• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1047-1055
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• 2006

We patterned nano-width lines on a super hard bulk diamond substrate by varying the ion beam current and ion beam sources with a dual beam field ion beam (FIB). In addition, we successfully fabricated two-dimensional nano patterns and three-dimensional nano plate modules. We prepared nano lines on a diamond and a silicon substrate at the beam condition of 30 kV, 10 pA $\sim$ 5 nA with $Ga^+$ ion and $H_2O$ assisted ion sources. We measured each of the line-width, line-depth, etched line profiles, etch rate, and aspect ratio, and then compared them. We confirmed that nano patterning was possible on both a bulk diamond and a silicon substrate. The etch rate of $H_2O$ source can be enhanced about two times than that of Ga source. The width of patterns on a diamond was smaller than that on a silicon substrate at the same ion beam power The sub-100 nm patterns on a diamond were made under the charge neutralization mode to prevent charge accumulation. We successfully made a two-dimensional, 240 nm-width text of the 300-lettered Lord's Prayer on a gem diamond with 30 kV-30 pA FIB. The patterned text image was readable with a scanning electron microscope. Moreover, three dimensional nano-thick plate module fabrication was made successfully with an FIB and a platinum deposition, and electron energy loss spectrum (EELS) analysis was easily performed with the prepared nano plate module.

• Journal of the Korean Geosynthetics Society
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• v.18 no.3
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• pp.45-53
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• 2019

In this study, it was analyzed the cases of bored PHC piles designed for the building foundations. The overall length of the piles varies within a maximum of 35 m. However, the average length was 17.0 to 18.9 m depending on the kind of the bedrock, with no significant difference. The socket length entered into the bedrock was designed with approximately 58% of the whole piles being 1m, the minimum length of the specification, and up to 5m. Although the range in design efficiency was very large, on average it was about 70%, consistent with the usual known extent. Applications with low design efficiency were mainly shown on the foundation of low-rise buildings or rides with low design load. On the weathered rock, the design load, which governs the design result was widely distributed at 65 to 97% of allowable bearing capacity of ground. The ratio of allowable axial load of piles to allowable bearing capacity of ground is also widely distributed between 36 and 115%, so optimization efforts are required along with design efficiency. On the other hand, the allowable bearing capacity on the soft or hard rock was highly equal, mostly within 90% of the allowable axial load of piles. In the design, the end bearing resistance averaged over 75% of the allowable bearing capacity. However, the results of the dynamic pile load test show that the end bearing resistance was predominant under the E.O.I.D conditions, and in some cases, the end bearing resistance was at least 25% under the restrike conditions.

• Fire Science and Engineering
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• v.27 no.6
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• pp.21-25
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• 2013

Fire resistance steel, grading 490 MPa, had developed by using Thermo-mechanical control process (TMCP) and it has better performance at welding, seismic resistance than those of the ordinary structural steel, But the fire resistance performance is required to verify against the ordinary fire resistance, FR 490. Therefore this study was done to make database of mechanical properties at high temperature and to evaluate the structural stability at high temperature in terms of materials and structural member such as H-section from that of FR 490. The result of this study was that the structural stability of TMCP was lower than that of ordinary FR 490 at the range up about $700^{\circ}C$.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.47-47
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• 2011

최근 m-Aramid 섬유의 염색에 대한 연구가 진행되면서 기존의 원착법 및 초고온고압법 등 상업성이 낮거나 제약이 많았던 염색법에서 차츰 cationic dye를 이용한 염색법이 상용화되고 있다. m-Aramid 섬유는 amide기의 분자 간 수소결합으로 인하여 결정화도를 증가시킴으로서 고강도, 고탄성의 특성을 가질 수 있지만, 강력한 분자구조와 고결정성의 치밀구조로 인하여 염료가 섬유의 분자구조 내부로 확산, 염착되기 어려운 단점을 가지기도 한다. 따라서 m-Aramid 섬유를 침염법으로 염색 시, 섬유의 치밀구조를 이완시켜줄 수 있는 swelling agent가 중요하게 작용한다. 본 연구에서는 cationic dye를 이용하여 swelling agent의 영향성을 살펴보았다. 사용된 시료는 100% m-Aramid 섬유이며, C.I. Basic Yellow 28, Red 46, Blue 54를 사용하여, 욕비 1:10, $NaNO_3$ 7g/l의 조건으로 $130^{\circ}C{\times}60$분간 염색하였다. 이때 사용된 Swelling agent는 두 가지로 각각 1-phenoxypropan-2-ol(S1)과 N-methyl formanilide(S2)를 주성분으로 한다. 염색 시 염료의 농도는 0.5~7% o.w.f.이며, 염색 전 후 염욕을 UV-VIS을 통해 absorbance값을 측정하여 산출한 염착율과, CCM을 사용하여 최대흡수 파장에서 산출 된 K/S값을 비교 고찰 하였다. 각각의 염색물을 비교한 결과 Red 염료를 제외한 yellow 및 blue 모두 3% o.w.f. 염료농도까지 90% 이상의 흡착율을 보였으며, S1에 비해 S2의 경우 염착율이 근소하게 높은 결과를 보였다. 반면 K/S 값을 비교해보면, S2를 사용하였을 때 10%~60% 높은 K/S값을 보였다. 염착율은 비슷하지만 K/S값의 차이를 보이는 이유는 염색이 끝난 후 수세과정에서 섬유표면에 미고착된 염료들이 빠져나가는 것으로, 이를 통해 S2의 경우 섬유의 내부로 염료를 잘 고착시켜 줌으로서 수세안정성이 S1에 비에 우수한 결과를 보인 것으로 고찰된다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.135-136
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• 2016

