• The Journal of the Petrological Society of Korea
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• v.9 no.4
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• pp.205-210
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• 2000

Measurements of phase identification and degree of orientation for fine-grained (about 0.3 mm in diameter) minerals in rock samples performed by micro-area X-ray diffractometer.$Al_{2}SiO_{5}$ polymorphs (andalusite, kyanite and sillimanite) were chosen for the measurements and target minerals were existed on thin sections. Micro-area X-ray diffractometer is composed of 3(${\omega}\;{\chi}\;{\phi}$)-circle oscillating goniometer and position sensitive proportional counter (PSPC). $CuK_{\alpha}$ radiation was used as X-ray source and a pin hole ($50\;\mu\textrm{m}$$ in diameter) collimator was selected to focus radiation X-ray onto the target minerals. Phase identification and diffracted X-ray peak indexing were carried out by 3(${\omega}\;{\chi}\;{\phi}$)-circle oscillation measurement. Then, 2(${\omega}\;{\phi}$)-circle oscillation measurement was made for the purpose of searching the prevailing lattice plane of the minerals on thin section surface. Finally, for a selected peak by 2-circle oscillation measurement, X-ray pole figure measurement was executed for the purpose of check the degree of orientation of the single lattice direction and examine its pole distribution. As a result of 3-circle oscillation measurement, it was possible that phase identification among $Al_{2}SiO_{5}$ polymorphs. And from the results of 2-circle oscillation measurement and X-ray pole figure measurement, we recognized that poles of andalusite (122), kyanite (200) and sillimanite (310) lattice plances were well developed with direction normal to each mineral surface plane respectively. Therfore, the measurements used with micro-area X-ray diffractometer in this study will be a useful tool of phase identification and degree of orientation measurement for fine-grained rock forming minerals.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.613-618
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• 1999

This paper discuss the chemical, physical and mineral properties of classified fly ashes by electrostatic precipitator and calcinated fly ashes at 50$0^{\circ}C$. The electrostatic precipitator in coal fired power plant has a number of hopper in the direction of flue gases. The properties of fly ashes collected at each hopper in the electrostatic precipitator are different. Superfine, fine and ordinary fly ashes can be collected respectively at each hopper. The carbon content in fly ash is influenced on the viscosity of paste. By calcination, the carbon content in fly ash is decreased and the fluidity of paste is improved.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.3
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• pp.125-132
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• 2022

The Ministry of Environment recently analyzed the output data of 10 fine dust measuring stations and, as a result, announced that about 60% had an error that the existing atmospheric measurement concentration was higher. In order to accurately predict fine dust, the wind direction and measurement position must be corrected. In this paper, in order to solve these problems, fuzzy rules are used to solve these problems. In addition, in order to calculate the fine particulate sensation index actually felt by pedestrians on the street, a computer simulation experiment was conducted to calculate the fine particulate sensation index in consideration of weather conditions, temperature conditions, humidity conditions, and wind conditions.

• Journal of Sericultural and Entomological Science
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• v.39 no.2
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• pp.186-196
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• 1997

The IR crystallinity index of Calcium nitrate treated silk fiber decreased proportionally to the concentration of calcium nitrate. A partial change of conformation was observed in the concentration of over 46.4-47.6% changing from $\beta$-sheet or to random coil in the crystalline region. This is in coincidence with the result of crystallinity index, which was started to be reduced in the concentration range of 46.4-47.6%. A same trend was observed for the X-ray order factor, birefringence, degree of orientation and surface structure. These structural parameters were remarkably changed on the treatment of silk fibers with concentration of 46.4-17, 6% calcium nitrate. Therefore, it seems that there exists a critical concentration of calcium nitrate in affection the structure and morphology of silk fibers. According to the examination of surface morphology, the fine stripe was observed in the direction of fiber axis at 46.4% concentration. However, the treated concentration was exceeded by 47.6%, the cracks were appeared severely on the fiber surface in the transverse direction as well as fiber axis direction. This result might be related to the tensile properties, specially a tenacity of silk fibers. As a result of quantitative analysis of a dilute acid hydrolysis, three different regions, which are known as a amorphous, semi-crystalline and crystalline region, could be obtained. The hydrolysis rate curves were different with various concentrations of treatment and the relative contents of each region could be calculated.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.577-583
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• 2010

In this study, the effect of void formation resulting from gas hydrate dissociation or loss of some particles within soil structure on the strength of soil is examined. Beag-ma river sands with uniform gradation were used to simulate a gas hydrate bearing or washable soil structure. Empty capsules for medicine are used to mimic large voids, which are bigger than soil particle. Beag-ma river sand was miced with 8% cement ratio and 14% water content and compacted into a shear box. The number and direction embedded into a specimen. After 4 hours curing, a series of direct shear test is performed on the capsule embedded cemented sands. Shear strength of cemented sands with capsules depends on the volume and direction. The volume and direction formed by voids are most important factors in strength. A shear strength of a specimen with large voids decreases up to 39% of a specimen without void. The results of this study can be used to predict the strength degradation of gas hydrate bearing sediments after dissociation and loss of fine particles within soil structure.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.6
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• pp.867-874
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• 2010

