• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제24권2호
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• pp.37-44
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• 2018

Purpose: This study investigates the influences of coughing direction and healthcare worker's location on the transport characteristics of coughed particles in airborne infection isolation room (AIIR), which is commonly called negative pressure isolation room, with a downward ventilation system. Methods: Computational Fluid Dynamics (CFD) was used to simulate the airflow and for tracing the behavior of particles. Results: The results show that the airflow pattern and coughing direction have a significant influence on the characteristics of particle dispersion and deposition. When healthcare workers are in the isolation room with the patient who is lying on the bed, it is recommended to be located far from the anteroom to reduce the exposures from infectious particles. And when the patient is lying, it is more effective in removing particles than when the patient is in Fowler's position. Although it is an isolation room that produces unidirectional flow, coughing particles can spread to the whole room and a large number of particles can be deposited onto patient, bed, side rails, healthcare worker, ceiling, floor, and sidewall. Implications: Following the patients' discharge or transfer, terminal cleaning of the vacated room, furniture, and all clinical equipment is essential. Also, it is necessary to establish detailed standard operating procedure (SOP) in order to reduce the risk of cross-contamination.

• BMB Reports
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• 제31권1호
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• pp.83-88
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• 1998

Recently a B cell surface molecule, CD40, has emerged as a receptor mediating a co-stimulatory signal for B cell proliferation and differentiation. To investigate the mechanism of synergy between interleukin-4 (IL-4) and CD40 ligation in B cell activation, we have examined the effect of CE40 cross-linking on the IL-4 receptor expression in human B cells using anti-CE40 antibody. We observed that IL-4 and anti-CD40 both induce IL-4 receptor gene expression with a rapid kinetics resulting in a noticeable accumulation of IL-4 receptor mRNA within 4 h. While IL-4 caused a dose-dependent induction of surface IL-4 receptor expression, the inclusion of anti-CD40 in the IL-4-treated culture, further up-regulated the IL-4-induced IL-4 receptor expression as analyzed by flow cytometry. Pretreatment of B cells with inhibitors of protein tyrosine kinase (PTK) resulted in a significant inhibition of both the IL-4- and anti-CD40-induced IL-4 receptor mRNA levels, while protein kinase C (PKC) inhibitors had no effects. These results suggest that IL-4 and CD40 ligation generate B cell signals, which via PTK-dependent pathways, lead to the synergistic induction of IL-4 receptor gene expression. The rapid induction of IL-4 receptor gene expression through the tyrosine kinase-mediated signal transduction by B cell activating stimuli, would provide cells capacity for an efficient response to IL-4 in the early phase of IL-4 action, and may in part constitute the molecular basis of the reported anti-CD40 co-stimulatory effect on the IL-4-induced response.

• 대한정형도수물리치료학회지
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• 제22권2호
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• pp.35-39
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• 2016

Background: The superficial lymphatic system is divided into areas called lymphatic territories which are separated by watersheds. When the lymphatic system fails to remove its load either due to surgery, radiotherapy or some congenital malformation of it then the fluid and the proteins and wastes contained within it accumulates in that territory. Anastomotic connections exist across the watersheds and while they can work unaided manual lymph drainage (MLD) can significantly help drainage across them into unaffected lymphatic territories. The purpose of the study is to examine the effectiveness of a manual technique in moving fluids and softening hardened tissues using a tape measure and Patient-Specific Functional Scale. Methods: We examined the movement of fluids from the affected limbs of lymphedema patients who underwent a standardized 30-min treatment using the Dr. Vodder method of MLD. We chose a typical cross section of patients with secondary leg or secondary arm lymphedema. The lymphedema patient was also measured after the conclusion of treatment and underwent a follow-up control measurement, within 8 weeks. Both evaluation tools indicated a movement of fluid to different and unblocked lymphatic territories as well as a softening of tissues in some of the affected limbs. Results: MLD is an effective means of fluid clearance when it accumulates as a consequence of a failure of the lymphatic system. It seems likely that MLD has a systemic effect on the lymphatic system and that it can improve flow from otherwise normal tissues. Conclusions: It is hypothesized that a series of treatments would result in even more significant improvements.

