• 폴리머
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• 제35권4호
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• pp.342-349
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• 2011

실리카의 표면 개질제인 vinyltriethoxysilane(VTEOS)의 함량에 따른 실리카로 보강된 실리콘 고무의 기계적 물성 변화 및 내열성, 내유성, 압축 영구줄음률, 반발탄성 및 가교밀도 변화를 연구하였다. 결과로 VTEOS의 함량이 2.0 phr까지 증가함에 따라 경도는 상승하였으나 인장강도 파단신율, 인열강도가 감소하였다. 내열시험에서는 VTEOS의 함량이 증가될수록 경도변화, 인장강도 변화율, 파단신율 변화율이 크게 감소하였다. VTEOS 2.0 phr에서 가장 우수한 내열특성을 나타내었다. 또한 VTEOS의 함량이 증가될수록 실리콘 고무의 내유성이 증진되었으며, VTEOS 미첨가 시보다 경도 하락폭이 크게 낮았으며, 파란신율 변화율은 약 2배 이상 감소하였다. 반발탄성도 VTEOS의 함량이 증가될수록 우수하였으며, 압축 영구줄음률 역시 VTEOS가 증가될수록 감소하였다. 가교실험 결과 VTEOS가 증가될수록 최대 토크값와 가교밀도가 크게 향상되었다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제28회 추계학술대회
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• pp.181-189
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• 1998

In order to investigate the effect of base oil composition on the electronic insulating oil's performances, an experimental study has been conducted using different oils. Owing to their properties, like lower pour point and gas absorbing, naphthenic base oils are used more often than paraffmic base oils for the electronic insulating oil application. Naphthenic and paraffinic base oils are significantly different in their aromatic hydrocarbon content. In this paper, PXE(para xylyl ethane), LAB(linear alkylbenzene), C13 aromatic hydrocarbon mixture and C17 aromatic hydrocarbon mixture are investigated regarding their influence on insulating oil's performances. According to present study, breakdown voltage decreased with increasing aromatic lydrocarbon content in a deep dewaxed paraffmic base oil. However, any changing in the dissipation factor was not recognizable at small treated level. Furthermore, the volume resistance was not influenced by aromatic hydrocarbon content. The gassing tendency was found as a highly sensible property, changing with treating aromatic hydrocarbons. The higher benzene ring content in the hydrocarbon, the better gassing tendency.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.99-108
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• 2018

An oil-tolerant and salt-resistant aqueous foam system was screened out as a possible lubricant to enable cold heavy oil transportation. The microstructures and viscoelasticity and effects of heavy oil, salt and temperature on the foam stability were investigated and new rheological and drainage models were established. The results indicate the foam with multilayered shells belongs to a special microcellular foam. The viscoelasticity could be neglected due to its low relaxation time. The drainage process can be divided into three stages. The foam with quality of 67.9% maintains great stability at high oil and salt concentrations and appropriate elevated temperature.

• 한국세라믹학회지
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• 제56권6호
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• pp.558-565
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• 2019

In this study, dimethyl silicone oil and liquid paraffin were combined and subsequently emulsified; the resulting mixture was innovatively incorporated into desulfurized gypsum to resolve its drawback of a poor water resistance. The waterproof mechanism of the composite emulsion and liquid paraffin emulsion with mass fractions of 1%, 2%, 3%, and 4% were investigated. The effect of the desulfurized gypsum on the waterproof performance and basic mechanical properties were also investigated. The configuration of the composite waterproofing agent was characterized by FTIR and ¹HNMR. The results showed that, compared with the traditional liquid paraffin emulsion-based waterproofing agent, the softening coefficient of the silicone oil paraffin composite emulsion-based water-repellent agent was increased by 60% and attained a value of 0.89. Combined with the waterproof mechanism and microscope morphology analysis of gypsum hydration products, the improvement in the water resistance of water resistance was primarily attributed to the formation of a silicone hydrophobic membrane between the crystals of the gypsum block; this ensured that water could not penetrate the crystal.

• The Korean Journal of Physiology and Pharmacology
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• 제4권2호
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• pp.91-97
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• 2000

The purpose of the present study was to determine the preventive effects of combined interventional trial of fish oil treatment and exercise training on insulin resistance of skeletal muscle in high-fat fed rats. Male Wistar rats were randomly divided into chow diet (CD), high-fat diet (HF), high-fat diet with fish oil (FO), high-fat diet with exercise training (EX), and FO+EX groups. The rats in control group were fed chow diet containing, as percents of calories, 58.9% carbohydrate, 12.4% fat, and 28.7% protein. High-fat diet provided 32% energy as lard, 18% as corn oil, 27% as carbohydrate and 23% as casein. The fish oil diet had the same composition as the high fat diet except that 100 g menhaden oil was substituted for corn oil. Insulin sensitivity was assessed by in vitro glucose transport in the soleus muscle after diet treatment and treadmill running for 4 weeks. While the FO or EX only partially prevented insulin resistance on glucose transport and visceral obesity induced by high-fat diet, these interventions completely corrected hyperinsulinemia and hyperglycemia from the high-fat diet. The rats in the FO+EX showed normalized insulin action on glucose transport, plasma chemicals and visceral fat mass. Insulin-mediated glucose transport was negatively associated with total visceral fat mass (r=－0.734; p＜0.000), plasma triglyceride (r=－0.403; p＜0.05) and lepin (r=－0.583; p＜0.001) concentrations with significance. Multiple stepwise regression analysis showed that only total visceral fat mass was independently associated with insulin-mediated glucose transport (r=－0.668; p＜0.000). In conclusion, combined interventional trial of FO+EX recovered insulin resistance on glucose transport of skeletal muscle induced by high-fat diet. Visceral fat mass might be more important factor than plasma TG and leptin to induce insulin resistance on glucose transport of skeletal muscle in high-fat fed rats.

