• Title/Summary/Keyword: Rays

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The Characteristics os Water Quality of Tap water and Far-infrared rays mineral water (수돗물과 원적외선 기능수의 수질 특성의 비교)

  • 백우현
    • Journal of Environmental Science International
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    • v.9 no.5
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    • pp.423-428
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    • 2000
  • The characteristics of Far-infrared rays mineral water(FIR water) have been compared to the tap water by means of relationship between FIR water and Nuclear Magnetic Resonance spectroscopy(NMR), FIR water and thermography FIR water and velocity of blood FIR-water and pH, FIR water and dissolved oxygen(DO), FIR water and Oxidation-Reduction Potential(ORP) using the development FIR water purification of grand prix system. From the experimental result are quite satisfactory when compared with the tap water. Also the FIR water were evaluated to see if those are tasty and healthy using the Hashimoto's Mineral Balance Index. As a result FIR-water was found as tasty and healthy.

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Descriptions of the Wood Anatomy and Safranine Impregnation in Gmelina arborea Roxb. from Bangladesh

  • Ahmed, Sheikh Ali;Chun, Su-Kyoung
    • Journal of the Korea Furniture Society
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    • v.18 no.2
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    • pp.100-105
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    • 2007
  • In this report, we describe the anatomical features of Gmelina arborea Roxb. belong to the genera of Verbenaceae native to Bangladesh and safranine penetration depth in radial and longitudinal directions. The wood of this species was characterized mostly by distinct growth ring boundaries, diffuse-porous, simple perforations, alternate non-vestured intervessel pits, and relatively short vessel elements and medium fibers. Thin to thick walled septate fibers with simple to minutely bordered pits are confined to the radial walls. Tyloses are common. They are paratracheal axial parenchyma vascicnetric and confluent. Rays not higher than 1milimeter are found, and larger rays commonly 4 to 5 seriate are dominantly present, as are multi seriate rays composed of a procumbent ray with 1 row of square or upright cells. Acicular crystals are present in ray cells. Another experiment was taken under consideration to observe the liquid penetration depth in longitudinal and radial directions using safranine. It was found that safranine penetrated easily in longitudinal direction and sapwood was more permeable than heartwood.

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A Study on the Surface Degradation Properties of Epoxy / Glass fiber Treated with Ultraviolet Rays (자외선 처리된 Epoxy/Glass Fiber의 표면 열화 특성에 관한 연구)

  • Lee, Baek-Su;Lee, Deok-Chul
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.48 no.2
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    • pp.86-91
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    • 1999
  • In order to analyse the degradation process of epoxy/glass fiber for outdoor condition, FRP laminate was exposed to the wavelength of ultraviolet rays and evaluated by comparing contact angle, surface resistivity, surface potential decay, and ESCA spectrum respectively. As irradiation energy are increased, the surface properties were steeply decreased in the range of 300[nm]. But the measured values within the scope of400[nm]∼440[nm] showed a increase as compared with the untreated ones. Also, fromthe result of ESCA spectrum, it was confirmed plenty of oxygen groups on the spot showing the maximum decrease of surface properties and the existence of ether groups on the surface of coloring phase. We can conclude that the degradation phenomena on the surface of epoxy composites are dominated by the induction of ester and carboxyl groups.

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Analysis of Maximum Solar Radiation on Inclined Surfaces in Korea (국내 최대 경사면일사량 분석)

  • Jo, Dok-Ki;Yun, Chang-Yeol;Kim, Kwang-Deuk;Kang, Young-Heack
    • 한국태양에너지학회:학술대회논문집
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    • 2009.04a
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    • pp.3-7
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    • 2009
  • The amount of incident rays over inclination according to direction has been widely utilized as important data in installing solar thermal systems. To optimize the incident solar radiation, the slope, that is the angle between the plane surface in question and the horizontal, and the solar azimuth angles are needed for these solar thermal systems. This is because the performance of the solar thermal systems in much affected by angle and direction of incident rays. Recognizing that factors mentioned above are of importance, actual experiment on the moving route of the sun have been performed in this research to obtain the angle of inclination with which the maximum incident rays can be absorbed. After all, the standard for designing highly optimized solar thermal systems will be provided for designers and employees working in the solar collector related industries.

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$\gamma$-선 Radiography에 있어서의 피사체 산란선에 관한 연구

  • 허남;야고이명
    • Nuclear Engineering and Technology
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    • v.4 no.3
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    • pp.223-228
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    • 1972
  • In the radiography, of thick materials the scattered rays from an object are one of major causes to reduce the quality of the radiographic image on the film. To determine the rate of scattering of incident gamma rays by an objective specimen, film blacknesses are measured for various slit widths. For each measurement, the changes of a penetrameter's sensitivity are also evaluated. It is observed that the fault-detectability can be improved by reducing the slit width when the fault detectability deteriorates due to the increase in scattered gamma rays by thicker samples. This experiment has been carried out with the iron specimens and $^{60}$ Co source.

