• Journal of Haehwa Medicine
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• v.14 no.1
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• pp.35-42
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• 2005

Objective : The purpose of this research is to examine the effects of Scutellariae Radix(SR) extract on immune cells in ovalbumin(OVA)-induced asthmatic mice. Methods : In vitro, C57BL/6 mice were exposed to OVA for 6 weeks. The mice lungs were taken out, chopped, grinded with collagenase and activated by rIL-3/rIL-5. The lung cells were treated with SR extract and analyzed by a flow cytometer. Results : The population of granulocytes/lymphocytes, CD3e-/CCR3+, CD69+/CD3e+, CD23+/B220+, CD4+ cells in the SR group in vitro decreased and population of CD8+ cells in the 100 and $10{\mu}g/m{\ell}$ SR group in vitro decreased, compared with that of control group. Conclusion : The results of this study support a role for SR as an effective treatment for asthma in its experimental success in significantly decreasing inflammation and asthma reactions.

• Transactions of Materials Processing
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• v.13 no.3
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• pp.253-261
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• 2004

The machining technology for the brittle materials such as ceramics are applied to the fields of MEMS(micro electromechanical system) by the progress of new machining technologies such as Etching, Diamond machining, Micro drilling, EDM(Electro discharge machining), ECDM(Electro discharge machining), USM(Ultrasonic machining), LBM(Laser beam machining), EBM(Electron beam machining). Especially, the USM technology can be applied to the dieletric brittle materials such as silicon, borosilicate glass, silicon nitride, quartz and ceramics with high aspect ratio. The micro machining system with machining force controlled position servo is developed in this paper and the optimized ultrasonic machining algorithm is constructed by the force controlled position servo control. The load cell is adapted in the force measuring and the servo control algorithm, suit for the ultrasonic machining characteristics, is estabilished with using the PID auto-tunning functions at the PMAC system which is generally adapted in the field of robot industries. The precision force signal amplifier is constructed with high precision operational amplifier AD524. The vacuum adsorption chuck which is made of titanum and internal flow line is engraved, is used in the workpiece fixing. The mahining results by USM shows that there are some deviation between the force command and the actual machining force that the servo control algorithm should be applied in the machining procedures. Therefore, the constant force controlled position servo system is developed for the micro USM system and by the examination machining process in USM, the stable USM system is realized by tracking the average value of machining force.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.4
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• pp.559-568
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• 2013

Increased worldwide concerns about fossil fuel costs and effects on the environment lead many governments and scientific societies to consider the hydrogen as the fuel of the future. Many researches have been made to assess the suitability of using the hydrogen gas as fuel for internal combustion engines and gas turbines; this suitability was assessed from several viewpoints including the combustion characteristics, the fuel production and storage and also the thermodynamic cycle changes with the application of hydrogen instead of ordinary fossil fuels. This paper introduces the basic environmental differences happening when changing the fuel of a marine gas turbine from marine diesel fuel to gaseous hydrogen for the same power output. Environmentally, the hydrogen is the best when the $CO_2$ emissions are considered, zero carbon dioxide emissions can be theoretically attained. But when the $NO_x$ emissions are considered, the hydrogen is not the best based on the unit heat input. The hydrogen produces 270% more $NO_x$ than the diesel case without any control measures. This is primarily due to the increased air flow rate bringing more nitrogen into the combustion chamber and the increased combustion temperature (10% more than the diesel case). Efficient and of course expensive $NO_x$ control measures are a must to control these emissions levels.

• Journal of the Korean Society of Food Culture
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• v.10 no.1
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• pp.35-44
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• 1995

A hazard analysis which included watching operations, measuring temperatures of foods throughout preparation and display, and sampling and testing for microorganisms of total plate counts and coliform bacteria was conducted in various phases of product flow of Korean soups (Galbitang, Sullungtang, Jangkuk) prepared at Korean restaurants. Cooked foods were sometimes held at room temperature long enough to permit multiplication of bacteria that might have been present. This was confirmed by the finding of large numbers of aerobic mesophilic colonies ($10^6$) in samples of such foods after handling and holding for several hours before served. These bacteria decreased down to $10^1{\sim}10^2$ while the contaminated Tang were served. And internal temperature of Tang served was approximately $70^{\circ}C$. Critical control points identified were, pre-preparation, handling after cooking and holding on display. Guidelines were suggested for effective quality control of Tang (Korean soups) production. Handlers of these foods need to be informed of the hazards and appropriate preventive measures.

• Journal of Drive and Control
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• v.13 no.3
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• pp.15-23
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• 2016

The direct-drive servo valve(DDV) is a kind of one-stage valve because the main spool valve is directly driven by the dc motor. Since the DDV structure is simple, it is less expensive, more reliable, and offers a reduced internal leakage and a reduced sensitivity to fluid contamination. The control system of the DDV is highly nonlinear due to a current limiter, a voltage limiter, and the flow-force effect on the spool motion. The shape of the step response of the DDV-control system varies considerably according to the magnitudes of the step input and the load pressure. The system-design requirements mean that the overshoots should be less than 20%, and the errors at 0.02s should be less than 2%, regardless of the reference-step input sizes of 1V and 5V and the load-pressure magnitudes of 0MPa and 20.7MPa. To satisfy the system-design requirements, the PID-controller parameters of $K_c$, $T_i$ and $T_d$, and the derivative-feedback gain of $K_{der}$ are designed using the root locus and manual tuning.

