• 제목/요약/키워드: Clearances

검색결과 199건 처리시간 0.022초

복령의 이뇨작용 (Diuretic action of hoelen in the dog)

  • 이경일;고석태
    • 약학회지
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    • 제18권1호
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    • pp.39-48
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    • 1974
  • Intravenously administered total water extract of Hoelen, (Pachymae fungus) in a dose of 10mg/kg and its methanol lextract, in a smaller dose than total water extract, produced significantly increase on urinary volume, sodium nad potassium excretion, and osmolar nad free water clearances. Increasing the doses produced more pronounced renal responses. Glomerular filtration rate and renal plasma flow changed littl with both extract. On the contrary, water extract from residue obtained on extraction with organic solvents exhibited no significant changes on the parameters of the renal function. In experiments, in which the total water extract was infused directly into a renal artery and urines from both ureters were collected separetely, a small dose of 0.3mg/kg/min showed no diuresis, but a large dose of 1.0mg/kg/min elicited diuretic action even on the contralateral kindneys. It is, therfore, concluded that Hoelen induces diuresis, mainly by inhibiting reabsorption of electrolytes in the renal tubules, and that the renotropic action may be mediated by some endogenous humoral substances.

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충돌공기제트시스템에서 직삼각형로드에 의한 열전달특성 (Heat Transfer Characteristics by the Right Angled Triangle Rod Array in Impinging Air Jet System)

  • 금성민
    • 한국분무공학회지
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    • 제13권1호
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    • pp.9-15
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    • 2008
  • This experimental study was carried out to examine the heat transfer characteristics of impinging air jet on a flat plate with a set of right angled triangle rods. Each right angled triangle rod in the array was positioned normal to the flow direction and parallel to the flat plate surface. The clearances from a right angled triangle rod to flat plate surface (C=1, 2 and 4 mm) and the distance from nozzle exit to flat plate (H=100 and 500 mm) were changed for the pitch between each right angled triangle rods (P=40 mm). As a result, heat transfer shows best performance at the clearance of C=1 mm, in case clearance changed, and the average heat transfer enhancement rate increased up to 47% compared to the result of a flat plate without a right angled triangle rod.

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R134a 터보냉동기용 원심압축기의 익단간극이 성능특성에 미치는 영향에 관한 수치해석적 연구 (Numerical Study on Tip Clearance Effect on Performance Characteristics of a Centrifugal Compressor for a R134a Turbo-Chiller)

  • 이경용;최영석;박운진
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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    • pp.451-456
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    • 2003
  • In this study, the overall performance and the effect of the tip leakage flow of the centrifugal compressor with the refrigerant HFC-l34a were numerically studied using CFX-TASCflow. To study the effect of a tip leakage flow, the numerical study of the overall performance of HFC-l34a centrifugal compressor with a cascade diffuser was preceded and compared with experimental result. Six different tip clearances were used to consider the influence of a tip clearance on performance. The tip leakage flow was illustrated for qualitative discussion. The results obtained in this study can be applied to the determination of the cold clearance.

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Tip Clearance Losses - A Physical Based Scaling Method

  • Pelz, Peter F.;Karstadt, Sascha
    • International Journal of Fluid Machinery and Systems
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    • 제3권4호
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    • pp.279-284
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    • 2010
  • Tip clearance losses occur in every turbomachine. To estimate the losses in efficiency it is important to understand the mechanism of this secondary flow. Tip clearance losses are mainly caused by a spiral vortex formed on the suction side of the blade of a turbomachine, which induces a drag and also has an influence on the incident flow of the blades. In this paper a physical based scaling method is developed out of an analytical ansatz for the tip clearance losses. This scaling method is validated by measurements on an axial fan with five different tip clearances.

관류홴의 최대유량역에서 설계인자 변화에 따른 공력성능 특성에 관한 실험적 연구 (Experimental Study on the Aerodynamic Performance Characteristics for Various Design Factors in the Maximum Flowrate Range of a Cross-Flow Fan)

  • 김장권
    • 동력기계공학회지
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    • 제9권3호
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    • pp.44-49
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    • 2005
  • The aerodynamic performance of an indoor room air-conditioner using a cross-flow fan is strongly influenced by the various design factors of a rear-guider and a stabilizer. The purpose of this study is to investigate the effects of a rear-guider and a stabilizer on the aerodynamic performance in the maximum flowrate range of a cross-flow fan. The design factors considered in this study are a rear-guider clearance, a stabilizer cutoff clearance, and a stabilizer setup angle, respectively. Aerodynamic performances including maximum flowrate and power show the biggest magnitude distribution in the case of $45^{\circ}$, the stabilizer setup angle as well as nearly similar magnitude distribution regardless of the stabilizer cutoff clearances. Moreover, the more a rear-guider clearance increases, the more the magnitude of maximum flowrate and power increases.

