• Proceedings of the Zoological Society Korea Conference
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• 2003.08a
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• pp.211.1-211
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• 2003

No Abstract, See Full Text

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.93.4-93
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• 1998

• Journal of The Korean Association of Information Education
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• v.24 no.6
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• pp.539-550
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• 2020

This study establishes the scientific basis for the use of digital learning materials through the education-neurological research method and derives implications for education based on education-neurological understandings. The main findings of the education-neurological analysis of digital learning materials are as follows: First, various sensory stimuli go through multiple sensory neurons and deep sections of the upper sphere and make possible the cooperative processing of information. Second, indirect experience from digital learning materials helps students understand the learning contents vividly through the mirror neuron system. Third, positive emotions originating from digital learning materials promote functions of dopamine, the reticular activating system, frontal-striatal circuit, cerebrum cortex. Based on the findings, the study suggests the following educational implications. First of all, when selecting digital learning materials, teachers should consider expression forms, learning contents, the flow of classes, and the adverse effects of digital learning materials. Next, it is effective to utilize digital learning materials in the lecture for provoking curiosity and enjoyment, maintaining interest and effort, and reviewing what students learned.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.11a
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• pp.10-10
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• 2007

• Korean Journal of Materials Research
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• v.16 no.7
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• pp.439-444
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• 2006

An apparatus capable of melting and solidifying various materials containerlessly in high vacuum via electrostatic levitation (ESL) has been developed for finding materials with new or improved properties and further building a database for processing materials in microgravity. Containerless solidification of semiconductors, metals, and alloys such as Si, Zr, Nb, Mo, $V_3Si$, and boron carbides has been carried out to test how various materials at how high temperatures can be processed by ESL. The materials in levitation became spherical at melting by their own surface tensions which were ideal for measuring intrinsic thermophysical properties of materials in the liquid state. Multiple cycles of melting and cooling were reproducibly repeated and radiative cooling curves were recorded.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.54-54
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• 2003

We have developed a Cu-based bulk amorphous composite reinforced with a micron-sized crystalline phase, the (Cu60Zr30Ti10)95Ta5 amorphous matrix composite. The composite demonstrates the ultimate strength of 2332 MPa with a dramatically enhanced fracture strain of 15.3 %. Macroscopic observation of the fractured (Cu60Zr30Ti10)95Ta5 amorphous matrix composite showed the development of multiple shear bands along with numerous branching and deflection of shear bands. Microscopic observation on the amorphous matrix of the composite showed that cracks propagate through the residual amorphous matrix located between nanocrystallites, which had formed during deformation. Simulations based on finite element method were conducted to understand the formation mechanisms of multiple shear bands, the initiation site of shear bands, and interaction of shear bands with crystalline particles. Other microscopic fracture mechanism responsible for the enhanced plasticity was discussed.

• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.2
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• pp.73-82
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• 2003

For measurements and analysis of dielectric characteristics of planar slabs of microwave absorbing materials, I have applied a free-space method in the frequency range of 8~14 GHz. The measurement system for free-space method consists of transmit and receive antennas, mode transitions, precision coaxal cables, the network analyzer, and a computer Special Spot-focused horn lens antenna was used to eliminate diffraction effects. Diffraction effects at the edges of the sample are minimized by satisfying the condition for minimum transverse dimension of the plate and the beamwidth of the antennas at the focus. The time-domain gating feature of the network analyzer and the thru, reflect, and line(TRL) calibration technique were used to eliminate the effects of undesirable multiple reflections. The complex coefficients of reflection and transmission, $S_{11}$ and $S_{21}$, of planar samples were measured for standard materials such as Teflon, Rexolite$\textregistered$ 2200. The results were compared with existing measurement method. And I applied a free-space method for measurement to measure dielectric constants of some electromagnetic absorbing materials. Dielectric properties for the same samples were also measured with a 7mm coxial transmission line method for purposes of comparison with the free-space method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.2
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• pp.137-143
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• 2012

Currently, in order to meet the reinforced emissions regulations for harmful exhaust gas including carbon dioxide ($CO_2$) as a greenhouse gas, technologies for reducing $CO_2$ emission and fuel consumption are being developed. Gasoline direct injection (GDI) systems have the advantage of improved fuel economy and higher power output than port fuel injection gasoline engine systems. The aim of this study is to examine the performance and emission characteristics of a lean burn GDI engine equipped with spray-guided-type combustion system. Stable lean combustion was achieved with a late fuel injection strategy under a constant operating condition. Further improvement in specific fuel consumption is possible with the introduction of multiple fuel injection strategies, which also increases hydrocarbon (HC) and nitrogen oxide ($NO_x$) emissions and decreases carbon monoxide (CO) emission.

• Korean Institute of Interior Design Journal
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• v.26 no.2
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• pp.83-91
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• 2017

This study was conducted by the awareness that although interior spaces using the techniques and characteristics of assemblage are excellent means to reveal distinctiveness and identity with preeminent originality which are different from other spaces, there are few domestic studies and literatures on them. The results analyzed by preceding studies and cases on the characteristics of expression of assemblage which appear in the interior spaces of commercial areas can be summarized as follows; First, assemblage expresses identity of spaces with symbols capable of multiple interpretations through the method of integration and repetition of the materials used. Second, it strongly reminds visitors of memories on spaces by producing odd and unfamiliar scenes with such designs as installation art. Third, when it uses ordinary materials, it adds combination, integration, transformation or colors to the materials for extraordinary traits. Fourth, it pursues sustainability through recycling or upcycling by using wastes or natural materials. Fifth, in order to express materials to fit the purposes of spaces, it formulates outcomes with intentional plans. To sum up above analysis results, expressions of assemblage which appear in modern commercial spaces are characterized by expression of symbols with multiple meanings, purse formativeness which fit the purposes and meanings of spaces, play the role of reminding memories on places by producing extraordinary spaces with strangeness and unfamiliarity such as installation art and sometimes show sustainability by using recyclable materials. The results of this study are expected to be utilized as reference materials which suggest directions of approach to interior spaces through assemblage techniques and materials which can be used in various design terms by domestic designers.

• ETRI Journal
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• v.34 no.6
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• pp.954-957
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• 2012

Titanium foils for use in photoelectrochemical devices are treated with a $HNO_3$-HF solution. After this treatment, the optical reflection characteristics of the Ti substrates are markedly increased in terms of not only reflectivity but also optimized wavelength. Furthermore, the "multiple beam interference" theory and optical analysis of surface morphologies clearly verify the origin of the optimized optical reflection properties.