• Title, Summary, Keyword: Energy dependence

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Temperature Dependence of Energy Gap and Thermodynamic Function Properties of Coblt-doped $Cd_4GeS_6$Single Crystals (Cobalt를 첨가한 $Cd_4GeS_6$ 단결정에서 Energy Gap의 온도의존성 및 열역학적 함수 추정)

  • 김덕태
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.11 no.9
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    • pp.693-699
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    • 1998
  • In this work $Cd_4GeS_6:Co^{2+}$(0.5mole%) single crystals were grown by the chemical transporting reactiov(CTR) method using high purity(6N) elements. The grown single crystals crystallized in a monoclinic structure(space group Cc). The direct optical energy gap of this single crystals was found to be 2.445eV at 300K and the temperature dependence of optical energy gap was fitted well to Varshni equation. But at temperatures lower than 70K an anomalous temperature dependence of the optical energy gap was obtained. This anomalous temperature dependence accored well with the anomalous temperature dependence of the unit cell volume. Also, the entropy, enthalpy and heat capacity were deduced from the temperature dependence of optical energy gaps.

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Evaluation of OSLD and EBT3 film for dose, energy, and angular dependence (OSLD와 EBT3 필름의 선량, 에너지, 방향의존성에 대한 평가)

  • Lee, Ju-seong;Kang, Bo-ram;Kwon, Hyeon-Kyung;Park, Ji-Young;Kim, Ju-Hye;Choi, Young-Se;Kim, Daehong
    • The Korean Journal of Food & Health Convergence
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    • v.4 no.1
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    • pp.15-22
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    • 2018
  • A radiation dosimeter is important to assess quality assurance (QA) of radiation therapy devices and to estimate the radiation dose in vivo dosimetry. Recently, optically stimulated luminescence detector (OSLD) is widely used in clinical filed. Therefore, the purpose of this study is to evaluate dose, energy, and angular dependence of OSLD and EBT3 film. The absorbed dose in clinical linear accelerator (Linac) beam is calibrated for dose per monitor unit (MU). Dose, energy, and angular dependence of OSLD and EBT3 film are estimated after the calibration procedure. The absorbed dose is measured at 50, 100, 150, and 200 cGy in an 6 MV X-ray beam for dose dependence. A dose of 150 cGy is delivered to OSLD and EBT3 film with 6 and 10 MV photon energies for energy dependence. For measurements of angular dependence, angular positions of gantry are $0^{\circ}{\pm}80^{\circ}$ with 6 MV at 150 cGy. The results of dose dependence is linear for OSLD and EBT3 film. For the results of energy dependence, errors were 0.39% and 0.03% for OSLD and EBT3 film, respectively. The results of dose for angular is decreased from $0^{\circ}$ to ${\pm}80^{\circ}$ for both OSLD and EBT3 film. When angle of $0^{\circ}$ is normalized to 1, and the dose is decreased to 60 and 66% at $80^{\circ}$ for OSLD and EBT3 film, respectively. Dose and energy dependence of OSLD and EBT3 film are measured within the recommendation of manufacturer. Angular dependence is increased from $0^{\circ}$ to ${\pm}80^{\circ}$ for OSLD and EBT3 film. The characteristics of OSLD and EBT3 film are similar and expected to useful for clinical field.

An Energy Efficiency Analysis of Korea based on the Energy Dependence and Independence rate (에너지순수입의존도 및 에너지자립도 지표를 통한 우리나라 에너지경제효율분석)

  • Min, Yun-Ji
    • International Commerce and Information Review
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    • v.16 no.2
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    • pp.199-218
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    • 2014
  • The study was focused on the Energy Efficiency of Korea. Thus this study calculates Energy Intensity and Energy Dependence, Energy Independence rate using data Korea Energy Statistics. This study calculate 'Energy Intensity', 'Energy Dependence', 'Energy Independence rate', which is making use of the Gross Domestic product, Energy Consumption, Energy Export and Import, Energy Gross Input. The analysis of the pater suggests that this goal can be achieved throuth improved efficiency of Energy consumption and Energy Independence.

