• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 추계학술대회
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• pp.258-262
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• 1996

The physiological systems have nonlinear complex phenomena. Expecially, the flow of capillary blood vessel has a nonlinear dynamic system. Thus, this study analyzes nonlinear characteristics of the flow of capillary blood vessel in physiological systems using chaotic tools(phase space reconstruction, correlation dimension, largest lyapunov exponent). Experimental data have been acquired from examining 10 rabbits. The results of chaotic analysis showed a decreasing largest lyapunov exponent and correlation dimension according to increasement glocose index. And we also know the chaotic behavior.

• 대한기계학회논문집B
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• 제40권6호
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• pp.383-389
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• 2016

사각공동 및 채널이 형성된 마이크로구조 표면을 활용하여 수조비등 임계열유속에 대한 중력 및 모세관 압력의 영향에 대해 연구하였다. 마이크로 공동구조는 모세관 압력에 의한 액체유동을 억제하는 역할을 하였고, 마이크로 채널구조는 비등표면으로의 1차원적인 액체유동을 유발하는데 기여하였다. 이를 통해 임계열유속과 모세관 유동의 상관관계를 정량화할 수 있었다. 비등표면으로의 액체공급을 위한 원동력은 중력수두 및 모세관 압력에 의해 유발될 수 있다. 본 연구에서는 수조비등 실험 및 가시화 데이터의 분석을 통해 수조비등 표면에서의 핵비등을 유지할 수 있는 액체공급은 중력 수두 및 모세관 압력과 밀접한 상관관계를 가지고 있음을 확인할 수 있었다.

• 설비공학논문집
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• 제21권3호
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• pp.131-139
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• 2009

The simulation of refrigeration cycle is important since the experimental approach is costly and time-consuming. The present paper focuses on the simulation of a refrigeration cycle equipped with a capillary tube-suction line heat exchanger(SLHX), which is widely used in small vapor compression refrigeration systems. The present simulation is based on fundamental conservation equations of mass, momentum, and energy. These equations are solved through an iterative process. The non-adiabatic capillary tube model is based on homogeneous two-phase flow model. This model is used to understand the refrigerant flow behavior inside the non-adiabatic capillary tube. The simulation results show that both of the location and length of heat exchange section influence the coefficient of performance (COP).

• 대한기계학회논문집B
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• 제31권4호
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• pp.313-319
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• 2007

The effect of capillary cross-section geometry on evaporation is investigated in terms of the meniscus shape, evaporation rate and evaporation-induced flow for circular, square and rectangular cross-sectional capillaries. The shapes of water and ethanol menisci are not much different from each other in square and rectangular capillaries even though the surface tension of water is much larger than that of ethanol. On the other hand, the shapes of water and ethanol menisci are very different from each other in circular capillary. The averaged evaporation fluxes in circular and rectangular capillaries are measured by tracking the meniscus position. At a given position, the averaged evaporation flux in rectangular capillaries is much larger than that in circular capillary with comparable hydraulic diameter. The flow near the evaporating meniscus is also measured using micro-PIV, so that the rotating vortex motion is observed near the evaporating ethanol and methanol menisci except for the case of methanol meniscus in rectangular capillary. This difference is considered to be due to the existence of corner menisci at the four comers.

• 대한한의학원전학회지
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• 제28권1호
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• pp.143-150
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• 2015

Objectives : This study aim to find out the reason why perspiration related with the Heart in Korean Medicine. Results : Perspiration is closely connected with the Heart because sweat is a kind of ultrafiltrate of the blood and the Heart conducts blood. In order to perspire, it is necessary to increase blood flow to capillary surrounding sweat glands. The Heart plays an important role in increasing blood flow to capillary surrounding sweat glands. Perspiration controls the body temperature. It must be increase the blood flow to skin in order that down the high body temperature. The Heart plays an important role in increasing blood flow. Conclusions : Perspiration is closely connected with the Heart because sweat is a kind of ultrafiltrate of the blood and there are plenty capillary surround sweat gland. The Heart controls the blood flow to skin in order to regulate of body temperature.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권1호
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• pp.1-5
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• 2016

Capillary barriers, consisting of relatively fine-over-coarse materials, have been suggested as an alternative to traditional compacted soil covers. So, We were analysed to capillary barrier effect according to five cases of multi-layer cover systems. Water balance simulation was conducted with unsaturated flow model HELP to assess unsaturated hydraulic parameters such as hydraulic conductivity, climate affecting the performance of capillary barriers. Simulation were conducted for 5 Cases in the Ulsan area. Result of simulation indicated that three cases was formed unsaturated condition and capillary barrier effect.

