• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.19.1-19.1
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• 2010

The process of manufacturing printed electronics using printing technology is attracting attention because its process cost is lower than that of the conventional semiconductor process. This technology, which offers both a lower cost and higher productivity, can be applied in the production of organic TFT (thin film transistor), solar cell, RFID(radio frequency identification) tag, printed battery, E-paper, touch screen panel, black matrix for LCD(liquid crystal display), flexible display, and so forth. In general, in order to implement printed electronics, narrow width and gap printing, registration of multi-layer printing by several printing units, and printing accuracy of under $20\;{\mu}m$ are all required. These electronic products require high precision to the degree of tens of microns - in a large area with flexible material, and mass productivity at low cost. As such, the roll-to-roll printing process is attracting attention as a mass production system for these printed electronic devices. For the commercialization of this process, two basic electronic ink technologies, such as conductive ink and polymers, and printing equipment have to be developed. Therefore, this paper addressed basis design and test to develop fine patterning equipment employing the roll-to-roll printing equipment and electronic ink.

• Journal of the Korean Society of Safety
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• v.13 no.2
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• pp.22-29
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• 1998

The natural convection cooling of simulated electronic chips located on a printed circuit board(PCB) has been studied by Computer Aided Engineering(CAE). In CAE, 3-dimensional finite element model of simulated electronic chip was made to accomplish heat transfer analysis at each design stage of a printed circuit boards for thermal optimization. The simulated electronic chips are installed protrudent from the plate about 3mm. The materials the plates are epoxy and aluminum. The results show that the chip with relatively high heat generation rates should not be close to each other. It is found, as well that cooling effect for the aluminum plate is superior to the epoxy plate and location of maximum temperature is significantly influenced by the structure variation of PCB. In developing PCB and electronic chips, it's recommended that CAE is very useful to estimate to the distribution of temperature.

• Journal of electromagnetic engineering and science
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• v.4 no.1
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• pp.8-12
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• 2004

In this paper, a triple-band printed dipole antenna using parasitic elements is proposed for the multiple wireless services. The proposed antenna is designed and experimentally analyzed at the bands of PCS, IMT-2000, and ISM services. To achieve triple frequency operation, the proposed antenna contains two parasitic elements, which act as additional resonators by coupling from the driving dipole antenna. From the measured results, the resonant frequencies of this antenna are 1.79 ㎓, 2.03 ㎓, and 2.41 ㎓ and the measured impedance bandwidths are 90 MHz(1760∼1850 MHz), 210 MHz(1,930∼2,130 MHz), and 30 MHz(2,400∼2,430 MHz) for VSWR<2. The measured antenna gains are 2.14 ㏈i, 0.9 ㏈i, and 0.5 ㏈i, respectively. Antenna parameters for trifle-band operation are investigated and several antenna characteristics are discussed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.2
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• pp.161-161
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• 2020

• Journal of the Korean Society for Library and Information Science
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• v.52 no.1
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• pp.259-283
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• 2018

This research aims at understanding the differences between expert and general users' perceptions regarding publication preferences for Korean classics collations and translations in order to formulate future directions for these materials. For this purpose, an overview of changes in publishing in general as well as current status of collation/translation of Korean classics in particular are being identified. An online questionnaire was carried out in order to collect data regarding perceptions and preferences of expert users and general users of Korean classics. The results are based on the analyses of more than 1,000 responses. The analyses show that electronic books will not completely replace printed books and publishing both electronic and printed books in tandem for the time being is most preferable in order to satisfy varying user needs. Statistical analysis shows differences in terms of use value, value from possession, and readability of electronic and printed books in the two groups of users. However, as for the value of preservation by relevant institutions, there was a statistical difference between two groups towards printed books unlike their electronic equivalents. The research shows strong preference towards printed forms of classics collations and translations for the purpose of scholarly research and translation. Actual usage statistics reveal much heavy use of online database of classics translations compared to the use of available electronic books. For future publishing decisions for classics collations and translations will need to take into consideration of their special characteristics and symbolic nature. Proper representation of these materials into electronic format would require a standardized platform that enable various uses in different environments.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.223-224
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• 2008

