• Proceedings of the KSAR Conference
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• 2004.06a
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• pp.280-280
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• 2004

본 연구는 개 동결정액 희석액에 pentoxyfilline을 첨가하여 융해 후 정액성상에 미치는 영향을 조사하였다. 공시견은 2∼3세의 Beagle, English cockers spania, Collie, Grey hound, Shihtzu 5두를 공시하였다. 정액은 수압법 또는 인공질법으로 채취하였고 채취된 정액은 Rota 등(EYT : Egg-yolk Tris extender, 1995)의 방법에 따라 동결정액을 제조하였다. Pentoxyfilline은 동결 보호제가 들어 있는 2차 희석액에 0 mM, 1 mM, 3 mM 농도로 첨가하였으며, 5℃에서 2시간 glycerol 평형을 한 후에 액체질소에 10분간 예비 동결하여 동결정 액을 제조하였다. (중략)

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.196-196
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• 1994

DDS에 활용될 수 있는 고분자 소재를 개발할 목적으로 물성 및 응용성이 우수한 고분자 겔에 관한 연구를 수행하였다. Ethylene oxide,propylene oxide 각각의 copolymer인 poloxamer등의 prepolymer들을 triisocyanate로 가교시키고 diisocyanate 로 chain이 연장된 "soft hydrogel"을 제조하였다. 모델 약물을 선정하여 crosslinker와 extender의 조절에 따른 hydrogel의 약물 방출 조절능을 조사하였으며 그 기전을 규명하고자 하였다. 가교부위에 urethane bond를 함유한 soft hydtogel은 건조상태에서도 고무와 같은 전연성을 보여 일반적인 hydrogel과 대비되는 특성을 보였으며 이에 따른 다양한 활용성이 기대되었다. Extender및 crosslinker의 비율에 따라서 이 rubber elasticity가 조절되었다. 가교도가 감소할수록 팽윤도가 상승하였고 이에 따른 약물방출도 증가함을 확인하였다. 또한 Prepolymer의 분자량 및 친수/소수성등의 물성에 따라 약물방출을 조절할 수 있었다. 제조된 hydrogel에 조절방출시 필요한 기능을 부가시키고자 poly(carylic acid)류와 IPN 공중합체를 합성하여 물성을 조사하였고 비이온성/양이온성/음이온성 모델약물을 선정하여 pH에 따른 가변적 팽윤도와 이온성 상호작용등에 근거한 약물 조절방출기전을 조사하였다.기전을 조사하였다.

• Transactions on Electrical and Electronic Materials
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• v.14 no.4
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• pp.199-202
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• 2013

In order to study the effect of reactive diluents on the electrical insulation breakdown strength and mechanical properties of, a polyglycol and an aliphatic epoxy were individually introduced to an epoxy system. Reactive diluents were used in order to decrease the viscosity of the epoxy system; polyglycol acted as a flexibilizer and 1,4-butanediol diglycidyl ether (BDGE) acted as an aliphatic epoxy, which then acted as a chain extender after curing reaction. The ac electrical breakdown strength was estimated in sphere-to-sphere electrodes and the electrical breakdown strength was estimated by Weibull statistical analysis. The scale parameters of the electrical breakdown strengths for the epoxy resin, epoxy-polyglycol, and epoxy-BDGE were 45.0, 46.2, and 45.1 kV/mm, respectively. The flexural and tensile strengths for epoxy-BDGE were lower than those of the epoxy resin and those for epoxy-polyglycol were lower than those of the epoxy resin.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.2
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• pp.178-183
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• 2009

The developed in-flex system completed the wiring work with the plug-in connection. To maintain electrical and mechanical stability, and an insulation between the conductors was strengthened by forming a partition. Moreover, the error according to a bad connection was prevented by separating the inlet from the outlet of the electric trace and thus the quick construction become possible. The metal reinforcing material was added outside the upper case and lower case. The fire-resistance efficiency was maximized in order to minimize a damage by the fire. As to the developed system, we found that it takes shorter time to complete installation than the rigid steel conduit wiring work, and that about 25 % of construction cost was saved because the labor costs decrease due to the shorter construction period of time.

