• Title/Summary/Keyword: Mixed-spectrum

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Design of a Mixed-Spectrum Reactor With Improved Proliferation Resistance for Long-Lived Applications

  • Abou-Jaoude, Abdalla;Erickson, Anna;Stauff, Nicolas
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.16 no.3
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    • pp.359-367
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    • 2018
  • Long-lived Small Modular Reactors are being promoted as an innovative way of catering to emerging markets and isolated regions. They can be operated continuously for decades without requiring additional fuel. A novel configuration of long-lived reactor core employs a mixed neutron spectrum, providing an improvement in nonproliferation metrics and in safety characteristics. Starting with a base sodium reactor design, moderating material is inserted in outer core assemblies to modify the fast spectrum. The assemblies are shuffled once during core lifetime to ensure that every fuel rod is exposed to the thermalized spectrum. The Mixed Spectrum Reactor is able to maintain a core lifetime over two decades while ensuring the plutonium it breeds is below the weapon-grade limit at the fuel discharge. The main drawbacks of the design are higher front-end fuel cycle costs and a 58% increase in core volume, although it is alleviated to some extent by a 48% higher power output.

Parametric Modelling of Coupled System (커플시스템의 파라메트릭 모델링)

  • Yoon, Moon-Chul;Kim, Jong-Do;Kim, Byung-Tak
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.5 no.3
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    • pp.43-50
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    • 2006
  • In this successive study, the analytical realization of coupled system was introduced using the times series identification and spectrum analysis, which was compared with conventional FFT spectrum. Also, the numerical responses of second order system, which is coupled, were solved using the numerical calculation of Runge-Kutta Gill method. After numerical analysis, the displacement, velocity and acceleration were acquired. Among them, the response of displacement was used for the analysis of time series spectrum. Among several time series, the ARMAX algorithm was proved to be appropriate for the spectrum analysis of the coupled system. Using the separated response of 1st and 2nd mode, the mode was calculated separately. And the responses of mixed modes were also analyzed for calculation of the mixed modes in the coupled system.

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Laver Farm Feature Extraction From Landsat ETM+ Using Independent Component Analysis

  • Han J. G.;Yeon Y. K.;Chi K. H.;Hwang J. H.
    • Proceedings of the KSRS Conference
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    • 2004.10a
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    • pp.359-362
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    • 2004
  • In multi-dimensional image, ICA-based feature extraction algorithm, which is proposed in this paper, is for the purpose of detecting target feature about pixel assumed as a linear mixed spectrum sphere, which is consisted of each different type of material object (target feature and background feature) in spectrum sphere of reflectance of each pixel. Landsat ETM+ satellite image is consisted of multi-dimensional data structure and, there is target feature, which is purposed to extract and various background image is mixed. In this paper, in order to eliminate background features (tidal flat, seawater and etc) around target feature (laver farm) effectively, pixel spectrum sphere of target feature is projected onto the orthogonal spectrum sphere of background feature. The rest amount of spectrum sphere of target feature in the pixel can be presumed to remove spectrum sphere of background feature. In order to make sure the excellence of feature extraction method based on ICA, which is proposed in this paper, laver farm feature extraction from Landsat ETM+ satellite image is applied. Also, In the side of feature extraction accuracy and the noise level, which is still remaining not to remove after feature extraction, we have conducted a comparing test with traditionally most popular method, maximum-likelihood. As a consequence, the proposed method from this paper can effectively eliminate background features around mixed spectrum sphere to extract target feature. So, we found that it had excellent detection efficiency.

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Pushover Analysis for Nonlinear Seismic Response of Reinforced Concrete Mixed Building Structures (철근콘크리트 복합구조물의 비선형 지진응답산정을 위한 Pushover해석)

  • Kang Pyeong-Doo;Jun Dae-Han;Kim Jae-Ung
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.631-638
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    • 2006
  • This paper considers the nonlinear direct spectrum method to estimate seismic performance of mixed building structures without iterative computations, given dynamic property $T_1$ from stiffness skeleton curve and nonlinear pseudo acceleration $A_{1y}$ and/or ductility ratio $\mu$ from response spectrum. Nonlinear response history analysis has been performed and analysed with various earthquakes for evaluation of correctness and confidence of nonlinear direct spectrum method.

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Parametric Modelling of Uncoupled System (언커플시스템의 파라메트릭 모델링)

  • Yoon, Moon-Chul;Kim, Jong-Do;Kim, Kwang-Heui
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.5 no.3
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    • pp.36-42
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    • 2006
  • The analytical realization of uncoupled system was introduced in this study using times series and its spectrum analysis. The ARMAX spectra of time series methods were compared with the conventional FFT spectrum. Also, the response of second order system uncoupled was solved using the Runge-Kutta Gill method. In this numerical analysis, the displacement, velocity and acceleration were calculated. The displacement response among them was used for the power spectrum analysis. The ARMAX algorithm in time series was proved to be appropriate for the mode estimation and spectrum analysis. Using the separate response of first and second mode, each modes were calculated separately and the response of mixed modes was also analyzed for the mode estimation using several time series methods.

