• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.1 s.20
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• pp.39-48
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• 2006

A laboratory investigation was performed to estimate the moduli values of asphalt concrete mixture due to various sinusoidal loadings in compression and tension. Total five modes of loading were used under five testing temperatures of 32, 50, 68, 86, and $104^{\circ}F$ (0, 10, 20, 30, and $40^{\circ}C$); repeated compressive haversine loading with rest period, repeated tensile haversine loading with rest period, cyclic compressive loading, cyclic tensile loading, and alternate tensile-compressive loadings. The test results showed that, due to the repeated haversine loading with rest period, asphalt concrete demonstrated similar moduli in tension and compression at low temperatures,(0 and $10^{\circ}C$) while those moduli were different at high temperatures (20, 30, and $40^{\circ}C$). At high temperatures the compressive moduli were always higher than the tensile moduli. The uniaxial tensile moduli were higher than indirect tensile moduli at low temperatures. However, those moduli were similar at high temperatures. In uniaxial cyclic tension, compression, and alternate tension-compression tests, compressive moduli were higher than tensile and alternate tensile-compressive moduli throughout the temperatures. Generally, the moduli from the repeated haversine loading with rest period were always lower than those from the cyclic sinusoidal loading. The difference in moduli from the repeated haversine loading with rest period and cyclic sinusoidal loading becomes more significant as the temperature decreases.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.2 s.35
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• pp.121-128
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• 2005

Solder joints in microelectronic devices are frequently operated at an elevated temperature in service. They also experience plastic deformation caused by temperature excursion and difference in thermal expansion coefficients. Deformed solders can go through a recovery and recrystallization process at an elevated temperature, which would alter their microstructure and mechanical properties. In this study, to predict the changes in mechanical properties of Pb-free solder joints at high temperatures, the high temperature microhardness of several Pb-free and composite solders was measured as a function of temperature, deformation, and annealing condition. Solder alleys investigated include pure Sn, Sn-0.7Cu, Sn-3.5Ag, Sn-3.8Ag-0.7Cu, Sn-2.8Ag-7.0Cu (composite), and Sn-2.7Ag-4.9Cu-2.9Ni (composite). Numbers are all in wt.$\%$ unless specified otherwise. Solder pellets were cast at two cooling rates (0.4 and $7^{\circ}C$/s). The pellets were compressively deformed by $30\%$ and $50\%$ and annealed at $150^{\circ}C$ for 2 days. The microhardness was measured as a function of indentation temperature from 25 to $130^{\circ}C$. Their microstructure was also evaluated to correlate with the changes in microhardness.

• Journal of Bio-Environment Control
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• v.27 no.3
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• pp.213-221
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• 2018

We analyzed the skin coloration and anthocyanin composition of 'Kyoho' and 'Heukboseok' grape berries to determine the cause of poor coloring in 'Kyoho' berry skins under high temperature (HT) at veraison. Although the skin coloration inhibited in both 'Kyoho' and 'Heukboseok' berries under HT for 30 days from veraison, the total anthocyanin content in 'Heukboseok' berry skins increased to the level of control after the end of temperature treatment, but 'Kyoho' did not increase. Malvidin derivatives were most significantly reduced in 'Kyoho' berry skins, followed by those of delphinidin and petunidin. Among individual anthocyanins, diglucosides and acylated malvidin derivatives were most decreased in 'Kyoho' berry skins. Acylated and tri-hydroxylated anthocyanins were reduced more than those of non-acylated and dihydroxylated, respectively. All different types of anthocyanin components in 'Kyoho' berry skins decreased by HT, and they were similar to that of total anthocyanin. In 'Heukboseok' berry skins, accumulations of all different types of anthocyanins were inhibited by HT, and increased to the level of control after the end of the treatment. These results suggest that the poor coloration of 'Kyoho' under HT at veraison was not caused by the decrease of specific anthocyanins but because the whole anthocyanin biosynthesis was suppressed by HT.

