• 대한안전경영과학회지
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• 제21권2호
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• pp.1-8
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• 2019

Most of gas turbine combined cycle power plants are located in urban areas to provide peak load and district heating. However, NOx(nitrogen oxides) of exhaust gas emission from the power plants cause additional fine dust and thus it has negative impact on the urban environment. Although DLN(dry low NOx) and multi-stage combustors have been widely applied to solve this problem, they have another critical problem of damages to combustors and turbine components due to combustion dynamic pressure. In this study, the effect of different fuel ratio on NOx emission and pressure fluctuation was investigated regarding two variable conditions; combustor stages and power output on M501J gas turbine.

• 대한한방소아과학회지
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• 제23권1호
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• pp.37-72
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• 2009

Objectives The purpose of this study is to investigate the suppressive effects of Atopy cream-combined with Jawoongo ointment (A-J), on the development of atopic dermatitis-like skinlesions in NC/Nga mouse. Methods We evaluated clinical skin score, hematology and Serum total IgE and IgG1 of NC/Nga atopic dermatitis mouse, analyzed the cytokine level, total cell number, Immunohistochemical staining and Histological features of axillary lymph node(ALN), draining lymph node(DLN), peripheral blood mononuclear cells(PBMCs) and dorsal skin tissue in NC/Nga mouse. Results A-J decreased the clinical skin score, total cell number of WBC, platelet, neutrophils, eosinophils in blood, Serum total IgE & IgG1, IL-5, IL-13. Also, total cell number of ALN and dorsal skin tissue, Absolute cell number of $CD3e^+$&$CD19^+$, $CD4^+$&$CD8^+$, $CD3^+/CCR3^+$, $CCR3^+$, $CD3^+/CD69^+$, $CD3^+/CXCR5^+$ in ALN, PBMCs, Absolute cell number of $CCR3^+$, $CD3^+/CD69^+$, $CD11b^+/Gr-1^+$ in dorsalskin tissue, Eotaxin2 mRNA, CCR3 mRNA in dorsal skin tissue and gene expression of IL-5 mRNA, IL-13 mRNA in ALN decreased significantly. Furthermore, thickness of epidermis, infiltrated inflammatory immune cell and mast cell in dermis, histologic infiltration of mast cell, the size of inflammatory lymphocytes cells and plasma cells in ALN and histologic infiltration of CD4+ & CCR3+ in ALN and dorsal skin tissue decreased significantly. However, total cell number of DLN, absolute cell number of $CD3e^+$&$CD19^+$, $CD4^+$&$CD8^+$, $B220^+/CD23^+$, $CD3^+/CD69^+$ increased significantly. Conclusions A-J was the successful treatment of atopic dermatitis in a NC/Nga mouse model.

• 동의생리병리학회지
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• 제23권5호
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• pp.1106-1115
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• 2009

Mori Ramulus has multiple applications in Korean traditional medicine prescription because it has antioxidant and anti-inflammatory effects by reducing macrophage activities. Yet, no studies on the anti-arthritic activity of EMR (extract of Mori Ramulus) have been reported in vitro and in vivo. Rheumatoid arthritis (RA) is a systemic autoimmune disease with chronic inflammation characterized by hyperplasia of synovial cells in affected joints, which ultimately leads to the destruction of cartilage and bone. Because collagen-induced arthritis (CIA) is similar to RA in pathological symptoms and immune reactions, there have been several reports concerning RA using CIA mouse model. Here, we investigated the effects of Mori Ramulus on RA using CIA mice. The importance of CD4+ Th1 cells in RA progress was previously indicated and studies further showed that Th17 cells play a prime role in severity of disease. Accordingly, the present study was focused on CIA associated with CD4+ Th1 cells and Th1 7 cells. DBA/1OlaHsd mice were immunized with bovine type II collagen (CII). After a second collagen immunization, mice were treated with EMR once a day for 4 weeks. The severity of arthritis within the paw joints was evaluated by histological assessment of cartilage destruction and pannus formation. Immune cells in peripheral blood mononuclear cells (PBMC), draining lymph node (DLN) and paw joints, cytokine production and gene expression were assessed from CIA mouse using ELISA, FACS and real-time PCR analysis. Administration of EMR significantly suppressed the progression of CIA and inhibited the production of TNF-$\alpha$, IL-6 and IL-17 in the serum. The erosion of cartilage was dramatically reduced in mouse knees after treatment with EMR. In conclusion, our results demonstrate that EMR significantly suppressed the progression of CIA and that this action was mediated by the decreased production of TNF-$\alpha$, IL-6, IL-17 and collagen II-specific antibody in the serum. EMR suppressed Th17 cells and reduced level of IL-6 via B cell suppression, and thus, the levels of autoantibodies produced from B cells were decreased. Furthermore, EMR suppressed NKT cells which directly stimulate B cells and develop imbalance of Th1/Th2 cell. Oral administration of EMR (100 mg/kg or 200 mg/kg) significantly suppressed the progression of CIA, which is comparable to that of methotrexate (MTX, 0.3 mg/kg) used as a positive control. We are currently studying the mechanism underlying the therapeutic role for EMR in CIA mice.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.279-282
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• 2002

