• Title/Summary/Keyword: radiometer

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A CLINICAL STUDY ON THE MAINTENANCE OF LIGHT INTENSITY OF VISIBLE-LIGHT CURING MACHINES FOR THE POLYMERIZATION OF COMPOSITE RESINS (복합레진 중합용 가시광선 광중합기의 적정 광강도 유지를 위한 임상적 고찰)

  • Lee, Dong-Soo;Jeong, Tae-Sung;Kim, Shin
    • Journal of the korean academy of Pediatric Dentistry
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    • v.28 no.3
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    • pp.363-368
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    • 2001
  • It is well known that numerous factors influence the light output of curing units, but many dentists are un aware that the output of their curing lights are inadequate. This study was conducted to evaluate the light in tensity of visible-light curing units in some private dental clinics and hospital dental clinics. In order to determine the maximum light intensity of the curing units, lamps, filters and fiber optic bundles, they were replaced with new ones and light intensity was remeasured. Light intensity was measured by employing a digital radiometer (EFOS model #8000, USA). Light intensity ranged in $29\sim866mW/cm^2$ (below $150mW/cm^2$ ; 17.8%, $150\sim300mW/cm^2$ : 46.6%, above $300mW/cm^2$ ; 35.6%). The replacement of the components increased the light intensity, with maximum increases of 94.8% for lamps, 82.3% for filters, 200.8% for fiber optics and 361.5% for all three parts. According to the manufacturer of radiometer, curing light is considered as unsuitable for use with a reading of above $300mW/cm^2$ by the radiometer. Applying these criteria to the present study, 64.4% of the curing units required repair or replacement. The results of this study indicated that the light intensities of the curing units used in dental practice were lower than optimum level.

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Optical Properties of Aerosol at Gongju Estimated by Ground-based Measurements Using Sky-radiometer (스카이라디오미터(Sky-radiometer)로 관측된 공주지역 에어로솔의 광학적 특성)

  • Kwak, Chong-Heum;Suh, Myoung-Seok;Kim, Maeng-Ki;Kwak, Seo-Youn;Lee, Tae-Hee
    • Journal of the Korean earth science society
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    • v.26 no.8
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    • pp.790-799
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    • 2005
  • We investigate the optical properties of aerosols over Gongju by an indirect method using the pound measurement, Sky-radiometer. The analysis period is from January to December, 2004. Skyrad. pack.3 is used to estimate the optical properties, such as the aerosol optical thickness (AOT), single scattering albedo (SSA), ${\AA}ngstron$ exponent $({\alpha})$ and size distribution, of aerosols from the ground measured radiance data. And qualify control is applied to minimize the cloud-contaminated data and improve the quality of analysis results. The 12-month average of AOT, ${\alpha}$, and SSA are 0.46, 1.14, and 0.91, respectively. The average volume spectra of aerosols shows a bi-modal distribution, the first peak at fine mode and the second peak at coarse mode. AOT and coarse particles clearly increases while SSA decreases during the Asian dust events. The optical properties of aerosols at Gongju vary with?seasons, but those are not influenced by the wind direction.

Interferometric Synthetic Aperture Millimeter-wave Radiometer for the High Resolution Imaging

  • Kim, Yong-Hoon;Choi, Jung-Hee;Kang, Gum-Sil
    • Proceedings of the KSRS Conference
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    • 1999.11a
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    • pp.122-126
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    • 1999
  • The imaging characteristics of a 2-D interferometric synthetic aperture radiometer, such as an angular resolution, depend largely on the type of an antenna array. In this paper, different array configurations of antenna are studied and compared with each array types to get more high resolution image in spatial. T-, X- and Y- types of antenna array are considered and the performances of each type are analyzed considering spatial resolution. The simulation results of candidate antenna types are presented in this paper. In case of Y-type the coverage area of the visibility function is wide and the angular resolution is high more than the others. X-type array shows the good performance for side lobe level.

