• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.6
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• pp.97-104
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• 2010

In this paper, ICT (in circuit tester) inspection system and inspection algorithm is proposed and detects whether inferiority exists or not in the mounted device on the flexible PCB in cell phones or mobile display devices. The system is composed of PD (pin-driver) and GGM (ground guarding method). The structural characteristics of these flexible PCB are analyzed, which is needed to input or output the test signal. Test signal to investigate the characteristics of passive components is generated using modified circuit diagram and proposed inspection algorithm. PM (pin-map) is decided on the basis of circuit diagram and has the information about the kind of test signal to be applied and the pad number for the test signal to be connected. PD is designed to load a proper test signal for a specific pad and is adjusted according to PM so that the reconstructed circuit has minimum node and mash. The proposed ICT inspection system is realized using PD and GGM. Using the system, an experiment for each passive component is done to investigate the measurement accuracy of the developed system and an experiment for real flexible PCB model is done to verity the effectiveness of the system.

• Environmental Analysis Health and Toxicology
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• v.24 no.3
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• pp.251-259
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• 2009

This study was conducted to measure the concentration of PCBs in pine needles and soil in urban (Seoul, many artificial sources of PCBs), semi-rural (Anseong, small town located below Seoul in wind direction) and rural areas (Jincheon, rarely artificial sources of PCBs) in which the artificial production amount of PCBs are different. The total PCBs concentrations in pine needles, which did not show big difference in three sampling sites, were 107.5 pg/g (urban), 94.8 pg/g (semi-rural) and 78.8 pg/g (rural) respectively. The low chlorinated PCBs were major component in pine needles and the PCBs congener concentration profile of each sampling area were similar each other, and the octanol-air partitioning coefficient, Koa, highly correlated with the PCBs concentrations in pine needles. The total PCBs concentrations in soil which did show big difference in three sampling sites, were 830.0 pg/g (urban), 314.1 pg/g (semi-rural) and 136.5 pg/g (rural) respectively. The high chlorinated PCBs were major component in soil and the PCBs congener concentration profile of each sampling area were similar each other. There was no similarity between the PCBs concentration of pine needles and those of soil at each site, because of the different mechanism of deposition and volatilization processes of PCBs. The total PCBs concentrations of 2009 became 12.9 times lower than those of 2001. The reduce rate of PCB 28 was the greatest.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.390-395
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• 2001

Cooling characteristics using convection and conduction heat transfer in a parallel channel with extruding heat sources are studied numerically. A two-dimensional model has been developed for numerical prediction of transient, compressible, viscous, laminar flow, and conjugate heat transfer between parallel plates with uniform block heat sources. The finite volume method is used to solve this problem. The considered assembly consists of two channels formed by two covers and one PCB which has three uniform heat source blocks. Five different cooling methods are considered to find efficient cooling method in a given geometry and heat source. The velocity and temperature fields, local temperature distribution along surface of blocks, and the maximum temperature in each block are obtained.

• Electrical & Electronic Materials
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• v.6 no.6
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• pp.505-513
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• 1993

본 논문은 전자 부품의 Soldring기에 사용되는 접합제를 Flux를 포함한 Solder paste 대신에 도금막을 이용하기 위한 Sn 도금막 형성 프로세스를 검토한 것이다. 반도체 Device를 Packaging한 외부단자(lead frame)과 HIC상의 후막전극(Ag/Pd)과의 접합 및 PCB상의 Cu land와의 접합시에는 스크린 프린트에 의한 Solder Paste가 일반적으로 사용되고 있다. 본 논문은 Fluxless Soldering의 한수단으로 도금막을 lead상에 형성시켜 접합 재료로서의 형성 프로세스 및 도금막의 특성과 도금형성 Paramete와의 관련성을 실험적으로 검토한 것으로 전류밀도 200 A/m$^{2}$의 조건으로 형성한 Sn 도금막이 접합용으로 최적조건임을 밝혔다.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2594-2596
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• 1999

Recently, white good market has interest with inverter product, which has merit to on/off type with respect to energy saving and noise. But, inverter product's cost is rising, because of adding inverter circuit component. To reduce cost, inverter gate drive trend is using HVIC which needs only single voltage. Also using HVIC, designer can compact PCB'size. This paper shows application technique and key point of designing HVIC

• Journal of the Semiconductor & Display Technology
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• v.8 no.4
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• pp.25-29
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• 2009

In this study, a thin plate-type heat pipe, instead of a solid aluminium heat sink, is used to eliminate heat released from LED components for lighting. Effects of the heat pipe size and installation angle are studied both in numerically and experimentally. According to the results, temperature on LED chip, when a heat pipe is used, is $1.2^{\circ}C$ lower than using the conventional metal PCB. The overall temperature drop is $32^{\circ}C$ if the heat pipe is properly used. The highest cooling performance is obtained in the case when the angle of a heat pipe installation is $90^{\circ}$.

• Journal of Power Electronics
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• v.9 no.2
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• pp.180-187
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• 2009

When converters operate in megahertz range, the passive components and magnetic devices generate high losses. However, the eddy current issues and choices of magnetic cores significantly affect on the design stage. Apart from that, the components' reduction, miniaturization technique and frequency scaling are required as well as improvement in thermal capability, integration technique, circuit topologies and PCB layout optimization. In transformer design, the winding and core losses give great attention to the design stage. From simulation work, it is found that E-25066 material manufactured by AVX could be the most suitable core for high frequency transformer design. By employing planar geometry topology, the material can generate significant power loss savings of more than 67% compared to other materials studied in this work. Furthermore, young researchers can use this information to develop new approaches based on concepts, issues and methodology in the design of magnetic components for high frequency applications.

• Journal of the Korea Society of Computer and Information
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• v.21 no.2
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• pp.97-103
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• 2016

This paper deals with the cycle time minimization problem that determines the productivity in printed circuit board (PCB) with n components using the m placement machines. This is known as production cycle time determination problem (PCTDP). The polynomial time algorithm to be obtain the optimal solution has been unknown yet, therefore this hard problem classified by NP-complete. This paper gets the initial assignment result with the machine has minimum unit placement time per each component firstly. Then, the balancing process with reallocation from overhead machine to underhead machine. Finally, we perform the swap optimization and get the optimal solution of cycle time $T^*$ within O(mn) computational complexity. For experimental data, the proposed algorithm can be obtain the same result as integer programming+branch-and-bound (IP+B&B) and B&B.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.3210-3212
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• 2000

We designed and manufactured 300MHz NMR RF Transceiver. NMR system is composed of NMR Spectrometer, Superconductive Magnet and Pulse Programmer, GUI. NMR RF Transceiver is composed of transmitter, receiver, frequency synthesizer. T/R switch, main power amp., RF coil. To phase modulation, transmitter is composed of mixer, splitter and combiner et al. To weak signal detection, receiver is composed of pre-amp., filter, mixer et al. Each module is manufactured PCB. And installed NMR system to detect chemical component of specimen. In result, we can get the information of specimen.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.167-171
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• 2001

In PCB assembling line, it needs SMD mounter. In this paper, the feeder of the SMD mounter, which carry component to the mounter is designed. Up to now, mechanical air feeder is mainly used. But in these days, it is developed to the electrical feeder with network. There are many kind of feeders with various control technique. In this paper, the feeder with BLDC motor and LON chip is designed and implemented. Then the experimental results are presented.