• Title/Summary/Keyword: Cold-hot impact test

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A Studies on the Characteristics of Reliability Test by Automotive Touch Screen Silver Pastes (자동차 터치스크린용 실버페이스트 종류에 따른 신뢰성 테스트 특성 연구)

  • Kim, Jung-won;Choi, Ung-se
    • Journal of IKEEE
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    • v.20 no.2
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    • pp.205-208
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    • 2016
  • In this paper, different types of touch screen silver pastes for bonding in conductive pattern formed over the ito film by bonding each sample of 5 was dried. The dry conditions, the oxidation of the ito film is a condition that does not occur. Reliability testing constant temp and humidity, cold-hot impact test is in progress. Each test will check the status of five sheets conductive pattern bonding. Conductive pattern bonding, after each 240,480,615 hours to check the status of silver pattern bonding. Reliability testing these through different silver pastes can see that the change in the adhesion and conductivity deterioration of the quality can be prevented, and reliability testing low temperature curing from the surface of silver pastes that can come as soon as the discoloration was unknown.

Weldability of HY type High Strength-Toughness Steel (HY계 고강도 고인성강의 용접성)

  • ;;;Ahn, S. K.;Shim, I. O.
    • Journal of Welding and Joining
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    • v.13 no.3
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    • pp.65-76
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    • 1995
  • Weldability of DS100 and HY type high strength-toughness steel plates, tentatively produced as domestic production, was investigated. DS100 and DS130A had nearly same hardenability in HAZ in spite of its difference in Ceq. Based upon the y-groove test results, cold cracking susceptibility of DS130 was superior to that of DS100 because of its lower hydrogen level in weld metal. Solidification cracking tested by the Trans-Varestraint test was occured in all of the weld metals, and its susceptibility was high in the row of DS100, DS130A and DS130B. However, no liquation cracking and ductility-dip cracking tested by the Longi-Varestraint test with 6.0% augmented strain were detected in base metal and reheated weld metal. Toughness in the GMA welding joint was satisfied with the relative Mill Spec, even though welded joint of DS100 had relatively low impact energy especially at the weld metal.

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A Study on the Toughness of Die Steel Coated with VC (vanadium carbide) by Immersing in Molten Borax Bath (용융염 침적법에 의한 VC Coating 금형강의 인성에 관한 연구)

  • Lee, B.K.;Nam, T.W.
    • Journal of the Korean Society for Heat Treatment
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    • v.6 no.2
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    • pp.59-69
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    • 1993
  • Bending fracture strength test and impact strength test were made for VC coated die steels treated by immersing in molten borax bath and for hardened steels which were quenched and tempered, in order to clarify the effect of VC coating at $1000^{\circ}C$. The material used in this investigation was representative cold and hot work die steels STD11, STD61. The results obtained are as follows. 1) The bending fracture strength of VC coated die steel (STD11, STD61) was lessened with increasing the thickness of the VC coated layer. 2) With increasing the immersing time (imcreasing the thickness of the VC coated layer) the maximum hardness was obtained at 480 minutes holding, after that holding time hardness was decreased. 3) The impact strength of the VC coated die steel was not decreased. In the casse of STD11, it was higher than that of the quenched condition especially at low tempering temperature, and vice versa at high tempering temperature. However in the case of STD61 shows the result to the contrary.

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A Study on Characteristics of Methane Emissions from Gasoline Passenger Cars (휘발유 자동차의 메탄(CH4) 배출특성에 관한 연구)

  • Jeon M.S.;Ryu J.H.;Lyu Y.S.;Kim J.C.;Lim C.S.;Kim D.W.;Jeong S.W.;Cho S.Y.
    • Journal of Korean Society for Atmospheric Environment
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    • v.21 no.6
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    • pp.649-655
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    • 2005
  • Automotive exhaust is suspected to be one of the main reasons of the rapid increase in greenhouse effect gases in ambient air. Although methane emissions are generally orders of magnitude lower than emissions of $CO_{2}$, the global warming potential (GWP) of methane is greater than that of $CO_{2}$. The environmental impact of methane emissions from vehicles is negligible and is likely to remain so for the foreseeable future. In this study, in order to investigate greenhouse gas emission characteristics from gasoline passenger cars, 20 vehicles were tested on the chassis dynamometer and methane emissions were measured. The emission characteristics by model year, mileage, vehicle speed were discussed. Test mode is CVS-15 mode that have been used to regulate for light-duty vehicle in Korea. It was found that $CH_{4}$ emissions showed higher for cold start, old model year and long mileage than hot start, new model year and short mileage, respectively. These results were compared with IPCC emission factors and the overall our results were anticipated to contribute for domestic greenhouse gas emissions calculation.

