• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.6
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• pp.1538-1542
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• 2006

The study was designed to investigate the effects of MokhwyangJoki-san Extract (MJSE) on the change of regional cerebral blood flow (rCBF) and mean arterial blood pressure (MABP) in normal rats, and further to determine the mechanism of MJSE. The results in normal rats were as follows ; MJSE significantly increased rCBF in a dose-dependent manner, and MABP did not change in a dose-dependent manner. This results were suggested that MJSE significantly increased rCBF by dilating pial arterial diameter. The MJSE-induced increase in rCBF was significantly inhibited by pretreatment with methylene blue (10 ${\mu}g/kg$, i.p.), an inhibitor of guanylate cyclase, and was not changed by indomethacin (1 ${\mu}g/kg$, i.p.), an inhibitro of cyclooxygenase. The MJSE-was not changed MABP was decreased by pretreatment with indomethacin but was not changed by methylene blue. This results were suggested that the mechanism of MJSE was mediated by guanylate cyclase.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.227-232
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• 1996

The one-third calibrating relation by steady solution can cause large error when applied to an unsteady flow with large amplitude waves. Extended calibrating method, which can treat the normal convective contribution, is developed. The normal mass convective term is included into the 2-D mass transport equation by means of rms value and random function. The unknown shear rate is numerically determined by solving the 2-D mass transport equation inversely. This recovery method which predicts the unknown shear rate is constructed. It is found that it works very well without distortion. The inclusion of the normal convective term has a negligible effect on the mass transfer coefficient.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.12
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• pp.3166-3178
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• 1993

The turbulent flow characteristics of impinging jet have been investigated by the hot wire anemometry with a movable impinging wall. Turbulences were generated by the meshed jet as well as the typical round jet and their characteristics were compared, of mean velocity profiles, turbulent intensities. Reynolds stresses, similarities and their centerline flow behaviors. The meshed jet tends to make shear layer wider than the normal one in the initial region and the velocity profiles of the normal jet is rather contractive being compared with those of the meshed one near the wall. The effect of meshed exit appears only within 4D at the begining of jets and the cascading process of the meshed one marches more rapidly than that of the normal jet. The wall effects appear in the downstream of about 0.85 H to the impinging wall for every case of wall positions in both nozzles.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.45-48
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• 2005

Self compacting concrete has the strong point in capability of concrete to be uniformly filled and compacted in every corners of formwork by its self-weight without vibration during placing. However, powder type self compacting concrete has the weak point in the heat of hydration, the drying shrinkage and the elastic property of concrete etc. Recently viscosity agent has been developed in order to overcome these weaknesses. In this study, self compacting concrete is made with viscosity agent based on polysaccharide derivative in order to develope the normal strength self compacting concrete. Slump flow, loss of slump flow and setting time are measured for comparison with normal concrete. Compressive strength, freezing and thawing test and carbonation test are conducted on normal and self compacting concrete using viscosity agent. In the experiment, we acquired good results in fresh and hardened self compacting concrete using viscosity agent based on polysaccharide derivative.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.7
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• pp.2289-2297
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• 1996

Flows in the combustion chamber near the spark plug are measured using LDv.A single cylinder DOHC S.I. engine of compression ratio 9.5:1 with a transparent quartz window piston is used. Combustion chamber shape is semi-wedge type. Measured data are analyzed using the ensemble averaged analysis and the cycle resolved analysis which uses FFT Filtering. Turbulent intensity and mean velocity are studied in the main flow direction and the normal to main flow direction as a function of engine speeds. The results shows that the turbulent intensity obtained by the ensemble averaged analysis is greater than that calculated by the cycle resolved analysis. Especially, the ensemble averaged analysis shows increase in turbulence at the end of compression stroke although the cycle resolved analysis shows increase only in the cycle-by-cycle variation with no noticeable increase in turbulence. The mean velocity in the main flow direction increase as engine speed increase. But the mean velocity normal to the main flow does not show such increase. Turbulent intensity in both direction increase in proportion to engine speeds. The magnitude of turbulent intensity is about 0.3 ~ 0.4 times the mean piston speeds at the end of the compression stroke.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.10
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• pp.1285-1293
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• 2000

In port fuel injection system of SI engines, injected fuel is impinged onto the surface of intake valves and port-wall, and then formed the wall flow under the cold start operation. Wall flows entrained into the cylinder result in the unsteady and nonuniform mixture formation. Therefore, the spray impingement to the wall is considered as having negative influences such as lowering combustion efficiency and causing unburned hydrocarbon emissions. This study investigates the spray characteristics of the wall impinging air-assist spray in suction air flow. A PDPA was used to analyze the flow characteristics under the different conditions such as impingement angle and supplied air. Experimental data concerning the impinging sprays has been obtained in the vicinity of the wall. Measured droplets divided into the pre-impinging droplets which denote as the positive normal velocities and post-impinging droplets that describe as the negative normal velocities for the suction flow. Their velocities, size distributions and SMD are comparatively analyzed before and after the impingement.