Important element are low cost, high-efficiency crystalline silicon solar cells. in this paper, Will be able to contribute in low cost, high-efficiency silicon solar cells, Applies oxide/nitride passivation, produced screen-printed solar cells. and the Measures efficiency, and evaluated a justice quality oxide/nitride passivation screen-printed solar cells.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.551-552
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• 2006

This study was attended to demonstrate synthesis of silver nanoparticles stabilized with polymer and their applicability to printed electronics. Silver nanoparticles were synthesized by reduction of silver nitrate in aqueous solution in the presence of polyvinyl pyrrolidone (PVP) as a stabilizer. The ink used here is composed of 50 wt% Ag NP, 15 wt% humectant and then were printed on polyimide film. Particle deposit morphologies were controlled by varying the ink compositions. Printed silver patterns and dots were cured on a convection oven in air at $300^{\circ}C$ for 60 min. The printed patterns show good shape definition and the resistivity of the printed films is about $5{\mu}{\Omega}{\cdot}cm$.

• Transactions on Electrical and Electronic Materials
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• v.13 no.3
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• pp.129-135
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• 2012

A number of surface mount technology (SMT) process variables including land design are considered for minimizing tombstone defect in flexible printed circuit assembly in high volume manufacturing. As SMT chip components have been reduced over the past years with their weights in milligrams, the torque that once helped self-centering of chips, gears to tombstone defects. In this paper, we have investigated the correlation of the assembly process variables with respect to the tombstone defect by employing statistically designed experiment. After the statistical analysis is performed, we have setup hypotheses for the root causes of tombstone defect and derived main effects and interactions of the process parameters affecting the hypothesis. Based on the designed experiments, statistical analysis was performed to investigate significant process variable for the purpose of process control in flexible printed circuit manufacturing area. Finally, we provide beneficial suggestions for find-pitch PCB design, screen printing process, chip-mounting process, and reflow process to minimize the tombstone defects.

• Korean Journal of Computational Design and Engineering
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• v.9 no.4
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• pp.416-424
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• 2004

In this paper, the heat transfer analysis and thermal stress analysis of the PCB(Printed Circuit Board) equipped in electronic Packages are carried out for various may types of chips on the PCB. And two structural PCB models are used in the analyses. The electronic chips on the PCB usually emit heat and this heat generates the thermal stress around the chip. The thermal load due to the heat generation of chips on the PCB may cause the malfunction of the electronic packages such as a monitor. a computer etc. Hence, the PCB should be designed to withstand these thermal loads. In this paper, the heat transfer analysis and thermal stress analysis are executed for the PCB model with pins and the analysis results are compared with the results for the PCB model without pins. The analysis results show that the PCB model without pins is not good for the thermal stress analysis of PCB, even though these two models have similar heat transfer characteristics. The analysis results also show that the highest thermal stress occurs in the pin especially attached to the highest temperature chip, and the PCB constrained to the electronic package on the long side is structurally more stable than other cases. The analyses of the PCB are executed using the finite element analysis code, NISA.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.6
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• pp.1033-1038
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• 2022

In this paper, the design of a printed dipole antenna fed by broadside coupled striplines (BCS) for the 3.5GHz band is described. The two fins of the bow tie are, respectively, on the two sides of the substrate. The feeding balanced lines adopted for 1×2 array are the BCS. The obtained numerical results are in good agreement with experimental data. Through experiments with printed dipole antennas of various extended angles, the printed dipole antenna exhibits the wide bandwidth in the desired frequency band, which has a bandwidth of 28% for VSWR < 2.0 : 1. And within this bandwidth, This printed dipole antenna achieves a stable radiation pattern. It is found that the narrow band and feeding for array characteristic which is a disadvantage of the conventional printed dipole antenna can be improved. The radiation pattern showed omnidirectional characteristics and the maximum gain was about 4.4dBi.