• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.5
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• pp.88-93
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• 2012

This paper describes the machinability of the sintered carbide and tool-die steel(STD-11) by electric discharge drilling with various tubular electrodes which have multi-holes. Various types of electrode which have different diameters and materials are used with the application of continuous direct current and axial electrode feed. Inner part of electrodes are inserted with smaller tubes or Y-channel or bar. In ED-Drilling, the dielectric flushed down the interior of the rotating tube electrode, in order to remove machining debris from the hole. As result of experiments, the bigger the diameter of the electrode is, the lower the material removal rate is. Machinability of copper electrode is higher than that of brass. In machining of sintered carbide, to use oil is better than distilled water as dielectric.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.886-889
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• 2000

This paper describes the machining characteristics of the MoSi$_2$-based composites by electric discharge drilling with various tubular electrodes. MoSi$_2$-based composites has been developed in new materials for jet engine of supersonic-speed airplanes and gas turbine for high- temperature generator. By combining a nonconducting ceramics with more conducting ceramic it was possible to raise the electrical conductivity. In drilling by EDM, the dielectric flushed down the interior of the rotating tube electrode, in order to facilitate the removal of machining debris from the hole. Various metal-coated tubular electrodes of which core are copper and brass are used to know the effect of coating material on machinability of ED drilling.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.1001-1004
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• 2002

Accurate prediction of the transmission loss of dissipative silencers has been considered difficult due to the ambiguity and complexity in the physical properties of sound absorbing materials. Additional difficulty lies in the fact that the analytical calculation of the propagation constant is unknown yet. In this paper. as a first step toward obtaining the Propagation constant and thus predicting the transmission loss, an approximation equation stemming from the wave analysis in the lined interior has been derived. Such an analytical solution and numerical solution using the boundary element method are compared for a two-dimensional simple dissipative silencer under the assumption of the locally reacting sound absorbent.

• Advances in concrete construction
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• v.4 no.4
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• pp.305-317
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• 2016

Porous materials such as concrete could be subjected to aggressive ions transport. Durability of cement paste is extremely depended on water and ions penetration into its interior sections. These ions transport could lead different damages depending on reactivity of ions, their concentrations and diffusion coefficients. In this paper, chloride diffusion process in cement hydrates is simulated at atomistic scale using molecular dynamics. Most important phase of cement hydrates is calcium silicate hydrate (C-S-H). Tobermorite, one of the most famous crystal analogues of C-S-H, is used as substrate in the simulation model. To conduct simulation, a nanopore is considered in the middle of simulation cell to place water molecules and aggressive ions. Different chloride salts are considered in models to find out which one is better for calculation of the transport properties. Diffusion coefficients of water molecules and chloride ions are calculated and validated with existing analytical and experimental works. There are relatively good agreements among simulation outputs and experimental results.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.5
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• pp.43-51
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• 2015

This research was performed to investigate the quality of leaflets provided with newspapers. The leaflets were classified according to business types and regions. The physical and strength properties were analyzed. The sizes of leaflets were 2, 4, 8 jeoljis of crown octavo, A3, A4, A5, and B3, B4, B5. Most of them were color printed and both-sides printing was much more popular than one-side printing. The leaflets about electronics, educations, and clothing showed lower density than restaurant business and other areas. The leaflets of electronics, educations, and clothing, and large stores showed lower tensile strength, and those of restaurant businesses and building trades showed relatively high tensile strengths. No differences on the quality of leaflets except for large stores were found according to business areas. Large markets made the leaflets with various types of papers, and low quality papers were also included.

• Journal of the Korean Graphic Arts Communication Society
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• v.24 no.2
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• pp.49-59
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• 2006

In this paper, a transparent film exposed the effect of heat cut-off, reveal as means of the prevention to wrong operation of parts of display and forgery of the credit card, also it will intercept rising of the temperature in interior of a room and car by diminish the influx of near-infrared ray wavelength of solar energy come from the window. As in the past a film which absorb a wavelength of $800{\sim}2500nm$ in near-infrared ray, manufactured in physical vapor deposition(PVD), chemical vapor deposition(CVD) to using ATO, ITO of inorganic materials or sputtering method. but it has lots of problem in manufacture. On the other hand, recently a paper said it easily form a transparent film to using organic dye. This paper show synthesis of many derivatives used in Ni-complex and then it investigate to optical property and durability of flim by make the transparent film.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.6
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• pp.55-63
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• 2013

