• Journal of IKEEE
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• v.22 no.3
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• pp.882-885
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• 2018

Recently, signal integrity on PCB (printed circuit board) becomes very important as the system operation speed increases. So far, PCB is customarily designed to minimize area and cost. However, ultra-high-speed PCB often fail to operate properly, unless it is precisely and carefully designed considering dielectric characteristics, line width, line spacing, and impedance matching. This paper surveys many problems in ultra-high-speed PCB and various design methods to mitigate them.

• Analytical Science and Technology
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• v.23 no.3
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• pp.312-321
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• 2010

Seven indicator PCBs (IUPAC nos 28, 52, 101, 118, 138, 153, 180 congeners) concentrations were measured in food samples including cereal (polished rice), meats, eggs, milk and dairy products, and fisheries and products as representation for the general Korean populations during 2006-2007, and was analyzed using isotopic dilution method. Fishes had the highest average level as 39.8 ng/g, 1.4 ng/g for milk and dairy products, and 0.9 ng/g for meats. The hairtail out of fishes was contaminated at the level of 15.4 ng/g, 5.4 ng/g for pacific mackerel and spanish mackerel, and 4.5 ng/g for yellow croaker. The ratio for indicator PCBs in overall food was contributed as follows; 35.8% for PCB-153, 16.2% for PCB-138, 16.1% for PCB-101, 13.4% for PCB-118, 8.8% for PCB-180, 6.9% for PCB-52, and 2.9% for PCB-28. The hexa-CBs including PCB-153 and 138 were more predominated, and the next was penta-CBs including PCB-101 and 118 in food. For estimated daily intake (EDI) in average and $95^{th}$ percentile, fishes and products out of overall food were taken to represent over 50%. However, it was estimated that there was no adverse health effect for Korean.

• Journal of the Korea Computer Industry Society
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• v.2 no.12
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• pp.1533-1540
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• 2001

In this paper, we described extraction method of electrical parameters and modeling method of PCB nets on PCB design process. To analyze electrical characteristics of real PCB structure, we selected a cache memory system as an experimental board and designed 6 layer PCB substrate. For extraction of the electrical parameters, we divided circuit elements into the components of conductor types which are wires, via holes, BGA balls etc. and combined the calculated value by real net structure to modeling the PCB nets. We analyzed the electrical characteristics of the PCB nets with the simulation tools of SPICE and XNS. The simulation analysis has shown that the maximum signal delay was 2.6ns and the maximum crosstalk noise was 281 mV and we found that the designed substrate was adequate to system specification.

• Journal of IKEEE
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• v.22 no.3
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• pp.874-877
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• 2018

Many SMDs (surface mount device) are mounted and mutually connected on a PCB (printed circuit board). System performance degrades when their transmission characteristics are bad. Pads connecting a PCB and SMDs affects PCB transmission characteristics significantly, so pad should be properly aligned to optimize impedance matching. In this paper, effects on PCB transmission characteristics are simulated by pad alignment. When frequency is relatively low, pad alignment seldom affect PCB transmission characteristics, but it affects more and more when frequency or pad size becomes larger. Therefore, pad alignment should be carefully chosen based on target frequency and pad size. Especially, the proposed edge-aligned pad is generally more advantageous over the conventional centered-aligned pad in 12~16 GHz Ku-band frequency.

• Journal of Korea Multimedia Society
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• v.12 no.3
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• pp.397-408
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• 2009

Image training is a very important yet difficult state for automated visual inspection using computers. Because the size of parts for the recently produced PCB (Printed Circuit Board) becomes smaller and circuit patterns gradually become more complex, a difficult and complex training process is becoming a big problem within an industry where development cycle for new products is short and various products must be inspected. This research produced a reference image by using CAD (Gerber) file which becomes a standard for PCB automatic visual inspection. Reference image from a Gerber file guarantees PCB patterns with no defects. Through system implementation and experimentation, Gerber file is used in order to propose a plan which allows an easy training process for PCB automatic visual inspection system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.4
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• pp.507-514
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• 2012

This paper proposed the analysis method of the cavity resonance characteristics for a metallic enclosure with a PCB trace source. In order to calculation the electromagnetic fields inside the cavity, coupled integral equations for a current distribution on the PCB trace and an aperture electric field distribution on the boundary of the PCB dielectric are derived and solved by applying Galerkin's method of moments. The result show that the resonant characteristics of the metallic enclosure are fairly good agreement with the simulation(HFSS) and the measured results. The resonant frequencies of the metallic enclosure with the PCB trace are changed by the PCB trace location inside of the cavity. In order to check the validity of the theoretical analysis, the calculated return losses are compared with the measured results.

