• Journal of the Microelectronics and Packaging Society
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• v.10 no.1
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• pp.39-43
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• 2003

Thermal management is very important for the success of high density circuit design in LTCC. In this paper, LTCC substrates containing thermal via and pad were fabricated in order to study the influence of the thermal dissipation. To realize the accurate thermal analysis for structure design, a series of simple thermal conductivity measurement by laser flash method and parametric numerical analysis have been carried out. The LTCC substrate including via and Ag pad has good thermal conductivity over 103 W/mK which is 44% value of pure Ag material. Thermal behaviors with via arrays, size and density in the LTCC substrate were studied by numerical method.

• Tribology and Lubricants
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• v.29 no.6
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• pp.386-391
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• 2013

Part I of this study analyzed the effects of tilting pad bearing designs to reduce the stiffness of the bearings used in a process high-speed lightweight centrifugal compressor intended for a domestic refinery use. This was done in an attempt to enhance the robustness of its rotordynamic stability against possible aerodynamic cross-coupled stiffness. The bearing design variables reviewed were the clearances, LBPs, LOPs, and preloads. The results showed that there was practically no difference between the LBP and LOP designs in terms of the bearing stiffness, because the compressor rotor was lightweight and the bearings had relatively high preloads. Increasing both the machined and assembled clearances in bearing designs has resulted in the bearing stiffness being greatly reduced. In addition, it has been confirmed that an additional reduction in the bearing stiffness can be obtained for given fixed machined clearances by decreasing the preloads, i.e., by increasing the assembled clearances.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.57-61
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• 2004

in order to improve the quality of the sheared surface in cutting of sandwich sheet metals the cut-off operation is mainly investigated which is the typical shearing process in sheet metal forming technology. For experiments the cut-off die is made which can be easily adjusted by die design variables such as blankholding force, pad force, and clearance. The sheet metals chose as specimen are clad304(STS304-Al1050-STS304) and anti-vibration sheet metal. The shearing process is visualized by the computer vision system installed in front of the cut-off die and the sheared surface before and after cut-off operation is measured and quantitatively compared with the help of the optical microscope. From test results the good sheared surface was shown when the clearance gets small with large blankholding force.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.869-874
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• 2001

In order that precision equipment using high precision industrial operate normally. vibration criteria of expected area that equipment be set up is micrometer level. that method is a trust design for apply to in field, when there attend to quantifiable method. Hence, semi -empirical method that using on the basis of experimental data about undefined information (properities of vibration source, dynamic properities of structure, etc.,) for prediction of vibration response make the use of dynamic structure design of semiconductor ＆ TFT-LCD in the inside and outside country. Like this, for doing an optimal design of dynamic about structure, it is best important to get trust data that apply to semi-empirical method that is method of prediction vibration level. In this paper, on the basis of experimental data which was offered by a manufacturing company Of precisin equipment that plan to set up in semiconductor factory, we predicted vibration response on expected area that equipment be set up.

• Journal of the Korean Home Economics Association
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• v.48 no.2
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• pp.85-94
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• 2010

Comparative analysis of marker efficiency in blouse patterns, based on different sleeve designs, was carried out. Sleeve designs used included set-in-sleeve, laglan sleeve, and epaulet sleeve. The two types of epaulet sleeves, A and B, are based on pattern arrangement methods of center back. Cloth and production conditions are the width of cloth, the number of marking pieces, and the direction for marking deployment. A blouse pattern saved to the PAD CAD System was graded with different sizes and arranged for industrial purpose to calculate the marker efficiency in different conditions. The results were as follows. On the whole, the marker efficiency of small pattern sized set-insleeve was higher than laglan and epaulet sleeve designs. It was also established that marker efficiency is dependent on cloth and production conditions. For small number of marking pieces, efficiency was higher in the condition of 110cm cloth widths compared with that condition of 150cm cloth widths. However the efficiency of large number of marking pieces was higher in the condition of 150cm cloth widths.

