• Title/Summary/Keyword: Temperature Profile

Search Result 1,255, Processing Time 0.021 seconds

Understanding of the effect of charge size to temperature profile in the Czochralski method (쵸크랄스키법에서 온도 프로파일에 대한 충진사이즈의 효과에 대한 이해)

  • Baik, Sungsun;Kwon, Sejin;Kim, Kwanghun
    • Journal of the Korean Crystal Growth and Crystal Technology
    • /
    • v.28 no.4
    • /
    • pp.141-147
    • /
    • 2018
  • Solar energy has attracted big attentions as one of clean and unlimited renewable energy. Solar energy is transformed to electrical energy by solar cells which are comprised of multi-silicon wafer or mono-silicon wafer. Monosilicon wafers are fabricated from the Czochralski method. In order to decrease fabrication cost, increasing a poly-silicon charge size in one quartz crucible has been developed very much. When we increase a charge size, the temperature control of a Czochralski equipment becomes more difficult due to a strong melt convection. In this study, we simulated a Czochralski equipment temperature at 20 inch and 24 inch in quartz crucible diameter and various charge sizes (90 kg, 120 kg, 150 kg, 200 kg, 250 kg). The simulated temperature profiles are compared with real temperature profiles and analyzed. It turns out that the simulated temperature profiles and real temperature profiles are in good agreement. We can use a simulated profile for the optimization of real temperature profile in the case of increasing charge sizes.

Daytime Temperature Measuring LIDAR System by Using Rotational Raman Signal (회전 라만 신호를 이용한 낮 시간 온도측정 라이다)

  • Yoon, Moonsang;Kim, Dukhyeon;Park, Sunho;Sin, MyeongJae;Kim, Yonggi;Jung, Haedoo
    • Korean Journal of Optics and Photonics
    • /
    • v.23 no.4
    • /
    • pp.159-166
    • /
    • 2012
  • We have developed a daytime measuring rotational Raman LIDAR system for temperature measurement. To decrease the background signal from sunlight, we have designed and installed narrow band (0.5 nm) and high rejection ($10^{-6}$) rate band pass filter system using a grating and an interference filter. We calibrated our system by comparing our horizontal temperature profile and KMA (Korea Meteorological Administration) data. We have found that our temperature profile has a good correlation with KMA data within our theoretically expected variance. And we have used these calibration values in obtaining a vertical temperature distribution. To check our system, we also have compared our vertical temperature data with US standard atmospheric temperature profile. We also have compared our temperature profile with sonde data.

Improvement of Negative Bias Temperature Instability by Decoupled Plasma Nitridation Process (Decoupled Plasma Nitridation 공정 적용을 통한 Negative Bias Temperature Instability 특성 개선)

  • Park, Ho-Woo;Roh, Yong-Han
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.18 no.10
    • /
    • pp.883-890
    • /
    • 2005
  • In this paper, the established model of NBTI (Negative Bias Temperature Instability) mechanism was reviewed. Based on this mechanism, then, the influence of nitrogen was discussed among other processes. A constant concentration of nitrogen exists inside $SiO_2$ in order to prevent boron from diffusing and to increase dielectric constant. It was shown that NBTI improvement was achieved by controlling nitrogen profile. It was supposed that the existence of low activation energy of Si-N bonds at $Si-SiO_2$ interface attributes the improvement by making hydrogen prevent interface traps. It was also shown that improvement of NBTI can be achieved by more effective control of nitrogen profile. It was supposed that the maximum control of nitrogen profile can be achieved by DPN (Decoupled Plasma Nitridation) process.

