• Proceedings of the Korean Nuclear Society Conference
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• 1995.05b
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• pp.781-786
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• 1995

석탄화력발전소 산업부산물인 Fly ash를 이용한 고준위방사성폐기물의 붕규산 유리고화 가능성을 분석하였다. Fly ash SiO$_2$, NaNO$_3$, B$_2$O$_3$에 DUPIC 핵연료 제조공정으로부터 발생되는 모의 scrap waste를 20 wt% 혼합하여, l15$0^{\circ}C$ 에서 3시간 용융시켜 붕규산유리화시켰다. 또한 붕규산유리고화체의 침출성을 평가하기 위하여 2일동안의 soxhlet 침출실험결과 양호한 내침출성을 보였다. 또한 고체폐기물의 안정화물질로 fly ash를 사용할 경우 fly ash 함량을 57%까지 첨가하여도 붕규산유리고화체의 제조가 가능함을 확인하였으며, fly ash의 첨가로 인한 유리화원료 재료비를 30% 까지는 절감시킬 수 있을 것으로 예상된다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.07a
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• pp.218-219
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• 2015

본 논문에서는 스마트폰으로 촬영한 비디오 영상이나 일반 캠코더로 촬영한 비디오 영상을 4K 고화질 콘텐츠로 제작하는 것을 제안한다. 대화면 디스플레이와 고해상도 디스플레이가 점차 확대되면서 고화질 콘텐츠의 필요가 증대됨으로 이에 일반적으로 촬영된 영상을 비디오 편집기법을 이용하여 4K 고화질 해상도의 영상 제작을 제안하다. 하지만 일반 비디오카메라로 촬영한 영상을 4K 콘텐츠로 완전히 적용하기 위해서는 촬영에서 4K 카메라로 촬영하고 편집하면 4K 콘텐츠로 보다 해상도가 높은 콘텐츠를 제작할 수 있다고 사료한다.

• 발명특허
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• v.26 no.10 s.306
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• pp.76-83
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• 2001

본 발명은 승화성 고체 미립자 제트를 이용한 분사로 표면의 오염물을 제거하는 공정이다. 이는 극저온에서 고화된 입자가 표면에 고속 충돌 후 오염물을 제거하고 자신은 승화되어 잔사를 남기지 않는 청정 세척 공정을 말하는데 반도체 장비, 정밀 제품, 인쇄회로 기판 등의 다양한 표면의 각종 오염막 제거에 널리 사용될 수 있다. 본 장치의 특징은 세정 매체인 $CO_2$와 Carrier gas인 $N_2$를 사용하였고 현재 특허에 출원되어 있는 단순한 액체$CO_2$를 이용한 세정범위를 넘어 다양한 세정매체 즉, 복합인자($CO_2$ + ice, Ar + ice)를 이용하여 세정효율의 다변화를 이루었고 자체 개발한 냉동기를 이용하여 고화율이 액체 $CO_2$보다 상대적으로 낮은 기체 $CO_2$의 고화율을 증대 시킴으로써, 세정매체의 소모시간이 현격히 감소되어 원가절감 효과를 증대 시켰다. 세정대상물을 효과적으로 제거하기 위해 주 세정 매체인 $CO_2$의 수농도를 조절할 수 있는 Multi-Nozzle의 개발과 이로 인하여 세정력의 강도를 조절하도록 하였다. 세정 후 발생되는 오염입자를 효과적으로 제거하도록 국부 Exhaust를 Nozzle전단에 달아 재 오염의 방지효과를 극대화 시켰다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.06a
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• pp.11-14
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• 2018

