• Title/Summary/Keyword: Stagnation point

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Study to Develop the Instrument of Pattern Identification for Hwa-byung (화병변증도구 개발 연구)

  • Yim, Hyeon-Ju;Kim, Seok-Hwan;Lee, Sang-Ryong;Jung, In-Chul
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.22 no.5
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    • pp.1071-1077
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    • 2008
  • Hwa-byung is a form of psychogenic illness among people in Korea and is listed as a culture-bound syndrome of Korea in the DSM-IV. Despite increased clinical researches for Hwa-byung in the oriental medicine of Korea, there has been no agreement of pattern identification for Hwa-byung. The purpose of this study is to develop a standard instrument of pattern identification for Hwa-byung which will be applied to clinical research. The items and structure of the instrument were based on review of published literature. The advisor committee on this study was organized by 15 neuropsychiatry professors of 11 oriental medical colleges nationwide. The experts attended 2 consultation meetings and discussed developing the instrument. and we also took professional advices by e-mail. The results were as follows; First, we divided the symptoms and signs of Hwa-byung into five pattern identification - stagnation of liver Qi, flare-up of the liver fire, disharmony between heart and kidney, deficiency of both Qi and blood, malfunction of gallbladder due to phlegm stagnation. Second, we got the mean weights to each symptom of five pattern identification which had been scored on a 5-point scale - ranging from 0 to 4 by the 15 experts. Third, we made out the Korean instrument of the pattern identification for Hwa-byung. It was composed of 34 questions and decided on question-and-answer form. Though there are some limits in this study, the instrument of pattern identification for Hwa-byung is meaningful and expected to be applied to the subsequent research. And also, we hope to improve the instrument and make up for this study through various research and discussion.

Effects of Nonequilibrium Condensation on an Oblique Shock Wave in a Supersonic Nozzle of Constant Expansion Rate (팽창률이 일정한 초음속 노즐흐름에 있어서 비평형 응축이 경사충격파에 미치는 영향)

  • 강창수;권순범;김병지;홍종우
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.5
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    • pp.1311-1319
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    • 1990
  • For the purpose of preventing the flow undulation in the cascade of steam turbine, the blades are made into a constant expansion rate in static pressure. And the flow in those cascades is transonic or supersonic in the range of 0.7-2.0 in Mach number. As a consequence, an oblique shock wave, known as inner or outer edge shock wave, arises in the flow of cascades. Especially when the steam in cascades is in a state of high wetness, nonequilibrium condensation and condensation shock wave occur, and they give rise to an interference with oblique shock wave. In the present study the case of expansion of moist air through a supersonic nozzle of constant expansion rate, which behaves similar to that of wet steam, was adopted. The effect of nonequilibrium condensation on the oblique shock wave generated by placing the wedge into the supersonic part of the nozzle was investigated. Furthermore, the relationship between nonequilibrium condensation zone and incident point of the oblique shock wave, oblique shock wave angle, the variations of angles of incident and reflected shock waves due to the variation of initial stagnation supersaturation and the relationship between the height of Mach stem and initial stagnation supersaturation are discussed.

Flow and Heat Transfer Characteristics on Oblique Impingement Surface by Single Axisymmetric Jet (단일 축대칭제트에 의한 경사충돌면에서 유동 및 열전달 특성)

  • 이창호;황상동;조형희;정학재
    • Journal of the Korean Society of Propulsion Engineers
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    • v.3 no.1
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    • pp.34-40
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    • 1999
  • An experimental study has been conducted to determine the effects of inclined impinging jet on the local heat transfer coefficients. A single jet with nozzle diameter of 24.6 mm was tested for Reynolds numbers from 10,000 to 70,000 and nozzle-to-plate spacings of 2~6 jet diameters. The angle of inclination of the impingement surface relative to the horizontal surface was varied from $0^{\cire}$ (normal impingement) to $60^{\cire}$. The results indicate that the point of maximum heat transfer is moved up from the geometrical stagnation point of inclined surface by Coanda effect. The local heat transfer coefficients on the minor jet region decrease more rapidly than on the major jet region, thus creating an imbalance in the cooling capabilities on the two sides.

