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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Marine Engineering
Journal Basic Information
Journal DOI :
Korean Society of Marine Engineers
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Volume & Issues
Volume 19, Issue 4 - Aug 1995
Volume 19, Issue 3 - Jun 1995
Volume 19, Issue 2 - Apr 1995
Volume 19, Issue 1 - Feb 1995
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A study on the spray and flame by optically accessible D.I. diesel engine : analysis by Schlieren method and diffused background illumination method
Journal of the Korean Society of Marine Engineering, volume 19, issue 3, 1995, Pages 9~23
To analyze the spray and flame in D.I. diesel engine, the visualizing methods by schlieren photograph and diffused background illumination photograph with high speed camera are applied to optically accessible D.I.diesel engine. Wcaporating spray, spray droplets and brightness flame are taken with high speed camera by visuallizing method in accordance with various suction air temperature and injection time. The spray and flame image on the film was analyzed by image analyzer. The optically accessible D.I. diesel engine had the similar pressure characteristic to the real D.I. diesel engine. Experimental results showed that shadow areas of the evaporating spray were extended at higher suction air temperature, spray droplets had a max. Penetration length and their penetrating patterns were dependent on the surrounding gas temperature, and flame size after ignition was largely governed by the evaporated fuel quantity at ignition point and by the surrounding gas condition due to piston motion.
A study on the scavenging characteristics in slow-speed two-stroke diesel engines
Journal of the Korean Society of Marine Engineering, volume 19, issue 3, 1995, Pages 24~32
The scavenging characteristics have a great influence on the performance of a diesel engine, especially slow-speed two-stroke diesel engines which are usually used as a marine propulsion power plant, and they are greatly affected by the conditions in the cylinder, intake and exhaust manifolds, and the opening and closing timing of scavenging ports or exhaust valves during the gas exchange process. Besides, there are many other factors to affect the scavenging characteristics and these factors interact each other very complicatedly. Therefore the simulation program of the gas exchange process is very useful to improve and predict the scavenging characteristics, due to the high costs associated with redesign and testing. In this paper it was attenpted to investigate the effect of the variation of the pressure ratio of intake to exhaust manifolds, and the variation of the opening and closing timing of a exhaust valve by using a computational program for a three-zone scavenging model which was developed by authors. The computed results showed that the scavenging efficiency and delivery ratio increased considerably, but the trapping efficiency decreased with increasing of the pressure ratio of intake to exhaust manifolds. The scavenging efficiency, trapping efficiency, and th conditions of the cylinder gases were affected by the opening timing of the exhaust valve, but the delivery ratio by the closing timing.
A study on the response characteristics of a turbocharged diesel engine under operation conditions of rapid acceleration
Journal of the Korean Society of Marine Engineering, volume 19, issue 3, 1995, Pages 33~41
The optimum structural modification by shape changes
Journal of the Korean Society of Marine Engineering, volume 19, issue 3, 1995, Pages 42~49
In this study, the optimum structural modification of the L-type structure by shape changes is suggested. The vibration characteristics of L-type structure are analyzed by the sub-structure synthesis method, and the coordinte sensitivities of each sub-structure are calculated and the change quantities of the positions to be modified are suggested by using the coordinate sensitivities. The results obtained are as follows : 1. The sensitivities of the natural frequency could be calculated by the sensitivity analysis. 2. The change quantities of the position to be modified could be suggested by the optimum structural modification method. 3. The developed program could reduce the process and time of computation, since the sensitivity was directly calculated by differential method, not finite difference method.
A study on the brazed bonding of alumina ceramic to aluminum in the air atmosphere
Journal of the Korean Society of Marine Engineering, volume 19, issue 3, 1995, Pages 50~61
In recent years, many ceramic researchers have discoved various methods of joining ceramic to metal. However, most of these joining methods are perfomed under vacuum and pressured circumstances. So, when we join ceramic to metal,the proceedings are very complicated and require a very high cost. The purpose of this study is to develop a new joining method of an alumina ceramic to an aluminum metal in air atmosphere. The joining condition, such as copper metallizing, nickel plating, brazing, etc. was investigated through the shear strength test of the trial joint. The results obtained from the above experimenta are summarized as follows : 1) In the case of the
joint, the shear strength of the joint was affected by the various foctor such as kaolin content, copper metallizing thickness, firing temperature, firing time. 2) The better shear strength of the
/Al joint was obtained when Ni plating was conducted under higher current density than existing plating condition. 3) The shear strength of the
/Al joint increases with the Ni plating thickness is confined to the range of this paper. 4) The shear strength of the thermal-shocked specimen(
/Al joint) was far more deteriorated than that of the as-bonded specimen.
