• 제목/요약/키워드: Control-Volume Analysis

검색결과 932건 처리시간 0.027초

한약 복용이 산후 유즙분비에 미치는 효과에 대한 체계적 문헌고찰 (A Systematic Review and Meta Analysis of Randomized Controlled Trials of the Clinical Effect on Taking a Herbal Medicine on Postpartum Lactation)

  • 이혜정;이수정;황덕상;이창훈;장준복;이진무
    • 대한한방부인과학회지
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    • 제34권3호
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    • pp.137-156
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    • 2021
  • Objectives: The purpose of this study is to assess the effect of taking herbal medicine for the postpartum lactation. Methods: We searched 9 databases for recent three years, that contained four english, two chinese, one japanese and two korean database from September 17, 2016 to December 31, 2020. Randomized controlled trials (RCTs) were eligible. Measurement of outcome included total curative effective rate, volume of lactation, volume of milk supplement, and serum prolactin concentration. The risk of bias was assessed by two independent authors using the Cochrane risk of bias tool. Results: Total 725 of studies was screened, 11 RCTs were finally selected. Number of participants per study ranged from 60 to 257. The treatment group of taking a herbal medicine is effective for improving total curative effective rate, volume of lactation, volume of milk supplement, and serum prolactin concentration compared with control group. Because most of the studies had considerable heterogeneity in terms of type of intervention and comparison for outcome measurement, meta analysis for quantitative analysis was impossible. Conclusions: This studies showed that taking a herbal medicine is effective on increasing volume of lactation and speeding up the start of the first breastfeeding. However, included studies suffered from incomplete reporting, high or unclear risk of bias and substantial heterogeneity between studies. In the Future, further high-quality RCTs are needed to prove effectiveness of herbal medicine for breastfeeding and reduce the risk of bias.

제어체적법에 의한 Ar 아크 플라즈마의 특성 계산 (Numerical calculations of characteristics of Argon arc plasma using the control volume method)

  • 김외동;고광철;강형부
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1995년도 하계학술대회 논문집 C
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    • pp.1404-1406
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    • 1995
  • In this paper, argon gas was used for numerical analysis of an arc in a cutting plasma torch driven by constant current. We established nozzle-constricting type torch domain and calculated steady state characteristics of argon arc plasma using the control volume method(CVM). For simplicity, we assumed that the flow field is laminar and the local thermodynamic equilibrium(LTE) prevails in all domain regions. We also neglected cathode-fall and anode-fall effects. Considering magnetic pinch effect and viscosity effect, we solved the momentum equation. Voltage drop in the arc column due to input current was calculated from the temperature field obtained by the energy balance equation.

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섭동법을 이용한 공기윤활 슬라이더 베어링의 동특성 해석 (An Analysis of Dynamic Characteristics of Air-Lubricated Slider Bearing by Using Perturbation Method)

  • 강태식;최동훈;정태건
    • 대한기계학회논문집A
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    • 제24권6호
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    • pp.1520-1528
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    • 2000
  • This study presents a method for determining bearing stiffness and damping coefficients of air-lubricated slider bearing, and shows influences of air-bearing surface geometry(recess depth, crown an d pivot location) on flying attitude and dynamic characteristics. To derive the dynamic lubrication equation, the perturbation method is applied to the generalized lubrication equation which based on linearized Boltzmann equation. The generalized lubrication equation and the dynamic lubrication equation are converted to a control volume formulation, and then, the static and dynamic pressure distributions are calculated by finite difference method. The recess depth and crown of the slider show significantly influence on flying attitude and dynamic characteristics comparing with those of pivot location.

Analysis and Design of Whole-Head Magnetic Brain Stimulators: A Simulation Study

  • Lee, Chany;Im, Chang-Hwan;Jung, Hyun-Kyo
    • International Journal of Control, Automation, and Systems
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    • 제5권3호
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    • pp.337-342
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    • 2007
  • This paper proposes a helmet-type whole-head brain stimulator system considering a realistic head geometry. For more accurate design and computer simulations, a realistic volume conductor model was adopted and the current evoked on human cerebral cortex was analyzed using the boundary element method (BEM). To obtain a more focalized evoked current around the target points, various coil configurations were tested and an average targeting error of about 10 mm was obtained.

