• 한국자동차공학회논문집
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• 제6권5호
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• pp.162-173
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• 1998

The high pressure common rail injection system offers a high potential for improving emmisions and performance characteristics in large direct diesel engines. High pressures in the common rail with electronic control allows the fuel quantity and injection timing to be optimized and controlled throughout a wide range of engine rpm and load conditions. In this study, high pressure supply pump, common rail, pipes, solenoid and control chamber, and nozzle were modeled in order to predict needle lift, rate of injection, and total injected fuel quantity. When the common rail pressure is raised up to 13.0 ㎫ and the targer injection duration is 1.0ms, the pressure drop in common rail is about 5.0㎫. The angle of effective pressurization is necessary to be optimized for the minimum pump drive torque and high pressure in common rail depending on the operating conditions. The characteristics of injection were also greatly influenced by the pressures in common rail, the areas of the inlet and exit orifice of the control chamber.

• 한국분무공학회지
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• 제6권1호
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• pp.1-8
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• 2001

Fuel injection system is very important in diesel combustion. Recently electronic control of fuel injection system and common rail systems are introduced to reduce the emission and to increase the energy efficiency from diesel engine by control of the injection timing and duration. In this study, evaluation possibility of the system for electronic control by spool valve, one of the accumulator type injection systems with spool valve using solenoid was composed and the operating characteristics were investigated to evaluate the effects of spring coefficient, initial spring force, solenoid driving time, fuel supply pressure on the injection timing and duration. We could confirm the capability that diesel injection was electronically controlled by spool valve.

• Journal of Power Electronics
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• 제15권5호
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• pp.1338-1347
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• 2015

DC injection is a critical issue in transformerless grid-connected inverters. DC injection control based on virtual capacitor has the advantages of low cost, low loss, high accuracy and easy implementation. In this paper, the principle of DC injection control based on virtual capacitor was analyzed. In addition, the applicable conditions, working process, steady state error and advantages were also discussed in detail. The design of the control parameters based on virtual capacitor was proposed in a grid-connected inverter with LCL filter. The robustness of the control parameters was also discussed. Simulation and experimental results verify the validity of the analysis and demonstrate that this research has a certain value in engineering applications.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.500-510
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• 1996

A Direct injection -mixing total -flow -control sprayer was developed and evaluated . The system provided precise application rates and minimized operator exposure to chemicals as well as providing a possibility for recycling container so f unused chemicals that can causes environmental contamination. Chemicals were metered and injected proportionally to the diluent flow rate to provide constant concentrations. The main diluent flow was varied in response to changes in travel speed. Experimental variables of the sprayer were the control interval, the sensitivity of flow regulating valve, the tolerance of control object and the sensitivity of the injection pump system. The optimal performance of the flow control system was with an average response time of 8.5 sec at an absolute steady state of error of 0.067 L/min (0.8% of flow rate). The average response time of the injection rate was -0.53 sec and the coefficient of variation (CV) of concentration was 3.2%.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1995년도 춘계학술대회
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• pp.127-127
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• 1995

The present study was conducted to examine the effect of recombinant bovine somatotropin(${\gamma}$ bST), which was administered to cow to promote milk production, on bST levels in milk. Fourteen cows were divided into two groups: 1) control cows received neither y bST nor vehicle, 2) treated cows were administered twice at two-week interval with 500mg ${\gamma}$ bST each cow by subcutaneous injection. Milk samples were taken on day 0 (prior to injection), day 7 (7 days after 1st injection), day 21 (7 days after 2nd injection) and day 35 (21 days after 2nd injection).

• 대한간호학회지
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• 제28권2호
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• pp.303-318
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• 1998

Cutaneous stimulation and distraction are independent nursing interventions used in various painful conditions, which is explained by gate control theory. This study was aimed at identifying the effect of cutaneous stimulation, distraction and combination of cutaneous stimulation and distraction on the reduction of intravenous injection pain levels of chemotherapy patients. Repeated measurement post test research design was used for one group. Fifty-three cancer patients who received intravenous chemotherapy regulary in outpatient injection rooms of D medical center and Y medical center in Taegu were studied from June 23, 1997 to July 12, 1997. First the intravenous injection pain level of the control period was measured. Second, the intravenous injection pain level of the experimental period using cutaneous stimulation was measured. Third, the intravenous injection pain level of the experimental period using distraction was messured. Fourth, the intravenous injection pain level of the experimental period using a combination of cutaneous stimulation and distraction was measured. The instruments used for this study were a visual analogue pain scale as subjective pain measurement and an objective pain behavior checklist. Analysis of data was done by use of repeated measure ANOVA, bonferni, t-test, and F-test. The results of this study were summerized as follows : 1) The first hypothesis that the subjective pain score of intraveneous injection pain in the experimental period with cutaneous stimulation will be lower than in the control period was rejected. 2) The second hypothesis that the objective pain behavior score of intravenous injection pain in the experimental period with cutaneous stimulation will be lower than in the control period was accepted(F=24.23, p=0.0001, Bornferni p<.05). 3) The third hypothesis that the subjective pain score of intraveneous injection pain in the experimental period with distraction will be lower than in the control period was rejected. 4) The fourth hypothesis that the objective pain score of intravenous injection pain in the experimental period with distraction will be lower than in the control period was accepted(F=24.23, p=0.0001, Bornferni p<.05). 5) The fifth hypothesis that the subjective pain score of intravenous injection pain in the experimental period with combination of cutaneous stimulation and distraction will be lower than in the control period was accepted(F=3.04, p=0.031, Bonferni p<.05). 6) The sixth hypothesis that the objective pain score of intravenous injection pain in the experimental period with combination of cutaneous stimulation and distraction will be lower than in the control period was accepted(F=24.23, p=0.0001, Bonferni p<.05).

