• The Journal of Korean Medicine
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• v.26 no.1 s.61
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• pp.71-75
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• 2005

There are wide variations in the definition and functions of tri-jiao among investigators in the area of Chinese medicine. Given a wide spectrum of views, it is difficult to identify uniform opinions about the definition and functions of tri-jiao. This paper is intended to clarify the meaning of the tri-jiao, which was presented as 'it builds a waterway and serves as the passage for the flow of Shuidao' in ${\ulcorner}\;SuWen\;\cdot\;Linglanbidianlun\;{\lrcorner}$ a classic text of traditional Chinese medicine. Investigators have been divided in their opinions in interpreting this reference; some claim that tri-jiao regulates fluid metabolism in the entire body while others assert that the role of tri-jiao is limited to lower-jiao that controls urination function. However, this does not appear convincing given the description in other texts of ${\ulcorner}\;SuWen\;\cdot\;Linglanbidianlun\;{\lrcorner}$, in which functions of 12 organs were explained in a summarized manner. The assumption that the role of tri-jiao is closely linked with lower-jiao seems to have deviated from the meaning of the original texts. Besides, fluid metabolism involves the entire body, and any pathological changes caused by disorders of fluid metabolism can affect any part of the body, not only the lower area of the body cavity. The phrase, 'passage for the flow of Shuidao,' expressed in the texts of ${\ulcorner}\;SuWen\;\cdot\;Linglanbidianlun\;{\lrcorner}$ is likely to mean that body fluid is also distributed and transported to the whole body along with primordial-Qi via tri-jiao. The phrase, 'passage for the flow of Shuidao' means that tri-jiao is involved in regulating body fluid metabolism and that it plays an important role in fluid distribution.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.3
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• pp.392-404
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• 1997

The flow induced by the oscillatory motion of a solid body is important in a number of practical problems. As the solid boundary oscillates harmonically, there is steady streaming motion invoked by the Reynolds stresses, which could cause extensive migration of the fluid during a period of fluid motion. We here analyzed the flow in a square cavity with an oscillating top wall for the parameters which make the time derivatives and the convective terms equally important in the entire cavity flow. The full Navier-Stokes equations are solved by the second-order time accurate Momentum Coupling Method which is devised by the authors. The particular numerical scheme does not need subiteration at each time step which is usually a required process to calculate the incompressible Navier-Stokes equations. The effect of two parameters, the Reynolds number and the frequency parameter, on the oscillatory flow has been investigated.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.817-832
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• 2021

In this paper, a simple practical method to estimate the drag of Super-Cavitating Underwater Vehicles (SCUV) is proposed that can obtain the drag with only principal dimensions in an initial design stage. SCUV is divided into cavitator, forebody, afterbody, base, and control fin and the drag of each part is estimated. The formulas for the drag coefficient are proposed for the disk and cone type cavitators and wedges used as control fins. The formulas are a function of cavitation number, cone or wedge angle, and Reynolds number. This method can confirm the drag characteristics of SCUV that the drag hump appears according to the coverage of the body by the cavity and the cavitator drag remains only when the entire body is covered by cavity. Applying this method to SCUV of various shapes, it is confirmed that the effects of cavitating and non-cavitating conditions, cavitator and body shape, and speed could be found.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.5
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• pp.451-457
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• 2006

Conjugate heat transfer (CHT) is the simultaneous, coupled heat transfer within a fluid and an adjoining solid, and the interface treatment plays an important role in its analysis, particularly when using unstructured grid system. In the present paper a new solid-fluid interface treatment in CHT analysis is presented and applied to two typical CHT problems, i.e. natural convections in both concentric thick-walled cylinders and cavity with a centered solid body. The present interface treatment for unstructured mesh clearly demonstrates the same accuracy and robustness as that for typical structured mesh.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.3
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• pp.373-384
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• 1989

The motions of a spinning rotor and a fluid enclosed in its cavity are known to have mutual interactions, which change the frequencies of forced vibrations and cause instabilities. These phenomena are of technical importance for fluid-cooled turbines as well as spin-stabilized satellites or rockets containing liquid fuels. In this paper the characteristics of unstable whirling of a rotor containing a partitioned cavity filled with two kinds of liquids are investigated experimentally. It studies the influence of rotational speed and filling ratio of two kinds of liquids on unstable whiring. As a result, it is found that the whirl velocity is approximately equal to, or slightly lower for large masses of trapped fluid than rotor critical speed. In case of a spinning rotor partially filled with two kinds of liquids the boundary surface plays a similar role to the free surface, and cases unstable forward whirl.

