• Journal of Environmental Science International
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• v.14 no.1
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• pp.61-69
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• 2005

Adsorption characteristics of toluene vapor, which is one of important source of volatile organic compounds (VOCs), by activated carbon were investigated using a fixed bed adsorption column. The operating parameters such as breakthrough curve, adsorption capacity, mass transfer zone (MTZ), and length of unused bed (LUB) were studied. The experimental results showed that the breakthrough time decreased with increasing inlet toluene concentration and gas flow rate. MTZ and LUB increased with the increase of inlet concentration, gas flow rate, and particle size of activated carbon. The adsorption capacity increased with the increase of inlet toluene concentration, while it decreased with increasing particle size. However, it was kept at constant value regardless of the increase of gas flow rate. Adsorption isotherm of toluene vapor could be represented by the Freundlich adsorption equation fairly well. From the adsorption experiments using some VOC gases such as toluene, xylene, butyl acetate. butanol and acetone, it was also found that the adsorption capacity was higher in the case of gas with higher boiling point and lower vapor pressure.

• Korean Chemical Engineering Research
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• v.46 no.6
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• pp.1057-1062
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• 2008

To overcome disadvantages of conventional two interconnected fluidized beds system, a novel two-interconnected fluidized bed process has been adopted to 3kW chemical-looping combustor. This system has two bubbling beds, solid injection nozzles, solid conveying lines, and downcomers. In this study, effects of operating variables such as gas velocity through the solid injection nozzle, fluidizing velocity, solid height, geometry of solid intake hole, bed temperature on solid circulation rate have been investigated in a 3kW chemical-looping combustor. The solid circulation rate increased as the solid height and the opening area of solid intake holes increased. The effect of the fluidizing velocity and the bed temperature were negligible. Moreover, long-term operation of continuous solid circulation up to 50 hours has been performed to check feasibility of stable operation. The pressure drop profiles in the bubbling beds and the downcomers were maintained steadily and solid circulation was smooth and stable.

• Journal of Korea Water Resources Association
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• v.55 no.1
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• pp.23-32
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• 2022

This paper performs two-dimensional numerical simulation of surface water-groundwater coupled flow and solute transport to investigate the effect of the hyporheic exchange at the sediment-water interface (SWI) on surface solute transport. For the impermeable bed case in the absence of hyporheic flow, the trapping effect of flow recirculation associated with the ripple bed controls the shape of breakthrough curves (BTCs). However, the permeable bed case with hyporheic flow stimulates the extended tailing of the BTCs more significantly due to the elevated concentration of the BTC tailing resulting from slow hyporheic velocity. Also, the increased bottom pressure at the SWI with an increase in surface velocity shortens the BTC tailing because of increasing hyporheic velocity. These results infer that hyporhiec flow is critically important in predicting solute residence times in surface water.

• Journal of Acupuncture Research
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• v.23 no.6
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• pp.165-176
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• 2006

Objectives : Aim of this study was to investigate the antihypertensive effect of Korean Hwa-Acupuncture in hypertensive patients. Methods: We measured the blood pressure of 14 patients who were admitted in the Oriental Medical Clinic of Balance & Harmony Korean Acupuncture Association from 25th March 2006 to 21th July 2006. Eligible participants had systolic blood pressure ${\geq}120mmHg$ diastolic blood $pressure{\geq}80mmHg$. Blood pressure and pulse rate measurements were after the patient had been bed rest for at least 30 min. 10 times of Hwa-Acupuncture treatment over 3 weeks period were performed in the patiants. To evaluate the effect of the Hwa-Acupuncture, the blood pressure, pulse rate were measured 2 times before and after each acupuncture treatment for total of 10 times. Results : After 3 weeks, there were significant decreased in the systolic blood pressure(P<0.0297) and significant decreased in diastolic blood pressure(P<0.0223) treated by Hwa-Acupuncture 10 times but pulse rate was failed to decreased. The effects of Hwa-Acupuncture by measuring time on blood pressure were as follows : systolic blood pressure were deceased significantly from 1st to 10th visit (P<0.0207) but diastolic blood pressure and pulse rate was not decreased significantly. Conclusion : The results suggest that Hwa-Acupuncture is effective in decreasing the systolic blood pressure.

• Korean Journal of Acupuncture
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• v.24 no.1
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• pp.27-41
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• 2007

Objectives : The aim of this study was to investigate the antihypertensive effect of Korean Gogoon Acupuncture in hypertensive patients. Methods : We measured the blood pressure of 17 patients who were admitted in the Oriental Medical Clinic of Gogoon Institute from 14th April 2006 to 29th August 2006. Eligible participants had systolic blood pressure ${\geq}120$ mmHg or diastolic blood $pressure{\geq}80$ mmHg. Blood pressure and pulse rate measurements were after the patient had been in bed rest for at least 30 min. Six sessions of Gogoon Acupuncture treatment over three weeks were performed in the patients. Blood pressure and pulse rate were measured twice before and after each acupuncture treatment. Results : After 3 weeks, there were significant decreases in systolic blood pressure(p=0.0028), diastolic blood pressure (p=0.0111) and pulse rate (p=0.0150). The effects of Gogoon Acupuncture by measuring time on blood pressure were as follows : In a systolic blood pressure (p<.0001) and diastolic blood pressure (p=0.0028) was gradually deceased significantly from 1st to 6th but pulse rate was not significantly decreased. Conclusions : Controlled trials investigating the efficacy of Gogoon acupuncture for lowering blood pressure are warranted.

