• Title/Summary/Keyword: Stagnation

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Numerical Analysis for Thermal Design of Electronic Equipment Using Phase Change Material (상변화 물질을 이용한 전자 장비 방열 설계의 수치 해석적 연구)

  • Lee, Dong Kyun;Lee, Won Hee;Park, Sung Woo;Kang, Sung Wook;Cho, Ji Hyun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.41 no.4
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    • pp.285-291
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    • 2017
  • In this study, a case analysis for thermal design of electronic equipment using a phase change material(PCM) was performed numerically using ANSYS Fluent. Experiments were conducted to find the temperature increase(${\Delta}T_m$), melting temperature($T_m$), and volume expansion of the PCM under the melting process. To verify the accuracy of the Fluent solver model, $T_m$, ${\Delta}T_m$, and the melting time were compared with experimental results. To simulate the temperature stagnation phenomenon under the melting process, the equivalent specific heat method was applied to calculate the thermal properties of the PCM in the solver model. To determine the thermal stability of electronic equipment, we paid special attention to finding a thermal design for the PCM using fins. Further, an additional numerical analysis is currently underway to find an optimum design.

Blood Flow Changes by Anastomotic Method in Fontan Operation (폰탄 수술에서 문합방법에 따른 혈류 변화)

  • Kim, S.H.;Park, Y.H.;Cho, B.K.;Kim, J.H.;Hong, Y.S.;Kim, Y.H.;Kim, S.S.
    • Proceedings of the KOSOMBE Conference
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    • v.1996 no.05
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    • pp.203-206
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    • 1996
  • To understand the local fluid dynamics for different desists of Fontan operation, five models were made out of Pyrex glass to facilitate in-vitro study. Model I, II and III have same position of the center of the anastomosis of the IVC( inferior vena cava) with that of the SVC(superior vena cava), but Model IV and V have 10 mm offset between them. Also the anastomotic junction angles are different(Model I and $IV:90^{\circ}$, Model II and $V:70^{\circ}$, Model $III:45^{\circ}$). These models were then connected to a flow loop for flow visualization study. In Model I any dominant vortex was not seen in the central region of the juntion, but a large unstable vortex was created in the Model II and III. In Model IV and V a significant stagnation region was created in the middle of the offset region. It also showed that the flow direction from the IVC and SVC to the LPA(left pulmonary artery) and RPA(right pulmonary artery) highly depends on the offset of the junction rather than the anastomotic junction angle.

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Two Cases Report of Herpes Zoster Patients Improved by Korean Medicine Treatment alone (대상포진에 대한 한방 단독 치료 치험 2례)

  • Bae, Jae Ryong;Kim, Su Jin;Jang, Sang Chul;Pi, Chien Mei;Roh, Ju Hee
    • Journal of Korean Medical Ki-Gong Academy
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    • v.16 no.1
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    • pp.116-136
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    • 2016
  • Objectives : The purpose of this study is to report a 67-year-old male patient with Herpes zoster(caseI) and a 38-year-old female patient with Herpes zoster(caseII), whose symptoms were relieved after Korean medicine treatment alone. Methods : Both patients took Yeonryeonggobondan and Pyungwee-san daily. Everytime they came to the hospital, they received acupuncture treatment, Hwidam's Su-Gi therapy and External Gigong Therapy. Acupuncture was applied by gall bladder seunggyeok(膽勝格, GB-), spleen jeonggyeok(脾正格, SP+), large intestine seunggyeok(大腸勝格, LI-) of Saam's Acupuncture Method. Hwidam's Su-Gi therapy was applied on neck. External Gigong Therapy was applied on skin lesion area. the patients' symptoms were evaluated with photographs and VAS. Results : The results were as follows: 1. In the case of a 67-year-old male patient, it took 14 days to recover the skin lesions and to reduce the pain after treatment started. And he visited 13 times during that period. 2. In the case of a 38-year-old female patient, it took 23 days to recover the skin lesions to reduce and the pain after treatment started. And she visited 10 times during that period. 3. Intensive treatment early in treating herpes zoster helped to shorten the treatment period. 4. Taking Yeonryeonggobondan and Pyungwee-san and receiving acupuncture treatment(SP+) can help to improve immunity and recover skin lesions in herpes zoster diagnosed with spleen deficiency with dampness encumbrance(脾虛濕困) and blood stasis due to qi stagnation (氣滯血瘀). 5. The combination of acupuncture treatment(GB-) and External Gigong Therapy was effective in controlling pain. 6. External Gigong Therapy is considered to be effective for the recovery of the skin as well as the pain of the herpes zoster. Conclusions : Korean medicine treatment alone has a great effect on the above two patients with herpes zoster. I hope the active research about Korean medicine treatment will be done not only for herpes zoster but also for various intractable pain diseases.