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1383-1388
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• 2015

Proportional integral derivative (PID) control is one of the conventional control strategies. Industrial PID control has many options, tools, and parameters for dealing with the wide spectrum of difficulties and opportunities in manufacturing plants. It has a simple control structure that is easy to understand and relatively easy to tune. Injection mold is warming up to the idea of cycling the tool surface temperature during the molding cycle rather than keeping it constant. This “heating and cooling” process has rapidly gained popularity abroad. However, it has discovered that raising the mold wall temperature above the resin’s glass-transition or crystalline melting temperature during the filling stage is followed by rapid cooling and improved product performance in applications from automotive to packaging to optics. In previous studies, optimization methods were mainly selected on the basis of the subjective experience. Appropriate techniques are necessary to optimize the cooling channels for the injection mold. In this study, a digital signal processor (DSP)-based PID control system is applied to injection molding machines. The main aim of this study is to optimize the control of the proposed structure, including a digital PID control method with a DSP chip in the injection molding machine.

• Archives of Plastic Surgery
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• 제33권6호
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• pp.742-747
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• 2006

Purpose: The purpose of this study was to evaluate the role of mast cell and histamine as typical product of mast cell in ischemia-reperfusion injury of muscle flap using H2 receptor blocker and mast cell stabilizer. Methods: Thirty-five Sprague-Dawley rats weighing 250-300 gm were divided into four groups; Group I: Control group without ischemia, Group II: Normal saline injection group with ischemia, Group III: Cimetidine injection group with ischemia, Group IV: Sodium cromoglycate injection group with ischemia. Well established single pedicled transverse rectus abdominis musculocutaneous(TRAM) flap was designed in all rats and were rendered ischemia by clamping the artery for 150 minutes. All injections were applied intramuscular around gluteal area 30 minutes before reperfusion. The flap survival was evaluated at 7 days after operation. Neutrophil counts and mast cell counts were evaluated 24 hours after reperfusion. Results: The difference of skin flap survival between control group and cimetidine injection group was not significant. In the normal saline injection group flap survival was markedly decreased compared to that of control group. The muscle flap survival was similar to the results of skin flap survival. The neutrophil counts were significantly decreased in control group and sodium cromoglycate injection group than normal saline injection group. The mast cell counts were significantly decreased in cimetidine injection group and control group than both normal saline injection and sodium cromoglycate injection groups. The protective effect of sodium cromoglycate was not seen in the skin flap, but the muscle flaps showed protective effects of sodium cromoglycate compared to normal saline injection group. Conclusions: It is suggests that commonly used antihistamine(H2 receptor blocker) has protective effect against ischemia-reperfusion injury to skin and muscle flaps by reducing neutrophil and mast cell. The mast cell stabilizer was not effective for skin flap but, possibly, for muscle flap.

• Design & Manufacturing
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• 제15권3호
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• pp.56-61
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• 2021

The increase in automation facilities in the injection molding industry is a very important process control item. The most important item when constructing an unmanned machine using a take-out robot is the "mold opening stroke" of the mold. The injection molding machine control method is divided into hydraulic type and electric type, and there have been few studies on the mold opening distance according to the control method. In this study, the correlation was confirmed by increasing the injection speed to 20, 50, 80, and 100% for the three types of hydraulic control method, open loop and close loop, and electric control method. Through the experiment, the following results were obtained. (1) It can be seen that the reproducibility is excellent with the electric, close loop, and open loop control methods. (2) When the injection speed is set to 50%, the mold opening distance is 263.10~263.27 mm, which is the most reproducible. (3) As a result of ANOVA, both injection speed and mold opening distance showed a significant difference in the hydraulic control method (p<0.05), but it was verified through experiments that there was no significant difference in the electric control method. Based on these results, when electric control is selected rather than hydraulic control, the reproducibility of the mold opening distance is excellent, so it is thought that the taking-out robot can take the object out of the mold more safely.

• 소성∙가공
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• 제12권8호
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• pp.738-743
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• 2003

The major problems of a plastic injection mould can be devided into two kinds, one is in mould another in injected parts. Most of defects of the former comes from mould design, such as, structure and working. The latter are weld line, warpage, sink mark, burning, flow mark, scratching, shading, black hole and so on. Most of problems in injection molding are difficult to find the reason because of complexity. The purpose of this paper is to improve the quality of plastic injection mould and parts with inquiring the counter plan and analizing troubles of the part of Flat TV Front Cover by flow control method and gas-assisted injection moulding. For minimizing defects of the injection moulded parts, computer aided simulation method for injection mould filling was used. Based on these numerical results, the guidelines of mould design and injection processing condition were established. As a result, the improvement of quality, such as minimizing surface defects of injection moulding parts and troubles in mould was achieved.