• Membrane Journal
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• v.34 no.2
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• pp.132-139
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• 2024

The ion exchange resin used to remove total dissolved solids (TDS) is used by being packed in a column, and sufficient contact time between the ionic material and the ion exchange resin is required during the ion exchange process. In this study, the ion exchange resin that exhibits high TDS reduction even with a short contact time through pulverization of the ion exchange resin was characterized. The optimal size of resin considering flowability was over 100 ㎛. The highest pulverizing yield were obtained that 250~500 ㎛ size and 100~250 ㎛ size were 67.3% and 36.9%, respectively. Also, the highest yield and the pulverizing time of 100~500 ㎛ size was 87.1% and 2 minutes, respectively. Under batch test conditions, the time to reach a removal rate of 95% and 99% for 250~500 ㎛ resins was 1.82 and 1.96 times faster than non-pulverized ion exchange resin, respectively. The 100~250 ㎛ resins showed 15.9 times and 6.18 times faster, respectively. Under the column test, a total of 1.74 g of NaCl was removed by non-pulverized ion exchange resins, 1.83 g of NaCl was removed by 250~500 ㎛ resins and 1.63 g of NaCl was removed by 100 and 250 ㎛ resins. As the size of the resin decreased, the capacity slightly decreased. As a result, it was observed that the pulverized ion exchange resins could be a method of achieving high TDS removal performance under short contact time.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.691-691
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• 2013

최근 휴대용 전자기기의 전원으로서 가장 널리 사용되고 있는 리튬 이차 전지는 우수한 에너지 밀도, 낮은 자가방전 속도로 인한 비 메모리 효과, 높은 작동전압으로 다양한 전자기기뿐만 아니라 미래형 자동차산업 및 항공산업 분야에서도 점차 사용 빈도가 증가하고 있다. 현재 리튬 이차 전지의 음극물질로 널리 사용되고 있는 흑연의 경우 초기 용량 감소가 크고 이론적인 최대용량(372 mAhg-1, LiC6)이 낮다는 문제가 있어 다양한 대체물질의 연구가 진행되고 있다. 그 중에서도 Si는 Li과 반응하여 Li4.4Si합금을 형성하며 높은 이론용량을 갖고 상용화된 전지의 전압(~3.7 V)보다 0.3 V정도 밖에 낮지 않기때문에 재료의 개발과 함께 바로 사용화 할 수 있다는 장점이 있다. 그러나 Si의 경우 금속 자체로 사용되는 경우 Li 이온이 삽입되어 Li4.4Si형성 시에 310%의 부피 팽창을 일으키게 되어 분쇄반응(pulverization)을 일으키고 충 방전에 따라 급격한 용량 감소를 야기한다. 본 연구에서는 이러한 문제점을 해결하기 위하여 RF 마그네트론 스퍼터링을 이용하여 보다 간단한 방법으로 Si층 사이에 수 나노의 Al층을 삽입하여 Si 입자의 부피 팽창으로부터 오는 응력을 상쇄시켜 높은 방전 용량 특성과 우수한 수명 특성을 동시에 구현하였다.

• 보존과학연구
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• s.29
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• pp.199-220
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• 2008

Hobun(Oyster shell White) is a traditional material used as extender and white pigment from ancient times. The production method of it, however, has been discontinued. We have studied the traditional production method of Hobun by weathering oyster shell, which is one of the traditional ways for preparing Hobun. Reproduction study of manufacturing method of the discontinued traditional material is an important accomplishment of our research. Also this study provides solid background knowledge to stabilize the production and supply of Hobun for the cultural asset repairing materials. The result can be summarized as follows: The production process of Hobun by weathering method takes 5 steps - (1) weathering shells ${\rightarrow}$ (2) washing ${\rightarrow}$ (3) pulverization ${\rightarrow}$ (4) separating fine powder by submerging in water ${\rightarrow}$ (5) drying. The major aim in step (1) is to eliminate organic impurities. In the step (4), the fine particles smaller than $25{\mu}m$ are separated by extracting the supernatant from stirred suspension after heavy particles are submerged. Also, the soluble inorganic impurities can be eliminated through the powder submerge in 15 times water and stirring the suspension 6 hours and changing the water 3~4 times. The final products have high quality with 94.03, 0.52, 2.05 for L, a, b, less than $25{\mu}m$ particle size, fine resistance for discoloration by light and environmental pollution and good workability.

