• 제목/요약/키워드: Fast Green

검색결과 256건 처리시간 0.03초

고속원자충격질량분석에 의한 녹차성분 검색 (Diagnostic FAB-MS Spectra of Green Tea Components)

  • 문동철;이정희;이용문
    • 약학회지
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    • 제36권3호
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    • pp.205-211
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    • 1992
  • A simple dignostic method using Fast Atom Bombardment mass spectrometry was applied to the characterization of green tea flavonols from the eluates of Sepahadex LH-20 column chromatography. From the ethyl acetate extracts, crude mixture of flavonol fraction(Fr.$1{\sim}4$) were separated by the stepwise gradient elution with 30, 45, and 60% aqueous acetone. Procyanidine B analogues were found to be typical constituents of Fr. 1. Main components of Fr. 2 were catechins and gallo-catechins. Fr. 3 contained mainly ester type compounds, catechin-gallates, gallocatechin-gallates with their analogues. Fr. 4 was contaminated with some phthalate esters.

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지하물체 탐지를 위한 FMM 기반의 효율적인 수치 해석 연구 (Numerical Experiments using Efficient FMM for the EM Scattering by Underground Object)

  • 김승환;안창회
    • 전기학회논문지
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    • 제58권9호
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    • pp.1790-1795
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    • 2009
  • For GPR(Ground Penetrating Radar) applications, an accurate analysis of the scattered field is necessary to identify the unknown target. Dyadic Green's function of the multilayered medium is developed and applied to analysis of the underground conducting object. We used method of moment(MOM) with dyadic Green's function, and Discrete Complex Image Method(DCIM). To reduce the computational complexity, fast multipole method is introduced and we showed the accuracy of the method comparing with the conventional method of moment. For investigating the underground conducting target, several numerical experiments were accomplished using this method.

An IE-FFT Algorithm to Analyze PEC Objects for MFIE Formulation

  • Seo, Seung Mo
    • Journal of electromagnetic engineering and science
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    • 제19권1호
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    • pp.6-12
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    • 2019
  • An IE-FFT algorithm is implemented and applied to the electromagnetic (EM) solution of perfect electric conducting (PEC) scattering problems. The solution of the method of moments (MoM), based on the magnetic field integral equation (MFIE), is obtained for PEC objects with closed surfaces. The IE-FFT algorithm uses a uniform Cartesian grid to apply a global fast Fourier transform (FFT), which leads to significantly reduce memory requirement and speed up CPU with an iterative solver. The IE-FFT algorithm utilizes two discretizations, one for the unknown induced surface current on the planar triangular patches of 3D arbitrary geometries and the other on a uniform Cartesian grid for interpolating the free-space Green's function. The uniform interpolation of the Green's functions allows for a global FFT for far-field interaction terms, and the near-field interaction terms should be adequately corrected. A 3D block-Toeplitz structure for the Lagrangian interpolation of the Green's function is proposed. The MFIE formulation with the IE-FFT algorithm, without the help of a preconditioner, is converged in certain iterations with a generalized minimal residual (GMRES) method. The complexity of the IE-FFT is found to be approximately $O(N^{1.5})$and $O(N^{1.5}logN)$ for memory requirements and CPU time, respectively.

Ultra-Fast L2-CL Code Acquisition for a Dual Band GPS Receiver

  • Kim, Binhee;Kong, Seung-Hyun
    • Journal of Positioning, Navigation, and Timing
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    • 제4권4호
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    • pp.151-160
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    • 2015
  • GPS L2C signal is a recently added civil signal to L2 frequency and is constructed by time division multiplexing of civil moderate (L2-CM) and civil long (L2-CL) code signals. While the L2-CM code is 20 ms-periodic and modulates satellite navigation message, the L2-CL code is 1.5s-periodic with 767,250 chips long code sequence and carries no data. Therefore, the L2-CL code signal allows receivers to perform a very long coherent integration. However, due to the length of the L2-CL code, the acquisition of the L2-CL code signal may take too long or require too much hardware resources. In this paper, we propose a three-step ultra-fast L2-CL code acquisition (TSCLA) technique for dual band GPS receivers. In the proposed TSCLA technique, a dual band GPS receiver sequentially acquires the coarse/acquisition (C/A) code signal at L1 frequency, the L2-CM code signal, and the L2-CL code signal to minimize mean acquisition time (MAT). The theoretical performance analysis and numerous Monte Carlo simulations show the significant advantage of the proposed TSCLA technique over conventional techniques introduced in the literature.

