Fabrication and evaluation of SU-8 based wireless pressure sensor

Gang-Hyeon Sun(선강현),Dong-Su Kim(김동수),Dong-weon Lee(이동원) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.6

In the recent years, the development of wireless sensors has attracted attention, with the development of MEMS(Micro-Electro-Mechanical-System) technology. The pressure sensor, one of the wireless sensor, is a device that measures the applied force, pressure, by a liquid or gas on a surface and translates it to the electrical signal. We fabricate this sensor based on capacitive type which measures change in capacitance with two metal plates. One of the two capacitor plates acts as the diaphragm that is displaced by the pressure, changing the capacitance of the circuit. Variation of signal detected by network analyzer evaluates the resonance frequency and phase shift with different interrogate distance and pressure force. [그림 본문 참조]

우리나라 논 관개용 지하수 수질 특성

김진호,조광래,임수정,이경자,경기천,엄미정,김희권,김찬용,이영한,이신찬,윤순강 한국환경농학회 2003 한국환경농학회지 Vol.22 No.4

This study was carried out to evaluate the status of the groundwater quality for paddy fields irrigation in Korea. Water samples were collected at 130 sites throughout the country. Samples were collected at three seasons-April, July and October-in 2000. According to our survey, the groundwater was found to be suitable for irrigation purpose. Average EC was shown 0.286 dS/m. Nitrate-nitrogen and Cl^(-) concentration was 5.6 ㎎/L, 32.95 ㎎/L which satisfied the Korean Standards for Irrigation Water. Nitrate-nitrogen concentration in each province was shown as following orders: Jeju (11.17 ㎎/L) > Chungnam (8.16 ㎎/L) > Gyeongbuk (6.64 ㎎/L) > Gyounggi (5.91 ㎎/L) > Chungnam (4.95 ㎎/L) > Gyeongnam (3.91 mgk) > Jeonbuk (3.50 ㎎/L) > Jeonnam (3.27 ㎎/L) > Gangwon (2.91 ㎎/L). The concentration by sampling seasons were October (6.62 ㎎/L) > July (5.88 mg&) > April (4.78㎎/L). As the soil of Jeju Province is usually derived from volcanic ash soils mainly used for upland drops, it may influence the nitrate-nitrogen concentration of groundwater. The amount of rainfall also influence the water quality. But the COD_(Cr), were shown April (3.17㎎/L) > July (2.91 ㎎/L) > October (2.40 ㎎/L), it is highly related in the basal dose of organic matter fertilizers. This study demonstrated that groundwater quality was suitable for irrigation, but continuous monitoring is recommended for agricultural policy and developing OECD agricultural environment indicators.

뇨중 Acebutolol과 Acetyl대사체의 HPLC 분석

강영구,김영수,백채선 朝鮮大學校 1996 藥學硏究誌 Vol.18 No.1

A simple, sensitive high-performance liquid chromatographic assay for the simultaneous determination of acebutolol and acebutolol acetyl metabolite in human urine is described. These compounds are separated by a reversed -phase chromatographic system (MicroPak MCH-10 ODS column) with acetonitrile-0.IM phosphate buffer-water(55:6:39,v/v) as mobile phase at a flow rate of 1.0ml/min and fluorescence detection at 335nm(Ex.) and 475 nm(Em.) The retention times of acebutolol acetyl metabolite, acebutolol and internal standard were 6.42, 9.52 and 12.01min respectively in the urine. The pH of mobile phase was adjusted to 5.0 with phosphoric acid. Protein sample was precipitated by the addition of methanol. The internal standard used was meclofenamate. The sensitivity of the method is 0.15 ㎍/㎖. Quantification was achieved by the measurement of the peak height ratio, and the relative recovery rate ranged from 94 to 99% when compared with that from water. Inter-day coefficients of variation(CV) ranged 0.42 - 2.11% for acebutolol and 0.74 - 3.13% for acetyl metabolite, and intra-day CV varied 0.31 - 2.11 % for acebutolol and 1.57 - 6.40 % for acetyl metabolite. The method may be used for Pharmacokinetic studies, therapeutic control, and the optimization of treatment.

