• 제목/요약/키워드: Stabilized method

검색결과 750건 처리시간 0.03초

Novel Coatable Polarizer Based on Polymer-Stabilized Lyotropic Chromonic Liquid Crystals

  • Bae, Yun-Ju;Jeong, Kwang-Un;Shin, Seung-Han;Lee, Myong-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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    • pp.517-519
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    • 2009
  • We fabricated thin film polarizer by coating lyotropic chromonic liquid crystals (LCLCs) dissolved in anionic monomer solution. Compared to water-based technique, the new method provided many advantages such as excellent coatability, good adhesion to various substrates, and superb surface hardness.

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Triethanolamine 착체졸을 이용한 PZT 섬유의 제조 (Preparation of PZT Fibers Using Triethanolamine Complexed Sol)

  • 박용일;이해욱;최용수;이종혁;김승현;김창은
    • 한국세라믹학회지
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    • 제33권7호
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    • pp.755-760
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    • 1996
  • Sol-gel processing was used to prepare PZT fibers. Titanium isopropoxide Zirconium n-butoxide and lead acetate trihydrate were used as starting materials and TEA(triethanolamine) was added to form stabilized Pb-Ti-Zr complex alkoxide, Effects of catalysts and various solvents on the state of precursor sol gelation reaction fiber spinnability pyrolysis and crystallization were also investiated.

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Evaluating the ANSS and ATS Values of the Multivariate EWMA Control Charts with Markov Chain Method

  • Chang, Duk-Joon
    • 통합자연과학논문집
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    • 제7권3호
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    • pp.200-207
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    • 2014
  • Average number of samples to signal (ANSS) and average time to signal (ATS) are the most widely used criterion for comparing the efficiencies of the quality control charts. In this study the method of evaluating ANSS and ATS values of the multivariate exponentially weighted moving average (EWMA) control charts with Markov chain approach was presented when the production process is in control state or out of control state. Through numerical results, it is found that when the number of transient state r is less than 50, the calculated ANSS and ATS values are unstable; and ATS(r) tends to be stabilized when r is greater than 100; in addition, when the properties of multivariate EWMA control chart is evaluated using Markov chain method, the number of transient state r requires bigger values when the smoothing constatnt ${\lambda}$ becomes smaller.

다꾸치법에 의한 무섬유 세라믹 브레이크 마찰재의 제조변수에 대한 고찰 (Investigation of Manufacturing Parameters for Non-fibrous Ceramic Brake Pads using Taguchi Method)

  • 여정구;최성철
    • 한국재료학회지
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    • 제14권1호
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    • pp.59-66
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    • 2004
  • In the present study, ceramic brake pads without fiber phases were manufactured by the low temperature heat treatment below$ 700 ^{\circ}C$. The manufacturing parameters of ceramic brake pads and those levels were investigated by the analysis results of signal-to-noise ratios, ANOVA based upon the Taguchi method. The ceramic brake pads prepared in the Mg experiment had a friction coefficient of 0.30~0.55 very close to the target coefficient (0.35~0.45) of commercial brake pads utilized in the automobiles. The frictional properties of ceramic brake pads could be stabilized with the adjustment of amounts of lubricating additives. The optimum preparation conditions as well as batch formulations for the fabrication of non-fibrous ceramic brake pads were finally determined using Taguchi method in this study.

A natural frequency sensitivity-based stabilization in spectral stochastic finite element method for frequency response analysis

  • Lee, Gil-Yong;Jin, Seung-Seop;Park, Yong-Hwa
    • Structural Engineering and Mechanics
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    • 제75권3호
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    • pp.311-325
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    • 2020
  • In applying the spectral stochastic finite element methods to the frequency response analysis, the conventional methods are known to give unstable and inaccurate results near the natural frequencies. To address this issue, a new sensitivity based stabilized formulation for stochastic frequency response analysis is proposed in this paper. The main difference over the conventional spectral methods is that the polynomials of random variables are applied to both numerator and denominator in approximating the harmonic response solution. In order to reflect the resonance behavior of the structure, the denominator polynomials is constructed by utilizing the natural frequency sensitivity and the random mode superposition. The numerator is approximated by applying a polynomial chaos expansion, and its coefficients are obtained through the Galerkin or the spectral projection method. Through various numerical studies, it is seen that the proposed method improves accuracy, especially in the vicinities of structural natural frequencies compared to conventional spectral methods.

