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Study on the Characteristics of the Responses of Gas Sensor Modified by LB Method
Kwon, Young-Soo,Chang, Sang-Mok,Choi, Yong-Sung 동아대학교 공과대학 부설 한국자원개발연구소 1993 硏究報告 Vol.17 No.1
It was attempted to investigate the reaction of LB biological membrane in the gas surrounding by the use of LB method. The performance of the experiment was based on the idea that the adhesion of gas molecular on the surface of LB membrane, which induces the change of electrical properties, may make it possible to develop various sensor system modified from the sensor organs. The experimental results showed that for the acetone gas, the frequency changes in the proportional to the concentration of the gas. The reproducibility of the gas reaction vs. frequency change was obtained.
Synthesis of a Graphene-Like Nanofilm from Polyacrylonitrile
Kwon, Ho-Je,Jung, Chan-Hee,Ha, Jun Mok,Cho, Sung Oh,Choi, Jae-Hak American Scientific Publishers 2017 Journal of nanoscience and nanotechnology Vol.17 No.4
<P>There are various different approaches in synthesizing graphene including chemical vapor deposition (CVD) and solid-phase method, where gas or solid type carbon source, to be converted into graphene, interacts with transition metals such as nickel and copper. When any thin nickel layer coated atop the polyacrylonitrile (PAN) film is pyrolyzed at a sufficiently high temperature, it is impossible to grow a continuous graphene film with a large area owing to dewetting, which has restricted the subsequent utilization in practical applications. Herein, we suggest a method to synthesize a continuous graphene-like nanofilm with a nickel coated thin PAN film through pyrolysis at 750 to 800 degrees C in a high-vacuum furnace without a reductive gas flow. The graphene-like nanofilm obtained was characterized using Raman spectroscopy, Raman mapping, field-emission scanning electron microscopy, X-ray photoelectron spectroscopy, and field-emission transmission electron microscopy.</P>
Development and Research of Odorant Sensor by using Lipid-coated Quartz Crystals
Kwon, Young-Soo,Chang, Sang-Mok 동아대학교 공과대학 부설 한국자원개발연구소 1993 硏究報告 Vol.17 No.1
At-cut quartz crystal has been applied as chemical vapour sensors. The responses of quartz crystal at 9 MHz coated with phosphatidylglycerol(PG), phosphatidylinositol(PI), phosphatidylethanolamine(PE), phosphatidylserine(PS), and lipid A(LA) were determined for amyl acetate, acetoin, menthone and other organic gases, which showed different affinities for each lipid. The identification of odorants depending on the species of lipid used for coating is discussed in terms of the normalized resonant frequency shift pattern.
Mok, Il-Kyoon,Lee, Jae Kwon,Kim, Jeong Hwa,Pan, Cheol-Ho,Kim, Sang Min Elsevier 2018 Food chemistry Vol.258 No.-
<P><B>Abstract</B></P> <P>Our previous study reported the improved stability of fucoxanthin (FX) fortified in whole milk (WM) and skimmed milk (SM). In this study, <I>in vivo</I> and <I>in vitro</I> FX bioavailability were investigated using FX-fortified milk (FX-SM and FX-WM) and microalga <I>Phaeodactylum tricornutum</I> biomass (Pt-powder). Organ tissue accumulation of FX and its metabolites (FXOH: fucoxanthinol, AXA: amarouciaxanthin A) after repeated oral administration was in the following order: FX-SM > FX-WM > Pt-powder. <I>In vivo</I> pharmacokinetic study with a single oral administration also demonstrated that the absorption of FXOH and AXA was the highest for FX-SM. To reinforce the <I>in vivo</I> results, <I>in vitro</I>-simulated digestion and Caco-2 cell uptake assays were performed, which revealed that FX-SM showed the highest FX bioaccessibility (release from food matrices) and cellular uptake efficiency of FX and FXOH. In conclusion, skimmed milk was validated as an excellent food matrix for FX application in terms of stability and bioavailability.</P> <P><B>Highlights</B></P> <P> <UL> <LI> FX-SM showed the highest organ tissue accumulation and plasma absorption. </LI> <LI> Higher bioaccessibility and cellular uptake efficiency of FX-SM increased FX bioavailability. </LI> <LI> Higher protein and Ca<SUP>2+</SUP> ion and lower fat accounted for the higher bioaccessibility and cellular uptake efficiency of FX-SM. </LI> </UL> </P>
Sensorless Control Method in IPMSM Position Sensor Fault for HEV
Sung-Joo Kim,Yong-Kyun Lee,Ju-Suk Lee,Kwang-Woon Lee,Taesuk Kwon,Hyungsoo Mok 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.5
The widely used motors in HEV(Hybrid Electric Vehicles) are IPMSM(Interior Permanent Magnet Synchronous Motor) which has no rotor heat, higher efficiency and advantageous in volume and weight comparing with other motors. For vector control of IPMSM, position information of rotor is required but Resolver is mainly used as the detecting sensor. However, the use of position sensors will reduce the system reliability of hybrid electric vehicles. In this paper, a way to control the motor by sensorless was proposed at the event of sensor failure. We also implemented IPMSM sensorless operation by the expanded EMF(Electro Motive Force) voltage way and harmonic voltage which is applying in the low speed area. And we proposed how to change with sensorless control by detecting the position sensors failure and verified it through experiments.
