• Journal of Korean Society of Environmental Engineers
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• v.22 no.5
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• pp.939-947
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• 2000

Enhanced biological phosphorus removal (EBPR) was performed in an anaerobic/aerobic sequencing batch reactor (SBR). Influent was a synthetic wastewater based on acetate as a carbon source. The sludge age and hydraulic retention time were kept at 10 days and 16 hrs, respectively, Phosphate release during the anaerobic period and phosphate uptake in aerobic period were increased gradually with time. and after about 200 days, steady-state operation could be achieved with complete removal of influent phosphate. Number distribution of microbial community in the sludge performing EBPR was investigated during the steady state operation. 17 rRNA targeted oligonucleotide probes were designed and slot hybridization technique was used to determine the number distribution of each microorganism. In the acetate fed SBR, rRNA belonging to the beta subclass of proteobacteria was the most dominant in total rRNA and rRNA matching to CTE probe was the second, rRNAs of Acinetobacter, Aeromonas and Pseudomonas, which are usually thought as phosphorus accumulating organisms in EBPR processes, constituted less than 10% of total rRNA. From this community analysis, it was inferred that microorganisms belong to the beta subclass of proteobacteia (BET) and CTE such as Rhodocyclus group were important in biological phosphorus removal. Therefore, the role of Acinetobacter, Aeromonas and Pseudomonas in the EBPR might have been overestimated.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.5
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• pp.53-59
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• 2010

There are various types of antenna fed method; coaxial probe, coupling, parasitic elements, and impedance matching. In this paper, the fed method of the proposed antenna is microstrip line type. The high frequency structure simulator (HFSS) is used to analyze the characteristics of the T-shaped microstrip antenna with various patch dimensions. In comparison with the basic microstrip antenna, this proposed T-shaped microstrip antenna with 40.38 % of patch dimensions has the optimum characteristics of resonant frequency, return loss, and radiation pattern at 2.0 GHz band.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.48.2-48.2
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• 2013

To understand the connection between active galactic nuclei (AGNs) and star formation, we investigated the relation between AGN bolometric and far-infrared (FIR) luminosities, using type-2 AGNs. By matching type-2 AGNs at z < 0.3 selected from the SDSS based on the emission-line diagnostics, against the AKARI/FIS All-Sky Survey Catalogue and the COSMOS PEP (PACS Evolutionary Probe) Survey Catalogue, we obtained a sample of 729 type-2 AGNs detected in the AKARI survey ($90{\mu}m$) and 17 ones detected in the PEP survey ($100{\mu}m$). For AGN bolometric luminosities, we adopted an estimate based on the [OIII] and [OI] line luminosities. We confirmed that there is a correlation between the AGN bolometric and FIR luminosities with a large scatter, which is consistent with previous studies. However, we claim that this correlation suffers from various artificial effects, e.g., FIR detection limits, survey volumes, and so on. We will discuss the limitations of studying the connection between AGN and star formation using currently available facilities.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.306-306
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• 2013

본 연구에서는 저가격, 대면적화를 위한 롤투롤 스퍼터를 이용하여, Index matching (히가시 야마 $125{\mu}m$)의 PET 기판 위에 ITO 박막을 성막 시킨 정전용량 방식의 터치 패널용 투명 전극에 대하여 전기적, 광학적, 구조적, 표면적 특성을 분석하였다. ITO 타겟은 미쓰이사(일본의) 주석 함량 5 wt%을 사용하였으며, 롤투롤 스퍼터는 degassing챔버와 스퍼터 챔버가 한 시스템에 구성되었고, Degassing 챔버는 좌우측의 Rewinder/Unwinder 롤러에 의해 감고 풀어지는 PET 기판의 수분 및 가스를 중앙부에 위치한 히터를 통해 제거하며, 수분 제거 후 스퍼터 챔버로 옮겨진 1,250 mm폭의 PET기판을 Unwinder/Rewinder 롤러에 장착하며, Unwinder 롤러로부터 풀려진 PET 기판은 guide 롤러를 거쳐 cooling drum과의 물리적 접촉에 의해 PET 기판의 냉각이 일어나게 된다. ITO 캐소드 전에 장착된 할로겐 히터 상부로 기판이 지나가면서 열처리가 진행되고 열처리 후 두 개의 ITO 캐소드 상부를 지나면서 연속적으로 ITO 박막이 PET 기판에 성막 되게 된다. ITO 박막의 주요 성막 변수인 DC Power, Ar/$O_2$ 가스 유량비, 기판의 속도는 최적으로 고정하고, 성막된 ITO박막의 필름을 각각 고온 챔버에서 $150^{\circ}C$도에서 10 min에서 60 min 동안 각각 열처리를 통한 내열성 테스트를 진행하여 ITO 필름의 특성 향상을 비교 분석하였다. 분석을 위해 전기적 특성은 four-point probe로 측정했고, 투과도는 Nippon Denshoku사(社)의 COH-300A를 이용해 가시광(550 nm)에서 분석했고, FE-SEM으로 ITO박막의 표면 상태를 분석하였다. 또한 Rolling Tester (Z-300)를 이용하여 기계적 안정성을 분석하였다.

