• Journal of Electrical Engineering and Technology
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• 제11권3호
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• pp.690-698
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• 2016

In this paper, a study is carried out to investigate the dielectric, physical and chemical properties of Palm Oil (PO) and Coconut Oil (CO) under open thermal ageing condition. The type of PO used in this study is Refined Bleached and Deodorized Palm Oil (RBDPO) Olein. The ageing experiment was carried out at 85 ℃ and 115 ℃ for 1, 3, 5, 7 and 14 days. Several parameters were measured such as AC breakdown voltage, dielectric dissipation factor, relative permittivity, resistivity, viscosity, moisture and acidity throughout the ageing duration. Based on the study, it is found that there are no significant changes on the AC breakdown voltages and relative permittivities for both RBDPO and CO. At ageing temperature of 115℃, there are clear reduction trends of dielectric dissipation factor for CO and resistivities for most of RBDPO. On the other hand, no clear trends are observed for viscosities, moisture and acidities of RBDPO and CO throughout the ageing duration.

• 한국응용과학기술학회지
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• 제13권2호
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• pp.39-46
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• 1996

Durable softening water-repellenting agent such as PODCW, PDDCW and PEDCW were prepared by blending cationized compound such as poly(octadecyl methacrylate-co-2-diethylaminoethyl methacrylate)[PODC], poly(2-dodecyl methacrylate-co-2-diethyl-aminoethyl methacrylate)[PDDC] and poly(2-ethylhexyl methacrylate-co-2-diethyl-aminoethyl methacrylate)[PEDC], and cationized compound of fatty carbamide, of which synthetic methods were reported in the previous paper, waxes, and emulsifiers. The results of physical tests of the P/C blended fabrics treated with PODCW, PDDCW and PEDCW with and without textile finishing resin, showed a remarkable improvement of the physical properties. The prepared water-repellenting agents, PODCW-6 and PDDCW-1, were treated on P/C blended fabrics with and without resin. For any cases, there are a little changes between initial water repellency and repellency after 3 times washing of the fabrics. Therefore, the water-repellenting agents proved to be a durable agents, and initial water $100^{+}$ and $90^{+}$ point, respectively.

• 한국약용작물학회지
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• 제6권2호
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• pp.91-95
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• 1998

추출조건에 따른 지골피의 몇가지 물리적 성질 및 화학성분조성을 조사하였다. 1. 고형분과 총당함량은 물추출이 에탄올 추출물보다 높았으나 반면에 탄닌산함량은 에탄올 추출물에서 높았다. 2. 지골피 물추출물이 탁도와 갈색도가 에탄올추출물보다 높았으며 색도 중 적도와 황색도는 유사하였다. 3. 용매별 분획추출결과 수율은 물 > n-부탄올 > 에틸에텔 > 초산에 틸 분획순으로 증가하였다.

• 한국안광학회지
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• 제16권3호
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• pp.237-245
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• 2011

목적: 안경 렌즈에 물리적, 화학적 자극이 반복적으로 가해졌을 때 렌즈 코팅막의 기능에는 어떠한 변화가 나타나는 지를 알아보고자 하였다. 방법: CR-39 재질의 안경 렌즈 표면에 물리적, 화학적 자극으로 테이프 떼기, 아세톤 문지르기, 아세톤에 침윤 및 증류수에 침윤하기를 시행한 후 렌즈 표면의 변화, 광투과율 변화, 김서림 시간 변화 및 손상된 렌즈 표면의 안정성 여부를 측정하였다. 결과: 하드 코팅의 기능 변화를 알아보기 위한 표면관찰시 아세톤에 침윤한 안경 렌즈만이 침윤 30분 후부터 표면의 변화가 나타났다. 반사방지 코팅의 기능 변화를 알아보기 위한 광투과율 측정시 증류수에 180분간 침윤한 안경 렌즈는 1% 정도의 미세한 감소를 보인 반면 아세톤에 침윤시킨 렌즈에서는 침윤 60분 후 반사방지 코팅의 기능이 거의 소실됨을 알 수 있었다. 안티포그 코팅의 기능 변화를 알아보기 위한 김서림 지속시간 측정시 아세톤에 침윤시킨 안경 렌즈에서 김서림 지속시간이 증가하였다. 자극에 의해 손상받은 코팅막의 안정성을 알아보았을 때 테이프로 떼어내기, 아세톤으로 문지르기, 증류수에 침윤 및 아세톤에 침윤시킨 렌즈 표면의 코팅 손상이 관찰되었다. 결론: 반복적인 물리적, 화학적 자극으로 인하여 안경 렌즈의 코팅 변화가 관찰되었으므로 안경 조제 과정 중이나 안경 착용 시 이에 대한 주의가 요구된다.

• 한국건축시공학회지
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• 제7권4호
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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.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 토목섬유 학술발표회 논문집
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• pp.39-55
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• 1999

Geotextile composites to improve the weather ability were composed of recycled polyester geotextile with carbon black as ultraviolet stabilizer and polypropylene geotextile by needle-punching method, and evaluated physical properties, ultraviolet resistance and chemical stability. Retention ratio of tensile properties of non woven polypropylene geotextiles were decreased about 50% by the exposed condition with ultraviolet but those of geotextile composites were slightly decreased than polypropylene geotextiles. Geotextile composites which have larger weights of polyester geotextile were more stable against ultraviolet. For chemical stability, the changes of tensile properties of geotextile composites were in the range of -20~＋10% at the various chemical conditions.