• Progress in Medical Physics
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• v.9 no.1
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• pp.23-28
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• 1998

We measured the flow at peripheral blood vessel of finger dorsum surface using noninvasive LDF(Laser Doppler Flowmeter). We investigated the flow properties between the normal and the diabetic with the Amplitude Spectral Densities of FFT analysis. We classified the diabetic as four groups of negative neuropathy, positive neuropathy, hyperthyroid and hypothyroid. And tested the neuropathic and thyroid effects of peripheral blood flow. As the results, the diabetic, the positive neuropathic and the hypothyroid respectively showed the abnormal blood flow properties on the contrary of the normal flow of negative neuropathic and hyperthyroid.

• Journal of the Korean Society of Industry Convergence
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• v.2 no.2
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• pp.115-124
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• 1999

The interaction of weak normal shock wave with turbulent boundary layer in a supersonic nozzle was investigated experimentally by wall static pressure measurements and by schlieren optical observations. The lime-mean flow in the interaction region was classified into four patterns according to the ratio of the pressure $p_k$ at the first kink point in the pressure distribution of the interaction region to the pressure $p_1$ just upstream of the shock. It is shown for any flow pattern that the wall static pressure rise near the shock foot can be described by the "free interaction" which is defined by Chapman et al. The ratio of the triple point height $h_t$ of the bifurcated shock to the undisturbed boundary layer thickness ${\delta}_1$ upstream of the interaction increases with the upstream Mach number $M_1$, and for a fixed $M_1$, the normalized triple point height $h_t/{\delta}_1$ decreases with increasing ${\delta}_1/h$, where h is the duct half-height.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.318-318
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• 2012

인도네시아의 Citarum 유역을 대상으로 구축된 RRFS를 이용하여 해당유역의 상류에 위치한 다목적 댐인 Saguling 댐에 대한 2005년 월 유입량예측을 수행하여 보았다. 실제 예측과정에는 ESP 기법을 적용하였고 여기에 기상전망을 고려할 수 있는 사전처리기법인 PDF ratio 방법을 이용하여 유출량 시나리오의 발생확률을 갱신하였다. 이를 위하여 대상유역의 월 강우량 관측 자료에 대한 초보예측을 통하여 2005년 관측 강우량에 따라 기상전망을 생성하였다. 또한 Saguling 댐의 월 유입량 과거 관측자료에 대한 초보예측을 통하여 High Flow, Normal Flow, Low Flow에 대한 예측구간을 구성하여 보았다. Fig. 1과 Fig. 2는 각각 ESP 기법과 PDF ratio 방법을 이용하여 산정한 Normal Flow와 Low Flow의 상한계 유입량의 발생확률의 변화를 도시한 것이다. 관측 유입량이 발생한 구간의 예측확률을 기반으로 예측점수를 산정해 본 결과 ESP 기법에 의한 예측점수가 0.333을 상회하고 있음을 볼 수 있었다. 이는 ESP 기법에 의한 예측결과가 초보예측보다 정확도가 높음을 의미하는 것으로 본 연구에서 구성한 ESP 시스템의 적용성을 확인할 수 있다. 또한 고무적인 결과로서 PDF ratio 방법에 의한 예측점수가 ESP 기법에 의한 예측점수를 상회하고 있음을 확인할 수 있다. 이는 ESP 기법에 의한 예측결과를 확률기상전망을 이용하여 갱신할 경우 예측 정확도를 개선시킬 수 있음을 의미하는 것이다.

• Journal of Korean Society on Water Environment
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• v.34 no.5
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• pp.462-469
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• 2018

There are differences in method and cycle of flow rate survey depending on purpose of the operating department. To verify and use results of flow data according to the purpose, flow data of the directly measured and tele monitoring system were compared to verify validity. Flow measurement in the Ministry of Environment is aimed at setting up a standard flow of target water quality for water quality management and securing flow data of low and normal water level seasons for water quality evaluation. In this study, correlation analysis result ($R^2$) of same time zone data by direct measurement and tele monitoring system (TMS) at Seombon D point, a unit watershed of Seomjin river, for six years ('10 ~ '15) according to implementation of Total Daily Maximum Load (TDML) was wading 0.716, boating 0.962 and on bridge 0.943, and effectiveness of measurement method was verified by characteristics of flow duration as a season of dry and low-water; normal and high water are appropriate for wading, boating, and on bridge respectively. Results revealed it is reasonable to use directly measured results using the wading and boating method for low water level and dry seasons, and TMS data for rainy seasons. It can be used important data for future policy decisions.