• 한국환경과학회지
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• 제27권1호
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• pp.27-38
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• 2018

This study was carried out in the Bukhan River in the summer of 2014 and 2015, to identify the relationship between geosmin and the morphological changes in Anabaena. Identification of Anabaena was conducted using morphological and molecular analyses. Anabaena in this study was similar to Anabaena circinalis, A. crass, and A. spiroides with regard to regular coils, vegetative cell, akinete shape, and size, hoever, it was distinguishabl from A. crass and A. spiroides because of its larger trichome coil size. Additionally, the sequences of phycocyanin (PC) gene from Anabaena showed a 99% genetic similarity with A. circinalis NIES-1647 strain. The coil diameter of trichome ranged from 106 to $899{\mu}m$, and the diameter and abundance showed an insignificant positive correlation (r=0.544, p<0.05). The result of relationship between the coil diameter and the cell number per 360-degree rotation was kept at $33.8{\pm}5.2$ cells per $100{\mu}m$ diameter despite variable diameter. The average geosmin concentrations in 2014 and 2015 were investigated to be 99 ng/L and 35 ng/L, respectively. A. circinalis cell density contributed considerably to the change in geosmin and was positively correlated with geosmin concentration (2014; r=0.599, p<0.01, 2015; r=0.559, p<0.01). Our results suggest that geosmin and coil diameter could be estimated with the help of cell density.

• 산업기술연구
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• 제21권B호
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• pp.125-132
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• 2001

Heat dissipation technology using flow resonant phenomenon is a kind of new concept in heat transfer area. A vibration exciter is needed to generate air turbulence which has the natural shedding frequency of heat system. A mechanical vibrating device for the air flow oscillation is introduced, which is driven by a moving coil actuator. An analytical dynamic model for this mechanical vibration exciter is presented and its' validity is verified by the comparison with experimental data. Values of some unknown system parameters in the analytic model are estimated through the system identification approach. Based on this mathematical model, the vibration exciter using strain displacement estimator is developed. And in the experiment, the feedback control is used. During the experimental verification phase, it turns out the high modal resonant characteristics of vibrating plate are the major barrier against obtaining a high bandwidth vibration exciter.

• Journal of electromagnetic engineering and science
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• 제17권4호
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• pp.233-237
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• 2017

In this paper, a dual-band high frequency (HF) and ultra-high frequency (UHF) radio-frequency identification (RFID) tag antenna is presented that operates in the 13.56 MHz band as well as in the 920 MHz band. A spiral coil along the edges of the antenna substrate is designed to handle the HF band, and a novel meander open complementary split ring resonator (MOCSRR) dipole antenna is utilized to generate the UHF band. The dual-band antenna is supported by a single-feeding port for mono-chip RFID applications. The antenna is fabricated using an FR4 substrate to verify theoretical and simulation designs, and it has compact dimensions of $80mm{\times}40mm{\times}0.8mm$. The proposed antenna also has an omnidirectional characteristic with a gain of approximately 1 dBi.

• Animal cells and systems
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• 제13권4호
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• pp.411-418
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• 2009

We are reporting the identification, expression patterns, and possible biological functions of zebrafish kif3b (kif3bz) encoding 475 amino acids. Kif3Bz contains the kinesin motor domain, catalytic domain, KISc domain, and one single coiled coil domain. Phylogenetic analysis indicates that kif3bz is a highly conserved gene among the tested vertebrates. First of all, both maternal and zygotic messages of kif3bz were evenly distributed in the blastomeres at 2-cell stage. Its ubiquitous expression throughout the blastomeres continued till 40% epiboly. However, kif3bz transcripts became restricted in Kupffer's vesicle at tailbud and 6-somite stages. At 13-somite stage, kif3bz expression pattern became specific to the telencephalon, diencephalon, trigeminal placode, and somites. Such expression patterns were further intensified in the telencephalon, diencephalons, hind brain, pronephric ducts, optic vesicles, and spinal cord neurons in the 23-somite stage embryos, and last till 24 hpf. We discussed possible functions of Kif3Bz related to the vertebrate embryonic development.

• Journal of Magnetics
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• 제21권1호
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• pp.57-60
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• 2016

Non Destructive Testing (NDT) methods that are capable of detecting the wall thinning and defects through insulation and cladding sheets are necessary. In this study we developed a Pulsed Eddy Current (PEC) system to detect wall thinning of ferro magnetic steel pipes covered with 95 mm thick fiber glass thermal insulator and shielded with aluminum plate of thickness 0.4 mm. In order to confirm the thickness change due to wall thinning, two different sensors, a hall sensor and a search coil sensor were used as a detecting element. In both the cases, the experimental data indicates a considerable change in the detected pulse corresponding to the change in sample thickness. The thickness of the tube was made to change such as 2.5 mm, 5 mm and 8 mm from the inner surface to simulate wall thinning. Fast Fourier Transform (FFT) was calculated using window approach and the results were summarized which shows a clear identification of thickness change in the test specimen by comparing the magnitude spectra.

