• Title/Summary/Keyword: sensor scanning

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Ambient Fine and Ultrafine Particle Measurements and Their Correlations with Particulate PAHs at an Elementary School Near a Highway

  • Song, Sang-Hwan;Paek, Do-Myung;Lee, Young-Mee;Lee, Chul-Woo;Park, Chung-Hee;Yu, Seung-Do
    • Asian Journal of Atmospheric Environment
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    • v.6 no.2
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    • pp.96-103
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    • 2012
  • Ambient particulate matter (PM) and particle-bound polycyclic aromatic hydrocarbon (PAH) concentrations were measured continuously for 70 days at a Korean elementary school located near a highway. The $PM_{10}$, $PM_{2.5}$, and $PM_1$ values were measured with a light-scattering, multi-channel, aerosol spectrometer (Grimm, Model 1.107). The number concentrations of the particles were measured using a scanning mobility particle sizer and counter (SMPS+C) which counted particles from 11.1 to 1083.3 nm classified in 44 channels. Particle-bound PAHs were measured with a direct reading, photoelectric aerosol sensor. The daily $NO_2$, $SO_2$, and CO concentrations were obtained from a national air-monitoring station located near the school. The average concentrations of $PM_{10}$, $PM_{2.5}$, and $PM_1$ were 75.3, 59.3, and $52.1{\mu}g/m^3$, respectively. The average number concentration of the ultrafine particles (UFPs) was $46,307/cm^3$, and the averaged particle-bound PAHs concentration was $17.9ng/cm^3$ during the study period. The ambient UFP variation was strongly associated with traffic intensity, particularly peak concentrations during the traffic rush hours. Particles <100 nm corresponded to traffic-related pollutants, including PAHs. Additional longterm monitoring of ambient UFPs and high-resolution traffic measurements should be carried out in future studies. In addition, transient variations in the ambient particle concentration should be taken into consideration in epidemiology studies in order to examine the short-term health effects of urban UFPs.

Implementation for Automatic Inspection System on Ventilating Electronic Device Based on Reliability Improvement (신뢰성 향상 기반의 송풍전자장치 자동검사 시스템 구현)

  • Do, Nam Soo;Ryu, Kwang Ryol
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.6
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    • pp.1155-1160
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    • 2017
  • This paper describes a system implementation for the automatic inspection on the ventilating electronic device based on the reliability improvement. To be enhancement, the inspection error is minimized by the automatic inspection system on the ventilating apparatuses against the manual inspecting system. The system consists of the control system, software structure and monitoring system to be scanning the inspection processing. The inspection system for reliability improvement is evaluated in Gage Repeatability and Reproducibility. The experimental results are improved about 2 times inspecting speed, measured error ${\pm}0.02V$, effectiveness of discriminating performance 15%, missing probability 17% and false alarm probability 12% respectively in comparing with the manual inspection based on the wind pressure sensor. The system will be also improved more by making database and product bar codes for the total quality control system to the effective reliability enhancement in the future.

Fabrication and H2S Sensing Property of Nickel Oxide and Nickel Oxide-Carbon Nanotube Composite (산화니켈 및 탄소나노튜브/산화니켈 복합체 가스센서의 제작과 황화수소 감지 특성)

  • Yang, Haneul;Chinh, Ngyuen Duc;Hieu, Ngyuen Minh;Park, Jihwan;Hong, Soonhyun;yun, Hongkwan;Kim, Chunjoong;Kim, Dojin
    • Korean Journal of Materials Research
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    • v.28 no.8
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    • pp.466-473
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    • 2018
  • Nickel oxide(NiO) thin films, nanorods, and carbon nanotube(CNT)/NiO core-shell nanorod structures are fabricated by sputtering Nickel at different deposition time on alumina substrates or single wall carbon nanotube templates followed by oxidation treatments at different temperatures, 400 and $700^{\circ}C$. Structural analyses are carried out by scanning electron microscopy and x-ray diffraction. NiO thinfilm, nanorod and CNT/NiO core-shell nanorod structurals of the gas sensor structures are tested for detection of $H_2S$ gas. The NiO structures exhibit the highest response at $200^{\circ}C$ and high selectivity to $H_2S$ among other gases of NO, $NH_3$, $H_2$, CO, etc. The nanorod structures have a higher sensing performance than the thin films and carbon nanotube/NiO core-shell structures. The gold catalyst deposited on NiO nanorods further improve the sensing performance, particularly the recovery kinetics.

