• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.536-541
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• 2000

In recent years there has been a steady increase in geoenvironmental engineering research where geotechnical engineering has been combined with environmental concerns in the field of construction and industrial waste reusing in civil works. Many of these projects involve some investigation on the characteristics of geotechnical and environmental properties. In this study, investigation and test on the characteristics of demolished waste concrete was carried out to detect the physical, mechanical, and environmental properties for reusing as embankment and backfill materials in civil works.

• 콘크리트학회지
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• 제9권2호
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• pp.137-144
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• 1997

발수제의 유무와 알루미늄분말의 분말도 및 첨가량을 조절하여 비중을 0.4에서 0.7로 변화시켜 비중과 ALC의 기초물성, 내동해성 및 내구성과의 관계를 조사하였다. 압축 및 인장강도는 비중이 0.4에서 0.7로 증가함에 따라 발수제의 첨가량에 관계없이 증가하였고 발수제의 첨가량이 증가하면 내동해성은 개선되었으며 흡수율은 감소하였다. 입경이 작은 AI분말을 이용항 제조한 ALC의 박리에 의한 체적감소율은 낮게 나타났으며 일면동결지속시험 및 기중동결수중융해시험에서도 내동해성이 우수한 것으로 나타났다.

• 한국환경생태학회:학술대회논문집
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• 한국환경생태학회 2006년도 임시총회 및 학술논문발표회
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• pp.245-249
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• 2006

• 한국재료학회지
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• 제29권7호
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• pp.399-407
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• 2019

This research is carried out to analyze the effects of Styrene and PVP on the properties of silicone hydrogel lenses. Styrene group and PVP(Polyvinylpyrrolidone) are used as additives for a basic combination containing silicone monomer, TSMA(trimethylsilyl methacrylate) and DMA(n,n-dimethylacrylamide) added to the mix at ratios of 1~10 %. Silicone hydrogel lens is produced by cast-mold method. The polymerized lens sample is hydrated in a 0.9 % saline solution for 24 hours before its optical and physical characteristics are measured. Measurement of the physical characteristics of the produced material shows that the refractive index is 1.3682~1.4321, water content 77.11~45.73 %, visible light transmittance 95.14~88.20 %, and tensile strength 0.0652~0.3113 kgf. The results show a decrease of refractive index as the ratio of additives and water content decreases. The result of the stabilization test of polymerization show an increase of extractables along with increase of the ratio of additives, but the difference is not significant for all samples, so it can be judged that the stabilization of the polymer is maintained. Therefore, the additions of styrene and PVP should be taken into consideration for their effects on the physical properties of silicone hydrogel lens.

• 한국도로학회논문집
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• 제15권2호
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• pp.65-71
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• 2013

PURPOSES : The objective of this study is to evaluate the effect of physical characteristics of emulsion asphalt and aggregate on performance of chip seal pavements. METHODS : In order to evaluate the performance of chip seal materials, the sweep tests and Vialit Plate Shock tests were conducted on the mixtures with five emulsion asphalt binders and three aggregate types. The sweep tests was intended to investigate the change of bonding properties between emulsion asphalt and aggregate with curing time. The Vialit Plate Shock test was used to evaluate the bonding properties of chip seal materials at low temperatures. RESULTS : Results from sweep tests showed that polymer modified emulsion asphalt can reduce the curing time by 1.5 hour comparing with typical emulsion asphalt. It is also found that the Flakiness Index of aggregates and absorption rate of binder are the major factors affecting the bonding properties of chip seal materials. The Vialit Plate Shock test results showed that the average aggregate loss of CRS-2 is ten times higher than CRS-2P No.2 indicating that the use of polymer additives in emulsion asphalt can improve the performance of chip seal materials in low temperature region. CONCLUSIONS : The use of polymer in emulsion asphalt can decrease the curing time of chip seal materials and increase the bonding properties between aggregates and asphalt binder. It is also concluded that the lower Flakiness Index and absorption rate of aggregates can improve the performance of chip seal pavement.

• 공업화학
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• 제10권7호
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• pp.1066-1072
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• 1999

고기능성 건설재료로 활용하기 위하여 불포화폴리에스테르수지를 사용한 폴리머 콘크리트의 물성에 대하여 조사하였다. 탄산칼슘(충전제)의 첨가량(5~20 wt %)과 세골재의 첨가량(10~50 wt %)에 따라 다양한 배합의 공시체를 제작하여 압축 및 휨강도, 흡수시험, 내열수성시험, 내산성시험, 세공분포측정 및 SEM에 의한 미세조직 관찰등을 실시하였다. 그 결과 폴리머 콘크리트의 압축강도와 휨강도는 시멘트 콘크리트보다 4배 정도 향상되었고, 흡수율은 1/100로 감소되었으며, 내산성시험에 의한 중량감소율은 1/27로 현저히 감소되었다. 내열수성시험후에 측정한 폴리머 콘크리트의 압축 및 휨강도는 모두 내열수성시험전에 측정한 강도에 비하여 67%, 47%로 각각 감소되었으며 폴리머결합재의 분해에 의하여 세공량과 세공율은 크게 증가되었다.

