• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.207-210
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• 2008

In this study, one type of ramjet intake were designed for the flight condition of Mach number 4 and numerical analysis was performed. In order to widen the flight envelope range (Mach number $2{\sim}6$), movable intake concept was applied. The central body was designed so that the capture area ratio which is one of most important factors of ramjet intake design could be adjusted. And various types of cowl and movable insert part of shell were designed in order to control throat area which could increase total pressure recovery. The numerical results showed that the designed ramjet intake could be applied in various flights Mach number.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.171-178
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• 2005

It is unavoidable to be formed slopes under special circumstance of Korea where 70% of the whole area are composed of mountains when civil engineering projects such as roads, site developments are increased with industrial development and horizontal expansions of urban area. Moreover, stability of the slopes become one of quite important issues under special meteorological characteristics that over two-thirds of annual average rainfall are concentrated in summer season and the localized torrential downpour are getting more frequent recently. Resulting in these circumstances, partial slope failures by debris flow of the high water content soils are occurred frequently in cutting soil slopes. In this case of debris flow slope failure, slope declination method are selected for their stable recovery because it is impossible to recover entirely by existing recovery methods. Seeding or special grass planting methods are followed separately without exception. The method by which entire recover with bigger stability ratio would be possible and grass planting work would be done simultaneously is developed. In this study, the results of the tests including a real construction history in a failed slope using developed method are described

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.3
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• pp.49-59
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• 2008

In this study, the design method of a 155 mm Solid Fuel Ramjet projectile is proposed and a flight performance analysis program through mathematical modelling is developed. Through flight performance analysis, ramjet performance during flight, which is comprised of thrust, specific impulse, pressure recovery ratio, location of shock waves, and magnitude of drag, was predicted. The results show that compared to Rocket Assisted Projectile(RAP), the range was increased by 90 %. Furthermore, how variations in nozzle exit area ratio and the intake area cause variations in range was observed. This research on modeling and simulation methodology will provide useful data for future development of solid fuel ramjet projectiles.

• Journal of Biosystems Engineering
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• v.25 no.1
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• pp.33-38
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• 2000

This study was performed to investigate airtight storage characteristics of rough rice using airtight flexible pve container. A storage test of rough rice of 4 tonnes was carried out to determine the changes of gas composition of air in the container, grain moisture content, air temperature and relative humidity , the presence of insects ,germination rate, crack ratio , fat acidity , 1000-kernel weight, and brown rice recovery over storage period of 5 months in Suwon. Concentration of oxygen was decreased from 20% to 16% and carbon dioxide was increased of from 0.03% to 1.6%. The grain moisture content was decreased from 14.4%(w.b) to 14.1%(w.b) for 5 months storage period . Insect population levels were low but these increased after 5 months storage. Most of insects were dead, Fat acidity increased from 7.5(mg KOH/100g) to 10.2(mg KOH/100g). Other storage factors such as germination rate, brown rice recovery and 1000-kernel , and 1000-kernel weight slightly decreased and crack ratio was slightly increased. Qualities of rough rice during 5 months storage period under hemetic air conditions were maintained fairly good considering the above changes of quality factors during storage.

• Journal of Veterinary Clinics
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• v.19 no.2
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• pp.115-120
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• 2002

To clarify the therapeutic effect of aquapuncture therapy on bovine foot rot, the experimental cattle were divided into control (conventional treatment), aquapuncture and combined treatment groups. Each group was composed of 6 Holstein cows with bovine foot rot. In the present study, the change in grade of lameness, total leukocyte counts, N/L. ratio, mean recovery rates (days) and histopathological changes of interdigital tissue before and after treatment were evaluated. The grade of lameness was decreased by treatment in each group, with the decreasing in order of combined > aquapuncture > control group. In change of total peripheral blood leukocyte counts, the tendency of decrease was found. Significances were detected on 9th day (P < 0.05) in control, on 6th day (P < 0.01) in aquapuncture group, and on 3rd (P < 0.05) and 6th day (P < 0.05) in combined group, respectively. In addition, significances were detected on 3rd and 6th day in aquapuncture, and on 3rd day in combined group by comparison with that of control, respectively. N/L ratio was decreased by therapy in each group with the decreasing in order of combined > aquapuncture ) control group. Significances were detected on 6th day (P < 0.01) between aquapuncture and combined groups. The mean recovery rates(days) were rapid with the decreasing in order of combined > acuapuncture > control group. In histopathological findings of interdigital tissue, the findings of inflammation and hemorrhage were not observed after treatment in each group. In conclusion, it was thought that aquapuncture and combined therapy was very effective on treatment of bovine foot rot.