The Study on the Treatment of Leiomyoma - Focusing on the Papers Published in 2010 within China - (자궁근종의 치료에 대한 고찰 -2010년 중국내 발표 논문 중심으로-)

  • Baek, Young-Ju;Kim, Myoung-Dong
    • The Journal of Korean Obstetrics and Gynecology
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    • v.24 no.1
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    • pp.109-131
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    • 2011
  • Objectives: This study aims to search the clinical cases that treated leiomyoma through the traditional Chinese medicine, to understand the study trend on leiomyoma in China, and to clairfy the cause of leiomyoma and its treatment by the oriental medicine herbs. Methods: We searched the key word "leiomyoma" in the China National Knowledge Infrastructure (CNKI)[http://www.cnki.net], and narrowed its searching area to the papers published in the year 2010. Of 720 study papers, we chose 21 clinical papers on the leiomyoma, and studied the patient case, treating method, result of treatment, and checked the category, cause, treatment method of leiomyoma. Results: The results are shown in the Table 1-3. Conclusions: Leiomyoma is categorized in the traditional Chinese medicine as both lump occuring inside the body and stony abdominal lump. The main cause of leiomyoma is qi-stagnation and blood stasis, essence deficiency and pathogen affluence. The treatment method is used by activating blood and resolving stasis but harmonizing the spleen and stomach to prevent damaging healthy qi. The development herbal medicine of treating leiomyoma is Gyehongbyeolgaphwan, Gyejibongnyeonggyonang, Gungryusogyonang, Angonpyoen etc. In treating leiomyoma, the herbs were much used to regulate qi as Baekbokryung, Danggwi, Baekchul, Doin, Moryeo, Achul, Mokdanpi etc. Traditional Chinese Medicine(TCM) treatment of leiomyoma has efficiency of improve symptom but low ratio of complete recovery.

Development of a Guideline for the Application of a Diagnostic Tool for Menopausal Syndromes Based on the Use of Systemic Review and Delphi Method (체계적 문헌고찰과 델파이 기법을 활용한 갱년기장애 변증(辨證)진단 도구 개발을 위한 기초 연구)

  • Lee, In-Seon;Kim, Dong-Il;Yoo, Jeong-Eun;Kang, Chang-Wan
    • The Journal of Korean Obstetrics and Gynecology
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    • v.30 no.4
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    • pp.175-202
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    • 2017
  • Objectives: This study was conducted towards developing a screening tool for syndrome differentiation in the diagnosis of menopause in menopausal and perimenopausal women. Methods: We conducted a literature review of studies on menopausal diagnosis based on syndrome differentiation, and examined well-founded differentiated syndromes and their respective clinical symptoms. Based on the findings, we created a questionnaire through consultations with Oriental medicine experts in physiology, pathology, and diagnostics. Finally, the research team conducted an expert Delphi study on differentiated syndromes and the associated clinical symptoms. Results: Seven differentiated syndromes were selected, including Liver Depression (肝鬱), Kidney Yin Deficiency (腎陰虛), Kidney Yang Deficiency (腎陽虛), Liver and Kidney Yin Deficiency (肝腎陰虛), Kidney Yin and Yang Deficiency (腎陰陽兩虛), Heart-Kidney Noninteraction (心腎不交), and Dual Deficiency of Heart and Spleen (心脾兩虛); 4 disease locations, including liver (肝), heart (心), spleen (脾), and kidney (腎); and 3 disease natures, including Yin Deficiency (陰虛), Qi Stagnation (氣滯), and Blood Deficiency (血虛). In addition, we added 3 supplemental disease natures, including Yang Deficiency (陽虛), Qi Deficiency (氣虛), and Heat (火熱), in consideration of syndrome differentiation categories that may possibly be added in a follow-up clinical questionnaire. Conclusions: This resulted in a total of 7 differentiated syndromes, 4 disease locations, and 6 disease natures. We translated the clinical symptoms of these 17 categories into Korean Hangeul. After consulting with 5 Oriental medicine experts and a psychology expert, we produced a questionnaire for use in diagnosing menopause based on syndrome differentiation. The calculation of scores for the syndrome differentiation screening tool will be confirmed through clinical research based on the results of a review of existing literature.

