• Journal of the Korean Wood Science and Technology
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• v.44 no.3
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• pp.457-476
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• 2016

This was investigated on the major issues and research trends regarding the heat-treatment of woods through literature reviews. The principal heat-treatment technologies utilized for industrial purposes include the Plato-process (Netherlands), the Retification process (France), the OHT-process (Germany), and the Thermowood Process (Finland). Factors that mainly influence the heat-treatment process are the wood species, process temperature, processing time, and the heating medium (air, steam, vacuum, N2, oil, etc.). Researches on investigating the optimal conditions with these process conditions being the variables stand as the mainstream. Heat-treated woods present dimensional stability improvement, but mass loss and strength reduction, a wide variations for decaying inhibition, and insufficient resistance against mold, wood borer, and termites. For further improvement in respects of durability or resistance to biological degradation, necessity to search for more suitable heat treatment process and processing conditions fit for each wood species has been suggested. Exploiting new ways to utilize heat-treated wood and extending its range of use have been considered to be important matters that need more effort put into for the sustainable and sound environment as well as saving the wood resources.

• Korean Journal of Microbiology
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• v.28 no.4
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• pp.351-363
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• 1990

A mutant was selected by NTG treatment of Mycobacterium sp. NRRL B-3805, which was capable of degrading plant sterol to androsta-4-ene-3, 17-dione and yields was higher than NRRL B-3805. Also this mutant produced androst-4-ene-3, 17-dione faster than NRRL B-3805. It described the mode of sitosteroidal degradation, and the interrelation between cell membrane and its attachment to substrate during the sterol degradation process by this mutant and it was compared with Mvcobacterium sp. NRRL B-3805.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.4
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• pp.342-350
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• 1991

This paper describes an adaptive beamformer which improves the frequency characteristics of the AMNOR system. The proposed beamformer uses a bank of filters to calculate the frequency degradation in each subband. In the process ofdesigning the beamformer, the filter coefficients are updated to minimize the power of the difference between a fictitious desired signal and the output under the permissible degradation value in each subband. Simulation results demonstrating the improved performances of the proposed method are presented.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.7 no.1
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• pp.25-30
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• 2001

The purpose of this study was to examine how can we keep the freshness of peeled chestnuts in distribution process. The 30 minutes impregnation treatment at the preservation solution of 0.3% consistency showed a good result. The solution treatment prevented from surface yellowing and quality degradation of peeled chestnuts. And, in vaccum packaging after treating chemicals surface drying was faster than the other packaging from 7th day. A vitamin C treatment was no effective to restrain the growth of microbials.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.3
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• pp.7-12
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• 2013

In Die casting process, the problem of die degradation is often issued. In oder to increase of die life the material degradation of die steel was investigated using test core pins. Three test core pins were positioned in front of the gate entry and observed washout and soldering resistance during Mg die casting process. The test parameters are set as different commercial die materials, coatings condition and hardness of die surface. Usign 220t magnesium die casting machine was employed to cast AZ91 magnesium alloys. After 150 shots, macroscopic observation of die surface was carried out. Additional 50 cycles later, test pins were chemically cleaned with 5% HCl aqueous solution to find out the existence of washout and soldering layers. Microstructural characterization of die surface and the die roughness measurement were performed together. Computational simulation using AnyCasting program was also beneficial to correlate the extent of die damage with the position of test pin inside die cavity. As results, the optimal combination of die steel with productive coating as well as its hardness was drawn out. it will be helpful to decide the material and condition considering increasing of tool life.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.270-273
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• 2001

Electrical tree is studied widely by manufacture state of insulating material fare and blazing fire diagnosis system of use in phenomenon of part discharge that happen for main cause of dielectric breakdown of equipment for electric power. Use process that draw tree pattern here measuring above zero to study special quality of this electricity tree, real-time processing by image processing is proposed because reproduction of tree blazing fire process drops and pattern of tree is difficult correct quantification of tree growth by existent visual observation by involution. This research presents general process that need in image processing of tree blazing fire, and that remove various noises that happen in above zero by measuring electrical tree dividing background and complete view in measured above zero taking advantage of specially proposed complete view object abstraction techniques effectively and quantification of tree becomes easy naturally, can apply to dielectric breakdown estimate because can chase growth process of tree.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.2
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• pp.87-93
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• 2022