• 대한기계학회논문집B
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• 제39권10호
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• pp.773-778
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• 2015

가스터빈 냉각 장치인 블레이드 등과 같은 산업 설계를 개선하기 위해 사각 수축 및 확대채널에서 축방향의 거리에 따라 국부 난류 열전달과 압력강하에 대해 실험적으로 조사하였다. 수축 및 확대채널의 한 면에만 리브($10mm{\times}100mm{\times}5mm(t)$)를 연속적으로 배치하였고 충돌 각은 $90^{\circ}$로 피치(p)/높이(e)의 비는 10이 되도록 하였다. 수축채널의 수력직경비($D_{ho}/D_{hi}$)는 0.75, 확대채널의 수력직경비는 1.33 그리고 직선채널은 1.00이다. 열성능 비교를 위해 3가지 보편적인 제약 조건을 채택 하였다. 즉 동일 유량, 동일 펌프 동력 그리고 동일한 압력 강하이다. 3가지 조건모두 확대 채널에서 우수한 열 성능을 보였다.

• International Journal of Fluid Machinery and Systems
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• 제10권3호
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• pp.240-253
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• 2017

Latin hypercube sampling is widely used design-of-experiment technique to select design points for simulation which are then used to construct a surrogate model. The exploration/exploitation properties of surrogate models depend on the size and distribution of design points in the chosen design space. The present study aimed at evaluating the performance characteristics of various surrogate models depending on the Latin hypercube sampling (LHS) procedure (sample size and spatial distribution) for a diverse set of optimization problems. The analysis was carried out for two types of problems: (1) thermal-fluid design problems (optimizations of convergent-divergent micromixer coupled with pulsatile flow and boot-shaped ribs), and (2) analytical test functions (six-hump camel back, Branin-Hoo, Hartman 3, and Hartman 6 functions). The three surrogate models, namely, response surface approximation, Kriging, and radial basis neural networks were tested. The important findings are illustrated using Box-plots. The surrogate models were analyzed in terms of global exploration (accuracy over the domain space) and local exploitation (ease of finding the global optimum point). Radial basis neural networks showed the best overall performance in global exploration characteristics as well as tendency to find the approximate optimal solution for the majority of tested problems. To build a surrogate model, it is recommended to use an initial sample size equal to 15 times the number of design variables. The study will provide useful guidelines on the effect of initial sample size and distribution on surrogate construction and subsequent optimization using LHS sampling plan.

• 한국자동차공학회논문집
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• 제18권2호
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• pp.1-6
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• 2010

This study presents the practical design modification to improve the retracting performance of the pyro-typed high power pretensioner. 3 components of the pretensioner are redesigned and the usefulness of the design modification is verified by the experiment. During the pretensioning process, the gas blast generated from the gunpowder is transferred to the rack-pinion gear through the manifold. The rack-pinion gear is connected with the spool where the webbing is rolled up. According to the rotation of the pinion, the spool is turned and the webbing is winded. To help the gas blast flow well, the shape of the inner cross section of the manifold is changed. The spur gear design program is developed and used to find the best combination of the rack-pinion gear pair to increase the power transmission efficiency. The pinion guide is installed on the spool to prevent the vibration of the pinion. As a result of the experiment, the amount of the web retraction length is increased when every single design modification is applied. Therefore, the retracting performance of the pretensioner is considered to be improved if the presented design modifications are applied.

• 한국미생물·생명공학회지
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• 제9권3호
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• pp.165-171
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• 1981

E. coil ATCC 9637의 균체를 젤라틴과 DEAE-cellulose의 혼합 성형 후 글루트알데히드 가교법으로 제조론 고정화 penicillin amidase의 differential column reactor에서의 반응속도를 논의하였다. 이러한 반응조의 최적 조작조건은 효소충진량 1g, 기질농도30mM(0.1M 인산완충액, pH8.0), 유출속도 4 $m\ell$/min, 온도 4$0^{\circ}C$이었다. 이 최적조건에서 고정화효소의 일반적인 성질을 조사하였다. Km 상수는 4.8mM 이었고 specific activity 308 units/g 고정화 효소이 었다. 또한 고정화효소에서는 기질에 의한 효소반응 저해효과가 보이지 않았다. 이러한 differential column reactor에서는 column내에서의 pH 감소효과 및 외부 화산효과가 없어지기 때문에 이러한 외부적 영향을 받지 않는 고정화효소의 반응 속도론적 연구에 적합함을 알았다.

