본 발표에서는 고분자막의 열화(Degradation)원인과 열화 조건, 열화방지 방법, 고분자막 내구성 평가 방법 등에 대해서 논의하고자 한다. PEMFC 고분자 막의 열화원인은 전기화학적인 열화를 포함한 화학적인 열화와 물리적인 열화, 열에 의한 열화로 분류할 수 있다. 고분자 막이 전기화학적열화가 잘되는 조건은 OCV와 같은 높은 전압, 저 가습, 고온, 높은 수소/산소 압력 조건이다. 고분 자막의 내구성을 평가하기 위해서 열화 가속화 기법을 사용하는데, 전기화학적 내구성은 OCV holding 기법을, 물리적 내구성은 Wet/Dry 기법을 일반적으로 사용한다. 이들 내구성 평가 방법에 관한 미국의 DOE 프로토콜과 일본의 NEDO 프로토콜을 비교 검토한다.

북한의 산림 황폐화는 매우 심각한 것으로 보고되고 있으 며, 이를 해결하기 위해 황폐화 방지와 온실가스 감축을 목 표로 한 REDD+ 사업에 대한 관심이 높아지고 있다. 본 연 구에서는 북한 황해북도에서 10,000 ha를 대상지에 대해 다 중시기 토지피복 변화를 분석하였다. 연구 대상지의 산림 황 폐화는 계속 심해져, 1989년 7,035 ha로부터 2013년 4,293 ha로 약 39%가 감소하는 것으로 나타났다. 그에 따라 산림 탄소축적량은 약 284,399 tCO2 감소한 것으로 나타났다. 기 준선을 설정하고 REDD+ 사업에 의한 산림탄소 감소방지 량 (온실가스배출감축량)을 분석한 결과 약 364,704 tCO2가 감소하지 않고 유지될 수 있는 것으로 나타났다. 현장조사 수행이 불가능한 한계점과 단위면적 (ha)당 산림탄소축적량 을 이용할 시 북한의 수종 재적 자료가 없는 제한 하에 남한 의 자료를 사용한 한계는 향후 극복하여야 할 과제라고 판 단된다. 그러나 본 연구는 향후 북한에서 REDD+ 사업을 위 해 활용될 수 있을 것이다.

The present in vitro study was conducted to examine the effect of buffer solubility of eight protein feeds (coconut meal, distillers grain, sesame meal, perilla meal, soy source cake, rape seed meal, soybean meal and lupine) on the fermentation characteristics, degradability of dry matter (DM) and crude protein (CP), and methane (CH4) production by rumen microbes. Buffer extraction increased pH (P<0.05 ~ p<0.001) of the culture solution but tended to lower ammonia- N concentration for all protein feeds. Total volatile fatty acids(VFAs) and each VFAs concentrations in all incubation was decreased by buffer extraction (P<0.01 ~ P<0.001). Also, molar proportion of acetate in 1h (P<0.001), 3h (P<0.01) and 12h (P<0.05) incubations and molar proportion of propionate in 1h (P<0.001), 3h (P<0.01), 6h (P<0.05) and 12h (P<0.05) were decreased by buffer extraction. But molar proportion of butyrate in 1h (P<0.001), 3h (P<0.01) and 6h (P<0.05) were increased by buffer extraction. The in vitro effective degradability of dry matter (P<0.001) and CP (P<0.001) was decreased by buffer extraction. The methane production (P<0.01~P<0.001) in all incubation was decreased by buffer extraction. The results from in the current study might be useful for diet formulation to improve the feed efficiency of the ruminant animals without massive loss of major nutrients.

SnS-TiO2 nanocomposites are synthesized using simple, cheap, and less toxic SnCl2 as the tin (II) precursor. The prepared nanoparticles are characterized using powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and UV-Vis diffuse reflectance spectra (DRS). The XRD and TEM results indicate that the prepared product has SnS nanoparticles and a grain diameter of 30 nm. The DRS demonstrate that SnS-TiO2 possesses the absorption profile across the entire visible light region. The generation of reactive oxygen species is detected through the oxidation reaction from 1,5-diphenyl carbazide (DPCI) to 1,5-diphenyl carbazone (DPCO). It is found that the photocurrent density and photocatalytic effect increase with the modified SnS. Excellent catalytic degradation of Texbrite BA-L (TBA) solution is observed using the SnS-TiO2 composites under visible light irradiation. It is proposed that both the strong visible light absorption and the multiple exciton excitations contribute to the high visible light photocatalytic activity.