• Restorative Dentistry and Endodontics
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• 제20권1호
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• pp.142-151
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• 1995

The purpose of this study was to compare and estimate the physical properties of five root canal sealers classified Calciobiotic root canals sealer as calcium hydroxide based sealer, Apatite root sealer type II as calcium phosphate based sealer, AH-26 as resin based sealer, Canals and Pulpdent root canals sealer as zinc oxide eugenol based sealer. The author investigated dimensional change and flow rate of canal sealers, diametral tensile strength and shear bond strength of sealers to dentin to evaluate the physical properties on affect of complete obturation of root canal and performed the total 100 specimens of each 25 sealers under the condition of root temperature according to manufacturer's instructions. All specimens were stored at $37{\pm}1^{\circ}C$ in 100 % relative humidity. A microscope for measurement of micro distance is used for the dimensional change test and evacuation methods using vaccum were used for the flow rate test. The result differed by the storage time measured on the tests of diametral tensile strength and shear bond strength to dentin. The following results were obtained ; 1 On the test of dimensional change, Canals and Pulpdent expanded slightly, AH-26 and Apatite showed the severe shrinkage after 48 hours. 2. AH-26 and Apatite were the excellent with each 24.59mm, 31.19mm after 3 minutes in the aspect of flow property. 3. On the diametral tensile strength, Calciobiotic root canals sealer showed the highest strength with 27.13kg/$cm^2$ after 48 hours, Apatite root sealer type II showed highest strength with 84.57kg/$cm^2$ after 120 hours. 4. On the shear bond strength to dentin, AH-26 was most excellent with 55.73kgf/$cm^2$ after 24 hours and with 134.71kgf/$cm^2$ after 120 hours.

• Safety and Health at Work
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• 제10권3호
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• pp.314-320
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• 2019

Background: Sitting posture may be related to risk factors, including inadequate weight-bearing support, particularly when maintained for long periods. Considering that body weight is loaded in a closed support system composed of the seat, backrest, floor and working surface, the aims of the present study were to describe the development of an ergonomic sitting workstation to continuously record weight-bearing at the seat, chair, backrest, work surface, and floor and to test its measurement properties: reproducibility, criterion-related validity, and sensitivity. Methods: Rigid bodies (1 to 30 kg) and participant weights were recorded to evaluate the workstation measurement properties. Results: Rigid body tests showed variation values less than 0.050 kg on reproducibility test and errors below 5% of measured value on criterion validity tests. Participant tests showed no statistically significant differences between repeated measures ($p{\geq}0.40$), errors were less than 2% of participant weights an sensitivity presented statistically significant changes (p = 0.007). Conclusion: The sitting workstation proposed showed to be reliable, valid and sensitive for use in future ergonomic studies to evaluate the sitting posture.

• 한국조경학회지
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• 제30권1호
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• pp.96-104
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• 2002

This study was conducted to investigate physical properties of soil and turfgrass wear characteristics within turfgrasses inside or outside the stadium A 1/1000 scale model Inchon world cup soccer d[me was constructed for this test. Turfgrasses planted inside and outside the model dome were; Kentucky bluegrass(KB), Kentucky bluegrass + perennial ryegrass mixture (KB+PR), Kentucky bluegrass + tall fescue + perennial ryegrass mixture (KB+TF+PR), Zoysia japonica 'Anyangjungzii'(ZA) and Zoysia japonica 'Zenith\`(ZZ). The rootzone was constructed by the multi-layer method (United States Golf Association method). Traffic on turfgrasses was treated with a 120kg roller. Surface soil hardness, soil penetration and water infiltration values on cool-season grasses(KB, KB+PR, KB+TF+PR) was found to be better for soccer play compared to zoysiagrasses(ZA, ZZ). No big differences in surface soil hardness, soil penetration and water infiltration values were found between inside and outside of the model dome. Wear damage on cool-season grasses caused by the traffic treatment was low compared to zoysiagrasses. However, there was no difference in wear damage by the traffic treatment within cool-season grasses while wear damage on ZA was higher than on ZZ within zoysiagrasses. It could be concluded that physical properties and wear characteristics on cool-season grasses were much better for soccer play than on zoysiagrasses.

• 한국의류학회지
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• 제24권6호
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• pp.828-837
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• 2000

The purpose of this study was to evaluate the physical properties and the hand of bast/man made fiber mixed fabrics compared to linen. The mixed fabrics were made by rayon, polyester and modal fiber as warp yarn, and ramie, flax, rayon/flax and cotton/flax as weft yarn. The crease resistance, drape, tensile strength/extension, water absorbancy and warmth retention were measured for test fabrics. The mechanical properties were measured by Kawabata system, and the hand value was calculated by previously developed equation. The results obtained from this study were as follows: The crease resistance and drape properties of bast/man made fiber mixed fabrics were improved compared to those of linen. The tensile strength of polyester/bast fiber mixed fabrics increased compared to those of linen, but rayon/bast and modal/bast fiber mired fabrics decreased. The extension of all mixed fabrics was increased compared to that of linen. The rayon/ramie and modal/ramie mixed fabrics showed lower warmth retention than linen. The mixed fabrics used rayon and modal as warp yarn showed higher water absorbancy than linen. The Koshi and Hari hand value of all mixed fabrics showed lower than those of linen. Fukurami hand value showed little difference between mixed fabrics and linen. Shari, Kishimi, and Shinayakasa hand value of rayon/bast and modal/bast fiber mixed fabrics showed higher than those of linen.