• 한국공작기계학회논문집
• /
• 제15권3호
• /
• pp.111-119
• /
• 2006

The ultra-precision stage is demanded for some industrial fields such as semiconductor lithography, ultra-precision machining, and fabrication of nano structure. A new stage was developed for those applications in order to obtain nano meter resolution. This stage consists of symmetric double parallelogram mechanism using flexure hinges. The mechanical properties such as strength of the flexures and deformations along the applied force were analyzed using FEM. The stage is actuated by a piezoelectric actuator and its movement was measured by a ultra-precision linear encoder. In order to improve positioning performance, a PID controller was designed based on the identified second order transfer function. Experimental results showed that this stage could be positioned within below 5 nm resolution irrespective of hysteresis and creep by the controller.

• 한국산업융합학회 논문집
• /
• 제8권1호
• /
• pp.5-10
• /
• 2005

PCL were intercalated into organically modified MMT (PCL-MMT) at $80^{\circ}C$ for 4hrs to prepare the PCL-MMT nanocomposite. PCL-MMT and PCL were mixed mechanically with two-roll mill at $150^{\circ}C$ for 15mins. From the results of XRD and TEM, it were found that PCL-MMT nanocomposite were prepared. And mechanical properties and biodegradation of nanocomposite have been investigated by tensile meter and biodegradability analysis experiment. Because of MMT dispersed homogeneously in PCL matrix, the Young's modulus of the nanocomposite was found to be excellent. But the tensile strength and elongation were decreased as increase of MMT. And MMT dispersed in PCL matrix was almost not affected on the biodegradation of PCL.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 1993년도 추계학술발표회논문집
• /
• pp.97-102
• /
• 1993

The application of epxy composite materials for the outdoor insulating systems has some significant advan-tages compared with conventional inorganic materials, that is low weight in combination with high mechanical strength, small dimensions and design versatility. The paper describes the results of high voltage investigations carried out different aging types of epoxy resin insulator and silicone grease coating. The insulators have been exposed 3000 hours to weather-o-meter and 12 months to outdoor. In this connection, the main study of paper is form the basis of develop-ment of principal technologies of epoxy composites which ard: (1)manufacturing of insulator, (2)high vol-tage testing under dry and wet condition, (3)mechani-cal properties, (4)accelerated weather-ometer test and outdoor exposed, artificial polution.

• Elastomers and Composites
• /
• 제29권2호
• /
• pp.113-120
• /
• 1994

The vulcanization characteristics, physical and electrical properties have been measured for magnetite-loaded CM compounds containing various concentration of magnetite. Samples of the various concentration of magnetite are characterized by oscillating disk rheometer, mooney viscometer, tensometer and resistance meter. The morphology and dispersion of magnetite are analyzed by scanning electron microscope(SEM). The results obtained are as follows : 1. The CM compound without magnetite shows plain curve, while the CM compounds containing magnetite show short curves. 2. The maximum volume of magnetite is 600 phr in the CM compounds. The magnetite of 30 to 150 phr of magnetite act as reinforcement agents and the 50 phr magnetite shows maximum tensile strength. 3. The electric conductivity is mostly influenced by the conditions of temperature, compacting pressure, and magnetite orientation. Further efforts should be made to develop a new design in various electric conductivity fillers for the most efficient and applicable rubber products.

• 동아시아식생활학회지
• /
• 제24권6호
• /
• pp.837-844
• /
• 2014

This study was conducted to promote the utilization of fish paste containing loquat leaf powder (LLP). The tested concentrations of LLP were 0, 3, 5 and 7%. The pH of samples ranged from 6.75 to 6.89, and moisture content ranged from 75.23 to 76.95%. The L values of samples decreased as the concentrations of LLP decreased, and a and b values increased. In the folding test, all test samples with AA showed good flexibility. In the texture meter test, hardness, strength, springiness, gumminess and chewiness increased according to increasing concentrations of LLP. In the sensory evaluation, fish paste prepared with 5% LLP was preferred over other fish pastes. These results suggest that LLP can be applied to fish paste for the purpose of high quality and functionality.