• The Korean Journal of Cytopathology
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• v.8 no.1
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• pp.35-46
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• 1997

The authors reviewed 167 malignant effusions from 110 patients, of which the primary site was established on the basis of either biopsy or surgical resection of the primary neoplasm. Main factors analysed were the distribution of primary organs and the cytohistoiogic correlation of body cavity effusions. The 167 fluid specimens from 110 patients consisted of 90 cases(53.9%) of pleural, 68(40.7%) of peritoneal, and 9(5.4%) of pericardial origins. Histologically they consisted of 82 cases(74.5%) of adenocarcinoma, 8(7.3%) of malignant lymphoma, 6(5.5%) of squamous ceil carcinoma, and 3(2.7%) of small cell carcinoma. The most common site among the primary lesions was the stomach in 25 cases(22.7%) followed by the lung in 21(19.1%), ovary on 17(15.5%), and breast in 7(6.4%). As for the distribution of primary tumors in adenocarcinoma, the most common site was lung un 16 cases (48.5%) in pleural fluid and stomach in 22(48.9%) in peritoneal fluid. In pericardial effusions, all 5 cases were from the lung. As a whole, the cytologic findings of malignant effusion were fairly representative of histologic characteristics of primary lesions. Thus, when the primary lesion Is unknown, careful evaluation of effusion cytology is presumed to be a helpful tooi for tracing the primary tumor.

• The KSFM Journal of Fluid Machinery
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• v.17 no.6
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• pp.59-63
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• 2014

Object of this study is to see whether the arc-groove on a D-shape bluff body effects the drag reduction or not. To this end, the changes of the boundary layer on the surface of the object, the downstream flow field and wake flow were found by experiments. The experiments are conducted by changing number and depth of the groove, angle of the first groove and Reynolds number(Re). Groove did not effect on the surface in the downstream boundary layer of the object and was minimal impact on the time mean velocity recovery of the wake flow. Also the effects of Groove did not have a significant impact on the structure of the wake and the wake frequency. Therefore it is found that the arc-groove of the drag reduction effect on the D-shape bluff body was smaller.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.51 no.10
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• pp.477-482
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• 2002

One of the key technologic requirements for rotary blood pumps is the sealing of the motor shaft. A mechanical seal, a journal bearing, magnetic coupling, and magnetic suspension have been developed, but they have drawbacks such as wear, thrombus formation, and power consumption. A magnetic fluid seal is durable, simple, and non power consumptive. Long-term experiments confirmed these advantages. The seal body was composed of a Nd-Fe-B magnet and two pole pieces; the seal was formed by injecting magnetic fluid into the gap (50${\mu}m$) between the pole pieces and the motor shaft. To contain the ferro-fluid in the seal and to minimize the possibility of magnetic fluid making contact with blood, a shield with a small cavity was attached to the pole piece. While submerged in blood, the sealing pressure of the seal was measured and found to be 31kPa with magnetic fluid LS-40 (saturated magnetization, 24.3 KA/m) at a motor speed of 10,000 rpm and 53kPa under static conditions(0mmHg). The specially designed magnetic fluid seal for keeping liquids out is useful for axial flow blood pumps. The magnetic fluid seal was incorporated into an intra-cardiac axial flow blood pump.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.3 s.153
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• pp.228-237
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• 2007

The flow characteristics around a horn-type rudder behind an operating propeller of a high-speed large container carrier are studied through a numerical method in fully wetted and cavitating flow conditions. The computations are carried out in a small scale ratio of 10.00(gap space=5mm) to consider the gap effects. The Reynolds averaged Navier-Stokes equation for a mixed fluid and vapor transport equation applying cavitation model are solved. The axisymmetry body-force distribution technique is utilized to simulate the flow behind an operating propeller. The gap flow, the three-dimensional flow separation, and the cavitation are the flow characteristics of a horn-type rudder. The pattern of three-dimensional flow separation is analyzed utilizing a topological rule. The various cavity positions predicted by CFD were shown to be very similar to rudder erosion positions in real ship rudder. The effect of a preventing cavitation device, a horizontal guide plate, is also investigated.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.06a
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• pp.93-98
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• 2006

Warm forming technology was classified into hot gas forming of using compressible fluid as a nitrogen gas and warm hydroforming of using the incompressible fluid as a thermal oil by using medium fluid. In this study, the aluminum side-rail part was developed with warm hydroforming technology. For the warm hydroforming system, top and bottom die was designed to insert heating cartridge in die cavity and special indirect fluid heating system was designed to heat the thermal oil. As increase the temperature, hydroformability was increased linearly. Aluminum side-rail center part was formed 90% at the internal pressure of 100bar and perfectly formed at 300bar within a moderate temperature. The tube material used for warm hydroforming was a aluminum 6000 series alloy with the diameter of 120mm, thickness of 5mm, length of 1,300mm. Warm hydroformed side-rail center part had 20% of maximum expansion ratio and below 20% of maximum thinning ratio at corner radius. This results were provided to show warm hydroforming possibility for aluminum automotive components.