• Title/Summary/Keyword: Stokes 수

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Real-time Fluid Animation using Particle Dynamics Simulation and Pre-integrated Volume Rendering (입자 동역학 시뮬레이션과 선적분 볼륨 렌더링을 이용한 실시간 유체 애니메이션)

  • Lee Jeongjin;Kang Moon Koo;Kim Dongho;Shin Yeong Gil
    • Journal of KIISE:Computer Systems and Theory
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    • v.32 no.1
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    • pp.29-38
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    • 2005
  • The fluid animation procedure consists of physical simulation and visual rendering. In the physical simulation of fluids, the most frequently used practices are the numerical simulation of fluid particles using particle dynamics equations and the continuum analysis of flow via Wavier-Stokes equation. Particle dynamics method is fast in calculation, but the resulting fluid motion is conditionally unrealistic The method using Wavier-Stokes equation, on the contrary, yields lifelike fluid motion when properly conditioned, yet the complexity of calculation restrains this method from being used in real-time applications. Global illumination is generally successful in producing premium-Duality rendered images, but is also excessively slow for real-time applications. In this paper, we propose a rapid fluid animation method incorporating enhanced particle dynamics simulation method and pre-integrated volume rendering technique. The particle dynamics simulation of fluid flow was conducted in real-time using Lennard-Jones model, and the computation efficiency was enhanced such that a small number of particles can represent a significant volume. For real-time rendering, pre-integrated volume rendering method was used so that fewer slices than ever can construct seamless inter-laminar shades. The proposed method could successfully simulate and render the fluid motion in real time at an acceptable speed and visual quality.

Effect of Pressure on Hydration Number of Some Ions (몇 가지 이온의 水和數에 대한 壓力의 效果)

  • Jung-Ui Hwang;Jong-Jae Chung;Hag-Sung Kim
    • Journal of the Korean Chemical Society
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    • v.36 no.6
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    • pp.791-795
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    • 1992
  • The limiting equivalent conductances of LiCl, NaCl, KCl and KBr have been obtained in water using conductometric method from 1 to 2000 bars at $25^{\circ}C$. From the limiting equivalent ionic conductances (obtained using TATB[Tetraphenyl Arsonium Tetraphenyl Borate]method) of $Li^+$, $Na^+$, $K^+$, $Cl^-$, and $Br^-$ ions and viscosity of water at given pressure, their Stokes radii have been calculated. From the corrected radii caliberated by Nightingale method and the crystallographic radii at a given pressure, the volume of hydration-shell surrounding ion was calculated and hydration numbers of $Li^+$, $Na^+$, $K^+$, $Cl^-$, and $Br^-$ ions were obtained. From the experimental results, it was found that the hydration number of $Li^+$, $Na^+$, $K^+$, $Cl^-$, and $Br^-$ ions slightly decreased with increasing pressure. This trend may be explained by Horne's suggestion[Advances in High Pressure Research]. Comparing results of this study with those of Nakahara's, the hydration numbers of $K^+$ and $Cl^-$ ions were almost twice as large as those of Nakahara's[Rev. Phys. Chem. Japan, 42, 12 (1972)]. By comparing the present results with those of Kollman's [J. Am. Chem. Soc., 113, 2481 (1991)], the hydration number obtained by applying TATB method and Nightingale method may be inferred to be reasonable.

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석탄가스화기내의 미분탄 입자를 동반한 유동장 해석

  • 이진욱;마수만;김원배
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
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    • 1995.11a
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    • pp.5-14
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    • 1995
  • 본 연구는 석탄가스화기내의 비반응 유동장에 대한 연구로서, 순수유동장 및 미분탄입자를 포함한 이상유동장에 대한 전산해석을 수행하였다. 가스화기내의 물리적 현상을 기술하는 Navier-Stokes 방정식을 유한차분법에 의하여 해석하고 그 결과를 나타내었다. 특히 선회유동의 영향에 의한 미분탄입자의 거동 및 재순환영역의 특성에 대하여 상세히 고찰하였다. 해석결과에 의하면 가스화기내에서는 몇개의 재순환영역이 형성됨을 알 수 있었다. 비반응유동장의 해석결과이지만, 선회유동은 화염안정화에 긍정적인 영향을 줄 수 있을 것으로 추측되는 결과를 보였다.

