• Wind and Structures
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• v.29 no.4
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• pp.235-246
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• 2019

Wind loading is one of important loadings that should be considered in the design of large hyperbolic natural-draught cooling towers. Both external and internal surfaces of cooling tower are under the action of wind loading for cooling circulating water. In the previous studies, the wind loads on the external surface attracted concernedly attention, while the study on the internal surface was relatively ware. In the present study, the wind pressure on the internal surface of a 220 m high cooling tower is measured through wind tunnel testing, and the effect of ventilation rate of the packing layer on internal pressure is a major concern. The characteristics of internal wind pressure distribution and its effect on wind-induced responses calculated by finite element method are investigated. The results indicate that the wind loading on internal surface of the cooling tower behaves remarkable three-dimensional effect, and the pressure coefficient varies along both of height and circumferential directions. The non-uniformity is particularly strong during the construction stage. Analysis results of the effect of internal pressure on wind-induced responses show that the size and distribution characteristics of internal pressure will have some influence on wind-induced response, however, the outer pressure plays a dominant role in the wind-induced response of cooling tower, and the contribution of internal pressure to the response is small.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.573-576
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• 2006

The objective of the study is to investigate the depth of penetration of concrete water forced in under pressure. For this purpose, the experiments for the depth of penetration by selecting the factors and levels such as water pressure, pressure time were executed. The flow of water of concrete examined theoretically and experimentally. As a result, It is found that in the case of low water pressure approximately 0.15Mpa or less, the flow is Darcy seepage flow, the same as flow in an ordinary sand stratum, whereas in the case of high water pressure, the flow is diffused seepage flow accompanied by internal deformation of concrete.

• The Journal of Internal Korean Medicine
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• v.15 no.1
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• pp.80-98
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• 1994

According to the original documents, Sagungsan is considered as an effective drug for controlling the hypertensive epistaxis induced by tension of autonomic nerve and it's hyperfunction. The present experiment was designed to understand the effect of Sagungsan extract on the hemostatic action, intracranial pressure, blood pressure and cardiovascular system in experimental animals. And thus the bleeding time, prothrombin time, capillary dilation, blood pressure, Intracranial pressure, and enzymatic analysis of the ATPase activities were studied. The result obtained here were as followings: 1. Sagungsan water extract reduced the bleeding time in mouse, and prolonged the prothrombin time in rabbits. 2. The drug extract increased the tail volume by capillary dilation in rats. 3. The drug extract inhibited the increase of intracranial pressure and arterial blood pressure in rabbits. 4. At the early time, the increase of arterial blood pressure by the drug extract significantly inhibited by pretreated atropin and regitine in rabbits. 5. The drug extract relaxed the smooth muscle by stimulating the Mg2+-Ca2+-ATPase activities of gastric sarcoplasmic reticulum isolated from rabbit stomach. 6. The drug extract stimulated the heart contraction by inhibiting the $Mg^{2+}-Ca^{2+}-ATPase$ activities of cardiac sarcoplasmic reticulum isolated from rabbit heart. The inhibitory mechanism was reversible and noncompatitive. 7. The drug extract increased the hepatic blood volume by stimulating the hepatic total ATPase activities and hepatic metabolism. 8. The drug extract acted as a tranquilizer by inhibiting the neural Na+-K+-ATPase activity. According to the results, Sagungsan water extract dilated the capillaries, stimulated the heart beat, and thus increased the blood flow with decreasing the intracranial pressure and blood pressure. These effects stanches the epistaxis collectively.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.17-20
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• 2005

In-situ structural health monitoring of filament wound pressure tanks were conducted during water-pressurizing test using embedded fiber Bragg grating (FBG) sensors. We need to monitor inner strains during working in order to verify the health condition of pressure tanks more accurately because finite element analyses on filament wound pressure tanks usually show large differences between inner and outer strains. Fiber optic sensors, especially FBG sensors can be easily embedded into the composite structures contrary to conventional electric strain gages (ESGs). In addition, many FBG sensors can be multiplexed in single optical fiber using wavelength division multiplexing (WDM) techniques. We fabricated a standard testing and evaluation bottle (STEB) with embedded FBG sensors and performed a water-pressurizing test. In order to increase the survivability of embedded FBG sensors, we suggested a revised fabrication process for embedding FBG sensors into a filament wound pressure tank, which includes a new protecting technique of sensor heads, the grating parts. From the experimental results, it was demonstrated that FBG sensors can be successfully adapted to filament wound pressure tanks for their structural health monitoring by embedding.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.8
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• pp.1203-1210
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• 2004

It was reported recently that the pump head degradation near the best efficiency point from single-phase flow to the break-down due to air entrainment became less in a screw-type centrifugal pump than in a general centrifugal pump. In this paper, I carried out internal pressure measurements and visualizations, and investigated the various physical phenomena occurring inside a screw-type centrifugal pump operated in air-water two-phase flow. The results could give some characteristics about the degradation of pump performance on air-water two-phase flow.

• The Journal of Internal Korean Medicine
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• v.21 no.3
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• pp.417-424
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• 2000

Objective : The purpose of this study was to investigate the effects of Sasim-tang water extract on the cardiovascular systems including changes of blood pressure and regional cerebral blood flow volume (rCBF) in male Sprague-Dawely rats. Methods : The changes of blood pressure were recorded by data acquisition system composed of MacLab and Macintosh computer. The changes of rCBF were observed by Laser-Doppler flowmetry through a opened cranial window. Results : 1. The changes of blood pressure was not affected by Sasim-tang extract intravenous injection in rats. 2. After pretreatment with propranolol(3mg/kg), L-NNA(10mg/kg) and 000(10mg/kg), the changes of blood pressure was not affected by Sasim tang extract intravenous injection in rats. 3. The changes of rCBF was increased in dose-dependent manner by Sasim-tang extract intravenous injection in rats. 4, After pretreatment with propranolol(3mg/kg), ODQ(10mg/kg) and L-NNA(10mg/kg), rCBF was significantly decreased in dose- dependent manner by Sasim-tang extract intravenous injection in rats. Conclusions : These results suggest that Sasim-tang was related to the regulation of the sympathetic nerve system, nitric oxide synthesis and synthesis of cyclic GMP.

