• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.73-77
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• 1997

This paper describes the analysis of measuring error of on the machine measuring(OMM) system which can directly measure the three dimensional machined free surface dimension using scanning probe on milling machine. 21 inch TV shadow mask mould was measured using PTP(point to point)measurement algorithm at pallet clamped and unclamped state on OMM system, and using coordinate measuring machine(CMM) one after another. The OMM system was evaluated probe error, stylus contact error, center shift error, repeatability and so on. Consequencely, the conclusion derived that elastic displacement of pallet had effect on measuring error mainly, and pallet design and setup method would be important.

• Structural Engineering and Mechanics
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• v.4 no.3
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• pp.313-329
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• 1996

A mathematical model of a cable as a system of interacting wires with interwire friction taken into account is presented in this paper. The effect of friction forces and the interwire slip on the mechanical properties of tension cables is investigated. It is shown that the slip occurs due to the twisting and bending deformations of wires, and it occurs in the form of micro-slips at the contact patches and macro-slips along the cable. The latter slipping starts near the terminals and propagates towards the middle of the cable with the increase of tension, and its propagation is proportional to the load. As the result of dry friction, the load-elongation characteristics of the cable become quadratic. The energy losses during the extension are shown to be proportional to the cube of the load and in inverse proportion to the friction force, a result qualitatively similar to that for lap joints. Presented examples show that the model is in qualitative agreement with the known experimental data.

• Transactions of Materials Processing
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• v.22 no.2
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• pp.101-107
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• 2013

The heat transfer characteristics between die and sheet and die and coolant are important parameters in hot press forming process. The determination of the quenching time that guarantees full martensitic transformation requires proper understanding of these heat transfer characteristics. The contact area changes drastically during the quenching process due to volume changes of both die and sheet by temperature drop as well as phase transformation. Several types of modeling techniques are tested in order to select the most suitable. The effect of quenching time as well as die heat conductivity on martensitic transformation is investigated and predictions are compared to experimental results.

• Journal of Environmental Health Sciences
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• v.32 no.4 s.91
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• pp.282-291
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• 2006

This study investigated the inactivation of the total coliform, an indicator organism in chlorine and chlorine in order to control microbial regrowth for water distribution systems and select an appropriate disinfection strategy for drinking water systems. The disinfection effects of chlorine and chlorine dioxide with regard to the dosage of disinfectant, contact time and DOC was investigated experimentally. In spite of the consistency of chlorine residuals at approximately 0.2 mg/l, bacteria regrowth was detected in the distribution system and it was confirmed by the scanning electron microscope results. The influence of organic carbon change on the killing effect of chlorine dioxide was strong.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1631-1633
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• 2008

We demonstrate 4-in QVGA active-matrix electrophoretic display based on ink-jet printed organic transistors on glass substrates. Our TFT array had a bottom-gate, bottom-contact device architecture. The organic semiconductor and gate dielectric were solution processed. The field-effect mobility of the printed devices, calculated in the saturation region, was $0.1{\sim}0.3cm^2/Vs$ at Vg=-20 V.

• Journal of Drive and Control
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• v.16 no.4
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• pp.9-15
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• 2019

Bucket trajectory is crucial regarding precision work with an excavator. In general, the bucket trajectory deviation is determined by the machining deviation of the frame, driving deviation of the driving hydraulic cylinder, clearance in the joints, and deformation of the structure. This paper investigated the relationship between the respective clearance in joints and the trajectory deviation of the bucket at the finishing work of the ditching for a 20-ton excavator. As a result, the larger the clearance, the larger deviation is increased at trajectory. However, it was found that the deviation of the rotation angle and displacement of the bucket was limited and the size of clearance does not affect closely on the contact angle of the pin shaft.

• Food Industry And Nutrition
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• v.11 no.3
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• pp.44-48
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• 2006

본 연구는 옻(Rhus verniciflua)에 대한 국산 미생물 발효차 폴리 페놀물질 인 theaflavin(TF)과 thearubigin(TR)의 항알레르기 효과를 조사하였다. HPLC, column chromatography 및 TLC로 이용하여, 한국 원주산, 일본산 및 중국산 락커(lacquer)로부터 아주 강한 알레르기를 유발하는 long chain alkylphenol을 함유하는 crude urushiol 성분을 분리하였다. 고분자 이중 및 삼중불포화물질의 함량은 중국산 라커의 crude urushiol에 가장 많이 포함되어 있었다. 중국산 라커의 crude urushiol에서 유발되는 접촉성 알레르기 피부염 발생은 5%농도에서 한국산이나 일본산 라커의 시료보다 높았으며, TF 및 TR를 처리한 모든 농도에서 접촉성 알레르기 피부염의 유의적인 감소를 나타내었다. 이들 결과로부터 발효차의 폴리페놀성 TF와 TR은 옻의 접촉성 피부염에 대한 유의적인 항알레르기 효과를 나타내었다.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.245-252
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• 2000

Model tests on free standing pile groups and piled footings with varying a pile spacing in two layered soils are carried out. The influence of pile cap on the behaviors of end bearing pile groups is analyzed by comparing the bearing behavior in piled footings with those in a single pile, a shallow footing(cap alone) and free standing pile groups. From the test results, it is found that the bearing characteristics of cap-soil-pile system are related with load levels and pile spacings. Before yield, the bearing resistance by cap is not fully mobilized, however, as the applied load increases, the bearing resistance of cap approaches to that of cap alone and settlement hardening occurs after yield due to the compaction caused by the contact pressure between cap and soil. By the cap-soil-pile interaction, shaft friction and point resistance of piles considerably increase with dependency of pile spacings. In two layered soil, the increasing effect of dilatancy in dense sandy soil adjacent to pile tips, increases the point resistance of pile.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1291-1298
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• 2005

Shotcrete for the support of tunnel can contact with groundwater. The hazardous components in the groundwater cause the corrosion of shotcrete. Also, the hazardous components may deteriorate the engineering properties of shotcrete, such as compressive strength, bond strength, and flexural strength. The more the effect of the hazardous components on the shotcrete may increase, the more the stability of tunnel structure may decrease. It was analyzed to find the hazardous components in the ground water. The uniaxial compressive strength test, XRD, SEM were conducted to evaluate the durability and corrosion of shotcrete. These tests were performed on shotcrete specimens at 2, 4, 8, and 16 weeks. The specimens were immersed in various chemical solutions including hazardous components after the specimens were made at the construction site.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1135-1138
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• 2006

By ink-jet printing method, organic thin-film transistors (OTFTs) having soluble 6,13-bis (triisopropylsilylethynyl) pentacene (TIPS pentacene) as an active material were fabricated. The TIPS pentacene solution was made with chlorobenzene and anisole. The solutions were printed on poly (4-vinylphenol) (PVP) dielectric layers and source/drain electrodes by piezo-type heads for bottom contact OTFTs. The dielectric layers had untreated or HMDS-treated conditions. The chlorobenzene device showed the highest field effect mobility of $0.016\;cm^2/Vs$ and the anisole HMDS-treated device shows the highest $I_{on}/I_{off}$ ratio of $10^5$.