• 수산해양기술연구
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• 제33권3호
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• pp.183-188
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• 1997

어종의 식별을 위한 음향학적 정보를 추출해 내는 데 활용하기 위한 초음파 변환기를 설계하기 위한 시도의 하나로꺼 전극분할 원반형 압전진동자를 이용하여 공진주파기를 가변시켜 넓은 주파수 대역에 걸쳐 사용할 수 있는 어군탐지기용 송.수파기를 설계하였다. 본 연구에서 설계한 초음파 변환기는 전극분할형 압전진동자의 한쪽 전극에 발전기를 접속하고, 다른 쪽 전국에 2.7~15.0 mH 인덕턴스를 접속하였을 때, 경방향에 대한 공진 주파스는 49.5~ 55.7 kHz의 범위에서 가변시킬 수 있었고, 또한 외부에서 진동자에 인가한 임피던스의 영향에 의해 출현하는 공진주파수에는 61.3~121.7 kHz의 범위에서 가변시킬수 있었다. 그러나, 이들 주파수에 대한 전기음향효율을 고려 할때, 실제로 활용할 수 있는 주파수 범위는 이것보다 훨씬 좁은 폭이 될 것이라 판단된다.

• 마이크로전자및패키징학회지
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• 제13권3호
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• pp.9-12
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• 2006

전기도금 방법으로 유리기판 위에 제작한 코일과 영구자석을 이용하여 초소형발전기를 제작하였다. 여러 크기의 코일 구조를 설계한 마스크를 제작하고, 이를 이용하여 MEMS 코일을 제작하였다. 그 중 두께가 $7{\mu}m$ 선폭이 $20{\mu}m$ 길이가 1.6 m인 코일을 선택하여 실험하였다. 광학현미경과 SEM을 사용하여 제작된 코일의 구조를 분석하였다. 또한 모터의 회전운동을 진동운동과 유사한 선형운동으로 변환하는 진동발생시스템을 제작하였고, 자석과 코일을 진동발생장치에 설치하고 진동을 발생시키면 교류 전압이 발생한다. 0.5Hz에서 8Hz까지 진동주파수를 변화시켜 특성을 측정하였다. 발생된 전압은 3Hz에서 106mV가 발생하였고, 6Hz에서 198mV가 발생하였다. 본 연구의 목적은 쓸모없이 버려지는 진동에너지를 유용한 전기에너지로 변환하는 초소형발전기 소자를 제작하는 것이다.

• 대한기계학회논문집A
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• 제26권9호
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• pp.1874-1881
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• 2002

Heat dissipation technology using the flow resonant phenomenon is a kind of a new concept in the heat transfer area. A vibration exciter is needed to enhance air flow mixing which has the natural shedding frequency of thermal system. A mechanical vibrating device for the air flow oscillation is introduced, which is driven by a moving coil actuator with a displacement estimator using strain gage. An analytical dynamic model for this mechanical vibration exciter is presented and its validity is checked by the comparison with experimental data. Values of some unknown system parameters in the analytic model are estimated through the system identification approach. Based on this mathematical model, the vibration exciter using strain displacement estimator is developed. During the experimental verification phase, it turns out the high modal resonant characteristics of a vibrating plate are a major barrier against obtaining a high bandwidth vibration exciter.

• 마이크로전자및패키징학회지
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• 제14권4호
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• pp.57-61
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• 2007

PCB제작방법으로 제작한 4층 사각코일과 Nd 영구자석을 이용하여 초소형발전기를 제작하였다. 선폭이 $100{\mu}m$로 제작된 4층 사각코일의 크기는 두께가 1.6 mm 면적이 $1{\times}1cm^2$ 와 $2{\times}2cm^2$이다. 진동발생장치를 제작하고 코일위에서 Nd 영구자석을 수평으로 움직여 교류전압을 발생시켰다. 진동수를 0.5 Hz에서 7 Hz까지 변화시키면서 전압 값을 측정하였다. 5.5 Hz의 진동을 발생시켜 $1{\times}1cm^2$의 크기의 코일에서 62 mV의 교류전압이 발생하였고 $2{\times}2cm^2$의 크기의 코일에서 245 mV의 교류전압이 발생하였다. 7 Hz의 진동수에서 $2{\times}2cm^2$의 크기의 코일에서 320 mV의 교류전압이 발생하였고 채배정류회로를 이용할 때는 7 Hz의 진동수에서 400 mV의 직류전압이 발생하였다.

• 한국염색가공학회지
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• 제14권1호
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• pp.11-17
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• 2002

To identify the antimicrobial activity, of tumeric and its active compound tumeric was fractionated into four groups dichloromethane extract, hexane fraction, methanol soluble fraction and residue's extract. They were tested for antibacterial activity against E. coil and S. aureus and the methanol soluble fraction was found lo be the most active fraction. Compound I, II and III were isolated from TLC and silica gel column chromatography in the methanol soluble fraction. These compounds were analyzed by $^1H-NMR\;and\;^{13}C-NMR$ spectra and identified as curcumin I, II and III. They were also tested for antimicrobial activity against E. coli and S. aureus. Curcumin I was the must active curcuminoids due to the phenolic and methoxyl$(OCH_3)$ moiety in the same molecular structure.