• Structural Engineering and Mechanics
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• v.80 no.5
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• pp.553-562
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• 2021

In this paper, a hybrid scaled boundary finite element and finite volume method (SBFEM-FVM) is proposed for simulating hydraulic-fracture propagation in brittle concrete materials. As a semi-analytical method, the scaled boundary finite element method is introduced for modelling concrete crack propagation under both an external force and water pressure. The finite volume method is employed to model the water within the crack and consider the relationship between the water pressure and the crack opening distance. The cohesive crack model is used to analyse the non-linear fracture process zone. The numerical results are compared with experimental data, indicating that the F-CMOD curves and water pressure changes under different loading conditions are approximately the same. Different types of water pressure distributions are also studied with the proposed coupled model, and the results show that the internal water pressure distribution has an important influence on crack propagation.

• Journal of Korean Society on Water Environment
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• v.18 no.2
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• pp.131-140
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• 2002

Laboratory-scale membrane bioreactor added alum into the anaerobic basin as a flocculant and adsorbent was carried out to find removal efficient of nitrogen and phosphorus components in the mixed liquid and weather or not maintaining the stability for the permeate flux and pressure at various internal recycle conditions. It was found that denitrification efficient of maximum 65% was obtained when the ratio of internal recycle was 3Q. Additionally when the ratio of internal recycle was fixed at 3Q, $BOD_5$ and T-P concentration of permeate was much more reduced compared to not added alum in anaerobic basin but T-N concentration of permeate was relatively increased. In case of added alum as the flocculant and adsorbent in anaerobic basin, the permeate flux was maintained above $10{\ell}/m^2/hr$ but the permeate pressure was relatively higher than alum was not added in anaerobic basin.

• The Journal of Internal Korean Medicine
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• v.17 no.1
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• pp.34-50
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• 1996

The present experiment was desinged to investigate the effects of Tongdosan water extracts on the Cardiovascular System in the Experimental Animals. Thus, the changes of blood pressure and heart rate were measured after oral admini- stration. Measurment of Mortality rate was observed for measuring the effect of Tongdosan water extract. Tongdosan water extract against pulmonary thrombo- embolism induced by collagen the mixture(0.1ml/10g, 2mg/kg B.W) plus serotonin(5mg/kg B.W) in mouse. The effect of Tongdosan water extract was examined by observing the change of collagen-induced platelet aggregation, coagulation activity, ex vivo and in vitro fibrinolytic activity of euglobulin fraction in rats. The results were summarized as followings. 1. Tongdosan dropped the blood pressure in spontaneous hypertensive rat. 2. The drug increased the auricular blood flow in rabbit. 3. The drug relaxed the artery contraction by pretreated norepinephrine in rat. 4. The drug inhibited the death rate of mouse which was led to thromboembo- lism by serotonin and collagen. 5. The drug inhibited the platelet aggregation in rat. 6. The drug prolonged the prothrombin time and activated partial thromboplastin time on the test of plasma coagulation factor activity in rat, but was not valuable. 7. The drug reduced the fibrinogen lyses time of rat ex vivo assay and lyses area was increased. 8. Tongdosan reduced fibrinogen lyses time of rat in vitro assay. According to the above mentioned results, Tongdosan increased the blood flow and dropped the blood pressure by the dilation of blood vessel. And the drug presented the antithrombin acivity, inhibited the platelet aggregation.

• The Journal of Internal Korean Medicine
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• v.18 no.1
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• pp.97-113
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• 1997

The present experiment was designed to investigate the effects of Sambutang water extracts on the serum cholesterol levels and the cardiovascular system in the experimental animals. Thus, the changes of blood pressure and heart rate were measured after oral administration. Measurment of Mortality rate was observed for measuring the effect of Sambutang water extract. Sambutang water extract against pulmonary thromboembolism induced by collagen the mixture(0.1 ml/10 g, 2 mg/kg) plus serotonin(5 mg/kg) in mouse. The effect of Sambutang water extract was examined by observing the change of collagen-induced platelet aggregation, coagulation activity, ex vivo and in vitro fibrinolytic activity of euglobulin fraction in rats. The results were summarized as follows. 1. Sambutang decreased the serum cholesterol levels in rats. 2. Sambutang dropped the blood pressure in spontaneous hypertensive rat. 3. The drug increased the auricular blood flow in rabbit. 4. The drug relaxed the artery contraction by pretreated norepinephrine in rat. 5. The drug inhibited the death rate of mouse which was led to thromboembolism by serotonin and collagen. 6. The drug inhibited the platelet aggregation in rat. 7. The drug prolonged the prothrombin time and activated partial thromboplastin time on the test of plasma coagulation factor activity in rat, but was not valuable. 8. The drug increased the antithrombin activity in rat and the fibrinogen lysis time was reduced and lysis area was increased. 9. Sambutang reduced fibrinogen lysis time of rat in vitro assay. According to the above mentioned results. Sambutang increased the blood flow and dropped the blood pressure by the dilation of blood vessel. And the drug presented the antithrombin activity, inhibited the platelet aggregation.