• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.79-82
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• 2005

Fresnel lens has number of applications in the optical systems because of its advantages. It is nearly flat lens that has small weight. It is conventionally used in lighthouse beacons, condensing unit of overhead projector and etc. Recently, demands of small size optical systems such as display units, information storage systems, optical detecting units had increased. Conventional manufacturing process of high quality Fresnel lens is direct machining. But it is not suitable for mass production because of high cost and long cycle time. Replication process is more suitable for mass production. But the Fresnel lens has number of sharp blade shape prism. In the replication process, this blade shape causes defects that can affect optical efficiency. In this study, replication process of blade shape pattern that has maximum height of $280{\mu}m$, aspect ratio 1.4 for Fresnel lens application.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.157-160
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• 2008

본 연구에서는 디스크 이동식 폐타이어 열분해 실증 설비(10톤/일)를 설계, 제작 그리고 시운전을 통하여 열분해 설비의 안정적인 연속 운전이 가능함을 확인하였다. 시운전 결과 반응기 내부 온도는 $500{\sim}600^{\circ}C$, 내부 압력은 $-80{\sim}-100mmHg$, 체류시간은 $60{\sim}90min$ 범위에서 안정적인 열분해가 일어났다. 또한 이번 과제 수행을 통해NC 가스의 연소기를 개발 적용하여 NC 가스의 열분해 열원으로 사용 가능성을 확인하였으며, NC 가스 연소 시 대기 측정을 통하여 규제치도 만족함을 확인할 수 있었다. 지금까지 나온 결과는 장기 연속 운전과 scale-up을 위한 기초 자료가 될 것이다.

• Textile Coloration and Finishing
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• v.8 no.1
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• pp.73-82
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• 1996

The photochromic dye(spiroxazine, Blue) as a susceptible material was synthesized by condensing 1-nitroso-$\beta$-naphthol with indoline. The melting point of the synthesized spiroxazine dye was 254$^{\circ}C$. Irradiation with ultraviolet light had effect on reversible coloration reaction. The photochromic dye microcapsules were produced by in situ polymerization using urea-formaldehyde prepolymer. The average diameter of the microcapsule was 2.94$\mu$m. The dyeability and washing fastness of the photochromic microcapsule fibers were increased by the pretreatment of cationic agent.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.8
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• pp.771-779
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• 2001

In this study, a simulation program has been developed to predict the performance of a parallel flow condenser of an air conditioning system for an automobile. The well-known correlations for he heat transfer rates and the pressure drops are included in this model. It is fond that the numerical model can predict the heat transfer rate and the pressure drop accurately. As the condensing pressure increases of fixed air inlet temperature, the heat transfer rate increases and the pressure drop decreases. The effect of he degree of subcooling on the performance of the condenser is greater than that of the degree of super-heating because the ratio of the area occupied by he tow-phase refrigerant the total area is significantly affected by he degree of subcooling rather than the degree of superheating.

• International Journal of Air-Conditioning and Refrigeration
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• v.6
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• pp.67-79
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• 1998

This paper is about the performance of alternative refrigerants for low temperature and transport refrigeration chillers. A breadboard refrigeration chiller was constructed with counterflow heat exchangers. R502, its transitional alternatives of R402A and R402B, and long-term alternatives of R404A and R507 were tested in an attempt to compare the performance of each refrigerant against R502. Measurements were conducted at two condensing temperatures of 43.3$^{\circ}C$ and 52.$0^{\circ}C$ and the evaporating temperature was varied over a range from -$25^{\circ}C$ to -5$^{\circ}C$. The evaporator superheat and condenser subcooling were maintained constant at about 5$^{\circ}C$ for all tests. Test results showed that all alternative fluids tested in this work can be used as 'drop-in fluids' to replace R502 without any major problem. It is also found that in the long run HFC alternatives are to be used due to their favorable environmental characteristics and better performance.

• YAKHAK HOEJI
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• v.43 no.3
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• pp.316-319
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• 1999

Chrysin 7-Ο-crotonate was synthesized by condensing crotonic acid with chrysin in organic solvent, tetrahydrofuran (THF) using dicyclohexylcarbodiimide (DCC) and 4-dimethylaminopyridine (DMAP). Its structure was indentified by NMR, MS, UV, IR etc. We also investigated the physico-chemical properties and set up the quantitative anytical method of this compound. The correlation coefficient of calibration curve measured at the isobestic point (340 nm) on this compound was approximately 0.9994 by absorption spetrophtometry. Detection limit was 1.6ng at S/N=3 by using a RP column by HPLC. The hair growth effect fo chrysin 7-Ο-crotonate on the hair of black mouse (C57BL/6), was carried out using paste method. When its ethanol solution was administered to this black mouse by route of skin, this compound promoted the growth of hair.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.04a
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• pp.373-380
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• 1998

Generally the excessive caused by isolated sources in localized to members closely located to the vibration sources. In this case it may not be economical to model the whole structure to obtain the responses of a specific member. In this study, a substructuring technique has been used for local vibration of a framed structure. The boundary conditions of members selected are determined by condensing the degrees of freedom of the remaining members. Fixed and hinged boundary condition are also assumed for comparison. According to the results, the substructuring technique is quite efficient in predicting the responses of a structure on which the vibration source in located, but is not very reliable for the members located for away from the source.

• Journal of the Korean Chemical Society
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• v.62 no.5
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• pp.377-385
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• 2018

A new class of Chalcone-Sulphonamide hybrids has been designed by condensing appropriate sulphonamide scaffold with substituted chalcones tethered by chloroacetyl chloride as a multi-target drug for therapeutic treatment. Chalcones were prepared by Claisen-Schmidt condensation of a substituted aldehyde with para aminoacetophenone. These Chalcone-Sulphonamide hybrids were screened by means of their antibacterial activity by NCCLS method. Among all these compounds, 5e and 5c displayed more potent growth inhibitory activity against Staphylococcus epidermidis and Pseudomonas aeruginosa bacteria respectively. Further, these hybrids were evaluated for their antifungal activity, among all hybrid 5a exhibited potent antifungal activity. The synthesized compounds were characterized by FT-IR, $^1HNMR$, $^{13}CNMR$ and HR-LCMS and spectral study supports the structures of synthesized Chalcone-Sulphonamide hybrids.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.547-552
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• 1998

The standard RELAP5/MOD3.2 code were assessed with the condensation experiment in the presence of noncondensable gas in a vortical tube of PCCS of CP-1300. There are two wall film condensation models, the default model and the alternative model, in RELAP5/MOD3.2. The experimental apparatus was modeled with the two models, md simulations were performed for several sub-tests to be compared with the experimental results. In overall sense the simulation results showed that the default model of RELAP5/MOD3.2 under-predicts the heat transfer coefficients, while the alternative model over-predicts them throughout the condensing tube.

• YAKHAK HOEJI
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• v.35 no.6
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• pp.483-485
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• 1991

A furanquinone substance(methyl 5-hydroxy-dinaphtho [1,2-2',3'] furan-7,12-dione-6-carboxylate) which has been isolated from the methanol extract of Paulownia tomentosa stem was synthesized by condensing 2,3-dichloro-1,4-naphthoquinone with methyl 1,4-dihydroxy-naphthalene-2-carboxylate in pyridine and identified by NMR, MS, UV, IR etc.