• Title/Summary/Keyword: Nano Fluid

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Microwave-assisted Photocatalytic Degradation of Methylene Blue (마이크로웨이브가 부가된 광촉매에 의한 메틸렌블루의 분해)

  • Kim, Yu-Bong;Jo, A-Ra;Ra, Deog-Gwan;Park, Jae-Hyeon;Kim, Sun-Jae;Jung, Sang-Chul
    • Journal of Korean Society of Environmental Engineers
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    • v.30 no.8
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    • pp.817-822
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    • 2008
  • In this study, the photocatalytic degradation of methylene blue in TiO$_2$ particles-dispersed water solution was carried out by irradiating microwave and UV light simultaneously. A microwave-discharged electrodeless UV lamp was developed to use microwave and UV simultaneously for photocatalytic reactions. The results of photocatalytic degradation of methylene blue showed that the decomposition rate increased with the microwave intensity, the circulating fluid velocity, and the amount of TiO$_2$ particles and auxiliary oxidizing agents added. Especially, the rate constant of H$_2$O$_2$-added photocatalytic reaction increased about three times from 0.0075 min$^{-1}$ to 0.0250 min$^{-1}$ when microwave was additionally irradiated. This study demonstrates that the microwave irradiation can play a very important role in photocatalytic degradation using peroxides although it is not easy to quantitatively assess the effect of microwave on photocatalytic reactions from the experimental data of this study.

Biological activity of supercritical extraction residue 60% ethanolic extracts from Ulmus davidiana (느릅나무 초임계 추출박 60% 주정추출물의 생리활성)

  • Mun, Myung-Jae;Park, Kwang-Hyun;Choi, Sun Eun
    • Journal of Convergence for Information Technology
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    • v.8 no.5
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    • pp.29-36
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    • 2018
  • Ulmus davidiana supercritical fluid residue EtOH extracts(USCFR) and ethyl acetate solvent fraction (USCFREA) of supercritical extraction foil were investigated in order to examine the recycling of supercritical extraction foil in the process of studying Ulmus davidiana branch supercritical extract. Experiments were performed for the determination of total phenol content. The $IC_{50}$ value(ppm) of DPPH radical scavenging activity and ABTS radical scavenging activity was $7.42{\pm}0.09$, $7.50{\pm}0.05$, $22.94{\pm}0.09$, $6.43{\pm}0.10$, and USCFREA, respectively, as compared with the positive control (vitamin C) with values $17.80{\pm}0.14$ and $5.34{\pm}0.06$, respectively. The antioxidative activities of USCFR and USCFREA were confirmed to be superior to the positive control group. In anti-allergic activity studies, both USCFR and USCFREA showed concentration-dependentanti-allergic activity, and USCFREA showed strong anti-allergic activity even at very low concentrations. Thetotal phenolic contents (ugEG, ugGA; ppm) of USCFR were $134.17{\pm}0.13$, $132.02{\pm}0.24$ and USCFREA were $154.77{\pm}1.05$ and $153.18{\pm}1.10$, respectively. Based on the above results and strong antioxidant activity, USCFR and USCFREA hold the potential to be considered as basic research materials for the development of therapeutic supplements based medicines or functional cosmetics related to chronic inflammatory skin immunity diseases.

Emotion-on-a-chip(EOC) : Evolution of biochip technology to measure human emotion (감성 진단칩(Emotion-on-a-chip, EOC) : 인간 감성측정을 위한 바이오칩기술의 진화)

  • Jung, Hyo-Il;Kihl, Tae-Suk;Hwang, Yoo-Sun
    • Science of Emotion and Sensibility
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    • v.14 no.1
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    • pp.157-164
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    • 2011
  • Emotion science is one of the rapidly expanding engineering/scientific disciplines which has a major impact on human society. Such growing interests in emotion science and engineering owe the recent trend that various academic fields are being merged. In this paper we propose the potential importance of the biochip technology in which the human emotion can be precisely measured in real time using body fluids such as blood, saliva and sweat. We firstly and newly name such a biochip an Emotion-On-a-Chip (EOC). EOC consists of biological markers to measure the emotion, electrode to acquire the signal, transducer to transfer the signal and display to show the result. In particular, microfabrication techniques made it possible to construct nano/micron scale sensing parts/chips to accommodate the biological molecules to capture the emotional bio-markers and gave us a new opportunities to investigate the emotion precisely. Future developments in the EOC techniques will be able to help combine the social sciences and natural sciences, and consequently expand the scope of studies.

