본 연구는 대기 중 장기간 노출로 인해 열화된 Ni-rich NCM811(LiNi₀.₈Co₀.₁Mn₀.₁O₂) 양극 소재의 계면 저항 증가 및 전기화학적 성능 저하 문제를 해결하기 위해, 물리적 열처리 방법을 제안하였다. NCM811 양극 소재는 대기 중 수분 및 이산화탄소와의 반응에 의해 표면에 불순물이 형성되기 쉬우며, 이는 고체전해질과의 계면 저항을 증가시켜 전고 체전지 시스템에서의 성능 저하를 초래한다. 이러한 문제를 해결하기 위해, 열화된 NCM811 양극 소재를 O₂ 분위기 에서 열처리하여 표면의 불순물을 효과적으로 제거하고 양극 표면의 전도성을 향상시킴으로써, 양극-고체전해질 간의 계면 저항을 현저히 감소시키는 결과를 얻었다. SEM, XRD, ICP 분석을 통해 열화된 NCM811 양극 소재의 표면 특성 변화를 분석하였으며, 열처리 후 NCM811 소재의 계면 특성이 개선됨에 따라 전기화학적 성능 또한 상용 NCM811 소재와 유사한 수준으로 회복되는 것을 확인하였다. 특히, O₂ 분위기의 물리적 열처리 방법은 Ni-rich NCM811 양극 소재의 열화를 효과적으로 억제하고 고체전해질과의 계면 접촉을 개선하여, 황화물계 전고체전지의 전기화학적 성능 을 획기적으로 향상시킬 수 있는 유망한 기술임을 입증하였다. 이러한 결과는 전고체전지 상용화를 위한 핵심 전략으 로 적용될 수 있을 것으로 기대된다.

In this study, a bipolar visible light responsive photocatalytic fuel cell (PFC) was constructed by loading a Z-scheme g-C3N4/ carbon black/BiOBr and a Ti3C2/ MoS2 Schottky heterojunction on the carbon brush to prepare the photoanode and photocathode, respectively. It greatly improved the electron transfer and achieved efficient degradation of organic pollutants such as antibiotics and dyes simultaneously in two chambers of the PFC system. The Z-scheme g-C3N4/carbon black/BiOBr formed by adding highly conductive carbon black to g-C3N4/BiOBr not only effectively separates the photogenerated carriers, but also simultaneously retains the high reduction of the conduction band of g-C3N4 and the high oxidation of the valence band of BiOBr, improving the photocatalytic performance. The exceptional performance of Ti3C2/ MoS2 Schottky heterojunction originated from the superior electrical conductivity of Ti3C2 MXene, which facilitated the separation of photogenerated electron–hole pairs. Meanwhile, the synergistic effect of the two photoelectrodes further improved the photocatalytic performance of the PFC system, with degradation rates of 90.9% and 99.9% for 50 mg L− 1 tetracycline hydrochloride (TCH) and 50 mg L− 1 rhodamine-B (RhB), respectively, within 180 min. In addition, it was found that the PFC also exhibited excellent pollutant degradation rates under dark conditions (79.7%, TCH and 97.9%, RhB). This novel pollutant degradation system is expected to provide a new idea for efficient degradation of multiple pollutant simultaneously even in the dark.

The concrete structure of a nuclear power plant is a major safety structure that performs shielding functions to block radioactive materials and radiation, heat removal, and isolation functions. Therefore, concrete structures of nuclear power plants must prove structural safety from immediately after construction to dismantling, and a representative method for this is to investigate compressive strength. The compressive strength and specimen standards of concrete structures are specified in ASTM C 42/C 42M, and samples must be obtained through core drilling in order to collect samples according to this standard. However, commercial equipment requires anchor installation work causes radiation dust generation. Even commercial products have developed equipment that does not require anchor installation work, but it can only be applied to flat walls and cannot be applied to curved walls such as bioshields. To solve this problem, a method of fixing to the scaffolding pipe was designed. The equipment developed based on this method fundamentally blocks the generation of radioactive dust. The vertical position can be adjusted using guide shafts and jack screws, and the horizontal position can be adjusted using scaffolding clamps. In addition, the distance between the installation location and the wall can be adjusted by adjusting the scaffolding clamp location of the device. Lastly, it can be rotated to the left and right, so that even on a curved wall, the sampling position can be performed perpendicular to the wall. Core drills that take specimens for measuring compressive strength use the wet type. Core drilling by wet type in radioactively contaminated concrete leads to the disposal of sludge as radioactive waste. Water supplied during core drilling is scattered in all directions by the rotation of the core drill bit, which causes radiation exposure to workers, so measures must be taken to ensure that the water does not splash and gather in one place. Nileplant Co., Ltd. has developed a sludge collection device that can be used with a core drilling device. It can be inserted into a 4-inch core drill bit to meet the specimen regulations of ASTM C 42/C 42M, and nylon resin was used as a material to withstand friction with water, and the wall of the drainage part was thickened to increase durability. Based on these results, it is expected to be able to work more quickly and safely when collecting core drilling samples of radioactively contaminated concrete or radiation and concrete.

