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Retrodirective RF System for Wireless Power Transfer
Wan-Su Kim,Nhut-Tan Doan,Tan-Binh Ngo,Sang-Woong Yoon 대한전자공학회 2019 대한전자공학회 학술대회 Vol.2019 No.6
This paper presents the overall wireless power transfer RF system with circulator for phase conjugating Retro-directive array (RDA). This work consists of two main parts. The former presents the Retrodirective System & Feed-forward-Cancellation (FFC) part while focus on beam of 1 x 4 RDA system & the improved transmitter (Tx) to receiver (Rx) isolation. The latter includes design of integrated circuits for power amplifier and drive amplifier. This system operates with Tx frequency of 2.4 GHz and Rx frequency of 2.5 GHz. The beamforming accuracy and minimum sensitivity of the RF system depends on the Tx-Rx isolation characteristic of the circulator. Hence, to enhance the isolation, FFC technique is incorporated. The isolation performance at 2.4 GHz and 2.5 GHz is improved by 18 dB and 21 dB, respectively, in this work.
Yoon, Wan-Hee,Jung, Yeon-Joo,Kim, Tae-Dong,Li, Ge,Park, Byoung-Jeon,Kim, Ji-Yeon,Lee, Young-Chul,Kim, Jim-Man,Park, Jong-Il,Park, Hae-Duck,No, Zae-Sung,Lim, Kyu,Hwang, Byung-Doo,Kim, Young-S 충남대학교 암연구소 2005 암연구소 업적집 Vol.4 No.-
Gabexate mesilate (GM), a synthetic protease inhibitor, has an antiproteinase activity on various types of plasma serine proteases. However, its role on matrix metalloproteinases (MMPs) has not been identified. In this study, we investigated the effect of GM on MMPs and on the invasion and metastasis of human colon cancer cell lines and neoangiogenesis. The activities of MMPs secreted from these cells were significantly reduced by GM but unaffected by the serine protease inhibitor aprotinin. GM directly inhibited purified progelatinase A derived from T98G human glioblastoma cells. In vitro, GM significantly reduced the invasive ability of colon cancer cells but not cellular motility, whereas aprotinin affected neither. Liver metastatic ability and tumorigenic potential in nude mice were remarkably reduced on treatment with GM. Immunohistochemical analysis of GM-treated tumors in mice showed a marked increase in apoptosis and a significant reduction in tumor angiogenesis. Human umbilical vein endothelial cell proliferation, tube formation, and neoangiogenesis in the rabbit cornea and Matrigel implanted in mice were significantly inhibited by GM. These results suggest that GM is a novel inhibitor of MMPs and that it may inhibit the invasion and metastasis of human colon cancer cells by blocking MMPs and neoangiogenesis.
Characteristics of HIV-Tat Protein Transduction Domain
Yoon Jong-Sub,Jung Yong-Tae,Hong Seong-Karp,Kim Sun-Hwa,Shin Min-Chul,Lee Dong-Gun,Shin Wan-Shik,Min Woo-Sung,Paik Soon-Young The Microbiological Society of Korea 2004 The journal of microbiology Vol.42 No.4
The human immunodeficiency virus type 1 (HIV-I) Tat protein transduction domain (PTD), which contains rich arginine and lysine residues, is responsible for the highly efficient transduction of protein through the plasma membrane. In addition, it can be secreted from infected cells and has the ability to enter neighboring cells. When the PTD of Tat is fused to proteins and exogenously added to cells, the fusion protein can cross plasma membranes. Recent reports indicate that the endogenously expressed Tat fusion protein can demonstrate biodistribution of several proteins. However, intercellular transport and protein transduction have not been observed in some studies. Therefore, this study examined the intercellular transport and protein transduction of the Tat protein. The results showed no evidence of intercellular transport (biodistribution) in a cell culture. Instead, the Tat fusion peptides were found to have a significant effect on the transduction and intercellular localization properties. This suggests that the HIV-1 PTD passes through the plasma membrane in one direction.
FBAR devices for RF bandpass filter applications
Yoon, Gi-Wan,Park, Sung-Chang The Korea Institute of Information and Commucation 2001 한국정보통신학회논문지 Vol.5 No.7
본 논문에서는 압전박막 및 이들의 FBAR소자 응용에 대한 연구를 발표 한다. FBAR소자는 상부 및 하부 전극 사이에 압전체가 삽입되어 있는 공진부와 SiO2/W 이 여러층으로 적층되어 있는 음향반사층부분 크게 두 부분으로 구성되어 있다. 시뮬레이션 및 측정을 통하여 제작된 여러가지 FBAR 소자들을 평가하였다. 실험결과 우수한 삽입손실, 반사손실 및 풀질계수가 얻어졌다. 따라서 FBAR 기술은 RF 대역 필터 응용을 위해서 대단히 유망한 기술로 생각된다. In this article, piezoelectric films and their application for film bulk acoustic resonator (FBAR) devices are presented. The FBAR is composed of piezoelectric film sandwiched between top and bottom electrodes and an acoustic reflector of SiO2/W stacked multilayers. Various FBAR devices were fabricated and evaluated through simulation and measurement. The insertion loss, return loss and Q-factor were observed to be reasonably high and good. The FBAR technology seems very promising particularly for RF band filter application.
Wan Seok Song,Sung-il Yoon 한국구조생물학회 2016 Biodesign Vol.4 No.4
Flagellin constitutes the flagellar filament that provides bacteria with locomotion and allows pathogens to invade the host tissue as a virulence factor. The N-terminal and C-terminal domains of flagellin are functionally important in filament formation and are highly conserved across diverse bacterial species. In the host, the conserved flagellin of pathogenic bacteria activates the innate immune receptors, including Toll-like receptor 5 (TLR5) and NOD-like receptor C4 (NLRC4), and functions as a pathogen-associated molecular pattern that alarms the host immune system. Recently, an array of structural studies has revealed flagellin-mediated immune receptor activation mechanisms, which can provide deep insights into the development of immune-modulating vaccines and therapeutics. In this review, we explain the biological functions and structural properties of flagellin in filament formation and immune activation and describe the application of flagellin to vaccine and drug development.
Yoon, Woojin,Lee, Yonggeun,Jang, Hongje,Jang, Myungsu,Kim, Jin Sung,Lee, Hee Sung,Im, Seongil,Boo, Doo Wan,Park, Jiwoong,Ju, Sang-Yong Elsevier 2015 Carbon Vol.81 No.-
<P><B>Abstract</B></P> <P>When the width of a graphene nanoribbon (GNR) is only a few nanometers, it possesses semiconducting properties that enable various high-end electronic applications. In this study, we report that the dense and stable dispersion of a natural graphite formed using flavin mononucleotide (FMN) as a surfactant produces GNRs as small as 10nm in width. High-resolution transmission electron microscopy reveals GNRs with various widths, along with a graphene flake containing straight-edged GNRs and cuts, depending on substrate treatments. Such nanoribbon formation originates from sonochemical graphene unzipping with a one-dimensional FMN supramolecular ribbon as a template. Raman spectroscopy demonstrates the universal intensity ratio of D over D′ bands near 4, supporting formation of continuous edge defect. Thermal annealing enhances the optical contrast and van der Waals interactions of the graphene film, resulting in increased conductivity compared to the as-prepared graphene film, which is also better than that of reduced graphene oxide.</P>