• Journal of Chest Surgery
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• v.30 no.1
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• pp.11-16
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• 1997

The Increasing use of coronary perfusates for the protection of the human heart during ischemic cardiac arrest has placed great emphasis on the need for a rational and safe formulation. For the purpose of this study isolated rat hearts were connected to retrograde nonworking perfusion system proposed by Langendorff, and then perfused for 20 minutes by coronary infusates of magnesium concentration of 1.66 m Mol per liter(group A, n: 10) or 15mMo1 per liter(group B, n: 10). After 20 minutes perfusion, cold cardioplegic solution (modified St. Thomas'Hospital solution) was infused for 2 minutes, and prepared within 4$^{\circ}C$ Krebs-Henseleit solution. Finally, 20 minutes of cononay reprsfuslon was reestablished after I hour of cold ischemic cardiac arrest. Hemodynamic parameters (heart rate, left ventricular pressure, $\pm$ dp/dt max. and coronany flow) and enzymes assay (creatine phosphokinase, lactic dehydrogenase and flutamic oxaloacetic transaminase) were performed each other at whic rat heart was perfused for 20 minutes and reperfused for 20 minutes thereafter. There were significant differences in the recovery rate of heart rate, systolic left ventricular pressure, + dp/dt max, and coronary flow and reperfusion-perfusion ratio of creatine phosphokinase(P < 0.05). But, there were no signicant differences in the recovery rate of dp/dt max, and reperfunion-perfusion ratio of lactic dehydrogenase and glutamic oxaloacetic acid (P > 0.05).

• Journal of Korean Society on Water Environment
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• v.22 no.2
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• pp.288-293
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• 2006

Basic investigations have been carried out for the solvent extraction of silver contained in the waste photographic fixing solution using D2EHPA as an extractant. Extraction experiments were conducted using artificial waste solution which was made by dissolving $AgNO_3$ in distilled water along with actual waste fixing solution. For artificial waste solution, the extraction of silver was found to occur very rapidly at the initial stage of extraction. In addition, more silver was extracted as the volumetric ratio between aqueous phase and organic phase was decreased. The volumetric ratio of organic extractant to diluent was also taken as an influential variable and the extracted amount of silver was observed to decrease with temperature. The characteristics of silver extraction for actual fixing solution was generally similar to that for artificial waste solution. Regarding the kinetic analysis, the extraction of silver contained in the actual solution was observed to follow a first order reaction.

• Textile Coloration and Finishing
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• v.5 no.4
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• pp.79-91
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• 1993

The purpose of this study is to prepare the newer, more comfortable of urea-formaldehyde resin finished fabrics. The methods of this study are by making examinations and comparisons the relations between the thickness, fabrics counts, weight, moisture regain and crease recovery of cotton and viscose rayon fabrics caused by condition of urea-formaldehyde resin finishing and warm retaining ability and warm-cool sense. The analytic results of thermal character in state of fabrics material finished with urea-formaldehyde are as follows: 1. The warm retaining ability has no correlation with mixing ratio of resin but the increase of the warm retaining ability has correlation with the increase of concentration of urea-formaldehyde resin. 2. The result pf multiple regression analysis for effect of physical property according to the concentration of resin to the warm retaining ability revealed as below. As the weight, thickness and density increase and moisture regain decreases, the warm retaining ability increases. 3. The qmax value has no correlation with mixing ratio of resin but the increase of the qmax value has correlation with the increase of resin concentration. In the end, the effect of it promotes cool sense. 4. The result of multiple regression analysis for effect of physical property according to the concentration of resin to the qmax value revealed as below. As he weight and thickness increase, the qmax value decrease. But, as the density and crease recovery increase, the qmax value increase.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2004.05a
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• pp.171-176
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• 2004

Heat regenerator attached in small-scale regenerative radiant tube burner was designed using the theoretical computation code and was confirmed the performance of waste heat recovery ratio. From the computation, when ceramic ball of 4-5kg was used, temperature efficiency and available waste heat recovery ratio were predicted 80% and 70%, respectively. Similar efficiencies were obtained from the experiments using LPG. However, since exhaust gas temperature entered into regenerator was below 85$0^{\circ}C$ which was much lower than that we expected, preheat air temperature was lowered below 80$0^{\circ}C$.

• The KSFM Journal of Fluid Machinery
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• v.18 no.3
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• pp.60-65
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• 2015

This paper deals with performance characteristics and efficiencies of Pelton turbine can be applied as one of ERDs (Energy Recovery Devices) of PRO (Pressure Retarded Osmosis) system for desalination. The objective of this study is experimentally estimating the performance of micro-scale Pelton turbine for PRO pilot plant. Especially the performance characteristics with variations of jet nozzle diameter of Pelton turbine are discussed in detail. In order to do this, lab scale test rig of Pelton turbine was made for performance test, which includes water tank, Pelton wheel with buckets, jet nozzle and torque brake and so on. The parameter effects related on Pelton turbine's efficiency were investigated and discussed on the influence of the variations of load and speed ratio.