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X-ray and gamma ray shielding behavior of concrete blocks

  • Hernandez-Murillo, Christian Geovanni;Contreras, J. Rafael Molina;Escalera-Velasco, Luis Alberto;de Leon-Martineza, Hector Asael;Rodriguez-Rodriguez, Jose Antonio;Vega-Carrillo, Hector Rene
    • Nuclear Engineering and Technology
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    • v.52 no.8
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    • pp.1792-1797
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    • 2020
  • The shielding characteristics of two concrete blocks, widely used in the building industry in Mexico have been determined. These characteristics include the mass interaction coefficients, the linear attenuation coefficients and the half-value layers. The energy-dispersed X-ray fluorescence shows that the percentage mass content of each atom in the sample, and the atomic volume of the constituent elements of a material, plays an important role in its shielding capabilities. The total linear attenuation coefficients and the half-value layers were analyzed for a set of photon energies related to X-rays for diagnosis and cancer treatment with linear accelerators. Our results show that the concrete blocks have similar photon attenuation coefficients than the Portland concrete and better features than gypsum.

RESULTS FROM THE YOHKOH SATELLITE

  • WATANABE TETSUYA
    • Journal of The Korean Astronomical Society
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    • v.29 no.spc1
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    • pp.291-294
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    • 1996
  • The .Japanese sun observing satellite, Yohkoh, has been operational for five years and her scientific instruments are still in good condition. They have revealed ample of evidences that solar flares were triggered by magnetic reconnection, which was, for the first time, clearly indicated to take place in the solar corona. Cusp structures in soft X-rays and a new type of hard X-ray sources at the top of flaring loops have strongly supported the scenario originally proposed by C-S-H-KP. Nonthermal energy input in hard X-rays and thermal energy estimated from soft X-rays are fundamentally consistent with the interpretation of thick-target and chromospheric-evaporation models (Neupert effect). X-ray jets, another discovery of Yohkoh, were also associated with magnetic reconnection, as a result of the interaction of emerging fluxes with pre-existing coronal loops. Temperature structures of active regions, quiet sun, and coronal holes had very dynamic differential-emission-measure (DEM) distributions and high-temperature tails of DEM were considered to come from the contribution of flare-like activity.

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First Record of Icelus toyamensis (Scorpaeniformes: Cottidae) from the East Sea, Korea

  • Song, Young Sun;Kim, Jin-Koo;Ryu, Jung-Hwa;Kim, Hyeon-Ju;Kweon, Seon-Man;Choi, Seung-Ho
    • Animal Systematics, Evolution and Diversity
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    • v.28 no.4
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    • pp.304-307
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    • 2012
  • A three specimen of Icelus toyamensis, belonging to Cottidae, Scorpaeniformes, was firstly collected from the East Sea, Korea during 2007-2009. We herein described the species as the first record from Korea on the basis of these specimens. Icelus toyamensis is characterized by the following morphological combinations: spinous scales absent on the base of dorsal fin; small ctenoid scales scattered on body sides; gill rakers are short, tubular, and relatively broad; the uppermost preopercular spine is sharp and simple; dorsal fin rays VIII-IX, 20-21; anal fin soft rays 18-19; pectoral fin rays 18, and vertebrae 40-41. New Korean name of I. toyamensis is proposed as "Min-jul-ga-si-hoet-dae."

Study of Extensive air shower simulation

  • Roh, Soon-Young;Kim, Ji-Hee;Ryu, Dong-Su;Kang, Hye-Sung;Kasahara, Katuaki;Kido, Eiji;Taketa, Akimichi
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.2
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    • pp.57.2-57.2
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    • 2010
  • Cosmic rays with energy exceeding 10^18eV are referred to as Ultra high energy cosmic rays (UHECRs). UHECR experiments have utilized air shower simulations to estimate the properties of cosmic rays. Telescope array (TA) experiment has used COSMOS and CORSIKA mainly; the Monte Carlo codes of CORSIKA and COSMOS simulate the evolution of extensive air showers in the atmosphere initiated by photons, hadrons or nuclei UHECRs. We compare the simulations from CORSIKA and COSMOS. Comparison has shown noticeable differences at the ground distributions, longitudinal distributions, Calorimetric energy, and Xmax value. The implications of our results are discussed.

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Physical mechanism of gamma-ray bursts: recent breakthroughs

  • Uhm, Z. Lucas;Zhang, Bing;Racusin, Judith
    • The Bulletin of The Korean Astronomical Society
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    • v.43 no.1
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    • pp.39.1-39.1
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    • 2018
  • Although it is agreed that the gamma-ray bursts (GRBs) invoke highly relativistic jets with bulk Lorentz factors of a few hundreds, the exact physical mechanism producing such powerful gamma-rays still remains debated. Three outstanding and important questions in the field concern (1) the composition of GRB jets (i.e., matter-dominated vs Poynting-flux-dominated), (2) the involved radiative process responsible for the observed gamma-rays (i.e., synchrotron mechanism vs photospheric radiation), and (3) the distance of the emitting region from the central engine where the prompt gamma-rays are released (i.e., ~10^12 cm vs 10^14 cm vs 10^16 cm). I will present recent important breakthroughs that we have made, which answer these three questions.

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