The demand for metal-polymer joining technology have been increasing, especially in the industrial fields of automotive and aerospace, which require the manufacturing of various lightweight parts. Conventional joining processes have technical hurdles on aspects such as thermal degradation, need for chemical surface treatment, or complicated process settings. These issues can be alleviated by employing interlocking structures for the metal-polymer joined interface. In this study, we joined 3D-printed metal and polymer parts, which were featured with 3D-printed interlocking structures at their interface. By using high frequency induction heating, the joined region could be locally heated to reduce the thermal degradation and distortion of polymer parts. In addition, through the adjustment of interface morphologies and compression conditions, the polymer flow could be optimized to completely fill the interlocking grooves on metal parts, thereby achieving high joining strength. This suggests feasible guidelines for manufacturing metal-polymer joined structures involving 3D-printed architectures.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.1
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• pp.57-62
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• 2017

The purpose of this study is to develop a method for diagnosing the degree of gradual degradation of a reciprocating pump caused by continuous use as a water supply pump in a nuclear power plant. Normally, the progress of such degradation is too slow to be noticed. Hence, it is difficult to determine the degree of degradation using the existing diagnostic methods. In this paper, we propose a new method by which the normal state and the degraded state of the pump can be differentiated, so that the degree of degradation can be identified. First, an emulator was developed using FPGA by providing the parameters of the pump under normal state, so that the emulator generates the information of the pump in the healthy state. Then, by comparing this information with the parameters received from various output sensors of the emulator during the current state, it is possible to identify and measure the degree of gradual degradation. This paper presents some of the results obtained during the development process, and results that show how the emulator operates, by comparing the data collected from an actual pump.

• Journal of Environmental Science International
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• v.18 no.11
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• pp.1235-1245
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• 2009

The purpose of this study is to investigate electro-generation of free Cl, $ClO_2$, $H_2O_2$ and $O_3$ and degradation of Rhodamine B in solution using Ru-Sn-Sb electrode. Electrolysis was performed in one-compartment reactor using a dimensionally stable anode(DSA) of Ru-Sn-Sb/Ti as the working electrode. The effect of applied current (0.5-3 A), electrolyte type (NaCl, KCl, HCl, $Na_2SO_4$ and $H_2SO_4$) and concentration (0.5-2.5 g/L), air flow rate (0-3 L/min) and solution pH (3-11) was evaluated. Experimental results showed that concentration of 4 oxidants was increased with increase of applied current, however optimum current for RhB degradation was 2 A. The generated oxidant concentration and RhB degradation of the of Cl type-electrolyte was higher than that of the sulfate type. The oxidant concentration was increased with increase of NaCl concentration and optimum NaCl dosage for RhB degradation was 1.75 g/L. Optimum air flow rate for the oxidants generation and RhB degradation was 2 L/min. $ClO_2$ and $H_2O_2$ generation was decreased with the increase of pH, whereas free Cl and $O_3$ was not affected by pH. RhB degradation was increase with the pH decrease.

• Korean Journal of Environmental Agriculture
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• v.6 no.2
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• pp.73-76
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• 1987

The effects of light, active oxygen, inorganic $SO_3\;^{-2}\;ion$, $SO_2$ fumigation duration, $SO_2$ concentration on the degradation of photosynthetic pigments in Green perilla (Perilla frutescens Suwon No. 8) fumigated by $SO_2$ were investigated inside a phytotron. The results were as follows: 1. With the increase of the $SO_2$ dosage, visible injury and the degradation of chlorophyll increased. 2. The degradation of chlorophyll b was less than that of chlorophyll a and the carotinoid was more easily degratated than chlorophyll b. 3. The degradation of chlorophyll by $SO_2$ fumigation was induced directly by $SO_2$, itself. 4. Light is necessary to the degradation of chlorophyll. $SO_2$ and $O_2^-$ made in the photolysis process of the water molecule were the major components in the degradation of chlorophyll.