• Journal of Adhesion and Interface
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• v.22 no.3
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• pp.85-90
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• 2021

Generally, the tensile strength of carbon fiber reinforced composite (CFRP) should be determined to produce this material. The tensile strength was performed based on ASTM D3039, and this test could cause the error by specimens and human. In this research, the CFRP tensile test was performed with different thickness of specimens and tap, adhesive for attaching tap, and pressure of jig to hold the specimens, while the test was performed based on ASTM D3039. The tensile stress and modulus exhibited differently with different specimen thicknesses, and the 1~1.5 mm thickness of the specimen was optimized. In the case of 0.28 MPa jig pressure, the slip or fracture at the clamping area of the specimen has not occurred, and specimens were fractured to the center section of the specimen. The adhesive to attach jig on specimen should be used to exhibit high adhesive stress. Experimental parameters could cause errors. It is expected to achieve an accurate tensile property evaluation of composite materials via improvements in adhesives, tabs, and jigs.

• Journal of Korea Society of Industrial Information Systems
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• v.25 no.6
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• pp.47-54
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• 2020

The acupressure is a treatment that applies pressure to certain parts of the body and has been mainly used for pain relief in the field of oriental medicine. However, the treatment effect is often different depending on the practitioner's ability, experience, and physical strength, so standardized acupressure is needed. In this regard, the equipment is being released, but this is mainly a rolling massage method, which reduces energy concentration and poses a risk of injury. Therefore, in this study, a device that provides vertical acupressure based on variable bogie (wheel truck) was implemented. As a result of experimenting with load and body pressure distribution and desirability to validate the device's bearing pressure, the acupressure rod held up to 150kg, the body pressure ratio was measured lower than the body pressure ratio of the comparison item in section 0%

• Polymer(Korea)
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• v.32 no.4
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• pp.328-333
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• 2008

The osmotic delivery systems are based on osmosis. The transverse diffusion of water through a porous membrane from a medium with a low osmotic pressure to a medium with a high osmotic pressure. Nifedipine tablet dosage forms of Procardia $XL^{(R)}$(Pfizer) and $Adalat^{(R)}$(Bayer) are commercialized systems of this type that push-pull osmotic tablet operates successfully in delivering water-insoluble drugs. We prepared osmotic pellet system by fluidized bed coating method, and model-drug used nifedipine. The osmotic pellet system was composed of the core material. the swelling and osmotic pressure layer, the drug coating layer, and the porous membrane. This work is performed to investigate the effect of different factors, such as composition and thickness of membrane. The osmotic pellet has been successfully prepared by fluidized bed coating technology. The drug release behavior depended on the increase of CA ratio and thickness in porous membrane. The morphology of the osmotic pellet before and after the dissolution test were observed by SEM. In conclusion, we found that the drug release of osmotic pellet depended on the composition and coating thickness of porous membrane.

• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.3
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• pp.87-94
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• 2000

To recommend adequate covering materials and shapes of rice nursery bed for mechanical transplanting rice seedling, measuring of microclimate inside the rice nursery protected by polyethylene tunnel type, polyester tunnel type, and polyester flat type was compared to that outside the nursery. The vapor pressure deficit inside the polyester tunnel and polyethylene tunnel was higher than that outside the tunnel during daytime on a sunny day. During daytime on cloudy with rain day, the vapor pressure deficit inside polyester tunnel was higher than that in polyethylene tunnel or outside the nursery tunnel. The heat fluxes in the rice nursery tunnel during daytime flowed more to the soil than to the outside tunnel. Amounts of soil heat fluxes in polyethylene tunnel were higher than in polyester flat and polyester tunnel. The vertical profile of air temperature inside the nursery tunnel came to inversion during daytime and was lapse during nighttime regardless weather condition. The maximum temperature inside the nursery tunnel were 47.2$^{\circ}C$ in polyethylene tunnel and 37.$0^{\circ}C$ in polyester tunnel which was 21.1$^{\circ}C$ and 10.9$^{\circ}C$ higher than outside the tunnels respectively on sunny day. On cloudy with rain day, the temperature inside nursery tunnel was higher 8.4$^{\circ}C$ and 4.$0^{\circ}C$ polyethylene and polyester tunnel respectively then outside. Daily temperature changes became larger in the polyethylene tunnel, polyester tunnel, and outside the nursery tunnel in order. The rice seedling growth in polyester tunnel was better than the other nursery beds.

• Korean Chemical Engineering Research
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• v.46 no.2
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• pp.414-422
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• 2008

Adsorption experiments for $H_2$, $CH_4$, CO, $CO_2$ on activated carbon and zeolite 5A were performed by static volumetric method. A 4-bed pressure swing adsorption (PSA) process was to study separation of hydrogen from multi-component mixture gases ($H_2$ 72.2%, $CH_4$ 4.06%, CO 2.03%, $CO_2$ 21.6%). Dual-site langmuir (DSL) isotherm showed good or fair agreement with the experimental results. The optimum height of activated carbon layer was 55 cm with breakthrough results on the packing ratio of activated carbon to zeolite 5A. In PSA process, the effects of the process parameters such as total cycle time ($T_c$), ${\Delta}P$ at the provide purge step and adsorption pressure on the PSA performance were studied experimentally and theoretically.