• Proceedings of the Materials Research Society of Korea Conference
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• 2007.05a
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• pp.27.2-27.2
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• 2007

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.976-981
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• 2006

In case of attaching thermoelectric module and heat source, the polymer pad is attached on the $Al_2O_3$ plate, which is cooling side of thermoelectric module, in order to enhance mechanical safety of the system. It is impossible to calculate the exact distribution of temperature and flow pattern of inner gap of thermoelectric module. Therefore CFD(Computational Fluid Dynamics) analysis was executed to determine the thermo-fluid phenomena and distribution by Fluent. As the result of these analysis, heat transfer was dominated by conduction and the difference of temperature was linear distribution according to the thickness of polymer sheet.

• The Journal of Internal Korean Medicine
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• v.26 no.3
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• pp.596-604
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• 2005

Objectives : Geopungjeseub-tang(Gufengchushi-tang) has been used in oriental medicine for many centuries as a therapeutic agent for hemiplegia caused by deficiency of qi(氣虛) and damp phlegm(濕痰). This study was performed to evaluate effects of Geopungjeseub-tang extract(GJT) on hemodynamics[regional cerebral blood flow(rCBF), pial arterial diameter(PAD), mean arterial blood pressure(MABP), heart rate(HR)] in normal rats and in rats with cerebral ischemia by middle cerebral artery(MCA) occlusion. Also, effects of adrenergic ${\beta}-receptor$, cyclooxygenase on response to GJT were evaluated. Methods : Laser-doppler flowmetry(LDF) measured changes of rCBF, MABP and HR. Video microscope and width analyzer measured changes in PAD. Results : rCBF and PAD increased after treatment with GJT(10mg/kg, i.v.) during the period of cerebral reperfusion, and pretreatment with indomethacin raised rCBF and PAD increased after treatment with GJT during the same period as above. Pretreatment with propranolol decreased rCBF, but increased after GJT treatment, but raised PAD increased after GJT treatment during this period of reperfusion. Conclusion : CR caused diverse responses were observed in rCBF and PAD after treatment with GJT. ACF action is mediated by adrenergic ${\beta}-receptor$ and cyclooxygenase. Result suggest that GJT has an anti-ischemic effect through the improvement of cerebral hemodynamics and has theraputic potential for cerebral apoplexy.

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.100-105
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• 2021

This paper proposes the polydimethylsiloxane (PDMS) blade coating method for fabrication of paper-based analytical device (PAD) that is able to monitor the disease diagnosis and progress without special analytical equipment. The mold that has PAD design is easily modified by using laser cutting technique. And the fabricated mold is used for hydrophobic barrier formation by blade coating. We have optimized the stable formation of PDMS hydrophobic barrier as blade coating condition, which is established by analyzing the structure of the PDMS hydrophobic barrier and change of hydrophilic channel size as thickness of the ink and contact time with the chromatography paper. Based on optimal condition, we demonstrate that PAD as biosensor can apply to detect protein, glucose, and metal ion without special analysis equipment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.47-48
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• 2007

A CMP Process has many factors that affect result of a polished wafer. Dominant factors are velocity, pressure and temperature in process. A pad profile is also considered as affecting factor of CMP. Accoding to variation of a pad profile, the each pan of a wafer is differently pressured. It appears to affect the uniformity of a wafer. A pad profile varies as a swing arm conditioner which have been ordinarily used in industry. A swing arm conditioner has several sectors in its swing path. This study aims that a wafer get a good uniformity as swing arm conditioner's path on pad is analyzed and simulated. Through the simulation, tendency of pad profile after conditioning will be predicted and the result of simulation compared with the result of experiment. The optimized pad profile would be made by to vary swing arm's velocity on each sector. In order to maintain the optimized profile, conditioner design or swing arm's velocity should be changed and designed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.2
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• pp.131-140
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• 2022

Installing Continuous Welded Rail (CWR) is one of the economical ways to resolve the challenges of noise, vibration, and the open-deck steel railway bridge impact, and the SSF method using the interlocking sleeper fastener has recently been developed. In this study, the method employed for determining the optimum vertical stiffness of the sleeper pad installed under the bridge sleeper, which is utilized to adjust the rail height and absorb shock when the train passes when the interlocking sleeper fastener is applied, is presented. To determine the optimal vertical stiffness of the sleeper pad, related existing design codes are reviewed, and, running safety, ride comfort, track safety, and bridge vibration according to the change in the vertical stiffness of the sleeper pad are estimated via flexible multi-body dynamic analysis,. The flexible multi-body dynamic analysis is performed using commercial programs ABAQUS and VI-Rail. The numerical analysis is conducted using the bridge model for a 30m-long plate girder bridge, and the response is calculated when passing ITX Saemaeul and KTX vehicles and freight wagon when the vertical stiffness of the sleeper pad is altered from 7.5 kN/mm to 240 kN/mm. The optimum stiffness of the sleeper pad is calculated as 200 kN/mm under the conditions of the track components applied to the numerical analysis.

