• 제목/요약/키워드: h-method

검색결과 21,290건 처리시간 0.048초

Column Chromatography에 의한 바르비탈류 분리 정량법에 관한 연구 (Quantitative Determination of Barbiturates by Column Chromatographic Method)

  • 정인명;심수일;최광식;전성환;고미혜;부인향
    • Journal of Pharmaceutical Investigation
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    • 제9권4호
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    • pp.1-7
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    • 1979
  • The analytical method of phenobarbital and mephobarbital in the pharmaceutical preparation were investigated by the partition chromatographic method. The influence of 13 kinds of excipients and various kinds of ingredients such as 8 kinds of antipyretics and 5 kinds of antacids on the partition chromatographic analysis of phenobarbital and mephobarbital in the preparation were investigated. The results were not affected by materials with the exception of caffeine, aspirin and sulpyrin.

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2차원 소나돔 형상 구조물의 난류유동소음 해석 (Turbulent-induced Noise of 2-dimensional Sonar Dome Shaped Structure)

  • 최요셉;홍석윤;송지훈;권현웅;최원석;정철민
    • 한국소음진동공학회논문집
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    • 제26권1호
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    • pp.39-48
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    • 2016
  • The latest research has shown that the turbulence-induced noise is important in total characteristics of flow noise. Also, turbulence-induced noise have a significant influence for performance of sonar dome. In this paper, Flow analysis is performed on vicinity of the sonar dome model using Large Eddy Simulation method. Also, direct method that extracts perturbational sound pressure, FW-H method without turbulence-induced noise and permeable FW-H method that is able to calculate turbulence- induced noise were compared in order to show turbulence effect.

Rovibrational Energy Transitions and Coupled Chemical Reaction Modeling of H+H2 and He+H2 in DSMC

  • Kim, Jae Gang
    • International Journal of Aeronautical and Space Sciences
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    • 제16권3호
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    • pp.347-359
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    • 2015
  • A method of describing the rovibrational energy transitions and coupled chemical reactions in the direct simulation Monte Carlo (DSMC) calculations is constructed for $H(^2S)+H_2(X^1{\Sigma}_g)$ and $He(^1S)+H_2(X^1{\Sigma}_g)$. First, the state-specific total cross sections for each rovibrational states are proposed to describe the state-resolved elastic collisions. The state-resolved method is constructed to describe the rotational-vibrational-translational (RVT) energy transitions and coupled chemical reactions by these state-specific total cross sections and the rovibrational state-to-state transition cross sections of bound-bound and bound-free transitions. The RVT energy transitions and coupled chemical reactions are calculated by the state-resolved method in various heat bath conditions without relying on a macroscopic properties and phenomenological models of the DSMC. In nonequilibrium heat bath calculations, the state-resolved method are validated with those of the master equation calculations and the existing shock-tube experimental data. In bound-free transitions, the parameters of the existing chemical reaction models of the DSMC are proposed through the calibrations in the thermochemical nonequilibrium conditions. When the bound-free transition component of the state-resolved method is replaced by the existing chemical reaction models, the same agreement can be obtained except total collision energy model.

모델 예측 제어 기반 Cascaded H-bridge 컨버터의 균일한 손실, 스위칭 주파수, 전력 분배를 위한 알고리즘 (An Algorithm for Even Distribution of Loss, Switching Frequency, Power of Model Predictive Control Based Cascaded H-bridge Multilevel Converter)

  • 김이김;곽상신
    • 전력전자학회논문지
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    • 제20권5호
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    • pp.448-455
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    • 2015
  • A model predictive control (MPC) method without individual PWM has been recently researched to simplify and improve the control flexibility of a multilevel inverter. However, the input power of each H-bridge cell and the switching frequency of switching devices are unbalanced because of the use of a restricted switching state in the MPC method. This paper proposes a control method for balancing the switching patterns and cell power supplied from each isolated dc source of a cascaded H-bridge inverter. The supplied dc power from isolated dc sources of each H-bridge cells is balanced with the proposed cell balancing method. In addition, the switching frequency of each switching device of the CHB inverter becomes equal. A simulation and experimental results are presented with nine-level and five-level three-phase CHB inverter to validate the proposed balancing method.

유전 알고리즘을 이용한 모델 추종형 최적 다변수 보일러-터빈 H_\infty제어 시스템의 세계 (A Design of Model Following Optimal Multivariable BOiler-Turbine H_\infty Control System using Genetic Algorithm)

  • 황현준;김동완;박준호;황창선
    • 대한전기학회논문지:전력기술부문A
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    • 제48권2호
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    • pp.127-135
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    • 1999
  • Multivarialbe Boiler-Turbine H_\infty Control System Genetic Algorithm Weighting Functions $W_1$(s), $W_2$(s), and design parameter $\gamma$ that are given by Glover-Doyle algorithm, to optimally follow the output of reference model. The first method to do this is that the gains of weighting functions $W_1$(s), $W_2$(s), and design parameter are optimized simultaneously by genetic algorithm with the tournament method that can search more diversely, in the search domain which guarantees the robust stability of system. And the second method is that not only by genetic algorithm with the roulette-wheel method that can search more fast, in that search domain. The boiler-turbine H_\infty control system designed by theabove second method has not only the robust stability to a modeling error but also the the better command tracking preformance than those of the H_\infty control system designed by trial-and-error method and the above first method. Also, this boiler-turbine H_\infty control system has the better performance than that of the LQG/LTR contro lsystem. The effectiveness of this boiler-turbineH_\infty control system is verified by computer simulation.

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Passaging Method for Expansion of Undifferentiated Human Embryonic Stem Cells by Pipetting Technique

  • Lee, Sung-Geum;Moon, Sung-Hwan;Lee, Soo-Hong;Lee, Hey-Jin;Kim, Jae-Hwan;Chung, Hyung-Min
    • Reproductive and Developmental Biology
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    • 제30권4호
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    • pp.287-291
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    • 2006
  • We have developed a new passaging technique for the expansion of human embryonic stem cells (hESCs) that involves simply pipetting portions of hESCs acquired from colonies, reducing the laborious and time-consuming steps in the expansion of hESCs. Compared to general mechanical methods of passaging, our pipetting method allowed hESCs colonies to be broken into small fragments, which showed significantly higher attachment rates onto feeder cell layers. This technique produced three times the number of hESCs colonies than conventional mechanical methods. In addition, this pipetting method allowed us to distinguish differentiated hESCs from undifferentiated hESCs during hESCs colony pipetting. The hESCs cultured by pipetting method displayed normal human chromosomes for over 60 passages. According to RT-PCR and immunohistochemical analysis, the hESCs successfully maintained their undifferentiated state and pluripotency which was also confirmed by teratoma formation in viva Therefore, the pipetting method described in this study is a useful tool to efficiently and quickly expand hESCs on a large scale without enzyme treatment.

SIMD기법에 의한 H.263 코덱의 PC기반 실시간 구현 (PC-Based Realtime Implementation of H.263 CODEC Using SIMD Method)

  • 하교동;남수영;김남철
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2001년도 제14회 신호처리 합동 학술대회 논문집
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    • pp.947-950
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    • 2001
  • This paper implements H.263 codec using SIMD(single instruction multiple data) method in real time based on PC. This system uses INS algorithm previously proposed by the authors as motion estimation module. SIMD method is used in DCT, IDCT, quantization, motion estimation, and display module. The developed algorithms are implemented using TMN5. Using the above algorithm, H.263 Codec can communicate more than 15 frames/sec in CIF resolution on a Pentium-IV 1.7GHz computer.

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