Recently, gas turbines for power generation adopt multistage DLN(Dry Low NOx) type combustion, where diffusion combustion is applied at low load and, with increase in load, the combustion mode is changed to lean premixed combustion to reduce NOx emissive concentration. However, during the mode changeover from diffusion to premixed flame, unfavorable phenomena, such as flashback, high amplitude combustion oscillations, or thermal damage of combustor parts could frequently occur. In the present study, to apply for the analysis of such unfavorable phenomena, three-dimensional CFD investigations are carried out to compare the detailed flow characteristics and temperature distribution inside the gas turbine combustor before and after combustion mode changeover. The fuel considered here is pure methane gas. A standard $k-{\varepsilon}$ turbulence model with wall function and a P-N type radiation heat transfer model, have been utilized. To analyze the complex geometric effects of combustor parts on combustion characteristics, fuel nozzles, a swirl vane f3r fuel-air mixing, and cooling air holes on the combustor liner wall, are included in this simulation.

• 한국연소학회지
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• 제9권1호
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• pp.11-17
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• 2004

The purposes of this study are to analyze nitrogen oxides(NOx) formation mechanism and to reduce abnormal NOx emissions in gas turbines. Industrial gas turbines emissions have potential to negative affect to the atmosphere in many different ways such as photochemical smog, acid rain and global warming. In conventional gas turbine combustors, one of the main pollutants such as nitrogen oxide(NOx) species, are principally formed from combustion process of fuel with oxygen in the primary combustion zone, and their emission levels are highly depend on peak temperatures in the combustor. In order to examine the characteristics and the effect of NOx formation, we used gas turbine of which commercial operating in Korea. From the examination, it has been found that NOx emissions are relatively high at low load(output) and during combustion mode change. Also, the effect of Air/Fuel ratio was considered. As the Air/Fuel ratio was increased in Lean-Lean mode, the NOx emission was decreased. The results of this study indicated that NOx emission levels are highly depend on peak temperature and pressure of combustion process in the combustor.

• 정보보호학회논문지
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• 제27권5호
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• pp.1201-1216
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• 2017

최근 한국을 비롯한 전 세계적으로 많은 국가들이 분산 원장 기술(예: 블록체인)을 활용한 온라인 투표를 적극적으로 도입하여 이용하고 있으나, 현재 널리 보급된 정보통신 인프라 기반의 분산 원장 기술을 활용한 온라인 투표 시스템에 대한 잠재적인 보안 위협 분석이 미흡한 실정이다. 본 논문에서는 분산 원장 기술을 활용한 온라인 투표 시스템에 대한 모델을 제시하고 온라인 투표 과정에서 발생할 수 있는 보안 위협을 정보보호 측면에서 분석함으로서 그에 따른 대응 방안을 제시하고자 한다.

• 에너지공학
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• 제13권2호
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• pp.144-151
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• 2004

희박 예혼합 연소방식을 채용한 150MW급 대형 저 NOx 가스터빈 연소기에서 발생하는 급격한 연소진동 발생을 저감하였다. 희박 예혼합 연소기에서는 연소튜닝이 적절히 이루어지지 많은 경우에 연소불안정에 기인한 높은 연소진동의 발생과 함께 NOx 배출량이 높아질 가능성이 있다. 대상 가스터빈의 연소 모드 전환 중에 발생하는 연소진동의 주파수와 크기는 각각 80Hz및 4-9psi로 나타났으며, 대기온도가 낮아짐에 따라 연소진동의 크기가 증가하는 경향을 보였다. 연소진동에 영향을 미치는 인자로서 버너노즐로 공급되는 연료유량을 균등화하기 위한 연소튜닝과 연소모드 전환시 연료라인에 연료를 미리 공급(prefilling)하는 것이 화염안정에 매우 큰 효과가 있었다. 그 결과 연소모드 전환 중에 발생하는 연소진동을 2.5psi까지 저감할 수 있었으며, 150 MW기저부하 운전 중에 NOx 발생량을 35-43ppm(15% $O_2$)으로 유지할 수 있었다.