• 공업화학
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• 제22권6호
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• pp.664-671
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• 2011

무촉매 공기 브로잉 공정에서 석유계 감압 잔사유로부터 세미-부로운 아스팔트를 제조하는 경우, 시간에 따른 아스팔트의 조성, 구조, 물리적 성질의 변화를 조사하였다. 공기 브로잉에 의해 지방족 탄화수소 성분이 방향족 탄화수소 성분으로 전이되고, 고분자화 되어 아스팔텐 성분이 증가함을 박막크로마토그래피를 이용한 조성 분석에서 관찰하였다. 처리시간에 따른 방향족화와 고분자화 정도의 증가는 $^1H-NMR$, 열시차분석, 그리고 열중량분석에서도 확인할 수 있었다. 이러한 아스팔트의 조성과 구조의 변화는 침입도의 감소, 연화점과 인화점의 증가를 초래하였다.

• 대한화학회지
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• 제54권1호
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• pp.105-109
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• 2010

Propylene glycol을 첨가제로 사용하여 HEMA (2-hydroxyethyl methacrylate)와 교차결합제인 EGDMA (ethylene glycol dimethacrylate) 그리고 개시제인 AIBN(azobisisobutyronitrile)을 사용하여 공중합 하였다. 생성된 고분자의 물리적 특성을 측정한 결과, 함수율 37.06~38.71%, 굴절률 1.492~1.432, 가시광선 투과율 89.4~91.5%, 인장강도 0.1416~0.2302 kgf 그리고 접촉각의 경우 $38.60{\sim}53.53^{\circ}$ 범위의 분포를 나타내었다. 따라서 propylene glycol을 첨가한 콘택트렌즈 재료의 경우, 기본적인 콘택트렌즈의 물성을 만족하였으며 함수율의 큰 변화를 나타내지 않으면서도 습윤성과 인장강도를 증가시키는 결과를 보여주었다.

• 한국토양비료학회지
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• 제49권4호
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• pp.341-346
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• 2016

This study was conducted to analyze soil physico-chemical properties of agricultural land composed from the river-bed sediments. We investigated the changes of soil physico-chemical properties at 30 different sampling sites containing paddy, upland and plastic film house from 2012 to 2015. pH, exchangeable calcium and magnesium decreased gradually in paddy soils during the four years, whereas the available $P_2O_5$, exchangeable Ca, Mg and EC increased in upland and plastic film house soil. For the soil physical properties, bulk density and hardness of topsoil were $1.47g\;cm^{-3}$ and 21.5 mm and those of subsoil were $1.71g\;cm^{-3}$ and 25.7 mm in paddy soils. In upland soils, bulk density and hardness of topsoil were $1.48g\;cm^{-3}$ and 15.9 mm and those of subsoil were $1.55g\;cm^{-3}$ and 16.9 mm. In plastic film house soils, bulk density and hardness of topsoil were $1.42g\;cm^{-3}$ and 14.4 mm and those of subsoil were $1.40g\;cm^{-3}$ and 18.5 mm, respectively. The penetration hardness was higher than 3 MPa below soil depth 20 cm, and it is impossible to measure below soil depth 50 cm. As these results, in agricultural anthropogenic soils dredged from river basins, the pH, amount of organic matter and exchangeable cations decreased and soil physical properties also deteriorated with time. Therefore, it is needed to apply more organic matters and suitable amount of fertilizer and improve the soil physical properties by cultivating green manure crops, deep tillage, and reversal of deep soils.

• Ocean and Polar Research
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• 제25권4호
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• pp.653-662
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• 2003

Changes in the area of geo-ecosystem $(62^{\circ}09'S,\;58^{\circ}31'w)$ reflect climatic changes in the South Shetland Islands. Air temperature and deglaciation will increase. The ice-free space area at the SSSS 8- (ASPA 121) site has enlarged threefold during the last 21 years, thus creating conditions for inhabitation and succession. Wind, water and snow play important roles in transportation of geochemical components. They distribute nutrients, mineral substances, seeds, fragments of plants and animals, etc. Plant and animal colonization is patchy and it happens at random in an 'island' - like manner. The colonization pattern is dependant, to a high degree on physical factors. The newly uncovered ice-free areas are at first inhabited by a vascular plant known as the Deschampsia antarctica. The border of the land-oasis with Admiralty Bay is the place where the processes related to animal feeding at the sea and reproduction on the land take place. Bird colonies and pinniped lairs form centers of fertilization surrounded by high chemical gradients dependent on the direction of the flow of nutrients $(e.g.\;NH_4)$. During the last 25 years, the numbers of penguins in this region have decreased, and thus the amount of materials excreted on land has diminished. The numbers of fur seals change in multi-annual cycles, and their migration into this area is related to the E1 $Ni\~{n}o$ phenomenon. The numbers of elephant seals in the area did not change. Organic matter deposited by the sea onto the shore are a source of nutrients and deficient chemical elements on land. Mineral matter is washed out into the waters of Admiralty Bay. These processes change seasonally, and multi annually. Negative effects on the environment at Arctowski Station induced by man are slight, but noticeable nevertheless. Physical processes have the largest influence on the living conditions and distribution of plants and animals, and as a consequence, on the functioning of the geo-ecosystem in the coastal-shore zone of the Maritime Antarctic.