Optical properties of Al doped ZnO Nanofibers Prepared by electrospinning (전기방사를 이용한 Al이 첨가된 ZnO 나노섬유의 제조 및 광학 특성평가)

  • Song, Chan-Geun;Yoon, Jong-Won
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.21 no.5
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    • pp.205-209
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    • 2011
  • Zinc oxide has semi-conductivity and super conductivity characteristics. It can be used optically and is applied on many areas such as gas sensor, solar cell and optical waveguide. In this paper, to improve optical characteristics of ZnO, aluminum was added on zinc oxide. Zinc oxide and aluminum zinc oxide was fabricated as nano fiber form. ZnO solution was created by mixing poly vinyl pyrrolidone, ethyl alcohol, and zinc acetate. An Al doped ZnO was created by adding aluminum solution to ZnO sol. By applying these sols on electro spinning method, nano fibers were fabricated. These fibers are heat treated at 300, 500, and $700^{\circ}C$ degrees and were analyzed with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) to examine the nano structures. TGA and DSC measurement was also used to measure the change of mass and calorie upon temperature change. The absorbance of ZnO and Al-doped ZnO was carried out by UV-vis measurement.

Moon Imaging for the Calibration of the COMS Meteorological Imager (천리안 위성의 기상탑재체 보정을 위한 달 영상 획득 방안)

  • Park, Bong-Kyu;Yang, Koon-Ho
    • Aerospace Engineering and Technology
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    • v.9 no.2
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    • pp.44-50
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    • 2010
  • COMS accommodates multiple payloads; Meteorological Image(MI), Ocean Color Imager(GOCI) and Ka-band communication payloads. In order to improve the quality of MI visible channel, the moon image has been taken into account as backup reference in addition to Albedo monitoring. However, obtaining the moon image by adding special mission schedule is not recommended after IOT, because we may miss chances to obtain meteorological images during the time slots for special imaging. As an alternative solution, an approach extracting moon image from MI FD(Full Disk) image has been proposed when the moon is positioned near to the earth. However, prediction of acquisition time of moon image is somewhat difficult as the moon moves while the MI is scanning type sensor. And the moon can not be seen when it is behind the earth or outside of FD field of view. This paper discusses how effectively the moon can be detected by the MI FD imaging. For that purpose, this paper describes an approach taken to predict the time when the moon image is achievable and then introduces the results obtained from computer simulation.

Effect of the hetero-epitaxial ZnO buffer layer for the formation of As-doped ZnO thin films (Hetero-epitaxial ZnO 버퍼층이 As-doped ZnO 박막의 증착조건에 미치는 영향)

  • Lee, Hong-Chan;Choi, Won-Kook;Shim, Kwang-Bo;Oh, Young-Jei
    • Journal of Sensor Science and Technology
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    • v.15 no.3
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    • pp.216-221
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    • 2006
  • ZnO thin films prepared by PLD method exhibit an excellent optical property, but may have some problems such as incomplete surface roughness and crystallinity. In this study, undoped ZnO buffer layers were deposited on (0001) sapphire substrates by ultra high vacuum pulse laser deposition (UHV-PLD) and molecular beam epitaxy (MBE) methods, respectively. After post annealing of ZnO buffer layer, undoped ZnO thin films were deposited under different oxygen pressure ($35{\sim}350$ mtorr) conditions. The Arsenic-doped (1, 3 wt%) ZnO thin layers were deposited on the buffer layer of undoped ZnO by UHV-PLD method. The optical property of the ZnO thin films was analyzed by photoluminescence (PL) measurement. The ${\theta}-2{\theta}$ XRD analysis exhibited a strong (002)-peak, which indicates c-axis preferred orientation. Field emission-scanning electron microscope (FE-SEM) revealed that microstructures of the ZnO thin films were varied by oxygen partial pressure, Arsenic doping concentration, and deposition method of the undoped ZnO buffer layer. The denser and smoother films were obtained when employing MBE-buffer layer under lower oxygen partial pressure. It was also found that higher Arsenic concentration gave the enhanced growing of columnar structure of the ZnO thin films.

The characteristics of Pt thin films prepared by DC magnetron sputter (DC Magnetron Sputter로 제조된 Pt 박막의 특성)

  • Na, Dong-Myong;Kim, Young-Bok;Park, Jin-Seong
    • Journal of Sensor Science and Technology
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    • v.16 no.2
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    • pp.159-164
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    • 2007
  • Thin films of platinum were deposited on a $Al_{2}O_{3}/ONO(SiO_{2}-Si_{3}N_{4}-SiO_{2})/Si$-substrate with an 2-inch Pt(99.99 %) target at room temperature for 20, 30 and 60 min by DC magnetron sputtering, respectively X-ray diffract meter (XRD) was used to analyze the crystallanity of the thin films and field emission scanning electron microscopy (FE-SEM) was employed for the investigation on crystal growth. The densification and the grain growth of the sputtered films have a considerable effect on sputtering time and annealing temperatures. The resistance of the Pt thin films was decreased with increasing deposition time and sintering temperature. Pt micro heater thin film deposited for 60 min by DC magnetron sputtering on an $Al_{2}O_{3}$/ONO-Si substrate and annealed at $600^{\circ}C$ for 1 h in air is found to be a most suitable micro heater with a generation capacity of $350^{\circ}C$ temperature and 645 mW power at 5.0 V input voltage. Adherence of Pt thin film and $Al_{2}O_{3}$ substrate was also found excellent. This characteristic is in good agreement with the uniform densification and good crystallanity of the Pt film. Efforts are on progress to find the parameters further reduce the power consumption and the results will be presented as soon as possible.

