• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
• /
• pp.1247-1250
• /
• 2008

This presentation highlights work from the authors' laboratories on the various kinds of oxide optical materials, mainly luminescence and pigment materials with different forms (powder, core-shell structures, thin film and patterning) prepared by the Pechini-type sol-gel (PSG) process. The PSG process which uses the common metal salts (nitrates, acetates, chlorides etc) as precursors and citric acid (CA) as chelating ligands of metal ions and polyhydroxy alcohol (such as ethylene glycol or poly ethylene glycol) as cross-linking agent to form a polymeric resin on molecular level, allowing the preparation of many forms of luminescent materials.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 추계학술대회 논문집
• /
• pp.453-456
• /
• 2000

This paper presents experimental results on selecting optimal process parameters for UV-Vaccum casting. The UV-Vacuum casting is a relatively new process that allows very rapid mold preparation and part duplication via UV curing. Effect of various process variables such as pressure and temperature on mold strength and part accuracy was evaluated by using Taguchi method.

• Elastomers and Composites
• /
• 제42권2호
• /
• pp.86-92
• /
• 2007

이축 연신에 의한 폴리테트라플루오르에틸렌(PTFE) 막을 제조하기 위한 공정 조건을 확립하기 위하여 상용화되는 PTFE 막 및 PTFE 미세 분말을 선택하였다. 막 제조공정에 사용 되기 위해 PTFE 미세 분말은 전처리 되었고, 첨가제와 혼합되었으며, 혼합물의 숙성, 페이스트 압출 공정, 칼렌더 가공 공정 등이 수행되었고 막의 두께 및 기공크기와 다공성을 측정하였다. 기계적 물성을 강화하기 위하여 시료의 후처리가 실시되었고, PTFE 막 제조공정을 위한 페이스트 압출 공정에서의 PTFE 분말과 첨가제의 혼합비, 숙성 시간, 숙성 온도, 압력 등에 관한 공정 조건이 확립되었고, 기공크기(pore size)와 다공성(porosity)을 조절할 수 있는 이축연신 공정에 대한 최적공정 조건도 확립하였다.

• 한국조리학회지
• /
• 제13권2호
• /
• pp.201-215
• /
• 2007

This study was carried out to examine the sensory characteristics of Demi-glace sauce prepared by fresh basil with different amount of salt added. The evaluation of the sensory quality of Demi-glace sauce prepared by fresh basil was conducted by unexperienced and trained panel with regard to color, odor, taste, appearance, texture, viscosity, and overall acceptability while varying the quantity of salt added, the time of preparation, and the conditions of sauce offered in which each panel was supposed to evaluate both sauce itself and sauce with meat. It was found that Demi-glace sauce prepared by fresh basil with 0.3% salt added was gained the highest score from both panels in most properties and the second was the one with 0.1% salt added. In the sensory properties correlation analysis according to the time of preparation and the conditions of sauce offered, there was no significant correlation in most sensory properties for the unexperienced panel, except some significantly positive correlation between taste and overall acceptability of the sauce. Whereas there was a positive correlation in the majority of sensory properties for the trained panel regardless of the time of preparation and the conditions of sauce offered. The sauce with 0.3% salt added ranked as the best recipe by both panels among four different ratios of salt adding regardless of the time of preparation and the conditions of sauce offered. Triangle test showed that the sauce B with 0.1% salt added before the preparation was more highly appreciated in terms of taste than the sauce A with 0.1% salt added in the final step of preparation. In conclusion, it could be suggested that Demi-glace sauce prepared by fresh basil with 0.3% salt added is the best recipe for commercial products. Also, there seems to be the need of further sensory evaluation studies on the Demi-glace sauce according to the time of addition during the process of preparation.

• 한국세라믹학회지
• /
• 제29권4호
• /
• pp.253-258
• /
• 1992

ZnO varistors were prepared by the organochemical method which used citric acid and ethylene glycol as gelling agents. The microstructure of the sintered specimens exhibited small grains, uniform grain size distribution, and few intragranular pores. Thermal decomposition of the organic resin formed during the powder preparation process was completed around 450$^{\circ}C$. No significant changes were observed in microstructure and current voltage characteristic with respect to calcination temperatures. A major advantage of the organochemical method used in this experiment is a possible uniform mixing of trace amounts of dopants. Therefore, this powder preparation method seems promising in investigating the effect of Li or In ion, which is added in ppm level to ZnO varistors, on the pulse respose characteristic.