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Fundamental Study of nanoDot OSL Dosimeters for Entrance Skin Dose Measurement in Diagnostic X-ray Examinations

  • Okazaki, Tohru;Hayashi, Hiroaki;Takegami, Kazuki;Okino, Hiroki;Kimoto, Natsumi;Maehata, Itsumi;Kobayashi, Ikuo
    • Journal of Radiation Protection and Research
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    • v.41 no.3
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    • pp.229-236
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    • 2016
  • Background: In order to manage the patient exposure dose in X-ray diagnosis, it is preferred to evaluate the entrance skin dose; although there are some evaluations about entrance skin dose, a small number of report has been published for direct measurement of patient. We think that a small-type optically stimulated luminescence (OSL) dosimeter, named nanoDot, can achieve a direct measurement. For evaluations, the corrections of angular and energy dependences play an important role. In this study, we aimed to evaluate the angular and the energy dependences of nanoDot. Materials and Methods: We used commercially available X-ray diagnostic equipment. For angular dependence measurement, a relative response of every 15 degrees of nanoDot was measured in 40-140 kV X-ray. And for energy dependence measurement, mono-energetic characteristic X-rays were generated using several materials by irradiating the diagnostic X-rays, and the nanoDot was irradiated by the characteristic X-rays. We evaluated the measured response in an energy range of 8.1-75.5 keV. In addition, we performed Monte-Carlo simulation to compare experimental results. Results and Discussion: The experimental results were in good agreement with those of Monte-Carlo simulation. The angular dependence of nanoDot was almost steady with the response of 0 degrees except for 90 and 270 degrees. Furthermore, we found that difference of the response of nanoDot, where the nanoDot was irradiated from the randomly set directions, was estimated to be at most 5%. On the other hand, the response of nanoDot varies with the energy of incident X-rays; slightly increased to 20 keV and gradually decreased to 80 keV. These results are valuable to perform the precise evaluation of entrance skin dose with nanoDot in X-ray diagnosis. Conclusion: The influence of angular dependence and energy dependence in X-ray diagnosis is not so large, and the nanoDot OSL dosimeter is considered to be suitable dosimeter for direct measurement of entrance surface dose of patient.

Evaluation for Performance of a Military Radiation Detecter PDR-1K : Focused on Dependence of Angular and Energy (군사용 방사선 계측기 PDR-1K 반응도 평가 : 방향 및 에너지 의존성을 중심으로)

  • Park, Wonseok;Choi, Junhyuk;Jung, Doyoung;Kim, Jango;Min, Byungin
    • Journal of the Korea Institute of Military Science and Technology
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    • v.20 no.2
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    • pp.300-305
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    • 2017
  • In this paper, we performed a evaluation for angular and energy dependence of military radiation detector PDR-1K. Its measuring range is divided into two section, low and high, and each range has a GM tube separately owing to broad scale. We observed a change in relative angular reactivity within 0.928 ~ 1.188 in low range and within 0.743 ~ 1.000 in high range from $-90^{\circ}$ to $+90^{\circ}$. The evaluation for energy dependence appeared a relative reactivity within 0.892 ~ 1.000 above 83 keV. This means PDR-1K isn't possible to use below 83 keV of radiation energy. It is possible to provide response information to user and to increase reliability of radiation measurement through this paper.

Displacement and Velocity Dependence of Clamped Shape Metallic Dampers (꺽쇠형 강재 댐퍼의 변위 및 속도 의존성)

  • Lee, Hyun Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.2
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    • pp.62-70
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    • 2013
  • The purpose of this study is the displacement and velocity dependence evaluation of clamped shape metallic damper, which were evaluated superior in energy dissipation capacity than straight type slit damper. For this purpose, 6 metallic damper specimens are prepared and dependence test are performed. Test variables are displacement dependence and velocity dependence. According to displacement dependence test results, larger target displacement (50mm) shows lower cyclic numbers and cumulated energy dissipated area than lower target displacement (25mm). Also it shows higher strength and early failure than short target displacement. In velocity dependence evaluation, fast target velocity (60mm/sec) shows lower cyclic numbers and cumulated energy dissipated area than slow target velocity (40mm/sec). Therefore the hysteresis dependence of metallic damper were evaluated as close relation to the loading displacement and velocity conditions.

