• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.283-287
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• 2007

KIER has been developing the anode-supported flat tubular solid oxide fuel cell unit bundle for the intermediate temperature($700{\sim}800^{\circ}C$) operation. Anode-supported flat tubular cells have Ni/YSZ cermet anode support, 8 moi.% $Y_2O_3$ stabilized $ZrO_2(YSZ)$ thin electrolyte, and cathode multi-layer composed of Sr-doped $LaSrMnO_3(LSM)$, LSM-YSZ composite, and $LaSrCoFeO_3(LSCF)$. The prepared anode-supported flat tubular cell was joined with ferritic stainless steel cap by induction brazing process. Current collection for the cathode was achieved by winding Ag wire and $La_{0.6}Sr_{0.4}CoO_3(LSCo)$ paste, while current collection for the anode was achieved by using Ni wire and felt. For making stack, the prepared anode-supported flat tubular cells with effective electrode area of $90\;cm^2$ connected in series with 12 unit bundles, in which unit bundle consists of two cells connected in parallel. The performance of unit bundle in 3% humidified $H_2$ and air at $800^{\circ}C$ shows maximum power density of $0.39\;W/cm^2$ (@ 0.7V). Through these experiments, we obtained basic technology of the anode-supported flat tubular cell and established the proprietary concept of the anode-supported flat tubular cell unit bundle.

• Food Science and Preservation
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• v.20 no.3
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• pp.289-295
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• 2013

The capacity of a pressure fan can be designed based on the air flow resistance of containers packed with fruits and vegetables in a pressure cooling system. This study was conducted to develop an air flow resistance model that was dependent on changes in the air flow rate and the method of stacking containers. The air flow resistance of a container packed with uniformly shaped balls was 1.5 times greater than the sum of the air flow resistance of a vacant container and that of a wire net container packed with only balls. In addition, the air flow resistance increased exponentially as the width of the stacks increased; however, the air flow resistance did not increase greatly as the length and height of the stacks increased, which indicates that the air flow resistance is primarily influenced by the width of the stack in the air flow direction. The air flow resistance in two lines of stacking was up to 17% less than that of the width of the stack. It was also possible to determine the air flow resistance using a function of the air flow resistance through a single container and develop a prediction model. A prediction model of air flow resistance that is dependent on the stacking method and the air flow resistance of a single container was developed.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1023-1026
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• 2005

In the ubiquitous computing environment, an intelligent vehicle is defined as a sensor node with a capability of intelligence and communication in a wire and wireless network space. To make it real, a lot of problems should be addressed in the aspect of vehicle mobility, in-vehicle communication, common service platform and the connection of heterogeneous networks to provide a driver with several intelligent information services beyond the time and space. In this paper, we present an intelligent information system for managing in-vehicle sensor network and a vehicle gateway for connecting the external networks. The in-vehicle sensor network connected with several sensor nodes is used to collect sensor data and control the vehicle based on CAN protocol. Each sensor node is equipped with a reusable modular node architecture, which contains a common CAN stack, a message manager and an event handler. The vehicle gateway makes vehicle control and diagnosis from a remote host possible by connecting the in-vehicle sensor network with an external network. Specifically, it gives an access to the external mobile communication network such as CDMA. Some experiments was made to find out how long it takes to communicate between a vehicle's intelligent information system and an external server in the various environment. The results show that the average response time amounts to 776ms at fixed place, 707ms at rural area and 910ms at urban area.

• Journal of IKEEE
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• v.20 no.3
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• pp.279-284
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• 2016

This paper presents a two stage L-band power amplifier realized with a $0.32{\mu}m$ Silicon-On-Insulator (SOI) CMOS technology. To overcome a low breakdown voltage limit of MOSFET, stacked-FET structures are employed, where three transistors in the first stage amplifier and four transistors in the second stage amplifier are connected in series so that their output voltage swings are added in phase. The stacked-FET structures enable the proposed amplifier to achieve a 21.5 dB small-signal gain and 15.7 dBm output 1-dB compression power at 1.9 GHz with a 122 mA DC current from a 4 V supply. The amplifier delivers a 19.7 dBm. This paper presents a two stage L-band power amplifier realized with a $0.32{\mu}m$ Silicon-On-Insulator (SOI) CMOS technology. To overcome a low breakdown voltage limit of MOSFET, stacked-FET structures are employed, where three transistors in the first stage amplifier and four transistors in the second stage amplifier are connected in series so that their output voltage swings are added in phase. The stacked-FET structures enable the proposed amplifier to achieve a 21.5 dB small-signal gain and 15.7 dBm output 1-dB compression power at 1.9 GHz with a 122 mA DC current from a 4 V supply. The amplifier delivers a 19.7 dBm saturated output power with a 16 % maximum Power Added Efficiency (PAE). A bond wire fine tuning technology enables the amplifier a 23.67 dBm saturated output power with a 20.4 % maximum PAE. The die area is $1.9mm{\times}0.6mm$.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.4
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• pp.91-96
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• 2014

Through silicon via (TSV) technology is to form a via hole in a silicon chip, and to stack the chips vertically for three-dimensional (3D) electronics packaging technology. This can reduce current path, power consumption and response time. In this study, Cu-filling substrate size was changed from Si-chip to a 4" wafer to investigate the behavior of Cu filling in wafer level. The electrolyte for Cu filling consisted of $CuSO_4$ $5H_2O$, $H_2SO_4$ and small amount of additives. The anode was Pt, and cathode was changed from $0.5{\times}0.5cm^2$ to 4" wafer. As experimental results, in the case of $5{\times}5cm^2$ Si chip, suitable distance of electrodes was 4cm having 100% filling ratio. The distance of 0~0.5 cm from current supplying location showed 100% filling ratio, and distance of 4.5~5 cm showed 95%. It was confirmed good TSV filling was achieved by plating for 2.5 hrs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.261-267
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• 2020

The demand for faster, lighter, and thinner portable electronic devices has brought about a change in semiconductor packaging technology. In response, a stacked chip-scale package(SCSP) is used widely in the assembly industry. One of the key materials for SCSP is a die-attach film (DAF). Excellent flowability is needed for DAF for successful die attachment without voids. For DAF with high flowability, two-step curing is often required to reduce a cure crack, but one-step curing is needed to reduce the processing time. In this study, DAF composition was categorized into three groups: cure (epoxy resins), soft (rubbers), hard (phenoxy resin, silica) component. The effect of the composition on a cure crack was examined when one-step curing was applied. The die-attach void and flowability were also assessed. The cure crack decreased as the amount of hard components decreased. Die-attach voids also decreased as the amount of hard components decreased. Moreover, the decrease in cure component became important when the amount of hard component was small. The flowability was evaluated using high-temperature storage modulus and bleed-out. A decrease in the amount of hard components was critical for the low storage modulus at 100℃. An increase in cure component and a decrease in hard component were important for the high bleed-out at 120℃(BL-120).