• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2441-2445
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• 2009

The effects of Si -doped MgO have been investigated in order to improve the material properties of the MgO protective layer in plasma display panels. A small amount of Si is added to the MgO pellet while the MgO layer is being deposited by using an electron-beam evaporation method. Both the surface characteristics of the protecting layer and the electro-optical properties of 4 in. test panels are investigated, such as XRD patterns, SEM images, firing and sustain voltages, secondary electron emission coefficient($\gamma$), luminance, luminous efficacy and lifetime. The firing and sustain voltage are minimized when Si concentration is 0.038%, where the luminance and luminous efficacy increase up to 17% and 26% compared with that of the pure MgO film, separately, and lifetime also shows good characteristics.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.2
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• pp.74-80
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• 1998

An extensive corrosion study was initiated by galvalume steel sheet manufacturing company to clarify the corrosion behavior of zinc and zinc-alloy coated automotive sheet steel in out panel and electrical application. Since the early 1980's the use of zinc and aluminum alloy coated steel for vehicular corrosion protection has increased drastically. This paper describes the evaluation of formability, weldability and painted corrosion performance of galvalume steel sheet. This paper presents an overview of the program and some initial test results on the weldability, lifetime of the electrode tip shape of the spot welding and corrosion protection. Galvalume steel sheet improved corrosion performance and spot weldability of galvalume steel sheet has no problem for the variation of welding current. And tip lifetime was changed according to the influence of shape.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1283-1288
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• 2008

The FPCB is used as the important component of the sliding mechanism of mobile phones. FPCB have been used as jumper cables(fixed wiring) in various types of circuits because of their flexibility and bending property. The dominant failure mode of the FPCB is open that was caused by fatigue. The fatigue is repeated whenever the sliding is open, so it is a mainly cause of FPCB fatigue. We examined the bending-fatigue lifetime of FPCB. we focused on observing the contact resistance degradation of FPCB of mobile phones according to different test condition of bending strain. As a result, it has proved that lifetime decreased by increasing bending strain.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.8
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• pp.828-832
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• 2015

This study is conducted for the evaluation of corrosion and lifetime prediction of fire extinguishing pipelines in residential buildings. The fire extinguishing pipeline is made of carbon steel. Twenty-four samples were selected among all the fire extinguishing pipelines in a building; the selection was based on specimenspositions, pipeline diameters, and pipeline thickness. Analysis was conducted by using the results of visual inspection, electrochemical potentiodynamic anodic polarization test, pitting depth measurements, and extreme value statistics with the Gumbel distribution. The maximum pitting depth and remaining life were statistically predicted using extreme value statistics. During visual inspection, pitting corrosion was observed in several samples. In addition, extreme value statistics demonstrated that there were several pipelines that were very sensitive to pitting corrosion. However, the pitting corrosion was not critical in all the pipelines; thus, it was necessary to change only those pipelines that were severely corroded.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.7
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• pp.78-84
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• 1998

The problem of autobody corrosion has been addressed over the past decade by the increasing use of zinc and zinc alloy coated steels in automotive application. This paper describes the evaluation of formability, weldability and painted corrosion performance of galvalume steel sheet. This paper presents an overview of the program and some initial test results on the weldability, lifetime of the electrode tip shape of the spot welding and corrosion protection. Galvalume steel sheet improved corrosion performance and spot weldability of galvalume steel sheet was not changed under the influence of the variation of welding current. And tip shape has influenced on the lifetime of tip for galvalume steel sheet.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.407-412
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• 2006

Most of the monopropellant thrusters use catalyst for decomposing hydrazine. The thruster lifetime is determined mainly by catalyst lifetime, which can be investigated by firing tests. For the development of hydrazine decomposition catalyst, Hot-fire test to verify long-life performance of catalyst is required. This study describes the development of test equipment for long duration hot-firing and test/evaluation plan.