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The Electrochemical Studies of Non-enzymatic Glucose Sensor on the Nickel Nanoparticle-deposited ITO Electrode (ITO 전극 위에 고정된 니켈 나노 입자를 이용한 무효소 혈당센서에 관한 전기화학적인 연구)

  • Oh, In-Don;Kim, Samantha;Choi, Young-Bong
    • Journal of the Korean Electrochemical Society
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    • v.17 no.3
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    • pp.164-171
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    • 2014
  • A highly sensitive and selective non-enzymatic glucose sensor has gained great attention because of simple signal transformation, low-cost, easily handling, and confirming the blood glucose as the representative technology. Until now, glucose sensor has been developed by the immobilization of glucose oxidase (GOx) on the surface of electrodes. However although GOx is quite stable compared with other enzymes, the enzyme-based biosensors are still impacted by various environment factors such as temperature, pH value, humidity, and toxic chemicals. Non-enzymatic sensor for direct detecting glucose is an attractive alternative device to overcome the above drawbacks of enzymatic sensor. Many efforts have been tried for the development of non-enzymatic sensors using various transition metals (Pt, Au, Cu, Ni, etc.), metal alloys (Pt-Pb, Pt-Au, Ni-Pd, etc.), metal oxides, carbon nanotubes and graphene. In this paper, we show that Ni-based nano-particles (NiNPs) exhibit remarkably catalyzing capability for glucose originating from the redox couple of $Ni(OH)_2/NiOOH$ on the surface of ITO electrode in alkaline medium. But, these non-enzymatic sensors are nonselective toward oxidizable species such as ascorbic acid the physiological fluid. So, the anionic polymer was coated on NiNPs electrode preventing the interferences. The oxidation of glucose was highly catalyzed by NiNPs. The catalytically anodic currents were linearly increased in proportion to the glucose concentration over the 0~6.15 mM range at 650 mV versus Ag/AgCl.

Development of a Simulation Prediction System Using Statistical Machine Learning Techniques (통계적 기계학습 기술을 이용한 시뮬레이션 결과 예측 시스템 개발)

  • Lee, Ki Yong;Shin, YoonJae;Choe, YeonJeong;Kim, SeonJeong;Suh, Young-Kyoon;Sa, Jeong Hwan;Lee, JongSuk Luth;Cho, Kum Won
    • KIPS Transactions on Software and Data Engineering
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    • v.5 no.11
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    • pp.593-606
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    • 2016
  • Computer simulation is widely used in a variety of computational science and engineering fields, including computational fluid dynamics, nano physics, computational chemistry, structural dynamics, and computer-aided optimal design, to simulate the behavior of a system. As the demand for the accuracy and complexity of the simulation grows, however, the cost of executing the simulation is rapidly increasing. It, therefore, is very important to lower the total execution time of the simulation especially when that simulation makes a huge number of repetitions with varying values of input parameters. In this paper we develop a simulation service system that provides the ability to predict the result of the requested simulation without actual execution for that simulation: by recording and then returning previously obtained or predicted results of that simulation. To achieve the goal of avoiding repetitive simulation, the system provides two main functionalities: (1) storing simulation-result records into database and (2) predicting from the database the result of a requested simulation using statistical machine learning techniques. In our experiments we evaluate the prediction performance of the system using real airfoil simulation result data. Our system on average showed a very low error rate at a minimum of 0.9% for a certain output variable. Using the system any user can receive the predicted outcome of her simulation promptly without actually running it, which would otherwise impose a heavy burden on computing and storage resources.

Improvement in Mechanical Strength of α-Alumina Hollow Fiber Membrane by Introducing Nanosize γ-Alumina Particle as Sintering Agent (소결조제로 나노크기 γ-알루미나 입자의 도입에 따른 α-알루미나 중공사 분리막의 기계적 강도 향상)

  • Kim, Yong-Bin;Kim, Min-Zy;Arepalli, Devipriyanka;Cho, Churl-Hee
    • Membrane Journal
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    • v.32 no.2
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    • pp.150-162
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    • 2022
  • In the field of water treatment and pharmaceutical bio an alumina hollow fiber membrane used for mixture separation. However, due to the lack of strengths it is very brittle to handle and apply. Therefore, it is necessary to study and improve the bending strength of the membrane to 100 MPa or more. In this study, as the mixing ratio of the nano-particles increased to 0, 1, 3, and 5 wt%, the viscosity of the fluid mixture increased. The pore structure of the hollow membrane produced by interrupting the diffusion exchange rate of the solvent and non-solvent during the spinning process suppresses the formation of the finger-like structure and gradually increases the ratio of the sponge-like structure to improve the membrane mechanical strength to more than 100 MPa. As a result, an interparticle space was ensured to improve the porosity of the sponge-like structure with high permeability, and it showed excellent N2 permeability of about 100000 GPU and high water permeability of 3000 L/m2 h. Therefore, it can be concluded, that the addition of γ-Al2O3 nanoparticles as sintering aid is an important method to enhance the mechanical strength of the α-alumina hollow fiber membrane to maintain high permeability.