Characteristics of corrosion fatigue strength of TiN coating steel
Journal of the Korean Society of Marine Engineering, volume 19, issue 3, 1995, Pages 62~69
In order to investigate the effect of TiN coating on corrosion fatigue behavior of metal, the rotary bending corrosion fatigue tests were carried out in 3% NaCl solution by using the round bar specimens of high-speed steel, SKH-9, coated with TiN by PVD method. From the experimental results, fatigue strength of TiN coating steel in air was obvious improvement as compared with that of the substrate because of the restriction of dislocation movement in near surface of the substrate by hard thin film. In 3% NaCl solution, corrosion fatigue life of TiN coating specimen in high stress level was improvement same as in air. But in low stress level, corrosion fatigue life of TiN coating one was equivalent to that without coating, due to much crack initiated from corrosion pits formed at the substrate by failure of coating layer.
Optimization of the constrained machining parameters problem by the SUMT
Journal of the Korean Society of Marine Engineering, volume 19, issue 3, 1995, Pages 70~76
A Study on The Adaptive Control of the Rotational Systems by Means of the Normal Model Tracking Method
Journal of the Korean Society of Marine Engineering, volume 19, issue 3, 1995, Pages 77~83
Recently, in the field of industrial servo-systems, several methods have been proposed for tracking the reference input fastly and finely without overshoot. These methods, however, are established under hypothesis that structure and parameters of the plant are known accurately and they are time invariant. In practice, it is difficult to obtain the values of plant's parameters accurately and usually plants change with time and operation conditions. In this paper a method to construct the nominal model tracking adaptive control system is proposed. The system is composed of the nomial model which produces a ideal response and the model tracking system with the fuzzy adaptive controller. If the actual plant is equal to the controlled object in the nominal model, the output of the plant is the same as that of the nominal model and the fuzzy adaptive controller becomes idle. However, when the plant changes, the fuzzy adaptive controller of the tracking system operates in order for the output of the plant to track the ideal response. Through the computer simulations under various conditions, it is confirmed that the proposed model tracking system is very effective.
A Study on the Design of Robust Simulation Controller of Magnetic Levitation System(I)
Journal of the Korean Society of Marine Engineering, volume 19, issue 3, 1995, Pages 84~90
The magnetic levitation system has great advantages, such as little friction, no lubrication no noise and so on. The magnetic levitation system need a stabilizing controller because it is a unstable system in natural. This paper presents the robust stabilizing controller design of the magnetic levitation system. The controller which is designed in this paper by
control theory is robust servo controller which has zero offset in spite of the model uncertainties. The validity of controller was investigater through the response simulation. In the future, we will use the result of this study at the actual magnetic levitation system.
A Comparative Analysis of the Indirect Field-Oriented Control with a Scalar Method for IM Speed Control
Journal of the Korean Society of Marine Engineering, volume 19, issue 3, 1995, Pages 91~98
To control speed or torque of induction motors, scalar control method that regulates the value of stator current had been used conventionally. But, vector control method which contrls the direction and the value of stator current at the same time has been introduced lately and employed widely. This paper describes comparative analyses of above two methods by computer simulation. As a result of the simulation, both methods showed good responses for high speed, but, vector control method characterized much better performance for low speed and sinusoidal input.
A Study on the Design and the Analysis of Hybrid Inverter
Journal of the Korean Society of Marine Engineering, volume 19, issue 3, 1995, Pages 99~106
PWM(Pluse Width Modulation) induction motor drives are being used in greater numvers through a wide variety of industrial and commercial applications. In this paper, a new speed control algorithm (hybrid algorithm) for induction motor drives that uses regular sampled PWM and harmonic elimination PWM is presented. The hybrid algorithm in implemeted on the computer to obtain solutions from the calculation equations of the width of the pulses and the firing angles for the selected harmonic elimination. this paper describes the time delay effects and the suitable compensating methods moreover, optical transmission system for driving signals is proposed and is compared with general trnasmission system. The hybrid inverter was tested with induction motor, and these test results are shown that this hybrid inverter closely approximates and exhibits many of the desirable performance characteristic distortions and eliminated the objectionable harmonics. Finally, detailed experimental investigation of the proposed hybrid scheme in presented.
The Current and Power Waveform Improvement of an AC Motor with Low Pass LC Filter Driven by a Digital Bridge Inverter(I)
Journal of the Korean Society of Marine Engineering, volume 19, issue 3, 1995, Pages 107~118
The characteristics of the current waveforms and 3
power waveforms of the variable speed 3
AC motor system driven by the single-pulse PWM investigated in this paper. The system is composed of a digital bridge inverter and low pass LC filter. It is confirmed that current waveforms and 3
power waveforms can be improved by utilizing the high order low pass LC filter than that of lower order through computer simulation. Also, we propose the low pass LC filter revised from the conventional LC filter.