• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.681-688
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• 2018

As environmental regulations have been strengthened and high fuel efficiency has been in demand in recent years, the number of ships using natural gas as a fuel is increasing. The demand for ships using LPG or methanol, which are emerging as eco-friendly vessel fuels, is also increasing. In this perspective, ME-LGI engines using LPG or methanol as a fuel have attracted considerable attention. Ships equipped with an ME-LGI engine are required to check the reliability of the fuel injection valve during shipping. This means that the development of a fuel injection valve tester is essential for the commercialization of ME-LGI engine. This study conducted the conceptual design of a fuel injection valve tester for ME-LGI engines using a system engineering process in the order of requirements analysis, functional analysis, and design synthesis. In the requirement analysis stage, the operating process of fuel injection valve was analyzed, and the necessity of checking the sealing oil leakage was then derived. In the functional analysis stage, the functions and flow of them were defined at each functional level. In the design synthesis stage, the equipment for each function was set and the process block diagram based on it was derived. In addition, preliminary risk analysis was performed as a part of system analysis and control, and safety measures were added to the conceptual design. This study is expected to be a good reference material for the concept design of other systems in the future because it shows the application process of a system engineering process to the conceptual design in detail.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.2
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• pp.79-86
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• 1995

Frequency response method is used to design hydraulic servo systems and improve its performance. In this study a method is proposed to get simply the frequency response of the electro-hydraulic servo system which use PWM controlled high-speed on-off valves. Firstly, the describing function of the PWM element is derived and tested. It is found that the character- istic of PWM element could be approximated to a saturation characteristic in the range of allowable frequency. And the dynamic characteristic of the valve-cylinder system could be negligible. The working characteristic of high-speed on-off valve is considered as time delay. So simulation is performed in the basis of the reconstructed block diagram. And this method is verified by experiments.

• Journal of Chest Surgery
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• v.18 no.3
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• pp.436-439
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• 1985

A patient of Ebstein`s anomaly underwent surgical repair on Oct. 24th, 1984. Tricuspid valve was replaced by 31mm St. Jude mechanical valve without plication of atrialized right ventricle. The annulus has been placed below the coronary sinus, with care not to damage the conduction system. But postoperatively complete heart block developed. Permanent pacemaker was implanted on his 12th POD. Now he has been followed up for 9 months. There was no hemodynamic problems yet.

• The Korean Journal of Pain
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• v.6 no.2
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• pp.255-257
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• 1993

Shoulder Hand Syndrome is used to describe painful disabilities of the upper extremity due to disturbances of sympathetic nerve supply. A 72 year old male developed hemiplegia on left side on the 5 days after open heart surgery of aortic valve replacement. Three months later, the patient complained of severe pain in the left upper extremity involving shoulder. The left hand showed swelling and flaccid paralysis. Thereafter the left stellate garglion block with 10 ml of l% lidocaine produced prompt pain relief. Thereafter the patient received 94 stellate ganglion block during 7 months which produced permanent remission of pain throughout a 1 year follow period. We recommand sympathetic block for of Shoulder Hand Syndrome following hemiplegia.

• Journal of Chest Surgery
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• v.26 no.3
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• pp.196-203
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• 1993

Fourty-five cases of operation were performed for the correction of tricuspid regurgitation [TR] in Pusan National University Hospital between 1982 and 1991.The mean age of the patients was 32.6 years and female was dominant[M:F=1:2.2].Isolated tricuspid regurgitation was rare and 43 patients underwent concomitant other valvular operation including mitral valve replacement. Functional cause was in 39 cases and organic lesions were found in 6 cases. Operative methods were Kay annuloplasty[29], De Vega annuloplasty[12], and tricuspid valve replacement[4]. Ring annuloplasty was not performed. Operative mortality rate was 11.1%[5/45] and late mortality rate was 6.7%[2/30]. The tricuspid valve surgery itself was not a serious risk factor for hospital death and no heart block nor thrombosis was complicated. By echocardiogram early[within 30 days] and late [mean:4.9years] changes of postoperative TR were evaluated. De Vega annuloplasty seemed to bring better late result than Kay annuloplasty[p<0.05]. In four patients with late severe TR,previously replaced tissue valve degeneration[2], pulmonary hypertension[1] and rheumatic TR[1] were the possible causes. This experience suggests that De Vega annuloplasty can be a reliable method in the majority of patients with moderate-to-severe functional TR.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.5
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• pp.82-89
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• 1995

