The preparation of CaSO4 nanoparticle by vesicles formed spontaneously in cationic OTAC and anionic ADS mixed surfactant solution whose ratio is 0.3/0.7 is investigated. Added electrolytes for preparing nanoparticles reduce vesicle size about 200-300 nm comparing with that of pure vesicle whose size is 700-800 nm by DLS. The core of vesicles has 200 nm size and acts as nanoreactors which same size of monodisperse CaSO4 nanopaticles are formed. Although CaSO4 particles are formed at the outer of vesicles, they are very large and amorphous. The formed particles are identified with XRD analysis after separation due to coinciding with CaSO4 particles.

Highly crosslinked micron-size monodispersed PMMA/PDVB and PS/PDVB particles were prepared using seeded multi-stage emulsion polymerization. PMMA and PS seed particles were synthesized by seeded multi-stage emulsion polymerization and soap-free emulsion polymerization. Then PMMA/PDVB and PS/PDVB particles were obtained using semi-batch type emulsion polymerized using divinyl benzene as a cross-linkable monomer in the presence of seed particles. PMMA particles with size of ca. 730 nm and polydispersity of 1.03 were successfully prepared in this experiment. PS particles with size of ca. 1.5 μm and polydispersity of 1.01 were prepared in this experiment. Highly crosslinked PS/PDVB particles with size of ca. 1.3 μm and polydispersity of 1.00 were obtained.

Reaction conditions and catalysts were investigated for direct CF3I synthesis. Optimum reaction temperature was determined by pyrolysis of CF3H and catalytic reactions. Reactions with changing oxygen concentration were performed. As a result, yield of CF3I increased with decreasing oxygen concentration. Catalytic activity was changed with the weight ratio of the used metal salts. This result was stemmed from the change in the pore size of activated carbon by the metal salts. The optimum reaction conditions were: 600℃, space velocity of 45hr-1, and with 7wt% KF/AC catalyst.

본 연구에서는 ionomer와 여러 가지의 유기화물로 처리된 MMT type의 clay를 이용하여 ionomer-clay 하이브리드 막을 용융삽입법으로 제조하였다. Twin extruder를 사용하여 clay를 ionomer에 분산시켰으며, 제조된 ionomer-clay 하이브리드에서 clay의 특성피크가 완전히 박리되거나 이동하는 XRD 결과로부터 clay의 층간거리가 넓어지는 고분자의 clay 층간삽입을 확인하였다. Clay의 종류에 따라서 제조된 ionomer-clay 하이브리드 막의 가스투과도, 기계적 물성 및 열적 성질을 측정하였다. ionomer-clay 하이브리드 막은 clay 자체의 도입과 층간거리의 확대로 기체분자의 tortuosity를 증가시켜서 가스투과도를 저하시키는 것을 확인하였다.

An acid cleaning agent (AACA) for aluminum was prepared by blending of sorbitol, n-octanoic acid, MJU-100A, Tetronix T-701, PPA-23, C8-83 and phosphoric acid. With the prepared AACA, degreasing, foam height, etching and derusting tests were carried out. As a result, AACA-4 and AACA-7 showed better cleaning ability than commercial acid cleaning agents.

The injection mold industry has strong relationship with many other industries. In the injection mold industry, the harmonious collaboration of the order-making companies, the mold-making companies, and the molded-parts making companies, which are distantly located, is very important. In this study, a web-based collaboration system is developed for the purpose. It offers the criterion to select appropriate production companies. It also tries to minimize the production cost of the mold design by distributing and evaluating the design information. The developed system is constructed using various recent web-programming tools.

This research considers the problem of scheduling Jobs on unrelated parallel machines with a common due date The objective is to minimize the total absolute deviation of Job completion times about the common due date. This problem is motivated by the fact

What is the most important in articles of food is hygienic safety. Because food Is the most common thing in our everyday life, however, the importance of its hygienic safety and other many problems caused by food may be easily neglected. What is more, food is can be dangerous as much as it is directly related to human life and accidents from the same cause may have different effects on the victims according to physical and environmental differences of individuals. Thus PL action for food requires more thorough prevention and measure. Korea has been enforcing 'the Product Liability Act' since the 1<SUP>1st</SUP> of July 2002. Product Liability (PL) is liability of the manufacturer or the seller of a product to compensate for the death or injury of consumers or the loss of properties caused by the defect of the product. This study surveyed consumers' response to and the effects of the enforcement of the Product Liability Act, investigated how consumers perceived the importance of food safety and the risk of defective food based on PL standards and their experience in damage by food through a questionnaire survey, and analyzed collected data through empirical analyses (reliability analysis, factorial analysis, regression analysis and ANOVA t-test) using SPSS 10.0. Based on the results of analysis, the researcher proposed strategies for coping with the Product Liability Act in the food industry

Nano sized FeAl intermetallic particles were successfully synthesized by plasma arc discharge pro-cess. The synthesized powders shouted core-shell structures with the particle size of 10-20 nm. The core was metallic FeAl and shell was composed of amorphous Because of the difference of Fe and Al vapor pressure during synthesis, the Al contents in the nanoparticles depended on the Al contents of master alloy.