태양전지는 태양복사에너지를 반도체의 광전효과를 통해 전기에너지로 변환시키는 친환경 에너지변환장치를 의미한다. 수분을 포함하는 다양한 화학물질들에 대한 높은 차단성을 갖는 다층형 필름인 백시트는 태양전지의 중요한 요소이다. 대표적인 백시트는 polyvinyl fluoride (PVF)와 poly(ethylene terephthalate) (PET)의 다층필름으로 구성된다. PVF는 높은 내후성을 가지는 반면, 가격이 상대적으로 비싼 단점을 보인다. 따라서, 백시트의 제조가격을 낮출 수 있으면서, 동시에 실제 태양전지모듈에 적용할만한 수명특성을 만족시킬 수 있는 대체소재의 개발이 필수적이다. 본 연구에서는 일정수준의 결정성을 갖는 PET 필름을 PVF 필름 대신 사용하였다. 그러나, PET 소재는 다양한 pH 조건에서 trans-esterification 및 가수분해에 의해 분해될 수 있기 때문에, 태양전지의 구동조건에서 PET의 분해거동을 이해할 필요가 있다. 단시간 내 화학적 분해거동을 평가하기 위해서, 가속화된 PET 분해실험 프로토콜이 개발되었다. 마지막으로, 제안 개념의 효용성은 태양전지모듈의 장기운전성능 평가를 통해 확인하였다.

본 연구는 위성영상 자료와 래스터 연산을 활용해 인도네시아 깜빠르 지역에서 REDD 이행 시 필요한 탄소배출 기준선 설정에 주된 목적을 둔다. REDD (Reducing Emissions from Deforestation and forest Degradation)는 개도국의 개발활동에 의한 산림황폐화를 막기 위해 산림유지에 대한 대가로 탄소배출권을 발행하는 국제환경보전정책이다. ‘기준선’은 REDD가 이행되지 않았을 때 잠재적으로 발생할 미래의 탄소배출량을 의미한다. 이는 탄소배출권 규모를 결정짓는 중요한 요소이기 때문에 REDD 사업 경제성과 밀접한 관계가 있다. Landsat 영상에 기반해 토지이용 및 피복을 분류하였고, 기 구축된 바이오매스 지도와 세 가지 토지이용 시나리오를 적용해 기준선을 설정하였다. 그 결과, 연구지역은 산림황폐화로 인한 탄소 유실이 산림전용으로 인한 유실보다 더 큰 것으로 밝혀졌다. 본 연구에서 개발한 기준선 설정 방법론은 국제적으로 공인 받은 REDD 가이드라인을 응용하여 설계하였기 때문에 실제 REDD 이행 시 유용할 것이라 예상된다.

Cubic mesocrystal CeO2 was synthesized via a hydrothermal method with glutamic acid (C5H9NO4) as a template. The XRD pattern of a calcined sample shows the face-centered cubic fluorite structure of ceria. Transmission electron microscopy (TEM) and the selected-area electron diffraction (SAED) pattern revealed that the submicron cubic mesocrystals were composed of many small crystals attached to each other with the same orientation. The UV-visible adsorption spectrum exhibited the red-shift phenomenon of mesocrystal CeO2 compared to commercial CeO2 particles; thus, the prepared materials show tremendous potential to degrade organic dyes under visible light illumination . With a concentration of a rhodamine B solution of 20 mg/L and a catalyst amount of 0.1 g/L, the reaction showed higher photocatalytic performance following irradiation with a xenon lamp (≥ 380 nm). The decoloring rate can exceed 100% after 300 min.

The degradation characteristics of perchloroethylene by ferrate(VI) oxidation have been studied. The degradation efficiency of perchloroethylene in aqueous solution was investigated at various values of ferrate(VI) dosage, pH, initial concentration of perchloroethylene and aqueous solution temperature. GC-ECD has been used to analyze the changes of perchloroethylene concentration. The optimum conditions of perchloroethylene degradation were obtained at pH 7.0 and 25°C of aqueous solution temperature. Also, the experimental results showed that perchloroethylene removal efficiency increased with the decrease of initial concentration of perchloroethylene. Lastly intermediate products were identified by GC-MS techniques. Trichloroethylene and chloroform were identified as reaction intermediates.

