• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.11 s.114
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• pp.1132-1142
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• 2006

This paper examined electric power transmission line models of reducing ELF(Extremely Low Frequency) magnetic field and analyzed the effects about models. In this research, FRF(Field Reduction Factor) of various models reducing magnetic field were analyzed compared to the horizontal 154 kV transmission line. As a result, the reduction ratio of magnetic field was almost proportioned to the compaction of phase-to-phase distance, and in case of diamond model and transposed model, magnetic field was able to be reduced nearly 50 %. It was analyzed that the magnetic field reduction ratio of triangle model was about 33 % and the magnetic field reduction ratio of split model was able to be reduced to 50 %. Especially, the magnetic field reduction ratio of multi split model could be reduced to 80 %.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.05a
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• pp.7-8
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• 2009

Non-contact critical current measurement apparatus was developed using hall probe which measures the magnetic field distribution across the width of superconducting tape. The hall probe consists of 7 independent hall sensors which lie in a line 600 ${\mu}m$. The difference between maximum and minimum magnetic field in the magnetic filed distribution is a main parameter to determine the critical current. As preliminary research, we calculated the magnetic field intensity at the middle sensor, which is a minimum magnetic field and generated by the circular shielding current modeled by Bean model. We confirmed that there are some parameters that affect on the minimum magnetic field; the distance between superconducting layer and hall sensor, the width of superconducting tape, and the critical current distribution across the width of superconducting tape. Among these parameters, the distance between superconducting layer and hall sensor highly influences on the minimum magnetic field.

• The Journal of Pediatrics of Korean Medicine
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• v.38 no.1
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• pp.10-22
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• 2024

Objectives This bibliometric analysis aimed to determine the status of pediatric acupuncture research. Methods Relevant bibliographic information up to January 9, 2024, was collected through searches in the Web of Science Core Collection. Bibliographic information was preprocessed for data analysis and analyzed using VOSviewer software. Network maps of the authors and their affiliated institutions in the included studies were constructed and visualized, and clusters for each major node were identified. In addition, the latest research keywords were visualized using an overlay visualization function. Results The field of pediatric acupuncture research has shown a 20.5-fold quantitative increase in the number of publications over the past 30 years (1991 - 2023). In the field of pediatric acupuncture research, the United States has the highest productivity and influence, and South Korea ranked 7th in productivity and 10th in influence. Through keyword analysis in the field of pediatric acupuncture research, four clusters were identified. Pain management, use in pediatric oncology, and use in postoperative management were identified as important clinical topics. There is a lack of exchange among researchers in the field of pediatric acupuncture. Conclusions Pediatric acupuncture research continues to show quantitative growth and western countries have shown high productivity and influence in this field. In this study, the major keywords in the field of pediatric acupuncture research were identified, and the results can be used to establish the research direction of the Korean medicine community.

• Journal of Technology Innovation
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• v.10 no.1
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• pp.22-37
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• 2002

The importance of selecting the strategic research field is increasingly emphasized by research manager and technology policy-maker in perspective of the strategic allocation of R&D resources, employing the R&D personnel, and formulating technology policy. Among various methods for selecting the strategic research field, it is, however, very difficult to find the method that involves the path-dependant trend, and interdisciplinary nature of technology development. This study suggests modified technology cluster analysis (TCA) as a method for selecting strategic research field in order to include the recent technology trend in quantitative approach. TCA is the method that groups the near technologies of which the innovation pattern is similar. TCA model can be a very necessary method for multidisciplinary government research institutes (GRIs) which conduct multi research field with forward oriented positioning. It is more difficult for them to select the strategic research field mainly due to their diversity and intangibility of research scope. In this study, we applied this method to Korea Institute of Science and Technology (KIST) which represents the most adequate research institute in terms of research diversity and forwardness. As a result of the application, we found that seven main technology groups come from TCA analysis, coincide with the technology topics of KIST's recent R&D planning. Even though this method designed for multidisciplinary research institutes, but it also can be used for establishing the research strategy of other (private or public) Research Institute which have the similar mission and scope of research.