• 반도체디스플레이기술학회지
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• 제18권2호
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• pp.6-10
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• 2019

In the presence of $\mu-tip$ for narrow stripe coating, there appears lateral capillary flow along the hydrophilic head lip because the $\mu-tip$ has some resistance to flow. It was known to be suppressed by increasing the contact angle of the head lip. In this paper, we have demonstrated by computational fluid dynamics(CFD) simulations that it can also be suppressed by the formation of micro-patterns on the shim and meniscus guide embedded into the slot-die head. To optimize the micro-patterned structure, we have performed simulations by varying the groove width, depth, and clearance. In the absence of micro-patterns, it is shown by experiment and simulation that the solution spreads to a distance of $1,300{\mu}m$ from the ${\mu}-tip$. In the presence of micro-patterns with the groove width and clearance of $50{\mu}m$, the distance the solution spreads is reduced to $260{\mu}m$. However, no further suppression in the capillary flow is observed with micro-patterns with the groove width of $40{\mu}m$ or less. It is also observed that the capillary flow is not affected by the groove depth if it is larger than $10{\mu}m$. We have shown that the distance the solution spreads can be reduced further to $204{\mu}m$ by coating a hydrophobic material (contact angle of $104^{\circ}$) on the surface of micro-patterns having the groove width and clearance of $50{\mu}m$.

• 대한기계학회논문집B
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• 제30권2호
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• pp.110-116
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• 2006

A syringe pump or a device using high electric voltage has been used for controlling flows inside a LOC (lab-on-a-chip). Compared to LOC, however, these microfluidic devices are large and heavy that they are burdensome for a portable ${\mu}-TAS$ (micro total analysis system). In this study, a new flow control technique employing pressure regulators and pressure chambers was developed. This technique utilizes compressed air to control the micro-scale flow inside a LOC, instead of a mechanical actuator or an electric power supply. The pressure regulator controls the output air pressure by adjusting the variable resistor attached. We checked the feasibility of this system by measuring the flow rate inside a capillary tube of $100{\mu}m$ diameter in the Re numbers ranged from 0.5 to 50. In addition, the performance of this flow control system was compared with that of a conventional syringe pump. The developed flow control system was found to show superior performance, compared with the syringe pump. It maintains automatically the: air pressure inside a pressure chamber whether the flow inside the capillary tube is on or off. Since the flow rate is nearly proportional to the resistance, we can control flow in multiple microchannels precisely. However, the syringe pump shows large variation of flow rate when the fluid flow is blocked in the microchannel.

• 분석과학
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• 제12권6호
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• pp.521-527
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• 1999

본 연구에서는 적은 양의 시료를 분석할 수 있는 이온 크로마토그래피용 모세관 컬럼을 개발하였다. 내경이 작은 모세관 컬럼을 사용하는 경우 이동상의 유속은 보통 $5{\sim}15{\mu}L/min$ 정도 되고 컬럼의 길이는 50~150 mm 정도이다. 컬럼은 RSL-300 fused silica 모세관(내경 : 0.53 mm, 외경 : 0.67 mm)과 AG14 column resin(support : polystyrene-divinylbenzene, functional group : aulkyl quatemary ammonium)을 이용하여 만들었다. 또한 이런 모세관 컬럼에 맞는 새로운 전도도 셀과 억제컬럼도 함께 개발하여 사용하였다. 이 모세관 컬럼을 이용하여 실제 음이온들(fluoride, nitrite, nitrate, chlorate)을 분석한 결과 재현성 있고 좋은 크로마토그램을 얻었다.

• Journal of the Korean Wood Science and Technology
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• 제46권6호
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• pp.681-691
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• 2018

The typical methods of mercury intrusion porosimetry (MIP) and capillary flow porometry (CFP) were used to evaluate the pore size of cross-section of wood and the effect of the pore structure on the permeability of wood was analyzed in this study. The results of this study were as followings: The pore size of wood measured by CFP was larger than that measured by MIP except for Lime tree, Korean red pine and Paulownia. Among the three pore types of porous materials defined by IUPAC (through pores, blind pores, and closed pores), only through pores are related to permit fluid flow. MIP measures the pore size of both through pores and blind pores, while CFP measures the pore size of only constricted through pores. Therefore, pore size measured by MIP was not related to gas permeability, however pore size measured by CFP had a proportional relationship with gas permeability.