본 논문에서는 실시간 고화질 360 영상 전송을 위해 사용자 시점에 기반한 타일 분할 기법을 적용하고 360 영상을 가상현실 기기 화면에 표현하여 주관적 화질 평가를 위한 플랫폼을 구현한다. 사용자 시점에 기반한 고화질 360 영상 전송을 위한 방안으로, 분할된 영상에서 전송되지 않은 영상으로의 움직임 참조 문제를 해결하기 위해 적용된 MCTS (motion constrained tile sets) 기술과 실시간으로 사용자 시점에 위치한 타일들만 추출할 수 있도록 미리 구성된 타일 정보들을 포함하는 EIS (extraction information sets) SEI, 사용자 시점에 위치한 타일 정보만 추출해내고 영상을 분할 및 추출해주는 Extractor, 실제 추출된 영상 정보를 이용해 가상현실 기기 화면에 표현하는 방법에 대한 구현 내용을 설명한다. 따라서 제안된 구현물을 기반으로 고화질 360 영상 전송을 수행하면, 사용자 시점 영역의 영상만 전송하여 불필요한 영상 전송을 하지 않게 되어 화질 대비 낮은 대역폭의 향상된 실시간 전송 영상을 얻을 수 있다.

• Journal of the Korea Concrete Institute
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• v.25 no.3
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• pp.321-329
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• 2013

Recently, the medium-low level radioactive waste from nuclear power plant must be transported from temporary storage to the final repository. Medium-low level radioactive waste, which is composed mainly of the liquid ion exchange resin, has been consolidated with cementitious material in the plastic or iron container. Since cementitious material is brittle, it would generate cracks by impact load during transportation, signifying leakage of radioactive ray. In order to design the safety transporting equipment, there is a need to check the compressive strength of the current waste. However, because it is impossible to measure strength by direct method due to leakage of radioactive ray, we will estimate the strength indirectly by the dynamic modulus of elasticity. Therefore, it must be identified the relationship between of strength and dynamic modulus of elasticity. According to the waste acceptance criteria, the compressive strength of cement based solid is defined as more than 3.44 MPa (500 psi). Compressive strength of the present solid is likely to be significantly higher than this baseline because of continuous hydration of cement during long period. On this background, we have tried to produce the specimens of the 28 day's compressive strength of 3 to 30 MPa having the same material composition as the solid product for the medium-low level radioactive waste, and analyze the relationship between the strength and the dynamic modulus of elasticity. By controling the addition rates of AE agent, we made the mixture containing the ion exchange resin and showing the target compressive strength (3~30 MPa). The dynamic modulus of elasticity of this mixtures is 4.1~10.2 GPa, about 20 GPa lower in the equivalent compressive strength level than that of ordinary concrete, and increasing the discrepancy according to increase strength. The compressive strength and the dynamic modulus of elasticity show the liner relationship.

• Journal of the Korean GEO-environmental Society
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• v.16 no.11
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• pp.13-19
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• 2015

Construction materials using soil which is the most common material around us have many advantages, but their long-term durability and sensation of walking as pavements have problems. Therefore, they are used after compaction or mixed with various hardening agents such as lime and cement for strength enhancement. However, studies on the behavior of pavement materials mixed with environment-friendly hardening agents or admixtures to improve walking property are still insufficient. In this study, therefore, in order to evaluate the appropriate mixing ratio and field application characteristics of pavement materials using mixed soils with environment-friendly hardening agents and natural materials such as wood chips, mechanical tests were performed to evaluate the rational mixing ratios and the ball test was performed as an elasticity test to evaluate the field applicability. The results suggest that the content of wood chips should be selected at 1.5% or lower according to the purpose of the structure, and the hardening agent at 10~15%. The evaluation results for GB/SB coefficient ratio which indicates the walking property show that the appropriate mixing ratio of the hardening agent in terms of the sensation of walking is 15% of lower, but different mixing ratios should be chosen according to the proportion of wood chips.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.1
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• pp.83-90
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• 2017