• Bulletin of the Korean Chemical Society
• /
• 제30권10호
• /
• pp.2203-2207
• /
• 2009

Chemical equilbria of nickel chloride in HCl solution at $25\;{^{\circ}C}$ were analyzed by considering chemical equilibria, mass and charge balance equations. The activity coefficients of solutes were calculated by using Bromley equation. The necessary thermodynamic properties, such as the equilibrium constant for the formation of Ni$Cl^+$ at zero ionic strength and interaction parameter, were evaluated by applying Bromley equation to the stability constant data reported in the literature. It was found that most nickel exists as $Ni^{2+}$ in HCl solution up to 5 molality HCl. The pH values of Ni$Cl_2-HCl-H_2O$ system at $25\;{^{\circ}C}$ calculated in this study agreed well with the pH values measured by employing pH meter.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
• /
• pp.1248-1251
• /
• 2000

Recently, the yearly amount of remicon used in Korea is approximately one hundred million cubic meter, and it caused a by-product, remicon waste sludge. The sludge produced by washing mixers or drums of remicon trucks is restrained by the law for waste disposal because its pH is over 12, so the expense for waste disposal is needed. Until now, the waste sludge water has been recycled and used for concrete materials as sludge water which is limited to 3% of cement unit weight. However, the study on the properties of the concrete mixed with this waste sludge is so insufficient that the quality of them can be hardly trusted. Therefore, the study on that will be discussed.

• 대한안전경영과학회지
• /
• 제4권2호
• /
• pp.1-10
• /
• 2002

In order to protect the head, baseball helmet must to have proper strength and to absorb the kinetic energy. The purposes of this study are to validate whether the helmet have the protecting ability or not. We performed three kinds of experiment to know about the this ability. To find out the limit of displacement at 4 points(front, rear, right side, and left side), the static load by magnetic dial gauges were used, and to validate the ability of absorption, drop tests were peformed from 0.5 and 1.0 meter. Futhermore, we calculated natural frequency of the helmets by the principle of Lissajous Diagram and we performed FEM(Finite Element Method) analysis. From the results of these experiments, we found that the displacement of helmet was largest at rear point and it was smallest at left-side point(ear-covered part). The ability of absorption was better at the left-side point than the other points.

• 국제초고층학회논문집
• /
• 제4권3호
• /
• pp.199-207
• /
• 2015

Abeno Harukas is the tallest building in Japan and is located in Abeno, which is one of the three main railway transport nodes in Osaka. This building has a height of 300 meters, and its lowest levels are 30 meters below ground. It contains a department store, museum, offices, a hotel, and an observatory. In this urban renewal project, a section of the department store that encloses the station was dismantled and replaced by a supertall building complex, while infrastructure was simultaneously constructed, including: upgrades to the station and the existing department store, improved connections to the subway and pedestrian bridges, and a new pedestrian walkway over the road. In this paper, the ingenious erection processes, newly developed technologies, and precise construction management techniques are introduced for Japan's tallest building.

• 한국식생활문화학회지
• /
• 제28권6호
• /
• pp.657-663
• /
• 2013

This study analyzed fish paste containing Lagocephalus lunaris powder (LLP). The moisture, crude ash, crude protein, and crude lipid content of LLP were 6.21%, 1.03%, 74.50%, and 1.21% respectively. The tested concentrations of LLP were 0, 3, 5, and 7%. The pH of the samples ranged from 6.75 to 6.89, and moisture content ranged from 75.23% to 76.95%. The L values of the samples decreased as the concentrations of LLP decreased, and the a and b values increased. In addition, the folding test results in all test samples were "AA", indicating a good mean flexibility. In the texture meter test, the hardness, strength, springiness, gumminess, and chewiness increased according to increasing concentrations of LLP. In the sensory evaluation, the fish paste prepared with 5% LLP were preferred over other fish pastes. These results suggest that LLP can be applied to fish paste for substantially increasing its quality and functionality.