Study on an Optimal Control Method for Energy Injection Resonant AC/AC High Frequency Converters

Su, Yu-Gang,Dai, Xin,Wang, Zhi-Hui,Tang, Chun-Sen,Sun, Yue The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.2

In energy injection resonant AC-AC converters, due to the low frequency effect of the AC input envelope and the low energy injection losses requirement, the constant and steady control of the high frequency AC output envelope is still a problem that has not been solved very well. With the aid of system modeling, this paper analyzes the mechanism of the envelope pit on the resonant AC current. The computing methods for the critical damping point, the falling time and the bottom value of the envelope pit are presented as well. Furthermore, this paper concludes the stability precondition of the system AC output. Accordingly, an optimal control method for the AC output envelope is put forward based on the envelope prediction model. This control method can predict system responses dynamically under different series of control decisions. In addition, this control method can select best series of control decisions to make the AC output envelope stable and constant. Simulation and experimental results for a contactless power transfer system verify the control method.

Study on an Optimal Control Method for Energy Injection Resonant AC/AC High Frequency Converters

Yu-Gang Su,Xin Dai,Zhi-Hui Wang,Chun-Sen Tang,Yue Sun 전력전자학회 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.2

In energy injection resonant AC-AC converters, due to the low frequency effect of the AC input envelope and the low energy injection losses requirement, the constant and steady control of the high frequency AC output envelope is still a problem that has not been solved very well. With the aid of system modeling, this paper analyzes the mechanism of the envelope pit on the resonant AC current. The computing methods for the critical damping point, the falling time and the bottom value of the envelope pit are presented as well. Furthermore, this paper concludes the stability precondition of the system AC output. Accordingly, an optimal control method for the AC output envelope is put forward based on the envelope prediction model. This control method can predict system responses dynamically under different series of control decisions. In addition, this control method can select best series of control decisions to make the AC output envelope stable and constant. Simulation and experimental results for a contactless power transfer system verify the control method.

New stereotactic adaptor system for cynomolgus monkey (Macaca fascicularis)

Hyung-Sun Kim,Dong-ho Woo,Young-Su Yang,Goo-Hwa Gang,Hyoung-Ihl Kim,Su-Chul Han 한국실험동물학회 2017 한국실험동물학회 학술발표대회 논문집 Vol.2017 No.2

소아 촬영 시 선량감소 및 화질 향상을 위해 고안된 차폐가운 사용에 따른 유용성 평가

이선미(Sun-Mi Lee),심지나(Ji-na Shim),정지상(Ji-sang Jung),이용수(Yong-Su Lee),진덕은,강성호(Sung-Ho Gang),임재식(Jea-Sik Lim) 대한영상의학기술학회 2014 대한영상의학기술학회 논문지 Vol.2014 No.1

