• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.481-487
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• 1997

The development of transportation and construction equipment has required higher engine power and lower operation cost. The sound which the engine emits often degrade the performance of the whole system which adopts that engine. Specially the marine engine requires high restriction on the noise level for the customer's comfort and safety. The noise and vibration of Diesel engine must be carefully considered in the early design step. The double antivibration system is effective to increase the efficiency of antivibration, and the acoustic enclosure for reducing the noise level. 2 DOF model was effective to estimate the antivibration performance, which allows to determine the mass of the engine bed and the specification of the engine mount. The mass distribution of the enclosure system can be considered effectively by using the FEM model. The design contains structurally rigid engine bed by FEM, which is for reducing the influence of the flexible vibration, rubber mount selection as well as the acoustic enclosure design.

• Laser Solutions
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• v.5 no.3
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• pp.15-20
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• 2002

The principal obstacle to selection of a laser processing method in production is its relatively high equipment cost and the natural unwillingness of production supervision to try something new until it is thoroughly proven. The major objective of this work is focused on the combined features of gas tungsten arc and a low-power cold laser beam. In this work, the laser beam from a 7 watts carbon monoxide laser was combined with electrical discharges from a short-pulsed capacitive discharge GTA welding power supply. When the low power CO laser beam passes through a special composition shielding gas, the CO molecules in the gas absorbs the radiation, and ionizes through a process blown as non-equilibrium, vibration-vibration pumping. The resulting laser-induced plasma(LIP) was positioned between various configurations of electrodes. The high-voltage impulse applied to the electrodes forced rapid electrical breakdown between the electrodes. Electrical discharges between tungsten electrodes and aluminum sheet specimens followed the ionized path provided by LIP. The result was well-focused melted spots.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.3
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• pp.302-309
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• 1996

Cavitation erosion-corrosion implies damage to materials due to the shock pressure or shock wave that results when bubbles form and collapse at a metal surface within a liquid. If the liquids corrosive to the material, a condition typically encountered in industry, the component materials may suffer serious damage by a combination of mechanical and electrochemical attack. To suppress cavitation erosion as well as cavitation erosion-corrosion to hydraulic equipments, innovations such as the improvement in the geometric design of the equipment or the selection of suitably resistant construction materials are necessary. This study was tested by using the piezoelectric vibrator with 20kHz, 24${\mu}$m for cavitation generation. And also, the vibratory cavitation erosion-corrosion tests on commercial mild steel SS41were carried out. We carefully observed the erosion pattern and surface photography. The geometrical mechanism of pit growth, which is to be likely these processing; shallow typelongrightarrowundercut typelongrightarrowwide shallow type.

• Ceramist
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• v.22 no.4
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• pp.368-380
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• 2019

A ceramic is used as a key material in various fields. Accordingly, the use of scanning electron microscopy is increased for the purpose of evaluating the reliability and defects of advanced ceramic materials. The scanning electron microscope is developed to overcome the limitations of optical microscopy and uses accelerated electrons for imaging. Various signals such as SE, BSE and characteristic X-rays provide useful information about the surface microstructure of specimens and, the content and distribution of chemical components. The development of electron guns, such as FEG, and the improved lens system combined with the advanced in-lens detectors and STEM-in-SEM system have expanded the applications of SEM. Automated SEM-EDS analysis also greatly increases the amount of data, enabling more statistically reliable results. In addition, X-ray CT, XRF, and WDS, which are installed in scanning electron microscope, have transformed SEM a more versatile analytical equipment. The performance and specifications of the scanning electron microscope to evaluate ceramics were reviewed and the selection criteria for SEM analysis were described.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.05a
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• pp.135-138
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• 2006

OLEDs are attractive because of possible application in display with low operating voltage, low power consumption, self-emission and capability of multicolor emission by the selection of emissive material. We investigated the effects of deposition rate on the electrical characteristics, physical characteristics and optical characteristics of OLEDs in the ITO(indium-tin-oxide)/N,N'-diphenyl-N,N'-bis(3-methyphenyl)-1,1'-biphenyl-4,4'-diamine(TPD)/tris(8-hydroxyquinoline)aluminum($Alq_3$)/Al device. We measured current density, luminous flux and luminance characteristics of devices with varying deposition rates of TPD and $Alq_3$. It has been found that optimal deposition rate of TPD and $Alq_3$ were respectively $1.5{\AA}/s$ from the device structure. An AFM measurement results, surface roughness of the deposited film was the lowest when deposition rate was $1.5{\AA}/s$.

