• 대한의생명과학회지
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• 제13권3호
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• pp.175-182
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• 2007

In vitro ciprofloxacin (CFX)-release study and bioassay using microorganisms were performed to estimate the retention of the antimicrobial activity of the CFX-incorporated central venous catheters (CFX-CVCs). The release experiments were carried out under the optional CFX-release conditions to mimic the in vivo environment. The release of CFX experienced an initial burst followed by a slow and steady matrix-diffusion controlled release. The 1.0CP (polyurethane catheter containing 1.0% (w/w) of CFX) under dynamic condition showed a near zero-order CFX release profile, which is beneficial for the long-tenn antimicrobial activity. The modified Kirby-Bauer method was performed employing S. aureus and E. coli to evaluate the retention of antimicrobial activity of the catheters retrieved from the release experiments. The 1.0CP showed the long-term antimicrobial activity (${\geq}\;21$ days) against both S. aureus and E. coli. These results indicate that 1.0CP is useful as a long-tenn indwelling CVC.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.715-716
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• 2012

• 한국가시화정보학회지
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• 제9권4호
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• pp.22-27
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• 2011

In this study, we present methods of coupling a commercial code, ANSYS CFX, and the user Fortran codes for solving an unsteady electro-osmotic flow around a pair of electrodes, receiving DC, attached to the top and the bottom walls of a two-dimensional cavity. We developed a module of Fortran programs for solving the ion-transport equations as well as the Poisson equations for the potential to be used in coupling with the CFX. We present how the developed codes are applied to solving the transient DC electro-osmotic flow problem within a simple cavity. We also address various problems encountered during the development process and explain why such problems are raised.

• 대한의생명과학회지
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• 제15권1호
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• pp.73-80
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• 2009

Bloodstream infections (BSI) are caused by planktonic microorganisms, sometimes leading to serious infections such as bacteremia and sepsis. BSI occurs more frequently to the patients wearing the central venous catheter (CVC). The ciprofloxacin-incorporated CVC (CFX-CVC) has been reported previously to possess antimicrobial activity. In this study, the antibacterial activity of CFX-CVC and its mechanism against planktonic BSI cells were explored by using the shake flask test and by examining the release rate of 260 nm-absorbing substances from the bacterial cells indicative of the membrane damage of the bacterial cells. CFX-CVC reduced more than 99.9% of the viable planktonic BSI cells demonstrating its potent antibacterial activity. It provoked bacteriolysis causing leakage of a large amount of 260 nm-absorbing materials from the planktonic bacterial cells like S. aureus and E. coli. These results provide evidence that the antibacterial activity of CFX-CVC came from the inhibition of the stability of the planktonic bacterial cells.

• 대한의생명과학회지
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• 제10권3호
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• pp.245-251
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• 2004

Microbial infection provokes one of the most serious complications to the patients with indwelling catheters. Ciprofloxacin (CFX) was added into the catheter materials (polyurethane or silicone) during the manufacturing process to avoid the microbial infection. Efficacy of the catheters containing CFX was investigated by using the in vitro zone of growth inhibition test method. The catheters made of polyurethane or silicone exhibited a strong antimicrobial activity against the major catheter-related microorganisms (S. aureus, S. epidermidis, P. aeruginosa and E. coli), when CFX was incorporated into the catheters. Fetal bovine serum (FBS) did not affected antimicrobial activities of the polyurethane catheters with CFX loading of 0.5 and 1.0％ (W/W) against S. aureus and S. epidermidis. However, the polyurethane catheters with 1.0％ (W/W) of CFX loading showed a significantly (P<0.05) reduced antimicrobial activity against E. coli when the catheters were exposed to FBS. Silicone catheters with 1.0 and 1.5％ (W/W) of CFX loading demonstrated effective antimicrobial activity against S. epidermidis for at least 2 weeks. These results suggest that the use of catheters containing ciprofloxacin could be effective in preventing catheter-related infections.

• 대한기계학회논문집B
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• 제39권10호
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• pp.831-842
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• 2015

본 논문에서는 사류펌프의 성능을 향상시키는 최적화 방법을 개발하였다. 본 연구에서 개발한 최적화 방법은 유동해석코드인 CFX 와 최적화 소프트웨어인 HEEDS 를 연계하는 프로세스로 이루어진다. CFX 는 유체기계해석 분야에서는 잘 알려진 소프트웨어로 해석결과의 신뢰성은 이미 검증되었으나, 새롭게 소개되고 있는 HEEDS 는 주로 구조해석 분야에서 최적화를 수행한 사례가 보고되어 있다. 이에 본 논문을 통해 유체기계에 적용하여 최적화 결과를 검토하였다. HEEDS 에는 SHERPA 라는 최적화 기법이 탑재되어 있으며, 다수의 설계변수를 설정할 수 있어 변수간의 교호작용 등을 효율적으로 검토할 수 있다. 본 논문에서는 DOE 방법으로 최적화가 이루어진 사류펌프 임펠러에 대해 개발된 방법을 적용하여 최적화 결과의 타당성과 안정성을 검토하였으며, 같은 방법을 디퓨저에 적용하여 최적화 형상을 검토하였다. 본 논문에서 개발된 최적화 방법을 이용하여 사류펌프 최적화를 수행한 결과, DOE 방법을 이용한 설계보다 개선된 결과를 적절한 시간 내에 얻을 수 있음을 확인하였다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 추계학술발표회요약집
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• pp.144.2-144
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• 2001

• 한국유체기계학회 논문집
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• 제15권5호
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• pp.37-41
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• 2012

High-efficiency and low-noise axial flow fan is developed by combining the FanDAS, a computerized axial fan design/performance analysis system, and CFD software(CFX). Based on fan design requirements, FanDAS conducts 3-D blade geometry design, quasi-3D flow/ performance analyses and noise evaluation by using through-flow analysis method and noise models for discrete frequency and broadband noise sources. Through the parametric studies of fan design variables using FandDAS, preliminary and baseline design is achieved for high efficiency and low noise fan, and then can be coupled with a CFD technique such as the CFX code for constructing final and optimized fan design. The FanDAS-CFX coupled system and its design procedure are applied to actual fan development practice. The FanDAS provides an optimized 3-D fan blade geometry, and its predictions on the performance and the noise level of designed fan are well agreed with actual test results.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2012년도 학술발표회
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• pp.582-586
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• 2012

본 연구에서는 ANSYS CFX 모형을 이용하여 임의형상 파샬플륨 내에서의 유동모의 및 해석을 수행하였다. 상류경계조건으로 파샬플륨 상류 2m 지점을 기점으로 하여 상류수위를 0.2, 0.25 그리고 0.3m로 변화시켰으며, 하류경계조건은 상류수위의 0.5, 0.8 그리고 0.9로 변화시키면서 모의를 수행하였다. 모의된 결과는 수리모형실험으로부터 측정된 결과와 FLOW-3D 모형에 의한 모의결과와의 비교를 통해 검증하였다. 또한, 격자 시스템의 조밀도 정도(T-1, T-2, T-3, T-4)에 따른 유동변화 양상을 분석하였다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2004년도 추계학술발표회 발표논문집
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• pp.283-284
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• 2004