• Journal of the Microelectronics and Packaging Society
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• v.17 no.4
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• pp.11-17
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• 2010

The electromigration phenomenon in lead-free flip-chip solder joint has been one of the serious problems. To understand the mechanism of this phenomenon, the crystallographic orientation of Sn grain in the Sn-Ag-Cu solder bump has been analyzed. Different time to failure and different microstructural changes were observed in the all test vehicle and bumps, respectively. Fast failure and serious dissolution of Cu electrode was observed when the c-axis of Sn grain parallel to electron flow. On the contrary of this, slight microstructural changes were observed when the c-axis of Sn perpendicular to electron flow. In addition, underfill could enhance the electromigration reliability to prevent the deformation of solder bump during EM test.

• Journal of environmental and Sanitary engineering
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• v.19 no.3 s.53
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• pp.65-70
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• 2004

This study was peformed to survey and evaluate contents of Pb and Cd in colored plastic kitchenwares by Korea Food Sanitation Act. The tested samples were 160 products(32 PE, 65 PP, 10 PS, 18 ABS and 35 MF) in a local market. The Pb and Cd contents range in the samples were $ND\~357.1mg/kg\;and\;ND\~376.6mg/kg$. Pb contents in 6 samples(1 PE, 1 PP, 2 PS and 2 MF) and Cd contents of 2 samples(1 PE and 1 ABS) were above the legal limits. Among the illegal smples, Pb contents were 140.8mg/kg, 283.4mg/kg, 134.0mg/kg, 329.2mg/kg, 357.1mg/kg and 218.3mg/kg, respectively and Cd contents were 123.1mg/kg and 376.6mg/kg. Pb and Cd in various food simulants were not detected in migration test for illegal samples. Simulants were tested at $25^{\circ}C\;and\;60^{\circ}C$ for n-heptane and $4\%$ acetic acid, and $60^{\circ}C\;and\;95^{\circ}C$ for water.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.6
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• pp.37-45
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• 2015

In this experimental study, effect of milled glass fibers was investigated on corrosion resistance of PSC grout mortar. In order to check whether the mortar mixture with milled glass fibers satisfy the required properties as a PSC grout, time of flow, bleeding and compressive strength measured. The corrosion resistance were investigated through chloride ion migration test, mortar absorption test and surface resistivity measurement. It is confirmed that all proportions with milled glass fibers have better corrosion resistance than that with only OPC binder. Time of flow was reduced but the bleeding was increased to unacceptable level by using milled glass fibers. Consequently, the mix proportion with milled glass fibers for a PSC grout should be modified to have lower water/binder ratio.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.1
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• pp.8-16
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• 2017

Structural integrity of solid rocket depends on the residual reactions between constituents of its composition(post cure, migration etc.), the oxygen(or anti-oxydent) in the free volume and humidity (desiccant) under the perfect sealed condition. Mechanical Properties of composite solid propellant arising from those factors are very complex. Moreover the propulsion are faced with thermal loads from diurnal & seasonal cycle till firing. In this study, the fast evaluation method of long term mechanical properties is suggested based on Thermo-Rheological Simplicity from curing oven to cool-down stage in view point of thermal stabilization. For this subject, endurance tester having temperature control capability are devised. From the results from incremental load and strain, non-linear characteristics are discussed.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.3
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• pp.247-256
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• 2014

Recently, camera and RADAR are used for more effective and accurate observation of the bird migration. In recent years, many researches on the bird migration using RADAR are undertaking and in active, thus causes the advent of "RADAR ornithology" as a new academic field. Due to the lack of accessibility, economic feasibility and mobility of weather RADAR, airport searching RADAR and tracking RADAR, Nowadays, a marine RADAR is widely used for a bird observation. In this paper, we deals with a study on development of a remote bird observation system using marine FMCW RADAR, which monitors, records and analyzes bird movement by RADAR image processing and target recognition technology. Also, we conduct first test and second test for availability of the developed system, and verify the system to apply in bird observation domain. Consequently, we figured problems out, and correct the problems to improve the system. The developed system can apply in other domains such as environment evaluation. In the future, the system needs to improve accuracy of statistics and to track migration route of bird.