Monopulse Tracking Performance of a Satcom Antenna on a Moving Platform

  • Cho, Gyuhan;Kim, Gwang Tae
    • Journal of electromagnetic engineering and science
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    • 제17권3호
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    • pp.120-125
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    • 2017
  • A satellite communication (Satcom) antenna mounted on a moving platform provides a controlled heading that enables a geosynchronous satellite to communicate with the ground. A monopulse tracking method is effective for antenna control on a vehicle when it vibrates severely. However, this method has unexpected obstacles and its control performance is insufficient. To improve its control performance, the control command and monopulse error, the signal delay, and the radome effect are evaluated through tests. The authors then propose a method to transform the antenna error from 3D coordinates to 2D antenna coordinates. As a result, the antenna control performance is improved. As indicated in this study, examining antenna systems using the monopulse method on moving platforms is possible by understanding the antenna test process.

계층적 반복과 수정 잔여치법에 의한 비압축성 유동 계산 (An Incompressible Flow Computation by a Hierarchical Iterative and a Modified Residual Method)

  • 김진환
    • 한국전산유체공학회지
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    • 제9권3호
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    • pp.57-65
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    • 2004
  • The incompressible Navier-Stokes equations in two dimensions are stabilized by a modified residual method, and then discretized by hierarchical elements. The stabilization is necessary to escape from the Ladyzhenskaya-Babuska-Brezzi(LBB) constraint and hence to achieve an equal order formulation. To expedite a standard iterative method such as the conjugate gradient squared(CGS) method, a preconditioning technique called the Hierarchical Iterative Procedure(HIP) has been applied. In this paper, we increased the order of interpolation within an element up to cubic. The hierarchical elements have been used to achieve a higher order accuracy in fluid flow analyses, but a proper efficient iterative procedure for higher order finite element formulation has not been available so far The numerical results by the present HIP for the lid driven cavity flow and others showed the present procedure to be stable, very efficient and useful in flow analyses in conjunction with hierarchical elements.

적응성 선향저감적분법에 의한 요소의 안정성 향상과 강소성 유한요소해석에의 적용 (Improvement of Element Stability using Adaptive Directional Reduced Integration and its Application to Rigid-Plastic Finite Element Method)

  • Park, K.;Lee, Y.K.;Yang, D.Y.
    • 한국정밀공학회지
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    • 제12권3호
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    • pp.32-41
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    • 1995
  • In the analysis of metal forming processes by the finite element method, there are many numerical instabilities such as element locking, hourglass mode and shear locking. These instabilities may have a bad effect upon accuracy and convergence. The present work is concerned with improvement of stability and efficiency in two-dimensional rigid-plastic finite element method using various type of elemenmts and numerical intergration schemes. As metal forming examples, upsetting and backward extrusion are taken for comparison among the methods: various element types and numerical integration schemes. Comparison is made in terms of stability and efficiency in element behavior and computational efficiency and a new scheme of adaptive directional reduced integration is introduced. As a result, the finite element computation has been stabilized from the viewpoint of computational time, convergency, and numerical instability.

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비정밀접근시 CFIT사고 방지를 위한 일정강하율 접근방식에 관한 연구 (A Study on the Approach Methods with a Constant Vertical Speed for Diminution of CFIT Accidents in Non-Precision Approach)

  • 송병흠;신현삼;문경배
    • 한국항공운항학회지
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    • 제13권4호
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    • pp.43-57
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    • 2005
  • Traditionally aircraft had descended in steps to level at the MDA(Minimum Descent Altitude) during the conduct of non-precision approach. This "de-stabilized" method of flying an instrument approach procedure is considered as a major contributing factor in CFIT(Controlled Flight Into Terrain) accident and increasing pilot workload. In the effort to reduce CFIT accident and pilot workload, VNAV(Vertical Navigation) Approach has been suggested as means to manage the vertical component of non-precision approach procedure.[1] But In the actual circumstances in Korea, VNAV has not been using to reduce them because of many restriction facts and no published VNAV chart in particular airport. Therefore we are suggesting Constant Vertical Speed Approach Method, which is required few restriction facts, and the pilots who are using this method will experience a similar method like a Glideslope during proceeding non-precision approach. Consequently, We are expecting to reduce CFIT accidents and pilot workload.

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