• Polymer(Korea)
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• v.36 no.2
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• pp.169-176
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• 2012

Based on our experience in developing resistive humidity sensor, interdigital gold electrodes with different fingers and gaps have been fabricated on a glass epoxy (GE) substrate using screen printing techniques. The basic structure of the electrode consisted of a 3-, 4- and 5-fingers with gaps of 310 and 460 ${\mu}m$. Gold electrode/GE was prepared by first printing silver nanopaste, followed by consecutive electroless plating of Cu, Ni and then Au. Copolymer of [2-(methacryloyloxy)ethyl] dimethyl benzyl ammonium chloride (MDBAC) and methyl methacrylate (MMA) was used as a humidity-sensing polyelectrolyte, which was fabricated by a screen printing method on the Au electrode/GE substrate. The flexible humidity sensor showed acceptable linearity between logarithmic impedance and relative humidity in the range of 20-95%RH, low hysteresis of 1.5%RH, good response and recovery time of 75 sec at 1 V, 1 kHz, and $25^{\circ}C$. Electrode construction had a significant influence on the humidity-sensing characteristics of polymeric humidity sensors. The activation energy between electrode and ion conducting polyelectrolyte plays an important role in explaining the differences of humidity sensing characteristics such as temperature dependence, sensitivity, linearity and hysteresis.

• Korean Journal of Microbiology
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• v.25 no.3
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• pp.221-228
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• 1987

The extracellular adenine deaminase from Nocardioides sp. J-275L was purified by the following techniques: ammonium sulfate fractionation, DEAE-Cellulose, DEAE-Sephadex A-50 column chromatography, and Sephacryl S-200 superfine gel filtration. The enzyme was partially purified about 3889.5-fold with about 5.2% yield by these procedures. The molecular weight of the enzyme was 39,000 by a calibrated Sephacryl S-200 superfine column chromatography. The enzyme was stable at pH 7.5 and up to $40^{\circ}C$. Glycerol was effective on the stabilization of the enzyme during storage. The optimum pH and temperature of the enzyme were around pH 7.5 and $40^{\circ}C$, respectively. The apparent Michaelis constant Km of the enzyme for adenine was $7.4\times 10^{-5}$M. The purine analogues, 6-chloropurine, 2,6-diaminopurine, 6-bromopurine, 4-aminopyrazolo [3.4-d]pyrimidine, and 8-azaadenine were substrates for the enzyme. 6-Dimethylaminopurine was a competitive inhibitor of the enzyme. The enzyme was inhibited by 1mM of $Cu^{2+}, Fe^{3+}, Pb^{2+}, Hg^{2+}$, and $Ag^{+}$, and 1mM of $\alpha$,$\alpha$'-dipyridyl, pentachlorophenol, and pCMB.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.3
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• pp.127-137
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• 2022

Zirconia is fabricated through various processes. Each element in fabricating process can affect the physical properties of the definitive prosthesis. In particular, both the milling process and the sintering process can affect the final integrity of the zirconia prosthesis. Most of the milling machines adopt the ultra-precision 5-axis machining method, and the results vary depending on which milling method was used and how the milling equipment was managed. Milling blocks are selected according to cutting efficiency and aesthetic reproducibility. The sintering method can affect the grain growth and optical properties, and an accurate evaluation can be made only with additional research on the recent speed sintering procedure. Not only the sintering temperature but also the temperature holding time can affect the quality of definitive prosthesis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2D
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• pp.243-248
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• 2008

Moisture damage of asphalt pavements can usually occur because of the loss of adhesion and cohesion between the asphalt binder and aggregate in the asphalt mixture due to presence of water. And this is one of the causes that is effect on the main distress of asphalt pavement. The objective of this study is to find out moisture damage characteristics of asphalt pavement. Effects of this study changes of the material properties and resistance characteristics of moisture damage on the asphalt mixtures under various temperatures and repeated immersion using indirect tensile test and modify Lottman test were evaluated during this study. The asphalt mixtures were produced using straight asphalt binder, SBS modified asphalt binder and aggregates. The material properties (resilient modulus, indirect tensile strength, failure energy and $DCSE_f$) of the asphalt mixtures were generally decreased with increasing to moisture damage caused by the number of repeated immersion. The decrease ratios of material properties by repeated immersion on SBS modified asphalt mixtures were lower than those of straight asphalt mixtures at all three test temperatures. As a conclusion, current criterion for evaluation moisture damage of asphalt mixtures is difficult for using distinction standard because of the limited evaluation criterion with one time immersion and single material property. Based on this research, to evaluate long term moisture damage on asphalt mixtures, material property tests of various kinds with repeated immersion test are considered.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.2
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• pp.270-283
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• 2014

