• International Journal of Internet, Broadcasting and Communication
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• 제10권4호
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• pp.75-82
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• 2018

Efforts to reduce damages from micro dust and harmful gases in life have been led by national or local governments, and information on air quality has been provided along with real-time weather forecast through TV and internet. It is not enough to provide information on the individual indoor space consumed. So in this paper, we propose a IoT-based Real-Time Air Quality Sensing Board Corresponding Fine Particle for Air Quality Management in Buildings. Proposed board is easy to install and can be placed in the right place. In the proposed board, the air quality (level of pollution level) in the indoor space (inside the building) is easy and it is possible to recognize the changed indoor air pollution situation and provide countermeasures. According to the advantages of proposed system, it is possible to provide useful information by linking information about the overall indoor space where at least one representative point is located. In this paper, we compare the performance of the proposed board with the existing air quality measurement equipment.

• 한국세라믹학회지
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• 제42권5호
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• pp.338-345
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• 2005

To prepare the complex gel of flux and pseudo-boehmite used in precursor of the flaky ${\alpha}-A1_2O_3$ crystal, aqueous solution of the mixture of sodium carbonate and sodium phosphate was added with stirring in aqueous solution of the mixture of sodium sulfate, potassium sulfate and titanium sulfate. The complex gel was dried at $110^{\circ}C$ and was crystallized above $1,050^{\circ}C$, and then the effect of the amount of titanium sulfate on size, morphology, thickness and crystal size distribution of the flaky ${\alpha}-A1_2O_3$ crystal was investigated. Addition of titanium sulfate was prevented the aggregation and generation of twin crystal, and had an effect on the crystal size and the thickness during crystal growth. When the amount of titanium sulfate was more than 6 g, particle size was decreased but was free from crystal twining and aggregation. On the other hand, when the amount of titanium sulfate was lower than 6 g, crystal size was increased but crystal twinning and aggregation were noticed.

• 대한기계학회논문집
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• 제17권7호
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• pp.1649-1657
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• 1993

This paper reports on a proof-of-concept experimental investigation focused on evaluating the vibration characteristics and control of smart hollow cantilever beams filled with an electro-rheological(ER) fluid. The beams are considered to be of uniform viscoelastic materials and modelled as a viscously-damped harmonic oscillator. Electric field-dependent natural frequencies, loss factors and complex moduli are evaluated and compared among three different beams : two types of different volume fraction of ER fluid and one type of different particle concentration of ER fluid by weight. Modal characteristics of the beams are observed in both the absence and the presence of electric potentials. It is also shown that by constructing active control algorithm the removal of structural resonances and the suppression of tip deflection are obtained. This result provides the feasiblility of ER fluids as an active vibration control element.

• Macromolecular Research
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• 제17권7호
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• pp.538-543
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• 2009

In this study, methotrexate (MTX)-encapsulated polymeric micelles using methoxy poly(ethylene glycol) (MPEG)-grafted chitosan (ChitoPEG) copolymer were prepared. The MIX-incorporated polymeric micelles of ChitoPEG copolymer has a particle size of around 50-100 nm. In 1H nuclear magnetic resonance (NMR) study, the specific peaks of MTX disappeared in heavy water ($D_2O$) and only the specific peak of MPEG was observed, while all of the peaks were confirmed in dimethyl sulfoxide (DMSO). These results indicated that MTX was complexed with chitosan and then formed an ion complex inner-core of the polymeric micelle in an aqueous environment. The drug contents of the polymeric micelle were around $4{\sim}12%$ and the loading efficiency of MTX in the polymeric micelles was higher than 60% (w/w) for all of the formulations. The cytotoxicity of MIX and MTX-incorporated polymeric micelle against CT26 tumor cells was not significantly changed.

• 제어로봇시스템학회논문지
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• 제12권8호
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• pp.746-751
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• 2006

In this paper, we present tracking algorithm for the indoor moving object. We research passive method using a camera and image processing. It had been researched to use dynamic based estimators, such as Kalman Filter, Extended Kalman Filter and Particle Filter for tracking moving object. These algorithm have a good performance on real-time tracking, but they have a limit. If the shape of object is changed or object is located on complex background, they will fail to track them. This problem will need the complicated image processing algorithm. Finally, a large algorithm is made from integration of dynamic based estimator and image processing algorithm. For eliminating this inefficiency problem, image based estimator, Mean-shift Algorithm is suggested. This algorithm is implemented by color histogram. In other words, it decide coordinate of object's center from using probability density of histogram in image. Although shape is changed, this is not disturbed by complex background and can track object. This paper shows the results in real camera system, and decides 3D coordinate using the data from mean-shift algorithm and relationship of real frame and camera frame.

• 한국환경과학회지
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• 제22권7호
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• pp.837-845
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• 2013

This study was designed to synthesize mesoporous carbon, porous carbonic material and to characterize its surface in an attempt to adsorption methane gas($CH_4$). Synthesis of mesoporous carbon was carried out under two steps ; 1. forming a RF-silica complex with a mold using CTMABr, a surfactant, and TEOS, raw material of silica, and 2. eliminating silica through carbonization and HF treatment. The mesoporous carbon was synthesized under various conditions of synthesis time and calcination. Eight different types of mesoporous carbon, which were designated as MC1, MC2, MC3, MC4, MCT1, MCT2, MCT3, and MCT4, were prepared depending upon preparation conditions. The analysis of mesoporous carbon characteristics showed that the calcination of silica stabilized the mixed structure of silica and carbonic complex, and made the particle uniform. The results also showed that hydrothermal synthesis time did not have a strong influence on the size of pore. The bigger specific surface area was obtained as the hydrothermal synthesis time was extended. However, the specific surface area was getting smaller again after a certain period of time. In adsorption experiments, $CH_4$ was used as adsorbate. For the case of $CH_4$, MCT3 showed the highest adsorption efficiency.