Fe(C) nanocapsules were prepared by the chemical vapor condensation(CVC) process using the pyrolysis of iron Their characterizations were studied by means of X-ray diffraction, X-ray photoelectron spectrometer and transmission electron microscopy. The long-chained Fe(C) nanocapsules hav-ing the mean size of under 70 nm could be obtained below in different gas flow rates. The particle size of the powders was increased with increasing decomposition temperature, but it was decreased with increasing CO gas flow rate. The Fe powders produced at consisted of three layers of phases, but it had two phase core-shell structure which consited of phase of core and graphite of shell at

Iron-carbon nanocapsules were synthesized by plasma arc discharge (PAD) process under various atmosphere of methane, argon and hydrogen gas. Characterization and surface properties were investigated by means of HRTEM, XRD, XPS and Mossbauer spectroscopy. Fe nanocapsules synthesized were composed of three phases with core/shell structures. The surface of nanocapsules was covered by the shell of graphite phase in the thickness of nm.

Dispersion stabilities and photocatalytic activities of rutile powders with unique nano-structure synthesized by homogeneous precipitation process at low temperature(HPPLT) have been investigated in the acrylic resin containing fluorostyrene in the range of mole. Isoelectric point of in the acrylic resin placed in the neutral region whereas that of in the water placed in the acidic region, indicating that zeta potential and agglomeration of powder is strongly dependent on the pH and the type of solvent. To prepare an adhesion, an acrylic resin containing fluorostyrene was synthesized by a radical polymerization. The adhesion of coating layer was increased with increasing fluorostyrene's contents without changing the dispersion stabilities and degrading photocatalytic properties

In this study, nano-sized indium oxide powder with the average particle size below 100 nm is fab-ricated from the indium chloride solution by the spray pyrolysis process. The effects of the reaction temperature, the concentration of raw material solution and the inlet speed of solution on the properties of powder were studied. As the reaction temperature increased from 850 to , the average particle size of produced powder increased from 30 to 100 nm, and microstructure became more solid, the particle size distribution was more irregular, the intensity of a XRD peak increased and specific surface area decreased. As the indium concentration of the raw material solution increased from 40 to 350 g/l, the average particle size of the powder gradually increased from 20 to 60 nm, yet the particle size distribution appeared more irregular, the intensity of a XRD peak increased and spe-cific surface area decreased. As the inlet speed of solution increased from 2 to 5 cc/min., the average particle size of the powder decreased and the particle size distribution became more homogeneous. In case of the inlet speed of 10 cc/min, the average particle size was larger and the particle size distribution was much irregular compared with the inlet speed of 5 cc/min. As the inlet speed of solution was 50 cc/min, the average particle size was smaller and microstructure of the powder was less solid compared with the inlet speed of 10 cc/min. The intensity of a XRD peak and the variation of specific area of the powder had the same tendency with the variation of the average par-ticle size.

The Fe-Ni compact bodies were fabricated using Fe-Ni mixed powders with 50 nm in diameter by injection molding process. The relationship between microstructure and material properties was characterized with respect to the volume ratio of powder/binder and sintering temperature with SEM and TEM. In the compact body having the volume percent ratio of 45(Fe-Ni) : 55(binder), which was sintered at the values of relative density and hardness were low about and 277.1 Hv, respectively. Using the composition of 50(Fe Ni) : 50(binder) and sintered at the values of relative density and hardness were respec-tively. The grain size of sintered bodies strongly depended on the sintering temperature. In both samples sintered at the average grain sizes were about 150 nm and 500 nm in diameter, respectively.

The bi-materials composed of and its composite reinforced with SiC particles were prepared by ball-milling and subsequent sintering process. The size of powder in Al-Mg/SiCp mixture decreased with increasing ball-milling time, it was saturated above 30 h when the ball and powder was in the ratio of 30 to 1. Both powders mixture and mixture were compacted under a pressure of 350MPa and were bonded by sintering at temperatures ranging from 873K to 1173K for 1-5h. At 873k, the sound bi-mate-rials could not be obtained. In contrast, the bi-materials with the macroscopically well-bonded interface were obtained at higher temperatures than 873K. The length of well-bonded interface became longer with increasing temperature and time, indicating the improved contact in the interface between unreinforced Al-Mg part and Al-Mg/SiCp composite part. The relative density in the bi-materials increased as the sintering temperature and time increased, and the bi-materials sintered at 1173K for 5h showed the highest density.