This study considers the proper repair techniques by examining the most representative repair cases of the Korean arch bridges and proposes the constructional manual which can apply similar occasions. The cases are Seonamsa Seungseongyo and Songgwangsa Geukrockgyo where this researcher had taken part in the repair works. This Study proposes the maintenance construction manual about the performance degradation drew by performance degradation of the both Korean arch bridges in the maintenance process. First, arch bridge maintenance should be carried out in the dry season, when water is impermeable in the bottom surface of the bridge. Moreover, risk factors of the maintenance should be excluded to secure the water vally flow, the bypass and the temporary bridge. Second, prior to repair, it has to precede ①3D shooting ② formal examination ③structure safety test ④geological and lithic surveys ⑤arch curvature establishment and makeshift frame settlement before transformation ⑥relationship expert comments. Third, if the baduk and the foundation stones are inevitable to replace due to performance degradation on the foundation, it should use the high quality stones and secure greater stress by extending the standard range. The foundation on irregular rock needs to be flattened and underside on the replaced materials require Grengyijil to deliver the equal loads. Fourth, In the process of dismantling the stones of the arched bridge, it could make heavy weathering degree and not reuse the materials. Charge should converge the expert advices to choose the reuseable, the conservate and the alternative materials, and increase the reutilization of the raw materials by preservation and reinforcement treatments. Fifth, the side wall should be repaired by the rubble work technique which is not able to pile compost satiety, so it must use long depth of masonary stones for reinforcement. It is considered to reinforce the stone wall in shore as much as possible and protect the abutment and the side wall on the upstream for the arch bridge maintenance works.

본 연구에서는 연료극 또는 공기극에 함유된 불순물인 황화합물의 도입을 차단할 수 있는 GDL을 제조하여, 이를 평가용 단위전지에 체결하여 H2S와 SO2를 연료극과 공기극에 각각 동시에 공급하여 PEMFC의 성능 저하 및 회복에 관한 연구를 수행하였다. 그 결과 H2S와 SO2의 농도가 증가함에 따라 전지의 성능이 감소하며 특히 10 ppm 이상의 농도에서는 10분 이내에 약 10-15% 정도 성능이 감소하였다. 특히 GDL 표면의 기공이 없는 CN-2 GDL을 체결한 단위전지의 경우 피독에 의한 성능 감소 속도가 더 빠른 것을 확인하였다. 그리고 단위전지 피독 후 황화합물이 혼합되지 않은 순수 가스를 1시간 이상 공급하였을 때 전지의 성능이 GDL의 종류에 따라 90%에서 95% 이상 회복되며 CN-1 GDL의 경우가 가장 회복이 우수하였다.

This study investigated the treatment of acetaminophen in municipal wastewater by conventional ozonation, ozone-based advanced oxidation, ozone/UV, and the electro-peroxone process. The ozone/UV process and electro-peroxone process of electric power consumption increased 1.25 and 2.04 times, respectively, compared to the ozone process. The pseudo-steady OH radical concentration was the greatest in the　electro-peroxone process and lowest in the ozone process. The specific energy consumption for TOC decomposition of the ozone/UV process and electro-peroxone process were 22.8% and 15.5% of the ozone process, respectively. Results suggest that it is advantageous in terms of degradation performance and energy consumption to use a combination of processes in municipal wastewater treatment, rather than an ozone process alone. In combination with the ozone process, the electrolysis process was found to be more advantageous than the UV process.