Study on Coherent Anti-Stokes Raman Spectroscopy for Measuring Temperature Profile in a Flame (CARS를 이용한 화염내부 온도분포 측정연구)

  • 한재원;박승암;이은성;이충희;강경태;정석호
    • Korean Journal of Optics and Photonics
    • /
    • v.3 no.4
    • /
    • pp.266-272
    • /
    • 1992
  • A coherent anti-Stokes Raman spectroscopy (CARS) technique is applied to measure temperature profile in a flame. The CARS signal is obtained with BOXCARS phase matching to get better spatial resolution. A program routine for calculating temperature of the flame from the measured CARS spectra is studied. The routine includes the line broadening mechnism of the molecules described with a modified energy gap (MEG) law by using the perturbation theory. We have found that the temperature profile obtained with the MEG law is properly fit with the results measured with a thermocoulpe and calculated with the adiabatic theory.

  • PDF

A Calculation Model for Fuel Constituent Redistribution and Temperature Distribution on Metallic U-10Zr Fuel Slug of Liquid Metal Reactors

  • Nam, Cheol;Hwang, Woan
    • Nuclear Engineering and Technology
    • /
    • v.30 no.6
    • /
    • pp.507-517
    • /
    • 1998
  • Unlike conventional fuel types, fuel constituent redistribution and sodium intrusion into the fuel slug are the unique phenomena of the irradiated metallic fuel. A thermal calculation model on metallic U-10 wt.%Zr fuel rod for LMRs is developed with considerations given to these phenomena. The amount of constituent redistribution is estimated based on the thermotransport process. The temperature profile of fuel slug is predicted by taking into account of Zr redistribution, porosity formation and sodium logging effects. A sample calculation is performed and compared to experimental data in literature. As a result, the predicted redistribution and temperature profile are well agreed with experimental data, assuming that 15 times increment of ex-reactor diffusivity, $Q_{r}$ $^{*}$ is -50 kJ/mole and sodium is infiltrated only outside of the fuel slug. Furthermore, the redistribution effects on fuel integrity and fuel temperature profile are discussed.d.

  • PDF

Moving Temperature Profile Method for Efficient Three-Dimensional Finite Element Welding Residual Stress Analysis for Large Structures (대형구조물의 효율적 3차원 용접잔류응력해석을 위한 새로운 이동 온도 프로파일 방법)

  • Cheol Ho Kim;Jae Min Gim;Yun Jae Kim
    • Transactions of the Korean Society of Pressure Vessels and Piping
    • /
    • v.19 no.2
    • /
    • pp.75-83
    • /
    • 2023
  • For three-dimensional finite element welding residual stress simulation, several methods are available. Two widely used methods are the moving heat source model using heat flux and the temperature boundary condition model using the temperature profile of the welded beads. However, each model has pros and cons in terms of calculation times and difficulties in determining welding parameters. In this paper, a new method using the moving temperature profile model is proposed to perform efficiently 3-D FE welding residual stress analysis for large structures. Comparison with existing experimental residual stress measurement data of two-pass welding pipe and SNL(Sandia National Laboratories) mock-up canister shows the accuracy and efficiency of the proposed method.

Elasto-plastic thermal stress analysis of functionally graded hyperbolic discs

  • Demir, Ersin;Callioglu, Hasan;Sayer, Metin
    • Structural Engineering and Mechanics
    • /
    • v.62 no.5
    • /
    • pp.587-593
    • /
    • 2017
  • The objective of this analytical study is to calculate the elasto-plastic stresses of Functionally Graded (FG) hyperbolic disc subjected to uniform temperature. The material properties (elastic modulus, thermal expansion coefficient and yield strength) and the geometry (thickness) of the disc are assumed to vary radially with a power law function, but Poisson's ratio does not vary. FG disc material is assumed to be non-work hardening. Radial and tangential stresses are obtained for various thickness profile, temperature and material properties. The results indicate that thickness profile and volume fractions of constituent materials play very important role on the thermal stresses of the FG hyperbolic discs. It is seen that thermal stresses in a disc with variable thickness are lower than those with constant thickness at the same temperature. As a result of this, variations in the thickness profile increase the operation temperature. Moreover, thickness variation in the discs provides a significant weight reduction. A disc with lower rigidity at the inner surface according to the outer surface should be selected to obtain almost homogenous stress distribution and to increase resistance to temperature. So, discs, which have more rigid region at the outer surface, are more useful in terms of resistance to temperature.