• Elastomers and Composites
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• 제46권1호
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• pp.45-53
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• 2011

실란커플링제인 bis-(3-triethoxysilpropyl)tetrasulfide (TESPT)가 실리카 충전 오일씰용 NBR 복합소재의 물성에 미치는 영향에 대하여 연구하였다. 복합소재의 가교거동과 가교밀도는 ODR (oscillating disk rheometer)과 톨루엔 팽윤비 시험을 통하여 측정하였으며, 기계적 물성은 가황물을 공기 내열 노화 및 ASTM No.3 oil에 내유 노화시켜 시험 전 후 값을 UTM (universal testing machine)과 Shore A 경도계를 사용하여 측정하였다. 오일씰의 성능과 수명에 큰 영향을 미치는 복합소재의 탄성회복은 가황물에 굽힘 변형을 주어 노화시킨 후 시편이 회복되는 길이를 측정하여 회복 각(angle of recovery)을 계산하였으며, 저온에서의 탄성회복거동은 TR (temperature retraction) 시험을 통하여 측정하였다. 또한, Taber식 마모시험기를 사용하여 가황물의 내마모성을 측정하고 SEM(scanning electron microscope)을 사용하여 마모면의 형상을 관찰하였다. 시험결과 실리카가 충전된 복합물에 TESPT가 첨가되면 복합물의 흐름성이 향상되고 실리카와 NBR 간의 상호작용 및 가황물의 가교밀도가 향상되어 가황물의 경도, 100% 모듈러스, 탄성회복성, 내마모성, 내열노화성 및 ASTM No.3 오일에 대한 내유성이 향상됨을 알 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.406-409
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• 2002

The primary insulation system used in an oil-filled transformer is Kraft paper, wood, porcelain and, of course, oil. Modern transformers use paper that is chemically treated to improve its tensile strength properties and resistance to aging caused by immersion in oil. These insulation papers are mainly aged to thermal stress. Over the course of the insulation paper and oil's life it is exposed to high temperatures, oxygen and water. Its interaction with the steel of the tank and core plus the copper and aluminium of the windings will eventually cause the chemical properties of the oil to decay. High temperature have an effect on mechanical strength of cellulous paper using the layer insulation. We made two aging cell in which thermal aging tests of insulation papers and mineral oil are conducted. It is measured dielectric strength, number of acid, moisture, etc. of insulation paper and oil aged in the aging cells.

• Computers and Concrete
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• 제6권5호
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• pp.391-401
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• 2009

This paper presents a study of the strength and chloride penetration of blended Portland cement mortar containing ground palm oil fuel ash (POA) and ground river sand (GS). Ordinary Portland cement (OPC) was partially replaced with POA and GS. Compressive strength, rapid chloride penetration test (RCPT) and chloride penetration depth of mortars were determined. The GS only asserted the packing effect and its incorporation reduced the strength and the resistance to chloride penetration of mortar. The POA asserted both packing and pozzolanic effects. The use of the blend of equal portion of POA and GS also produced high strength mortars, save cost and excellent resistance to chloride penetration owing to the synergic effect of the blend of POA and GS. For chloride depth, the mathematical model correlates well with the experimental results. The computer graphics of chloride depth of the ternary blended mortars are also constructed and can be used to aid the understanding and the proportioning of the blended system.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.431-434
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• 2002

This paper reports on the evaluation of weathering resistance, tracking test and salt-fog of various kinds of cycloaliphatic epoxy systems. It was found that UV irradiation induced the loss of hydrophobic level due to the chain scission attack at the surface. It could be seen that samples containing an UV absorbent/antioxidant and a silicone oil additive knave a good performance in weathering ageing, whereas ATH filled ones have high resistance against tracking failure than others. Under salt-fog test, specimens mixed with silicone oil could suppress leakage current development. It was thought that silicone oil mixed into cycloaliphatic epoxy system could lead to lower the surface energy and to retain hydrophobic properties for a long time, which are desirable for outdoor performances.

• Natural Product Sciences
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• 제13권2호
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• pp.164-168
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• 2007

To investigate natural antibiotics from plant essential oils and to evaluate their synergism with current antimicrobial drugs in inhibiting antibiotic-resistant strains of Streptococcus pneumoniae. The minimal inhibitory concentrations (MICs) of eleven plant essential oils and their main components were established for two antibiotic-susceptible and two antibiotic-resistant strains of S. pneumoniae, using broth microdilution tests. Potential synergism with oxacillin, norfloxacin, or erythromycin was evaluated using a checkerboard microtitre assay. Among the tested oils, Mentha piperita oil and its main component, menthol, exhibited the strongest inhibitory activities against all of the tested strains. The activity of antibiotics against antibiotic-resistant strains of S. pneumoniae was enhanced significantly by combination with Mentha piperita oils and its main component, menthol. In conclusion, the combination Mentha piperita essential oil or menthol with antibiotics could be used to reduce the effective dose of antibiotic and to modulate the resistance of S. pneumoniae strains.