• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.101-106
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• 2011

In the present paper, the phenomena of abnormal noise and vibration due to acoustic resonance of CFBC(Circulating Fluidized Bed Combustion) boiler was presented. The acoustic resonance which occurred in the gas path of CFBC boiler system was caused by coincidence of vortex shedding frequency of tube bank and acoustic natural frequency of duct and hopper. And, the phenomena of beating arose from the interference of two closed resonant waves at 66.4Hz and 70.8Hz. There are two control methods for acoustic resonance in this system. The first method is to change the vortex shedding frequency from the structural alterations on the tube bank. And the second method is to change the acoustic natural frequency of the gas path with the installation of anti-noise baffles. The second one which is relatively easy to apply, was adapted in this study. As a result, the noise and vibration level have been decreased by 41dB and 94% at 66.4Hz, respectively. And the improvement of noise and vibration at 70.8Hz was identified by sensory evaluation.

• 원예과학기술지
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• 제35권3호
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• pp.323-332
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• 2017

Homology-specific transcriptional and post-transcriptional silencing, an intrinsic mechanism of gene regulation in most eukaryotes, can be induced by anti-sense, co-suppression, or hairpin-based double-stranded RNA. Hairpin-based RNA interference (RNAi) has been applied to analyze gene function and genetically modify crops. However, RNAi vector construction usually requires high-cost cloning steps and large amounts of time, or involves methods that are protected by intellectual property rights. We describe a more effective method for generating intron-spliced RNAi constructs. To produce intron-spliced hairpin RNA, an RNAi cassette was ligated with the first intron and splicing sequences of the Brassica rapa ssp. pekinensis histone deacetylase 1 gene. This method requires a single ligation of the PCR-amplified target gene to SpeI-NcoI and SacI-BglII enzyme sites to create a gene-specific silencing construct. We named the resulting binary vector system pKHi and verified its functionality by constructing a vector to silence DIHYDROFLAVONOL 4-REDUCTASE (DFR), transforming it into tobacco plants, and confirming DFR gene-silencing via PCR, RT-qPCR, and analysis of the accumulation of small interfering RNAs. Reduction of anthocyanin biosynthesis was also confirmed by analyzing flower color of the transgenic tobacco plants. This study demonstrates that small interfering RNAs generated through the pKHi vector system can efficiently silence target genes and could be used in developing genetically modified crops.

• Journal of Microbiology and Biotechnology
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• 제19권6호
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• pp.610-615
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• 2009

As a provirus, polydnavirus has a segmented DNA genome on chromosome(s) of host wasp. It contains several genes in each segment that presumably play critical roles in regulating physiological processes of target insect parasitized by the wasp. A cysteine-rich protein 1 (CRP1) is present in the polydnavirus Cotesia plutellae bracovirus (CpBV) genome, but its expression and physiological function in Plutella xylostella parasitized by the viral host C. plutellae is not known. This CpBV-CRP1 encoding 189 amino acids with a putative signal peptide (20 residues) was persistently expressed in parasitized P. xylostella with gradual decrease at the late parasitization period. Expression of CpBV-CRP1 was tissue-specific in the fat body/epidermis and hemocyte, but not in the gut. Its physiological function was analyzed by inducing transient expression of a CpBV segment containing CpBV-CRP1 and its promoter, which caused significant reduction in hemocyte -spreading and delayed larval development. When the treated larvae were co-injected with double-stranded RNA of CpBV-CRP1, the expression of CpBV-CRP1 disappeared, whereas other genes encoded in the CpBV segment was expressed. These co-injected larvae significantly recovered the hemocyte-spreading capacity and larval development rate. This study reports that CpBV-CRP1 is expressed in P. xylostella parasitized by C. plutellae and its physiological function is to alter the host immune and developmental processes.

• Archives of Pharmacal Research
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• 제29권2호
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• pp.165-171
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• 2006

Osteoarthritis is thought to be induced by the ageing-related loss of homeostatic balance between degeneration and repair mechanism around cartilage tissue in which inflammatory mediators such as reactive oxygen species, cytokines and prostaglandins are prone to overproduction under undesirable physiological conditions. Phlorotannins are unique polyphenolic compounds bearing dibenzo-1,4-dioxin skeleton which are not found in terrestrial plants but found only in some brown algal species such as Ecklonia and Eisenia families. Phlorotanninrich extracts of Ecklonia cava including LAD103 showed significant antioxidant activities such as DPPH radical scavenging, ferric ion reduction, peroxynitrite scavenging, and inhibition of LDL oxidation, indicating their possible antioxidative interference both in onset and downstream consequences of osteoarthritis. LAD103 also showed significant down regulation of $PGE_2$ generation in LPS-treated RAW 246.7 cells, and significant inhibition of human recombinant interleukin-$1{\alpha}$-induced proteoglycan degradation, indicating its beneficial involvement in pathophysiological consequences of osteoarthritis, the mechanism of which needs further investigation. Since LAD103 showed strong therapeutic potentials in arthritic treatment through several in vitro experiments, it is highly encouraged to perform further mechanistic and efficacy studies.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.302-309
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• 2004

The transmission capacity of wireless communication systems may become dramatically high by employ multiple transmit and receive antennas with space-time coding techniques appropriate to multiple transmit antennas. For large number of transmit antennas and at high bandwidth efficiencies, the receiver may become too complex whenever correlation across transmit antennas is introduced. Reducing decoding complexity at receiver by combining array processing and space-time codes (STC) helps a communication system using STC to overcome the big obstacle that prevents it from achieving a desired high transmission rate. Multi-carrier CDMA (MC-CDMA) allows providing good performance in a channel with high inter-symbol interference. Antenna array, STC and MC-CDMA system have a similar characteristic that transmit-receive data streams are divided into sub-streams. Thus, there may be a noticeable reduction of receiver complexity when we combine them together. In this paper, the combination of array processing and STC in MC-CDMA system over slow selective-fading channel is investigated and compared with corresponding existing MC-CDMA system using STC. A refinement of this basic structure leads to a system design principle in which we have to make a trade off between transmission rate, decoding complexity, and length of spreading code to reach a given desired design goal.

