• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.2
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• pp.157-169
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• 2009

The aim of this study was to evaluate effect of implant abutment screw coating treatment on joint stability, investigating mechanical properties of these. For this study used $ExFeel^{(R)}$ external hexed implant system and $15mm{\times}1mm$ discs. Experimental group was $1{\mu}m$ TiN, TiCN, TiC coated abutment screws and discs. To know mechanical property, i evaluated adhesion strength, surface hardness, using disc, corrosion test using screw. The results were as follows : rotation angle of coated screws increased than that of non-coated screw because of lower friction coefficient, especially TiC coated screw group had the largest value, but removal torque decreased in all coated screws (p<0.05). Torque loss before and after fatigue test was the smallest in TiC-coated screws, and the largest in non-coated screws (p<0.05), and there was no statistically significant difference between dry condition and wet condition of screws because of higher surface hardness and lower friction coefficient. From the above results, TiN, TiCN, TiC coating group had high abrasion resistance, especially TiC coated group which had low torque-consuming, high rotation angle as low friction coefficient will be considered to influence on implant abutment screw joint stability positively.

• Geophysics and Geophysical Exploration
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• v.13 no.4
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• pp.323-329
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• 2010

Three deconvolution methods were applied to stacked seismic data obtained to investigate gas-hydrates in the Ulleung Basin, East Sea: (1) minimum-phase spiking deconvolution, (2) minimum-phase spiking deconvolution using an averaged wavelet from all traces, and (3) deterministic deconvolution using a wavelet with phases computed from well-logs. We analyzed the resolving property of these methods for lithological boundaries. The first deconvolution method increases temporal resolution but decreases lateral continuity. The second method shows, in an overall sense, similar results to the spiking deconvolution using a minimum phase wavelet for each trace; however, it results in a more consistent and continuous bottom-simulating reflector (BSR) and better resolved sub-BSR reflectors. The results from the third method reveal more detailed internal structures of debris-flow deposits and increased continuity of reflectors; in addition, the seafloor reflection and the BSR appear to have changed to a zero-phase waveform. These properties help more precisely estimate the distribution and reserves of gas hydrates in the exploration area by improving analysis of facies and amplitude of the BSR.

• Korean Journal of Environmental Biology
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• v.38 no.4
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• pp.554-562
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• 2020

Tremex fuscicornis (Siricidae), known as the xylophagous horntail, and Leucospis japonica (Leucospidae), known as the parasitoid wasp, are wood-boring wasps belonging to the order Hymenoptera. These insects are interesting sources of biological inspiration for the development of drilling mechanisms. To study the biomimicry aspects, the morphological characters of the ovipositor of T. fuscicornis and L. japonica were analyzed using a stereoscopic microscope, a field emission scanning electron microscope, and an optical microscope. There were many differences in the ovipositors between the two species, such as shape, length, surface structure, and arrangement of the teeth. Evenly arranged teeth were developed at the tip of both the dorsal valve and the ventral valve of the ovipositor of T. fuscicornis and looked like a rotating drill bit. In contrast, in L. japonica, the teeth, which looked like a saw, were found only on the ventral valve. Moreover, the tip of the ovipositor of T. fuscicornis was symmetrically divided into four parts, while that of L. japonica was divided into three parts having a 2:1:1 ratio. However, in the case of T. fuscicornis, after the 14th tooth, four parts melded into three parts maintaining a 2:1:1 ratio, and a dovetail joint was found on the horizontal cross-section of the ovipositor that allowed vertical movement for making a hole. These morphological differences of the ovipositor may be due to the insects' lifestyles and phylogenetic distance. Finally, zinc was commonly found at the tip of the ovipositors of both species, a probable result of ecological adaptation created by drilling wood.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.93-94
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• 2007

• Korean Architects
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• no.12 s.225
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• pp.64-69
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• 1987

우리는 석굴암에서 기능을 수용하는 건축물의 완전한 전형으로서 공간과 그 공간에 합치되는 내용물의 이상적인 결합을 보게되는 바, 그러한 이상적 공간이 인간들의 자파세계가 아닌 신들의 세계 즉 극락정토임은 합당한 일이다. 필자는 여기서 제작자가 단지 시공방법만을 고분에서 모방한 것이 아니라, 사후의 기대 공간인 극락정토의 이미지를 의도적으로 결합하고자 시도한 것이라 짐작한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1211-1212
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1209-1210
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• 2012

• ICROS
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• v.18 no.1
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• pp.36-41
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• 2012

박쥐는 초음파를 사용하여 획득한 정보를 바탕으로 집을 찾거나 먹이를 잡는 등의 복잡한 임무를 수행한다는 것을 보았을 때 박쥐의 초음파 시스템은 현재 우리가 사용하고 있는 기술보다 뛰어나다고 볼 수 있다. 따라서 박쥐의 초음파 시스템에 대한 연구를 바탕으로 공기 중에서의 초음파 기술에 적용하여 성능을 향상시킬 수 있을 것이다.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.152.1-152.1
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• 2005

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.59.1-59.1
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• 2005