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Variation of Conductivity of Poly(ethylene oxide)Electrolytes with Lithium Salts and Plasticizers
Seong-In Moon,Jong-Uk Kim,Bong-Soo Jin,Hal-Bon Gu,Mun-Soo Yun 전력전자학회 1995 ICPE(ISPE)논문집 Vol.1995 No.10
The purpose of this study is to research and develop solid polymer electrolyte (SPE) for Li secondary battery. We investigated the effects of lithium salts, plasticizer addition, temperature dependence of conductivity, electrochemical stability window and impedance spectroscopy of polyethylene oxide(PEO) electrolytes. PEO electrolyte complexed with LiCIO_4 showed the better conductivity than the others. PEO-LiCIO_4 electrolyte, when EO/Li ratio is 8, showed the highest conductivity. By adding propylene carbonate and ethylene carbonate to PEO-LiCIO_4 electrolyte, its conductivity was higher than PEO-LiCIO_4 without those. Also PEO_8LiCIO_4PC3EC5 electrolyte remains stable up to 4.5V.
( Seong Ho Kim ),( Jun Hwa Song ),( Hyun Il Mun ),( Keon Uk Park ) 대한내과학회 2009 The Korean Journal of Internal Medicine Vol.24 No.2
Background/Aims: Acidic saline injections produce mechanical hyperresponsiveness in male Sprague-Dawley rats. We investigated the effect of milnacipran in conjunction with tramadol on the pain threshold in an acidic saline animal model of pain. Methods: The left gastrocnemius muscle of 20 male rats was injected with 100 μL of saline at pH 4.0 under brief isoflurane anesthesia on days 0 and 5. Rats administered acidic saline injections were separated into four study subgroups. After determining the pre-drug pain threshold, rats were injected intraperitoneally with one of the following regimens; saline, milnacipran alone (60 mg/kg), milnacipran (40 mg/kg) plus tramadol (20 mg/kg), or milnacipran (40 mg/kg) plus tramadol (40 mg/kg). Paw withdrawal in response to pressure was measured at 30 min, 120 min, and 5 days after injection. Nociceptive thresholds, expressed in grams, were measured with a Dynamic Plantar Aesthesiometer (Ugo Basile, Italy) by applying increasing pressure to the right or left hind paw until the rat withdrew the paw. Results: A potent antihyperalgesic effect was observed when tramadol and milnacipran were used in combination (injected paw, p=0.001; contralateral paw, p=0.012). This finding was observed only at 30 min after the combination treatment. Conclusions: We observed potentiation of the antihyperalgesic effect when milnacipran and tramadol were administered in combination in an animal model of fibromyalgia. Further research is required to determine the efficacy of various combination treatments in fibromyalgia in humans. (Korean J Intern Med 2009;24:139-142)
Design of Brushless DC Motor Controller for an Electric Wheelchair
Jun-Uk Chu,In-Hyuk Moon,Gi-Won Choi,Jei-Cheong Ryu,Mu-Seong Mun 한국과학기술원 인간친화 복지 로봇 시스템 연구센터 2004 International Journal of Assistive Robotics and Me Vol.5 No.3
We introduce a design and implementation of brushless DC (BLOC) motor controller for an electric wheelchair. The control architecture consists of two layers of feedback control, namely the wheelchair posture control and the wheel velocity control. In the higher level of control architecture, the posture controller works as a reference velocity generator for the two wheels. We realize the joystick interface and the posture controller in an 8-bit microcontroller. It is on the lower layer that the velocity controller performs four quadrant operations. For the driving system, a DSP-based BLDC motor controller with three-phase inverter module is especially designed using only three Hall-effect sensors and a single dc-link current sensor. The functions of this motor controller include wheel velocity control and torque control. The performance of the control system has been verified experimentally.
Polyamine Stimulation of arcA Expression in Escherichia coli
Rhee, Mun-Su,Kim, Young-Sik,Park, Seon-Young,Park, Myung-Hun,Kim, Bo-Min,Kang, Seong-Uk,Lee, Kui-Joo,Lee, Jong-Ho The Microbiological Society of Korea 2002 The journal of microbiology Vol.40 No.4
The effects of two natural polyamines (putrescine and spermidine) on the synthesis of ArcA, a response regulator of the Arc two-component signal transduction system, were studied using an E. coli mutant deficient in polyamine biosynthesis. Endogenous polyamine deficiency of the mutant resulted in marked reduction in the ArcA level determined by Western blot analysis. Putrescine supplement to the growth medium effectively increased the ArcA level of the mutant in a concentration-dependent manner. Spermidine also stimulated the ArcA level in the mutant to a greater degree than putrescine. Expression of arcA'::lacZ operon fusion in the mutant was stimulated 6-fold and 10-fold by putrescine and spermidine at a 1mM concentration, respectively, indicating that the stimulatory effect of the polyamines on ArcA synthesis is due to transcriptional induction, and that spermidine is a more potent arcA inducer than putrescine. The polyamine-dependent arcA'::lacZ induction was growth-phase-dependent and independent of either arcA or fnr which are two regulators involved in anaerobic stimulation of the Arch level. These results suggested that putrescine and spermidine polyamines may be potential intracellular signal molecules in the control of arcA expression, and thereby may play an important role in cellular metabolism.
