• Bulletin of the Korean Chemical Society
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• 제14권2호
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• pp.250-255
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• 1993

A dual capillary column system is described for the simultaneous analysis of a given sample and measurement of retention index (RI) and area ratio (AR) values of each peak on two capillary columns of different polarity, DB-5 & DB-1701 from a single injection. Both capillary columns were connected to either a splitless injector or an on-column injector via a deactivated fused-silica capillary tubing of 1 m length and a 'Y' splitter. Both injection modes allowed to measure RI and AR values with high reproducibility (<0.01% RSD) and high accuracy (<10% RE), respectively with the exception that the trace and high boiling solutes required the on-column mode for the accurate quantification and AR comparison. When the dual capillary column system in on-column injection mode was applied to the blind samples containing organic acids, each acid was positively indentified by the combined computer RI library search-AR comparison.

• Mass Spectrometry Letters
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• 제2권3호
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• pp.65-68
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• 2011

The effects of column length and particle size on the efficiency of separation and characterization of phospholipids (PLs) are investigated using nanoflow liquid chromatography-electrospray ionization-tandem mass spectrometry (nLC-ESI-MS-MS). Since PLs are associated with cell proliferation, apoptosis, and signal transduction, it is of increasing interests in lipidomics to establish reliable analytical methods for the qualitative and quantitative profiling of PLs related to biomarker development in adult diseases. Due to the complexity of PLs, the preliminary separation of PLs is necessary prior to MS analysis. In this study, length of capillary column and the particle size of reversed phase ($C_{18}$) packing materials are varied to find a reliable condition for the high speed and high resolution separation using 8 PL standard mixtures. From experiments, it was found that a capillary column of nLC-ESI-MS-MS analysis for PL mixtures can be minimized to a 5 cm long pulled tip column packed with 3 ${\mu}m$ $C_{18}$ particles without losing resolution.

• 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.

• 설비공학논문집
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• 제8권2호
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• pp.177-186
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• 1996

The characteristics of the flow of pure HFC refrigerants(R32, R125, and R134a) and their mixtures through capillary tubes were investigated experimentally. Two capillary tubes with 1.2mm and 1.6mm inner diameter and 1.5m length were adopted as test sections. Mass flow rates and temperatures and pressures were measured for several condensing temperatures and degrees of subcooling at capillary tube inlet. The effects of the condensing temperature, inner diameter of capillary tube, and subcooling on the mass flow rate of refrigerants were discussed, and the mass flow rates of HFC refrigerants were compared with that of R22. The pressure and temperature distributions along the capillary tube compared with that of R22. The pressure and temperature distributions along the capillary tube show that there is a metastable equilibrium state in the flow through the tube. Underpressure for vaporization increases as refrigerant mass flux increases and inlet subcooling decreases. Empirical correlation was suggested to predict underpressure for vaporization of the HFC refrigerants.

• 한국수소및신에너지학회논문집
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• 제19권6호
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• pp.537-544
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• 2008

In this paper, flow characteristics of an adiabatic capillary tube in a transcritical $CO_2$ have been investigated employing the homogeneous model. The model is based on fundamental equations of mass, energy and momentum which are solved simultaneously. Two friction factors(Churchill) and viscosity(McAdams) are comparatively used to investigate the flow characteristics. Supercritical and subcritical thermodynamic and transport properties of $CO_2$ are calculated employing EES property code. Flow characteristics analysis of $CO_2$ adiabatic capillary tube is presented to offer the basic design data for the operating parameters. The operating parameters considered in this study include inlet temperature and pressure of an adiabatic capillary tube, evaporating temperature and inner diameter tube. The main results were summarized as follows : inlet temperature and pressure of an adiabatic capillary tube, evaporating temperature, mass flowrate and inner diameter of $CO_2$ adiabatic capillary tube have an effect on length of an adiabatic capillary tube.

