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0.2 ${\mu}m$ Wide-Head T-Gate PHEMT 제작에 관한 연구
전병철,윤용순,박현창,박형무,이진구,Jeon, Byeong-Cheol,Yun, Yong-Sun,Park, Hyeon-Chang,Park, Hyeong-Mu,Lee, Jin-Gu 대한전자공학회 2002 電子工學會論文誌-SD (Semiconductor and devices) Vol.39 No.1
본 논문에서는 서로 다른 dose를 갖는 이중 노광 방법을 사용한 전자빔 묘화 방법을 이용하여 0.2 ㎛의 wide-head T-게이트를 갖는 PHEMT를 제작하였다. 0.2 ㎛의 게이트 길이와 1.3 ㎛의 게이트 머리의 크기를 갖는 wide-head T-게이트를 형성하기 위하여 PMMA/P(MMA-MAA)/PMMA의 3층 레지스트 구조를 사용하였다. 0.2 ㎛의 게이트 길이와 80 ㎛의 단위 게이트 폭 및 4개의 게이트 핑거를 갖는 PHEMT의 DC 특성으로 323 ㎃/㎜의 드레인 전류 밀도 및 232 mS/㎜의 최대 전달 컨덕턴스를 얻었다. 또한 동일한 소자의 RF 특성으로 40 ㎓에서 2.91 ㏈의 S/sub 21/ 이득과 11.42 ㏈의 MAG를 얻었으며, 전 이득 차단 주파수와 최대 공진 주파수는 각각 63 ㎓와 150 ㎓였다. n this paper, we have fabricated pseudomorphic high electron mobility transistors (PHEMT) with a 0.2 ${\mu}{\textrm}{m}$ wide-head T-shaped gate using electron beam lithography by a dose split method. To make the T-shape gate with gate length of 0.2 ${\mu}{\textrm}{m}$ and gate head size of 1.3 ${\mu}{\textrm}{m}$ we have used triple layer resist structure of PMMA/P(MMA-MAA)/PMMA. The DC characteristics of PHEMT, which has 0.2 ${\mu}{\textrm}{m}$ of gate length, 80 ${\mu}{\textrm}{m}$ of unit gate width and 4 gate fingers, are drain current density of 323 ㎃/mm and maximum transconductance 232 mS/mm at $V_{gs}$ = -1.2V and $V_{ds}$ = 3V. The RF characteristics of the same device are 2.91㏈ of S21 gain and 11.42㏈ of MAG at 40GHz. The current gain cut-off frequency is 63GHz and maximum oscillation frequency is 150GHz, respectively.ively.
이정우,김두형,이무하,전광인 三陟大學校 2003 論文集 Vol.36 No.-
This paper presents dynamics of spreader suspended by four flexible cables. This kind of spreader is widely used in dock side container terminals. To derive dynamic equations with Lagrange method, we derive gravitational energy of spreader and elastic energy of suspension cables. The dynamics of spreader is found to be lightly coupled with planar motion and rotational motion. With the dynamic equations, natural frequency of spreader motion is compared with the previous researches, and the results are proven to be more accurate. Simulation of spreader with and without external disturbance are shown.
김석현,남윤수,유능수,이정완,박무열,박해균,김태형 江原大學校 産業技術硏究所 2005 産業技術硏究 Vol.25 No.A
A vibration monitoring system for a small class of wind turbine (W/T) is established and operated. The monitoring system consists of monolithic integrated chip accelerometer for vibration monitoring, anemometers for wind data acquisition and auxiliary sensors for atmospheric data. Using the monitoring system, vibration response of a 6kW W/T generator is investigated. Acceleration data of the W/T tower under various operation condition is acquired in real time using LabVIEW and is remotely transferred from the test site to the laboratory in school by internet. Vibration state of the tower structure is diagnosed within the operating speed range. Resonance frequency range of the test model is investigated with the wind speed data of the test site.