Strain Dependence of Adsorption Energy of Single Layer MoS2: Possibility of Catalytic Usage

  • Jeon, Bu-Gyeong;Lee, Chang-Hui
    • Proceeding of EDISON Challenge
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    • pp.355-356
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    • 2016
  • It is shown that the maximum value of exchange current is obtained where hydrogen adsorption energy is near 0. This enables to estimate catalytic efficiency of a material with hydrogen adsorption energy, which is relatively easier to calculate with density fuctional theory (DFT) method. Strain dependence of the adsorption energy was studied with DFT method and adsorption energy of 0.04 eV per hydrogen atom is obtained at 30% strain.

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Energy barrier of nanomagnet with perpendicular magnetic anisotropy

  • Song, Kyungmi;Lee, Kyung-Jin
    • Proceedings of the Korean Magnestics Society Conference
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    • pp.120-121
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    • 2014
  • We investigate the field-dependence of energy barrier for various cell diameters and two type of geometry through the NEB method. We find that the energy barrier can depend strongly on the cell size when the switching is governed by the domain wall motion. Moreover we also examine the cell size dependence of energy barrier for two type of cell geometry. In the presentation, we will discuss the effect of domain wall formation and more various cell size on the energy barrier in detail.

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Dependency Evaluation According to Damper Strut Type (댐퍼 스트럿 형상에 따른 의존성 평가)

  • Lee, Hyun-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.18 no.5
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    • pp.78-86
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    • 2014
  • The purpose of this study is the displacement and velocity dependence evaluation of I type and S type metallic dampers. For this purpose, 12 metallic damper specimens are prepared and dependence test are performed. Test variables are strut type, displacement and velocity dependence. From the evaluation results of dependence tests, number of cycles are fully exceeded than minimum 5 cycles described in ASCE 7-10. According to displacement dependence test results, larger target displacement (50mm) shows lower cyclic numbers and cumulated energy dissipated area than lower target displacement (25mm). Also it show higher strength and early failure than short target displacement. In velocity dependence evaluation, fast target velocity (60mm/sec) shows lower cyclic numbers and cumulated energy dissipated area than target velocity (40mm/sec). As a results of basic properties, dependence evaluation and cumulated energy dissipated area evaluation, dependence capacity of S type metallic damper is far superior than I type.

Analysis on the Dependence Structure between Energy Price and Economic Uncertainty Using Copula Model (Copula 모형을 이용한 에너지 가격과 경제적 불확실성 사이의 의존관계 분석)

  • Kim, Bu-Kwon;Choi, Ki-Hong;Yoon, Seong-Min
    • Environmental and Resource Economics Review
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    • v.29 no.2
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    • pp.145-170
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    • 2020
  • This study analyzes the dependence structure between energy (crude oil, natural gas, coal) prices and economic (real and financial) uncertainty. Summary of the results of the dependence structure between energy prices and economic uncertainty analysis is as follows. First, the results of model selection show that the BB7 copula model for the pair of crude oil price and economic uncertainty, the Joe copula model for the pair of natural gas price and economic uncertainty, and the Clayton copula model for the pair of coal price and economic uncertainty were chosen. Second, looking at the dependency structure, it showed that the pair of energy (crude oil, natural gas, coal) prices and real market uncertainty show positive dependence. Whereas, the only pair of financial market uncertainty-crude oil price shows positive dependency. In particular, crude oil price was found to have the greatest dependence on economic uncertainty. Third, looking at the results of tail dependency, the pair of real market uncertainty-crude oil price and pair of real market uncertainty-natural gas price have an asymmetric relationship with the upper tail dependency. It can be seen that the only pair of financial market uncertainty-crude oil represents asymmetric relationships with the upper tail dependencies. In other words, combinations with asymmetric relationships have shown strong dependence when negative extreme events occur. On the other hand, tail dependence between economic uncertainty and coal price be not found.