This study provides a simple introduction to photo-catalyst technology to self-clean the organic dirts and degrade the air pollution in urban environment. Moreover, it shows the spray coating technique was applied to effective coating on the surface of concrete specimen by using as-developed integral photocatalyst solution. In order to examine photo-catalytic activity and degradation effectiveness on the surface of the concrete specimen, the UV-LED lamp was used as a light source to activate the photo-catalysis. Methyl-orange dye was used as an indicating method to speculate the photo-catalytic reaction and UV-VIS spectrometer to determine the molar content of the organic dye.

This study presents the investigation for relationship between local damage and structural performance of the 7-wire strand. This strand is often used additional reinforcement of bridges such as PSC (Prestressed Concrete) bridge and cable-stayed bridge. Stay cables are continuously damaged after completion and corrosion is the main cause of damage. Due to its structural characteristics, it is difficult to quantitatively evaluate the degradation cable damage. Therefore the relationship between local damages on strand and structural performance is experimentally and analytically evaluated in this study. The results can be used for the safety management of the cable supported bridges in the future.

자연 환경의 영향에 의해서 선명한 영상정보를 수신하지 못할 경우 정밀한 알고리즘도 한계가 발생한다. 이러한 한계를 극복하기 위해서 다양한 CCTV카메라를 통해 자연환경 조건인 바람, 안개, 야간에 대해 테스트를 수행하여 수위감지에 가장 적절한 카메라를 선택하는 것이 수위 알고리즘 감지 성능을 향상 시킬 수 있다. 자연환경에 대한 성능저하 방지대책으로 하드웨어와 소프트웨어적인 방지대책을 보면, 먼저 H/W적인 영상보정방법으로는 Stabilizer 추가 장착, Defog 장비 추가 장착 및 Day&Night와 근적외선 카메라 설치 등 장비를 통한 바람, 안개, 야간 환경에 대한 보정방법이 있으며, S/W방법은 Stabilizer에 의한 바람에 대한 보정방법과 Defog에 의한 안개보정 그리고 DSS(Digital Slow Shutter)에 의한 야간 조도의 보정방법이 있다. 첫 번째, 바람에 대한 영상보정 방법으로 폭풍이나 바람이 심하게 불 때 카메라의 떨림에 의해서 영상을 분석하는데 성능이 떨어지게 된다. 이러한 문제를 해결하기 위해 Stabilizer를 이용한 방법으로 하드웨어 영상보정기를 추가하여 영상의 흔들림을 보정해주는 방법과 흔들림 보정 알고리즘을 소프트웨어적으로 전처리에 의한 지능형 영상분석처리를 통한 전·후 영상으로 성능을 개선한다. 두 번째, 하천의 경우 안개가 발생하여 수위감지 성능에 영향을 줄 수 있다. 소프트웨어적으로는 Defog 기능을 구현하여 영상분석 전처리로 안개의 영상을 제거하고, 하드웨어적으로는 가시광선 영역보다는 파장이 길어 안개의 영향을 덜 받는 근적외선 카메라를 통해 좋은 품질의 영상을 획득 할 수 있다. 마지막으로 야간의 경우 조도가 약해지므로 수위감지 알고리즘에 영향을 미치게 된다. 이러한 문제를 개선하기 위해서는 물리적으로 조명을 비춰주는 방법이 있으나, 추가 설비가 필요하며 구축비용 및 전략 소모가 된다. 현재 대부분의 카메라에 DSS(Digitla slow shutter)라는 기능이 있어 조도가 약한 경우 Framerate를 낮추어 일정 수준의 이미지를 캡쳐가 가능하다. 수위감지 알고리즘의 경우 긴 시간동안의 물의 변화량을 관측하는 것으로 Framerate에 크게 영향을 받지 않으므로 DSS 기능을 통해 조도의 영향을 보상할 수 있다. 본 연구의 결론은 Day&Night 카메라에 근적외선 영역만을 받아들일 수 있도록 Filter를 사용하여 가시광선에서의 안개에 의한 영향을 줄이고, DSS를 이용하여 조도가 부족한 야간 환경에서 셔터의 스피드를 줄여 선명한 이미지를 가져 오도록 한다. 이와 같은 설정을 통해 선명한 이미지를 받아 수위감지 알고리즘의 성능을 향상시킬 수 있다고 판단된다.