중대뇌동맥 허혈에 의한 파페츠 회로 손상과 작화증 (Confabulation Following Injury of the Papez Circuit as a Result of Middle Cerebral Artery Infarction: A Diffusion Tensor Tractography Study)

  • 여상석
    • PNF and Movement
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    • 제14권1호
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    • pp.41-47
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    • 2016
  • Purpose: In general, confabulation is defined as confusion of reality with past events without apparent prompting, in association with disruption of the capacity for retrieval and encoding of memory. We report on a patient who showed spontaneous confabulation associated with injury of the Papez circuit following middle cerebral artery (MCA) infarction. Methods: A 67-year-old female patient suffered cerebral infarct resulting from spontaneous MCA territory. After onset of the MCA infarct, she showed severe memory impairment and provoked confabulation. The Papez circuit was reconstructed for evaluation of part of it using diffusion tensor tractography (DTT). Fractional anisotropy (FA), mean diffusivity (MD), and tract volume were measured. Results: The right thalamocingulate tract showed a significant decrement of FA value and tract volume, and an increment of MD value by more than two standard deviations of that of normal control subjects. The tract volume in the left fornix and mammillothalamic tract decreased by more than two standard deviations of that of normal control subjects. Conclusion: Injuries of the Papez circuit were demonstrated in a patient who showed severe memory impairment and provoked confabulation following MCA infarct. We believe that analysis of the Papez circuit tract using DTT is useful in elucidating the cause of provoked confabulation in patients with MCA infarct.

웨스팅하우스형 원자력발전소 가압기 방출 탱크의 실시간 시뮬레이션을 위한 전문모델 개발 (Development of a Dedicated Model for a Real-Time Simulation of the Pressurizer Relief Tank of the Westinghouse Type Nuclear Power Plant)

  • 서재승;전규동
    • 한국시뮬레이션학회논문지
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    • 제13권2호
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    • pp.13-21
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    • 2004
  • The thermal-hydraulic model ARTS which was based on the RETRAN-3D code adopted in the domestic full-scope power plant simulator which was provided in 1998 by KEPRI. Since ARTS is a generalized code to model the components with control volumes, the smaller time-step size should be used even if converged solution could not get in a single volume. Therefore, dedicated models which do not force to reduce the time-step size are sometimes more suitable in terms of a real-time calculation and robustness. In the case of PRT(Pressurizer Relief Tank) model, it is consist of subcooled water in bottom and non-condensable gas in top. The sparger merged under subcooled water enhances condensation. The complicated thermal-hydraulic phenomena such as condensation, phase separation with existence of non-condensable gas makes difficult to simulate. Therefore, the PRT volume can limit the time-step size if we model it with a general control volume. To prevent the time-step size reduction due to convergence failure for simulating this component, we developed a dedicated model for PRT. The dedicated model was expected to provide substantially more accurate predictions in the analysis of the system transients. The results were resonable in terms of accuracy, real-time simulation, robustness and education of operators, complying with the ANSI/ANS-3.5-1998 simulator software performance criteria and RETRAN-3D results.

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국내산 전립분을 첨가한 식빵의 품질 특성 (Quality Characteristics of Pan Bread with the Addition of Korean Whole Wheat Flour)

  • 송영광;황윤경;이희태;안혜령
    • 동아시아식생활학회지
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    • 제23권5호
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    • pp.586-596
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    • 2013
  • This study was designed to investigate the effect of Korean whole wheat flour making pan bread. Korean whole wheat flour was mixed with flour at the level of 10% (WHF10), 20% (WHF20), 30% (WHF30), 40% (WHF40) and 50% (WHF50) in order to make bread. According to mixogram, the CON (control), WHF10, WHF20, WHF30, WHF40, except WHF50 were found to be proper between 3 and 5 min. in terms of peak time. CON and WHF10 for peak value were at the level of over 60%. By increasing the ratio of Korean whole wheat flour, the pH, dough fermentation rate, volume, specific volume and moisture content were decreased, and gumminess, cohesiveness and hardness except springiness, were increased for storage days. In the crumbScan analysis, the addition of Korean whole wheat flour decreased the volume and increased the crumb fineness of pan bread. In the sensory evaluation, WHF30 showed good preference in the aspect of flavor, taste and overall acceptance, but was not significant between WHF20. CON scored the highest points in volume, specific volume, moisture content and texture, but was not significant between WHF20.