• 한국막학회:학술대회논문집
• /
• 한국막학회 1993년도 추계 총회 및 학술발표회
• /
• pp.7-12
• /
• 1993

Preparation of asymmetric polyimide membranes by the phase inversion process was investigated to develop ultrafiltration, reverse osmosis and pervaporation membranes for organic solutions, using a commercially available solvent-soluble polymaide. The influences of the various factors such as the composition of a cast solution, casting conditions, gelating solutions and others on membrane structure and performance were studied in detail, and it was made clear that a wide variety of asymmetric polyimide membranes ranging from UF to RO for organic solutions could be prepared from the aromatic polyimide used. It was also found that the chemical stability and separation performance of the asymmetric polyimide membranes could be improved by annealing in a liquid or a vacuum at above 200$\circ$. The membrane annealed at 300$\circ$ in a vacuum exhibited the separation factor $\alpha(H_2O/EtOH)$ of 900 with the flux of 1.0 kg/$m^2\cdot h$ at 60$\circ$C for an aqueous ethanol solution of 95 vol%.

• Journal of the Korean Wood Science and Technology
• /
• 제21권1호
• /
• pp.59-64
• /
• 1993

The purpose of this study is to investigate the preparation of the carboxymethylcellulose from recycled fiber, especially on the reactivity of carboxymethylation. Using a deinked pulp and a dissolving pulp. Green's method is adapted to the carboxymethylation. We conformed that the carboxymethyl group is led for recycled fiber by FT-IR analysis. The recycled fiber is more reactive than the dissolving pulp because the recycled fiber had been defiberated and pretreated with alkali. It suggests that deinking process is in accordance with pretreatment of CMC process. Therefore, it may be possible to prepare CMC from the recylced fiber economically.

• 한국환경과학회지
• /
• 제13권3호
• /
• pp.319-325
• /
• 2004

An experimental study on the preparation of monolithic porous polymers by environmentally friend process in supercritical carbon dioxide has been carried out. Polymerization mixture composed of a cross-linking monomer, initiator and functional co-polymer was charged in the reactor with sapphire window. After the system was purged with a flow of $CO_2$ for 15 min, the reactor was pressurized with liquid $CO_2$ up to 100 bars. The reactor was isolated from and placed back to the system via quick connector for shaking until the mixture had become fully homogeneous. The reactor was then heated and pressurized to the required reaction conditions and left overnight. After cooling and $CO_2$ evacuation, the polymer was removed from the reactor as dry, white, continuous monoliths. The effect of experimental conditions on the physical properties of porous polymer was systematically examined, and it was found that monomer content had a major effect on the physical properties of the polymers.

• 한국결정성장학회지
• /
• 제8권2호
• /
• pp.370-376
• /
• 1998

분무열분해된 전구체로부터 수열반응에 의해 분말 Zinc-Silicate 형광물질 합성에 대하여 연구하였다. 열분해 전구체를 사용한 수열반응의 특징은 고상반응에서의 분쇄시의 불순물의 함유를 배제하였으며, $250^{\circ}C$의 수열반응에 의해 $\alpha-Zn_2SiO_4$ 분말합성이 가능하였다.

• 안보군사학연구
• /
• 통권13호
• /
• pp.109-136
• /
• 2016

Define the importance and role of the acquisition strategy based on the Defense Acquisition Management System, diagnose and analyze the actual state of document preparation. We analyzed the timing and details of the basic strategy of the project in 2015 and suggested a supplementary plan to improve the efficiency of Military force improvement projects in conjunction with the Defense Planning and Management System. It is necessary to reduce the preparation period including the policy decision making process and then divide it into planning and programming stages to complement the role of acquisition strategy. In order to apply these improvements, the necessary revision of laws and regulations to be reviewed is referred to, enabling continuous research.