Sideband Instability in the Compact THz Free-Electron Laser at KAERI
Young Uk Jeong,Byung Cheol Lee,Grigori M. Kazakevitch,Hyuk Jin Cha,Jungho Mun,Pil Dong Ahn,Seong Hee Park 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.I
A frequency offset of the Sideband instability has been observed in a compact waveguide-mode terahertz (THz) free-electron laser (FEL). The spectra of the FEL pulses were measured by using a Fabry-Perot spectrometer having a resolution of 10$^{-4}$ of the central wavelength at 2 $-$ 3 THz range. The shift of the sideband was measured to be 0.5 $-$ 1.2 $\mu$m, depending on the FEL wavelengths from 110 to 165 $\mu$m. An increase in the sideband shift for a longer wavelength could be explained by a change in the wave's group velocity in a plane-parallel waveguide. Mode competition between the sidebands and the primary wave was observed by changing the cavity length of the FEL. We could decrease the number of modes and reduce the linewidth of the spectra by controlling the cavity detuning. We discuss the dependence of the complexity of the sideband instability on the FEL wavelengths and its gain characteristics.
Jungho Mun,Young Uk Jeong,Byung Cheol Lee,Hyuk Jin Cha,Ji Young Lee,Kitae Lee,Kwon-hae Yea,Pil Dong Ahn,Seong Hee Park,Yong Ho Cha,Yong Woo Lee 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.I
Terahertz (THz) pulses from solid targets, such as an aluminum (Al) and a strong polyester film (Mylar), irradiated by ultra-intense laser pulses were measured by using a liquid-helium-cooled Ge:Ga detector. The irradiating intensity of the Ti:Sapphire laser was more than 10$^{18}$ W/cm$^2$. The typical pulse energy and pulse duration on the target were 200 mJ and 30 fs, respectively. To prevent ultraviolet (UV), visible, and near-infrared (NIR) radiation from being measured by the detector, we used polyethylene (PE) plates and indium-tin-oxide (ITO) films as selective windows and mirrors for the THz radiation. The reflectivity of the ITO film for THz radiation is 10 times higher than that for visible and NIR radiations. The THz wave radiated from a laser-induced plasma has a linear component of the polarization, which may be explained by linear mode conversion from a laser wakefield. This intense and wide-band radiation is expected to be a useful source for various THz applications, as well as for real-time diagnostics for a plasma in which particles are accelerating.
아두이노를 활용한 중력 가속도 측정과 관련된 튜토리얼 및 교육적 활용 방안
김형욱(Hyung-Uk Kim),문성윤(Seong-Yun Mun) 한국콘텐츠학회 2022 한국콘텐츠학회논문지 Vol.22 No.6
MBL을 통한 물리 실험은 학생들이 실험 결과를 바로 확인하고 쉽게 실험을 수행할 수 있어 예전부터 많은 학교에서 활용해 왔다. 하지만, 장치의 원리를 모르고 실험을 수행하거나, 단순히 도출된 데이터에만 집중하는 것이 MBL 실험의 문제점으로 꾸준히 제기되어 왔다. 이러한 문제점을 보완하기 위해, 아두이노를 활용하여 MBL 실험에서 많이 사용되는 피켓펜스의 방법으로 중력 가속도를 측정하고 실제 중력 가속도 값과의 비교를 통해 오차율을 계산했으며, 본 튜토리얼의 교육적 활용에 대한 논의를 해보았다. 실험 결과, 실험으로 구한 중력 가속도 값과 실제 중력 가속도 값의 오차율은 1% 내외로 비교적 정확한 측정이 가능한 것으로 나타났으며, 실험값의 표본평균이 95% 신뢰구간 안에 포함되는 것으로 나타나 유의미한 실험이라는 결론을 내릴 수 있었다. 또한, MBL이 가진 구조적인 단점을 보완할 수 있는 점, 물리와 수학의 상호작용을 고려할 수 있는 점, STEAM 교육에서 정보 교과와의 융합이 가능한 점 그리고 장비 구비비용이 저렴한 점을 통해 측정실험의 교육적 활용 가능성을 보여주었다. 본 자료를 토대로 아두이노를 활용한 물리 실험이 과학영재 교육에서 더욱 활성화될 수 있도록 기대하는 바이다. Physical experiment through MBL has been used in many schools for a long time since students can check the experiment results immediately and conduct the experiment easily. However, conducting the experiment, not knowing the principle of the device or simply concentrating on the derived data has been raised as the problem of MBL experiment. To supplement this problem, this study measured the acceleration of gravity with the picket fence method, which is often used in MBL experiment, utilizing Arduino, calculated the error rate through a comparison to the actual acceleration of gravity and discussed the educational application of the experiment to measure it. As a result of the experiment, the error rate between the acceleration of gravity calculated by the experiment and the actual acceleration of gravity was about 1%, so it turned out that relatively accurate measurements were possible. Also, the sample mean of the experimental value was included in the confidence interval of 95%, so it could be concluded that it was a significant experiment. In addition, this study showed the possibility of the educational application of the experiment to measure it through the following: It can supplement the structural disadvantages of MBL; it can consider the interaction between Physics and Math; it is possible to converge with information course in STEAM education; and it is inexpensive to be equipped with the equipment. Hopefully, the physical experiment utilizing Arduino will further be revitalized in science gifted education based on this study.