• 한국산학기술학회논문지
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• 제13권11호
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• pp.5601-5609
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• 2012

본 논문은 포항철강공단 및 주변지역의 보건 및 환경영향 인자를 확인하기 위하여 미세먼지($PM_{10}$) 농도와 성분을 측정 및 분석하였다. 또한 지역대기자동측정망 자료를 이용하여 연별, 계절별 $PM_{10}$ 농도분포를 조사하였다. 공단지역 내 $PM_{10}$을 측정한 결과, 동일산업에서 측정된 $PM_{10}$ 평균농도는 $61.3{\pm}12.1{\mu}g/m^3$, 철강공단관리사무소에서 측정된 $PM_{10}$ 평균농도는 $44.3{\pm}8.1{\mu}g/m^3$으로 나타나 대기환경기준을 만족하였다. 공단지역 동일산업과 철강공단관리사무소에서 측정된 $PM_{10}$ 중 이차생성 이온인 ${SO_4}^{2-}$, $NO_3{^-}$, $NH_4{^+}$의 분율을 확인한 결과, ${SO_4}^{2-}$의 분율이 높게 나타났고, 황산염과 관련된 오염원이 철강공단지역에 존재하는 것으로 판단된다. 전체적으로 동일산업 지점에서는 ${SO_4}^{2-}$ > $Cl^-$ > $NO_3{^-}$ > $F^-$ > $NH_4{^+}$ 순으로 나타났고, 철강공단관리사무소 지점에서는 ${SO_4}^{2-}$ > $Cl^-$ > $NO_3{^-}$ > $NH_4{^+}$ > $F^-$ 순으로 나타났다.

• 한국세라믹학회지
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• 제39권1호
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• pp.33-37
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• 2002

착체중합법을 이용하여 $SrA1_2O_4:Eu^{2+}$ 인광체 분말을 합성하고 분말특성과 발광특성을 고상반응법으로 제조한 것과 비교하였다. 착체중합법에서는 $SrA1_2O_4:Eu^{2+}$분말이 $900^{\circ}C$에서, 고상반응법에서는 $1200^{\circ}C$에서 합성되었다. 착체중합법으로 합성한 분말은 합성온도가 낮은 만큼 크기가 약 $0.1{\mu}m$로 고상반응에 의한 것의 1/10정도였으나, 탄소가 잔류하여 모상격자의 결정도가 낮아지고 순백색이 되지 못하였다. 두 분말 모두 상온에서 520nm 부근에서 최대 발광 피크를 나타냈으나, 착체중합법으로 합성한 분말이 약간 낮은 파장대에서 최대 피크를 보였으며 피크의 반가폭은 약간 크고 강도는 크게 감소하였다. 이러한 발광 특성의 변화는 주로 입경의 차이에 의한 것이나 잔류탄소도 영향을 미친 것으로 사료되었다.

• 한국결정성장학회지
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• 제12권5호
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• pp.229-233
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• 2002

유기화학적 방법인 착체중합법을 이용하여 나노사이즈의 ZnO 분말을 저온에서 합성하였다. 고분자 전구체는 Zn nitrate hexahydrate를 사용하였고, chelating agent로서 citric acid를 reaction medium으로서 ethylene glycol을 혼합하여 제조하였다. 고분자 전구체를 300~$700^{\circ}C$의 온도범위에서 3시간 동안 하소하였으며, 열분해와 결정화 과정을 TG-DTA, FI-IR과 XRD 등을 이용하여 분석하였다. 결정화 온도에 따른 입자의 형상이나 크기를 SEM, TEM의 분석 및 Scherrer's equation을 이용한 계산을 통하여 관찰 및 비교를 하였다. ZnO의 결정화는 $300^{\circ}C$부터 시작되었고, $400^{\circ}C$에서 완전히 합성되었음을 알 수 있었다. 400~$700^{\circ}C$에서 하소된 ZnO 입자들은 대부분 둥근 형태로 균일하게 분포되었으며, $400^{\circ}C$에서 하소된 분말의 평균입도는 약 30~40nm를 보였다. 일반적으로 온도의 상승에 따라 입경이 증가되는 일반적인 경향이 관찰되었다.

• 한국재료학회지
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• 제8권7호
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• pp.616-620
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• 1998

착체증합법 및 연소합성법에 의해 Zn_{0.994}Mn_{0.006}Ga_2O_4$녹색형광체 분말을 합성하였으며, 이들의 분말 및 발광특성을 XRD, SEM, BET, PL 등을 사용하여 조사하였고, 이를 고상반응법에 의하여 합성한 시료와 비교하였다. 착체중합법과 연소합성법에 의해 합성한 시료는 각각 $500^{\circ}C$와 $400^{\circ}C$에서 단일 스피텔 상이 생성되었으며, 이들의 입자크기는 고상반응에 의해 합성된 분말에 비하여 작았다. 한편, 착체중합법에 의하여 합성한 분말의 발광강도는 열처리 온도가 $900^{\circ}C$일 때, 연소합성법에서는 반응온도가 $400^{\circ}C$일 때 각각 최대값을 나타내었다.