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Design of Full Band UWB Common-Gate LNA
Yuna Shim,Chang-Wan Kim,Jeongseon Lee,Sang-Gug Lee IEEE 2007 IEEE microwave and wireless components letters Vol.17 No.10
<P>A two-stage, common-gate in cascade with cascode, ultra wideband low noise amplifier (LNA) topology is proposed for 3.1 to 10.5 GHz full band application. The common-gate first stage is adopted and optimized for low noise figure (NF) at high frequencies. The LNA implemented in 0.18 mum CMOS shows more than 10 dB input return loss, maximum gain of 16 dB, and NF of 3.8~4.0 dB over the full frequency band while dissipating 5.3 mA from 1.8 V supply.</P>
Low Noise RF Front-End for UWB applications
Yuna shim,Won Ki Park,Min Kyoung Won,Sung chel Lee,Hang Sun Son,Kang Min Seok,Sang Gug Lee 대한전자공학회 2009 ITC-CSCC :International Technical Conference on Ci Vol.2009 No.7
Proposed RF Front-End provides low noise performance in UWB application. 2 stage common gate and common source stage shows low noise, wide input matching and widely flat gain response. With simple single balanced mixer the total conversion gain is 16㏈, input matching is under -10㏈. The SSB noise figure is merely 2.7~3㏈ in 7~10㎓ frequency range. The RF Front-End is implemented by 0.13㎛ CMOS technology. The total power consumption is 11㎃/1.2V.
Simultaneous noise and input matched ultra wide band LNA design
Shim, Yuna,Kim, Chang-Wan,Lee, Sang-Gug Wiley Subscription Services, Inc., A Wiley Company 2007 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.49 No.9
<P>Proposed a low noise amplifier (LNA) design technique that satisfies simultaneous noise and input matched condition over ultra wide band (UWB) frequency range. Simultaneously, noise- and input-matched UWB LNA is implemented in 0.18 μm CMOS technology, and measurements show higher than 8 dB of input return loss, maximum gain of 10.5 dB, and noise figure of 3.9–6 dB over 2–4 GHz while dissipating 4 mA from a 1.8-V supply. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2275–2279, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22650</P>
Shim, Su Yong,Choi, Yuna,Ryu, Do Hyun American Chemical Society 2018 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.140 No.36
<P>Chiral Lewis acid catalyzed asymmetric formation of cyclobutanones from α-silyloxyacroleins and α-alkyl or α-aryl diazoesters has been developed. In the presence of a chiral oxazaborolidinium ion catalyst, various α-silyloxycyclobutanones possessing a chiral β-quaternary center were synthesized in high yield (up to 91%) with excellent enantio- and diastereoselectivity (up to 98% ee and up to >20:1 dr) through tandem cyclopropanation/semipinacol rearrangement. The synthetic potential of this method was illustrated by conversion of the product to various cyclic compounds such as γ-lactone, cyclobutanol, and cyclopentanone.</P> [FIG OMISSION]</BR>
Development of implant loading device for animal study about various loading protocol: a pilot study
Joon-Ho Yoon,Young-Bum Park,Yuna Cho,Chang-Sung Kim,Seong-Ho Choi,Hong-Seok Moon,Keun-Woo Lee,June-Sung Shim 대한치과보철학회 2012 The Journal of Advanced Prosthodontics Vol.4 No.4
PURPOSE. The aims of this pilot study were to introduce implant loading devices designed for animal study and to evaluate the validity of the load transmission ability of the loading devices. MATERIALS AND METHODS. Implant loading devices were specially designed and fabricated with two implant abutments and cast metal bars, and orthodontic expansion screw. In six Beagles, all premolars were extracted and two implants were placed in each side of the mandibles. The loading device was inserted two weeks after the implant placement. According to the loading protocol, the load was applied to the implants with different time and method,simulating early,progressive,and delayed loading. The implants were clinically evaluated and the loading devices were removed and replaced to the master cast, followed by stress-strain analysis. Descriptive statistics of remained strain (με) was evaluated after repeating three cycles of the loading device activation. Statistic analysis was performed using nonparametric, independent t-test with 5% significance level and Friedman's test was also used for verification. RESULTS. The loading devices were in good action. However, four implants in three Beagles showed loss of osseointegration. In stress-strain analysis, loading devices showed similar amount of increase in the remained strain after applying 1-unit load for three times. CONCLUSION. Specialized design of the implant loading device was introduced. The loading device applied similar amount of loads near the implant after each 1-unit loading. However, the direction of the loads was not parallel to the long axis of the implants as predicted before the study.