• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1210-1215
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• 2010

The probe card are test modules which are to classify the good semiconductor chips and thin film before the packaging process. In the rapid growth a technology of semiconductor, the number of pads per unit area is increasing and pad arrays are becoming irregular. Therefore, the technology of probe card needs narrow width and lots of probe tip. In this paper, the probe tip based on the MEMS(Micro Electro Mechanical System)technology was developed a new MEMS probe tip for vertical probe card applications. For the structural designs of probe tip were performed to mechanical characteristics and structural analysis using FEM(Finite Element Method). Also, the contact force of MEMS probe tip compared with FEM results and experimental results. Finally, the MEMS probe card was developed a fine pitch smaller than $50{\mu}m$.

• The Journal of the Acoustical Society of Korea
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• v.39 no.2
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• pp.87-97
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• 2020

In this paper, the design of piezoelectric Micro-machined Ultrasonic Transducer (pMUT) for wideband ultrasonic radiation in air was investigated. One of the methods to achieve wide frequency bandwidth in single device is modeling the transducer to multi-resonance system. The new pMUT was designed as a multi-resonance system with the addition of a suitable acoustic structure to the front and back of a thin film structure. A new pMUT consisting of thin film parts, radiation parts, and packaging parts is designed with a Lumped Parameter Model (L.P.M). Finally, it was validated as a Finite Element Method (FEM) simulation. The final designed pMUT achieved a frequency band of 102 kHz ~ 132 kHz (-3 dB).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.1
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• pp.91-94
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• 2018

We develop a time-temperature indicator (TTI) that can determine whether thawing of fish and other fishery products has occurred during frozen storage. A polypropylene tube with an internal diameter of 3 mm was prepared and cut to a length of 14 to 20 mm. One end of the tube was thermally sealed and 0.1% acetic acid was injected into the other end; the tube was then frozen at $20^{\circ}C$. Then the open side of the frozen tube was blocked by sinking the tube into a 10% gelatin solution. The tube was attached to a polyvinyl packaging bag along blue litmus paper and the bag was put into a freezer at $-20^{\circ}C$. After freezing, the bag was removed to an ambient temperature of $20^{\circ}C$, and the time dependence of the color change of the litmus paper was observed. The color changed from blue to red, with the length of the red region increasing with time. Our TTI can be used as a part of a visible detection system and the detection program can conduct the elapsed time analysis on the length of the red region of the litmus paper indicating the degree of thawing. Thus, the TTI is a useful tool in the temperature management of frozen fish and fishery products.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.3
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• pp.49-55
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• 2012

Even though corrugated boards are the most common packaging materials for agricultural products, conventional corrugated boards are not able to maintain the freshness of agricultural products. In order to overcome the limitations of conventional corrugated boards, a new hybrid corrugated board-composed of linerboard, a corrugating medium, and non-woven fabric-was designed to possess antibacterial, high porous and shock-absorbing properties. In this study, we compared the physical properties of non-woven fabric to those of the base papers of conventional corrugated boards and developed a new adhesive system as a first step toward manufacturing the hybrid corrugated board. We found that the non-woven fabric, which had relatively high elongation, was applicable in the corrugated board process, and that the manufacturing conditions must be controlled in order to prevent the break of the non-woven fabric. The mixture of starch and styrene-butadiene (SB) latex showed high adhesive strength, but the addition level of SB latex should not exceed 30% in starch solution.

• Composites Research
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• v.35 no.2
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• pp.69-74
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• 2022

In this study, the conductive paste used in a wide range such as wiring in the electronic packaging field, the automobile industry, and electronic products is manufactured under various process conditions due to the simplicity of the process, and then the thermal, mechanical, and electrical characteristics are analyzed and simulation studies are conducted to optimize the process. to establish the conditions of the conductive paste manufacturing process. First, a conductive paste was prepared by setting various types of binder resin, an essential component of the conductive paste, and characteristics such as thermal conductivity, tensile strength, and elongation were analyzed. Among the binder resins, the conductive paste applied with a flexible epoxy material had the best physical properties, and a simulation study was conducted based on the physical property data base of the conductive face. As a result of the simulation, the best physical properties were exhibited when the Ag flake volume fraction was 60%.

• Journal of the Semiconductor & Display Technology
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• v.21 no.2
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• pp.57-67
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• 2022

The curing characteristics of naphthalene type epoxy resin systems according to the change of curing agent were investigated to develop a new next-generation EMC(Epoxy Molding Compound) with excellent warpage characteristics, low thermal expansion, and excellent fluidity for WLP(Wafer Level Package). As epoxy resins, DGEBA, which are representative bisphenol type epoxy resins, NE-16, which are the base resins of naphthalene type epoxy resins, and NET-OH, NET-MA, and NET-Epoxy resins newly synthesized based on NE-16 were used. As a curing agent, DDM (Diamino Diphenyl Methane) and CBN resin with naphthalene moiety were used. The curing reaction characteristics of these epoxy resin systems with curing agents were analyzed through thermal analysis experiments. In terms of curing reaction mechanism, DGEBA and NET-OH resin systems follow the nth curing reaction mechanism, and NE-16, NET-MA and NET-Epoxy resin systems follow the autocatalytic curing reaction mechanism in the case of epoxy resin systems using DDM as curing agent. On the other hand, it was found that all of them showed the nth curing reaction mechanism in the case of epoxy resin systems using CBN as the curing agent. Comparing the curing reaction rate, the epoxy resin systems using CBN as the curing agent showed a faster curing reaction rate than them with DDM as a hardener in the case of DGEBA and NET-OH epoxy resin systems following the same nth curing reaction mechanism, and the epoxy resin systems with a different curing mechanism using CBN as a curing agent showed a faster curing reaction rate than DDM hardener systems except for the NE-16 epoxy resin system. These reasons were comparatively explained using the reaction rate parameters obtained through thermal analysis experiments. Based on these results, low thermal expansion, warpage reduction, and curing reaction rate in the epoxy resin systems can be improved by using CBN curing agent with a naphthalene moiety.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_3
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• pp.1239-1246
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• 2022

