• Transactions of Materials Processing
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• v.15 no.1 s.82
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• pp.76-81
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• 2006

In this study, warpage characteristics of mobile phone cover through injection molding process were investigated using design of experiments in injection molding process. Warpage in plastic injection molding has a significant effect on quality of product. Effects of injection time, packing pressure, packing time, mold temperature and melt temperature on the warpage of mobile phone cover were considered by numerical analysis and experiment with Taguchi method. The degree of warpage for the injection molded part was measured by using three dimensional coordinate measurement machine. It was shown that temperature control factor has more significant effect on the warpage of mobile phone cover than pressure control factor.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.183-186
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• 2007

The injection molding process has high accuracy and good reproducibility that are essential for mass production at low cost. Conventional molding processes typically use the water-based mold heating and air cooling methods. However, in the nano injection molding processes, this semi-active mold temperature control results in the several defects such as air-flow mark, non-fill, sticking and tearing, etc. Therefore, in order to control temperature of the molds actively and improve the quality of the molded products, the novel nano injection molding system, which uses active heating and cooling method, has been introduced. By using the Peltier devices, the temperature of locally adiabatic molds can be controlled dramatically and the quality of the molded patterns can be improved.

• Transactions of Materials Processing
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• v.17 no.5
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• pp.337-342
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• 2008

The injection molding process has high accuracy and good reproducibility that are essential for mass production at low cost. Conventional molding processes typically use the water-based mold heating and air cooling methods. However, in the nano injection molding processes, this semi-active mold temperature control results in the several defects such as air-flow mark, non-fill, sticking and tearing, etc. In order to actively control temperature of the molds and effectively improve the quality of the molded products, the novel nano injection molding system, which uses active heating and cooling method, has been introduced. By using the Peltier devices, the temperature of locally adiabatic molds can be controlled dramatically and the quality of the molded patterns can be improved.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.6
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• pp.224-237
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• 1995

An ECU(Electronic Control Unit) with 16 bit microcomputer has been developed. This system includes hardware and software for more precise control on fuel injection, ignition timing, and idle speed. This control system employs an air flow sensor of the hot wire type, a direct ignition system, an idle speed control system using a solenoid valve, and a crank angle sensor. Especially, the crank angle sensor provides two separate signals: One is the position signal(POS) which indicates 180 degree pulses per revolution, and the other is the reference signla(REF) that represents each cylinder individually. The conventional engine control system requires at least two engine revolutions in order to identify the cylinder number. However, the developed engine control system can recognize the cylinder number within a quarter of an engine revolution. Therfore, the developed engine control system has been able to control fuel injection and ignition timing more quickly and accurately, Furthermore, the number of misfire reduces during the cold start.

• Herbal Formula Science
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• v.12 no.1
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• pp.195-208
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• 2004

Objective: This study was conducted to investigate the effects of Aconiti Tuber on the plasma IL-6 and $TNF-{\alpha}$ level in mice stimulated by intracerebroventricular(I.C.V.) Injection of Lipopolysaccharide(LPS). Method: 6 mice were assigned to each of the normal group, the control group, and the experimental group. In the normal group only saline was administered intragastrically, and in the control group LPS was injected intracerebro-ventricularly 1 hr after intragastric administration of saline. In the experimental groups (Aconiti Tuber 0.5g/kg, Aconiti Tuber 1.0g/kg, Aconiti Tuber 3.0g/kg) each sample was administered intragastrically to mice 1 hr prior to the stimulation by LPS I.C.V. Injection. To measure the plasma IL-6 and $TNF-{\alpha}$ level of mice, their blood samples were collected from retro-orbital plexus, immediately centrifuged at $4^{\circ}C$, and plasma was removed and stored frozen at $-83^{\circ}C$ for later determination of plasma IL-6 and $TNF-{\alpha}$. Result : 1. LPS I.C.V. Injection increased plasma IL-6 level significantly in a dose-dependent manner compared with normal group(P<0.01). The plasma IL-6 concentration reached a significant maximal level about 1 hr after LPS I.C.V. Injection(P<0.001). LPS I.C.V. Injection increased plasma $TNF-{\alpha}$ level significantly in a dose-dependent manner(P<0.05). The plasma $TNF-{\alpha}$ concentration reached a significant maximal level about 1 hr after LPS I.C.V. Injection(P<0.001). 2. Sample A group to which Aconiti Tuber(0.5g/kg) was administered intragastrically 1 hr prior to the stimulation by LPS I.C.V. Injection showed insignificant lower plasma IL-6 level in 1 hr than control group(P<0.0635), and sample B group (Aconiti Tuber 1.0g/kg) showed significant lower plasma IL-6 level in 1 hr than control group(P〈0.05), and sample C group (Aconiti Tuber 3.0g/kg) showed significant lower IL-6 plasma level in 1 hr than control group(P<0.01). 3. sample A group to which Aconiti Tuber(0.5g/kg) was administered intragastrically 1 hr prior to the stimulation by LPS I.C.V. Injection showed insignificant lower plasma $TNF-{\alpha}$ level in 1 hr than control group(P>0.05), and Both sample B(1.0g/kg) and sample C(3.0g/kg) groups showed significant lower $TNF-{\alpha}$ plasma level in 1 hr than control group(P<0.01). These data revealed that Aconiti Tuber might have the anti inflammatory effect by reducing the plasma IL-6 and $TNF-{\alpha}$ level in a dose dependent manner in mice LPS I.C.V. Injection.

