• Journal of the Semiconductor & Display Technology
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• v.12 no.2
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• pp.45-50
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• 2013

This paper focuses on the fundamental issues for improving the efficiency and throughput of the AC PDP (Plasma Display Panel) manufacturing. The properties of the MgO protective layer affect the PDP efficiency. Especially, the secondary electron emission efficiency was affected on the deposition rate of MgO during the evaporation. In this study, the deposition rate of 5 $\AA$/s has given the maximum efficiency value of 0.05 It is demonstrated that the impurity gases such as $H_2O$, $CO_2$, CO or $N_2$, and $O_2$ can be remained inside the PDP panel before sealing and the amount of the impurity gases decreased rapidly as the base vacuum level increased, especially near $10^{-5}$ torr. The fundamental solution in order to overcome these problems is the vacuum in-line sealing process from the MgO evaporation to the final sealing of the panel without breaking the vacuum. We have demonstrated this fundamental process technology and shown the feasibility. The firing voltage was reduced down to 285 V at the base vacuum value of $10^{-6}$ torr, whreras it was about 328 V at the base vacuum value of $10^{-3}$ torr.

• Resources Recycling
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• v.9 no.6
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• pp.53-57
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• 2000

In the present paper, a current technical progress for recycling of used steel can is described. The developed technology was a kind of pre-treatment through an automatic equipment system to increase recycling and melting efficiency of used steel co. The process consisted of several unit processes such as breaking of steel can bale, removing dust, separation of aluminum can, delacquering, and compressing to bale. Also, aluminum powders were recovered as a by-product at the delacquering step. The process was carried out automatically through by use of the developed equipment system. The automatic system could be very available in mass treatment of used steel can.

• Journal of Conservation Science
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• v.35 no.1
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• pp.33-40
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• 2019

During the conservation and maintenance of the birthplace center yard of President Asan Yoon Bosun, four porcelain enamel dishware were excavated from the central yard well. The glaze layer of excavated enamel was severely damaged; hence, the conservation process was done rapidly. In addition, scientific investigation and analysis were conducted to confirm the material properties of the glaze layer. It was confirmed that the outer surface was inverted and dried, while the inner surface was upright and fired during the glazing and drying process by measuring the film thickness. By examining the breakup phenomenon, the breaking up of the white enamel on the colored enamel was confirmed. This indicates that the colored glaze rose to the surface depending on the density of the colored glaze and white glaze. The investigation of the cross-section of the film confirmed that the lower layer formed according to the bonding properties with metal during the glazing process. Analysis of the constituents of the identified lower layer confirmed that there are differences between the specific components of the metal oxide of the lower layer and the surface color development of the upper layer.

• Korean Journal of Materials Research
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• v.30 no.12
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• pp.672-677
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• 2020

Expensive PCBN or ceramic cutting tools are used for the processing of difficult-to-cut materials such as Ti and Ni alloy materials. These tools have a problem of breaking easily due to their high hardness but low fracture toughness. To solve this problem, cutting tools that form various coating layers are used in low-cost WC-Co hard material tools, and researches on various tool materials are being conducted. In this study, WC-5, 10, and 15 wt%Ni hard materials for difficult-to-cut cutting materials are densified using horizontal ball milled WC-Ni powders and pulsed current activated sintering method (PCAS method). Each PCASed WC-Ni hard materials are almost completely dense, with a relative density of up to 99.7 ~ 99.9 %, after the simultaneous application of pressure of 60 MPa and electric current for 2 min; process involves almost no change in the grain size. The average grain sizes of WC and Ni for WC-5, 10, and 15 wt%Ni hard materials are about 1.09 ~ 1.29 and 0.31 ~ 0.51 µm, respectively. Vickers hardness and fracture toughness of WC-5, 10, and 15 wt%Ni hard materials are about 1,923 ~ 1,788 kg/mm2 and 13.2 ~ 14.3 MPa.m1/2, respectively. Microstructure and phase analyses of PCASed WC-Ni hard materials are performed.

• Journal of Engineering Education Research
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• v.25 no.6
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• pp.58-68
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• 2022

This paper aims to prepare basic design education materials explaining the design process of egg drop device by incorporating critico(-creative) thinking. To this end, in this paper, by utilizing the creative problem solving process and the elements and standards of critical thinking, 'the five-step creative engineering design education guidelines' have been prepared so that engineering freshmen can effectively participate in engineering design projects without major knowledge. We would like to apply them to the egg drop device design. The egg drop device design, which is experiment to make and drop a drop device that can protect an egg from breaking when it is dropped freely from high places, is an engineering design project that is widely used not only in elementary, middle and high school science events but also in engineering education courses under the name of 'stunt egg'. Perhaps the basic design education material on the egg drop device design incorporating critico(-creative) thinking in this paper will contribute to incorporating critico(-creative) thinking into engineering education, as well as to achieving the educational goals of the basic design subject.