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Flow Measurement and Analysis of the Waterjet Duct (물분사추진기 관내 유동계측 및 유동해석)

  • 왕정용;최희종;전호환;차상명
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2001.05a
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    • pp.240-243
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    • 2001
  • 괘도차량에 부착된 물분사추진기의 유동해석을 실험과 포텐셜해석 그리고 점성해석을 사용하여 그 결과를 비교하였다. 예인수조에서 여러 차량 전진속도에 대해서 임펠러 회전수를 조정하여 제트속도를 변화시키면서 덕트표면에서의 정압을 계측하였다. 이는 제트시스템의 효율을 추정하기 위함이고 관로를 통한 에너지분포를 알 수 있다. 점성유동해석을 위해 지배방정식은 비압축성 Navier-Stokes 방정식을 유한체적법을 사용하여 이산화하고 해석하였으며 난류영향은 표준 ĸ-$\varepsilon$난류모형을 사용하여 유동을 해석하고 실험결과 및 포텐셜 해석결과와 비교하였다.

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Adrenal Metastasis from Renal Cell Carcinoma Regressed with Allergen-removed Rhus verniciflua Stokes;A Case Report (알러젠 제거 옻나무 추출물 투여로 소퇴된 신세포암 유래 부신전이암 1례)

  • Jeong, Ui-Min;Jeong, Jong-Soo;Jung, Hyun-Sik;Park, Jae-Woo;Yoon, Seong-Woo
    • The Journal of Internal Korean Medicine
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    • v.29 no.2
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    • pp.529-534
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    • 2008
  • Renal cell carcinoma(RCC) is one of the major malignant renal cell tumors. Although RCC can metastasize to almost every organ, the most common metastatic sites are the lung parenchyma, the bones, the liver, and the brain. Adrenal metastasis from RCC is extremely rare. Adrenal metastasis from RCC shows poor prognosis, with little benefit from chemotherapy, radiation therapy, hormone therapy or immunotherapy. In this report, we describe a case of an RCC patient who showed lung and adrenal metastasis. The patient underwent left nephrectomy and chemotherapy(sunitinib), which were not effective. He refused further conventional medical treatment, and instead started treatment with Traditional Korean Medicine using allergen-removed Rhus verniciflua Stokes. After about 3 months of this treatment, the size of the adrenal tumor had decreased significantly with good performance status. Further study will be needed to demonstrate the tumor regression effect of allergen-removed Rhus verniciflua Stokes on patients with metastatic renal cell carcinoma.

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Mixing Characteristics in Supersonic Combustor with a Cavity (Cavity를 이용한 초음속 연소기 내의 혼합특성)

  • Oh Juyoung;Bae Young-Woo;Kim Ki-Su;Jeon Young-Jin;Lee Jae-Woo;Byun Yung-Hwan
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • v.y2005m4
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    • pp.359-363
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    • 2005
  • In SCRamjet engine, combustion occurs in supersonic flow with airbreathing. SCRamjet is characterized by very short combustion time in combustor, so it is very important to be mixing the air and fuel in short duration. Several methods are suggested for mixing enhancement. Among these, cavity is selected to study for enhancement of mixing. The numerical simulation is performed in the case of freestream Mach number of 2.5 and cavity located in front of fuel jet injection. CFD-Fastran, commercial code with three-dimensional Navier-Stokes equation with the Menter SST turbulence model were used. The results are obtained validate experiment results for same condition. Therefore, the numerical results show the mixing enhancement characteristics with a cavity.

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Computational Aerodynamic Analysis of Airfoils for WIG(Wing-In-Ground-Effect) -Craft (지면효과익기 날개에 대한 전산 공력 해석)

  • Joh, Chang-Yeol;Kim, Yang-Joon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.32 no.8
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    • pp.37-46
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    • 2004
  • Several notes on ground effects drawn from Navier-Stokes analyses and their aerodynamic interpretations were addressed here; For two-dimensional ground effect, the change of surface pressure due to image vortex, the venturi effect due to thickness and the primary inviscid flow phenomena of ground effect, and for three-dimensional ground effect, strengthened wing tip vortices, increased effective span and the outward drift of trailing vortices. Irodov's criteria were evaluated to investigate the static longitudinal stability of conventional NACA 6409 and DHMTU 8-30 airfoils. The analysis results demonstrated superior static longitudinal stability of DHMTU 8-30 airfoil. The DHMTU airfoil has quite lower value of lrodov's criterion than the conventional NACA airfoil, which require much smaller tail volume to stabilize the whole WIG-craft at its design stage.

