• 한국유체기계학회 논문집
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• 제11권1호
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• pp.52-60
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• 2008

Staggered dimples printed on opposite walls of an internal cooling channel are formulated numerically and optimized to enhance heat transfer performance. Nusselt number and friction factor based objectives are considered and a weighted average surrogate model is used to approximate the data generated by numerical simulation. The dimpled channel shape is defined by three geometric design variables, and the design point within design space are selected using Latin hypercube sampling. A weighted-sum method for multi-objective optimization is applied to integrate multiple objectives into a single objective. By the optimization, the objective function value is improved largely and heat transfer rate is increase much higher than pressure loss increase due to shape deformation. Channel with vertically non-symmetric optimum dimples is tested and found that the best appears if dimples on opposite wall are displaced by one quarter of dimple spacing.

• IMMUNE NETWORK
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• 제6권1호
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• pp.13-19
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• 2006

Background: Granulocyte colony stimulating factor (G-CSF) is known as a cytokine central to the hematopoiesis of blood cells and to modulate their cellular functions. Besides granulocytes and their precursors, monocytes/macrophages and endothelial cells are direct target cells of G-CSF action. G-CSF influences immune cells in an anti inflammatory way. Methods: To evaluate whether G-CSF has a potential for preventing or ameliorating diseases characterized by mucosal inflammation, we used a mouse model with trinitrobenzene sulfonic acid (TNBS)-induced inflammatory colitis. To the mice model G-CSF was administrated daily by intraperitoneal injection. Macroscopic evaluation and immunohistochemical analysis of colonic tissues were performed. Results: Re combinant human G-CSF significantly inhibited LPS-induced TNF-${\alpha}$ mRNA expression in THP-1 cells. As for in vivo relevance, G-CSF dramatically reduced the weight loss of mice, colonic damage, and mucosal ulceration that characterize TNBS colitis. Moreover, G-CSF suppressed the expression of tumor necrosis factor-${\alpha}$, interleukin-$1{\beta}$, and intercellular adhesion molecule-1 in TNBS colitis. Conclusion: Current results demonstrate that G-CSF may be an effective agent for the treatment of diseases characterized by mucosal inflammation.

• 한국통신학회논문지
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• 제40권2호
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• pp.355-362
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• 2015

본 연구에서는 X-밴드 레이더에서 사용하는 9.385[GHz] 서큘레이터를 Y형 WR112 도파관속에 페라이트를 삽입하여 제작을 하였다. 페라이트 설계는 B/R(Below Resonance) 모드 방식을 사용하여, 페라이트 내부에서 전계 분포가 120도의 회전이 발생하는 조건과 페라이트의 내부의 직류 자계의 세기와 외부 자계의 세기를 계산하였다. 또한, 임피던스 정합을 포함하여 대역폭, 선택도, 삽입손실 등, 서큘레이터의 성능 향상을 위하여 두 개의 페라이트 사이에 같은 형태의 유전체를 삽입하였다. 최적의 페라이트 형태 및 유전체를 얻기 위하여 CST MWS를 이용하였다. 9.385[GHz]에서 시뮬레이션 결과는 정재파비 1.02, 분리도 -40dB, 삽입손실 0.2dB의 결과를 얻었고, 측정 결과는 정재파비 1.03, 분리도 -38dB, 삽입손실 1.2dB 이었다. 분리도, 정재파비는 시뮬레이션 결과와 잘 일치 하였지만, 삽입손실은 약 1dB 정도 크게 발생하였다.

• International Journal of Fluid Machinery and Systems
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• 제2권1호
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• pp.80-91
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• 2009

In this study, a prediction theory for specific noise that is the overall characteristic of the fan has been proposed. This theory is based on total pressure prediction and broadband noise prediction. The specific noises of two forward curved fans with different number of blades were predicted. The flow around the impeller having 120 blades (MF120) was more biased at a certain positions than the impeller with 40 blades (MF40). An effective domain of the energy conversion of MF40 has extended overall than MF120. The total pressure was affected by the slip factor and pressure loss caused by the vortex flow. The suppression of a major pressure drop by the vortex flow and expansion of the effective domain for energy conversion contributed to an increase in the total pressure of MF40 at the design point. The position of maximum relative velocity was different for each fan. The relative velocity of MF120 was less than that of MF40 due to the deviation angle. The specific noise of MF120 was 2.7 dB less than that of MF40 due to the difference in internal flow. It has been quantitatively estimated that the deceleration in the relative velocity contributed to the improvement in the overall performance.