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A PROJECT ON GLOBAL ENVIRONMENTAL SATELLITE DATABASE BASED ON NETWORKS

  • Takagi, Mikio
    • Proceedings of the KSRS Conference
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    • 1999.11a
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    • pp.296-298
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    • 1999
  • Five institutions, which are very active in data utilization of environmental satellites NOAA and GMS, are connected via high speed networks to construct the databases based on the observations of A AVHRR (Advanced very High Resolution Radiometer) of NOAA satellite and VISSR (Visible and Infrared Scanning Radiometer) of GMS (Geostationary Meteorological Satellite) and to create scientific data sets for land, ocean and ,atmosphere. And vegetation index, sea surface temperature, cloud distribution maps and so on are generated by high speed and huge volume data Processing for studies on long term variations of land, ocean and atmosphere in Asia. In this paper the concept of this project and the activities at the Science University of Tokyo are briefly introduced

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DESIGN OF CORRUGATED HORN ANTENNAS FOR THE SPACEBORNE RADIOMETER (DREAM) ON STSAT-2

  • Chae Chun-Sik;Kim Sung-Hyun;Zhang De-Hai;Jiang Jing-Shan;Kim Yong-Hoon
    • Proceedings of the KSRS Conference
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    • 2005.10a
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    • pp.733-736
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    • 2005
  • This paper presents the design of two antennas for the Dual-channel Radiometers for Earth and Atmosphere Monitoring (DREAM) the main payload, will be launched at NARO space center in Korea in 2007. The antennas are designed to meet stringent requirements of a very high beam efficiency, good pattern symmetry, and low VSWR, at 23.8 GHz and 37 GHz bands. Corrugated horn antennas are used. The simulation results of the electrical performance are presented.

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Measurement of Thermal Properties of SiC/C Functionally Gradient Materials by Laser Flash Method (레이저 플래쉬 방법에 의한 SiC/C계 경사기능재료의 열물성 측정)

  • Mok, Jae-Gyun;Yu, Jae-Seok
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.5
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    • pp.1679-1688
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    • 1996
  • Laser flash technique was applied to measure thermal properties of FGM made by a CVD method. System stability and reproducibility of this measuring system were proved and calibrated with glassy carbon used as reference material. Specimens was prepared by cutting FGM diagonally. Measurements were performed for a wide range of temperatures up to 1500K. Relative heat capacity of the FGM specimen was scattered with in $\pm$13% at room temperature and at high temperature above 1200K, and $\pm$3% at medium temperature range. On the other hand, thermal diffusivity data showed excellent reproducibility and stability through the whole temperature range. In conclusion, the multi-target radiometer can be applied to measure the thermal properties of non homogeneous materials like FGM.

Measurement of Radiation using Photo Diodes (광소자에 의한 일사량 측정)

  • 이남호;백성호;김기복
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.43 no.3
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    • pp.39-45
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    • 2001
  • The purpose of this study is to develop an economic and practical radiation sensor using photo diodes which is useful for estimating ET in greenhouse environment. An electronic circuit was then designed. Out put signal of photo diode is amplified with a LM318 transistor and is displayed in a LCD with value from zero to 255. The output signal was compared with that of a ready-made pyranometer. The behavior of the photo diode radiation sensor was evaluated by increasing number of photo diodes. The sensor became more reliable with increased number of photo diodes. Developed radiometer was tested with calibrated relation between pyranometer radiation and photo diode output. It was showed that the photo diodes radiometer would be applicable for the greenhouse environment.

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Study of Mechanics of Remote Sensing and Exploring Method in Layered Medium

  • Ai-lan, LAN;Sheng-wei, ZHANG;Jing-shan, Jiang
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.1356-1358
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    • 2003
  • In the paper, a method making use of the characteristics of Dyad Green Function (DGF) and Fluctuation-Dissipation Theorem to get the brightness temperature of layered medium is introduced. Based on the approach and the measured data of multi-channel radiometer and Least Square Method (LSM), the thickness of lunar soil can be retrieved. These methods are significant to study on materials on lunar surface.

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Segmentation of Millimeter-wave Radiometer Image via Classuncertainty and Region-homogeneity

  • Singh, Manoj Kumar;Tiwary, U.S.;Kim, Yong-Hoon
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.862-864
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    • 2003
  • Thresholding is a popular image segmentation method that converts a gray-level image into a binary image. The selection of optimum threshold has remained a challenge over decades. Many image segmentation techniques are developed using information about image in other space rather than the image space itself. Most of the technique based on histogram analysis information-theoretic approaches. In this paper, the criterion function for finding optimal threshold is developed using an intensity-based classuncertainty (a histogram-based property of an image) and region-homogeneity (an image morphology-based property). The theory of the optimum thresholding method is based on postulates that objects manifest themselves with fuzzy boundaries in any digital image acquired by an imaging device. The performance of the proposed method is illustrated on experimental data obtained by W-band millimeter-wave radiometer image under different noise level.

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