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A Study on the Effect of Scale Roughness attached Surface of Heat Exchangers (표면에 부착되는 스케일의 조도가 열교환기 성능에 미치는 영향에 관한 연구)

  • Kim, Min-Soo;Choi, Nag-Jung
    • Journal of Advanced Marine Engineering and Technology
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    • v.34 no.2
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    • pp.235-242
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    • 2010
  • An experimental investigation has been conducted to clarify roughness effects of geothermal water scale deposited onto a heating surface upon its forced convection heat transfer characteristics. Examined was a circular cylinder, on which particles of silica scale having five different sizes are uniformly distributed. The Reynolds number was varied from 13000 through 50000. Local and mean heat transfer characteristics were measured as functions of particle size and Reynolds number. Subsequently the mean fouling resistance was estimated from those results, and its characteristics are clarified. It was found that the heat transfer of cylinders greatly varies with the fouling of geothermal water scale, especially its scale height. Further, the local and average Nusselt numbers strongly depend upon the cylinder spacing and the Reynolds number.

Changes in the Performance Industry Due to Social Distancing : Case Analysis of Online Performance Platforms (사회적 거리두기로 인한 공연산업의 변화 : 온라인공연 플랫폼 사례분석)

  • Kim, Jae-Sung;Han, Kyung-Hoon
    • Journal of Korea Entertainment Industry Association
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    • v.15 no.5
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    • pp.1-17
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    • 2021
  • Social distancing caused a sharp industrial stagnation in the performance industry. Due to the continuous industrial downturn, as well as the livelihoods of many related workers, the outlook for the performance industry has reached a point where it is impossible to foresee the future. As a result of seeking various ways to recover from the continuing industrial stagnation, online concerts drew attention as the most effective alternative. Its development potential was highly evaluated as it could provide a performance culture to consumers while complying with social distancing. This study has value in terms of academic contribution as it slightly suggests a direction for the sustainable development of online performances presented as a breakthrough amid the social and industrial stagnation caused by the pandemic. therefore, this thesis describes the changes in the performance industry due to social distancing, and collects and analyzes examples of online performances by type to illuminate the value of online performances as an industry in the pandemic era and develops them. The possibility was reconsidered and the direction to be taken in the future was suggested. In each type of case, the cases focused on social value did not satisfy the economic value of profit creatiom, and even in the opposite case, if the profit creation was satisfied, the analysis result showed that the social value was not satisfied, and the planning intention of each performance was not satisfied. Accordingly, cases such as satisfying both profit creation and social value were also confirmed. Therefore, the direction for online performances was presented through the improvement of technologies and systems and the commercialization of existing platforms.

Investigation of the gas Dynamics in an Upflow OMVPE Reactor by Raman Spectroscopy

  • Park, Chinho;Timoghy J. Anderson
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • 1997.06a
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    • pp.223-228
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    • 1997
  • The gas dynamics in a stagnation point upflow OMVPE reactor were studied by Raman spectroscopy. The gas temperature was measured as a function of inlet gas velocity and aspect ratio for both H$_2$ and N$_2$ carrier gases. The centerline temperature gradient was latger at higher inlet velocities and with the use of N$_2$, and only weakly dependent on the aspect ratio. a tracer molecule, CH$_4$, was used to investigate the steady state behavior of reactants in the reactor, and the use of a sweeping flow was found to be a suitable method for preventing wall deposition. The transient switching response of the gas manifold was also investigated. Under certain conditions (low velocities, unmatched flows) recirculation flows were apparent. Numerical calculations of the reactor gas dynamics gave reasonable agreement with experimental results when detailed thermal boundary conditions were included.