Anisotropic superconductivity of high quality FeSe<sub>1-x</sub> Single crystal
Kwon, Chang Il,Ok, Jong Mok,Kim, Jun Sung The Korea Institute of Applied Superconductivity a 2014 한국초전도저온공학회논문지 Vol.16 No.4
We investigate the upper critical field anisotropy ${\Gamma}_H$ and the magnetic penetration depth anisotropy ${\Gamma}_{\lambda}$ of a high-quality $FeSe_{1-x}$ single crystal using angular dependent resistivity and torque magnetometry up to 14 T. High quality single crystals of $FeSe_{1-x}$ were successfully grown using $KCl-AlCl_3$ flux method, which shows a sharp superconducting transition at $T_C{\sim}9K$ and a high residual resistivity ratio of ~ 25. We found that the anisotropy ${\Gamma}_H$ near $T_C$ is a factor of two larger than found in the poor-quality crystals, indicating anisotropic 3D superconductivity of $FeSe_{1-x}$. Similar to the 1111-type Fe pnictides, the anisotropies ${\Gamma}_{\lambda}$ and ${\Gamma}_H$ show distinct temperature dependence; ${\Gamma}_H$ decreases but ${\Gamma}_{\lambda}$ increases with lowering temperature. These behaviors can be attributed to multi-band superconductivity, but different from the case of $MgB_2$. Our findings suggest that the opposite temperature dependence of ${\Gamma}_{\lambda}$ and ${\Gamma}_H$ is the common properties of Fe-based superconductors.
Kwon, Yong-Hyun,Jang, Sung Ho,Lee, Mi Young,Byun, Woo Mok,Cho, Yoon Woo,Ahn, Sang Ho 영남대학교 의과대학 2005 Yeungnam University Journal of Medicine Vol.22 No.1
뇌성마비로 인해 오른 손에서 단부전마비를 호소하는 환자를 대상으로 기능적 자기공명영상 장치와 경두개 자기 자극기를 사용하여 운동신경의 회복기전을 연구하였다. 대상자는 21세 된 남자 환자로 오른손에 경미한 운동 기능의 손상을 보였고, 자기공명영상의 소견에서 좌반구의 precentral knob에서 병변을 보였다. 기능적 자기공명영상 촬영은 한 명의 대상자와 여덟 명의 정상인을 대상으로 표준화된 헤드코일을 사용하여 1.5 T의 장치에서 BOLD 기술을 적응하여 실시하였다. 대상자들의 운동수행은 1 ㎐ 주기로 손가락의 굴곡과 신전을 반복하는 과제가 제시되었다. 경두개 자기 자극은 원형 코일을 사용하여 코일의 앞쪽 부분이 대상자의 두피에서 1 ㎝ 정도 떨어진 정접부위에 적용되었고 양측의 짧은엄지벌림근에서 발생된 운동 유발 전위가 동시에 측정되었다. 자기공명영상의 결과에서 환자의 비손상측(좌 측) 손과 정상군의 좌측 손의 운동 수행 시 오른쪽의 일차운동감각영역(SMI)의 precentral knob에서 활성도가 나타났다, 그러나, 환자의 손상측(우측) 손의 운동 수행 시, 좌측 일차운동감각영역의 손상된 precentral knob 내측 부위에서 활성도를 보였다. 또한, 경두개 자기 자극의 결과에서 손상측 짧은엄지벌림근에서 발생된 운동 유발 전위에 해당하는 뇌 부위가 환자의 정상측과 비교하여 1 ㎝ 내측에서 발견되었다. 그러므로 손상측 손의 운동 기능이 손상된 precentral knob의 내측 부분으로 전위되어 신경재구성이 이루어진 것으로 추정되는 결론을 얻었다. The motor recovery mechanism of a 21-year-old male monoparetic patient with cerebral palsy, who had complained of a mild weakness on his right hand since infancy, was examined using functional Magnetic Resonance Imaging (fMRI) and Transcranial Magnetic Stimulation (TMS). The patient showed mild motor impairment on the right hand. MRI located the main lesion on the left precentral knob of the brain. fMRI was performed on this patient as well as 8 control subjects using the Blood Oxygen Level Dependent technique at 1.5 T with a standard head coil. The motor activation task consisted of finger flexionextension exercises at 1 ㎐ cycles. TMS was carried out using a round coil. The anterior portion of the coil was applied tangentially to the scalp at a 1.0 ㎝ separation. Magnetic stimulation was carried out with the maximal output. The Motor Evoked Potentials (MEPs) from both Abductor Pollicis Brevis muscles (APB) were obtained simultaneously. fMRI revealed that the unaffected (right) primary sensori-motor cortex (SM1), which was centered on precentral knob, was activated by the hand movements of the control subjects as well as by the unaffected (left) hand movements of the patient. However, the affected(right) hand movements of the patient activated the medial portion of the injured precentral knob of the left SM1. The optimal scalp site for the affected (right) APB was located at 1 ㎝ medial to that of the unaffected (left) APB. When the optimal scalp site was stimulated, the MEP characteristics from the affected (right) APB showed a delayed latency, lower amplitude, and a distorted figure compared with that of the unaffected (left) APB. Therefore, the motor function of the affected (right) hand was shown to be reorganized in the medial portion of the injured precentral knob.