The three-dimensional fluid motion through the intake port and cylinder of a single DOHC SI engine was investigated with a commercial computational fluid dynamics simulation program, STAR-CD. This domain includes the intake port, intake valves and combustion chamber. Steady induction port flows for various valve lifts have been simulated for an actual engine configuration. The geometry was obtained by direct interface with a three-dimensional CAD software for complicated port and valve shape. The computational grid was generated using the commercial preprocessor ICEM CFD/CAE. Detailed procedures were presented on the generation of the geometry and the block-structured mesh. A standard k-${\varepsilon}$ turbulent model was applied to consider the complexity of the geometry and the fluid motion. The global flow patterns and the distributions of various quantities, such as pressure, velocity magnitude around the valve seat etc., were examined. The computational results, such as mass flow rate, discharge coefficient etc., for various valve lifts were compard with the experimental results and the computational results were found in good agreement with the experiment.

• Tribology and Lubricants
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• v.40 no.1
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• pp.24-27
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• 2024

A monotype valve body for a dual clutch transmission has the potential to reduce costs, weight, and manufacturing time by modularizing various parts, including those of existing solenoid packs and valve bodies, into one through the application of super-precision die casting technology. However, this approach may lead to challenges such as reduced rigidity and increased interference due to modularization and compactness, impacting both product performance due to the reduced weight as well as durability and reliability. Unlike existing products, this approach requires a high-precision thin-wall block to avoid more complicated flow line formation, interference between flow lines, and leaks, as well as a strict quality requirement standard and precise inspections including detection of internal defects. To conduct precise inspections, we built an equivalent model corresponding to a driving distance of 300,000 km. Testing involved simulating actual road loads using a real vehicle and a chassis dynamometer in the FTP-75 mode (EPA Federal Test Procedure). The aim of the study was to establish a vehicle load-based part durability model for manufacturing a mono-type valve body and to develop fundamental technology for part weight reduction through preliminary design by introducing analytical weight reduction technology based on the derived results.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.3
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• pp.28-38
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• 2003

Finite element analysis of cylinder heat/block compound under assembly, thermal and firing condition were performed. FE model including two cylinders with gasket, head bolts, liners and valve seats was used. FE modeling method and boundary conditions were introduced. Stress distribution and deformation of cylinder head and block under each loading condition were presented. Gasket pressure distribution and bore distortion level were predicted. Measured data of bore distortion was compared with the analysis results. The analysis result showed similar trends with the experimental data. High cycle fatigue analysis on the basis of this result has been performed in order to find the critical areas of the engine assembly.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.3
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• pp.147-158
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• 1997

This paper presents the analysis technique and procedure of main engine components-cylinder block, cylinder liners, gasket and cylinder head-using the finite element method, which aims to assess mainly the potential of lower oil consumption in a view point of engine design and to decide subsequently the accuracy of engine design which was done. The F.E. model of an engine section consisting of one whole cylinder and two adjacent half cylinders is used, whereby the crankcase is cut off at the block bottom deck. By means of a 3-dimensional F.E. model-including cylinder block, liners, gasket, cylinder head, bolts and valve seat rings as separate parts a linear analysis of deformations and stresses was performed for three different loading conditions;assembly, thermal and gas loads. For the analysis of thermal boundary conditions also the temperature field had to be evaluated in a subsequent step.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.3 s.168
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• pp.123-129
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• 2005

The unbalance of the power output, noise, and vibration is happened by the disproportionate pressure variation in the cylinder. For this reason, decrease of the pressure in the cylinder and increase of the residual gas effect on the engine performance. If the abnormal combustion is continued, the crack would be occurred in the engine block. And it could be broken down. For the normal combustion of the SI engine, it is important to supply the balanced mixture by each operating condition. In this study, it was tested the combustion characteristics in the cylinder according to the abnormal adjusting of intake & exhaust valve. This test is willing to set a basic data's analysis fur developing an automotive diagnosis system by analyzing the pressure in the cylinder, the output signal of MAP sensor, the exhaust gas, etc.