Low Computational FFT-based Fine Acquisition Technique for BOC Signals

  • Kim, Jeong-Hoon;Kim, Binhee;Kong, Seung-Hyun
    • Journal of Positioning, Navigation, and Timing
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    • 제11권1호
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    • pp.11-21
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    • 2022
  • Fast Fourier transform (FFT)-based parallel acquisition techniques with reduced computational complexity have been widely used for the acquisition of binary phase shift keying (BPSK) global positioning system (GPS) signals. In this paper, we propose a low computational FFT-based fine acquisition technique, for binary offset carrier (BOC) modulated BPSK signals, that depending on the subcarrier-to-code chip rate ratio (SCR) selectively utilizes the computationally efficient frequency-domain realization of the BPSK-like technique and two-dimensional compressed correlator (BOC-TDCC) technique in the first stage in order to achieve a fast coarse acquisition and accomplishes a fine acquisition in the second stage. It is analyzed and demonstrated that the proposed technique requires much smaller mean fine acquisition computation (MFAC) than the conventional FFT-based BOC acquisition techniques. The proposed technique is one of the first techniques that achieves a fast FFT-based fine acquisition of BOC signals with a slight loss of detection probability. Therefore, the proposed technique is beneficial for the receivers to make a quick position fix when there are plenty of strong (i.e., line-of-sight) GNSS satellites to be searched.

FMM에 의한 프랙탈 안테나 고속 해석 (Fast Analysis of Fractal Antenna by Using FMM)

  • 김요식;이광재;김건우;오경현;이택경;이재욱
    • 한국전자파학회논문지
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    • 제19권2호
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    • pp.121-129
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    • 2008
  • 본 논문에서는 FMM(Fast Multipole Method)을 적용하여 평면형 다층 구조인 마이크로스트립 프랙탈 안테나 구조에 대한 고속 해석을 구현하였다. 우선 FMM 알고리즘에 이용되는 적분식인 MPIE(Mixed Potential Integral Equation)을 풀기 위해서 실수축 적 분 방법(RAIM: Real-Axis Integration Method)으로부터 정확한 공간 영역 그린함수를 구한다. 구해진 그린함수를 MoM(Method of Moment)을 이용하여 계산할 경우, 연산과 메모리 요구량 $O(N^2)$이 소요되는데, 이를 거대 구조의 해석에 대해 적용할 때나 높은 정확성을 위한 셀(미지수 N) 수의 증가하는 경우 계산량이 기하급수적으로 증가하여 구조 해석에 문제가 된다. FMM은 이와 같은 연산과 메모리 요구량의 문제점을 해결하기 위하여 개발되었다. FMM은 그린함수의 가법 정리(addition theorem)를 이용하여 행렬-벡터 곱의 복잡성을 줄여 연산과 메모리 요구량을 $O(N^{1.5})$으로 줄인다. 시어핀스키(Sierpinski) 프랙탈 안테나의 구조에 대해 MoM과 FMM를 적용, 상용 툴과 계산 결과의 정확성, 계산 시 메모리 크기, 해석 시간 등을 비교하여 효율성을 보여주었다.