This paper introduces the effect of grease on the degradation characteristics of bearings used as key components of packaging equipment and automation systems. Bearings parts are installed to fix and support the rotating body of the system, and performance degradation of the bearings has a great effect on the life of the system too. When bearings are used in various devices and systems, the grease is applied to reduce friction and improve fatigue life. Determining the type of lubricant (grease) is important because it has a great influence on the operating environment and lifespan and ensures long lifespan of systems and facilities. However, studies that simultaneously compared and analyzed the change in mechanical degradation characteristics and the comparison of chemical degradation characteristics according to grease types under actual operating conditions are insufficient. In this paper, three types of small harmonic drive, high-load reducer, and low-load reducer grease used in power transmission joint modules are experimentally selected and finally injected into ball bearings with a load (19,500N) to improve bearing durability. Degradation characteristics were tested by attaching to test equipment. At this time, after the durability test under the same load conditions, the mechanical degradation characteristics, that is temperature, vibration according to the three greases types. In addition, the chemical degradation characteristics of the corresponding grease was compared to present the results of mutual correlation analysis.

• Journal of the Korean Society of Food Culture
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• v.25 no.6
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• pp.725-733
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• 2010

This study examined the understanding and use of information on nutrition labels based on one serving size among female consumers above the age of 20 in Seoul area. According to the survey, 69.9% of respondents were aware of the current system of nutrition labeling based on one serving size, and 51.8% of the respondents expressed their dissatisfaction with the system because the nutrition labels were difficult to understand or appeared unreliable. The nutrition label literacy of the consumers varied with respect to different packaging units. The respondents were likely to be less accurate in calculating the expected caloric intake when only portions of a multi-serving package were used. Initially 69.0% of respondents reported that they had read the nutrition label before purchasing a product but 91.9% of respondents said that they would check the label after learning how to read the label properly. It is very important to make consumers aware that the labels are very reliable sources of nutrition information. A public education campaign on the use of nutrition labels should focus on developing the consumers' ability and skills in using the label information when choosing foods.

• Journal of Environmental Health Sciences
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• v.50 no.3
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• pp.212-220
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• 2024

Background: 2-Ethylhexyl diphenyl phosphate (EHDPP) is widely used as a flame-retardant plasticizer in the production of polyvinyl chloride, adhesives, and food packaging. This chemical has been frequently detected in water, sediment, and indoor environments, and its lipophilicity raises concerns about bioaccumulation. Objectives: In this study, the effects of EHDPP on the development, behavioral changes, and growth hormone (GH) endocrine system of zebrafish larvae were investigated. Methods: Fertilized embryos were exposed to various concentrations (control, solvent control, 0.07, 0.7, 7, 70, and 700 ㎍/L) of EHDPP for 96 h. Developmental toxicity endpoints were observed daily. Behavioral changes under light-dark-light conditions and changes in hormones and genes related to GH/insulin-like growth factors (IGFs) axis were determined. Results: Significant decreases in survival, body length and moving distance were observed in zebrafish larvae exposed to 70 and 700 ㎍/L EHDPP. The concentrations of GH and IGF-1 were significantly decreased in zebrafish larvae exposed to 70 and 700 ㎍/L EHDPP. This change was well supported by changes in the transcription of genes involved in GH, IGF, IGF receptors, and IGF binding proteins. Conclusions: Our observations showed that exposure to 70 and 700 ㎍/L EHDPP could disrupt the feedback circuits of the GH/IGFs axis, ultimately leading to developmental toxicity, hypoactivity, and mortality.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.4
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• pp.113-117
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• 2016

Recently, hydrogen is regarded as important energy in the future, because it is clean and renewable. The photoelectrochemical (PEC) system, which produce hydrogen using water splitting by solar energy, is one of the most promising energy systems because it has abundant energy sources and good theoretical efficiency. GaN has recently been regarded as suitable photoelectrode that could be used to split water to generate hydrogen without extra bias because its band edge position include water redox potential ($V_{redox}=1.23$ vs. SHE). GaN also shows considerable corrosion resistance in aqueous solutions and it is possible to control its properties, such as structure, band gap, and catalyst characteristics, in order to improve solar energy conversion efficiency. But, even if the band edge position of GaN make PEC reaction facilitate without bias, the overpotential of oxygen evolution reaction could reduce the efficiency of system. One of the ways to decrease overpotential is introduction of co-catalyst on photoelectrode. In this paper, we will investigate the effect of manganese dioxide ($MnO_2$) as a co-catalyst. $MnO_2$ particles were dispersed on GaN photoelectrode by spincoater and analyzed properties of the PEC system using potentiostat (PARSTAT4000). After coating $MnO_2$, the flat-band potential ($V_{fb}$) and the onset voltage ($V_{onset}$) were moved negatively by 0.195 V and 0.116 V, respectively. The photocurrent density increased on $MnO_2$ coated sample and time dependence was also improved. These results showed $MnO_2$ has an effect as a co-catalyst and it would enhance the efficiency of overall PEC system.