• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.184.2-184.2
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• 2012

위성의 전장품은 전기적 접속을 위해서 1:1 연결을 하는 Point-to-Point 버스 방식과 여러개의 Slave (Remote Terminal)을 갖고, 일반적으로 1개의 Master (Controller)에 의해서 연결하게 되는 버스 구조를 갖는 접속 채널을 통해서 연결이 된다. 가장 많이 사용되는 방식인 MIL-STD-1553B는 데이터 전송속도가 1Mbps이고, Transformer에 의해서 완전하게 버스와 각 전장품이 완전하게 절연이 되는 구조로, 전기적 고장이 전달되는 것을 방지할 수가 있지만, 설계의 난이도가 높다. 고속 버스는 SpaceWire를 사용하고, 100Mbps이상의 속도를 지원할 수가 있지만, LVDS등의 고속 채널 설계 및 노이즈에 민감한 특성 때문에, 저속의 통신채널에서는 사용하기 어렵다. 저속의 데이터 채널을 위해서는 UART 방식이 사용된다. UART 방식은 RS-422 방식과 RS-485 방식이 사용되지만, 1553B 또는 SpaceWire 등과 같이 프로토콜이 정해지지 않아서, 사용자가 직접 프로토콜을 지정해야하는 문제가 있다. 또한 RS-422은 1:1 방식의 Point-to-Point UART를 위해서 사용되고, RS-485는 버스 방식의 연결을 지원할 수가 있지만, 동시에 여러개의 TX가 enable되는 경우에는 TX사이에 고장을 일으킬 수 있어서, 1번에 TX가 1개만 사용되도록 제어할 필요가 있다. 또한 RS-485방식의 버스를 구현할 경우에는 1553B처럼 와전하게 절연이 불가능하므로, 전기적이나 기능적으로 485버스에 문제가 발생할 경우에 절연과 같은 기능이 지원되도록 구현이 되어야 한다. 본 논문에서는 안정적인 485 UART버스 구현을 위한 기술에 대해서 평가하고 분석하도록 하겠다.

• ETRI Journal
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• v.36 no.3
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• pp.352-360
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• 2014

This paper presents a 900 MHz zero-IF RF transceiver for IEEE 802.15.4g Smart Utility Networks OFDM systems. The proposed RF transceiver comprises an RF front end, a Tx baseband analog circuit, an Rx baseband analog circuit, and a ${\Delta}{\Sigma}$ fractional-N frequency synthesizer. In the RF front end, re-use of a matching network reduces the chip size of the RF transceiver. Since a T/Rx switch is implemented only at the input of the low noise amplifier, the driver amplifier can deliver its output power to an antenna without any signal loss; thus, leading to a low dc power consumption. The proposed current-driven passive mixer in Rx and voltage-mode passive mixer in Tx can mitigate the IQ crosstalk problem, while maintaining 50% duty-cycle in local oscillator clocks. The overall Rx-baseband circuits can provide a voltage gain of 70 dB with a 1 dB gain control step. The proposed RF transceiver is implemented in a $0.18{\mu}$ CMOS technology and consumes 37 mA in Tx mode and 38 mA in Rx mode from a 1.8 V supply voltage. The fabricated chip shows a Tx average power of -2 dBm, a sensitivity level of -103 dBm at 100 Kbps with PER < 1%, an Rx input $P_{1dB}$ of -11 dBm, and an Rx input IP3 of -2.3 dBm.

• Journal of Satellite, Information and Communications
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• v.9 no.1
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• pp.90-96
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• 2014

This paper is about increasing transfer efficiency of wireless power transmission. The new method is proposed to detect the alignment of transmitter and receiver of wireless charger and so smart phone can display the position of wireless charging receiver on its LCD panel for the maximum charging efficiency. The previous method is only to show the transfer efficiency, but this method is to show not only the efficiency but also coordinates of receiver. The apparatus of the wireless charger is based on WPC(Wireless Power Consortium) standard and has planar air coil combined with magnet shield in Tx and Rx device so that the leakage flux is minimized on condition of under hundreds of kHz operating frequency. In this paper, it's showed that relation of magnet field and distance of each coils can be linearized and position information of Tx and Rx device is calculated thru trigonometry. Through the experiment, the obstacles of linearity are discovered and also showed that it can be optimized. and so the presented method is suitable for alignment detection method of Tx and Rx device in WPC wireless charger.

• Bulletin of the Korean Chemical Society
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• v.10 no.4
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• pp.357-359
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• 1989

The ion aggregates formed between cationic triphenylmethane dyes and tetraphenylborate(TPB) or tetrakis(4-fluorophenyl) borate (TFB) anions have been investigated spectroscopically. The photometric sensitivities of the dyes are found to be increasing in the order pararosaniline < malachite green < methyl violet 2B < crystal violet < ethyl violet. Cetyltrimethylammonium bromide(CTAB) and Triton X-100(TX-100) destroy the ion aggregates. By comparing the concentration of surfactant beyond which dye-borate mixed solutions behave identically with the dye blank, the order of hydrophobicity appears to be parallel with that of photometric sensitivity.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.6
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• pp.959-968
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• 2000

In this paper, a low phase noise frequency synthesizer used to TX local oscillator in BWLL RF tranceiver is presented. The phase-locked stable 25GHz-band frequencies in BWLL TX LO are obtained by using 2 GHz baseband frequency synthesizer, sixth-harmonic frequency multiplier and frequency doubler at 12 GHz band frequency input. The 25 GHz band frequency synthesizer presented in this paper has 3-output frequencies at 24.92 GHz, 25.10 GHz, 25.26 GHz. At 24.92 GHz frequency the synthesizer has 0.44 dBm output power and shows -87.93 dBc/Hz(a 10 KHz), -109.54 dBc/Hz (a100 KHz) phase noise characteristics .

