• 감성과학
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• 제10권1호
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• pp.69-77
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• 2007

본 연구는 국내 7개 회사와 일본과 타이완 기업에서 만들어진 PET POY 사의 습열과 건축수축률을 연구하였다. 이들 사(絲)의 열적수축률들은 hank방법 (KSK 0215)과 Toray FTA-500 장치를 사용하여 측정되었으며 측정된 데이터는 측정방법에 따라 분석되고 토의되어졌다. 준비된 시료는 PET POY 85d/72f와 120d/35f이며 더구나 250d/48f와 155d/50f PET POY가 일본과 국내사 사이의 습열과 건열수축률의 비교를 위해서 역시 준비되어졌다. 그리고 각 시료들의 습열과 건열수축률들은 원사 케이크 내의 사(絲), 50,000m를 1개의 layer로 각각 나누어 각각의 layer 별로 측정되어졌으며 급내와 급간 열수축률이 측정 분석되었으며 국내와 외국 수입사(絲)에 따른 차이를 hank와 Toray 측정방법에 따라 분석하였다.

• 한국의류산업학회지
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• 제15권3호
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• pp.437-443
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• 2013

This paper investigates the physical properties of aramid and aramid/nylon hybrid air jet textured filaments for protective garments relative to ATY nozzle diameters. Three types of para-aramids(840d, 1,000d, 1,500d) and nylon(420d) filaments were prepared; in addition, 840d aramid/420d nylon and three kinds of aramid filaments were texturized with a variation of air jet nozzle diameters(0.6, 0.75, 1 and 1.2 mm) on the AIKI air jet texturing machine. The measured physical properties of 16 specimens are as follows. The linear densities of aramid and aramid/nylon hybrid ATY increased with a larger nozzle diameter. The tenacity and initial modulus of aramid and hybrid ATY linearly decreased with a larger nozzle diameter; in addition, the breaking strain increased with the nozzle diameter. The dry and wet thermal shrinkage of hybrid ATY increased with a larger nozzle diameter from 0.6 mm to 1 mm and then decreased at a nozzle diameter of 1.2 mm (which seems to be a critical diameter). The wet and dry thermal shrinkage of aramid/nylon hybrid ATY are influenced by the nylon part of the hybrid yarns because the wet and dry thermal shrinkages of aramid ATY are less than 0.2%. The instabilities of aramid and aramid/nylon hybrid ATY were not influenced by the air jet nozzle diameter; however, they increased with the linear density of ATY.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.681-684
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• 2008

순환잔골재는 천연잔골재에 비해 밀도 및 흡수율 등이 열악하여 저부가가치용으로 활용되고 있고, 사용이 한정되어 있으며, 순환잔골재를 순환골재 콘크리트는 압축강도, 인장강도 등의 강도특성이 저하하고 특히, 높은 흡수율로 인하여 수축특성이 매우 저하하는 것으로 보고되고 있다. 따라서 본 연구에서는 고속회전충격식 비중분리장치 및 원심력 미분말 집진장치 등으로 구성된 건식생산시스템을 개발하고 이를 통해 생산된 순환잔골재를 사용한 순환골재 콘크리트의 수축특성을 평가함으로서 향후 순환잔골재의 활용을 위한 기초자료를 제시하고자 한다.

• 한국의류학회지
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• 제29권9_10호
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• pp.1274-1284
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• 2005

Effect of fixation methods and relaxation treatment on the dimensional stability and physical properties of MDPPA/HMM treated cotton knitted fabrics were studied. Combination of four different fixation methods - relaxation, swelling agent treatment, pad dry cure fixation, and wet fixation - were applied to flame retardant finish of 4 kinds of cotton knitted fabric with MDPPA/HMM. Then these fabrics were washed 10 times. As a result, In swelling treatment on 10G showed relatively higher value of length shrinkage than 14G. Length and width shrinkage were increased by initial washing treatment and no further change was shown after 6 washing cycles. After 10 washing cycles, length and width shrinkage decreased. The KES standardized basic value of B/W, 2HB/W and bursting strength of interlock were relatively larger than those of single jersey. The values of B/W and 2HB/W of cotton knitted fabrics were increased by relaxation and washing treatment but were decreased by swelling treatment. In addition, the bursting strength of the cotton knitted fabrics was decreased after fusing, washing and relaxation treatment.

• 한국정밀공학회지
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• 제15권8호
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• pp.39-45
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• 1998

In the previous study. the powder casting was attempted as the rapid tooling. The powder casting was the process to cast dry powder into the casting mold transferred from R/P model and infiltrate the liquid binder to solidify the powder. And then, the melted copper was infiltrated to control the shrinkage rate of the final mold Conseqently, the shrinkage rate was under 0.1% through that process. The mechanical characteristic was also excellent. Generally, in the slurry casting, the alumina powder and the water soluble phenol were mainly used. However, the mechanical property of the phenol was not good enough to apply to molds directly. In this study, aluminium powder filled with epoxy is applicated to the slurry casting to solve these problems. The mechanical and thermal properties are better than phenol because the epoxy is the thermosetting resin. We achieved a successful result that the shrinkage rate is shortened about 0.047%. Futhermore, the manufacturing time and cost savings are significant. Finally, we assume that the developing possibility of this process is very optimistic.