• Journal of the Korean Vacuum Society
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• v.8 no.1
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• pp.31-35
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• 1999

In this paper, the lifetime dependence as a function of the line length of Al-1%Si thin film interconnections due to electromigration in semiconductor devices was studied. Al-1%Si thin film interconnections with a pattern of straight type were formed by using a standard photolithography process. The test patterns manufactured have line lengths in the range of 100 to 1600 $mu extrm{m}$. Al-1%Si thin film interconnections with Ti underlayers showed longer lifetime than those without Ti underlayers. Ti underlayers are believed to improve electromigration resistance resulting in a longer lifetime in Al-1%Si thin film interconnections. The dependence of lifetime on the line length in Al-1%Si/Ti thin film interconnections shows a saturation tendency near 800 $\mu\textrm{m}$ line length.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.2
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• pp.46-53
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• 2022

This paper presents the design and manufacture of a Solid State Relay (SSR) life prediction device that can predict the lifetime of an SSR, which is a key component of a glass forming machine. The lifetime of an SSR is over when the current supplied to the relay is overcurrent (20 A or higher), and the operating time is 100,000 h or longer. Therefore, the life prediction device for the SSR was designed using DSP to accurately read the current and temperature values from the current and temperature sensors, respectively. The characteristic test of the manufactured non-contact relay life prediction device confirmed that the current and temperature were safely measured. Thus, the SSR lifetime prediction device developed in this study can be used to predict the lifetime of an SSR attached to a glass forming machine.

• Korean Journal of Materials Research
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• v.27 no.3
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• pp.137-143
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• 2017

Boron-doped diamond (BDD) electrode has an extremely wide potential window in aqueous and non-aqueous electrolytes, very low and stable background current and high resistance to surface fouling due to weak adsorption. These features endow the BDD electrode with potentially wide electrochemical applications, in such areas as wastewater treatment, electrosynthesis and electrochemical sensors. In this study, the characteristics of the BDD electrode were examined by scanning electron microscopy (SEM) and evaluated by accelerated life test. The effects of manufacturing conditions on the BDD electrode were determined and remedies for negative effects were noted in order to improve the electrode lifetime in wastewater treatment. The lifetime of the BDD electrode was influenced by manufacturing conditions, such as surface roughness, seeding method and rate of introduction of gases into the reaction chamber. The results of this study showed that BDD electrodes manufactured using sanding media of different sizes resulted in the most effective electrode lifetime when the particle size of alumina used was from $75{\sim}106{\mu}m$ (#150). Ultrasonic treatment was found to be more effective than polishing treatment in the test of seeding processes. In addition to this, BDD electrodes manufactured by introducing gases at different rates resulted in the most effective electrode lifetime when the introduced gas had a composition of hydrogen gas 94.5 vol.% carbon source gas 1.6 vol.% and boron source gas 3.9 vol.%.

• Journal of Welding and Joining
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• v.25 no.3
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• pp.57-63
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• 2007

Electrochemical migration characteristics of Pb-free solder alloys are quantitatively correlated with corrosion characteristics in harsh environment conditions. In-situ water drop test and corrosion resistance test for Sn-3.0Ag-0.5Cu solder alloys were carried out in NaBr and NaF solutions to obtain the electrochemical migration lifetime and pitting potential, respectively. Sn-3.0Ag-0.5Cu solder alloy shows similar ionization and electrochemical migration behavior with pure Sn because of Ag and Cu do not migrate due to the formation of resistant intermetallic compounds inside solder itself. Electrochemical migration lifetime in NaBr is longer than in NaF, which seems to be closely related to higher pitting potential in NaBr than NaF solution. Therefore, it was revealed that electrochemical migration lifetime of Sn-3.0Ag-0.5Cu solder alloys showed good correlation to the corrosion resistance, and also the initial ionization step at anode side is believed to be the rate-determining step during electrochemical migration of Pb-free solders in these environments.