Aerodynamic Design Optimization of Airfoils for WIG Craft Using Response Surface Method (반응표면법을 이용한 지면효과익기 익형의 공력 설계최적화)

  • Kim, Yang-Joon;Joh, Chang-Yeol
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.5
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    • pp.18-27
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    • 2005
  • Airfoils with improved longitudinal static stability were designed for a WIG craft through aerodynamic design optimization. The response surface method is coupled with NURBS-based shape functions and Navier-Stokes flow analysis. The procedure runs in the network-distributed design framework of commercial-code based automated design capability to enhance computational efficiency and robustness.Lift maximization design maintaining similar static margin to a DHMTU airfoil successfully produced a new airfoil shape characterized by pronounced front-loading and the well-known reflexed aft-camber line. Another airfoil design of lower variation in pitching moment during take-off showed weakened front-loaded characteristics and hence decreased lift slightly. Investigations using the present design methodology on an existing optimization result based on potential flow analysis and NACA-type geometry generation demonstrated significance of carrying various geometry generations and more realistic flow analysis with optimization.

A Case of Advanced Gastric Cancer Patient Treated with Sojeukjungwon-san and Allergen Removed Rhus Verniciflua Stokes(aRVS) (소적정원산(消積正元散) 및 옻나무 추출물 투여로 체중증가 및 일반활동도의 개선을 보인 진행성 위암환자 1례)

  • An, Ji-Hye;Jerng, Ui-Min;Jeong, Jong-Soo;Park, Jae-Woo;Yoon, Seong-Woo
    • Journal of Korean Traditional Oncology
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    • v.14 no.1
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    • pp.21-27
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    • 2009
  • Advanced gastric cancer is the most common type of all cancers in Korea, which account for approximately 18.1% of all incident cancers, and mortality from advanced gastric cancer is estimated at nearly 15.6% of death that caused by all cancer. In the conventional medicine, treatments of advanced gastric cancer include chemotherapy such like FOLFOX. In this case report, we introduce a case of advanced gastric cancer with greater omentum, thyroid, supraclavicular lymph node metastasis who had received chemotherapy. Chemotherapy was stopped because of weight loss and neurologic symptom such like cognitive disorder. The patient visited $M{\cdot\mu}$ Integrative cancer center in 2008, and was treated by Sojeukjungwon-san and allergen removed Rhus verniciflua stokes(aRVS). There was no evidence of brain metastasis. The patient showed improvement of cognitive disorder and gained weight. Further case study will be needed in order to determine the effects of Sojeukjungwon-san and allergen removed Rhus verniciflua stokes(aRVS) for the quality of life of advanced gastric cancer patients after chemotherapy.

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Protective Mechanism of Flavonoids Isolated from Rhus Vernicifiua on the Paraquat Toxicity Reducing Agent and its Inhibition Mechanism (옻나무 목부로부터 분리한 Favonoids가 Paraquat 독성의 경감기전 검색)

  • 김정수;조희숙;강혜옥;한갑이;정민화;최종원
    • Journal of Life Science
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    • v.13 no.6
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    • pp.775-781
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    • 2003
  • In this study, we investigated to elevate the modulatory effect of flavonoid(fustin, sulfuretin, 10 mg/kg) which was isolated from Rhus verniciflua Stokes(RVS) in male Sprague-Dawley rats for 2 weeks on the toxicity of paraquat. In the flavonoids pretreated groups, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, blood urea nitrogen, creatinine, malondialdehyde and alkaline phosphatase activity in serum and malondialdehyde, alkaline phosphatase activity and collagen in lung tissue which was induced paraquat toxicity were slightly decrease compared to the normal group. In the lung tissue of flavonoids pretreated groups, malodialdehyde value, G-6-phosphatase activity and collagen synthesis were recovered to tile normal values and alkaline phosphatase activity was increased. From these results, we concluded that flavonoids which were isolated from RVS is an effective agent to inhibit the pulmonary and internal toxicities and hence we concluded that acitive components of fustin and sulfuretin which were isolated from RVS might be removed free radicals induced by paraquat.