SUPER concrete poontoon is developed to overcome shortcomings about corrosion problem of steel pontoon and the insufficient freeboard line of concrete pontoon. Top slab of Pontoon resists truck load or sidewalk live load. The soffit slab and outer wall of Pontoon resist the horizontal and vertical components of wave pressure, and those were loaded along X and Y-axis of Pontoon. Global analysis for the Pontoon is carried out to design its cross-sections economically using a geometric non-linear time history analysis method by Strand7 and buoyance-stability calculated automatically on non-vertical boundary conditions. And the load-capacity of Pontoon is confirmed through mock-up tests.

• Ocean and Polar Research
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• v.32 no.2
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• pp.157-164
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• 2010

A marine alga, Spirulina maxima, was extracted under high pressure and low temperature conditions at 500 MPa and $60^{\circ}C$ for 5 and 10 min. A high pressure of 500 MPa was applied to improve process yields because of low temperature extraction. This method resulted in highest higher extraction yield of 26.1% (w/w) in comparison to those results obtained from conventional extraction methods which produced a yield of 17.6% (w/w) from water. The extracts from this process also showed 19% of low cytotoxicity against human normal fibroblast cells in adding 1.0 mg/ml of the highest concentration. The crude extract significantly reduced the production of Prostaglandin $E_2$ ($PGE_2$) from CCD-986sk cells and increased nitric oxide production by macrophages. These higher activities of enhancing skin immune functions were found to have high antioxidant extract properties, like a 98% increase in DPPH radical scavenging activity. The extracts from the high pressure process showed a higher elution of active components than other processes and generated new compounds based on HPLC analysis. This clearly indicates that the extracts from high pressure and low temperature conditions have higher skin immune activation properties that have not been previously reported.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.5
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• pp.533-551
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• 2015

The rock fracturing during waterjet cutting is very complicated because rock is inhomogeneous and anisotropic, compared with artificial materials (e.g., metal or glass). Thus, it is very important to verify the effects of rock properties on waterjet rock cutting performance. Properties affecting the rock cutting efficiency have been variously described in the literature, depending on the experimental conditions (e.g., water pressure, abrasive feed rate, or standoff distance) and rock-types studied. In this study, a rock-property-related literature review was performed to determine the key properties important for waterjet rock cutting. Porosity, uniaxial compressive strength, and hardness of the rock were determined to be the key properties affecting waterjet rock cutting. The results of this analysis can provide the basic knowledge to determine the cutting efficiency of waterjet rock cutting technology for rock excavation-related construction.

• Journal of Korean Society of Steel Construction
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• v.27 no.1
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• pp.43-52
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• 2015

Constructions of buildings downtown are increasing as much as ever with a strong demand. Top-Down Method is suitable for its advantage in minimizing its disturbance to the neighborhood. Pre-founded when applied to CFT Column on-site welded is required for splicing. To complement the welded built-up square composite Column was developed. Top-down process will be pouring concrete in accordance with a step-by-step process. Thus, Pre-founded Column and cover concrete to determine the stress condition. Therefore, Concrete filled steel square tubular columns encased with precast concrete were studied. Five Centrally loaded Columns were tested to investigate the axial load carrying capacity. we analyzed the strength and behavior of CET Column by Loading conditions and concrete strength, thickness of cover concrete through structure experiments.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.61-64
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• 2008

A combination of CFT column and RC flat plate without formworks is very effectively rapid constructions. This paper verified the lateral resisting capacity of CFT column-RC flat plate exterior connection in comparison with general RC column-flat plate connection and detected moment capacity and ductility capacity of connection according to moment-displacement ratio. We made and tested specimens which have different variables respectively and as a result derive a following conclusion. In CFT-E2 specimen a critical section was extended and maximum moment increased 20% respectively in comparison to general RC column specimen. In BME and CFT-E1 specimens generally shear governed behaviors and CFT-E2 specimen complemented with seismic band, flexure behavior region of slab was extended and also ductility ratio and energy absorptance increased.

• Korean Journal of Construction Engineering and Management
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• v.13 no.2
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• pp.25-36
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• 2012

As the international construction market is rapidly expanding, Korean contractors have the need for having new leading businesses for their sustainable growth and high performance. Thus, this research tried to explore new leading businesses with two questions: 'What can be the new leading businesses?' and 'How can Korean contractors implement new leading businesses?' To this end, based on Porter's five forces framework and the resource-based view (RBV), we first derive three evaluation criteria (possibility of market entry, possibility of profit earning, and possibility of value-added earning). Next, we developed a framework for business evaluation which considers external market condition, internal competitiveness, and spin-off effects toward domestic market. Based on the framework, we defined green-energy plant, environmental plant, desalination plant, nuclear power plant, new urban development, and high-rise building as new leading business. Then, we selected green energy plant, environmental plant, and new urban development for the purpose of prior occupation of the market, consolidation of the competitiveness, and expansion of the ripple effect, respectively. Finally, we deduced market entry strategies for each business by investigating experts' opinions.