• Progress in Superconductivity and Cryogenics
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• v.8 no.1
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• pp.23-25
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• 2006

Optimization of process variables, including oxygen and water partial pressure and also an nesting temperature, was performed in batch-type process to fabricate YBCO films on LaAlO3 single crystal. In this work, YBCO oxide powder was used as a starting precursor for metal-organic deposition(MOD)method. The precursor films were fabricated in batch furnace and they were converted to the epitaxial YBCO films at the same furnace with varying the process variables. The oxygen partial pressure was varied from 100ppm to 2000ppm and the water partial pressure from 1.2% to 12.2%. The window for optimal P(O2) was narrow about 700ppm for batch-type process. YBCO films in bathc-thype MOD process were optimized at 740-770oC and P(H2O) of 2.3%-7.3%.

• Journal of the Korea Organic Resources Recycling Association
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• v.13 no.1
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• pp.61-70
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• 2005

In order to reduce salt(as NaCl) contents in food waste and to improve the quality of discharged wastewater produced during the recycling process of food waste for the purpose of compost and feed stuff, a salt reduction process by added water into food waste was developed. The pilot plant with a rotary type salt reduction equipment to manage continuously 0.5 ton food waste per hour was constructed and the efficiency was tested. The amount of added water was calculated by the water content and the efficiency of dewatering process of food waste. Approximately 0.8 liter water per a kilogram of food waste was injected into the reactor in which food waste was pouring simultaneously, then diluted/mixed in a rotary reactor. About 1.1 liter of leachate including added water was generated, but the leachate contained a very high content of organic particles, so most particles were recovered by two step solid-liquid separation process. The first step was a gravitational filtering process using screens with a pore diameter of 1mm, and the second separation process was centrifugal process. Organic quality of food waste which had been desalted was maintained by inputting the entirely recovered organic particles. The efficiency of salt reduction of food waste was estimated by measuring a chloride anion by titration and salinity by a probe. The results by the two different measuring methods were always over 50%, and the quality of final wastewater was improved up to $200mg/{\ell}$ as TS(total solid) by an additional settling process after the two step solid-liquid separation process.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.8
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• pp.2073-2080
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• 1994

In this paper, a model of material removal in abrasive water jet machining of brittle material is developed, and experimentally evaluated. Abrasive water jet machining proved to yield better material removal rate than other machining techniques for hard and brittle material (alumina ceramics). It was also found that large scale fracture may develop at the exit of the jet from the material. The fracture size was predicted as a function of water jet pressure and size of the hole. Finally, the feasibility of using acoustic emission signals for in-process monitoring of the abrasive water jet machining process is investigated.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.12-17
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• 2006

Natural rivers have water purification functions called Gravel Contact Oxidation Process, which decontaminate river water by biological absorption, oxidation and degradation on riverbed gravels. This function has been developed and applied to many small/medium-sized urban rivers in Japan as one of the direct river water purification methods. However the method hasn't been verified in the tropics, which have different climate conditions and river characteristics. A preliminary experiment carried out at a polluted urban tributary in the outskirts of Kuala Lumpur, Malaysia where an increasing attention has been paid to river environment, showed a good applicability to the tropical conditions as a technically practical water purification measure with some maintenance cares for sludge management.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.15-18
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• 2007

This study investigated disinfection effect by general water purifier and water purifier with UV light disinfection. The results are as follows : (i) The general bacteria existed plentifully in a storage tank before treatment (ii) Water treated in water purifier did not meet the water treatment regulation standard since the presence of bacteria, whereas with UV light application the regulation standard is totally satisfied. (iii) Photocatalytic disinfection process with UV light in the presence of $TiO_2$ more effectively killed general bacteria than UV light only.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.5
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• pp.420-425
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• 2000

Crosslinked polyethlyene/silane crosslinked polyethylene(XLPE/SXLPE) blends were prepared by a twin screw extruder and their water tree growing electrical breakdown and crossinking characteristics were investigated. The water tree characteristics of XLPE were improved by the addition of SXLPE when samples were crosslinked only by the thermorolysis of DCP (dicumyl peroxide). However steam curing process was not good for water tree characteristics. It was also found that the rate of water tree growing of XLPE/SXLPE blend increased when the content of SXLPE was 50%. AC breadown strength slightly increaed by the addition of SXLPE to XLPE when samples were crosslinked only by the thermorolysis of DCP. It was also found that the degree of crosslinking of XLPE/SXLPE blends were higher than that of XLPE in the case of the content without steam crosslinking process.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1139-1145
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• 2008