To offer a basic information for the fibers of commercial leaflets, authors examined and analyzed the distribution, size, and printing types of leaflets sandwiched in the newspaper. The number of different leaflet size were almost 30 in two years including B5 ($182{\times}257mm$), A4 ($210{\times}297mm$), B4, ($257{\times}364mm$), A3 ($297{\times}420mm$), and large flyers such as $545{\times}395mm$, and $790{\times}550mm$. The number of different leaflets size were 25 in 2011, which was reduced to 15 in 2012. Both the number and amount of the leaflets were reduced. The high quality leaflets were issued and distributed in the corporate sector and the leaflets issued in other sectors such as shopkeeping, restaurant business, educational institutions were one-sided leaflets printed on single side of the paper. Compared to the previous year, large stores showed the increased number of leaflets but the number of leaflets from restaurant business and educational institutions and building trade were decreased.

• Structural Engineering and Mechanics
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• v.53 no.4
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• pp.703-723
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• 2015

In this paper optimization of volume fraction distribution in a thick hollow cylinder with finite length made of two-dimensional functionally graded material (2D-FGM) and subjected to steady state thermal and mechanical loadings is considered. The finite element method with graded material properties within each element (graded finite elements) is used to model the structure. Volume fractions of constituent materials on a finite number of design points are taken as design variables and the volume fractions at any arbitrary point in the cylinder are obtained via cubic spline interpolation functions. The objective function selected as having the normalized effective stress equal to one at all points that leads to a uniform stress distribution in the structure. Genetic Algorithm jointed with interior penalty-function method for implementing constraints is effectively employed to find the global solution of the optimization problem. Obtained results indicates that by using the uniform distribution of normalized effective stress as objective function, considerably more efficient usage of materials can be achieved compared with the power law volume fraction distribution. Also considering uniform distribution of safety factor as design criteria instead of minimizing peak effective stress affects remarkably the optimum volume fractions.

• Fashion & Textile Research Journal
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• v.14 no.3
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• pp.363-370
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• 2012

This study is for the development of fashion cultural products that simultaneously evolved with the contemporary use of traditional temple culture in addition, it analyzed the cultural products available in the Korean market. Methodology, this study conducted a literature review and empirical research. We targeted the cultural products carried at twelve web-based shopping malls for Buddhist cultural products and six souvenir shops in Korean Buddhist temples to collect data on those products in order to analyze the items, design motives, materials, and price ranges. The study results showed that interior items represented the largest portion of the targeted goods, followed by accessories/sundries, clothing/fashion items, stationery, and tableware. The most commonly used design motive was lotuses, followed by the images of Buddha or Buddhist Goddesses and Dharma. The most common materials include fibers, jewelry (such as gold and silver), wood, metals, ceramics, paper, and plastic. The most active price range was between KRW10,000 and KRW50,000, followed by less than KRW10,000 and KRW100,000 to less than KRW500,000. This study discovered the potential for traditional temple culture to advance it further in a contemporary manner and indicated the need to develop a wide variety of cultural products and emphasize its global acceptance.

• Journal of the Korea Furniture Society
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• v.28 no.3
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• pp.233-247
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• 2017

Woodcraft activities have an inseparable relationship with our daily life, and it is a field that needs to be continued because of the value of education for the growing students. The interest in woodworking from childhood to old age is rapidly expanding nowadays, therefore this study has been done to provide images to those who are engaged in woodcraft business and also those who are interested in this field. If we look at the use of wood in our daily life, We can classify it into Architecture, Civil engineering, Furniture, Musical Instrument, Packaging, Recreational instrument, Exercise instrument, Stationery, Daily commodity, and Industrial use. Among them, We examined kinds of stationery and which type of woods were used. As a result of classifying 101 stationery products in 22 countries, stationery materials using wood can be used for Business cards, Envelope houses, Box houses, Pen holders, Locker plates, Stationery baskets, Book holders, Stamps, Paper knives, Bookmarks, and Photo frames. It was found various wooden stationery are made in USA, Japan, UK, Canada etc. And the most frequently used species are hardwoods such as Walnut (Juglans regia), Maple (Acer spp.), Cherry (Prunus serotina), Birch (Betula spp.), Mahogany (Swietenia macrophylla), Tulip (Liriodendron tulipifera Linnaeus), Bubinga (Guibourtia tessmannii J. Leonard), Wenge (Milletia laurentii De. wild), Cocobolo (Dallbergia cultrata Grah), Zebrawood (Microberlinia brazzavillensis A. Chev.) and Ebony (Diospyros spp.).