• Journal of Ocean Engineering and Technology
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• v.12 no.1
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• pp.76-84
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• 1998

In this 1st report, the relationship between pure creep properties and initial strain was studied and also its acoustic emission test was performed during creep test at 500, 600 and $700^{\circ}C$. And the applicability of the acoustic emission technique was investigated to analyze the quantitive relationship between all the pure properties (creep strength, creep repture time or creep life, steady state creep rate, total creep rate, creep strain, total creep strain, etc.) and the initial strains as well as to analyze AE properties during the pure creep loading condition.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.409-414
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• 2005

This study is based on the recent CISPR(International Special Committee on Radio Interference) research which is focused on the Radiated Emission test method above 1 GHz and explained "w"(Measurements dimension) for the antenna's $\theta_{3dB}$ characteristic. And expound the work in progress in the IEC Standard for the measurement methods and the limits above 1 GHz.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.5
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• pp.213-218
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• 1997

CNG dual fuel engine for heavy duty diesel engine has been equipped to a Korean bus engine and tested to compare th engine performance and the emission characteristics with the existing diesel fueled engine. The results are summarized as follows. Diesel fueled engine has the fuel injection timing of BTDC17°. The injection timing of CNG modified engine is retarded to BTDC14° for reduction of NOx. Performance optimization has been carried out to have engine power equivalent to or better than the diesel fueled engine. Smoke is decreased by 85% by Korean smoke 3 mode test. By 6 mode test CO is increased by 313% and THC is increased by 1407%. NOx is decreased by 27%. Even though THC is increased very much, it's not too serious problem since CO and THC emission of diesel engine are very little compared to gasoline engine and THC don't give bad effect on human health. But the reduction technologies of CO and THC need to be considered.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.921-924
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• 2004

This paper is to investigate a crack for plasma sprayed MCrAlY coated material by acoustic emission method in 4-point bending test. The CoNiCrAlY is coated on Inconel-718 by vacuum plasma spray process. Micro-hardness measurement was conducted by means of Micro Vickers-hardness indentor. The porosity of coating layer was measured using a SEM and Image Analyzer. AE monitoring system is composed of PICO type sensor, a wide band preamplifier(40dB), a PC and AE DSP(16/32 PAC) board. The AE count, Hit and energy of coating specimens is measured according to coating thickness.

• Journal of Power System Engineering
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• v.2 no.3
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• pp.49-54
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• 1998

This paper is investigated of hardness and adhesiveness of plasma sprayed coating steels by AE(Acoustic Emission) testing when loading a tensile. AE Parameters used are Event, Count, Energy and Amplitude. Test specimens are carbon steel(S45C) with sprayed coating layers of Ni-4.5wt.%Al(bond coating) and $TiO_2$(top coating), and carry out heat treatment at $800^{\circ}C\;and\;1000^{\circ}C$, respectively. The micro-hardness of the heat treatment specimen have been improved more than that of non-heat treatment. On the tensile test, the process and occurence of the exfoliation of the sprayed coating layer can be estimated by AE Characteristics of AE parameters, such as event, count, amplitude and energy, on the layer exfoliation are shown the similar aspects. The exfoliation of bond coating occure at about 20% of strain and top coating is about 5% of strain.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.8
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• pp.419-422
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• 2001

This paper presents the principle and fabrication of a novel micro mass spectrometer and emission test of hot electron for ionization. A micro mass spectrometer consists of a micro ion source and a micro ion separator. The micro ion source consists of a hot filament and grid electrodes. Electrons emitted from a hot filament are to ionize some sample molecules. The ions are accelerated to an ion detector by an electric field. Mass can be analyzed by using the time of fight depending on the mass-to-charge ratio. The current of hot electron emission from the hot filament is measured for various input voltages.

• Smart Structures and Systems
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• v.13 no.1
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• pp.155-171
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• 2014

Various monitoring techniques are now available for structural health monitoring and Acoustic Emission (AE) is one of them. One of the major advantages of the AE technique is its capability to locate active cracks in structural members. AE crack locating approaches are affected by the signal attenuation and dispersion of elastic waves due to inhomogeneity and geometry of reinforced concrete (RC) members. In this paper, a novel technique is described based on signal processing and sensor arrangement to process multisensory AE data generated by the onset and propagation of cracks and is validated with experimental results from an in-situ load test. Considering the sources of uncertainty in the AE crack location process, a methodology is proposed to capture and locate events generated by cracks. In particular, the relationship between AE events and load is analyzed, and the feasibility of using the AE technique to evaluate the cracking behavior of two RC slab strips during loading to failure is studied.

• Journal of the Korea Concrete Institute
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• v.12 no.3
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• pp.67-75
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• 2000

It was well recognized that the damages associated mainly with the aging of civil infrastructures were one of very serious problems for assurance of safety and reliability. Recently carbon fiber sheet(CFS) has been widely used for reinforcement and rehabilitation of damaged concrete beam. However, the fundamental mechanism of load transfer and its load-resistant for carbon fiber sheet reinforced concrete are not fully understood. In this study, three point bending test has been carried out to understand the damage progress and the micro-failure mechanism of CFS reinforced mortars. For this purpose, four different types of specimens are used, that is, mortar, steel bar reinforced mortar, CFS reinforced mortar, and steel bar and CFS reinforced morter. Acoustic Emission(AE) technique was used to evaluate the characteristics of damage progress and the failure mechanism of specimens. in addition, two-dimensional AE source location was also performed to monitor crack initiation and propagation processes for these specimens.

• Journal of Environmental Impact Assessment
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• v.5 no.1
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• pp.69-77
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• 1996

The variations of ozone concentration and the sensitivity test for VOC emission intensities was investigated by means of a PBM(Photochemical Box Model). Compared to monitoring data, the typical variations of $NO_2$, CO, $O_3$ for days were successfully reproduced. Model results revealed that maximum ozone concentration got increased with the increase of VOC emission, that is, VOC played the important role in producing the photochemical smog.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.5
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• pp.86-96
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• 2000

This study is to consider that the helical intake port flow and fuel injection system have effects on the characteristics of engine performance and emissions in a turbocharged DI diesel engine of the displacement 9.4L. The swirl ratio for ports was modified by hand-working and measured by impulse torque swirl meter, For the effects on performance and emission, the brake torque, BSFC were measured by engine dynamometer and NOx, smoke were by gas analyzer and smoke meter. As a result of steady flow test, when the valve eccentricity ratio are closed to cylinder wall, the flow coefficient and swirl intensity are increased, And as the swirl is increased, the mean flow coefficient is decreasing, whereas the gulf factor is increasing. Also, through engine test its can be expected to meet performance and emission by the following applied parameter; the swirl ratio is 2.43, injection timing is BTDC $13^{\circ}$CA and compression is 15.5.