• 천문학회지
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• 제43권3호
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• pp.55-64
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• 2010

We investigate how plasma structures in the solar chromosphere and corona can extend to altitudes much above hydrostatic scale heights from the solar surface even under the force of gravity. Using a simple modified form of equation of motion in the vertical direction, we argue that there are two extreme ways of non-hydrostatic support: dynamical support and magnetic support. If the vertical acceleration is downward and its magnitude is a significant fraction of gravitational acceleration, non-hydrostatic support is dynamical in nature. Otherwise non-hydrostatic support is static, and magnetic support by horizontal magnetic fields is the only other possibility. We describe what kind of observations are needed in the clarification of the nature of non-hydrostatic support. Observations available so far seem to indicate that spicules in the quiet regions and dynamic fibrils in active regions are dynamically supported whereas the general chromosphere as well as prorninences is magnetically supported. Moreover, it appears that magnetic support is required for plasma in some coronal loops as well. We suspect that the identification of a coronal loop with a simple magnetic flux tube might be wrong in this regard.

• Journal of Mechanical Science and Technology
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• 제17권7호
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• pp.1104-1110
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• 2003

The present study investigates the hemorheological characteristics of blood flow with applying vibration to a non-aggregating red blood cell suspension. In order to obtain the non-aggregating RBC suspension, blood samples were treated with vibration at a specified condition, which viscosities were taken before and after the treatment, respectively. The viscosity of the blood samples after treatment was higher than before treatment. These treated blood samples were forced to flow through a capillary tube that was vibrated perpendicularly to the direction of the flow. The experimental results showed that vibration caused a reduction of the flow resistance of the non-aggregated blood. The reduction of the flow resistance was strongly dependent on both frequency and amplitude of vibration. These results show potential in treating various diseases in the microcirculation associated with blood cell aggregation.

• Journal of Advanced Marine Engineering and Technology
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• 제20권2호
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• pp.116-116
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• 1996

This paper is concerned with a method for calibrating five-hole probes of both angle-tube and prismatic geometries to measure local total and static pressures and the magnitude and direction of the mean velocity vector. Descriptions of the calibration technique, the typical calibration data, and an accompanying discussion of the interpolation procedure are included. The flow properties are determined explicitly from measured probe pressures using calibration data. Flow angles are obtained within the deviation angle of 1.0 degree and dynamic pressures within 0.03 with 95% certainty. The variations in the calibration data due to Reynolds number are also discussed. For the range of Reynolds number employed, no effect was detected on the pitch, yaw and total pressure coefficients. However, the static pressure coefficient showed change to cause minor variations in the magnitude of the calculated velocity vector. To account for these variations, average correction factors need to be incorporated into the static pressure coefficient.

• Journal of Advanced Marine Engineering and Technology
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• 제20권2호
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• pp.48-56
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• 1996

This paper is concerned with a method for calibrating five-hole probes of both angle-tube and prismatic geometries to measure local total and static pressures and the magnitude and direction of the mean velocity vector. Descriptions of the calibration technique, the typical calibration data, and an accompanying discussion of the interpolation procedure are included. The flow properties are determined explicitly from measured probe pressures using calibration data. Flow angles are obtained within the deviation angle of 1.0 degree and dynamic pressures within 0.03 with 95% certainty. The variations in the calibration data due to Reynolds number are also discussed. For the range of Reynolds number employed, no effect was detected on the pitch, yaw abd total pressure coefficients. However, the static pressure coefficient showed change to cause minor variations in the magnitude of the calculated velocity vector. To account for these variations, average correction factors need to be incorporated into the static pressure coefficient.

• 한국전기전자재료학회논문지
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• 제13권9호
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• pp.801-804
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• 2000

High-temperature superconductor of Bi-2212 system was fabricated by CFP(Centrifugal Forming Process). To make a uniform specimen slurry was prepared in the ratio of 7:3(powder : binder) and ball milled for 24 hours. Milled slurry was charged into a rotating mold with 450 rpm and dried at room temperature. Then the specimen was performed binder burn-out at 35$0^{\circ}C$ and heated for partial melting to 86$0^{\circ}C$. XRD analysis of most specimens were shown 2212 phase and observed a local plate shped microstructure with a well aligned c-axis direction from SEM images. Measured T$_{c}$(Critical temperature) was about 64 K.K.