본 연구는 옥수수 사일리지를 이용하여 TMR 제조 시 배합시간에 따른 물리적 특성(Particle size, peNDF 및 laceration)의 변화를 조사하고, 반추위 내 in situ 건물분해율 및 비유중기 착유우의 유생산성에 미치는 영향을 조사하고자 수행되었다. TMR 시험사료는 동일한 원료를 이용하여 배합시간을 30분(T1구)과 50분(T2구)으로 제조하였다. Penn State Particle Size Separator (PSPS, 19 mm와 8mm 체)로 분리하여 입자크기의 분포를 분석한 결과 배합 시간이 30분(T1)에서 50분(T2)로 증가함에 따라 하층(<8mm)의 비율이 유의적으로 증가하였고(p<0.01), peNDF>8.0는 유의적으로 감소하였으며(p<0.01), 굵은 비율(≥1mm) 이 유의적으로 감소하였다(p<0.01). 반추위 내 in situ 건물 분해율은 모든 배양시간에서 처리구간 차이가 없었지만 24시간 배양에서 T1구에서 유의적으로 높게 나타났다. (p<0.01). 산유량은 처리구간 차이가 없었지만 유지방은 T1이 유의적으로 높게 나타났다(p<0.01). 본 연구 결과에서 옥수수 사일리지 위주의 TMR 제조 시 배합시간을 단축 조절함으로서 산유량 및 유성분에 대한 부정적 영향 없이 조사료의 물리적 사료가치를 증진하는데 효과가 있을 것으로 기대된다.

This study was conducted to examine the effects of defaunation (removal of live protozoa) on fermentation characteristics, degradation of ryegrass hay and CH4 (methane) production by rumen microbes when incubated with plant oils (SO, sunflower oil and LO, linseed oil) in vitro. Sodium lauryl sulfate (0.000375 g/ml) as a defaunation reagent was added into the culture solution and incubated anaerobically up to 24 h at 39℃. pH from defaunation was increased for all treatments from 6 h incubation times (p<0.01-0.001) compared with those from fauantion. Concentration of ammonia-N from defaunation is higher than that from faunation at 3 h (p<0.001), 12 h (p<0.05) and 24 h (p<0.001) incubation times. Defaunation decreased (p<0.01-0.001) total volatile fatty acid concentration at all incubation times. Molar proportions of C2 (acetate, p<0.05-0.001) and butyrate (p<0.01-0.001) were also decreased by defaunation at all incubation times. Molar proportion of C3 (propionate), however, was increased by defaunation at all incubation times (p<0.001). Thus the rate of C2 to C3 was decreased by defaunation at all incubation times (p<0.001). Defaunation decreased ED (effective degradability) of dry matter (p<0.001) and ED of neutral detergent fiber (p<0.001) of ryegrass hay. Defaunation decreased total gas, CH4 production, CH4 % in total gas and CH4/CO2 at all incubation times (p<0.001). Oil supplementation decreased total gas (p<0.05-0.001), CH4 production (p<0.001) and CH4 % in total gas (p<0.001) compared with control at all incubation times. The result of this study showed that defaunation combined with oil supplementation may cause an alteration of microbial communities and further medicate the fermentation pattern, resulting in both reduction of degradation of ryegrass hay and CH4 production. No difference, however, was observed in all the examinations between SO and LO.

The use of solar energy generation is steadily increasing, and photovoltaic modules are connected in series to generate higher voltage and power. However, solar panels are exposed to high-voltage stress (up to several hundreds of volts) between grounded module frames and the solar cells. Frequent high-voltage stress causes a power-drop in the modules, and this kind of degradation is called potential induced degradation (PID). Due to PID, a significant loss of power and performance has been reported in recent years. Many groups have suggested how to prevent or reduce PID, and have tried to determine the origin and mechanism of PID. Even so, the mechanism of PID is still unclear. This paper is focused on understanding the PID of crystalline-silicon solar cells and modules. A background for PID, as well as overviews of research on factors accelerating PID, mechanisms involving sodium ions, PID test methods, and possible solutions to the problem of PID, are covered in this paper.