RFID printing technology has emerged recently as an important tool for leading future IT. Therefore, many manufacturers concerning on low cost and mass production of the related products pay close attention to the printing technology. In order to realize printed electronics, the technologies for fine line-width/gap printing and registration are essential work. This study proposes a precise Roll to Roll control system that is capable of tilting two posts. Two controllable tilting posts can adjust film position at traverse direction for the precision registration. A mathematical model for representing the geometric features of each posts in Roll to Roll printing system is established first. Then an operating program is built to implement the system and to control film movement. For experimental test, a hard ware system is fabricated which is consisted of two AC servo motors, two posts tilting mechanisms, several guide rolls, and so on. The test results show the proposed system can control the film position precisely at transverse direction.

• Particle and aerosol research
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• v.13 no.2
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• pp.43-52
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• 2017

Policy direction for the management of air quality in Korea has been on the reduction of the average concentrations of the criteria air pollutants such as sulfur dioxide and fine particles. However, recently, risk based management of air pollutants becomes an important issue. In this study, to develop an effective air quality management policy direction in Korea, (1) the fourth Multiple Air Toxics Exposure Study (MATES IV) carried out in the South Coast Air Quality Management District (SQAQMD) in the USA is reviewed and (2) the results are compared with in these in Seoul and (3) policy directions are suggested. It was found that (1) systematic integrated study comprising of measurement, modeling, emission inventory estimation, and risk assessment was essential to estimate the health risk of air pollutants reliably, (2) cancer risk of diesel particle was dominant over other air pollutants, and (3) health risk based emissions were different from amount based emissions. It was suggested that (1) reducing the exposure from hot spots might important to reduce health risk from air pollutants and (2) an integrated air quality management administration system is important for the efficient management of air pollution.

• Journal of Navigation and Port Research
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• v.46 no.3
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• pp.251-258
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• 2022

Donghae Port is adjacently located to a residential area wherein 26,933 generations are creating a living environment. The areas comprise Song-jeong village (5,754 generations) and Bukp-yeong village (21,179 generations). Major cargoes handled in Donghae Port are dusty limestone, cement, anthracite, and bituminous coal, etc. In the process of handling such cargoes, air pollutants including oxide dust and fine dust which adversely impact the living conditions and health of residents are generated, causing air pollution in the vicinity of the port. Currently, Donghae Port is making an effort to improve the operation environment of the infrastructure and equipment in stages, for the purpose of reducing air pollutant emissions caused by the port industries in a long-term perspective. In this study, the sphere of influence of fine dust exposure and the degree of air pollution in the surrounding area were analyzed such as the state of fine dust concentration and diffusion in the vicinity of Donghae Port, fine dust diffusion pattern and spatial distribution of high-concentration considering wind direction and speed characteristics during the day and seasonal cycles. A more effective plan to reduce the concentration of fine dust in nearby areas by combining reduction plan, is being developed in terms of improvement regarding port infrastructure and equipment, and reduction measures considering the characteristics of the atmosphere environment according to the daytime, nighttime and season.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.5
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• pp.73-79
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• 2021

This study was carried out to analyze the properties of the gel propellant and spray characteristics according to the addition of fine particles. The multi-hole diameter was 0.4 mm to induce a high shear rate, and a kerosene gel propellant was prepared using 5 wt% of the Thixatrol ST and SUS304 of 100 nm. The experiment was conducted by fixing the supply pressure in the axial direction to 0.7 MPa and adjusting the supply pressure in the radial direction from 0.7 MPa to 2.1 MPa. Due to the addition of fine particles, pressure vibration during spraying, a small TMR(Total Momentum Ratio) of up to 0.19, and a phenomenon that the spraying angle rapidly increased to more than 70 degrees occurred.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.343-345
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• 2002

The influence of starting precursor powders on the phase formation and transport properties of Bi-2223/Ag tapes has been studied. The experimental results show that the average particle size of precursors as fine as 1.64 ${\mu}{\textrm}{m}$ and 1.51 ${\mu}{\textrm}{m}$ can still increase the transport properties. The J$_{c}$-B behavior is also enhanced in tapes fabricated with powders in finer particle sizes. However, at higher magnetic fields, J$_{c}$ of tape started from the powder with the finest particles drops rapidly at the direction of H//c, which is possibly attributed to the small grain sizes and weak flux pinning ability that due to the short induction period at the initial stage of phase formation as the result of fine particles in precursor powder.der.