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U-bending 공정에서 틈새간격이 샌드위치판재의 내부구조 전단변형에 미치는 영향 (Effect of The Clearance on Core Deformation of Sandwich Plate during U-bending)

  • 성대용;정창균;심도식;양동열;정완진
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2008년도 춘계학술대회 논문집
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    • pp.320-323
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    • 2008
  • In this study, a macroscopic approach was carried out to gain insight into the bending mechanism of metallic sandwich plates. Shear force-punch stroke curves for various clearances were analytically derived for mild steel (CSP 1N) sandwich plates with the total thickness of 3 mm and 0.5 mm face sheets. As the clearance increases, shear force of the inner structures and sensitivity of punch stroke decrease. These data are useful to derive a criterion of judgment for core shear failure and de-bonding failure during U-bending.

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수압 특성 연구를 기초로 한 수압시스템의 설계에 관한 연구 (A Study on the Design of water Hydraulic Systems Based on Characteristics of Tap-Water)

  • 윤영원;남윤주;박명관
    • 대한기계학회논문집B
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    • 제28권11호
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    • pp.1322-1331
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    • 2004
  • This paper presents studies on the design of water hydraulic system and components to replace oil with tap-water as the pressure transmission medium in hydraulic systems. In order to improve the performance of water hydraulic system, the thermal and hydraulic properties of tap-water are first investigated. Based on these characteristics, the design parameters, such as the clearances of the moving parts, the cross-sectional area of pipes and relative roughness, are proposed so that the performance of water hydraulic system is the same as that of oil. In addition, the operating ranges, which show the possibility of using water hydraulic system, are examined.

고무차륜형식 경전철(AGT) 대차의 구조해석 및 주파수 응답해석 (The Structural and Frequency Response Analysis for the Bogie of the Rubber Wheel-type AGT)

  • 변상윤;유형선;윤성호
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 1999년도 추계학술대회 논문집
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    • pp.558-565
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    • 1999
  • Rubber wheel-type AGT has two major kinds of bogie; one is the bogie type and the other and passenger loads. This paper deals with the statics analysis for two types of bogie frame subjected to combined external forces, as well as independent ones specified in UIC 515-4. Furthermore, the dynamics analysis is performed under vibrational loading conditions so as to compare dynamic characteristics, Numerical results by using commercial packages, Ⅰ-DEAS and NASTRAN show that maximum stresses do not exceed the yielding level of material used for both bogies. From an overall viewpoint of strength, the bogie type turns out to be superior to the steering type except the case of a lateral loading. It is also observed that the steering type shows a be stiffened. It is strongly anticipated that vibrational fatigue analysis should be carried out under realistic loading conditions closely matching to situations such as running surface and lateral clearances along the guideway.

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송전철탑 Compact화에 따른 전기환경 영향 연구 (A Study on the Environmental Effects of Compact Tower in Transmission Line)

  • 이정원;이원교;이동일
    • 한국전기전자재료학회논문지
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    • 제23권8호
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    • pp.645-650
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    • 2010
  • The continuous increase demand for electric power leads to the additional construction of transmission facilities, but it is not easy to acquire right-of-way for transmission facilities. Therefor, there is a need for compact tower that can be built on a narrow right-of-way the compact tower with polymer insulation arm is a solution. It can be upgrading conventional 154 kV transmission line voltages to 345 kV levels. However transmission voltage is increasing, environment interference (corona noise, radio interference, etc.) will occur gradually. This environment interference is depending on the electrical clearances of tower and configuration of conductors. Therefore the analysis of the factors of environmental interference is necessary in order to upgrading transmission voltage. This paper presents the design factor of a compact tower to meet the environmental interference standard.

토끼의 신장기능에 미치는 $K^+$ Channel 차단제인 Glibenclamide의 영향 (Effect of Glibenclamide, $K^+$ Channel Blocker, on Renal Function in Rabbit)

  • 고석태;나종학
    • Biomolecules & Therapeutics
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    • 제9권1호
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    • pp.26-32
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    • 2001
  • This study was investigated about the effect of glibenclamide (GLY) which is $K^{+}$ channel blocker on renal function in rabbit, GLY, when given into the vein, produced the diuretic action accompanied with the increases of amounts of N $a^{+}$ and $K^{+}$ excreted into urine ( $E_{Na}$ , $E^{K}$), and then osmolar and negative free water clearances ( $C_{osm}$, $T^{C}$$_{H2O}$), fraction excretory rates of filtered N $a^{+}$ and $K^{+}$ ( $F_{Na}$ , $F_{K}$) and ratios of $E_{K}$ against $E_{Na}$ were augmented. Filtration fraction (FF) were reduced because renal plasma flow (RPF) were not changed but glomerular filtration rates (GFR) were diminished. GLY administered into a renal artery exhibited significant reduction of urine volume along with the decreases of GFR and RPF in only experimented kidney whereas changes of renal function was not observed in control kidney. GLY given intracerebroventricularly exhibited diuretic action along with the increase of $E_{Na}$ , $E_{K}$ and $F_{Na}$ , $F_{K}$ by small dose which was not affect on renal function when it given into the vein. Above results suggest that GLY given into the vein in rabbit produce the diuretic action by inhibition of electrolytes reabsorption in renal tubules through central function. function.n. function.ion.

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