• Journal of Korean Traditional Oncology
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• v.20 no.2
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• pp.13-21
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• 2015

Objective : The objective of this study was to investigate the experimental efficacy of anti-tumor activity of the complexed herbal formula, Onbaekwon (OBW), which was derived from the literature of Traditional Korean Medicine, Dongeuibogam. Methods : Nine Cancer cell lines, LoVo, MCF-7, HepG2, AGS, A549, NCI-H69, HL-60, Sarcoma 180, LL/2, were prepared and the cytotoxicity was assessed by 3-(4,5-dimethylthiazol-2yl)-2,5-dephenyl tetrazolium bromide (MTT) assay. Four of them, NCI-H69, HL-60, Sarcoma 180, and LL/2, showed strong cytotoxic activities and they were additionally undergone flow cytometry to find out their effects on apoptosis. ICR male mice were implanted with Sarcoma 180 intraperitoneally and divided into 8 species for each group. Control group was treated with normal saline, positive control group was treated with cyclophosphamide 8mg/kg, and experimental group was treated with OBW 1 g/kg. Results : Among 9 cancer cell lines, NCI-H69, HL-60, Sarcoma 180, and LL/2, expressed less than 0.10 mg/ml of $IC_{50}$ under 0.1~1mg/ml of OBW. NCI-H69, HL-60, Sarcoma 180, and LL/2, showed dose-dependent efficacy of apoptosis. When Sarcoma 180 cancer cell was implanted in ICR male mice and treated with the OBW, they prolonged the median overall survival for 0.8 days, from 17.5 to 18.3. Conclusion : OBW showed strong cytotoxicity to some cancer cells, which are NCI-H69, HL-60, Sarcoma 180, and LL/2, and its apoptotic activity was dose-dependent. OBW prolonged the median survival of mice implanted with Sarcoma 180. Further researches would be expected to support the efficacy of OBW.

• The Journal of the Korea Contents Association
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• v.8 no.4
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• pp.117-129
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• 2008

This analysis is intended to approach a computer game in the context of cultural-study theories. The semiotics can be applied to various area, and it is assumed to also applied to computer games. In semiotical background we tried to analyze the mythology of Starcraft mainly by using Propp's narratives theory and Brathes' mythologies theory. In the narratives of Starcraft, we fouind some simplified functions which penetrate the internal structure. And while most of the games having paradigmatic flow in narratives, Starcraft has syntagmatic flow mainly because of the function of network. With these conditions, we could find some mythologies in Starcraft : (1) naturalization of discipline and control, (2) time and space as resources, (3) deprivation of values of object.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.4
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• pp.498-505
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• 2008

Many researches have been studied on in-cylinder flow as one of dominant effects for an engine combustion. The combustion phenomena of reciprocating engine is one of the most important processes affecting performance and emissions. One effective way to improve the engine combustion is to control the motion of the charge inside a cylinder by means of optimum induction system design. It is believed that the tumble and swirl motion generated during intake breaks down into small-scale turbulence in the compression stroke of the cycle. However, the exact nature of their relationship is not well known. To know this relationship definitely, this paper describes analytical results of the tumble motion, swirl motion, turbulence intensity, turbulence inside the cylinder of marine engine. 3-D computation has been performed by using STAR-CD solver and es-ice.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.2070-2075
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• 2004

Performance of a solid oxide fuel cell (SOFC) can be enhanced by converting thermal energy of its high temperature exhaust gas to mechanical power using a micro gas turbine (MGT). A MGT plays also an important role to pressurize and warm up inlet gas streams of the SOFC. In this study, the influence of performance characteristics of the tubular SOFC on the hybrid power system is discussed. For this purpose, detailed heat and mass transfer with reforming and electrochemical reactions in the SOFC are mathematically modeled, and their results are reflected to the performance analysis. The analysis target is 220kWe SOFC/MGT hybrid system based on the tubular SOFC developed by Siemens-Westinghouse. Special attention is paid to the ohmic losses in the tubular SOFC counting not only current flow in radial direction, but also current flow in circumferential direction through the anode and cathode.

• Corrosion Science and Technology
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• v.18 no.4
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• pp.148-153
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• 2019

Pure nickel with a thickness of 1 mm was plated on type 304 stainless steels and low alloy steels (JIS G3131 SPHC) by electrolytic plating method in a circulating plating bath. Plating performance, mechanical properties, and surface characteristics were evaluated in terms of pretreatment process, anode material, pH, current density, and flow rate of the plating solution. Addition of hydrochloric acid during pre-treatment process improved the adhesion performance of plating. To improve plating efficiency, it is desirable to use S-nickel rather than electrolytic nickel. The use of S-nickel was also confirmed to be desirable for maintaining the pH and concentration of the plated solution. The defect of the plating using S-nickel anode produced pit on the surface. However, it is believed that proper control can be obtained by increasing the flow rate. Internal stress and hardness values of electrolytic nickel plating according to current density need to be carried out with further studies.