• 전력전자학회논문지
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• 제10권2호
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• pp.138-147
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• 2005

최근 급속도로 발전된 산업분야에서 요구되는 서보 시스템에서의 빠른 응답특성과 고도의 정밀성을 구현하기 위하여 고속의 연산을 수행할 수 있는 DSP(Digital Signal Processor)의 사용이 필수적이다. 그러나 기존의 DSP는 고속의 연산을 주력으로 전동기 제어에 필요한 PWM 게이팅 발생 장치와 엔코더 입력 장치, ADC(Analog to Digital Converter)등의 주변 장치를 포함하지 않았다. 이러한 추가적인 주변회로로 인한 제어 회로의 복잡성과 보드의 대형화 및 생산단가 상승의 요인으로 작용하였다. 따라서 본 논문에서는 연산 능력이 기존의 DSP에 뒤지지 않으며 전동기 제어 주변회로를 포함하고 있는 TMS320F2812 DSP를 사용하여 현재 산업 현장에서 사용되고 있는 SPMSM 서보 시스템을 제어하여 기존 제어기의 주변회로로 인한 문제점을 해결하고자 한다.

• 한국전기전자재료학회논문지
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• 제33권3호
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• pp.181-185
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• 2020

Hazardous and noxious substance (HNS) detection sensors were fabricated using multi-walled carbon nanotubes (MWCNTs) and various binder materials for ion batteries. To obtain uniformly printed films, the printing precision according to the substrate cleaning method was monitored, and the printing paste mixing ratio was investigated. Binders were prepared using styrene butadiene rubber + carboxymethyl cellulose (SBR+CMC), polyvinylidene fluoride + n-methyl-2-pyrrolidene (PVDF+NMP), and mixed with MWCNTs. The surface morphology of the printed films was examined using an optical microscope and a scanning electron microscope, and their electrical properties are investigated using an I-V sourcemeter. Finally, sensing properties of MWCNT printed films were measured according to changes in the concentration of the chemical under the various applied voltages. In conclusion, the MWCNT printed films made of (SBR+CMC) were found to be feasible for application to the detection of hazardous and noxious chemicals spilled in seawater.

• 센서학회지
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• 제25권1호
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• pp.51-56
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• 2016

This study evaluates the performance of an optical sensor and measurement system (CMA-24) which can analyze the fluctuation of dissolved oxygen and pH simultaneously. In the optical sensor system, the fluorescent materials, Rudpp and HPTS which are sensitive to dissolved oxygen and pH, respectively, are coated on the bottom of a 24-well -plate by the sol-gel technology. The detection times of the emission light of the oxygen sensor were $4,186{\pm}13.90{\mu}s$ and $4,452{\pm}36.68{\mu}s$ for the dissolved oxygen of 17% $O_2$ and 7.6% $O_2$, respectively. On the other hand, the detection times of the pH sensor were $6,699.43{\pm}14.64{\mu}s$, $6,722.24{\pm}6.21{\mu}s$, and $6,748.52{\pm}2.63{\mu}s$ using pH 6, 7, and 8, respectively. When we determined cellular respiration levels of C2C12 myocytes with CMA-24, $O_2$/pH measurement system, the ratio of the uncoupled to coupled OCR (oxygen consumption rate) was 1.41. The results mean that this CMA-24 system shows almost the same sensitiveness as the commercial system.

• 센서학회지
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• 제5권5호
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• pp.47-54
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• 1996

$WO_{3}$모물질에 Pt와 $SnO_{2}$ 활성촉매를 첨가하여 수 ppm정도의 NOx를 감지할 수 있는 후막형 NOx센서를 제조하였다. 센서의 최대 감도는 $250^{\circ}C$정도에서 얻을 수 있었으나, 회복속도를 고려하여 $330^{\circ}C$에서 특성실험을 실시하였다. 기존의 $WO_{3}$를 사용한 것보다 감도, 반응 및 회복 속도가 개선되었고 또한 뛰어난 선택성과 기체흐름에 대한 안정성을 보여주었다. 농도변화에 대한 선형성이 우수하게 나타남으로 계측기에 응용가능성을 보여주었다.

• 센서학회지
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• 제5권5호
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• pp.63-68
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• 1996

출력신호를 검출하기 위한 집적화한 용량형 압력센서를 구현하기 위해서는 센서의 특성에 나쁜 영향을 미치는 기생용량, 온도/열 드리프트 및 누설전류 등의 요소가 개선 되어야 한다. 본 논문에서는 2개의 용량-주파수 변환기와 4비트 디지탈 보상회로로 구성된 새로운 이상적인 인터페이스 회로를 설계 하였다. 이 회로는 센싱 센서 주파수를 기준 센서 주파수로 나누어줌으로써 드리프트 및 누설전류의 영향이 제거될 수 있도록 설계 되었고, 신호 전송시 잡음의 영향이 적은 디지탈 신호를 처리하도록 되어있다. 그르므로 이 회로는 디지탈 비트수를 늘려 줌으로 출력신호의 분해능을 향상 시킬 수 있다. 또 이 회로 중 디지털 부분은 FPGA 칩으로 제작되어 그 작동이 확인 되었다.