• New & Renewable Energy
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• v.4 no.4
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• pp.37-43
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• 2008

Three properties of food waste are water 80%, ash 3%, volatile matter 17%. When food waste goes through treatment process such as removal of foreign substances, removal of water as well as sodium, dryness, and pulverization, it transforms into 4,000 Kcal/kg purverized fuel if moisture content is below 13%. Fuel ratio (fixed carbon/volatile matter) of purverized fuel is low compared with bituminuous coal. Ignition temperature measured by thermogravimetry analyzer is about $460^{\circ}C$. Combustion test of purverized fuel have been performed using energy recovery facility which include storage tank of dewatered cake, dryer, hammer mill, combuster including burner, boiler, flue gas treatment equipment. When 160-180 kg/hr of fuel is steadily supplied to burner for 3 hours, combustor temperature reaches about $1000^{\circ}C$ and CO is 77-103 ppm at 1.55 excess air ratio and SOx and Cl are under 2 ppm and 1ppm, respectively. This experiment demonstrate that purverized fuel made from food waste could be an alternative clean energy at the age of high oil price.

• Journal of Energy Engineering
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• v.23 no.4
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• pp.49-55
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• 2014

In this study, boiler tube thickness measurement and numerical analysis were conducted for standard 500MW coal-fired power plant in order to research the mechanism of tangential-fired boiler corrosion empirically. The most dominant corrosion mechanism of tangential-fired boiler waterwall was corrosion by sulfur contained in the unburned carbon. And the secondary mechanism was $H_2S$ gas corrosion at localized reducing atmosphere. It is required to decrease the air-stage combustion operation in order to mitigate the waterwall tube corrosion. Also stringent coal pulverization quality control and reinforcing work for corrosion susceptible area such as anti-corrosion coatings is required

• Journal of the Korean Ceramic Society
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• v.22 no.5
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• pp.47-53
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• 1985

In view of innovated utilization of Korean clay resources conventional techniques for pulverization are reviewed in comparison with fluid energy milling processes of fluidized-bed type. Throughout experiment indigenous halloysite ores (white grade) after usual pretreatment are employed as typical sample. It is evidenced that grinding by means of porcelain ball mills has limitation in reducing clay particles to less than 10${\mu}{\textrm}{m}$ in diameter regardless of whether it is processed in dry or wet. Upon use of tungsten carbide bull mill particulation to submicron sizes could be effected with relative ease but severe coloration in grey is attended indicating metallic contamination possibly from friction of the grinding apparatus itself. In contrast the modified fluid en ergy milling enables particulation to $\leq$10${\mu}{\textrm}{m}$ in diameter with simultaneous classification int olimited ranges of particle size distributions. Since this technique is in principle based on the interparticle collisions rather than on the frictions between particles and mill surfaces minimum impurity attendance would be an additional advantage. Evidence leads to the conclusion that the fluidized-bed type milling is regarded as highly effective in puverization as well as fractionation of the clay minerals under examination. This is especially so in contemplating high-value and/or high-purity clay products.