• 콘크리트학회논문집
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• 제13권4호
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• pp.362-370
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• 2001

콘크리트포장 보수공사에서 조기교통개방을 위해 현재 국내에서는 초속경시멘트를 사용하고 있으나 이는 초기의 빠른 수화반응과 내.외부적 구속으로 인한 온도수축 및 건조수축이 발생하여 콘크리트포장에 인장응력을 유발한다. 구속으로 인한 수축은 콘크리트내에 균열을 발생시켜 투수성을 증가시키고 장기적으로는 내구성을 약화시킨다. 콘크리트보강재료로서 섬유는 이러한 균열을 제어하는데 효과적이다. 본 연구에서는 국내에서 사용되고 있는 3종류의 초속경시멘트의 내구성을 평가하였고 내구성을 증진시키기 위하여 콘크리트 보강 섬유를 혼입하였으며 일반 콘크리트와 섬유보강 콘크리트를 비교.분석하였다. 실험결과 조기교통개방콘크리트에서 섬유의 혼입은 일반 콘크리트보다 내구성을 증진시키는데 우수한 효과를 나타내었다.

• Advances in concrete construction
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• 제10권6호
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• pp.537-546
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• 2020

Exterior walls in buildings are exposed to various forms of thermal loads, which depend on the positions of walls. Therefore, one of the efficient methods for improving the energy competence of buildings is improving the thermal properties of insulation plaster mortar. In this study, lightweight fine aggregate (LWFA) and micro rubber ash (MRA) from recycled tires were used as partial replacements for sand. The flow ability, unit weight, compressive strength, tensile strength, thermal conductivity (K-value), drying shrinkage and microstructure scan of lightweight rubberized mortar (LWRM) were investigated. Ten mixtures of LWRM were prepared as follows: traditional cement mortar (control mixture); three mixes with different percentages of LWFA (25%, 50% and 75%); three mixes with different percentages of MRA (2.5%, 5% and 7.5%); and three mixes consisting both types with determined ratios (25% LWFA+5% MRA, 50% LWFA+5% MRA and 75% LWFA+5% MRA). The flow ability of the mortars was 22±2 cm, and LWRM contained LWFA and MRA. The compressive and tensile strength decreased by approximately 64% and 57%, respectively, when 75% LWFA was used compared with those when the control mix was used. The compressive and tensile strength decreased when 5% MRA was used. By contrast, mixes with determined ratios of LWFA and MRA affected reduced unit weight, K-value and dry shrinkage.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.300-303
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• 2004

In this study, the mixing contents of ceramic powder and of shrinkage-reducing agent (SRA) influencing on the strength properties of MMA-modified polymer paste were examined. Regardless of SRA content, the flexural. the compressive and the adhesive strengths of the MMA-modified polymer paste tended to increase as the mixing content of ceramic powder increased. On the other hand, those strengths of the polymer paste tended to decrease as the mixing content of SRA increased without regard to the paste content. Furthermore. the adhesive strength of MMA-modified polymer paste in a wet condition decreased about $30-40\%$ of that in an air-dry condition without regard to the mixing content of ceramic powder and SRA.

• 한국세라믹학회지
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• 제44권10호
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• pp.548-553
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• 2007

Ceramic green sheets consisting Bi-based glass frit were fabricated for an application to PDP transparent dielectric front panel. The dispersion condition of the slurry for tape casting was pre-examined, and two kinds of hinder and plasticizer were used in the non-aqueous slurry system. In the fabrication process for the frit film, the properties such as dry and firing shrinkage, elongation, and transmittance were examined at the condition of various mixing ratio of plasticizers. In the mixing ratio of polyethylene glycol to dibutyl phthalate of 3:5wt%, a good adhesion, elongation and transmittance were observed at the firing temperature of $580^{\circ}C$. The photograph for the cross section of the interface was also showed a dense microstructure.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.793-798
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• 2003

The purpose of this study is to investigate the setting properties of polystyrene mortars using waste expanded polystyrene(EPS) solution-based binders. The binders for polystyrene mortars are made by mixing crosslinking agent with waste EPS solutions which prepared by dissolving EPS in styrene. Polystyrene mortars are prepared with various EPS concentrations of EPS solutions and crosslinking agent contents, subjected to a dry curing, and tested for working life, peak exotherm temperature and 10h-length change. From the test results, the working lives of polystyrene mortars are shortened with raising EPS concentration of EPS solution and crosslinking agent content. Low-shrinkage or non-shrinkage of polystyrene mortars should be accomplished by adjusting EPS concentration of EPS solution and crosslinking agent content.