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NBI 가열 플라즈마에서 고속이온 분포의 수치적 계산 및 측정결과 비교

  • Wang, Seon-Jeong;Kim, Seon-Ho;Kim, Seong-Gyu
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.263-263
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    • 2012
  • 핵융합 플라즈마에서의 고속이온은 NBI 및 ICRF에 의한 이온 가열과 핵융합 반응에 의하여 발생하며, 핵융합 반응률을 크게 하고 일차적으로 그 에너지를 전자에게 전달하는 특성을 갖는다. 따라서 핵융합을 지향하는 플라즈마에서는 그 성능을 나타내는 지표이기도 하면서, 맥스웰 분포를 갖는 열화 플라즈마의 수송특성을 크게 변화 시킨다. 또한 알펜파 등의 파동 또는 불안정성을 유발시키며 이로 인한 플라즈마 손실은 국지적인 일차벽의 가열을 유발할 수 있는 것으로 여겨진다. 본 연구에서는 일반적인 기하학적 구조를 갖는 토카막에서의 NBI 가열에 의한 고속이온 발생과 위상공간에서의 수송 및 손실을 시간 의존적인 Fokker-Planck 방정식을 수치적으로 풀어서, 위치에 따른 고속이온 분포의 변화를 계산한다. NBI 입사의 기하학적 모델에서는 각 계산 위치에서의 피치각 변화와 stagnation point의 변화에 의한 영향을 고려하며, 일반적인 고속이온의 각종 모멘트 뿐 아니라 즉발 이온 손실률을 계산에 포함한다. 해석된 고속이온 분포는 중성입자 검출기에서 측정한 KSTAR 플라즈마의 고속이온 에너지 분포와 비교한다. 차후에는 본 연구에서 사용한 Fokker-Planck 출동연산자에 고주파 가열에 의한 고속이온발생 항을 추가하여 ICRF 가열에 의한 효과를 예측할 수 있도록 할 것이다.

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Gas phase temperature profile measurement of an upflow OMVPE reactor by laser Raman spectroscopy (레이저 라만 분광법을 이용한 도립형 OMVPE 반응기의 기상 온도 분포 측정)

  • ;Timothy J. Anderson
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.8 no.3
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    • pp.448-453
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    • 1998
  • An inverted, stagnation point flow OMVPE reactor was studied by laser Raman spectroscopy. Pure rotational Raman scattering by the carrier gas $(N_2; or; H_2)$ was used to determine the axial centerline temperature profile in the reactor as a function of the inlet flow velocity and the rector aspect ratio. A larger temperature gradient normal to the susceptor surface was obtained with higher gas glow velocity, larger aspect ratio, and the use of a $N_2$ carrier gas.

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POSSIBLE MERGER SIGNATURE IN SZ MAPS

  • KOCH PATRICK
    • Journal of The Korean Astronomical Society
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    • v.37 no.5
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    • pp.471-476
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    • 2004
  • We propose an analytical model to estimate the influence of a merger on the thermal SZ effect. Following observations we distinguish between subsonic and transonic mergers. Using analytical velocity fields and the Bernoulli equation we calculate the excess pressure around a moving subcluster for an incompressible subsonic gas. Positive excess around the stagnation point and negative excess on the side of the subcluster lead to characteristic signatures in the SZ map, of the order of $10\%$ compared to the unperturbed signal. For a transonic merger we calculate the change in the thermal spectral SZ function, resulting from bow shock accelerated electrons. The merger shock compression factor determines the power law tail of the new non-thermal electron population and is directly related to a shift in the crossover frequency. This shift is typically a few percent towards higher frequencies.

Study of Energy Separation Mechanism in Vortex Tube by CFD (볼텍스 튜브의 에너지 분리 현상에 관한 수치해석 연구)

  • Choi, Won-Chul;Chung, Myung-Kyoon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.32 no.2
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    • pp.92-99
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    • 2008
  • The "energy separation phenomenon" through a vortex tube has been a long-standing mechanical engineering problem whose operational principle is not yet known. In order to find the operational principle of the vortex tube, CFD analysis of the flow field in the vortex tube has been carried out. It was found that the energy separation mechanism in the vortex tube consists of basically two major thermodynamic-fluid mechanical processes. One is the isentropic expansion process at the inlet nozzle, during which the gas temperature is nearly isentropically cooled. Second process is the viscous dissipation heating due to the high level of turbulence in both flow passages toward cold gas exit as well as the hot gas exit of the vortex tube. Since the amount of such a viscous heating is different between the two passages, the gas temperature at the cold exit is much lower than that at the hot exit.