• Journal of the Korea Institute of Building Construction
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• v.16 no.4
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• pp.321-329
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• 2016

The use of ternary blended cement consisting of Portland cement, granulated blast-furnace slag (GGBFS) and fly ash has been on the rise to improve marine concrete structure's resistance to chloride attack. Therefore, this study attempted to investigate changes in chloride attack resistibility of concrete through NT Build 492-based chloride migration experiments and test of concrete's ability to resist chloride ion penetration under ASTM C 1202(KS F 2271) when 1.5-2.0% of alkali-sulfate activator (modified alkali sulfate type) was added to the ternary blended cement mixtures (40% ordinary Portland cement + 40% GGBFS + 20% fly ash). Then, the results found the followings: Even though the slump for the plain concrete slightly declined depending on the use of the alkali-sulfate activator, compressive strength from day 2 to day 7 improved by 17-42%. In addition, the coefficient from non-steady-state migration experiments for the plain concrete measured at day 28 decreased by 36-56% depending on the use of alkali-sulfate. Furthermore, total charge passed according to the test for electrical indication of concrete's ability to resist chloride ion penetration decreased by 33-62% at day 7 and by 31-48% at day 28. As confirmed in previous studies, reactivity in the GGBFS and fly ash improved because of alkali activation. As a result, concrete strength increased due to reduced total porosity.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.28 no.1
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• pp.15-21
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• 2022

The purpose of our study was to investigate the migration level of lead (Pb), cadmium (Cd), and barium (Ba) from glassware into a food simulant and to evaluate the exposure of each element. The test articles were glassware, including tableware, pots, and other containers. Pb, Cd, and Ba were analysed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The analytical performance of the method was validated in terms of its linearity, limit of detection (LOD), limit of quantification (LOQ), recovery, precision, and uncertainty. The monitoring was performed for 110 samples such as glass cups, containers, pots, and bottles. a food simulant. Migration test was conducted at 25? for 24 hours in a dark place using 4% acetic acid as a food simulant. Based on the data; exposure assessment was carried out to compare the estimated daily intake (EDI) to the human safety criteria. The risk levels of Pb and Ba determined in this study were approximately 1.9% and 0.3% of the provisional tolerable weekly intake (PTWI) and tolerable daily intake (TDI) value, respectively, thereby indicating a low exposure to the population.

• Tunnel and Underground Space
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• v.34 no.2
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• pp.89-103
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• 2024

In the disposal environment, gases can be generated at the interface between canister and buffer due to various factors such as anaerobic corrosion, radiolysis, and microbial degradation. If the gas generation rate exceeds the diffusion rate, the gas within the buffer may compress, resulting in physical damage to the buffer due to the increased pore pressure. In particular, the rapid movement of gases, known as gas breakthroughs, through the dilatancy pathway formed during this process may lead to releasing radionuclide. Therefore, understanding these gas generation and movement mechanism is essential for the safety assessment of the disposal systems. In this study, an experimental apparatus for investigating gas migration within buffer was constructed based on a literature review. Subsequently, a gas injection experiment was conducted on a compacted bentonite block made of Bentonile WRK (Clariant Ltd.) powder. The results clearly demonstrated a sharp increase in stress and pressure typically observed at the onset of gas breakthrough within the buffer. Additionally, the range of stresses induced by the swelling phenomenon of the buffer, was 4.7 to 9.1 MPa. The apparent gas entry pressure was determined to be approximately 7.8 MPa. The equipment established in this study is expected to be utilized for various experiments aimed at building a database on the initial properties of buffer and the conditions during gas injection, contributing to understanding the gas migration phenomena.

• Journal of Industrial Technology
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• v.28 no.B
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• pp.65-69
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• 2008

The tailings piled in abandoned mines are well-known potential sources of soil contamination. Hydrated limes were applied as cementing materials to solidify heavy metal contaminated tailings for the purpose of reducing their toxicity and migration rates. The optimum mixing ratio of tailings, hydrated lime, and water was determined through a preliminary test. The mixtures of mine tailings and hydrated lime solidified through pozzolanic reaction were tested for their durability against repeated freezing and thawing processes. After repeated freezing and thawing, the uniaxial compressive strengths of all the solidified mixture specimens decreased in comparison with those before test but still higher than $3.5kgf/cm^2$, the standard recommended for land reclamation solids by EPA(Environmental Protection Agency), which suggested that hydrated lime be a potential material to treat the abandoned mine tailings for the environmental purpose.

• Biomolecules & Therapeutics
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• v.6 no.3
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• pp.269-275
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• 1998

These studies were conducted to investigate the antiinflammatory effects and the mechanism of action of natural products. We used the methods of "carrageenan induced foot edema" , "PAF (platelet activating factor) induced foot edema" , "inhibition test of vascular permeability" , "inhibition test of white blood cell migration" , "formation of granuloma" and "adjuvant induced arthritis" to examine the antiinflammatory erects of Angelica gigas, Ledebouriella seseloides, Ginkgo biloba and Bamboo salt (Jukyom). The oral administration of the water extract of Angelica gigantis radix, the methanolic extract of Ginkgo folium and the aqueous solution of Bamboo salt showed antiinflammatory effect on carrageenan and PAF induced foot edema in SD rat at a dose of 1 g/kg. The same administration of methanolic extract of Ginkgo folium also inhibited the vascular permeability in mice. The aqueous solution of Bamboo salt inhibited the formation of ganuloma in SD rats at a oral dose of 1 g/kg. Angelica gigantis radix seems to have antiinflammatory effect by inhibition of PAF.