• 대한화장품학회지
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• 제50권2호
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• pp.103-110
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• 2024

지질나노입자(lipid nanoparticles, LNPs)란, 세포 불투과성인 치료용 핵산, 단백질 및 펩타이드와 같은 생물학적 활성 화합물을 미세한 환경 변화에 의한 분해로부터 보호해 안정적이면서 효과적인 약물전달시스템이다. 본 연구에서는 지용성 비타민 C 유도체인 테트라헥실데실아스코르베이트(tetrahexyldecyl ascorbate, THDC)의 생체 내 반감기를 효과적으로 연장시키기 위해 산화방지제인 갈릭산(gallic acid, GA)을 함유하는 지질나노입자를 개발하였다. 마이크로플루이딕스칩(microfludics chip)을 통해 상온 및 상압 조건 하에서 작고 균일한 크기로 제작하였다. 기존 마이크로플루다이저(microfluidizer)를 통해 고압 및 고온 조건 하에 제작된 리포좀과 비교하였을 때, 마이크로플루이딕스칩(microfludics chip)을 통해 제작된 LNPs인 경우, 분산 및 온도에 따른 안정성이 우수하였으며, 지용성 비타민 C 유도체의 산화 안정성을 향상시켰을 뿐 아니라 피부 흡수율도 개선된 것을 확인하였다. 향후 연구에서는 이러한 결과를 더욱 입증하기 위해 피부 개선 효과를 연구하기 위한 생체 외 및 생체 내 평가에 중점을 둘 것이다.

• 한국정밀공학회지
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• 제26권8호
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• pp.119-125
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• 2009

Fabrication of a three-dimensional (3D) metallic mold for multi-production of a microstructure was studied to settle the problem of long processing time in 3D microfabrication. To date, complicated 3D microstructures including 3D photonic crystals, 3D microlens array, 3D filter for microfludics, and something else were created successfully using the two-photon polymerization (TPP) which was considered as paving the way to fabricate a real 3D shape in nano/microscale. However, for those fabrications, much processing time and efforts were inevitably required. To solve this issue, a simple and effective way was proposed in this paper; 3D master patterns were prepared using TPP, and then counter-shaped Ni molds were fabricated by electroforming process. By using these molds, 3D microstructures can be reproduced with short-processing time and low-effort comparing to the conventional approach, TPP We report some parameters to fabricate a metallic mold precisely.

• 대한기계학회논문집B
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• 제28권9호
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• pp.1015-1021
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• 2004

Micro-resolution Particle Image Velocimetry(Micro-PIV) was used to measure the flow in a micro-branch(Micro-Bypass). In this paper, effects of particle lump at the tip of a Micro-branch and difficulties of Micro-PIV measurements for microfluidics with branch passage were described. Micro-bypass was composed of a straight channel(200(100)${\mu}$m width ${\times}$ 80${\mu}$m height) and two branches which has 100(50)${\mu}$m width ${\times}$ 80${\mu}$m height. One of branches was straight and the other was curved. Experiments were performed at three regions along streamwise direction(entrance, middle and exit of branch) and five planes along vertical direction (0, ${\pm}$10, ${\pm}$20 ${\mu}$m) for the range of Re=0.24, 1.2, 2.4. Numerical simulation was done to compare with the measurements and understand the effects of particle lump at the tip of branch. And another fluid(3% poly vinyl Alcohol aqueous solution) were adapted for this study, so there were no particle sticking. In this case, we could get velocity difference between straight and curved branches.

• 대한의용생체공학회:의공학회지
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• 제36권3호
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• pp.61-68
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• 2015

In this paper, we studied the effects of intersection angles of the flow-foucusing type droplet generation device inlet channel on droplet diameter using numerical simulation modeling. We modeled different intersection angles with a fixed continuous channel width, dispersed channels width, orifices width, and expansion channels width. Numerical simulations were performed using COMSOL Multiphysics$^{(R)}$ to solve the incompressible Navier-Stokes equations for a two-phase flow in various flow-focusing geometries. Modeling results showed that an increase of the intersection angle causes an increase in the modification of the dispersed flow rate ($v^{\prime}{_d}$), and the increase of the modification of the continuous flow rate ($v^{\prime}{_c}$) obstructs the dispersed phase fluid flow, thereby reducing the droplet diameter. However, the droplet diameter did not decrease, even when the intersection angle increased. The droplet diameter decreased when the intersection angle was less than $90^{\circ}$, increased at an intersection angle of $90^{\circ}$, and decreased when the intersection angle was more than $90^{\circ}$. Furthermore, when the intermediate energy deceased, there was a decrease in the droplet diameter when the intersection angle increased. Therefore, variations in the droplet diameter can be used to change the intersection angle and fluid flow rate.

• 한국지반신소재학회논문집
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• 제14권1호
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• pp.23-32
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• 2015

본 연구에서는 지반 내 오염원제거와 저투수성 지반의 개량이 동시에 이루어 질 수 있는 연직배수시스템의 최적화 기술을 마련하기 위하여, 중금속 오염물질을 대상으로 미세유체 흐름실험을 수행하였으며, 그 결과를 바탕으로 pH조건에 따른 흐름특성을 분석하였다. 중금속 오염물에 대한 미세유체 흐름실험 결과, 소수성 성질이 반영되는 위치가 오염물의 흐름속도에 큰 영향을 미치는 것으로 분석되었으며, pH 조건이 흐름속도 변화에 영향인자로 작용하였다. 또한 복합 중금속 오염물인 경우에 pH가 염기성일수록 납의 흐름속도가 다소 증가하는 경향으로 나타났는데, 이는 납 오염물이 구리에 비하여 소수성 표면특성을 감소시킬 수 있음을 의미하는 결과라 할 수 있다.