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A study on evaluation method for indoor guide robot
Jihan KIM,Bo-Yeong Kang,JongWoon Woo,Hyung-taek Baek 제어로봇시스템학회 2020 제어로봇시스템학회 국제학술대회 논문집 Vol.2020 No.10
As applications of service robotics has become widely broaden, necessity for evaluation method upon each particular application of service robots stands out in order to secure safe usage of service robot products and promote service robot market. With these circumstances, this study focused on developing evaluation method for guide robot particularly with 2 reasons: popularity of guide robots and functional universality. By analyzing common functions of guide robots, we developed evaluation method and criteria on indoor guide robot. Through the development process, we expect that we could develop other particular evaluation methods for specific application types on the basis of this study.
Frequency Tuning of Nanowire Resonator Using Electrostatic Spring Effect
Jihan Kwon,Jungwook Choi,Kwanoh Kim,Jaesam Sim,Jinho Kim,Jongbaeg Kim IEEE 2009 IEEE transactions on magnetics Vol.45 No.5
<P>We have demonstrated resonant frequency tuning of nanowire resonator operated in both atmospheric circumstance and high vacuum environment using electrostatic spring-softening effect. The nanowire is synthesized at any desired position by focused ion beam-chemical vapor deposition (FIB-CVD) on the sidewall of batch-processed micro electrode. The resonant frequency in a vacuum chamber of 2.5 x 10(-4) Pa is 1.564 MHz under the driving voltage of 5 V-DC +/- 5 V-AC. When 30 VDC tuning bias is applied on tuning electrode, the resonant frequency is reduced to 1.529 MHz due to the electrostatic spring-softening effect while the driving bias is maintained. For the tuning bias of 60 V, the resonant frequency at atmospheric pressure has been tuned from 1.49 MHz to 1.41 MHz under the driving voltage of 30V(DC) +/- 10V(AC). The method demonstrated both in high vacuum and at atmospheric pressure is a simple and effective way to tune the deviated resonant frequency of nanowire resonator to the desired value without the alteration of the structure or post fabrication process.</P>
Kim, Hoeyeon,Lee, Sangwon,Kim, Jihan American Chemical Society 2019 Langmuir Vol.35 No.11
<P>Intracrystalline defects in metal-organic frameworks (MOFs) are known to have crucial roles in dictating their material properties. In this work, computational simulations were used to induce linker vacancy defects in MOF membranes and to investigate their influence on H<SUB>2</SUB>/CH<SUB>4</SUB> separation. Linker defective structures were created for the 228 candidate MOFs, and their separation performances were compared between the defective and the nondefective structures. Our results show that the existence of linker vacancy defects can lead to significant performance changes in the MOF membranes, and more importantly, the ranking of the best materials can differ with the defects present. This suggests the importance of taking into account the potential for defects when it comes to materials design for various membrane separation applications.</P> [FIG OMISSION]</BR>
Kim, Seon Joon,Koh, Hyeong-Jun,Ren, Chang E.,Kwon, Ohmin,Maleski, Kathleen,Cho, Soo-Yeon,Anasori, Babak,Kim, Choong-Ki,Choi, Yang-Kyu,Kim, Jihan,Gogotsi, Yury,Jung, Hee-Tae American Chemical Society 2018 ACS NANO Vol.12 No.2
<P>Achieving high sensitivity in solid-state gas sensors can allow the precise detection of chemical agents. In particular, detection of volatile organic compounds (VOCs) at the parts per billion (ppb) level is critical for the early diagnosis of diseases. To obtain high sensitivity, two requirements need to be simultaneously satisfied: (i) low electrical noise and (ii) strong signal, which existing sensor materials cannot meet. Here, we demonstrate that 2D metal carbide MXenes, which possess high metallic conductivity for low noise and a fully functionalized surface for a strong signal, greatly outperform the sensitivity of conventional semiconductor channel materials. Ti<SUB>3</SUB>C<SUB>2</SUB>T<SUB><I>x</I></SUB> MXene gas sensors exhibited a very low limit of detection of 50–100 ppb for VOC gases at room temperature. Also, the extremely low noise led to a signal-to-noise ratio 2 orders of magnitude higher than that of other 2D materials, surpassing the best sensors known. Our results provide insight in utilizing highly functionalized metallic sensing channels for developing highly sensitive sensors.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2018/ancac3.2018.12.issue-2/acsnano.7b07460/production/images/medium/nn-2017-07460z_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn7b07460'>ACS Electronic Supporting Info</A></P>
4-Methoxy-amphetamine의 효과적인 합성
김진오,이신영,김학원,김지한,이준광 경희대학교 자연과학종합연구원 2002 자연과학논문집 Vol.8 No.-
Tamsulosin, Formoterol, Fenoterol 등의 중간체로 쓰이며 그 자체로 생체적 활성을 가지고 있는 4-methoxy-amphetamine 효과적인 합성방법을 확보하였으며, Enzyme 촉매를 이용하여 키랄 환원반응을 통해 (R)-4-methoxy-amphetamine의 비대칭 합성방법을 확보하였다. The efficient synthesis of racemic 4-methoxy-amphetamine, known as the intermediate of Tamsulosin, Formoterol and Fenoterol, and showing a bioactivity by itself, has been achieved and an optically active (R)-4-methoxy-amphetamine has been synthesized through the enzymatic reduction of the ketone intermedaite.
Time-to-failure of Compressively Loaded Composite Structures Exposed to Fire
Kim, Jihan,Lee, Sung W.,Kwon, Soonwook Sage Publications 2007 Journal of composite materials Vol.41 No.22
<P>A combined thermal-structural analysis methodology based on finite element modeling is developed for the analysis of composite structures exposed to high temperatures due to fire. A simplified heat transfer model proposed by Lattimer is adopted for the thermal response model to determine temperature distributions in composite structures with and without insulation while an assumed strain solid shell finite element formulation is adopted for the structural response model with a material model that takes into account the effects of temperature on modulus and charring. Numerical analyses are carried out to determine the time-to-failure via the global buckling of simply supported and clamped wide columns of an E-glass/ vinylester woven composite material with and without insulation subjected to heat flux and compression. Large deflection non-linear analyses are also conducted to determine the displacement of the columns as the temperature changes. The beneficial effect of insulation on time-to-failure is demonstrated via numerical calculations. Sensitivity analyses are carried out to examine the effect of variation in the glass transition temperature on the time-to-failure of the composite columns.</P>