• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.415-420
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• 2000

This paper describes a part of the results obtained in the process of the development of thin sound isolation sheets filled mineral compound powder with PVC. The raw materials used are pyrophillite, pottery stone and graphite. The physical properties such as the crystal structures, compositions, and specific gravities, etc. of raw materials are analyzed and discussed from a point of view of sound isolation material. From the analysis of experimental results, the particle size and the additive amount of mineral compound powder for manufacturing sample isolation sheets are decided. The resistant capability against fire of sound isolation sheets including mechanical, thermal and physical properties is tested. The transmission loss measuremenst of sound isolation sheets are performed using two-microphone method in an impedance tube. It is shown that the sound isolation capability of thin sheets has an excellent performance in excess of the object of development.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.23-26
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• 2002

In this paper, We have studied the CMP (chemical mechanical polishing) characteristics of diluted slurry by adding of raw alumina abrasive and annealed alumina abrasive. As a experimental results, we obtained the comparable slurry characteristics compared with original silica slurry in the view point of high removal rate and low non-uniformity. Therefore, we can reduce the cost of consumables(COC) of CMP process for ULSI applications.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.6 no.2
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• pp.93-102
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• 1994

It is the goal of this study to provide the essential data for design and operation of optimum water supply system. Experimental and theoretical analyses have been conducted for various parameters, for example, volume and air percent of pressurizing tank, pump speed and pressure range inside tank, etc. Pressure inside tank with time, flow rate, energy consumption rate and pump operation time have been obtained for design and operating parameters to optimize the components and to establish the operating method of system, and therefore to contribute to the development of technology from a point of view of the improvement of quality, the enhancement of system efficiency and the reduction of construction cost.

• Korean Institute of Interior Design Journal
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• no.5
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• pp.37-44
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• 1995

Memphis originated from Radicalism in Italy came into being in 1981 as a experimental design group. Basically Memphis represented changed concept of design and the task of the designer by innovative design with unusual shapes and colors. What Memphis intended to demon-strate is the diversity of expression of design creativity and possibilities of new stimuli. As a result, Memphis has shown ways of redefining the field of design. In the 1990, the diversity of design movenment reflects the plualism of fragmented, specialized society. Design is faced with new task. It must do more than merely de-fine an object and its function. So from this point of view, this study interpretates ideas of Memphis design theory and attitude.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.2
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• pp.155-160
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• 1999

Recently, the study on mix design of lightweight concrete using the polystyrene foam balls is put into practice from the viewpoint to grade up the quality of concrete and recyclable usage of industrial by products. Polystyrene aggregate concrete, PAC, can be used as structural concrete in low strength application. For instance, PAC could be used in the middle part of sandwich panel where stresses are generally low and in the case of grid-type reinforcement where it does not need high bond strength but little compressive strength to resist the pressure of transverse reinforcement. From this point of view, the authors discussed the influence of fluidity and compressive strength of concrete by the difference of the volume percentage of polystyrene foam balls and water cement ratio.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.5 no.2
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• pp.91-97
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• 1976

This study was concerned with performance of 2 types of black painted solar air heaters, one is finned type better, the other is mesh type. The performance test of heaters was made under the different operating conditions during winter season of December in Seoul area. It was analized and discussed by comparing the overall efficiency of 2 solar heaters at the same mass flow rate and ambient temperature. Experimental results show that finned type solar heater is better than mesh type from the point of view of design and heat removal efficiency. Finned-type solar air heater supplies hot air up to 30 degree centigrade above ambient temperature with an overall efficiency of 47 percent whilemesh type was 44 percent.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.378-381
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• 2003

Efficient development of method on a performance evaluation for machine tools has been regarded as the most important work for accuracy and quality enhancement to every user and manufacturer. A evaluation method of accuracy for machine tools has been studied recently according to the rapid increase of interest in precision machine tools. To this point of view, the circular interpolation test of machine tools is recognized as the most useful method to distinguish a dynamic accuracy of NC machine tools by ISO and ANSI/ASME, etc. In this paper, we have studied and developed the form measurement system with grid encoder to analyse the final accuracy of NC machine tools. we have analyzed the servo system error and geometric error of NC machine tools through measuring a dynamic error signal by this system. and then we verified the experimental result and enhanced the reliability by means of comparing the characteristics of the developed system with the kinematic ball-bar system.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.404-411
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• 2007

Reinforced roadbeds are valued from the point of view of maintenance as well as enhanced mechanical capacity. They support more train load and less transmit to the sub-layers than general roadbeds. Also, the lateral sloping surface of the reinforced roadbed and its low permeability, achieved by the controlled compaction, increase drainage capability and prevent the softening of sub-layers. In the study, a series of cross-hole tests was performed to observe the temporal changes in the stiffness of reinforced roadbeds, if any, due to the cyclic loading of trains and alternating rainy and frozen seasons at Pyeong-taek experimental site. The three types of reinforced roadbed materials are slag, crushed stones, and soils, and the thickness of all the reinforced roadbeds is 0.8m. The stiffness of the slag and soil reinforced roadbeds was not changed or slightly decreased. The stiffness of the crushed stone was somewhat increased and is inferred to being densified close to surface.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.11a
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• pp.43-46
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• 2006

The Hwangtoh is one of the traditional construction material used in wall, plastering material, and ondol (Korean underfloor heating system) with stone and wood. It is an important greenness material and it has much advantages such as; high storage of heat, auto-purification, antibiotic ability, and emission of far infrared rays. But, it is not developed and not used in modern construction because of its low strength and properties of dry shrinkage crack. According to the recent researches and studies, it is evaluated for natural pozzolanic material like flyash or pozzolan. It's possibility on construction material is high because it's chemical and mineralogical proportion is like as Metakaolin and Kaolinite. In this point of view, this study aims to analyze the physical properties on Hwangtoh mortar through an experiment with various activation condition of Hwangtoh, which is natural pozzolanic material, for the purpose of increase the using possibility in construction material.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.6
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• pp.1320-1326
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• 1988

This paper deals with the behavior of surface crack growth and the characteristics of surface micro-crack distribution under creep and creep-fatigue with 1 min. and 10 min. of load holding times at 593.deg.C, in air. The test specimen is a plate type with a small artificial defect of type 304 the small defect has been carried out by the surface replica method and optical microphotography. The experimental results have been interpreted from the view-point of fracture mechanics. It can be concluded that the longer the hold time the longer the total life time. Most of surface micro-cracks initiate at grain boundaries before the specimen reaches 20% of its total life time, a few of them lead to fracture by coalescence with the main crack.