• 대한한의학방제학회지
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• 제21권1호
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• pp.161-176
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• 2013

Objectives : To clarify the anti-arthritic activity of Ostericum koreanum Maxim. (OS) plus Aralia continentalis Kitagawa (AC) in vivo. Methods : All mice were immunized with bovine type II collagen. After a second collagen immunization, mice were treated with OS plus AC once a day for 7 weeks. Oral administration of OS plus AC (200 or 50 mg/kg) significantly suppressed the progression of CIA, which extend is comparable to that of methotrexate (MTX, 0.3 mg/kg), a positive control. The severity of arthritis within the knee joints was evaluated by histological assessment of cartilage destruction and pannus formation. Results : Administration of OS plus AC significantly suppressed the progression of CIA and inhibited the production of TNF-${\alpha}$ and IL-6 in serum. The erosion of cartilage was dramatically reduced in mouse knees after treatment with OS plus AC. In conclusion, our results demonstrates that OS plus AC significantly suppressed the progression of CIA and that this action was characterized by the decreased production of IL-6, IFN-${\gamma}$ and collagen II specific antibody in serum, CD3+CD69+ T cells, MHC class II+/CD11c+ (in DLN), CD11b+Gr-1+ cells (in PBMC), CD11b +Gr-1+ cells, B220+/CD23+ (in paw joint). Conclusions : The the levels of IFN-${\gamma}$ in the culture supernatant of splenocytes stimulated with CD3/CD28 or collagen were dramatically decreased, while those of IL-4 was increased. In the serum of OS and AC-treated mice, the levels of IgM RA factor were decreased.

• 대한본초학회지
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• 제30권1호
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• pp.95-101
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• 2015

Objectives : The aim of this study was to confirm whether or not coral has a preventive effect on development of atopic dermatitis induced by house mite(dermatophagoides pteronyssinus) in NC/Nga mice. Methods : This study was undertaken by using a reliable Atopic dermatitis mouse model demonstrating similar immune response. Lobophytum crassum was administered orally to NC/Nga mouse for 3 weeks. In order to verify the effectiveness of Lobophytum crassum in atopic dermatitis treatment, its role in immune factors were observed in NC/Nga mice. Results : ALT, AST, BUN and creatine levels were all within in the normal ranges in MC-1 200 and 400 (mg/kg) treated groups, indicating no induced toxicity. MC-1 200 and 400 (mg/kg) groups decreased of atopic dermatitis skin manifestation in NC/Nga mouse of MC-1 200 and 400 (mg/kg) groups compared to that of the control group and decreased the ratio of WBC and lymphocyte in blood. Also, MC-1 200 and 400 (mg/kg) groups significant decreased the ratio of CD4+, CD8+, CD11b+/Gr1+, B220/CD23 and CD4/CD25 immune cell ratio in ALN. Finally MC-1 200 and 400 (mg/kg) groups significantly increased the ratio of CD4+, CD8+, B220/CD23 and CD4/CD25 immune cells in DLN. Conclusions : Theses results suggested that Lobophytum crassum has suppressive effects on aberrant and overactive immunological activities in dermatophagoides pteronyssinus-induced dermatitis mice of NC/Nga.

• 동의생리병리학회지
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• 제21권2호
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• pp.392-398
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• 2007

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by inflammatory cell infiltration in the skin. This study was performed to assess the therapeutic effects of YHYBT on the DNCB-induced dermatitis in NC/Nga mice, characterized by the onset of AD along with an increase the number of Th2 cells and dysregulation of inflammaroty mediators including cytokines and chemokines. YHYBT administration significantly reduced clinical dermatitis severity including pruritus, edema, eczematous and erythema. Histological findings indicated that the thickening of epidermis/dermis and dermal infiltration of inflammatory cells including mast cells were dramatically reduced. The suppression of dermatitis by YHYBT was accompanied by a decrease in the total number of immune cells in drained lymph node (DLN) and skin. Especially CD3+, CD4+ and CD3+CD69+ T cells in PBMC and DNL were greatly reduced. The level of IL-4 in CD3/CD28 activated splenocyte was downregulated, whereas that of IFN-'처리불가‘ was increased. Furthermore, the expression of eotaxin2 and CCR3 in skin were significanlty decreased. These data suggest that YHTBT may be effective therapeutic agents for the treatment of AD.