자외선 B 조사가 정상 인체 멜라닌세포의 유전자 발현에 미치는 영향
김형섭 ( Kim Hyeong Seob ),박현호 ( Park Hyeon Ho ),이무형 ( Lee Mu Hyeong ) 대한피부과학회 2003 대한피부과학회지 Vol.41 No.12
N/A Background: Irradiation of the skin with ultraviolet rays result in alterations of immune reponse as well as melanogenesis and melanocarcinogenensis. These effects are largely mediated by soulble mediators released from epidermal cells in response to ultraviolet rays. Objective: To evaluate the effect of ultraviolet B (UVB) irradiation on the normal human mela-noyte gene expression. Methods: We demonstrated genes modulated by UVB irradiation among over 300 genes coding CO_s cytokins, growth factors, and growth factor receptors in normal human melanocytes by _cDNA microarray technique. Results: Two genes out of 384 genes in cultured normal human melanocytes were found up-regulated following UVB irradiation. They are the genes coding lactotransferrin and CD160. Forty one genes out of 384 genes were found down-regulated by UVB irradiation. They included the genes coding IL-9, IL-5, TNF-β, IL-6 receptor and CD20. Conclusion: These results provide the basis for future studies on the immunologic fole in modulated genes by UV-stressed human melanocytes. (Korean J Dermatol 2003;41(12):1597~1602)
Ham, Hyeong Taek,Choi, Yeong Suk,Chee, Mu Guen,Chung, In Jae Wiley Subscription Services, Inc., A Wiley Company 2006 Journal of polymer science Part A, Polymer chemist Vol.44 No.1
<P>This work is to make carbon nanotubes dispersible in both water and organic solvents without oxidation and cutting nanotube threads. Polystyrene-singlewall carbon nanotube (PS-SWNT) composites were prepared with three different methods: miniemulsion polymerization, conventional emulsion polymerization, and mixing SWNT with PS latex. The two factors, crosslinking and surface coverage of PS are important factors for the mechanical and electrical properties, including dispersion states of SWNT in various solvents. The PS-SWNT composite prepared via a conventional emulsion polymerization showed SWNT bundles entirely covered with PS, whereas the PS-SWNT composite prepared via a miniemulsion polymerization showed SWNT partially covered with crosslinked PS nanoparticles. The method of mixing SWNTs with PS latex did not show the well dispersed state of carbon nanotubes because PS was not crosslinked and was dissolved in a solvent, and nanotubes separated from PS precipitated. So the PS nanoparticle-SWNT composite had lower electrical resistance, and higher mechanical strength than the other composites made by the latter two methods. As the amount of SWNT increases, the bare surface area of SWNT increases and the electrical conductivity increases in the composite made by the miniemulsion polymerization. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 573–584, 2006</P> <B>Graphic Abstract</B> <P>Singlewall carbon nanotubes covered with polystyrene nanoparticles were prepared via in-situ miniemulsion polymerization. Polystyrene nanoparticles were attached on the surface of singlewall carbon nanotubes. The nanoparticles partially covered the sidewall of carbon nanotubes. The bare surface of singlewall carbon nanotubes and polystyrene nanoparticle attached singlewall carbon nanotubes were coexisted. Polystyrene-singlewall carbon nanotube composites were prepared with three different methods: miniemulsion polymerization, conventional emulsion polymerization, and mixing SWNT with PS latex. Their structural difference and properties were examined. <img src='wiley_img/0887624X-2006-44-1-POLA21185-gra001.gif' alt='wiley_img/0887624X-2006-44-1-POLA21185-gra001'> </P>
핵연료 피복관 HT9강의 미세조직 및 기계적 특성에 미치는 시효 효과
허형민 ( Hyeong Min Heo ),박상규 ( Sang Gyu Park ),김준환 ( Jun Hwan Kim ),김성호 ( Sung Ho Kim ),허무영 ( Mu Young Heo ) 대한금속재료학회(구 대한금속학회) 2015 대한금속·재료학회지 Vol.53 No.3
The effect of aging heat treatment was investigated in a HT9 steel for the Sodium-cooled Fast Reactor (SFR) fuel cladding tube. Aging heat treatment was carried out at 660℃ for up to 7000 hours and then microstructural analysis and mechanical tests, namely tensile and vickers hardness tests, were performed. The results showed that size of the carbide and lath were increased after aging, while the size of the prior austenite grain was not changed. Both the strength and hardness were decreased with aging, and these tendencies were similarly represented after the 3000 hours of aging. Based on the experimental results, the tempering parameter was modified and discussed with aging conditions.(Received May 16, 2014)
Effects of Cinnamaldehyde on Salivary Gland Tissue in Xerostomia Model
Choi, Ja-Hyeong,Lee, Jung-Hwa,Kim, Yeon-Hwa,Hyun, Kyung-Yae,Park, Chung-Mu,Lee, Min-Kyung 대한의생명과학회 2020 Biomedical Science Letters Vol.26 No.2
Xerostomia is a relatively common oral disease that causes various problems such as pain, discomforted, tissue damage, and infection. When the activity of AQPs, which plays an important role in the microbial channel transmembrane activity in tissues, decreases saliva secretion and the oral cavity dryness occurs. In this study, we observed whether there was a change in tissue through the expression level of AQP-5 in the submandibular gland in the 4-DAMP-induced xerostomia model. First, in order to construct a xerostomia model, 4-DAMP (1 mg/kg) and 20% urethane (0.5 mL/kg) were administered intraperitoneal (i.p.) to experimental animals. To observe the changes in the submandibular gland was excised, H&E staining was performed and protein quantitation analysis was performed using the submandibular tissue to observe the changes in AQP5 protein expression involved in changes in saliva secretion. Also, cinnamaldehyde (5, 12.5, 25 and 50 mg/kg) dissolved in 20% DMSO, in distilled water for each concentration, and then orally administered at a dose of 1 mL for biopsy and protein quantitative analysis. As a result, it was observed that the submandibular tissue, a model of xerostomia was wider than the naïve group. And then western blot analysis, the expression level of AQP5 decreased in the 4-DAMP group compared to the naïve group, and the expression increased in the group administered orally with cinnamaldehyde. Therefore, administration of 4-DAMP resulted in histological changes for xerostomia, and cinnamaldehyde would be a material that can be developed by reducing xerostomia.