• The Korea Journal of Herbology
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• v.20 no.2
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• pp.17-26
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• 2005

Objectives : The study has been undertaken to scrutinize the results of Halloysitum Rubrum before and after physical and chemical manipulation. Methods : I used X-rays diffracted analysis system(Phillips X'Pert - MPD System) on condition of 40Kv, Anode of Cu Ka to grasp the compositions of crude Halloysitum Rubrums which have been from here and there after pulverization them below 200 mesh. X-rays fluorescence analysis system have been used to check the chief elements content of the ore on condition of 40Kv, 95mA. ICP-MS analysis system(Perkin Elmer, Elan 6100)have been used after a micro-elements and a heavy metals take advantage of mixed acid were dissolved completely. Results : The compositions of the ore Halloysitum Rubrum are composed of large amount of Halloysite and Kaolinite, and small amount of Hematite, Alum, quartzite. The chief elements content of the ore Halloysitum Rubrum are composed of Al and Si. A heavy metals in Halloysitum Rubrum are As, Cd, Cr, Cu, Pb, Zn, etc. As and Zn's amounts was lessen after physical and chemical manipulation Halloysitum Rubrum are decreased at $400^{\circ}C\;and\;450-500^{\circ}C$ each by heat analysis system. Conclusion : Results of this study show that Halloysitum Rubrum can be used in a diverse ways to treat many kinds of disease.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.160.2-160.2
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• 2014

Recently silicon has attracted intense interest as a promising anode material of lithium-ion batteries due to its extremely high capacity of 4200 mA/g (for Li4.2Si) that is much higher than 372 mAh/g (for LiC6) of graphite. However, it seriously suffers from large volume change (even up to 300%) of the electrode upon lithiation, leading to its pulverization or mechanical failure during lithiation/delithiation processes and the rapid capacity fading. To overcome this problem, Si nanowires have been considered. Use of such Si nanowires provides their facile relaxation during lithiation/delithiation without mechanical breaking. To design better Si electrodes, a study to unveil atomic-scale mechanisms involving the volume expansion and the phase transformation upon lithiation is critical. In order to investigate the lithiation mechanism in Si nanowires, we have developed a reactive force field (ReaxFF) for Si-Li systems based on density functional theory calculations. The ReaxFF method provides a highly transferable simulation method for atomistic scale simulation on chemical reactions at the nanosecond and nanometer scale. Molecular dynamics (MD) simulations with the ReaxFF reproduces well experimental anisotropic volume expansion of Si nanowires during lithiation and diffusion behaviors of lithium atoms, indicating that it would be definitely helpful to investigate lithiation mechanism of Si electrodes and then design new Si electrodes.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.722-727
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• 1996

A simple compost windrow-forming car and a compost tuner were developed at the aim of low cost manure management systems. The developed compost windrow- forming car is possible windrows formation at a short time. In order to be pulverized and mixed by upper and lower beaters at the windrow-forming, the condition of air and the mixing of materials to play a major role in composting is filled. This car can also utilized for a manure spreader by folding the windrow-forming cover. The developed compost turner is a type equipped with tractor rear-right side. Main specifications are 2.5m working width, overall length 3.3m and 45degrees conveyer inclination angle, 2 beaters for mixing and pulverization are equipped in front parts. Windrows of 2.5m width and 1.5m height are turned at the speed of 4.5-5.1m/min. In accordance with the above, by combining the compost windrow-forming car and the compost turner, a simple composting system for each farmer could be constructed by the low c st.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.6
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• pp.426-433
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• 2016

This paper investigates the effects of operating conditions of an air classifier mill (ACM) on the particle sizes of PVC and rice hull. Based on the Box-Behnken matrix, the pulverization experiments were performed considering three operating factors: the air flow rate, the classifier speed and the mill speed. The response surface methodology was applied to identify the effects of the operating factors on the particle size. Results show that the particle sizes are governed by the linear variations of the operating factors. As less air is supplied and the mill rotates more slowly, the powder of both PVC and rice hull becomes finer. Furthermore, the classifier speed has a significant effect on the PVC powder but almost no effect on the rice hull powder. Thus, it is found that strong interactions exist between the material characteristics of a particle and the operating conditions of the ACM.