• 한국세라믹학회지
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• 제37권8호
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• pp.751-759
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• 2000

Effects of the dosage change, from 0 to 2.0 wt% based on cement weight, of naphthalenic (NSF) and polycarboxylic(NT-2) superplasticizers, on the fluidity of cement paste substituted by 10 wt% II-anhydrite and fly ash respectively as well as II-anhydrite and fly ash itself were investigated. Dispersion properties between particles in suspension were investigated by zeta potential test. Initial fluidity and slump loss in the paste system were observed through mini-slump and apparent viscosity changes with elapsed time. Zeta potential on the particle surface was a tendency to increase according to increasing of NSF dosage. Especially, zeta potential of fly ash has the highest value among all particles equivalent to NSF dosage. In the fluidity of cement paste substituted by inorganic particles, the specimen with substitution of 10 wt% II-anhydrite and fly ash for cement was more effective than cement itself to improve initial fluidity and retain stable fluidity of cement paste. In addition, effect of NT-2 and NSF to improve the fluidity of cement paste, addition of 1.0 wt% NT-2 was more effective than 1.5wt% NSF.

• Elastomers and Composites
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• 제29권3호
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• pp.226-233
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• 1994

The properties of the mixed prepolymer-urethane in the range of 10-40 phr were observed. LBR and LCR have same functional group but different in structure of molecular. The viscosity of mixture depending on content of rubber, adhesive strength, thermal property and compatibility with a diluted solvent are as follows: 1. The viscosity of the mixture was influenced by solubility of the diluent for urethane resin and liquid rubber. 2. Adhesive strength showed the highest value at 30phr rubber, decreased gradually at above 30phr rubber. And LBR revealed better physical property than that of LCR. 3. The most effective factors affecting adhesive strength are molecular structure of rubber, the type of solvent, and volatility. 4. Urethane resin containing LBR showed better compatibility for solvent and faster drying velocity. 5. LBR showed more favorable compatibility and dispersion state than those of LCR by analyzing the results of SEM.

• 한국자동차공학회논문집
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• 제7권6호
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• pp.115-122
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• 1999

A friction tester to measure friction force generated at the interface between the piston ring and the cylinder liner was developed. Modified piston ring is bar-shaped and 100mm long. Surface of the modified piston ring is machined by the profile grinding machine to be formed as a shape of an arc of a circle. Measured data are treated as mean effective friction force and power loss. From this test it can be confirmed that friction force is deeply affected by surface shape of the piston ring and viscosity of supplied oil. Friction force is deeply affected by surface shape of the piston ring and viscosity of supplied oil. Friction force is decreased and power loss is increased with increasing velocity. And it is known that region of mixed lubrication is broader than estimated with theoretical analysis. it is expected that this tester can be used as the optimization tool of the surface shape of the piston ring at the first stage of development of the piston rings.

• 대한기계학회논문집B
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• 제20권9호
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• pp.2909-2915
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• 1996

Precise and accurate pressure measurements are obtained using deadweight piston gauges. Pressure distribution and elastic distortion in the piston-cylinder unit are the leading factors in determination of effective area. The distortion depends upon the pressure distribution in the clearance between piston and cylinder and those are coupled each other. Considering the viscosity pressure relation of oil and governing flow equation in the clearance, a new numerical iterative algorithm is developed. The disagreement between the monotonous and sharp pressure profiles is an indication that the pressure profile will be different for each piston and cylinder unit due to material variances.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1999년도 제30회 추계학술대회
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• pp.184-189
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• 1999

This Paper presents the friction and lubrication charateristic related with oil aeration. It is well known that oil aeration occurs severe problem on lubrication system, in particular, in the engine bearings and hydraulic lash adjuster. In this study, engine tests were carried out in motoring conditions. In order to investigate oil aeration characteristics, we measured oil aeration with respect to oil temperature, oil viscosity, modified oil drain system. From the results, we concluded that aeration can be reduced by improving oil drain system and FMEP can be reduced by minimising of aeration.