• Transactions on Electrical and Electronic Materials
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• v.13 no.6
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• pp.273-277
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• 2012

The vacuum drying process for drying of paper in current transformers was modeled with an aim to develop an understanding of the drying mechanism involved and also to predict the water collection rates. A molecular as well as macroscopic approach was adopted for the prediction of drying rate. Ficks law of diffusion was adopted for the prediction of drying rates at macroscopic levels. A steady state and dynamic mass transfer simulation was performed. The bulk diffusion coefficient was calculated using weight loss experiments. The accuracy of the solution was a strong function of the relation developed to determine the equilibrium moisture content. The actually observed diffusion constant was also important to predict the plant water removal rate. Thermo gravimetric studies helped in calculating the diffusion constant. In addition, simulation studies revealed the formation of perpetual moisture traps (loops) inside the CT. These loops can only be broken by changing the temperature or pressure of the system. The change in temperature or pressure changes the kinetic or potential energy of the effusing vapor resulting in breaking of the loop. The cycle was developed based on this mechanism. Additionally, simulation studies also revealed that the actual mechanism of moisture diffusion in CT's is by surface jumps initiated by surface diffusion balanced against the surrounding pressure. Every subsequent step in the cycle was to break such loops. The effect of change in drying time on the electrical properties of the insulation was also assessed. The measurement of capacitance at the rated voltage and one third of the rated voltage demonstrated that the capacitance change is within the acceptance limit. Hence, the new cycle does not affect the electrical performance of the CT.

• Science of Emotion and Sensibility
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• v.13 no.4
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• pp.687-692
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• 2010

This paper surveys emission characteristics of Far-infrared of the fabrics fabricated with germanium imbedded sheath-core conjugate composite filaments. For this purpose, master batch chip was prepared with PET semi-dull chip and nano sized germanium particles and sheath-core type conjugate composite filament was spun using this master batch chip and polyester semi dull. The emission power and emissivity of the germanium imbedded fabrics were measured and investigated using FT-IR spectrophotometer by KICM- FIR 1005 measurement method. In addition, the fabric mechanical properties were measured and discussed with the effects of the optimum texturing process conditions and fabric structural design conditions. The sheath/core type PET composite germanium imbedded filaments were manufactured by the optimum spinning condition, its tenacity and breaking strain showed the same level as the regular PET filament. The tenacity and breaking strain of the DTY showed good physical properties and no problem in the weaving process. Then, wet and dry shrinkages showed higher values than those of regular PET filament. The emission power of the germanium imbedded fabric was $3.53{\times}10^2W/m^2$ at the $5-20{\mu}m$ wave length range, and emissivity was 0.874. The fabric hand of germanium imbedded fabrics was inhanced by the optimum texturing process and fabric structural design with improved mechanical properties such as fabric bending and compressional properties.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.5
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• pp.488-497
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• 2009

The freak wave, also known as New-Year-Wave in the north Atlantic, is relatively large and spontaneous ocean surface wave that can sink even large ships and destroy maritime structures. To understand oceanic conditions that develop freak waves, we simulated and generated two versions of scale-downed waves (1:64 and 1:42) in a numerical wave tank and compared the results with the experiment in wave flume. Both of the breaking and non-breaking waves were generated in the simulation. The numerical simulation was implemented based on the finite volume method and a genetic optimization algorithm. Random values were assigned as the initial values for the parameter in the control function, which produced signals representing the motion of wave-maker. The same signal obtained from the optimization process was used for both of the simulation and the experiment. By varying the object function and restrictions of the simulation, a best profile of design wave was selected based on the characteristics, height and period of simulated waves. Results showed that the simulation and experiment with the scale of 1:42 agreed better with freak waves in the natural condition. The presented simulation method will contribute to saving the time and cost for conducting subsequent response analyses of motion under freak waves in the course of the model test for ship and maritime structure.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.4
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• pp.166-171
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• 2008

We studied the variety and affinity between the successive words in the text document A number of groups were defined by the frequency of a following word in the whole text (corpus). In the previous studies, the Zipf's power law was explained by Chinese restaurant process and hub node was searched after by examining the edge number profile in scale free network. We have observed both a power law and a hub profile at the same time by studying the conditional frequency and degeneracy of a group. A symmetry between the affinity and the variety between words were found during the data analysis. And this phenomenon can be explained within a viewpoint of "exploitation and exploration." We also remark on a small symmetry breaking phenomenon in TIPSTER data.

• Journal of the Korean Society of Clothing and Textiles
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• v.13 no.4
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• pp.357-369
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• 1989

The purpose of this study was to investigate the effects of treatment temperature and time on the, of easy-care and strength properties of the wet fixation processed rayon fabrics. Viscose rayon fabrics were treated with mixed resins of melamine formaldehyde (MF) and DMDHEU by one bath and two bath wet fixation processes. The MF/DMDHEU mixed resin concentrations were 50/100, 50/150, 100/100 and 100/150(g/1). Magnasium chloride was used as a catalyst. The wet fixation conditions were 24hrs at room temperature,20 mins at $75^{\circ}C$ and 5 mins at $105^{\circ}C$ Wet fixation processed fabrics did not show the difference in the resin add-one, DP ratings and wrinkle recovery angles by the different treatment temperatures and times. DP ratings were in the order of $105^{\circ}C>75^{\circ}C>room$ temp, in one bath and two bath wet fixation. Breaking and tearing strength of one bath processed fabrics showed in the order of $75^{\circ}C>room\;temp>105^{\circ}C$ The breaking strength of two bath processed fabrics showed in the order of $105^{\circ}C>75^{\circ}C>room$ temp. Tearing strength showed in the order of $75^{\circ}c>105^{\circ}C>room$ temp. Abrasion resistances were in the order of $75^{\circ}C>105^{\circ}C>room$ temp. in one bath and two bath processes.