• Korean Journal of Environment and Ecology
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• v.17 no.1
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• pp.18-25
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• 2003

In order to know the effects of PCB(Arochlor 1248) on the oocyte maturation and proges-terone(P$_4$) production by FPH(Frog pituitary homogenate: 0.01 p.e/$m\ell$) of frog in vitro, the oocytes were cultured for 20 hours in presence of the PCB at various concentrations and exam-ined their maturation(germinal vesicle breakdown: GVBD) rates and P$_4$ levels secreted by the oocyte in the culture medium. The results show that PCB concentration of 10 ppb suppressed the maturation of the oocytes and secretion of P$_4$. To examine the reversibility of the inhibitory effects, the oocytes were exposed to the PCB only for 3 hours, and then transferred to plain medium and cultured further for 17 hours. The oocytes were recovered from the toxic effect of the PCB when they were exposed to 2.5 ppb, but not to 5 ppb of the PCB. These results indi-cate that PCB suppress the maturation of oocytes and secretion of p, at low concentration, sug-gesting that the frog oocyte culture system can be used as a useful tool to evaluate the toxicity of the pollutants in the environment.

• Toxicological Research
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• v.28 no.2
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• pp.107-112
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• 2012

Polychlorinated biphenyls (PCBs) are persistent and bioaccumulative environmental pollutants. Recently, it is suggested that neurotoxic effects such as motor dysfunction and impairment in memory and learning have been associated with PCB exposure. However, structure relationship of PCB congeners with neurotoxic effects remains unknown. Since PKC signaling pathway is implicated in the modulation of motor behavior as well as learning and memory and the role of PKC are subspecies-specific, we attempted to study the effects of structurally distinct PCBs on the total PKC activity as well as subspecies of PKC in cerebellar granule cell culture model. Cells were exposed to 0, 25 and 50 ${\mu}M$ of PCB-126, PCB-169, PCB-114, PCB-157, PCB-52 and PCB-4 for 15 min. Cells were subsequently analyzed by [$^3H$] phorbol ester binding assay or immunoblotted against PKC-${\alpha}$ and -${\varepsilon}$ monoclonal antibodies. While non-dioxin-like-PCB (PCB-52 and PCB-4) induced a translocation of PKC-${\alpha}$ and -${\varepsilon}$ from cytosol to membrane fraction, dioxin-like PCBs (PCB-126, -169, -114, -157) had no effects. [$^3H$] Phorbol ester binding assay also revealed structure-dependent increase similar to translocation of PKC isozymes. While PCB-4 induced translocation of PKC-${\alpha}$ and -${\varepsilon}$ was inhibited by ROS inhibitor, the pattern of translocation was not affected in presence of AhR inhibitor. It is suggested that PCB-4-induced PKC activity may not be mediated via AhR-dependent pathway. Taken together, our findings suggest that chlorination of ortho-position in PCB may be a critical structural moiety associated with neurotoxic effects, which may be preferentially mediated via non-AhR-dependent pathway. Therefore, the present study may contribute to understanding the neurotoxic mechanism of PCBs as well as providing a basis for establishing a better neurotoxic assessment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.2567-2572
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• 2014

In the present study, we aimed to obtain multi jig that PCB sheet with several PCB component can cut in a short time as to the Separation of PCB component. PCB supporter designed safely at the base frame and each model can be separable. it completed the neodium magnet for the fixing of the upper part laser transmission hole of the both. One of the development, the cutting working with one base frame which PCB component of various standard, fixing of module and bridge connected to PCB component could be possible. and it reduced the inconvenience which has to replace the base frame and PCB sheet fixed member. It compared to other press up about 70% of accuracy and a reduction in investment cost was about 400%.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.297-297
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• 2000

This paper proposed character recognition method by using DB Matching and Artificial Neural Network at the Gerber files. Gerber files are file for make PCB. But we also use the file to a program of extraction PCB position data. If the Gerber file recognized a character, the extraction PCB position data will be faster and also when the recognition rate is high, it can be possible to automatic extraction. We apply to the construction PCB Gerber file program and Simulation results are presented to verify the usefulness of the method.