• 제목/요약/키워드: internal shapes

검색결과 280건 처리시간 0.026초

Internal Flow Characteristics of a Francis Hydro Turbine Model by Internal Flow Passage Shapes

  • Chen, Zhenmu;Wei, Qingsheng;Singh, Patrick Mark;Choi, Young-Do
    • 한국유체기계학회 논문집
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    • 제18권5호
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    • pp.19-25
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    • 2015
  • As a core component of a hydropower station, hydro turbines play a vital role in the integration of a power station. Research on the technology of hydro turbine is continuously increasing with the development of water electricity. On the basis of one-dimensional loss analysis, for three-dimension design, there are a lot of dimension of the internal flow passage shapes that are determined by experience. Therefore, the effect of the internal flow passage shapes on the performance and internal flow characteristics of a Francis hydro turbine model is investigated in this study. In this study, the small curvature of runner blade trailing edge shape is good for improving the efficiency of Francis turbine. The straight stay vane leading edge is good for suppressing the secondary flow. Moreover, suitable tongue passage shape and stay vane number improve the performance of the turbine considerably.

목재(木材) 건조중(乾燥中) 내부수분경사(內部水分傾斜)에 관(關)한 연구(硏究) (A Study on Internal Moisture Gradients of Wood)

  • 강호양
    • Journal of the Korean Wood Science and Technology
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    • 제19권2호
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    • pp.30-39
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    • 1991
  • Internal moisture gradients of 3cm-thick radiata pine (Pinus radiata) sapwood and meranti(Shorea spp.) heartwood were determined by using slicing method during drying and were predicted by Hart's Sorption Simulation. The shapes of internal moisture gradients. moisture contents and drying rates, which were obtained by the slicing method. were compared with those predicted by Sorption Simulation. After the 2nd fitting attempts. the differences between the gravimetric drying rates and the drying rates predicted by Sorption Simulation were less than 0.021%/hr for radiata pine and 0.043%/hr for meranti. The shapes of the internal moisture gradients predicted by Sorption Simulation were in good agreement with those obtained by the slicing method. It could be concluded that Sorption Simulation be an excellent tool to predict internal moisture gradients of wood.

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체적제어에 의한 적층 복합재 구멍의 형상 최적화 (Shape Optimization of Cutouts in a Laminated Composite Plate Using Volume Control)

  • 한석영;마영준
    • 대한기계학회논문집A
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    • 제28권9호
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    • pp.1337-1343
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    • 2004
  • Shape optimization was performed to obtain a precise shape of cutouts including the internal shape of cutouts in a laminated composite plate by three dimensional modeling using solid element. Volume control of the growth-strain method was implemented and the distributed parameter chosen as Tsai-Hill fracture index for shape optimization. It makes Tsai-Hill failure index at each element uniform in laminated composites under the predetermined volume a designer requires. Shapes optimized by Tsai-Hill failure index were compared with those of the initial shapes for the various load conditions and cutouts. The following conclusions were obtained in this study; (1) It was found that growth-strain method was applied efficiently to shape optimization of three dimensional cutouts in a laminate composite, (2) The optimal shapes of the various load conditions and cutouts were obtained, (3) The maximum Tsai-Hill failure indices of the optimal shapes were remarkably reduced comparing with those of the initial shapes.

내상병에 대한 형상의학적 치료 -위질환을 중심으로 (Treatment on Internal Damage Disease in Hyungsang Medicine)

  • 강영화;김형규;김경철;이용태
    • 동의생리병리학회지
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    • 제16권4호
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    • pp.657-666
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    • 2002
  • Review on internal damage disease(disease of the spleen and stomach) in Hyungsang medicine is as follows; In case of woman, Disease of the spleen and stomach is caused mostly a excessive thought. In case of man, Disease of the spleen and stomach is related to the genitals's disease for man is based on the kidney and body. In shapes of the Jung(精), Ki(氣). Shin(神) and Hyul(血), the seven feelings(emotions) in the Ki(氣) and Shin(神) types and deficiency of essence and blood in the Jung(精) and Hyul(血) types induce mostly diseases of the spleen and stomach. Treatments are used frequently to promote the normal flow of Ki(行氣), promote digestion and remove food stagnancy(消導), resolve phlem(化痰) and check upward perverted flow of fire(降火) in the Ki(氣) and Shin(神) types and tonity the essence(補精), tonity the blood(補血) and replenish Ki(補氣) in the Jung(精) and Hyul(血) types. The main parts to appear outside diseases of the spleen and stomach are face color, depression condition of eyes, lips' condition, LU10(魚際)'s color and the rise and fall of flesh etc. Shapes of the six meridians have to treat to divid shapes and symtoms of the six meridians according to 'deviation of Ki and blood' and 'the expression part of symtoms'.