• 대한치과보철학회지
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• 제47권2호
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• pp.136-147
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• 2009

연구목적: 골유착이라는 개념이 도입된 후, 임플란트의 등장은 치과계에 많은 변화를 일으키게 되었다. 임플란트를 이용한 상실치아의 수복은 안정된 시술방법으로 시행되어져 왔으며 그 적용 범위가 확대되었고 사용 빈도도 급격히 증가해왔다. 이에 따라 국산 임플란트의 사용 빈도도 높아지고 그 종류 또한 증가하였으나 장기간의 임상적, 객관적인 자료를 가진 국산 임플란트의 수는 많지 않은 상태이다. 본 연구는 연세대학교 치과대학 병원에 내원한 환자 중 SLA 표면 처리 및 미세나사선을 가진 내측 연결형의 $Implantium^{(R)}$ 임플란트를 이용하여 치료받은 38명의 환자에게 식립된 106개의 임플란트를 대상으로 6개월에서 30개월까지의 임상적, 방사선학적 결과를 후향적으로 분석하였다. 연구재료 및 방법: 진료기록부를 통해 성별, 연령, 식립 위치, 식립 부위의 골 상태, 식립된 임플란트의 직경 및 길이, 2차수술및골이식여부, 대합치의 유형, 임상적 합병증의 유형 및 빈도 등을 조사하여 그에 따른 분포 및 생존율의 차이와 함께 이들 항목이 변연골 흡수량에 미치는 영향을 조사하였다. 방사선 사진분석으로 임플란트 식립시, 보철물 장착 후 첫 6개월 내지 1년간, 그 이후 연간 변연골 흡수량을 측정하여 분석하였다. 결과: 1. 총 38명에게 식립된 106개의 임플란트 중 1개가 실패하여 누적 생존율은 99.1%로 나타났다. 2. 보철물 장착 후 최소 6개월 이상 정기검진이 가능했던 96개의 임플란트에서 상악에서의 생존율이 97.0%, 하악에서의 생존율은 100%였고, 구치부에서의 생존율은 98.9%였으며 전치부에서의 생존율은 100%였다. 3. 보철물 장착 후 첫 1년간의 변연골 흡수량은 평균 0.17 mm 이었으며, 1년 이후의 연간 변연골 흡수량은 평균 0.04 mm로 통계학적으로 유의차 있게 적은 골소실량을 나타내었다(P<.05). 4. 보철물 장착 후 첫 1년간 연령에 따른 변연골 흡수량의 차이는 보이지 않았으나(P>.05), 1년 이후의 정기 검진 기간에서 50세 이상의 환자에서 50세 미만의 환자보다 큰 연간 변연골 흡수량을 보였다(P<.05). 5. 성별 간, 악궁 간, 전치부와 구치부위 간, 2차 수술 및 골 이식 여부, 보철물의 유형, 대합치의 유형에 따른 변연골 흡수량의 차이는 보이지 않았다(P>.05). 결론: 이상의 결과를 토대로 변연골 흡수량에 영향을 주는 요소로 연령을 들 수 있었으며 성별, 악궁 간, 악궁 내 위치, 2차 수술 및 골 이식 여부, 보철물의 유형, 대합치의 유형에 따른 변연골 흡수량의 차이는 없었다. 본 연구에서 최대 30개월까지의 기간 동안 SLA 표면 처리 및 미세나사선을 가진 내측 연결형의 국산 임플란트의 임상적인 성공률은 만족스러운 결과를 보였으며 변연골 흡수량도 임플란트 성공 기준에 부합하였다.

• Wind and Structures
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• 제16권1호
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• pp.1-23
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• 2013

The wind-induced transient response of internal pressure following the creation of a sudden dominant opening during the occurrence of high external pressure, in low-rise residential and industrial buildings was numerically investigated. The values of the ill-defined parameters namely the flow contraction coefficient, loss coefficient and the effective slug length were calibrated by matching the analytical response with the computational fluid dynamics predictions. The effect of a sudden i.e., "instantaneously created" windward opening in the Texas Technical University (TTU) test building envelope was studied for two different envelope flexibility-leakage combinations namely: (1) a quasi-statically flexible and non-porous envelope and (2) a quasi-statically flexible and porous envelope. The responses forced by creating the openings at different time leads/lags with respect to the occurrence of the peak external pressure showed that for cases where the openings are created in close temporal proximity to the peak pressure, the transient overshoot values of internal pressure could be higher than the peak values of internal pressure in the pre-sequent or subsequent resonant response. In addition, the influence of time taken for opening creation on the level of overshoot was also investigated for the TTU building for the two different envelope characteristics. Non-dimensional overshoot factors are presented for a variety of cavity volume-opening area combinations for (1) buildings with rigid/quasi-statically flexible non-porous envelope, and (2) buildings with rigid/quasi-statically flexible and porous envelope (representing most low rise residential and industrial buildings). While the factors appear slightly on the high side due to conservative assumptions made in the analysis, a careful consideration regarding the implication of the timing and magnitude of such overshoots during strong gusts, in relation to the steady state internal pressure response in cyclonic regions, is warranted.