Enhanced Stretchability of Gold and Carbon Nanotube Composite Electrodes (Au와 탄소나노튜브 복합체 전극의 연성 향상)

  • Woo, Jung-Min;Jeon, Joo-Hee;Kang, Ji-Yeon;Lee, Tae-Il;Myoung, Jae-Min
    • Korean Journal of Materials Research
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    • v.21 no.3
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    • pp.133-137
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    • 2011
  • Gold have been used as an electrode materials having a good mechanical flexibility as well as electrical conductivity, however the stretchability of the gold on a flexible substrate is poor because of its small elastic modulus. To overcome this mechanical inferiority, the reinforcing gold is necessary for the stretchable electronics. Among the reinforcing materials having a large elastic modulus, carbon nanotube (CNT) is the best candidate due to its good electrical conductivity and nanoscale diameter. Therefore, similarly to ferroconcrete technology, here we demonstrated gold electrodes mechanically reinforced by inserting fabrics of CNTs into their bodies. Flexibility and stretchability of the electrodes were determined for various densities of CNT fabrics. The roles of CNTs in resisting electrical disconnection of gold electrodes from the mechanical stress were confirmed using field emission scanning electron microscope and optical microscope. The best mechanical stability was achieved at a density of CNT fabrics manufactured by 1.5 ml spraying. The concept of the mechanical reinforced metal electrode by CNT is the first trial for the high stretchable conductive materials, and can be applied as electrodes materials in various flexible and stretchable electronic devices such as transistor, diode, sensor and solar cell and so on.

A Study on Stereo Visualization of the X-ray Scanned Image Based on Volume Reconstruction (볼륨기반 X-선 스캔영상의 3차원 형상화 연구)

  • Lee, Nam-Ho;Park, Soon-Yong;Hwang, Young-Gwan;Park, Jong-Won;Lim, Yong-Gon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.15 no.7
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    • pp.1583-1590
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    • 2011
  • As the existing radiation scanning systems use 2-dimensional radiation scanned images, the low accuracy has been pointed out as a problem of it. This research analyzes the applicability of the stereo image processing technique to X-ray scanned images. Two 2-dimensional radiation images which have different disparity values are acquired from a newly designed stereo image acquisition system which has one additional line sensor to the conventional system. Using a matching algorithm the 3D reconstruction process which find the correspondence between the images is progressed. As the radiation image is just a density information of the scanned object, the direct application of the general stereo image processing techniques to it is inefficient. To overcome this limitation of a stereo image processing in radiation area, we reconstruct 3-D shapes of the edges of the objects. Also, we proposed a new volume based 3D reconstruction algorithm. Experimental results show the proposed new volume based reconstruction technique can provide more efficient visualization for cargo inspection. The proposed technique can be used for such objects which CT or MRI cannot inspect due to restricted scan environment.

Comparison of Friction and Wear Characteristics of Thin Film Coatings Using Tribotesters at Atmospheric/Vacuum Conditions (대기압/진공 조건의 트라이보 시험기를 이용한 박막 코팅의 마찰/마모 특성 비교)

  • Kim, Hae-Jin;Kim, Dae-Eun;Kim, Chang-Lae
    • Tribology and Lubricants
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    • v.35 no.6
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    • pp.389-395
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    • 2019
  • In various industries, thin film coatings are used to improve friction and wear characteristics. Various types of tribotesters are used to evaluate the friction and wear characteristics of such thin film coatings. In this study, we fabricated a micro-tribotester and Tribo-scanning electron microscopy (SEM) to compare the friction and wear characteristics of copper (Cu) coatings under an atmospheric pressure and a vacuum condition, respectively. The reliability of the different types of tribotesters was evaluated by performing calibrations for the sensor to measure the friction forces and normal loads. Using the two different types of devices, the friction and wear tests are conducted at the same experimental conditions excluding environment conditions such as the atmospheric pressure and vacuum condition. The friction coefficient at the vacuum condition is lower than at the atmospheric pressure. This difference in friction characteristics is due to the fact that wear phenomena occur differently according to the atmospheric pressure and vacuum condition. At the atmospheric pressure, the abrasive wear is the main wear mechanism. At the vacuum condition, the adhesive wear is the main wear mechanism. The reason for the difference in the wear mechanism of the Cu coating at the atmospheric pressure and the vacuum condition is that the oxidation phenomenon, which does not appear at the vacuum condition, occurs at the atmospheric pressure; therefore, the characteristics of the Cu coating change accordingly.