• Journal of Conservation Science
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• v.30 no.4
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• pp.353-364
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• 2014

Formaldehyde(HCHO) may have a damage effect on Korean traditional textiles, because concentration is high and occurrence frequency is frequent at the exhibition room and storage area. Total 20 specimens were prepared using 4 different materials (silk, cotton, ramie, hemp) after dyeing with 5 colors (undyed, red, yellow, blue, black). The specimens were exposed to HCHO gas in the test chamber. The gas acceleration test was conducted to identify the deterioration of Korean traditional textiles according to HCHO concentration(0.5, 1, 10, 100, 500ppm), to temperature-humidity condition at HCHO 500ppm, and deterioration conditions at HCHO 500ppm. Optical, chemical, and physical evaluation was carried out after the exposure. The results, color difference, grey scale rating, formate($HCO_2{^-}$) of some textiles increased at 500ppm, while pH decreased at 500ppm. Also, color difference, grey scale rating, formate($HCO_2{^-}$) of some textiles increased double damage at high temperatures & humidity, high humidity condition. But, damages of accelerated degradation textiles were slight, because of degradation degree and degradation products. The results suggest that determined the damage to the korean traditional textile, damage level, damage-weighted condition, damage to accelerated degradation textiles. In addition, formaldehyde damaged to yellowing of red textiles, bleaching of accelerated degradation textiles, formic acid damaged to bleaching of total 20 specimens.

• Journal of the Korean Wood Science and Technology
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• v.35 no.6
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• pp.50-56
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• 2007

FAO standard for heat sterilization of wood, International standards for phytosanitary measures (ISPM) No.15, must meet heat-treated wood core temperature to be higher than $56^{\circ}C$ and keep the temperature for more than 30 minutes. This study was carried out to analyze the heat treatment characteristics of domestic pinewood sterilized with the FAO standard. To enhance the effectiveness of heat treatment process in mountainous district energy consumption and time required to reach target temperature were evaluated at various temperature and relative humidity conditions and moisture contents of wood. Heat-treatment of high temperature and high humidity reduced the required heating time. Lower humidity levels at same temperature reduced energy consumption per unit time. However, lower humidity levels could not reduce total energy consumption greatly because longer treatment time was required at that condition. It is necessary to estimate energy consumption and predict treatment time in dynamic heating and cooling situations, because it frequently happens not to meet optimum treatment condition due to poor surrounding climates and operation performance of heat treatment facility in real field.

• Korean Journal of Materials Research
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• v.10 no.3
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• pp.184-190
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• 2000

We investigated the effect of filler content on the thermo-mechanical properties of modified ACA composite materials by incorporation of non-conducting fillers and the reliability of flip chip assembly on organic substrates using modified ACA composite materials. For the characterization of modified ACA s composites with different content of non-conducting fillers, differential scanning calorimeter (DSC), and thermo-gravimetric analyzer (TGA), dynamic mechanical analyzer (DMA), and thermo-mechnical analyzer (TMA) were utilized. As the non-conducting filler content increased, CTE values decreased and storage modulus at room temperature increased. In addition, the increase in the content of filler brought about the increase of Tg^{DSC}$ and $Tg^{TMA}$. However, the TGA behaviors stayed almost the same. Contact resistance changes were measured during reliability tests such as thermal cycling, high humidity and temperature, and high temperature at dry condition. It was observed that reliability results were significantly affected by CTEs of ACA materials especially at the thermal cycling test. Results showed that flip chip assembly using modified ACA composites with lower CTEs and higher modulus by loading non-conducting fillers exhibited better contact resistance behavior than conventional ACAs without non-conducting fillers.

• Polymer(Korea)
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• v.34 no.3
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• pp.191-197
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• 2010

To improve the curing method of anisotropic conductive film (ACF) at low temperature, it was studied to replace the thermal latent curing agent of imidazole compounds by the curing agent of cationically initiating type. Thermo-mechanical properties such as glass transition temperature, storage modulus, and coefficient of thermal expansion were investigated for the analysis of curing behavior. The reliability of ACF were observed in thermal cycle and high temperature-high humidity test. ACF using cationic initiator showed faster curing, lower CTE, and higher $T_g$ than the case of using imidazole curing agent, which is important for the high temperature stability. Furthermore, ACF using cationic initiator maintained a stable contact resistance in reliability test, although it was cured at low temperature and fast rate. With these results, it was confirmed that the curing method of epoxy had great effect on thermo-mechanical properties and reliability of ACF.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.195-202
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• 2010

Cooling air-conditioning of APC (Agricultural Products processing Center) workplace is important to improve the working environment in the summer season. As existing cooling systems for air-conditioning of whole workplace are inefficient because of their high equipment operating costs, relatively inexpensive cooling system is required. The objectives of this study were to simulate the thermal flow fields in APC workplace having the positive and negative pressure type fan and pad systems and spot cooling system by using CFD software (FLUENT, 6.2) and estimate the cooling effectiveness of respective cooling systems. The results showed that the negative pressure type fan and pad system was inappropriate for the present APC workplace because of excessive outside air influx from open gateway and the positive pressure type fan and pad system created relatively low temperature field but non-uniform velocity field at worker positions. The spot cooling system could supply cool air to worker positions with relatively constant air velocity and temperature.

