• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.359-363
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• 2011

In this paper, the characteristic of pressures had been analyzed with a series of shapes that are pressure probes used in supersonic wind tunnel. When a performance of supersonic wind tunnel is evaluated, the Mach number is calculated by using the ratio of static pressure in test section wall to total pressure in settling chamber. Also the flow condition can be visualized by schlieren system. However a number of limitations exist to measure pressure of test section due to high speed and boundary layer effect. Therefore a specific pressure probe is needed for evaluating flow condition in test section at a various of positions. In the paper, experiments were conducted in terms of some pitot probes and the results were compared and analyzed.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.5
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• pp.257-264
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• 2016

In this study, experiments for measurements of entrainment rate of fluid mud were carried out using annular flume domestically for the first time. Six entrainment tests using kaolinite sediments were conducted with different initial concentrations of fluid mud. It is shown that sediment settling counteracts the otherwise buoyancy dependent entrainment of fluid mud, and that the settling effect leads to a measurably decreased entrainment rate at higher Richardson numbers in comparison with entrainment of salt water, due to additional dissipation of turbulent kinetic energy in the interfacial layer. Through the comparison with previous other studies, the overall performance of the annular flume, the experimental procedure and the test results in simulating the entrainment of fluid mud are shown to be good enough to verify.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.6
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• pp.911-918
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• 2006

This study was conducted to evaluate the effect of the launder type on settling performance and hydrodynamic behavior within the two certain full-scale sedimentation basins (each flow rate/one basin; $10,000m^3/d$); one is the transverse typed launder(existing basin) and the other is building the finger type launder in combination with the longitudinal baffle. Comparative experimental investigations have been carried out through residual turbidity and particle concentration measurements in each effluent from two basins with the transverse and the finger type launders, respectively. From the experimental results, we could observe that turbidity removal rate in the finger type launder basin (modified basin) is about 30% higher than that in the transverse type launder basin (existing basin). Also, from the measurement of total particle concentration in each effluent, the removal efficiency was improved about 27% within modified basin compared to the existing basin. In order to explain the comparative experimental results and investigate the hydridynamic behavior within each basin in more detail, we conducted computational fluid dynamics (CFD) simulation and verified simulation results with acoustic Doppler velocimetry (ADV) technique. From the CFD simulation, it was investigated that extreme upward flow occurs underneath of the transverse launder. On the other hand, in the case of modified basin, the upward flow, which occurred in the beneath of launder, was much less than that in the existing basins.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.9 no.2
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• pp.233-250
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• 2014

Since 2000, people who lived in the city begin to see returning to farming in a new perspective. People returning to the farming became a trend and therefore, the number of people who are returning to farm are increasing. Because of the concept of take up farming is developing as an idea of establishing a new business, the government agency and the government-related organization are very supportive as the government is interested in the business. The conclusion is below regarding the analysis result In order to receive the analysis of actual proof, we conducted a survey targeting 300 people who returned to farming village in the whole country, excluding Jeju Island from Aug 1st 2013 to Aug 30th 2013. Except uncandidness answers, we used 252 survey results of our sample. Also we used SPSS Wim Ver. 18.0 to draw a conclusion regarding the collected sample. First, regarding of Hypothesis 1 "Personal characteristic will give positive effects in returning to farming village", was partially supportive Second, regarding of Hypothesis 2 "Reason of settling will give positive effects in returning to farming village", was partially supportive Third, regarding of Hypothesis 3 "Geographic characteristics will give positive effects in returning to farming village", was partially supportive Fourth, the effect of social support between the individual characteristic, reason of settling, and geographic characteristics, the result indicated that the social support was partially supportive in farm returners regarding reason of settlement. However, there were no social support effect in returning to farm satisfaction regarding of geographic characteristic. Fifth, after analysing the difference of personal characteristic regarding demographic characteristic, reason of settlement, and geographic characteristic, the result indicated that people who are age 40+, who graduated graduate school lived in metropolitan city, settling to Jeollabuk-do felt higher satisfaction of returning to village than people who are in their 30s, graduated university, lived in city/district, and now settling to Kyung-book and Choong-nam.

• Environmental Engineering Research
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• v.20 no.3
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• pp.298-305
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• 2015

The Standards for Water Works issued by the Korean government prescribed the insertion of inclined plates in a clarifier to enhance the settling of the suspended solids. In this study, in order to verify the role of the inclined plates, two identical laboratory-scale rectangular clarifiers were constructed and eight inclined plates were inserted into one of the clarifiers and inflow from same source was treated in both the clarifiers. Dye tests revealed that only the front three of the seven slots received the inflow at $0.57m^3/m^2{\cdot}h$, which was the highest SOR (surface overflow rate). Three different SORs, with 12 different SS (suspended solid) concentrations at each overflow rate, were fed to both clarifiers. However, the clarifier with the inclined plates failed to show an improved removal rate for the SS. In order to enable the Boycott effect within the slot, it is suggested that each slot created by the inclined plates receives equalized inflow. Moreover, collision of the inflow with the settled sludge at the bottom of the clarifier has to be avoided. These provisions, which can maximize the Boycott effect, should be added to the Standards for Water Works endorsed by Korean government.