• Journal of the Korean Ceramic Society
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• v.18 no.2
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• pp.99-104
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• 1981

Glass-ceramics possessed a number of characteristics which suggested their suggested their use for sealing to metals. The choice of particular glass-ceramics compositions for this application is governed by various factors, including workability of the glasses, thermal expansion characteristics and the matching of these to appropriate metals. Other properties, such as mechanical strength, determined the performance of glass-ceramics to metal seals. The purpose of the present study was to investigate direct sealing behaviour of copper to $Li_2O-ZnO-SiO_2$ system glass-ceramics. The design of the seal was a concentric seal which might contribute to the strong bond formation by providing compressive stress during thermal excursions. Tensile strengths of sealing layers were measured by Instron test machine. The layers were examined by electron probe microanalyzer. Crsystallization rate was increased with the amount of ZnO or $Li_2O$, and ZnO increased the sealing strength, but $Li_2O$ lowered it. Sealing mechanism was due to the formation of metal oxides, which acted as binder between copper and glass-ceramics. The nickle-plated copper seal with 10% $Li_2O$ and 30% ZnO was the most strong seal, and its sealing strength was more than 56kg/$\textrm{cm}^2$.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09b
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• pp.45-52
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• 2010

Thermal properties of geomaterial are overlooked with other geomechanical properties. The transient line-source (TLS) method is one of the most used testing methods for measuring the thermal conductivity (K) and thermal diffusivity ($\alpha$) of materials. But more recently, Transient Plane-Source method was developed to measure these. It has several advantage of comparing with TSL method, but there has not been documented application in geomaterial. A Resistance Temperature Detector is used to construct sensor. For durability of Probe, Adopt a new technique that two probes are bonded in exact matching. For standard materials, such as glycerin, and ice the measured K and a values of these materials were generally within 2-5% from the standard values in the literature. This document present to evaluate the thermal properties of geomaterials and its application was tested for varying degree of saturation using the Transient Plane Source method. The result of this study suggests that it is an comparatively accurate method for simultaneously measuring thermal conductivity and thermal diffusivity and can identify the feasibility to geomaterial.

• Journal of Korean Society of Transportation
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• v.23 no.5 s.83
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• pp.135-146
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• 2005

Up to now studies on the fusion of travel time from various detectors have been conducted based on the variance raito of the intermittent data mainly collected by GPS or probe vehicles. The fusion model based on the variance ratio of intermittent data is not suitable for the license plate recognition AVIs which can deal with vast amount of data. This study was carried out to develop the fusion model based on travel time acquired from the license plate recognition AVIs and the point detectors. In order to fuse travel time acquired from the point detectors and the license plate recognition AVIs, the optimized fusion model and the proportional fusion model were developed in this study. As a result of verification, the optimized fusion model showed the superior estimation performance. The optimized fusion model is the dynamic fusion ratio estimation model on real time base, which calculates fusion weights based on real time historic data and applies them to the current time period. The results of this study are expected to be used effectively for National Highway Traffic Management System to provide traffic information in the future. However, there should be further studies on the Proper distance for the establishment of the AVIs and the license plate matching rate according to the lanes for AVIs to be established.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.4
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• pp.515-525
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• 1998

In this paper, for both transmission and reception with single antenna system of satellite communication, dual-frequency antennas which operate simultaneously at 12.5 GHz and at 14.25 GHz are designed, constructed and measured. Also by using dual feeding structure, the problems of single-fed dual-frequency antenna such as the separation of transmitting and receiving signals and single polarization, are solved. Microstrip patch as a radiation element of dual-fed dual-frequency antenna has width and length which are the resonance lengths of the corresponding frequencies for transmission and reception, respectively. The effects of the feed line on the other frequency feeding are minimized with the optimal matching scheme for the feed lines. For solving the space problems of dual-fed two-dimensional array antennas, microstrip-line and coaxial probe feedings are used for each frequency and a two-dimensional $2\times2$ array antenna was designed and measured their characteristics. The experimental results show that errors of resonance frequencies are less than 1.44%, the return losses are less than -21 dB and the isolations between two feeding ports are less than -21 dB. The characteristics of radiation patterns of dual frequency microstrip antenna are measured and evaluated. The directivities, sidelobe levels and cross polarizations are also measured and compared with the simulations. The results show some errors due to the misalignment of coaxial probe feeding.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.4 s.119
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• pp.389-397
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• 2007

This paper proposes miniaturized broadband parasitic patch antenna. The proposed antenna consists of a probe fed reduced size main patch and U-shaped parasitic patches. The parasitic patches are incorporated to the radiating edges of the main patch to miniaturize the antenna size. The broadband impedance matching can be achieved by either E-plane or H-plane electromagnetic coupling between main patch and parasitic elements. The size of radiating elements is $18{\times}17.6\;mm^2$ and the overall dimension of designed antenna with substrate and ground plane is $25{\times}30{\times}4\;mm^3$. The fabricated antenna on a FR4 substrate shows two resonant frequencies(5.12 GHz and 6.08 GHz) with 27.3 %(1.5 GHz) fractional bandwidth at 5.5 GHz center frequency. The calculated and measured radiation patterns are almost similar to conventional patch antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.11 s.102
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• pp.1086-1098
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• 2005

Two types of small wideband antennas are proposed for UWB application. One type is small biconical structure fed by coaxial probe, which is easy to be installed on the circuit board. The other type is of planar bow-tie type fed by coplanar transmission line. Generally, the bandwidth of the latter type is significantly narrower than that of the former type. It is shown, however that the bandwidth of the latter type can be made to be comparable to that of the former, if some series inductive component is introduced in the center conductor line in the CPW transmission line by replacing some part of center line with narrower line of higher characteristic impedance. The series inductance component play an important role of neutralizing the capacitive component of the small bow-tie antenna, thereby making broadband impedance matching possible. The small planar bow-tie antenna was fabricated and experimented. The experimental results for return loss are observed to be in good agreement with simulated results. The radiation pattern is also investigated experimentally.