목 적 : 본 연구는 성인에 비해 방사선감수성이 높은 소아의 일반 x선 촬영 시 환자가 받는 유효선량을 감소시키고 화질 향상에 도움을 줄 수 있는 자체제작 차폐가운의 유용성에 대해 검토하고자 하였다. 대상 및 방법 : 실험에 사용된 장비는 GE사의 Definium 8000과 직경 15cm, 높이 20cm의 CTDI 원통형 아크릴팬텀, 자체 제작한 차폐가운을 사용하였다. 차폐가운은 Pb 0.25mm apron 소재를 사용하여 가로 45cm, 세로 55cm, 폭 15cm의 ‘ㅁ’형태로 제 작하였다. 밸크로를 이용하여 ROI 크기를 변경할 수 있도록 고안되었다. 실험은 대조군(차폐가운 비사용 시)과 실험군(차폐가운을 사용 시)으로 나누어 장비에 표시된 mAs, DAP값을 기록하였고, 각 촬영은 10회씩 시행하여 평균값을 구하였고 ‘SPSS’ program을 통 해 Wilcoxon 부호순위 검정을 시행하여 유의성을 검증하였다. <실험1> Manual mode(65kVp, 8mAs)로 장비의 collimator를 이용하여 40cm*40cm, 35cm*35cm, 30cm*30cm, 25cm*25cm, 20cm*20cm으로 ROI 크기를 변화하여 촬영하였다. <실험2> AEC(Auto exposure control) mode(관전압 65kVp)에서 <실험1>과 동일한 방법으로 촬영하였다. <실험3> 65kVp, 8mAs의 조사조건으로 collimation은 최대로 설정하고 차폐 가운을 이용하여 <실 험1>과 동일하게 ROI 크기를 변화하여 촬영하였다. <실험4> AEC mode(관전압 65kVp)에서 <실험3>와 동일한 방법으로 촬영하였다.  ‘PCXMC2.0’ program을 통해 DAP값을 이용하여 유효선량을 계산하였고, ‘ImageJ’ program을 이 용하여 영상의 SNR을 구하여 화질평가를 시행하였다. 결 과 : AEC mode에서 실험군이 대조군에 비해 mAs가 평균 5%낮게 조사되었다. 유효선량도 AEC mode에서 실험군이 대조군에 평균 9.7% 낮았다. 하지만 SNR은 Manual mode 와 AEC mode에서 모두 평균 7% 향상 되었다. p value가 0.05미만 일 때 실험군과 대조군의 차이가 유의함이 증명되었다. 결 론 : 자체 제작한 차폐 가운의 사용으로 기존의 AEC mode에서 소아 촬영 시 발생했던 문제점을 보완하여 ROI영역 내 유효선량을 감소시키고 ROI영역 밖의 후방산란을 제거하여 화질향상에 도움을 줄 수 있었다. 또한 ROI영역 밖의 부위를 차폐하여 불필요한 피폭을 방지하고 소아를 고정시키는 검사자와 검사보조자의 손을 X선으로부터 보호할 수 있게 되었다. Purpose : This study examine the usefulness of newly digined protector for pediatric patients who highly sensitive to radiation than adults to reduce the effective dose and improve the quality of image. Materials and Methods : The experiments was performed with GE Definium 8000, cylindrical CTDI acrylic   phantom(diameter 15cm, height 20cm) and newly designed protector. Protector made by  Pb 0.25mm , width 45cm, height 55cm, It was constructed by ㅁ form. Using Velcro been designed to change the size of the ROI. Divided the control experiment (non-use protector) and experimental (protector was used). The valuse of mAs, DAP shown the equipment were recorded for each exmaination. Through SPSS program  the Wilcoxon signed rank test was performed to verify the significance. <Experiment 1> With Manual mode (65kVp, 8mAs), using the collimator of equipment the size of the ROI varied 40cm * 40cm, 35cm * 35cm, 30cm * 30cm, 25cm * 25cm, 20cm * 20cm. <Experiment 2> With AEC (Auto exposure control) mode (65kVp), take same method  as <experiment 1>. <Experiment 3> With Manual mode (65kVp, 8mAs), using the protector the size of the ROI varied. <Experiment 4> With AEC (Auto exposure control) mode (65kVp), take same method  as <experiment 3>.  PCXMC2.0 program through the DAP values were calculated by using the effective dose, ImageJ program to obtain the SNR of the image quality assessment was performed. Result : The values of mAs were lower 5% in the experimental group compared with the control group with AEC mode. Also, The values of effective dose were lower 9.7% in the experimental group compared with the control group with AEC mode. But, The values of SNR were improved 7% with AEC mode and Manual mode. When the p value was less than 0.05 the difference between the experimental group and the control group was demonstrated significance. Conclusion : By using of newly digned protector for pediatic, some problems are supplied in AEC mode, effective dosed in ROI area was reduced. And image quality was improved by removing the backscattering X ray, outside of ROI area was protected from X-ray

Effect of Postharvest Several Treatments Including MAP of Leafy and Fruit Vegetables During Vessel Export to Singapore

Min-Sun Chang,Yoonpyo Hong,Ji Gang Kim,Mehea Park,Hyun Jin Choi,Jin-Su Lee,Jung-Soo Lee 한국원예학회 2018 한국원예학회 학술발표요지 Vol.2018 No.10

Theoretical Studies on Mechanism and Kinetics of the Hydrogen-Abstraction Reaction of CF_3CH_2CHO with OH Radicals

Cheng-gang Ci,Hong-bo Yu,Su-qin Wan,Jing-yao Liu,Chia-Chung Sun 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.4

The hydrogen abstraction reaction of CF_3CH_2CHO + OH has been studied theoretically by dual-level direct dynamics method. Two stable conformers, trans- and cis-CF_3CH_2CHO, have been located, and there are four distinct OH hydrogen-abstraction channels from t-CF_3CH_2CHO and two channels from c-CF_3CH_2CHO. The required potential energy surface information for the kinetic calculation was obtained at the MCG3-MPWB//M06-2X/aug-cc-pVDZ level. The rate constants, which were calculated using improved canonical transitionstate theory with small-curvature tunneling correction (ICVT/SCT) were fitted by a four-parameter Arrhenius equation. It is shown that the reaction proceeds predominantly via the H-abstraction from the -CHO group over the temperature range 200-2000 K. The calculated rate constants were in good agreement with the experimental data between 263 and 358 K.

ERRATUM Bull. Korean Chem. Soc. 2011, Vol. 32, No. 4, pp 1187~1194

Cheng-gang Ci,Hong-bo Yu,Su-qin Wan,Jing-yao Liu,Chia-Chung Sun 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.7