본 연구는 온도 변화에 따른 해산송사리, Oryzias dancena의 마취 효과 및 생리적 스트레스 반응을 평가하고, 고온 및 저온에서 최적의 마취 수온을 구명하였다. 해산송사리에서 고온 실험($36{\sim}42^{\circ}C$)과 저온 실험($4{\sim}10^{\circ}C$)을 통해 마취 효과를 조사하였으며, 각 마취수온에서 전어체의 cortisol과 glucose를 측정하였다. 각 수온 마취 실험 후, 전개체는 모두 생존하였으며, 해산송사리의 마취시간은 고온 실험에서 고온 일수록, 저온 실험에서는 저온 일수록 유의적으로 빨랐다(P<0.05). 회복 시간은 유의하게 고온 실험에서 수온이 감소할수록, 저온 실험에서는 수온이 증가할수록 유의적으로 느렸다(P<0.05). 아가미 운동수는, 고온 실험에서 수온이 증가함에 따라 빨랐으며, 저온 실험에서는 수온이 감소할때 빨랐다(P<0.05). 수온이 $38^{\circ}C$ 나 $8^{\circ}C$ 일때의 마취 조건에서 실험직후 전어체 cortisol이 최대치로, 실험후 6시간까지 점진적으로 감소한 반면, 전어체 glucose는 실험후 1시간에 최고치를 보이고 실험후 2시간까지는 감소하였다. 기존의 마취제를 쓰지 않은 본 연구로 인해, 해산송사리의 여타 연구에서 샘플 및 사용자가 보다 더 안전하고 용이한 샘플 취급이 가능할 것으로 사료된다.

• Journal of Life Science
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• v.14 no.3
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• pp.501-508
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• 2004

A bacterial strain CJ-3 which produced chitinase was isolated from Korean traditional soy sauce. Using 16S rDNA analysis, the strain CJ-3 was identified as Bacillus atrophaeus. The approximate molecular weight of the putative chitinase enzyme was 31.0 kDa and the enzyme activity was remarkably induced by addition of colloidal chitin (0.5, 1.0, 2.0%). The antioxidant activity was increased 53% by the browning reaction products of B. atrophneus CJ-3. Escherichia. coli lipopolysaccharides (LPS)-induced production of nitric oxide(NO) was reduced up to 45% by the browning reaction product in RAW264.7 macrophage. Inhibition of cell viability in the presence of LPS was recovered to normal level by the browning reaction product. These results suggest that browning reaction of B. atrophaeus CJ-3 plays an important role for activation of immune system. B. atrophaeus CJ-3 exhibited optimum temperature and pH of 37$^{\circ}C$ and pH 7.0∼8.0, respectively. The major intracelluar free amino acid was determined to be glutamate.

• Fire Science and Engineering
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• v.16 no.1
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• pp.66-76
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• 2002

This paper includes new nozzle design, basic design factors of water mist system that minimize a thermal damage of cable causing business interruption and applying underground utility tunnel. A underground concrete structure (2.5 m(H)$\times$2.5 m(W)$\times$25 m(D)) is constructed in order to test a nozzle performance. Under the designing fire scenario, critical thermal damage of cable sheath ($400^{\circ}c$) reached within a 2 minutes with unsuppressed fire, but type 1 nozzle (SMD 470 $\mu{m}$) and type 2 nozzle (SMD 650 $\mu{m}$) control cable temperature below $400^{\circ}c$. A system performance and fundamental design factors; K factor, flow rate, spray angle, size distribution, nozzle pressure, spray density are analyzed and proposed for system optimization.