When sunlight irradiates a boron-doped p-type solar cell, the formation of BsO2i decreases the power-conversion efficiency in a phenomenon named light-induced degradation (LID). In this study, we used boron-doped p-type Cz-Si solar cells to monitor this degradation process in relation to irradiation wavelength, intensity and duration of the light source, and investigated the reliability of the LID effects, as well. When halogen light irradiated a substrate, the LID rate increased more rapidly than for irradiation with xenon light. For different intensities of halogen light (e.g., 1 SUN and 0.1 SUN), a lower-limit value of LID showed a similar trend in each case; however, the rate reached at the intensity of 0.1 SUN was three times slower than that at 1 SUN. Open-circuit voltage increased with increasing duration of irradiation because the defect-formation rate of LID was slow. Therefore, we suppose that sufficient time is needed to increase LID defects. After a recovery process to restore the initial value, the lower-limit open-circuit voltage exhibited during the re-degradation process showed a trend similar to that in the first degradation process. We suggest that the proportion of the LID in boron-doped p-type Cz-Si solar cells has high correlation with the normalized defect concentrations (NDC) of BsO2i. This can be calculated using the extracted minority-carrier diffusion-length with internal quantum efficiency (IQE) analysis.

Trametes versicolor showed the ability of degrading synthetic dyes such as congo red (CR) and methylene blue (MB) in solid and liquid culture conditions. The T. versicolor strains isolated in Korea degraded MB more efficiently than CR, differently most of other white mushrooms known to have difficulties in degrading MB than other dyes. Thus the Koren strains of T. versicolor showed the commercial potential to be used for cleaning dye-contaminated region without any patent-related problem. The main enzyme responsible for dye deradation was laccase. The manganese peroxidase (MnP) was also detected and supposed to be involved in the degradation process of synthetic dyes. However, no lignin peroxidase (LiP) was detected from degradation process, indicating LiP is not the enzyme T. versicolor use to degrade CR and MB.

To inject CO2 in geological formations, deep wells that penetrate the formations need to be constructed. The seal integrity of deep wells for CO2 leakage are enhanced by annulus cements. By injecting CO2, brine in formations can be carbonated and the potential degradation of annulus cement in the carbonated brine has been brought up. In this paper, Type G oil well cement (OWC) pastes are hydrated for 28 days. Conditions of geosequestration in a sandstone formation at a depth of roughly 1 km, was simulated by bubbling CO2 into a heated vessel containing brine. The hydrated OWC cylindrical specimens were exposed to this environment. Slices of the cement specimen were taken periodically, during and after exposure to quantify degradation progression. The elastic modulus of the specimens was examined prior to and after exposure. After 28 days of exposure, the degraded depth of specimen was measured as 4.137 mm. The elastic modulus of the specimens was measured as 2.2 GPa and 3.2 GPa prior to and after exposure respectively. Considering a composite action in the partially degraded specimen, the elastic modulus of degraded part can be extracted. The results indicated that the difference of elastic modulus in the partially degraded annulus cements could occur a composite action of deep wells subject to axial load and shear cracks would be generated due to the composite action.

본 연구는 조사료의 반추위 발효가 진행됨에 따른 볏짚 표면에 부착된 섬유소 분해 박테리아의 군집변화와 섬유소 소화율을 비교 관측하기 위하여 볏짚의 in situ 반추 발효를 실시하였다. 그리고 부착 박테리아의 군집 변화를 측정하기 위하여 RT-PCR 기법을 이용하여 F. succinogenes. R. albus와 R. flavefaciens의 군집을 모니터링 하였다. 본 연구를 수행하기 위하여 in situ 볏짚 발효를 0. 2, 4, 8, 12, 24시간 실시하였을 때 반추위내 볏짚의 in situ 분해는 발효 시간이 진행됨에 따라 가속화되어 발효 8~12시간 사이에 최고 분해 속도를 나타내었으나, F. succinogenes, R. flavefaciens과 R. albus는 모두 발효 0~1시간 사이에 볏짚 표면에 부착이 80% 이상 완료되어 이후 발효가 계속 진행되는 동안 일정 수준의 군락을 유지하는 것이 발견되었다. 그리고 반추위내 유입된 조사료의 표면에 초기 부착 과정을 관찰하기 위하여 0, 5, 10, 30 및 60분 간격으로 볏짚의 in situ 샘플을 채취하여 조사하였을 때 F. succinogenes, R. flavefaciens 및 R. albus의 군락 모두 볏짚이 반추위 유입 후 5분 내에 상당량의 수가 부착함을 발견하였다. 또한 조사료의 반추위 발효 용이성에 따른 섬유소 분해 박테리아의 부착 정도를 관찰하기 위하여 0, 2, 4 및 8% NaOH를 처리한 볏짚을 12 및 24시간 in situ 배양 볏짚의 소화율과 부착 박테리아의 군집 변화를 관측하였을 때, 볏짚의 NaOH 처리 농도가 높아짐에 따라 in situ 소화율이 증가하였으며, 동시에 부착된 박테리아 군집의 증가 경향이 F. succinogenes, R. flavefaciens 및 R. albus의 3균주 모두 배양 12시간에 나타났으나 배양 24시간에서는 각기 다른 양상을 나타냈다.따라서 본 연구결과는 반추위내 섬유소 발효과정에서 섬유소 분해 박테리아의 부착은 조사료의 반추위 유입 초기에 반드시 이루어지고, 발효 시간이 진행됨에 따라 조사료 표면에 안정된 군락을 형성하며, 섬유소 분해가 가속화된다는 사실을 보여 주었다.