Numerical Analysis on Body Temperature Change with Heating Life Vest (발열구명동의 착용에 의한 인체의 체온변화에 관한 수치해석)

  • Kim, Myoung-Jun
    • Journal of the Korean Society of Marine Environment & Safety
    • /
    • v.14 no.3
    • /
    • pp.241-245
    • /
    • 2008
  • The characteristics of temperature profile around human body with heating life vest at sea were investigated in this paper. Especially, the temperature profile of human body was numerically calculated by finite difference method with Mathcad. The main parameters were seasonal mean sea water temperature, heating amount and heating duration time of heating life vest. In this paper, the boundary layer was composed by the difference matters, and the thermal conductivity was calculated with an adjacent cells using thermal resistance method. It was clarified that the body temperature was kept highly and the risk of death from hypothermia was reduced by wearing heating life vest.

  • PDF

Prediction of Laminar Flame Thickness of Ethanol-Air Pre-Mixture (에탄올-공기 예혼합기의 층류 화염두께 예측)

  • Kwon, Soon-Ik;Kim, Sang-Jin
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.28 no.11
    • /
    • pp.1417-1423
    • /
    • 2004
  • The thickness of laminar flame and preheat zone was computed from equation with burning velocity and the temperature profile, which is obtained by using premix code of Chemkin program for ethanol-air mixture. The computations were carried out under the unburned gas pressure 0.5bar-30bar and temperature of 300k-700K at 1.0. A difference flame thickness showed between temperature profile and equation with burning velocity. The ratio of flame thickness derived from the equation was about 45∼65% of the temperature profile, and the thickness of preheat zone was about 67.1% of the flame thickness. The flame thickness was decreased by increasing the pressure and temperature, but the effect of pressure is more significant than the effect of temperature on the flame thickness. The flame thickness was predicted by using the following equation. X(mm) = $X_{st}$ (T/300)$^{-0}$.65/(P)$^{-0}$.68/ (0.5bar$\leq$P$\leq$30bar, 300K$\leq$T$\leq$700K)K)

Retrieval of Thermal Tropopause Height using Temperature Profile Derived from AMSU-A of Aqua Satellite and its Application (Aqua 위성 AMSU-A 고도별 온도자료를 이용한 열적 대류권계면 고도 산출 및 활용)

  • Cho, Young-Jun;Shin, Dong-Bin;Kwon, Tae-Yong;Ha, Jong-Chul;Cho, Chun-Ho
    • Atmosphere
    • /
    • v.24 no.4
    • /
    • pp.523-532
    • /
    • 2014
  • In this study, thermal tropopause height defined from WMO (World Meteorological Organization) using temperature profile derived from Advance Microwave Sounding Unit-A (AMSU-A; hereafter named AMSU) onboard EOS (Earth Observing System) Aqua satellite is retrieved. The temperature profile of AMSU was validated by comparison with the radiosonde data observed at Osan weather station. The validation in the upper atmosphere from 500 to 100 hPa pressure level showed that correlation coefficients were in the range of 0.85~0.97 and the bias was less than 1 K with Root Mean Square Error (RMSE) of ~3 K. Thermal tropopause height was retrieved by using AMSU temperature profile. The bias and RMSE were found to be -5~ -37 hPa and 45~67 hPa, respectively. Correlation coefficients were in the range of 0.5 to 0.7. We also analyzed the change of tropopause height and temperature in middle troposphere in the extreme heavy rain event (23 October, 2003) associated with tropopause folding. As a result, the distinct descent of tropopause height and temperature decrease of ~8 K at 500 hPa altitude were observed at the hour that maximum precipitation and maximum wind speed occurred. These results were consistent with ERA (ECMWF Reanalysis)-Interim data (potential vorticity, temperature) in time and space.