• Transactions of The Korea Fluid Power Systems Society
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• v.5 no.4
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• pp.26-31
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• 2008

This paper deals with the issue of position tracking control of a clamp-cylinder for injection moulding machine with electric-hydrostatic drives. A fixed displacement pump is utilized in combination with AC motor in order to directly control a clamp-cylinder. A clamp-cylinder may be required to operate under a variety of operating conditions. Therefore, robust control performance is important in position tracking control applications. In order to accommodate mismatches between the real plant and the model used for controller design, discrete-time sliding mode control is developed by combining a velocity feedforward loop. From tracking control experiments, it is shown that significant reduction in position tracking error is achieved through the use of sliding mode control.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.119-122
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• 2002

In general, Liquid Injection Thrust Vector Control(LITVC) is accomplished by injecting a liquid into the supersonic exhaust flow through holes in the wall of the propulsion nozzle. This injection flow field is highly complicated and detailed flow physics associated with the secondary flow injection should be known far the practical design and use of the LITVC system. The present study aims at understanding the LTTVC flow field and obtaining fundamental design parameters for LITVC. The experimentations were performed in a supersonic blow-down wind tunnel. Compressed, dry air was used for both the main exhaust and injection flows but the pressures of these two flows were controlled independently. The location of the injection holes was changed and the pressures of the two streams were also changed between 2.0 and 15.0 bar. The effectiveness of LITVC was discussed in details using the results of the pressure measurements and flow visualizations

• Journal of The Korean Dental Society of Anesthesiology
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• v.6 no.2 s.11
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• pp.98-102
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• 2006

The purpose of this study was to evaluate the difference on pain intensity and discomfort between pressure-controlled injection system and conventional syringe injection technique from the patients undergoing oral and maxillofacial surgery. In a prospective, randomized, case-controlled study, 60 patients were divided into two groups (n=30 in each). In experimental group, pressure-controlled injection system was applied. In control group, conventional syringe injection system was applied. Pain rating score (PRS) and visual analogue scale (VAS) were assessed. The average of VAS in experimental group ($16.67{\pm}15.07$) was smaller than that of control group ($25.63{\pm}22.21$), though there were no significant differences (P=0.072). In PRS, fifteen patients (50.0%) of experimental group answered that they experienced mild pain. However sixteen patients (53.3%) of control group answered that they experienced intermediate pain. From the results, pressure-controlled injection system may be an effective method to reduce pain during the dental local anesthetic procedure.

• Korean Journal of Plant Resources
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• v.20 no.6
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• pp.548-552
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• 2007

This research is the basic research to develop new anti-inflammatory medicine by feeding Scutellariae Radix extract to lipopolysaccharide(LPS) exposed rats, and analyzed it's effect on inflammatory response by LPS derivation. As a result, Plasma interleukin-$1\beta(IL-1\beta)$ and Plasma interleukin-6(IL-6) concentration showed the highest point at 5h after LPS injection, and in this time, the concentration of $IL-1\beta$ and IL-6 in the Scutellariae Radix extract groups at 200mg/kg and 300mg/kg showed lower values than that of control group. Plasma tumor necrosis $factor-\alpha(TNF-\alpha)$ concentration after LPS injection showed the highest point at 2h and showed similar level till at 5h. $TNF-\alpha$ concentration at 2h after LPS injection showed the low value only in the Scutellariae Radix extract 300mg/kg group compared to others, and in 5h, the all Scutellariae Radix extract groups showed lower value than that of the control group. Plasma interleukin-10(IL-10) concentration increased at 2h after LPS injection and reached the highest at 5h. After LPS injection the IL-10 concentration at 2h, the Scutellariae Radix extract injection group at 300mg/kg showed higher value than that of the others, and in 5h after LPS injection, Scutellariae Radix extract 200mg and 300mg groups showed higher value than the control group. Concluding from the above results, in inflammatory response by LPS derivation, the Scutellariae Radix gives positive effect.

• Journal of ILASS-Korea
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• v.16 no.3
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• pp.134-139
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• 2011

Recent research has focused on engine combustion technology as well as application of after-treatment in order to comply with emission regulation. However, it is much more efficient way to control emissions from engine itself and furthermore research on engine control will provide the direction of after-treatment technology in future. Furthermore, emission standard regulation for passenger diesel vehicles has been stringent compared to others and nano-particles will be included in EURO6 regulation in Europe and similar emission standard will be introduced in Korea. A 3.0 liter high speed diesel engine equipped with by CRDI system of 160MPa injection pressure, and an intake/exhaust system of V type 6 cylinder turbo-intercooler was applied. The injection duration and injection quantity, pilot injection types which are related to CRDI and air/fuel ratio control applied by EVGT were changed simultaneously. Standard experiment procedure constituted dilution apparatus and CPC system to collect nano-particles and these test results were compared with regulated materials of CO, HC, NOx and investigated their relations and characteristics of nano-particles.