This study was conducted to analyze the effects of stand density on fire fuel (FF) changes in a Chamaecyparis obtusa forest. The study site was located in Mt. Munsu in Jeollabuk-do and consisted of a control, 30% thinning treatment (LT), and 50% thinning treatment (HT). Three-year-old seedlings were planted at a density of 3,000 trees ha-1 in 1976, and thinning was carried out in 2000. FF production was measured every 2 months by installing 3 circular litter traps 1.2 m above the ground. Litter bags containing 5 g of each leaf and branch were made and buried in the organic layer to investigate the FF decomposition rate. The decay constant was calculated after 18 months. FF accumulation was measured by collecting dry-weight organic matter from each plot using a square frame (0.09 m2) in September 2018. The FF production in LT and HT was significantly lower than that of the control (P<0.001). The leaf decay constant for HT was significantly lower than that of the control (P<0.05). The FF accumulation in HT was significantly lower than that of the control (P<0.01), but LT was not significantly different from the control. The results of this study showed that thinning decreased FF production.

기존의 바나듐 레독스 흐름전지(vanadium redox flow battery, VRFB)에서 사용하고 있는 과불소계이오노머인 나피 온(Nafion)은 전해질에 존재하는 바나듐 이온의 투과도가 높아, 바나듐 이온이 분리막을 투과하여 반대쪽 전해질로 교차 이동 하는 문제를 갖고 있다. VRFB에서 바나듐 이온의 투과는 서로 다른 산화수를 갖는 바나듐 이온이 부반응을 일으켜 충전, 방전 용량의 감소를 야기하고, 장기적인 성능 감소를 일으키는 원인이 된다. 이러한 문제를 해결하기 위해 본 연구에서는 SiO2에 3-aminopropyl group이 도입된 나노입자(fS)를 Nafion에 분산시켜 바나듐 이온의 투과를 감소시키고, VRFB의 장기적인 성능 의 향상을 도모하고자 하였다. SiO2에 붙어 있는 아민기(-NH2)가 Nafion의 술폰산 음이온(SO3 -)과 이온결합을 형성함과 동시 에, 암모늄 양이온(-NH3 +)의 양전하가 바나듐 이온에 대해 Gibbs-Donnan 효과를 나타내어 낼 것이라고 기대하였다. fS를 섞은 Nafion 용액의 pH와 Nafion-fS 막의 IEC 측정을 통해 암모늄 양이온과 술폰산 음이온의 이온결합이 존재하는 것을 확인하였고, fS의 양이 많아질수록 바나듐 이온의 투과도가 감소하는 것을 확인하였다. VRFB 단위 전지에 제조한 복합막을 도입하였을 때, 150 mA/cm2의 전류밀도에서 충방전 사이클을 200회 반복 진행하여도 방전용량을 최대 80%까지 유지할 수 있었다.

Oral galvanism is known to induce chronic irritation on oral mucosa, but the related pathology rarely occurs. A 65 years old male complained of linear horizontal ulcerations on his bilateral buccal mucosa for one month. The oral ulcerations were parallel and approximated to his occlusal plane. He had multiple metallic crowns using gold and nickel cobalt alloy at bilateral upper and lower molar teeth, and also had accustomed to heavy smoking for more than twenty years. Biopsy examination was performed with immunohistochemical staining using antisera of PCNA, D2-40, and PARP. The epithelial ulcer had clear margin and was replaced by granulation tissue containing many dilated lymphatic vessels, which were positive for D2-40, but showed no feature of pseudo-necrotic membrane. Nearby epithelium showed the typical features of leukoedema, characterized by edematous keratinocytes with clear cytoplasms and pyknotic nuclei, low rete ridges, and rough superficial epithelial layer, where PCNA was rarely positive. Some superficial edematous keratinocytes showed perinuclear cytoplasmic vacuolization, and their peripheral nuclear chromatins were positive for PARP. Taken together, the present mucosa ulceration was different from aphthous stomatitis, herpes stomititis, oral lichen planus, etc., thus it was postulated that the galvanic current generated from between the upper and lower dissimilar metal crowns could affect the precedent leukoedema caused by heavy smoking habit and produce the linear horizontal buccal ulceration. Therefore, the present case was diagnosed as galvanic mucositis associated with leukoedema, and it was also hypothesized that the mild and persistent galvanic current was able to deplete the cytoplasmic fluid of leukoedema keratinocytes via the osmotic pressure difference elicited by increased ionic concentration of galvanism, and followed by severe keratinocyte apoptosis and oral mucosa ulceration.

In this study, a numerical research has been conducted to investigate the fire resistance performance of prestressed hollow-core slabs, in which the number of prestressing strands and the load ratio were set as the analysis parameters. Based on the numerical simulation results, the temperature distribution and deflection according to the fire duration time were analyzed in detail.

GAP 인증제도 도입초기의 시기적 필요성을 반영하여 GAP 인증 수삼이 어떤 소비자를 대상으로 어떠한 방향의 마케팅전략을 수행해야하는지에 대한 방향성 제시를 위해 수삼 선택속성별 부분가치를 산출하였으며 GAP 인증 수삼의 시장예상점유율 시뮬레이션, 시장세분화(segmentation), 표적시장선정(targeting), 표적시장 소비자 특성 등에 대한 일련의 연구를 수행하였다. 수삼 선택의 주요 속성인 안전성, 크기, 가격에 대한 부분가치효용을 분