• 터널과지하공간
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• 제25권6호
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• pp.543-555
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• 2015

최근 대단면 갱도로 개발하고 있는 국내 석회석광산은 작업공간 환기를 위하여 과거 석탄광산에 광범위하게 사용되던 형태의 국부 선풍기를 주로 이용하고 있다. 대단면 갱도에서의 낮은 정압손실을 고려할 때 고풍압 선풍기는 과다 설비용량으로 인하여 비용측면에서 심각한 한계를 보이고 있다. 대단면 갱도에서의 최적 선풍기는 안전한 작업환경 유지를 위한 충분한 환기량을 공급할 수 있어야 할 뿐만 아니라 저운전비용도 보장하여야 한다. 본 연구는 대단면 갱도 내에서 높은 환기효율과 경제성을 가지는 저풍압 국부선풍기를 개발함이 목적이다. 이론적 연구와 아울러 2개소의 단면적이 다른 현장 실험 연구를 통하여 저풍압 선풍기의 환기효율을 분석하였다. 본 연구결과는 작업공간 공기질 및 작업환경 개선을 위한 국부선풍기의 경제성과 효율 제고에 적용 가능할 것으로 기대된다.

• Journal of Chest Surgery
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• 제22권6호
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• pp.1092-1100
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• 1989

Since May 1987 to April 1989, fifteen patients have been subjected to coronary artery bypass graft [CABG] including coronary thromboendarterectomy in 3 patients at Hanyang University Hospital. The correlation between the preoperative coronary angiography, electrocardiography, clinical status, operative finding and postoperative blood flow, complication and degree of clinical improvement were evaluated. 1. Ten patients [67 %] were male and five patients [33 %] were female, Ages ranged from 30 to 68 years. [average 52.2 years] 2. The angina by types of presentation was stable in 3 patients, unstable in 12 patients with resting, postinfarction and progressive angina as the criteria of unstability. 3. The number of involved vessels were single in 6 cases, double in 4 cases, triple in 5 cases including 1 case of left main coronary arterial disease. 4. The distribution of sites of distal anastomosis revealed predilection to left coronary arterial system [83 %], especially left anterior descending arterial system. 5. The author performed 4 cases of single bypass, 4 cases of double bypass, 5 cases of triple bypass and 2 cases of quadruple bypass. Of these 15 patients, 3 patients received coronary thromboendarterectomy, LAD in 2 patients and right coronary artery [RCA] in 1 patient. 6. The distal anastomosis were performed first with using saphenous vein grafts as conduits in all cases except 1 case using Gore-Tex conduit because of deficient in length and narrowed internal mammary artery and sequential bypass methods were employed in last 6 cases. 7. One operative death occurred and therefore, mortality rate was 6.7%. The perioperative myocardial infarction were occurred in 3 cases [20%] and its cause was supposed that they were triple vessel disease and therefore, aortic cross clamping times were relatively long. 8. All survivors were followed for 17.7 months on an average [range 5-28 months] and they have had symptomatic improvement except 1 case having mild degree of angina at 1.5 months after operation.

• 대한기계학회논문집
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• 제10권6호
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• pp.823-829
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• 1986

본 연구에서는 와동의 대류속도를 H.H. Brunn의 방법과 달리 측정하였으며, 또 이를 이용하여 와동의 중심들 사이의 간격을 구하고자 한다. 이를 위하여 먼저 포텐셜코어영역(potential core region)과 혼합층영역(mixing layer region)의 경계 및 천이영역(transition region)과 난류영역(turbulent region)경계를 구하여야 한다. 각 영역들의 대체적인 구분은 Fig.1과 같다.