• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.165-170
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• 2001

The main purpose of this study is to generate a fine copper oxide powder of high purity, with a compact structure and a uniform particle size by a spray pyrolysis process. The raw material is a waste copper chloride solution formed in the manufacturing process of Print Circuit Board (PCB). This study also examines the influences of various factors on the properties of the generated powder. These factors include the reaction temperature, the inflow speed of the raw material solution, the inflow speed of the air, the size of the nozzle tip, and the concentration of the raw material solution. It is discovered that, as the reaction temperature increases from 80$0^{\circ}C$ to 100$0^{\circ}C$ , the particle size of the generated powder increases accordingly, and that the structure of the powder becomes much more compact. When the reaction temperature is 100$0^{\circ}C$, the particle size of the generated powder increases as the concentration of copper in the raw material solution increases to 40g/l, decreases as the concentration increases up to 120g/l, and increases again as the concentration reaches 200g/1. In the case of a lower concentration of the raw material solution, the generated powder appears largely in the form of CuO. As the concentration increases, however, the powder appears largely in the form of CuCl. When the concentration of copper in the raw material solution is 120g/1, the particle size of the generated powder increases as the inflow speed of the raw material solution increases. When the concentration of copper in the raw material solution is 120g/1, there is no evident change in the particle size of the generated powder as the size of the nozzle tip and the air pressure increases. When the concentration is 40g/1, however, the particle size keeps increasing until the air pressure increases to 0.5kg/$\textrm{cm}^2$, but decreases remarkably as the air pressure exceeds 0.5kg/$\textrm{cm}^2$.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.12
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• pp.109-114
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• 2004

In this paper, we introduce the concept of ILCTL(inductively loaded compact transmission line) that is new type of compact transmission line. ILCTL was realized by periodic narrow transverse slits working as series inductances in microstrip line. And compact hybrid rat-race couplers were designed by using the proposed ILCTL. The microstrip line hybrid rat-race coupler with silts of 8 per quarter wavelength at 1.8 GHz has reduced size of 60% as compared with conventional one and it is proved by simulation of EM solver with full-wave analysis based on MoM and measurements.

• Journal of Creative Information Culture
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• v.5 no.3
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• pp.345-353
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• 2019

Several studies have been proposed to improve storage space efficiency by expressing binary trie data structure as a linear binary bit string. Compact binary tree approach generated using one binary trie increases the key search time significantly as the binary bit string becomes very long as the size of the input key set increases. In order to reduce the key search range, a hierarchical compact binary tree technique that hierarchically expresses several small binary compact trees has been proposed. The search time increases proportionally with the number and length of binary bit streams. In this paper, we generate several binary compact trees represented by full binary tries hierarchically. The search performance is improved by allowing a path for the binary bit string corresponding to the search range to be determined through simple numeric conversion. Through the performance evaluation using the worst time and space complexity calculation, the proposed method showed the highest performance for retrieval and key insertion or deletion. In terms of space usage, the proposed method requires about 67% ~ 68% of space compared to the existing methods, showing the best space efficiency.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.2
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• pp.223-230
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• 2012

This paper deals with an design of axial flux electric machine which is a key element for a compact size in a portable and manual generator system. It is expected that the generator system with an axial flux electric machine is more light and has higher efficiency than other types of generator systems. And it is used the soft magnetic composite core instead of silicon steel core in the axial flux electric machine for more compact size. The weight and efficiency of the generator system are the main keys to select the value of design variables. In this paper, the overall design process to meet the design goals, and the design results are presented with experiment results.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.5
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• pp.673-680
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• 2017

In the proposed paper, we designed low noise frequency synthesizer with compact size for Multi-Band. The proposed frequency synthesizer consists of fundamental frequency band(2 GHz) and harmonic frequency band(4 GHz). To improve the phase noise and spurious level of frequency synthesizer, we analyze how the configuration of frequency synthesizer affect the phase noise and design the multi-band's structure. The implemented frequency synthesizer reduce both the phase noise and spurious level. The phase noise is -92.17 dBc/Hz at 1 kHz frequency offset in 2 GHz and -90.50 dBc/Hz at 1 kHz frequency offset in 4 GHz. All spurious signals including fundamental frequency are suppressed at least 20 dBc than the second harmonic frequency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.46-47
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• 2009

In this paper, a power combiner using IPD process for SK Telecom 3-Generation (2.13 ~ 2.15 GHz) application. The Integrated Passive Device (IPD) Wilkinson power Combiner shows compact size and high performance. It is simulated by 3D Electro Magnetic (EM) simulation because of more accurate measurement result wire-bonding effects. This combiner exhibit size of $1.2mm^2$ the insertion loss of 3.6 dB, and the return loss of 10.1 dB, and isolation of more than -7.7 dB.

• Particle and aerosol research
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• v.9 no.4
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• pp.253-260
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• 2013

For a vertical atmospheric aerosol distribution measurement, a very compact and light particle sampling package is developed. This package includes a compact optical particle counter (Hy-OPC), a light and small condensation particle counter (Hy-CPC), sensors (GPS, wind velocity, temperature, humidity), and a communication and system control board. This package is attached to He balloon and the altitude is controlled by a winch. Using this system the vertical particle size distribution was measured. The test results showed that the ground base atmospheric particle measurement result may be a lot different from that high above the ground.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.1
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• pp.84-89
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• 1997

Recentely, a compact and small size air-cleaning Electrostatic Precipitator(ESP) is needed to develop for air conditioning devices. From Deutsch formula for ESP efficiency, collection efficiency is affected not only the structure of collection section but also the charge rate of dust. In terms of collection area, the most useful type is a scroll type ESP. In this work, we investigated experimentally aptimum design factor of scroll type ESP by application of Taguchi method. And we developed the scroll type ESP by using optimal condition of control factor.

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.788-792
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• 2014

It has been a critical issue to reduce the size of spectrometers in many fields such as on-chip chemical and biological sensing. The proposed plasmonic channel-waveguide with a sub-micrometer width has a cutoff frequency which enables us to control wavelength dependent propagation properties. We focused on the capability of the waveguide for spectral-to-spatial mapping when the waveguide width changes gradually. In this paper, we propose a plasmonic tapered channel-waveguide structure as a compact spectrometer with a physical size of $0.24{\times}2.0{\times}0.20{\mu}m^3$. The scattering point just above the tapered waveguide moves linearly depending on the wavelength of the injecting light. The spectral-to-spatial mapping can be improved by increasing the tapered length.

• Journal of electromagnetic engineering and science
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• v.7 no.3
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• pp.134-137
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• 2007

This paper presents the design of the compact UHF Bandpass filter of CT-type with a novel mixed coupling topology. In further detail, this new coupling structure mathematically equals the transmission zero that enables particularly the better rejection performance in the stopband without increasing the filter's order. To envision this design concept, we fabricated a microstrip filter whose measurement proves to agree with the predicted performance and the suggested coupling structure reduces the overall size, and will be possibly used in the miniaturized UHF apparatus such as the RFID system.