• Journal of Pharmaceutical Investigation
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• 제25권4호
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• pp.339-345
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• 1995

For the effective treatment of aphthous stomatitis, the matrix type mucoadhesive patches containing triamcinolone acetonide have been formulated. The drug layer was obtained by drying the polymer gel which was prepared with carbomer 934P, ammoniomethacrylate copolymer, titanium dioxide and polyethylene glycol 400. The effects of the content of additives on physical characteristics of the polymer gel and the drug layer were evaluated. The addition of carbomer increased the yield point and the zero-shear viscosity of polymer gel as well as the thickness, the water absorption ratio, the adhesive time and $T_{50%}$ of drug layer. The adhesive time and the water absorption ratio of drug layer were also improved by the addition of ammoniomethacrylate copolymer, but the addition of titanium dioxide had decreased the zero-shear viscosity of polymer gel and the adhesive time of drug layer.

• 조명전기설비학회논문지
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• 제29권12호
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• pp.28-32
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• 2015

In this work, we reported fabrication of sealing the glass substrate using laser treatment at low temperature for electrochemical luminescence (ECL) cell. The laser treatment at temperature is using laser diode. The glass substrate sealing by laser treatment tested at 3-10W, 2-5 mm/s for build and tested. The sealing laser treatment method will allow associate coordination between the two glass substrate was enclosed. The effect of laser treatment to sealing the glass substrate was found to have cracks and air gap at best thickness of about 550-600 im for condition 3 W, 3 mm/s. The surface of sealing was roughness which was not influent to electrodes It can reduce the cracks, crevices and air gaps as well, improves the performance viscosity in butter bus bar electrodes. Therefore, it is more effective viscosity between two FTO glasses substrate.

• 패션비즈니스
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• 제26권6호
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• pp.105-115
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• 2022

Wearing a mask is still advised since COVID-19 continues to spread. However, masks may also irritate the skin and cause mask acne, often known as "maskne", which is a type of acne mechanica caused by friction between the skin and clothing. Therefore, there is a need to develop an effective maskne cosmetic. In this study, we made the maskne cosmetics containing humulus lupulus extract and copper tripeptide-1 and investigated its stability and safety. To measure stability, a centrifugation test and heat-cool cycling were done, and changes in viscosity and pH were measured for 8 weeks. The Cumulative Irritation Test (CIT, WKIRB-202111-HR-096) was performed and positive reactions were determined by the ICDRG criteria. The results indicated that the samples were stable after centrifugation, temperature cycling, viscosity, and pH tests. In addition, cosmetic safety test results revealed that maskne cosmetics containing humulus lupulus extract and copper tripeptide-1 did not cause any skin responses. These findings indicate that prepared maskne cosmetics' stability and safety were comparable to those of currently available commercial cosmetics.

• Applied Biological Chemistry
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• 제33권3호
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• pp.209-215
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• 1990

압출면의 영양강화 목적으로 대두분을 소맥분과 섞어 점도 특성을 고찰하고, 압출면을 제조할 후 조리시험, 조리면의 조직감시험 및 관능정사 결과 대주분 첨가비율이 증가함에 따라 복합분의 점도, 조리면의 조직감 및 조리품질은 저하하였다. 대두분 10% 첨가 압출면에 각종 첨가제의 첨가효과를 보면, 첨가제의 첨가량이 증가함에 따라 점도는 증가하였으며, 첨가제 중에서는 xanthangum이 가장 효과적이었다. 조직감에 있어서는 Na-carboxymethyl cellulose 2.0%, guar gum 2.0%, xanthan gum 1.0%에서 밀가루면과 비슷한 값을 나타내었으며, 관능검사도 이와 유사한 결과를 보였다.

• 폴리머
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• 제30권2호
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• pp.118-123
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• 2006

폴리(부틸렌 테레프탈레이트)(PBT)와 폴리(에틸렌 테레프탈레이트)(PET)의 용융 가공시 발생하는 상호에스테르 교환반응이 PBT/PET 블렌드의 유변 물성에 미치는 영향에 대하여 살펴보았다. PBT에 PET를 용융 블렌딩하면 PET의 상대적인 낮은 점도에 의하여 PET의 함량이 증가할수록 PET의 점도가 감소됨을 알 수 있었으며 이와 함께 용융가공시 발생하는 분자량 감소와 PBT와 PET 상호간에 발생하는 상호에스테르 교환반응에 의하여 추가적인 용융점도 감소가 있음을 확인하였다. 또한 PBT와는 달리 윤활제로 사용한 calcium stearate(CaST)는 PBT/PET 블렌드에서 윤활 작용은 미약한 반면 이들 블렌드의 열분해에 따른 분자량 감소와 상호에스테르 교환반응을 촉진하여 추가적인 용융점도 감소를 초래함을 알 수 있었다.