Why Do Mobile Device Users Take a Risky Behavior?: Focusing on Model of the Determinants of Risk Behavior (모바일 기기 사용자는 왜 정보보호에 위험한 행동을 하는가? : 위험행동 결정요인 모델을 중심으로)

  • Kim, Jongki;Kim, Jiyun
    • The Journal of Information Systems
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    • v.28 no.2
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    • pp.129-152
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    • 2019
  • Purpose The purpose of this study is to empirically identify the risky behavior of mobile device users using the Internet of Things on a situational perspective. Design/methodology/approach This study made a design of the research model based on model of the determinants of risk behavior. Data were collected through a survey including hypothetical scenario. SmartPLS 2.0 was used for the structural model analysis and t-test was conducted to compare the between normal and situational behavior. Findings The results were as follows. First, the central roles of risk propriety and risk perception were verified empirically. Second, we identified the role of locus of control as a new factor of impact on risky behavior. Third, mobile risk propensity has been shown to increase risk perception. Fouth, it has been shown that risk perception does not directly affect risky behavior and reduce the relationship between mobile risk propensity and risk behavior. According to the empirical analysis result, Determinants of risk behavior for mobile users were identified based on a theoretical framework. And it raised the need to pay attention to the impact of locus of control on risk behavior in the IS security field. It provided direction to the approach to risky behavior of mobile device users. In addition, this study confirmed that there was a possibility of taking risky behavior in the actual decision-making.

Effect of NbC Carbide Addition on Mechanical Properties of Matrix-Type Cold-Work Tool Steel (매트릭스(matrix)형 냉간금형강의 기계적 특성에 미치는 NbC 탄화물 첨가의 영향)

  • Kang, Jun-Yun;Kim, Hoyoung;Son, Dongmin;Lee, Jae-Jin;Yun, Hyo Yun;Lee, Tae-Ho;Park, Seong-Jun;Park, Soon Keun
    • Journal of the Korean Society for Heat Treatment
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    • v.28 no.5
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    • pp.239-249
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    • 2015
  • Various amount of NbC carbide was intentionally formed in a matrix-type cold-work tool steel by controlled amount of Nb and C addition. And the effect of NbC addition on the mechanical properties was investigated. Four alloys with different Nb and C contents were cast by vacuum induction melting, then hot forging and spheroidizing annealing were conducted. The machinability of the annealed specimens was examined with 3 different cutting tools. And tensile tests at room temperature were conducted. After quenching and tempering, hardness and impact toughness were measured, while wear resistance was evaluated by disk-on-plate type wear test. The increasing amount of NbC addition resulted in degraded machinability with increased strength, whereas the absence of NbC also led to poor machinability due to high toughness. After quenching and tempering, the additional NbC improved wear resistance with increasing hardness, whereas it deteriorated impact toughness. Therefore, it could be found that a moderate addition of NbC was desirable for the balanced combination of mechanical properties.

Suitable Conditions of Producing the LVL from Pitch Pine and its Paint Film Durability (리기다소나무 단판적층재(單板積層材)의 제조조건(製造條件)에 따른 물리적성질(物理的性質) 및 도장성능(塗裝性能))

  • Park, Sang-Bum;Kong, Young-To;Jo, Jae-Myeong
    • Journal of the Korean Wood Science and Technology
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    • v.17 no.1
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    • pp.3-11
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    • 1989
  • This study was carried out to investigate the physical and mechanical properties. durability of adhesive bond and paint film for the basic data which were required to determine the suitability as a raw material for furniture the laminated veneer lumber (LVL) with pitch pine (Pinus rigida Mill). The results obtained were as follows; 1) The proper pressing time for making the LVL was over 45 second per milimeter of LVL thickness. 2) The bending strength of the LVL was lower than that of the solid wood but the compressive strength of the LVL was similar to that of the solid wood. The strength increased with the decrease of veneer thickness. 3) The impact bending absorbed energy of the LVL was 0 to 0.3 kg.m/$cm^2$ in the direction of parallel to the grain. The energy of the LVL was lower than that of the solid wood (0.68 kg.m/$cm^2$). 4) In warm water soaking and cold-dry tests, delamination of adhered layers surface crack, swelling, and color change were not found when the hot pressing time was over 45 second per milimeter of LVL thickness. As a result of soak under vacuum test shrinkage in the direction of parallel to the grain was about -1.0 percent and. was about 3.0 percent in the direction of the perpendicular to the grain. 6) The film cacks on the LVL's surface after the wet and cold-dry test were not found at all. 7) In the use of the LVL for interior decoration it was considered that the surface of the LVL be overlaid crossly with fancy veneers of birch and paulownia, etc. This cross overlayirg methods have resulted in few cracks on the fancy veneer.

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