• 대한한방내과학회지
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• 제34권1호
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• pp.59-70
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• 2013

Objectives : This study was designed to test the effect of a warm environment and Bujaijung-tang on immune and lipid metabolism in rats. Methods : The extract from Bujaijung-tang was made by the pharmacy department of Kyung-Hee oriental medical hospital. The animals were divided into four groups, by room or warm environment and Bujaijung-tang administration. Each group had 8 Sprague-Dawley Rats. We measured body temperature twice a week, body weight three times a week. After 3 weeks of experiment, serum lipid level, WBC, differential count, lymphocyte proliferation and immune cytokine concentration were measured. Results : 1. warm environment induced weight loss in rats. 2. warm environment induced a decrease of total cholesterol and low-density lipoprotein (LDL) cholesterol gain. 3. warm environment and Bujaijung-tang induced an increase of tumor necrosis factor (TNF)-${\alpha}$ concentration. Conclusions : The warm environment had a hyperlipidemia modulating effect. The warm environment and Bujaijung-tang had an immune modulating effect.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2465-2470
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• 2008

A new surface shape of an internal cooling passage which largely reduces the pressure drop and enhances the surface heat transfer is proposed in the present study. The surface shape of the cooling passage is consisted of the concave dimple and the riblet inside the dimple which is protruded along the stream-wise direction. Direct Numerical Simulation (DNS) for the fully developed turbulent flow and thermal fields in the cooling passage is conducted. The Numerical simulations for the 5 different surface shapes are conducted at the Reynolds number of 2800 based on the mean bulk velocity and channel height and Prandtl number of 0.71. The driving pressure gradient is adjusted to keep a constant mass flow rate in the x direction. The thermo-aerodynamic performance for the 5 different cases used in the present study was assessed in terms of the drag, Nusselt number, Fanning friction factor, Volume and Area goodness factor in the cooling passage. The value of maximum ratio of drag reduction is -22.86 [%], and the value of maximum ratio of Nusselt number augmentation is 7.05 [%] when the riblet angle is $60^{\circ}$ (Case5). The remarkable point is that the ratio of Nusselt number augmentation has the positive value for the surface shapes which have over $45^{\circ}$ of the riblet angle. The maximum Volume and Area goodness factor are obtained when the riblet angle is $60^{\circ}$ (Case5).

• 대한간호학회지
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• 제47권5호
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• pp.589-599
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• 2017

Purpose: The purpose of this study was to develop a scale to assess the transition shock experienced by newly graduated nurses, and test the validity and reliability of the scale. Methods: The initial items were identified through a review of literature and in-depth interviews with nine newly graduated nurses. Content validation of the items was evaluated by five nurse professors and three nurses. Participants were 269 newly graduated nurses who worked at six acute care hospitals in Busan, Ulsan, and Yangsan, South Korea. Data were analyzed using item analysis, exploratory and confirmatory factor analysis, criterion related validity, and internal consistency. Results: The final scale consisted of 18 items and six factors (conflict between theory and practice, overwhelming workload, loss of social support, shrinking relationship with co-workers, confusion in professional nursing values, and incongruity in work and personal life), which explained 71.3% of the total variance. The six subscale model was validated by confirmatory factor analysis. Cronbach's alpha for the total items was. 89. Convergent validity was evaluated by analyzing total correlation with burnout (r=.71, p<.001) and turnover intention (t=5.84, p<.001). Conclusion: This scale can be used in the development of nursing interventions to reduce the transition shock experienced by newly graduated nurses.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 방전 플라즈마 유기절연재료 초전도 자성체연구회
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• pp.69-72
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• 2004

In recent, there have been several developments in lamp technology that promise savings in electrical power consumption and improved quality of the lighting space. Above all, the advantage of ring-shaped electrodeless fluorescent lamp is the removal of internal electrodes and heating filaments that are a light-limiting factor of conventional fluorescent lamps. The ring-shaped electrodeless lamp is intended as a high efficacy replacement for the incandescent reflector lamp in many applications. Therefore, the life time of ring-shaped electrodeless fluorescent lamps is substantially higher than that of conventional fluorescent lamps and last up to 60,000 hours. In this paper, we present measurement results of electrical characteristics of a ring-shaped electrodeless fluorescent lamp as a function of frequency and number of coil turns using a highly permeable Mn-Zn ferrite. It is found that the impedance are increased while the quality factor decreases as frequency increases.