Study on Establishment of criteria for Heart Disease in Oriental Medicine (심병증 진단요건의 표준 설정을 위한 연구)

  • Choi Sun Mi;Park Kyung Mo;Jeung Chan Gil;Sung Hyun Jea;Ahn Kyoo Seok
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.17 no.4
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    • pp.845-851
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    • 2003
  • The objective is to establish the standard of criteria for differential diagnosis of signs and symptoms. This study selected signs and symptoms related to heart which stands for Fire(火) as a kind of five phase(五行). Eleven experts was asked to evaluate the adequateness of criteria which was developed by Korea Institute of Oriental Medicine(KIOM) and to suggest the amendment of them. To implement the study, we used the questionnaire which asks about the diagnosis criteria for an insufficiency of the heart-qi(心氣虛證), deficiency of the heart blood(心血氣證), deficiency of the heart-yin(心陰虛證), insufficiency of the heart-yang(心陽虛證), exuberant fire due to hyperactivity of the heart(心火亢盛證), stagnation of the heart blood(心血瘀阻證), heart disturbed by phlegm-fire(痰火擾心證), attack of the heart by retainedfluid(水氣凌心證). Every criteria consists of primary symptoms, secondary symptoms, tongue findings. and pulse findings. In perspectives of the classification of patterns for signs and symptoms and criteria for diagnosis, the result shows that the previous standard doesn't have so many problem. So many of experts were agree with the criteria which was suggested but the trend is that they use, in their actual practice, less than the criteria. Additionally, they pointed that every element in a criterion should have the different weight value, criteria for the overlapped pattern should be added, and, in future, criteria which are based on clinical investigation should be established.

Study on Diseases Scope of Prescriptions Related with the Palpitation in "Shanghanlun" ("상한론"에 나타난 계(悸)와 관련된 처방들의 현대 질환 범위 고찰)

  • Park, Mi Sun;Kim, Yeong Mok
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.29 no.1
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    • pp.1-10
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    • 2015
  • This article is a study on palpitation of which disease cause, disease mechanism and formulas were analyzed with reference to annotations on "Shanghanlun" and "Jinkuiyaolue". And the scope of modern diseases related with palpitation was drawn by research on clinical papers. The source books are "Zhujieshanghanlun" and "Jinkuiyaoluefanglun" and the clinical papers are searched in China Academic Journals(CAJ) of China National Knowledge Infrastructure(CNKI). 13 clauses in "Shanghanlun" and 9 clauses in "Jinkuiyaolue" and 12 formulas are related with palpitation. Disease mechanisms of palpitation were classified as yang deficiency, yin deficiency, qi deficiency, blood deficiency, retained fluid, cold, etc and these days, qi stagnation, phlegm turbidity, blood stasis and fire heat are also considered as disease mechanisms. Modern diseases related with palpitation are arrhythmia(extrasystole, atrial fibrillation, bradycardia, tachycardia, sick sinus syndrome, atrioventricular block), vascular diseases(arterial occlusion, phlebothrombosis, Buerger's disease, coronary artery disease, vasculitis), blood pressure disorder(hypertension, hypotension) and heart diseases such as heart failure, angina pectoris, myocardial infarction, myocarditis, cardiomyopathy, pericardial effusion. And diseases related with psychological change(cardiac neurosis, anxiety neurosis, neurosis, depression, hyperthyroidism, hypothyroidism), pyrexia, anemia, drug intoxication, etc are also related with palpitation. Zhen Wu Tang showing an efficacy in dilating blood vessels and strengthening cardiac function, Wuling Powder with diuretic effect and Fried Glycyrrhizae Decoction acting on the ${\beta}$ receptor are applied to heart failure in different ways. Fried Glycyrrhizae Decoction(308 cases), Zhen Wu Tang(154), Wuling Powder(54), Xiao Chaihu Tang(34), Sini San(20) are reported to have been clinically applied to cardiovascular diseases and Zhen Wu Tang and Wuling Powder mainly applied to heart failure, Fried Glycyrrhizae Decoction, Lizhong Wan, Sini San and Zhen Wu Tang chiefly applied to arrhythmia related diseases. This study focuses on the general research and consideration on clinical applications and is a preliminary study to understand relations between Korean Medicine's symptoms and categories of modern diseases.