• Journal of the Microelectronics and Packaging Society
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• v.18 no.3
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• pp.33-37
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• 2011

In this study, the degradation mechanism of mounted chip resistors with Ag-epoxy isotropic conductive adhesives (ICAs) under the humidity exposure ($85^{\circ}C$/85%RH) was examined by electrical resistance change and microstructural study. The effect of the chloride content in Ag-epoxy ICA on joint stability was also examined. The increasing range of the electrical resistance in the typical ICA joint was greater than that in the low Cl content ICA joint. In the case of the typical ICA joint, Sn oxides such as SnO, $SnO_2$, and Sn-Cl-O were formed inhomogeneously on the surface of the Sn plating during the $85^{\circ}C$/85%RH test. In contrast, no Sn-Cl-O was found in the low Cl content ICA joint during the $85^{\circ}C$/85%RH. It is suggested that Cl in Ag-epoxy ICA accelerate the electrical degradation of Sn plated chip components joined with Ag-epoxy ICA.

• 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.

• Applied Chemistry for Engineering
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• v.10 no.3
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• pp.461-466
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• 1999

The humidity sensor containing ammonium salt was prepared from the copolymer of 2-methacryloxyethyl dimethyl 2-hydroxyethyl ammonium bromide (MDHAB)/MMA/DAEMA = 6/3/1. The humid membrane was fabricated on the gold/alumina electrode by dipping. The impedances were $298k{\Omega},\;11k{\Omega}$, and $2.3k{\Omega}$ at 40%RH, 70%RH and 90%RH, respectively, at $5^{\circ}C$ and the humidity-sensitive characteristics were suitable for low temperature humidity sensor. The temperature-dependent coefficient between $5^{\circ}C$ and $20^{\circ}C$ was found to be $-0.80%RH/^{\circ}C$ and the hysteresis falled in the ${\pm}2%RH$ range. The response time was found to be 38 sec for the relative humidity ranging from 34%RH to 88%RH at $20^{\circ}C$. The reliabilities such as temperature cycle, humidity cycle, high temperature and humidity resistance, electrical load stability, stability of long-term storage and water durability were measured and evaluated for the application as a humidity sensor.

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.554-560
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• 1998

Vinylbenzyl triphenyl phosphonium chloride(VTPC)/styrenes=3.7 copolymer was prepared for the moisture-absorptive polyelectrolyte dew sensor containing phosphonium salts. The humid membrane was fabricated on the gold/alumina electrode by dipping. The impedances were $11M{\Omega}$, $980k{\Omega}$, $50k{\Omega}$, and $11k{\Omega}$ at 70%RH, 80%RH, 90%RH and 95%RH, respectively, at $25^{\circ}C$ and the humidity-sensitive charactristic was suitable for the dew sensor. The temperature-dependent coefficient between $15^{\circ}C$ and $35^{\circ}C$ was found to be $-0.25%RH/^{\circ}C$ and the hysteresis falled in the ${\pm}2%RH$ range. The response time was found to be 45 sec for the relative humidity ranging from 70%RH to 98%RH at $25^{\circ}C$. The reliabilities such as temperature cycle, humidity cycle, high temperature and humidity resistance, electrical load stability, stability of long-term storage and water durability were measured and evaluated for the application as a dew sensor.

• Journal of Welding and Joining
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• v.35 no.3
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• pp.7-14
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• 2017

The effect of high temperature-moisture on corrosion and mechanical properties for Sn-0.7Cu, Sn-3.0Ag-0.5Cu (SAC305) solders on flexible substrate was studied using Highly Accelerated Temperature/Humidity Stress Test (HAST) followed by three-point bending test. Both Sn-0.7Cu and SAC305 solders produced the internal $SnO_2$ oxides. Corrosion occurred between the solder and water film near flexible circuit board/copper component. For the SAC305 solder with Ag content, furthermore, octahedral corrosion products were formed near Ag3Sn. For the SAC305 and Sn-0.7Cu solders, the amount of internal oxide increased with the HAST time and the amount of internal oxides was mostly constant regardless of Ag content. The size of the internal oxide was larger for the Sn-0.7Cu solder. Despite of different size of the internal oxide, the fracture time during three-point bending test was not significantly changed. It was because the bending crack was always initiated from the three-point corner of the chip. However, the crack propagation depended on the oxides between the flexible circuit board and the Cu chip. The fracture time of the three-point bending test was dependent more on the crack initiation than on the crack propagation.