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.4
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• pp.1048-1058
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• 1996

In this paper, a small duplexer is designed and implemented using a H-plane T-junction and Transmitting/Geceiving filte with a dual mode cavity resonator for Ku-band. Transmitting(TX) filter is designed at center frequeny 12.5 GHz and Receiving(RX) filter, at center frequency 14.5 GHz. Both filters have a 100 MHz bandwidth. This duplexer is reduced to about 40% by the conventional duplexer of cavity bandpass filter structure in size. Operating characteristics of duplexer is optimized in order not to distors matching characteristics of each filter when interfaced to a H-plane T-junction. Consequently, the responses of filter with H-plane T-junction nearly coincide with that of filter itself.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.3
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• pp.38-46
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• 1996

The purpose of this study is to develop the miniaturized duplexer filter for mobile communications using high dielectric constant (${\varepsilon}$r > 100, 180) ceramic resonators. Duplexer filter was ocmposed of ceramic resonators which has been developed using BNT system and SCT system, respectively. Developed duplexer filter was formed to have Tx frequency band at 836.5 (($\pm$12.5)MHz and Rx frequency band at 881.5 ($\pm$12.5)MHz. Insertion loss at Tx frequency band was 1.41dB and 1.46dB, insertion loss at Rx frequency band was 3.49dB and 3.65dB, respectively. Especially, duplexer filters using dielectric cermaics with ${\varepsilon}$r = 180 were 8% smaller than commercially manufactured duplexer filters using dielectric ceramics with ${\varepsilon}$r = 90 by murata.

• Korean Journal of Microbiology
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• v.41 no.4
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• pp.262-268
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• 2005

Intoxication of murine macrophages (RAW 264.7) with the anthrax lethal toxin (LeTx 100 ng/ml) results in profound alterations in the host cell gene expression. The role of LeTx in mediating these effects is unknown, largely due to the difficulty in identifying and assigning function to individual proteins. In this study, we have used two-dimensional polyacrylamide gel electrophoresis to analyze the protein profile of murine macrophages treated with the LeTx, and have coupled this to protein identification using MALDI-TOF mass spectrometry. Interpretation of the peptide mass fingerprint data has relied primarily on the ProFound database. Among the differentially expressed spots, cleaved mitogen-activated protein kinase kinase (Mek1) and glucose-6-phosphate dehydrogenase were increased in the LeTx treated macrophages. Mek1 acts as a negative element in the signal transduction pathway, and G6PD plays the role for the protection of the cells from the hyper-production of active oxygen. Our results suggest that this proteomic approach is a useful tool to study protein expression in intoxicated macrophages and will contribute to the identification of a putative substrate for LeTx.

• Journal of electromagnetic engineering and science
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• v.9 no.3
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• pp.130-140
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• 2009

The design theory and experimental results of a true random noise radar system are presented in this paper. Target range information can be extracted precisely by correlation processing between the delayed reference and the signal received from a target, and the velocity information by the Doppler processing with successive correlation data. A K-band noise radar system was designed using random FM noise signal, and the characteristics of the fabricated system were examined with laboratory and outdoor experiments. A C-band random FM noise signal was generated by applying a low-frequency white Gaussian noise source to VCO(Voltage Controlled Oscillator), and a K-band Tx noise signal with 100 MHz bandwidth was obtained by using a following frequency multiplier. Two modified wave-guide horn arrays were designed and fabricated, and used for the Tx and Rx antennas. The required amount of Tx/Rx isolation was attained by using a coupling cancellation circuit as well as keeping them apart with predetermined spacing. A double down-conversion scheme was used in the Rx and reference channels, respectively, for easy post processing such as correlation and Doppler processing. The implemented noise radar performance was examined with a moving bicycle and a very high-speed target with a velocity of 150 m/s. The results extracted by the Matlab simulation using the logging data were found to be in a reasonable agreement with the expected results.

• Textile Coloration and Finishing
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• v.19 no.1 s.92
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• pp.31-36
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• 2007

There are several factors in the degradation of textiles. The crucial factors in textile weakening are humidity, dust, smoke, sunlight, microorganisms and so on. Especially silk fabrics are more susceptible to microorganisms than other fabrics, because they are mainly consisted of proteins. In this study, we investigated the activities for degrading casein and silk fibers with 2 strains, Bacillus cereus TX1 and Pseudomonas fluorescens TX 2, isolated from domestic museums. They were compared to those of standard control strains, Klebsiella pneumoniae and Staphylococcus aureus, usually used for the antibiotic test of fabrics. The caseinolytic activities of K. pneumoniae and S. aureus were higher than those of isolated strains. But in the cases of silk fiber degrading, B. cereus TX 1 showed the highest activity on both silk 1 and silk 2. Therefore, caseinolytic activities were not coincident with the activity to degrade silk fibers. All strains degraded silk 1(strength retention 100%) better than silk 2(strength retention 50%). It means that bacteria mainly participate in the early stage of degrading silk fabrics, but as time goes by, the importance of bacteria for degrading silk fabrics would decreased. Even though the importance of bacteria may decrease, controlling bacterial activity is necessary to preserve historic silk fabrics.