin caused to surfactant is as follows. 1. In feed intake efficiency, there is more significant difference than control group, and then in water intake, there are significant differences between each group. It is presented that the water intake efficiency ratio of the group treated by Rose essential oil and Lavender essential oil is higher than all of groups to be participated in experiment. And then, the reason that the group treated Lavender essential oil is lower than any other group is needed water intake to be caused by stress. 2. As the result of serum analysis, in atherosclerotic index(A.I), the cholesterol of control group is higher than that of the group treated. As HDL cholesterol is activated, the dan1aged group is higher than control group, in LDL cholesterol the control group is higher. It is seen that the damaged group of the quantity of HDL cholesterol is lower frequently in A.I. This fact is presented that HDL cholesterol that cholesterol is exhausted is changed, because of the dan1aged group that replacement is activated. 3. As the observed result of alteration of sebaceous glands, it is appeared that the demage of sebaceous glands is destroyed in the damaged group. It is observed that epidermis of the group applied by Rose essential oil after treated surfactant is dry, secretion of phenomenon of water and sebum is appeared more. It is observed that the epidermis recovery of the group applied by Lavender essential oil after treated surfactant is insufficient. And then it is seen that stratum corneum is recovered and the quantity of sebum secretion is decreased. 4. As the observed result of alteration of Mast cell group treated by Rose essential oil and Lavender essential oil for 3 weeks Luna's stain(${\times}100$), it is observed that the damaged group treated by Lavender essential oil is numerous in alteration of mast cell's number and Mast cell's size is larger than the dan1aged group. It is presented that the Mast cell's number and Mast cell's size is larger than the damaged group, the Mast cell's size and quantity of the group treated by Rose essential oil and Lavender essential oil is decreased more.

• Corrosion Science and Technology
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• 제8권4호
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• pp.153-156
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• 2009

The water cooling system for VFD (Variable Frequency Drive) of a fossil fuel power plant was reported to be shut down due to a water leak at the metal connection of the heat-sink to the hoses. In order to identify the cause of the failure, the system was visually inspected, and corrosion products were analyzed with SEM equipped with EDX. The failure was observed repeatedly at the nipples of certain location, suggesting galvanic corrosion. In a U-shaped heat sink with two nipples, for inlet and outlet, only one nipple was corrosively damaged at the tip, while the other was not. Most of the corrosion products were observed at the sound nipple and in the filter, identified as $Cu(OH)_2$. Some other corrosion products, composed of mostly $Cu_2O$, were found at the corrosively attacked nipple. A fair amount of Cl was also detected on the surface of the damaged nipple. It was concluded that galvanic corrosion was occurred due to a current leakage over the whole system, and the damage was accelerated by the accumulated chlorine ions in the cooling water.

• 한국의류학회지
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• 제34권11호
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• pp.1798-1811
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• 2010

This research evaluates the changes in the comfort-related properties of high-density fabric, such as moisture permeability and waterproofness, in order to assess the relative importance of laundry conditions for clothing properties after repeated laundering and suggest the best laundering conditions for high-density fabric through the identification of the most influential factor. A commercial high-density fabric was washed 25 times in a drum-type washer using nine different laundry conditions based on profiles derived from a fractional factorial design. To evaluate the changes in the comfort-related properties of the fabric, pore size, air permeability, water vapor transport, water repellency, and water resistance were measured. The comfort-related properties of the fabric deteriorated after repeated laundering by the damaged surface finish; in addition, the damaged surface also changed the pore size. As a result, the water repellency and water resistance decreased. The detergent was the most responsible factor to change the properties among the four factors of detergent, hardness, temperature, and RPM. The best laundering conditions for the fabric was a neutral detergent, soft water of 70ppm, a temperature of $15^{\circ}C$, and 30rpm.

• 한국식품영양과학회지
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• 제19권2호
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• pp.133-142
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• 1990

This study was attempted to compare the nutritive value of leaf with stem of the water cress Oenanthe stolonifera DC. in order to improve the eating habits and as a part of studying on the effective curing nutrients for the damaged liver. The contents of moisture crude proteinon the effective curing nutrients for the damaged liver. The contents of moisture crude protein crude fat and crude ash were 90.40% 2.85%, 0.42% and 0.74% in leaf while the contents of moisture crude protein crude fat and crude ash were 95.15% 0.77% 0.09%, and 0.64% of moisture crude protein crude fat and crude ash were 95.15% 0.77% 0.09% and 0.64% in stem respectively. The quantitative fractionation of proteini of both leaf and stem ranked albumin the highest content followed globulin prolamin and glutelin in order. It has been sh-own by SDS-polyacrylamide gel electrophoresis that water extractable protein of leaf 11 bands but those of stem were not detected. The scope of molecular weight for the main protein of water extractable protein of leaf was between 34.700 and 45,000. The amounts of extractive-nitrogen from leaf and stem of the water cress were 241.02mg% and 271.67mg% respec-tively. The amounts of free amino acid-nitrogen from the leaf and stem were 89.02mg% and 32.02mg% respectively. In free amino acid-nitrogen from the leaf and stem were 89.02mg% and 32.02mg% respectively. In free amino acid composition of both leaf and stem the major components were aspartic acid and glutamic acid. In total amino acid composition of water cress leaf aspartic and glutamic acid were the major components. Whereas alanine and thr-eonine were the major components in stem The assessment of water cress leaf and stem with chemical score. EAAl Rl showed that the values of stem were lower tendancy than those of leaf. Limiting amino acid of leaf was tryptophan while that of stem was lysine.

• 한국수자원학회논문집
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• 제52권4호
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• pp.291-300
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• 2019

상수관망시스템 내 관로가 파손될 경우, 수리를 위해 파손 관로와 인접한 밸브를 차폐하게 된다. 이때, 밸브 차폐로 인해 관망의 일부분이 고립되어 용수공급이 차단되는 단수구역이 발생하게 된다. 단수구역은 파손 관을 포함한 직접고립지역과 직접고립지역으로 인해 의도치 않게 수원으로부터 물 공급이 차단되는 간접고립지역으로 구분된다. 따라서, 관 파손에 의한 단수구역 및 단수용량은 시스템 내 설치된 밸브의 개수와 위치에 크게 영향을 받게 된다. 본 연구에서는 상수관망시스템 내 최적의 밸브위치를 결정하기 위해 최적화 모형을 개발하고 적용하였다. 예시 관망을 대상으로 단수용량 최소화를 목적함수로 설정한 단목적 최적화와 단수용량과 밸브 설치비용을 동시에 최소화하는 다목적 최적화를 각각 수행하였으며, 두 가지 모형을 통해 도출된 최적 밸브설치 결과를 비교, 분석하였다.

• 한국환경과학회지
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• 제13권1호
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• pp.11-17
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• 2004

The purpose of this study is to present the model of ecological restoration through analysis on the condition of hydrach succession process in brackish water lake. To this study, we investigate and research the present condition of brackish water lake in South Korea. Most brackish water lake in South Korea have characteristics that is come into being malignant hydrach succession. Many lakes were reclaimed to increase foodstuff production. And river conservation work seperate lakes from the ocean. In a embryological view, most lakes based on the brackish water lakes, But present lakes show many different types such as a fresh water lake, a salt lake, a brackish water lake, a swamp, and a marshland. As a result, brackish water lakes have greatly damaged by diverse artificial interventions to promote people's activities. Therefore, in order to manage brackish water lakes systematically, criteria of lake preservation must be coincide with the present conditions of hydrach succession in each lake.