• Journal of the Korean Vacuum Society
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• v.2 no.3
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• pp.335-338
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• 1993

텅스텐으로 만들어진 field emitter와 탄소로 만들어진 field emitter에서 생기는 step이나 spike 형태의 잡음에 대하여 비교 연구하였다. 그리고 dispenser 형태의 field emiter와 array 형태의 field emitter와 같은 새로운 형태의 field emitter를 설명하였다.

• Progress in Superconductivity and Cryogenics
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• v.21 no.1
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• pp.1-5
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• 2019

The pulsed field magnetization of the short-circuited soldered double pancake coil made of stabilized commercial high-Tc superconductor (HTS) tape is experimentally studied. The evolution of the shielding current induced by the pulsed field and the trapped field after the pulsed magnetization was measured at 77 K. It is shown that the trapped field in the coil is close to the value reached in the field cooling process and reduces weakly at 5-fold increasing of pulsed field amplitude. The current relaxation at t~2 ms after the pulse is defined by the current sharing between the tape's copper coating and the $YBa_2Cu_3O_{7-d}$ layer. In the intermediate time scale (1 s < t < 100 s) the flux creep in HTS layer dominates. At t > 100 s the current's relaxation is defined by the resistance of soldered joint between tapes.

• Korean Journal of Materials Research
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• v.11 no.12
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• pp.1091-1095
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• 2001

Finite element analysis showed that strong magnetic fields were distributed around the arc furnace where the strongest magnetic field was generated around the three phase cables, and followed by the electrodes and the mast arm in decreasing order. Magnetic field decay patterns around the arc furnace could be fitted by introducing exponential formula,$Y=Y_0+Ae^{\frac-{x}{t}}$. These results showed that magnetic field intensities around the arc furnace could be estimated at any 3-dimensional positions using the finite element method (FEM).

• Journal of Electrical Engineering and Technology
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• v.5 no.3
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• pp.400-406
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• 2010

This paper deals with parameter tuning of the Power System Stabilizer (PSS) for 612 MVA thermal power plants in the KEPCO system and its validation in a field test. In this paper, the selection of parameters, such as lead-lag time constants for phase compensation and system gain, is optimized using linear and eigenvalue analyses. This is then verified through the time-domain transient stability analysis. In the next step, the performance of PSS is finally verified by the generator's on-line field test. After the field test, measured and simulated data are also compared to prove the effectiveness of the models used in the simulations.

• ETRI Journal
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• v.21 no.3
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• pp.22-28
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• 1999

A new tapered TEOS oxide technique has been developed to use field oxide of the power integrated circuits. It provides better uniformity of less than 3 % and reproducibility. On-resistance of P-channel RESURE (REduced SURface Field) LDMOS transistors has been optimized and improved by using a novel simulation and tapered TEOS field oxide on the drift region of the devices. With the similar breakdown voltage, at $V_{gs}$=-0.5V, the specific on-resistance of the LDMOS with the tapered field oxide is about $31.5{\Omega}{\cdot}cm^2$, while that of the LDMOS with the conventional field oxide is about $57m{\Omega}{\cdot}cm^2$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05a
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• pp.50-54
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• 2003

The output characteristics of thin film NiO/NiFe bilayered magnetoresistive device have been measured as a function of the direction of external magnetic field. Each layer was fabricated by rf magnetron sputtering method, and especially, the under layer, NiO, was fabricated under the in-situmagnetic field of about 1000Oe. The magnetoresistive devices were designed with the angle of 45degree between the direction of current of the device pattern and the induces magnetic field in the NiO film layer. The output of the devices had a good linearity when the devices were placed on the external magnetic field perpendicular to induced field direction and also 45 degree with the currenr path direction.