• Journal of the Korean Society for Railway
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• v.9 no.1 s.32
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• pp.110-117
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• 2006

Boulder detection methods and its compensation is discussed with consideration of boulder conditions in soft ground tunneling by shielded TBM. For analysis of proper compensation methods for boulder obstruction, its removal costs and cases on eight projects are presented. Compensation for boulder obstruction removal by volume or weight is not practical for most tunneling situation, but compensation by crew time is probably the most equitable method. If boulders are anticipated on project, boulder removal plan must be considered with proper equipment selection.

• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.175-181
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• 2001

In compliance with the Industrial Safely and Health Acts, the owners/users have performed self-inspection at regular intervals to secure safety in the use of hazardous machinery, equipment and facilities However, securing safety, which is the goal of self-inspection, has not been thoroughly understood in most small businesses and factories. The objective of this research is to analyze the importance and effects of self-inspection in preventing accidents in businesses and factories that use hazardous machinery and facilities. The result shows that self-inspection has made a good contribution to the prevention of accidents. Most businesses and factories that responded the survey answered they have improved safety in the use of machinery and facilities through self-inspection, though the ways of self-inspection were not all the same. However, the result also reveals that there are rooms for further improvement in the areas of self-inspection intervals, self-inspection methods and the selection of self-inspection objects. This improvement is necessary to improve the effect of self-inspection and to minimize regulations of the government on business activities.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.3
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• pp.474-481
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• 2011

The Electronic Warfare Computer for the Aircraft Survivability Equipment will improve the ability for countermeasures by analysis about threat information. This paper suggests method that threat data integration of multiple sensors(Radar Warning Receiver, Laser Warning Receiver, Missile Warning Receiver). The algorithm of threat data integration is based on detected threat sequence and azimuth information. The threat sequence information is analyzed in advance and the azimuth data is received from sensors. The suggested method is evaluated through simulation under the environment like real helicopter.

• Korean Institute of Interior Design Journal
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• v.14 no.3 s.50
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• pp.28-35
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• 2005

This study is focused on the characteristics of organization types of activity diagrams for experimental residential design. Diagrams became one of the crucial design methods to rationally generate a definite spatial form that contains indefinite human activities In contemporary architecture. Particularly in residential design, activity diagrams based on the occupants' behavioral patterns have been critically important. 'Scientific Management in the Home' by mathematical calculation and the Archigram's 'Living 1990' equipped with innovative technologies are the representative examples in modern architecture. The study is focused on the experimental residential projects since 2000 and three main types of activity organization were discovered: 'Weaving through Circulation';'Flexible Space by Equipment' and 'Activity Selection by Open-Close System'. Two projects from each type are analyzed in detail to further develop the comparison study. The study is concluded that, although the architect's preconceived . philosophical background has an important role, activity organization should smoothly derive from the unique conditions of the project such as the characteristic of the occupant itself.

• ETRI Journal
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• v.36 no.6
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• pp.953-959
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• 2014

This paper studies the uplink resource allocation for multiple radio access (MRA) in reconfigurable radio systems, where multiple-input and multiple-output (MIMO) multicarrier-code division multiple access (MC-CDMA) and MIMO orthogonal frequency-division multiple access (OFDMA) networks coexist. By assuming multi-radio user equipment with network-guided operation, the optimal resource allocation for MRA is analyzed as a cross-layer optimization framework with and without fairness consideration to maximize the uplink sum-rate capacity. Numerical results reveal that parallel MRA, which uses MC-CDMA and OFDMA networks concurrently, outperforms the performance of each MC-CDMA and OFDMA network by exploiting the multiuser selection diversity.