Analysis of mixed convective laminar flow and heat transfer about a sphere (혼합대류에 의한 구 주위의 충류유동 및 열전달 해석)

  • 이준식;김택영
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.11 no.2
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    • pp.345-353
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    • 1987
  • An analysis is performed to study flow and heat transfer characteristics of mixed free and forced convection about a sphere. Nonsimilar boundary layer equations which are valid over the entire regime of mixed convection are derived in terms of the mixed convection parameter, Gr/Re$^{2}$, through a dimensional analysis. The transformed conservation equations are solved by a finite difference method for the whole range of mixed convection regime. Numerical results for fluids having the Prandtl number 0.7 and 7 are presented. As the mixed convection parameter increases, the local friction coefficient and local heat transfer coefficient increases as well. For small Prandtl number, the friction coefficient is larger, while for large Prandtl number, the heat transfer coefficient is larger. Natural convection effect on the forced flow is more sensitive for small Prandtl number fluid. Flow separation migrates rearward as an increase in the mixed convection parameter. For small Prandtl number, the buoyancy effect is relatively small so that the flow separation occurs earlier.

Heat/Mass Transfer Characteristics on Stationary Turbine Blade and Shroud in a Low Speed Annular Cascade (I) - Near-tip Blade Surface - (환형 캐스케이드 내 고정된 터빈 블레이드 및 슈라우드에서의 열/물질전달 특성 (I) - 블레이드 끝단 인접 표면 -)

  • Rhee Dong-Ho;Cho Hyung Hee
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.4 s.235
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    • pp.485-494
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    • 2005
  • For the extensive investigation of local heat/mass transfer on the near-tip surface of turbine blade, experiments were conducted in a low speed stationary annular cascade. The turbine test section has a single stage composed of sixteen guide vanes and blades. The chord length and the height of the tested blade are 150 mm and about 125 mm, respectively. The blade has flat tip geometry and the mean tip clearance is about $2.5{\%}$ of the blade chord. Detailed mass transfer coefficient on the blade near-tip surface was obtained using a naphthalene sublimation technique. The inlet flow Reynolds number based on chord length and incoming flow velocity is changed from $1.0{\times}10^{5}\;to\;2.3{\times}10^{5}.$ Extremely complex heat transfer characteristics are observed on the blade surface due, to complicated flow patterns, such as flow acceleration, laminarization, transition, separation bubble and tip leakage flow. Especially, the suction side surface of the blade has higher heat/mass transfer coefficients and more complex distribution than the pressure side surface, which is related to the leakage flow. For all the tested Reynolds numbers, the heat/mass transfer characteristics on the turbine blade are the similar. The overall averaged $Sh_{c}$ values are proportional to $Re_{c}^{0.5}$ on the stagnation region and the laminar flow region such as the pressure side surface. However, since the flow is fully turbulent in the near-tip region, the heat/mass transfer coefficients are proportional to $Re_{c}^{0.8}.$

Seasonal Variation of Dissolved Methane Concentration and Flux in the Nakdong Estuary (낙동강 하구의 용존 메탄 분포와 메탄 플럭스의 계절변화)

  • RYU, JEHEE;AN, SOONMO
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.21 no.3
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    • pp.91-102
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    • 2016
  • The spatio-temporal variations of the dissolved methane concentration were investigated and the methane budget was estimated in the Nakdong Estuary in January, September, and November of 2014. Dissolved methane showed seasonal variation (21~874 nM) with high concentration in summer due to enhanced temperature and fresh water discharge. Decreasing trends of dissolved methane from the river to the estuary were consistent in all seasons showing the main source of the estuarine methane is river discharge. However, the decreasing trends were modified seasonally due to the local sources such as organic-rich sediments in intertidal zone or near the estuarine barrage. Dissolved methane concentration in the Nakdong Estuary was high, compared to other estuaries probably due to the well developed wetland in Nakdong-river system and stagnation effect from barrages and dams. Dominant sink for the Nakdong estuarine methane was outflux into the atmosphere. Relatively long residence time (produced by barrier island and estuarine dam) in the estuary might provide the enough time for the outgassing.