• Journal of Arbitration Studies
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• v.11 no.1
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• pp.121-143
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• 2001

Arbitration agreement is an agreement by the parties to submit to arbitration all or certain disputes which have arisen or which may arise between them in respect of defined legal relationship, whether contractual or not. Arbitration has become increasingly popular in settling international and domestic commercial disputes nowadays. The importance of arbitration agreement cannot be overemphasized. It is the most reasonable way to settle commercial disputes. There are two types in arbitration agreement. one is arbitration clause, the other is submission agreement. The arbitration agreement must be made in writing, in addition, other communication instruments shall be considered as effective arbitration agreement if they are properly documented. Over the past few decades, a considerable number of studies have been conducted on the legal property of arbitration agreement in Germany and Japan. Its legal property is aspect of substantial law contract. The basis of arbitration agreement is the principle of party autonomy. The important effect of arbitration agreement is to preclude jurisdiction from national court. The respondent shall raise a plea not later than when submitting his first defense on the merits of the action. As positive effect of arbitration agreement, the court must support the conduct of arbitral proceedings and arbitrator can be appointed upon request of a party.

• Particle and aerosol research
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• v.5 no.1
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• pp.17-27
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• 2009

Particle deposition on a semiconductor wafer larger than 100 mm was studied experimentally and numerically. Particularly the electrostatic effect on particle deposition velocity was investigated. The experimental apparatus consisted of a particle generation system, a particle deposition chamber and a wafer surface scanner. Experimental data of particle deposition velocity were obtained for a semiconductor wafer of 200 mm diameter with the applied voltage of 5,000 V and PSL particles of the sizes between 83 and 495 nm. The experimental data of particle deposition velocity were compared with the present numerical results and the existing experimental data for a 100 mm wafer by Ye et al. (1991) and Opiolka et al. (1994). The present numerical method took into consideration the particle transport mechanisms of convection, Brownian diffusion, gravitational settling and electrostatic attraction in an Eulerian frame of reference. Based on the comparison of the present experimental and numerical results with the existing experimental results the present experimental method for a 200 mm semiconductor wafer was found to be able to present reasonable data.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.4
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• pp.361-367
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• 2016

Pollutants removal and disinfection effect of secondary effluent from final settling tank of sewage treatment plant of W city were investigated in Loop Reactor using ordinary granular activated carbon(GAC) and GAC coated with silver nanoparticles. The results showed that the removal efficiency of $COD_{Mn}$, T-N and T-P using GAC with silver nanoparticles were higher than using the ordinary GAC. The removal efficiency of T-P using GAC with silver nanoparticles is 45.4% and that of T-P using ordinary GAC is 30.9% in the same case of the input amount of 20 g/L of GAC. The total califorms is reduced according to increasing input amount of GAC with silver nanoparticles and ordinary GAC. The disinfection efficiency of total coliforms in case of GAC with silver nanoparticles is much higher than that in case of ordinary GAC. For all experiments using the silver nanoparticles, the total coliforms is under 26 cfu/mL and this shows very excellent disinfection effect.

• Journal of the Korean Applied Science and Technology
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• v.16 no.1
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• pp.95-103
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• 1999

In the separation of toluene/n-heptane mixture by the emulsion type liquid membrane in a batch system, the effect of surfactants on the separation factor and membrane stability were studied over the surfactant concentration ranging from 0.1 to 1.5 wt% at the contact time of 5 and 10 minutes and the settling time 5 and 10 minutes. The surfactants used were triethanol amine lauryl sulfate. The separation factor reached its maximum value at the surfactant concentration of 0.5 wt%. It was found that the percentage of membrane breakup reached its minium values and the separation factor showed its maximum value at the surfactant concentration of 0.5 wt%, which confirmed that efficient separation could be effect when emulsion liquid membrane were stable because of low membrane break up.

• International Journal of Control, Automation, and Systems
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• v.1 no.1
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• pp.1-10
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• 2003

This paper presents a high-precision magnetically levitated (maglev) stage to meet demanding motion specifications in the next-generation precision manufacturing and nanotechnology. Characterization of dynamic behaviors of such a motion stage is a crucial task. In this paper, we address the issues related to the stochastic modeling of the stage including transfer function identification, and noise/disturbance analysis and prediction. Provided are test results on precision dynamics, such as fine settling, effect of optical table oscillation, and position ripple. To deal with the dynamic coupling in the platen, we designed and implemented a multivariable linear quadratic regulator, and performed time-optimal control. We demonstrated how the performance of the current maglev stage can be improved with these analyses and experimental results. The maglev stage operates with positioning noise of 5 nm rms in $\chi$ and y, acceleration capabilities in excess of 2g(20 $m/s^2$), and closed-loop crossover frequency of 100 Hz.