Structure of a single polymer chain confined in a dense array of nanoposts

  • Joo, Heesun;Kim, Jun soo
    • EDISON SW 활용 경진대회 논문집
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    • 제4회(2015년)
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    • pp.48-52
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    • 2015
  • Control of polymer conformations in heterogeneous confinement plays an important role in natural and engineering processes. We present a simulation study on the conformational structure and dynamics of a single, flexible polymer in a dense array of nanoposts with different sizes and separations, especially, when the volume of the interstitial space formed between four nanoposts is less than the size of the polymer chain. When a polymer is placed in the array of nanoposts, the size of polymer increases compared with that in the absence of nanoposts due to the confinement effect. It is shown that when a polymer is confined in the array of nanoposts the chain is elongated in the direction parallel to the nanoposts. As the interstitial volume between four nanoposts decreases either by increasing the nanopost diameter or by decreasing the separation between nanoposts, the chain elongation becomes more pronounced. On the contrary, the polymer size varies in a non-monotonic fashion, with an initial elongation followed by a chain contraction, as the interstitial volume is reduced both by increasing the nanopost diameter and decreasing the separation at the same time while keeping constant the width of the passageway between two nanoposts. The simulation analysis shows that the non-monotonic dependence of polymer size is determined by interplay between the chain alignment along the nanoposts in each interstitial volume and the chain spreading through passageways over several interstitial volume.

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도로밀도에 대한 소하천 유역 기반의 총량규제 기초자료 확보 방안 (Acquisition of Evidential Information to Control Total Volume of Road Density per Tributary Watershed)

  • 엄정섭
    • 환경영향평가
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    • 제14권5호
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    • pp.317-335
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    • 2005
  • This paper is primarily intended to propose a new concept of "aggregate control of road density" which is defined as the area-wide road surface per watershed area. An empirical study for experimental sites was conducted to confirm how a standard GIS technology can be used to assist in estimating the road density in terms of total volume threshold control. Guidelines for a replicable methodology are presented to provide a strong theoretical basis for the standardization of factors involved in the estimation of the road space threshold; the meaningful classification of road types, delination of watershed boundary, interpretation for distribution trends of road density etc. A variety of visual maps using overlay analysis can be generated over large areas quickly and easily to show the fact that some degree of road space already exists in the experimental sites. They could be used as an evidence to limit further construction of road network in comparison with other tributary watershed. It is anticipated that this research output could be used as a valuable reference to confirm the potential of introducing the new concept of "site specific road density" to support more scientific and objective decision-making in the process of road construction project.

CFD를 사용한 평행 홈 펌프 시일의 해석 개선 (Improvement on Prediction of Circumferential-Groove-Pump Seal with CFD Analysis)

  • 하태웅
    • Tribology and Lubricants
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    • 제24권6호
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    • pp.291-296
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    • 2008
  • In order to improve the leakage prediction and rotordynamic analysis of an annular seal with a smooth rotor and circumferentially grooved stator, CFD analysis using FLUENT has been performed to determine the groove penetration angle a which is the angle of separation line between control volumes II and III in groove section of Ha and Lee's three-control-volume theory. Validation to the present analysis using new penetration angle determined by the CFD analysis is achieved by comparisons with the results of published Ha and Lee's analysis. For the leakage prediction the present analysis shows slight improvement and CFD results yields the best. Direct damping and cross-coupled stiffness coefficients are predicted better to the experimental ones. However, direct stiffness coefficient is predicted worse.