The pyroprocessing of spent nuclear fuel generates LiCl-KCl eutectic waste salt containing radioactive rare earth nuclides. It is necessary to develop a simple process for the treatment of LiCl-KCl eutectic waste in a hot-cell facility. In this study, capture and solidification of a rare earth nuclide (Nd) in LiCl-KCl eutectic salt using an inorganic composite with a $Li_2O-Al_2O_3-SiO_2-B_2O_3$ system was conducted to simplify the existing separation and solidification process of rare earth nuclides in LiCl-KCl eutectic waste salt from the pyroprocessing of spent nuclear fuel. More than 98wt% of Nd in LiCl-KCl eutectic salt was captured when the mass ratio of the composite was 0.67 over $NdCl_3$ in the eutectic salt. The content of $Nd_2O_3$ in the Nd captured-composite reached about 50wt%, and this composite was directly fabricated into a homogeneous and chemical resistant glass waste in a monolithic form. These results will be utilized in designing a process to simplify the existing separation and solidification process.

• Tunnel and Underground Space
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• v.22 no.1
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• pp.69-76
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• 2012

Theoretical backgrounds on the experimental methods of explosive welding, explosive forming and shock consolidation of powders are introduced. Explosive welding experiments of titanium (Ti) and stainless steel (SUS 304) plate were carried out. It was revealed that a series of waves of metal jet are generated in the contact surface between both materials; and that the optimal collision velocity and collision angle is about 2,100~2,800 m/s and $15{\sim}20^{\circ}$, respectively. Also, explosive forming experiments of Al plate were performed and compared to a conventional press forming method. The results confirmed that the shock-loaded Al plate has a larger curvature deformation than those made using conventional press forming. For shock consolidation of powders, the propagation behaviors of a detonation wave and underwater shock wave generated by explosion of an explosive are investigated by means of numerical calculation. The results revealed that the generation and convergence of reflected waves occur at the wall and center position of water column, and also the peak pressure of the converged reflected waves was 20 GPa which exceeds the detonation pressure. As results from the consolidation experiments of metal/ceramic powders ($Fe_{11.2}La_2O_3Co_{0.7}Si_{1.1}$), shock-consolidated $Fe_{11.2}La_2O_3Co_{0.7}Si_{1.1}$ bulk without cracks was successfully obtained by adapting the suggested water container and strong bonding between powder particles was confirmed through microscopic observations.

• Journal of Broadcast Engineering
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• v.15 no.4
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• pp.513-526
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• 2010

In this paper, we propose a de-blocking filter for improvement of coding efficiency and computational complexity reduction on a high definition video coding. Recently, the H.264/AVC standard-based research for high definition video coding method is under way because the amount of used of high definition videos is on the increase. The H.264/AVC de-blocking filter is designed for low bitrate video coding and it improves not only the subjective quality but also coding efficiency by minimizing the blocking artifact. However, the H.264/AVC de-blocking filter that strong filtering is performed is not suitable in a high definition video coding which occurs relatively low blocking artifact. Also, the conventional de-blocking filter has high computational complexity in decoder side. The computational complexity of the proposed method is reduced about maximum 8.8% than conventional method. Furthermore, the coding efficiency of the proposed method is about maximum 7.3% better than H.264/AVC de-blocking filter.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.2
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• pp.99-105
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• 2010

This paper investigated the characteristics of wasteform containing a spent zeolite used as a separating agent of FPs for recycling LiCl waste which would be generated from pyrochemical process of spent PWR fuel. In this study, a conventional borosilicate and Ca-rich glass were used as a consolidating agent for spent zeolite and it's mixing ratio was changed in the range, $25{\sim}35wt%$. The leach rates of Cs and Sr had about $0.1{\sim}0.01g/m^2day$ and $0.001{\sim}0.0001g/m^2day$, respectively. The leach resistance of Cs increased with amount of SAP and it showed about 10 times higher in the Ca-rich glass wasteform than in the conventional borosilciate glass wasteform. The compressive strength of wasteform was affected with the amount of glass. Thermal expansion rate of containing 30wt% glass has relatively lower than others. Also, the melting temperature was little changed in given mixing ratio of glass.