• Transactions on Electrical and Electronic Materials
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• v.14 no.6
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• pp.317-320
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• 2013

Partial discharge resistance for the epoxy systems with two diluents was investigated in the rod-plane electrodes arrangement, and the effect of electric frequency on the partial discharge resistance was also studied. Diglycidyl ether of bisphenol A (DGEBA) type epoxy was used as a base resin, and 1,4-butanediol diglycidyl ether (BDGE) or polyglycol (PG) as a reactive diluent was introduced to the DGEBA system, in order to decrease the viscosity of the DGEBA epoxy system. BDGE was acted as a chain extender, and PG acted as a flexibilizer, after the curing reaction. To measure the partial discharge resistance, 5 kV alternating current (ac) with three different frequencies (60, 500 and 1,000 Hz) was applied to the specimen in a rod-plane electrode arrangement, at $30^{\circ}C$. PG had a good effect, while BDGE had a bad effect on the partial discharge resistance of the DGEBA system, regardless of the electric frequency.

• Korean Journal of Animal Reproduction
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• v.5 no.2
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• pp.43-48
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• 1981

This experiment was carried out with the purpose to get some information about the properties of Simmental bull semen during summer season. The results obtained were summarized as follows: 1. Semen volume per ejaculation, sperm concentration and sperm viability were averaged 5.16ml, 6.6billion and 65%, respectively. 2. Percentage of motile sperm after dilution in skmmilk solution and trisbuffer for 5 days were 34.16% and 35.0%, respectively. 3. Viability of spermatozoa frozen in skimmilk extender and trisbuffer for 5 days were 20. 83% and 25.66%, respectively. 4. Percentage of live sperm, MRT and pH value were 71.8∼72.1%, 8.40∼8.21 minutes and 6.78, respectively. 5. Diluted semen showed strong resistance to the cold shock than that of fresh semen. 6. Rscovery of sperm motility after freezing for 24 hours was relatively weak.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.7
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• pp.642-646
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• 2008

We have developed a vision based crack detection system and algorithm to inspect base side of bridges. After human operator decides from vision images captured if lines on base side are cracks or dirt, our algorithm finds automatically the length, the width and the shape of cracks. The system has been tested with a robot extender on a truck in real environment and has been proved to be very useful to reduce inspection cost as well as the data management.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.425-428
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• 2003

This study deals with the mechanical properties of polymethyl methacrylate(PMMA) mortars without crosslinking agent. Waste expanded polystyrene(EPS) is used as a multifunctional admixture such as a thickener, a extender, a shrinkage reducing agent, a assistant to polymerization. PMMA mortars are prepared with various EPS contents of binder and subjected to a dry and a dry/heat combined curing, and tested for working life, flexural and compressive strengths. From the test results, the working life of PMMA mortars without crosslinking agent is shortened with raising EPS content of binder. The flexural and compressive strengths of the PMMA Mortars are decreased somewhat with increase in the EPS content. PMMA mortars with good mechanical properties could be manufactured without any crosslinking agent and their properties would be controled by adjusting EPS content of binder.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.4 s.34
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• pp.43-50
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• 1999

The planarized $SiO_2$ particles were prepared by two-step reduction method of making much smaller particles, micron-sized ones, to improve spreadability, adherence, and smoothness. Various pigments known as flaky extender usually have terrace layers on their surfaces, but $SiO_2$ particles in this study exhibit a smooth surface structure. These single $SiO_2$ particles were used as core particles to prepare the composite particles coated with ultra fine $TiO_2$ particles by a homogeneous precipitation method. The thickness and the morphology of the deposited $TiO_2$ layers could be modified by adjusting the reactant concentrations, the reaction time and the temperature. The characteristics of $SiO_2/TiO_2$ composite in the field of color cosmetics are to give an UV-cut effect and to enhance the chroma of human skin color, one of optical properties.

• Journal of the Korean Applied Science and Technology
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• v.22 no.4
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• pp.355-361
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• 2005

The physical characteristics of polyurethane were examined by SEM, FT-IR tensile strength and mole % [NCO/OH]. Growing concerns in the environment-friendly architecture and public works have led to the development of solvent-free formulations that can be cured and foamed in air. Compared with general packing materials, this resin is much stronger in intensity and much longer in durability. Polyurethane foam resins were mainly composed of polyol, MDI, silicone surfactant, fillers, catalyst and blowing agent. The rigid foam of polyurethane in mechanical characteristics were due to chain extender and the increase of mole % [NCO/OH]. The change in the microstructure of polyurethane should be taken into account when considering the process of construction and durability through the polyurethane polymer resin in lots of industries.