• 태양에너지
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• 제19권2호
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• pp.21-28
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• 1999

This study was carried out to investigate the effect of energy transport using capillary pumped loop with PVA sponge wick. The results obtained from this study are as follows. The configuration of capillary pumped loop was adequate and PVA sponge was of great use for the manufacture of capillary pump. The energy transport reached maximum when the working fluid amount was 750cc the wall temperature distribution indicated high values through out the entire length of the pipe. As the opening of a nozzle was increased, energy transport was increased but the effect was decreased.

• Bulletin of the Korean Chemical Society
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• 제12권1호
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• pp.87-92
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• 1991

A dual capillary column system is described for the simultaneous measurement of retention index (RI) and area ratio (AR) values of each peak on two capillary columns of different polarity, DB-5 & DB-1701. Both capillary columns were connected to a common splitless injector via a deactivated fused-silica capillary tubing of 1 m length and a 'Y' splitter, the dead volume effect of which was found to be negligible. RI and AR were measured with high reproducibility(${\leq}$0.05% RSD) and with high accuracy (<10% RE), respectively. When applied to the test samples of the organic acid mixture, each acid was positively identified by the combined computer RI library search-AR comparison.

• 한국세라믹학회지
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• 제22권5호
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• pp.23-28
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• 1985

A model for degradation of $eta$-$Al_2O_3$ is derived from sress generated by Poiseuille pressure capillary effect and effulent flux in charging process of Na-S Battery. Critical current density for degradation increase with increasing the crack length and crack tip radius. radius 10-7cm and crack length 10-5cm Dependence of crack growth velocity on crack lengh is seperated two regions that is for a large crack length it is predominated by Poiseuille pressure and effulent fluex but in the case of small crack length it is controlled by capillary effect.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2142-2147
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• 2007

Experimental study was conducted to evaluate the performance of a miniature loop heat pipe (MLHP) with non-inverted meniscus type capillary structure. All parts of MLHP in this study were made of copper including the capillary structure and the distilled water was used as a working fluid of MLHP. The outer diameter of evaporator was 9 mm and its length was 119 mm. The effective pore size of the capillary structure was 30 micron and its porosity was 60%. The vapor transport line, the liquid transport line and the condenser were consisted of single 4.0 mm copper tube. The distance between the evaporator and the condenser region was 200 mm and the length of the loop was 969 mm. This MLHP was operated successfully at any orientation but the gravity highly influenced the thermal performance of the MLHP. The maximum thermal load was 130 watts at the bottom heat mode and the 20 watts at the top heat mode.

• 반도체디스플레이기술학회지
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• 제18권1호
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• pp.92-96
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• 2019

In the presence of ${\mu}-tip$ embedded in a slot-die head for stripe coatings, there arises the capillary flow that limits an increase of the stripe density, which is required for the potential applications in organic light-emitting diode displays. With an attempt to suppress it, we have employed a computational fluid dynamics software and performed simulations by varying the ${\mu}-tip$ length and the contact angles of the head lip and ${\mu}-tip$. We have first demonstrated that such a capillary flow phenomenon (a spread of solution along the head lip) observed experimentally can be reproduced by the computational fluid dynamics software. Through simulations, we have found that stronger capillary flow is observed in the hydrophilic head lip with a smaller contact angle and it is suppressed effectively as the contact angle increases. When the contact angle of the head lip increases from $16^{\circ}$ to $130^{\circ}$, the distance a solution can reach decreases sharply from $256{\mu}m$ to $44{\mu}m$. With increasing contact angle of the ${\mu}-tip$, however, the solution flow along the ${\mu}-tip$ is disturbed and thus the capillary flow phenomenon becomes more severe. If the ${\mu}-tip$ is long, the capillary flow also appears strong due to an increase of flow resistance (electronic-hydraulic analogy). It can be suppressed by reducing the ${\mu}-tip$ length, but not as effectively as reducing the contact angle of the head lip.