• 한국위성정보통신학회논문지
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• 제9권2호
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• pp.1-6
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• 2014

전 세계적으로 인공위성의 수요가 증가됨에 따라 위성영상을 활용한 다양한 분야에서 연구가 진행되고 있다. 본 논문에서는 지구관측 인공위성을 활용한 농림업 분야의 위성영상 활용현황 분석과 농림업 분야에서 활발히 사용 중인 위성의 종류 및 시스템 사항을 분석한다. 위성영상을 활용한 국내 농림업 연구현황을 분석하기 위해 최근 5년간의 국내 논문을 수집하여 통계분석을 진행하고, 이를 통해 농림업 분야에서의 위성영상 활용현황을 분석하고 최근 세계적으로 운용되는 중형급 위성 영상을 활용하여 농림업 분야에 적용될 수 있는 기술을 조사한다. 이러한 분석 자료는 향후 중형급 위성이 구현될 때 위성영상을 활용하는 수요자에게 적합한 사양을 제공할 수 있는 방향으로 사업 계획을 수립할 수 있는 정책적인 참고 자료가 될 것으로 기대된다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.366-366
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• 2002

Cloud-to ground lightning and total precipitation over Korean peninsula during the summer monsoon season are studied extensively with a special emphasis on the characteristics of convective precipitation. Ten years (1988-1997) lightning and rainfall data and a temporal and spatial scale of one month and 10$^2$ km$^2$ respectively are used to calculate the monthly number of CG lightning flash count. Monsoonal convective activity is higher over the west coast with maxima at two different regions, one in the northern part which increases nortwestward and the other is at the middle west coast of Korea increasing towards the west coast. East coast represents the minimum value of monsoonal convective activity. In the east coast of Korean peninsula, particularly in the region east of Tae-back mountain, the value of Rain yield, (which is defined as the ratio of total precipitation to CG flash count over a common area), is maximum with an average value of 3$\times$10$^{8}$ kg fl$^{-1}$, while the minimum value of rain yield is occurred in the west of Tae-back mountain, with an average value of 0.8$\times$10$^{8}$ kg fl$^{-1}$. Results show in the west coast stations, nearly 82% of the total rainfall is convective in nature, at the middle of the peninsula 53% of the total rain is convective while in the east coast stations 46% contribution from the convective rain is seen. Kanghwa receives the maximum convective rain while at Ulsan the convective rain is minimum. Correlation coefficient between the total precipitation and CG lightning during the summer monsoon season is 0.54.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.970-972
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• 2003

Due to rapid increase in the demand of Natural Rubber (NR) few years ago, NR price sore very higher. The rubber plantation in Thailand expanded very fast to non traditional areas with the result Thai become the biggest NR exporting country in the world. However, the average yield is still lower compared to experimental yield of RRIT (Rubber Research Institute of Thailand) or just 60 % (RRIT, 1998). This is due to many of new rubber planting areas, which are not suitable. The Thai Ministry of Agriculture and Cooperatives thus has set 'The complete cycle development strategies for natural rubber' in the medium-term measures by reducing the rubber planting areas by 300,000 rai (1 rai = 0.16ha) through replanting with oil palm. The aim of this study is to find out land having lowest potential for rubber production (R3) but highest for oil palm production (P1). Find areas which are unsuitable for rubber and can be replaced by oil palm in order to get a better agricultural production. The study was applied upon Krabi province, Thailand. Crops requirement, degree of limitation to crops growth, climatic data, crops yield, soil map, topographic map etc., were used to evaluate land potential for both rubber and oil palm production according to FAO framework (Sys, 1992). An Agro-ecological suitability map for rubber and oil palm were produced. This was done by mean of GIS. The database was generated and guide map for the decision makers in view of suitable crop substitution was prepared.

• 한국재료학회지
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• 제27권12호
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• pp.658-663
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• 2017

Urchin-structured zinc oxide(ZnO) nanorod(NR) gas sensors were successfully demonstrated on a polyimide(PI) substrate, using single wall carbon nanotubes(SWCNTs) as the electrode. The ZnO NRs were grown with ZnO shells arranged at regular intervals to form a network structure with maximized surface area. The high surface area and numerous junctions of the NR network structure was the key to excellent gas sensing performance. Moreover, the SWCNTs formed a junction barrier with the ZnO which further improved sensor characteristics. The fabricated urchin-structured ZnO NR gas sensors exhibited superior performance upon $NO_2$ exposure with a stable response of 110, fast rise and decay times of 38 and 24 sec, respectively. Comparative analyses revealed that the high performance of the sensors was due to a combination of high surface area, numerous active junction points, and the use of the SWCNTs electrode. Furthermore, the urchin-structured ZnO NR gas sensors showed sustainable mechanical stability. Although degradation of the devices progressed during repeated flexibility tests, the sensors were still operational even after 10000 cycles of a bending test with a radius of curvature of 5 mm.

• Nuclear Engineering and Technology
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• 제39권3호
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• pp.193-206
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• 2007

The Korea Atomic Energy Research Institute has developed an advanced fast reactor concept, KALIMER-600, which satisfies the Generation IV reactor design goals of sustainability, economics, safety, and proliferation resistance. The concept enables an efficient utilization of uranium resources and a reduction of the radioactive waste. The core design has been developed with a strong emphasis on proliferation resistance by adopting a single enrichment fuel without blanket assemblies. In addition, a passive residual heat removal system, shortened intermediate heat-transport system piping and seismic isolation have been realized in the reactor system design as enhancements to its safety and economics. The inherent safety characteristics of the KALIMER-600 design have been confirmed by a safety analysis of its bounding events. Research on important thermal-hydraulic phenomena and sensing technologies were performed to support the design study. The integrity of the reactor head against creep fatigue was confirmed using a CFD method, and a model for density-wave instability in a helical-coiled steam generator was developed. Gas entrainment on an agitating pool surface was investigated and an experimental correlation on a critical entrainment condition was obtained. An experimental study on sodium-water reactions was also performed to validate the developed SELPSTA code, which predicts the data accurately. An acoustic leak detection method utilizing a neural network and signal processing units were developed and applied successfully for the detection of a signal up to a noise level of -20 dB. Waveguide sensor visualization technology is being developed to inspect the reactor internals and fuel subassemblies. These research and developmental efforts contribute significantly to enhance the safety, economics, and efficiency of the KALIMER-600 design concept.