Bread is an essential food consumed worldwide. Bread rapidly loses its desirable texture and flavor qualities associated with freshness through a process known as staling. The shelf life of bread is limited by this staling leading to economical losses in the range of one billion dollars per year. There are a number of mechanisms thought to be related to the staling process, such as water migration and redistribution, starch retrogradation, and gluten transformation. In this review, roles of water and water migration on bread staling are summarized and discussed.

• Journal of the Semiconductor & Display Technology
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• v.18 no.4
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• pp.124-128
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• 2019

In this paper, a high temperature plastic film type water level sensor was developed. The high temperature film type water level sensor was manufactured by attaching a copper film to a polyimide film which can be used for a long time at 250℃, by laminating process and patterning the electrode by etching process. For the performance evaluation of the developed film type water level sensor, the temperature dependence of the capacitance was measured, and the deformation was examined after standing for 8 hours in 150℃ air. The developed film type water level sensor can be used at up to 150℃, and can be applied to electric ports and steam devices.

• 전기의세계
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• v.25 no.6
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• pp.8-13
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• 1976

The industrial processes have become complicated on a large scale bacause of improvement of productivity, research of efficiency, and shortage of locations to be suited for foundation of factories. Consequently, the instrumentation and control systems for operating these industrial processes have also been highly improved with the development of mass information means. In order to operate these large-sized and complicated industrial processes safely, the man-machine interface for correspondence between man and machines and the instrumentation system regarding process fault processing are playing an important role increasingly. This paper describes recent instrumentation system in the water purifying plant as an example of these industrial processes, and covers both man-machine interface and process fault processing. The annual water supply quantity and diffusion were 2, 000, 000, 000m$^{3}$ and 25.0% in 1950 inJapan, but they amounted to 12, 000, 000, 000m$^{3}$ and 86.7% in 1974, respectively. The demands of water will increase incessantly, while it becomes gradually difficult to secure water sources. Accordingly, local self-governing bodies such as municipal cooperation, towns, and villages often construct a large-scale water purifying plant at one place in common, as required, without constructing respective plants independently. It is an absolute requirement for the water purifying plant to avoid stopping water supply to fullfil its social responsibility from the viewpoints of its public utility enterprise, and also it has gradually become difficult to secure skilled operators enough to cover such water purifying plants that are additionally provided in various districts. Thus, the importance of the man-machine interface for assuring safety operation of the water purifying plant irrespective of unskillfulness of operators as well as the instrumentation system regarding process fault processing, or, safety instrumentation, is more and more increasing as the water purifying plants are on a large scale.

• Journal of Korean Society on Water Environment
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• v.18 no.3
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• pp.327-336
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• 2002

Disinfection process in water treatment plants (WTPs) is one of the most important step in order to inactivate waterborne disease. However, what is the necessary disinfection in WTPs was not properly established in Korea. This study was conducted to evaluate disinfection performance in nationwide water treatment plants (n=474). Disinfection requirement based on the SWTR (Surface Water Treatment Rule) of the U.S. (1-log Giardia removal) was chosen in estimating the compliance. The scope of unit process for evaluating disinfection performance includes postdisinfection process in clearwells, pipeline, and storage tank. The worst water quality condition in individual WTPs was applied for the disinfection performance evaluation. The major results are as follows. First, it was appeared that 184 WTPs (39 %) provided insufficient disinfection performance. Disinfection performance was significantly improved during past 2 years. The ratio of the number of WTPs providing insufficient disinfection performance in 1999 and 2001 was 78 % and 41 %, respectively. One of major factors for this improvement was due to the improvement of $T_{10}/T$ value in clearwell, as a result of modification of clearwell facility. Second, if disinfection criteria is 3-log Giardia inactivation at worst water quality condition, then 19 % of all WTPs can not meet this disinfection criteria. And if disinfection criteria is strengthened to 4-log Giardia inactivation, then 58 % of all WTPs can not meet this disinfection criteria. Since disinfection criteria is decided by contamination level of Giardia in source water, it also needs the investigation of Giardia occurrence in source water.