• 한국인터넷방송통신학회논문지
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• 제10권3호
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• pp.159-166
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• 2010

전력선은 이미 전 세계적으로 60% 이상의 주거지에 설치되어 있기 때문에 고속의 전력선 통신을 이용하여 인터넷 액세스를 실현하는 새로운 액세스용 회선을 부설하지 않고 광대역 서비스를 제공할 수 있다. 이러한 이유로 정보화 시대에 인터넷 망이 닿지 않는 Last Mile Solution에 가장 적합한 서비스로서 전력선 통신에 대한 연구가 이루어지고 있다. 하지만, 전력선은 통신 선로가 아니고 전력을 전송하도록 설계되었기 때문에 전자파의 누설로 부근의 무선통신 시스템에 영향을 주게 된다. 본 논문에서는 기존의 무선 통신 서비스와 전력선 통신과의 간섭을 줄이기 위하여 기존의 Notch Filter보다 성능 면에서 우수한 고성능 Notch Filter 알고리즘을 제안하였다. 또한, 고성능 Notch Filter를 적용하여 임베디드 보드를 통한 Notch Filter Emulator를 구현하였다.

• 대한전자공학회논문지TC
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• 제49권7호
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• pp.48-55
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• 2012

ML디코딩이 복잡도와 전송시간이 덜 소요되는 고차 안테나의 시공간코드를 제안한다. 이 때 제안한 것이 부분간섭제거 알고리즘이다. 제안된 알고리즘은 심벌을 층(Layered)으로 구분하고 동등한 채널행렬을 만들고 그룹으로 디코딩한다. 이렇게 했을 때 전송시간과 디코딩 복잡도가 줄어들었고 성능이 비직교에 비해 좋아졌다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제11권4호
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• pp.295-301
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• 2011

A triple-band transceiver module for 2.3/2.5/3.5 GHz mobile WiMAX, IEEE 802.16e, applications is introduced. The suggested transceiver module consists of RFIC, reconfigurable/multi-resonance MIMO antenna, embedded PCB, mobile WiMAX base band, memory and channel selection front-end module. The RFIC is fabricated in $0.13{\mu}m$ RF CMOS process and has 3.5 dB noise figure(NF) of receiver and 1 dBm maximum power of transmitter with 68-pin QFN package, $8{\times}8\;mm^2$ area. The area reduction of transceiver module is achieved by using embedded PCB which decreases area by 9% of the area of transceiver module with normal PCB. The developed triple-band mobile WiMAX transceiver module is tested by performing radio conformance test(RCT) and measuring carrier to interference plus noise ratio (CINR) and received signal strength indication (RSSI) in each 2.3/2.5/3.5 GHz frequency.

• Journal of electromagnetic engineering and science
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• 제11권4호
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• pp.304-310
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• 2011

The application of time-domain methods in emission measurement instruments allows for a reduction in scan time by several orders of magnitude and for new evaluation methods to be realized such as the real-time spectrogram to characterize transient emissions. In this paper two novel systems for time-domain EMI measurements above 1 GHz are presented. The first system combines ultra-fast analog-to-digital-conversion and real-time digital signal processing on a field-programmable-gate-array (FPGA) with ultra-broadband multi-stage down-conversion to enable measurements in the range from 10 Hz to 26 GHz with high sensitivity and full-compliance with the requirements of CISPR 16-1-1. The required IF bandwidths were added to allow for measurements according to MIL-461F and DO-160F. The second system realizes a system of time-interleaved analog-to-digital converters (ADCs) and has an upper bandwidth limit of 4 GHz. With the implementation of an automatic mismatch calibration, the system fulfills CISPR 16-1-1 dynamic range requirements. Measurements of the radiated emissions of electronic consumer devices and household appliances like the non-stationary emissions of a microwave oven are presented. A measurement of a personal computer's conducted emissions on a power supply line according to DO-160F is given.

• Wind and Structures
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• 제6권1호
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• pp.53-70
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• 2003

Tsing Ma Bridge in Hong Kong is the longest suspension bridge in the world carrying both highway and railway. It has two H-shape concrete towers, each of which is composed of two reinforced concrete legs and four deep transverse prestressed concrete beams. A series of wind tunnel tests have been performed to measure the aerodynamic coefficients of the tower legs and transverse beams in various arrangements. A 1:100 scaled 3D rigid model of the full bridge tower assembled from various tower components has been constructed for different test cases. The aerodynamic coefficients of the lower and upper segments of the windward and leeward tower legs and those of the transverse beams at different levels, with and without the dummy bridge deck model, were measured as a function of yaw wind angle. The effects of wind interference among the tower components and the influence of the bridge deck on the tower aerodynamic coefficients were also investigated. The results achieved can be used as the pertinent data for the comparison of the computed and field-measured fully coupled buffeting responses of the entire bridge under yaw winds.