• The Journal of the Convergence on Culture Technology
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• v.10 no.3
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• pp.833-838
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• 2024

The urban railway sleeper floating track(STEDEF) is a structure that structurally separates the sleepers and the concrete bed using sleeper boots and resilience pads to reduce vibration transmitted to the concrete bed. Recently, the resilience pads of sleeper floating tracks that have been in use for more than 20 years are deteriorating. Accordingly, in order to evaluate the performance of the resilience pad, a static spring stiffness test is being performed after extracting the resilience pad. This evaluation technique is performed after replacing the resilience pad in use. However, the track natural frequency can change depending on the resilience pad spring stiffness and the uplift and subsidence of the concrete bed. In this study, modal testing technique was used to evaluate the track natural frequency. For this purpose, the sleeper boots material, resilience pad spring stiffness, and track natural frequency according to concrete bed uplift and subsidence were measured using modal tests at a laboratory scale. It was analyzed that the natural frequency of the sleeper floating track was directly affected by changes in the spring stiffness of the resilience pad. In addition, the change in natural frequency due to the uplift and subsidence of the concrete bed was also found to be large. Therefore, it is believed that the modal test technique presented in this study can be used to evaluate the resilience pad deterioration and voided sleepers.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.4
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• pp.1014-1020
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• 2004

The study was designed to investigate the effects of Palmul-Tang(PMT) on the change of cerebral hemodynamics [regional cerebral blood flow(rCBF), pial arterial diameter(PAD) and mean arterial blood pressure(MABP)] in normal and cerebral ischemic rats. The change of rCBF and MABP were determinated by laser-doppler flowmetry(LDF), and the change of PAD was determinated by video-microscopy. The results in normal rats were as follows ; PMT significantly increased rCBF and PAD in a dose-dependent, and PMT increased MABP in a dose-dependent. This results were suggested that PMT significantly increased rCBF by dilating PAD. The results in cerebral ischemic rats were as follows ; Both rCBF and PAD were significantly and stably increased by PMT(10㎎/㎏, i.p.) during the period of cerebral reperfusion, which contrasted with the findings of rapid and marked increase in control group. The present authors thought that PMT had an anti-ischemic effect through the improvement of cerebral hemodynamics.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.8 s.173
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• pp.27-33
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• 2005

Polishing pads play an important role in chemical mechanical polishing(CMP) which has recently been recognized at the most effective method to achieve global planarization. In this paper, we have investigated CMP characteristics as a change of groove density of polishing pads. The parameter $(K_n)$ is proposed to estimate groove density of pad. The $K_n$ is defined as groove area divided by pitch area. As the groove density value increased, removal rate increased to some point and then gradually saturated in case of increasing the groove density excessively. In addition Within wafer non-uniformity(WIWNU) worse as groove density increased excessively, although WIWNU improved as groove density increased. Also the uniformity of temperature of pad surface decreased as the groove density increased. It was because that the cooling effect increased as groove density increased. In other words, increasing the groove density which means the apparent contact area of pad has influence on amount of discharge of slurry during polishing process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.7
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• pp.568-574
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• 2000

We have been optimized tungsten(W) plug CMP(chemical mechanical polishing) characteristics using two different kinds of component of slurry and two different kinds of pad which have different hardness. The comparison of oxide film roughness on around W plug after polishing has been carried out. And W plug recess for consumable sets and dishing effect at dense area according to the rate of over-polishing has been investigated. Also the analysis of residue on surface after cleaning have been performed. As a experimental result we have concluded that the consumable set of slurry A and hard pad was good for W plug CMP process. After decreasing the rate of chemical reaction of silica slurry and adding two step buffering we could reduce the expanding of W plug void however we are still recognizing to need a more development for those kinds of CMP consumables.