• Journal of Drive and Control
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• v.15 no.3
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• pp.43-48
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• 2018

The hydraulic control valve, used in the CPB (cold-pad-Batch) cold dyeing system, passes through a pressurized material that absorbs the dye. The hydraulic control of the hydraulic control panel shall be driven in a uniform and precisely controlled manner, as it interferes directly with the dyschromatism. In this study, an acceleration test model was employed to verify the durability of the hydraulic control of the hydraulic control panel, which was manufactured by the scenic model, and the pre-roll angle was analyzed before the performance of acceleration test. Based on the change in the amount of deformation of the padder roll the durability of the padder roll was analyzed along with verification of the durability of the skin and the rubber coating in contact with the fabric. Furthermore, the accelerated test method used for hydraulic controlled multi-cell padder rolls was verified.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.2
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• pp.288-295
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• 2012

Recently personal income level is rising. So, many people use the leisure lightweight aircraft and the population which enjoys a leisure is increasing. But as the leisure lightweight aircraft compares in the civil aircraft and the military aircraft, and it has a low price. So the equipment which it is loaded in the lightweight aircraft is not equipped. In this paper, we develop the air navigation for lightweight aircraft using the smart phone(iPhone, Android phone, Window mobile, BADA phone etc.) and the smart pad(iPad, Galaxy Tab etc.).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.4
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• pp.337-345
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• 2009

This paper investigates the reliability of district heating pipes at thermo-elastic fatigue loading. District heating pipes, subjected to $120^{\circ}C$ and $16kg_f/cm^2$ due to water distributing service through inside the pipes, should endure long term cyclic thermal-mechanical loadings. The heating pipes are the co-centric tubes of steel pipe, poly urethane(PUR) insulator, and high density poly ethylene(HDPE) case. On installation, foam pad is externally wrapped for accommodating stress reduction near the bend sections of pipes. However, there have been frequent reports on the failures of bend sections in the middle of long term service. This study scrutinizes the observed failures near the bend sections through applying the finite element methods. Specially in this study, heating pipes are studied on the influence of foam padding on failures and proposed new designs for reinforced bend without foam pad.

• Journal of Applied Reliability
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• v.7 no.1
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• pp.23-29
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• 2007

Probe card is a test component which is to classify the known good die with electrical contact before the packaging in the ATE (automatic testing equipment). Conventional probe tip was mostly needle type, it has been difficult to meet with conventional type, because of decreasing chip size, pad to pad pitch and pads size increasingly. For that reason, probe cards using MEMS (micro electro mechanical system) technology have been developed for various semiconductor chips. In this paper, Area Array type MEMS Probe tip was designed,, fabricated, and characterized its mechanical and electrical properties. The authors found that good electrical characteristics under $1{\Omega}$ were acquired with gold (Au) and aluminium (Al) pad contact test over 0.5gf and 4gf respectively. And, contact resistance variation under $0.1{\Omega}$ were achieved with 100,000 times of repetition test. And, insertion loss (IS) for high frequency operation was ascertained over 300MHz at -3dB loss.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.5
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• pp.520-526
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• 2016

Squeal noise is a typical brake noise that is annoying to both passengers and pedestrians. Its frequency range is fairly wide from 1 kHz to 18 kHz, which can be distressful to people. The brake squeal noise occurs due to various mechanisms, such as the mode coupling of the brake system, self-excited vibration, unstable wear, and others. In this study, several parameters involved in the generation of a squeal noise are investigated experimentally by using a brake noise dynamometer. The speed, caliper pressure, torque, and friction coefficient are measured as functions of time on the dynamometer. The contact pressure and temperature distributions of the disc and the pad are also measured by using a thermal imaging camera and a pressure mapping system. As a result of the simultaneous measurement of the friction coefficient and squeal amplitude as functions of the velocity, it is found that the onset of the squeal may be predicted from the ${\mu}-v$ curve. It is also found that a non-uniform contact pressure causes instability and, in turn, a squeal. Based on the analysis results, design modifications of the pad are suggested for improved noise characteristics.