타원 1-인벌루트-타원 2 형상을 조합한 새로운 형 제로터 개발 (Development of a New Gerotor for Oil Pumps with Multiple Profiles(Ellipse1, Involute and Ellipse2))

  • 정성윤;김문생;김철
    • 한국정밀공학회지
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    • 제28권5호
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    • pp.614-622
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    • 2011
  • An internal lobe pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. In particular, the pump is an essential machine element of an automotive engine to feed lubricant oil. The subject of this paper is the theoretical analysis of internal lobe pump whose the main components are the rotors: usually the outer one is characterized by lobe with multiple profile(ellipse1, involute and ellipse2) shapes, while the inner rotor profile is determined as conjugate to the other. Also, the design of outer rotor depends on new applications with removing carryover phenomenon. The system generates new lobe profile and calculates automatically the flow rate and flow rate irregularity according to the lobe profile generated. In order to obtain rotor shapes in performance and to find optimize the design parameters, a Taguchi method is proposed in this paper. Results obtained from the analysis enable the designer and manufacturer of oil pump to be more efficient in this field.

삼차원 적층복합재 구멍의 형상 최적화 (Shape Optimization of Three-Dimensional Cutouts in Laminated Composite Plates)

  • 한석영;마영준
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2004년도 춘계학술대회 논문집
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    • pp.275-280
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    • 2004
  • Shape optimization was performed to obtain the precise shape of cutouts including the internal shape of cutouts in laminated composite plates by three dimensional modeling using solid element. The volume control of the growth-strain method was implemented and the distributed parameter chosen as Tsai-Hill fracture index for shape optimization. The volume control of the growth-strain method makes Tsai-Hill failure index at each element uniform in laminated composites under the initial volume. Then shapes optimized by Tsai-Hill failure index were compared with those of the initial shapes for the various load conditions and cutouts. The following conclusions were obtained in this study. (1) It was found that growth-strain method was applied efficiently to shape optimization of three dimensional cutouts in a laminate composite, (2) The optimal shapes of the various load conditions and cutouts were obtained, (3) The maximum Tsal-Hill failure index was reduced up to 67% when shape optimization was peformed under the initial volume by volume control of growth-strain method.

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임의 형상의 여러 원자재 위에서의 효과적인 배치방안 (An Effective Method for the Nesting on Several Irregular Raw Sheets)

  • 조경호;이건우
    • 대한기계학회논문집
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    • 제19권8호
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    • pp.1854-1868
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    • 1995
  • An effective nesting algorithm has been proposed to allocate the arbitrary shapes on one or several raw sheets by applying the well-known simulated annealing algorithm as the optimization technique. In this approach, both the shapes to be allocated and the raw sheets are represented as the grid-based models. This algorithm can accommodate every possible situations encountered in cutting apparel parts from the raw leather sheets. In other words, the usage of the internal hole of a shape for other small shapes, handling of the irregular boundaries and the interior defects of the raw sheets, and the simultaneous allocation on more than one raw sheets have been tackled on successfully in this study. Several computational experiments are presented to verify the robustness of the proposed algorithm.

이화학적 살균제로 처리한 Campylobacter jejuni의 세포 형타와 미세구조에 대한 전자현미경적 연구 (Electron Microscopic Studies on the Morphology and Ultrastructures in Campylobacter jejuni treated with Physico-chemical Disinfectants)

  • 윤만석;오학식;김치경
    • Applied Microscopy
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    • 제19권2호
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    • pp.17-26
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    • 1989
  • The cells of Campylobacter jejuni treated with physical or chemical disinfection agents were comparatively examined by scanning and transmission electron microscopies for their morphological features and internal ultrastructures. The normal cells of C. jejuni, showed typical spiral rod shapes. The ribosomes, nucleoids, and other cellular constituents were observed to be distributed evenly throughout the cytoplasm. The cells treated with heat or UV-light were changed to spherical or irregular shapes and their cell envelopes were destroyed to form ghost cells by liberating their cytoplasmic components. The cells treated with chlorine or monochloramine were also changed into irregular round shapes. The chlorinated cells showed very rough surface structures with many blob-like protrusions, while the surface of the monochloramine-treated cells appeared to be relatively smooth.

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5부위 측정에 의한 사체형과 소증(素證)의 연관성에 대한 분석연구 (The Relevance Analysis between 4 Body Type through 5 Part Measuring and Ordinary Symptoms)

  • 최용석;문구;백동기
    • 대한한방내과학회지
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    • 제33권4호
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    • pp.558-571
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    • 2012
  • Objectives : The purpose of this study was to verify the difference in diet, digestion, sweat, feces and urination characteristics according to body shape characteristic. Methods : 1,302 participants were divided into 4 body types and were assessed through the questionnaire about Sasang constitution's ordinary symptoms such as diet, digestion, sweat, feces and urination characteristics. Results : Hyeong-keum type had active characteristics in the size of their meal and speed of taking meal. Hyeong-keum type got the most in the amount of sweating. And Yo-wi type reported the greatest urinary frequency. Conclusions : The difference of body type influences Sasang constitution's ordinary symptoms such as diet, sweat and urination. In digestion and feces, there was no statistical significance in the difference.