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.

In the present work, WO3 and WO3-TiO2 were prepared by the chemical deposition method. Structural variations, surface state and elemental compositions were investigated for preparation of WO3-TiO2 sonocatalyst. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and transmission electron microscopy (TEM) were employed for characterization of these new photocatalysts. A rhodamine B (Rh.B) solution under ultrasonic irradiation was used to determine the catalytic activity. Excellent catalytic degradation of an Rh.B solution was observed using the WO3-TiO2 composites under ultrasonic irradiation. Sonocatalytic degradation is a novel technology of treating wastewater. During the ultrasonic treatment of aqueous solutions sonoluminescence, cavitaties and "hot spot" occurred, leading to the dissociation of water molecules. In case of a WO3 coupled system, a semiconductor coupled with two components has a beneficial role in improving charge separation and enhancing TiO2 response to ultrasonic radiations. In case of the addition of WO3 as new matter, the excited electrons from the WO3 particles are quickly transferred to TiO2 particle, as the conduction band of WO3 is 0.74 eV which is -0.5 eV more than that of TiO2. This transfer of charge should enhance the oxidation of the adsorbed organic substrate. The result shows that the photocatalytic performance of TiO2 nanoparticles was improved by loading WO3.

면진장치는 상부구조물의 지진력을 감소시키는데 크게 기여하지만, 고감쇠고무 적층받침에 사용되는 고무재료는 시간이 경과함에 따라 열화되어 상부구조물의 동특성과 기기들의 지진응답에 영향을 줄 수 있다. 따라서 면진장치의 경년열화를 고려한 구조물의 지진응답을 분석하는 연구가 필요하다. 본 연구에서는 기존 문헌을 통하여 분석된 고무의 경년열화 특성을 사용하여 면진장치를 모델링하였다. 면진된 원전의 지진응답을 평가하기 위하여 격납건물과 보조건물을 대상 구조물로 선정하고, 진동수 성분이 다양한 입력지진동을 사용하여 구조물의 고유진동수, 최대지진응답, 층응답스펙트럼을 시간의 경과에 따라 분석하였다. 해석결과에 의하면 면진장치의 경년열화에 의하여 지진응답이 소폭 증가하였으며, 면진장치가 설치된 후 20년까지 지진응답의 증가율이 크게 나타나므로 이 기간에 상세한 검사가 시행되어야 할 것이다.

This study was carried out to clarify the response of butterfly communities on forest degradation in the Gwangneung Forest, Korea. We monitored butterfly communities with varying degrees of human activities by conducting line transect twice a month in 2011. A total of 70 species and 4,676 individuals butterflies were observed in four sites: natural forest, plantation forests, and Korean National Arboretum. Species richness increased with increasing open land. The result on niche breadth and habitat type of butterfly was consistent with our predictions; specialist species and forest interior species were abundant in natural forest, whereas generalist species and grassland species were abundant in Korea National Arboretum, the most modified area. Also, habitat breadth of butterflies clearly indicated the difference on the degree of forest degradation. Butterfly diversity associated with landscape patterns based on aerial photographs supported mosaic concept which indicates that species diversity increases as habitat heterogeneity and variability increase. Forest management plan that maintains various habitats and ensures grasslands is necessary to increase butterfly diversity in forest.