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Identification and Determination of Oil Pollutants Based on 3-D Fluorescence Spectrum Combined with Self-weighted Alternating Trilinear Decomposition Algorithm

  • Cheng, Pengfei;Wang, Yutian;Chen, Zhikun;Yang, Zhe
    • Journal of the Optical Society of Korea
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    • v.20 no.1
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    • pp.204-211
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    • 2016
  • Oil pollution seriously endangers the biological environment and human health. Due to the diversity of oils and the complexity of oil composition, it is of great significance to identify the oil contaminants. The 3-D fluorescence spectrum combined with a second order correction algorithm was adopted to measure an oil mixture with overlapped fluorescence spectra. The self-weighted alternating trilinear decomposition (SWATLD) is a kind of second order correction, which has developed rapidly in recent years. Micellar solutions of #0 diesel, #93 gasoline and ordinary kerosene in different concentrations were made up. The 3-D fluorescence spectra of the mixed oil solutions were measured by a FLS920 fluorescence spectrometer. The SWATLD algorithm was applied to decompose the spectrum data. The predict concentration and recovery rate obtained by the experiment show that the SWATLD algorithm has advantages of insensitivity to component number and high resolution for mixed oils.

A Case of Two SRY Genes in a Tuner's Syndrome Feature (터너증후군 의심환자에서 2개의 SRY 유전자 발현 1예)

  • Park, Sang-Muk;Kim, Yoon-Sik
    • Korean Journal of Clinical Laboratory Science
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    • v.42 no.3
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    • pp.111-115
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    • 2010
  • A 15-year-old female with primary amenorrhea and Tuner's syndrome feature was referred for a chromosome analysis. The karyotype of the patient was 45,X/46,X,der(Y) mosaicism under initial GTG-banding analysis. Fluorescence in situ hybridization (FISH) analysis with probe for CEP X probes and SRY probe (Vysis, Inc. Downers Grove, IL 60515, USA) was carried out. This probe is direct labeled with SpectrumOrange (SRY, Yp11.3) and is available as a single probe or mixed with the CEP X SpectrumGreen probe. SRY SpectrumOrange/CEP X SpectrumGreen hybridized to a specimen obtained from an two isodicentric Y chromosomes. The karyotype of the patient was ish Xcen(DXZ1x1)/Xcen(DXZ1x1), Yp11.3(SRYx2) by using FISH. This karyotype was considered a variant of Tuner syndrome with mixed gonadal dysgenesis (MGD), male pseudohermaphroitism (MPH) and apparently normal male.

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Fabrication of Mixed and Patterned Type of Remote Phosphors by Screen Printing Process and their Optical Properties

  • Kim, Byung-Ho;Hwang, Jonghee;Lee, Young Jin;Kim, Jin-Ho;Jeon, Dae-Woo;Lee, Mi Jai
    • Journal of the Korean Ceramic Society
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    • v.53 no.4
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    • pp.381-385
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    • 2016
  • Recently, white LEDs, especially, warm white LEDs have been intensively investigated due to outstanding optical properties, long term stability and low power consumption. In this study, mixed type and patterned type of remote phosphors were prepared by screen printing process employing green and red phosphor. Each type of remote phosphor exhibited distinctive photoluminescence spectrum. For example, the mixed type of remote phosphor exhibited unique spectrum, while the patterned type showed expectable spectrum depending on the concentration of phosphors. This indicates that a small amount of red phosphor dramatically reduced the green photoluminescence in the case of mixed-type remote phosphor, whereas the effect was negligible in the patterned-type remote phosphor. The possibility of undesirable chemical reaction was further investigated by using scanning electron microscopy and X-ray diffraction.

The Application of a Nonlinear Direct Spectrum Method for Mixed Building Structure (복합구조물에 대한 비선형 직접스펙트럼법의 적용)

  • 강병두;박진화;전대한;김재웅
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2002.09a
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    • pp.258-265
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    • 2002
  • Most structures are expected deform nonlinear and inelastic behavior when subjected to strong ground motion. Nonlinear time history analysis(NTHA) is the most rigorous procedure to compute seismic performance in the various inelastic analysis methods. But nonlinear analysis procedures necessitate more reliable and practical tools for predicting seismic behavior of structures. Some building codes propose the capacity spectrum method. This method is the concept of an equivalent linear system, wherein a linear system having reduced stiffness and increased damping is used to estimate the response of the nonlinear system. This procedure are conceptually simple, but the iterative procedure is time-consuming and may sometimes lead to no solution or multiple solutions. This paper presents a nonlinear direct spectrum method(NDSM) to evaluate seismic performance of structures, without iterative computations, given by the structural initial elastic period and yield strength from the pushover analysis, especially for mixed building structure.

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Validity of Ocean Wave Spectrum Using Rayleigh Probability Density Function

  • Choi, Young Myung;Yang, Young Jun;Kwon, Sun Hong
    • International Journal of Ocean System Engineering
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    • v.2 no.4
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    • pp.250-258
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    • 2012
  • The distribution of wave heights is assumed to be a Rayleigh distribution, based on the assumption of a narrow band and Gaussian distribution of wave elevation. The present study was started with doubts about the narrow band assumption. We selected the wave spectra widely used to simulate irregular random waves. The wave spectra used in this study included the Pierson-Moskowitz spectrum, Bretschneider-Mitsuyasu spectrum, and JONSWAP spectrum. The directionality of the waves was considered. The cosine 2-l type directional spreading function and mixed form of the half-cosine 2-s type with Mitsuyasu type directional spreading are considered here to investigate the effects of a directional spreading function on random waves. The simulated wave height distribution is compared with a Rayleigh distribution.