• 대한기계학회논문집B
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• 제31권11호
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• pp.912-917
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• 2007

Regionally averaged heat transfer distributions and friction factors in square channels with twisted tape inserts and with twisted tape inserts plus interrupted ribs are experimentally investigated. The effects of surface heating condition on heat transfer enhancement are also investigated. Each wall of the square channel is composed of isolated aluminum plates. The interrupted square ribs are arranged along the axial flow direction on the bottom wall only. Experimental tests are performed for Reynolds numbers ranging from 8,900 to 29,000. The results are compared with those of previous investigations for circular tube with axial interrupted ribs and twisted tape inserts.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1995년도 춘계학술발표회 초록집
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• pp.223-229
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• 1995

Heat transfer phenomena during freezing process of the water in a vertical cylinder were experimentally studied. Purified water was inserted into the vertical cylinder Experiment was performed with two conditions ; the inlet temperature of the working fluid was maintained to be -1$0^{\circ}C$ and the direction of the working fluid was to be upward or downward. Both the mean temperature of the liquid and temperature difference of cylinder tube wall in the upward were lower than those in the downward. In addition, shape of ice layer in the upward was more uniform than that in the downward. Finally, time-varying total heat energy stored in the water in the upward was higher than that in the downward.

• KIEE International Transactions on Electrophysics and Applications
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• 제5C권5호
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• pp.204-210
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• 2005

Alternating current (AC) losses of two Bi-2223 ([Bi, Pb]: Sr: Ca: Cu: O = 2:2:2:3) tapes [(Tape I, un-twist-pitch) and the other with a twist-pitch of 10 mm (Tape II)] were measured and compared. These samples, produced by the powder-in-(Ag) tube (PIT) method, are multi-filamentary. Also, it's produced by non-twist and different twist pitch (8, 10, 13, 30, 50 and 70 mm). The critical current measurement was carried out under the environment in liquid Nitrogen and in zero-field by 4-probe method. Susceptibility measurements were conducted while cooling in a magnetic field. Flux loss measurements were conducted as a function of ramping rate, frequency and field direction. The AC flux loss increases as the twist-pitch of the tapes decreased, in agreement with the Norris Equation. Neutron-diffraction measurements have been carried out investigate the crystal structure, magnetic structures, and magnetic phase transitions in Bi-2223([Bi, Pb]:Sr:Ca:Cu:O)

• Animal cells and systems
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• 제4권3호
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• pp.201-214
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• 2000

Two quite different types of plant cells are analysed with regard to transduction of the gravity stimulus: (i) Unicellular rhizoids and protonemata of characean green algae; these are tube-like, tip-growing cells which respond to the direction of gravity. (ii) Columella cells located in the center of the root cap of higher plants; these cells (statocytes) perceive gravity. The two cell types contain heavy particles or organelles (sataoliths) which sediment in the field of gravity, thereby inducing the graviresponse. Both cell types were studied under microgravity conditions ($10^{-4}$/ g) in sounding rockets or spacelabs. From video microscopy of living Chara cells and different experiments with both cell types it was concluded that the position of statoliths depends on the balance of two forces, i.e. the gravitational force and the counteracting force mediated by actin microfilaments. The actomyosin system may be the missing link between the gravity-dependent movement of statoliths and the gravity receptor(s); it may also function as an amplifier.

• Elastomers and Composites
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• 제51권4호
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• pp.280-285
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• 2016

The purpose of this study is to get optimum design and operation conditions of the heating rubber roller for laminating process. The cause of performance degradation of heating rubber roller is delamination of rubber on metal tube, rubber aging due to high temperature. We measured the material properties of thermal expansion, thermal conductivity, specific heat and density and analyzed thermal distributions of rubber layer using finite element method. As a result of heat/flow analysis, the density distribution of heating coil must shorten the stabilization time by reducing the temperature deviation on the length direction at the temperature rising section after increasing the density of the area contacting with the laminate film at the center part which is an opposite of the current composition while enabling to maintain the temperature of heater to be consistent while maintaining the temperature deviation to be low when heat loss is created. Finally, we determined optimum heating method of heating rubber roller.