Rapd Analysis of Trichoderma Isolates for Superior Selection for Biopesticide Preparation

  • Parvin, Shahnaj;Islam, Abu Taher Mohammad Shafiqul;Siddiqua, Mahbuba Khatoon;Uddin, Mohammad Nazim;Meah, Mohammad Bahadur
    • 한국작물학회지
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    • 제56권1호
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    • pp.35-43
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    • 2011
  • Thirty five isolates of Trichoderma species collected from seven different locations of Bangladesh were studied for morphological characters and molecular variation. Mycelial diameters of the isolates varied from 8.28 cm to 9.00 cm. Based on colony colour, isolates were grouped into five such as dark green, green, light green, yellowish green and whitish green. Maximum isolates were green and light green. On the basis of growth habit and colony consistency, the isolates were categorized into three groups, in which most species had fast growth and were compact in appearance. PCR-based Random Amplified Polymorphic DNA (RAPD) technique employing 3 decamer primers produced 36 scorable bands of which all (100%) were polymorphic. The co-efficient of gene differentiation (Gst) was 1.0000 reflecting the existence of high level of genetic diversity among the isolates. The Unweighted Pair Group Method of Arithmetic Means (UPGMA) dendrogram constructed from Nei's (1972) genetic distance produced 2 main clusters (13 isolates in cluster 1 and 22 isolates in cluster 2). The result indicating their genetic diversity has opened new possibility of using the most efficient and more isolates of Trichoderma in the preparation of biopesticide and decomposition of municipality waste.

LTCC 슬러리 및 그린시트의 물성 변화에 미치는 혼합용매 조성의 영향 (Effect of Solvent Mixture on the Properties of LTCC Slurry and Green Sheets)

  • 조범준;박은태
    • 한국재료학회지
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    • 제16권9호
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    • pp.533-537
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    • 2006
  • The effects of binary solvent mixtures with various ratios of toluene and ethanol on the properties of slurries and green sheets were investigated. Viscosity of slurry was changed by varying the ratio of solvent mixture which affected the solubility of binder. The relative solvency behavior of a solvent mixture could be predicted with the Hildebrand solubility parameter(${\delta}$) and hydrogen bonding index( ${\gamma}$). The minimum viscosity, the best dispersion of binder, was reached at the composition of toluene:ethanol=4:6, which corresponded to our forecast. The mechanical properties of green sheets related to evaporation of solvents were influenced by the composition of the solvent mixture. At the azeotrope the skin was formed on a drying cast during the drying process because of fast evaporation. At a range of concentrations over 50wt% toluene, green sheets could not be fully dried at low temperature due to excessive toluene. The mechanical properties of green sheets were excellent at the azeotrope-like composition of toluene:ethanol=4:6 which has a little excess of toluene over the azeotrope.

LEED v3(2009)에서의 친환경 단지 개발에 관한 연구 - LEED for Neighborhood Development를 중심으로 (A Study on LEED v3(2009) Sustainable Neighborhood Development - Focused on LEED for Neighborhood Development)

  • 안동준
    • KIEAE Journal
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    • 제11권3호
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    • pp.11-18
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    • 2011
  • Sustainability became the keyword of our society worldwide, and it is undoubtful that buildings are mainly responsible for green house gas emission and energy consumption. Responding to current needs, US Green Building Council has launched the first LEED rating system in 1998. Since then, LEED has been evolved and it has multiple sub-system categorized by project types. This study aims to analyze characteristics of sustainable neighborhood development and to suggest methodology for establishing certification system in Korea. First, LEED-ND 2009(LEED for Neighborhood Development) was addressed with certified projects by US Green Building Council. After that, LEED-NC 2009(LEED for New Construction) was compared with green building certification criteria in Korea to find out unforeseen aspects by each system, in terms of sustainable neighborhood development. As a result of this study, sustainable neighborhood development requires a transition of architects' responsibility beyond building design. Building technology has been advanced at extremely fast pace, however, applying techniques to individual architecture would not make our town sustainable. This study provided basic resources to understand that creating sustainable neighborhood is social phenomenon and more studies should be undertaken to establish Green Neighborhood Certification Criteria in Korea.