• 대한기계학회논문집
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• 제18권6호
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• pp.1430-1438
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• 1994

Friction-factors for honeycomb surfaces are measured with a flat plate tester. The flat plate test apparatus is described and method is discussed for determining the friction-factor experimentally. The friction-factor is calculated for the flat plate test based on the Fanno-line flow. The test parameters are honeycomb cell width, depth, clearance, inlet pressure, and Reynolds number(or Mach number). A new empirical friction-factor model for honeycomb surfaces are developed as a function of these parameters.

• 한국전산유체공학회지
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• 제15권4호
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• pp.53-59
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• 2010

Preliminary design of a ground plate, a device installed close to the aircraft model for wind tunnel test to simulate the ground effect, was performed by a numerical simulation. A two-dimensional numerical study was performed initially to decide the optimal leading edge and flap configurations. Then, three-dimensional studies were conducted to decide the optimal flap deflection angle for pressure distribution reduction since the plate and the plate supporting system generate static pressure difference between the upper and lower flow regions. Three-dimensional simulation additionally studied the effect of the clearance between the plate and the wind tunnel side wall. For the efficiency of computation, half model was simulated and a symmetric boundary condition was applied on the center plane. Based on the preliminary design, a ground plate was designed, manufactured and tested at the Korea Aerospace Research Institute(KARI) wind tunnel. The measured pressure differences versus flap deflection angle agreed well with the predicted results.

• 대한후두음성언어의학회지
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• 제18권2호
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• pp.102-107
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• 2007

Laryngopharyngeal reflux disease (LPRD) is the result of retrograde flow of gastric contents to the laryngopharynx. Laryngoscopic findings and special questionnaires are first step of diagnosis of LPRD. Empiric trials of Proton pump inhibitor' test (PPI test) is recommended as treatment and diagnosis. However confirmation of reflux is then recommended primarily in patients with persistent symptoms despite acid-suppressive therapy. The 24 hour ambulatory double pH monitoring has been a gold standard method in diagnosis of LPRD even though it has some limitation. The combined multichannel intraluminal impedance and pH monitoring is a new-rising test tool. It can detect acid/non-acid, liquid/gaseous reflux and clearance of refluxate. The water siphon test is also used for diagnosis of LPRD.

• Design & Manufacturing
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• 제10권3호
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• pp.34-38
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• 2016

Roll forming is a continuous production process that is mass-produced. The roll forming process is produced in various forms. The special feature of roll forming is a continuous production. Therefore, the process of cutting the material is essential. The troubles in a shearing process affects the low productivity. Accordingly, it is important to reduce the factors that inhibit the material flow. And it is difficult to apply the common shear angle. Because it is not a simple forms, such as a progressive die. This study shows how to select the angle of a shear punch and the shape of a cutting punch in the product with a specific shape. Conclusively through three different model, it is advantageous to apply the different shear angle and clearance along the forms.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1058-1064
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• 2000

The analysis of dynamic behaviour of rotor system for the rolling piston type rotary compressor considering hydrodynamic force between motor rotor and stator is presented. In addition to considering other dynamic, loads such as large unbalance forces, gas force and bearing force, we consider the hydrodynamic force induced by the compressed fluid flow through the air gap between motor rotor and stator, and improve the analysis of vibration in rotary compressor. The Childs' method which based on Bulk-now and Hirs' turbulent lubrication model is used to calculate the rotordynamic coefficients due to hydrodynamic force of annular clearance in motor air gap.

• Biomolecules & Therapeutics
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• 제1권1호
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• pp.84-92
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• 1993

This study was performed to elucidate the mechanism of antidiuretic action of diltiazem by infusion into the vein and carotid artery, of diuretic action into a renal artery in dog. Renal denervation caused a reversal of the effect of diltiazem from the antidiuretic to the diuretic when infused into vein or carotid artery, and potentiated the diuretic effect when infused into a renal artery. The changes of renal function in diuretic circumstances as described above included the increase in renal plasma flow, osmolar clearance, the amounts of sodium and potassium excreted in urine and the decrease in reabosrption rate of sodium and potassium in renal tubules. Above results suggest that antidiuretic action of diltiazem may be mediated by central nervous system, not by endogenous substance, diuretic action by direct renal action.

• Journal of Chest Surgery
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• 제28권10호
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• pp.892-899
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• 1995

Pancreatitis is a known complication of cardiac surgery with cardiopulmonary bypass. Although ischemia is believed to be a factor, the exact cause of pancreatitis after cardiopulmonary bypass remains unknown.We prospectively studied 67 consecutive patients undergoing cardiac surgery with cardiopulmonary bypass for evaluation of the pancreatic injury after cardiopulmonary bypas. Serial measurement of amylase level in serum and urine was done postoperatively. Hyperamylasemia was detected in 15 patients[22.4% , of whom no patient had pancreatitis. There was no significant difference between serum amylase level and parameters such as cardiopulmonay bypass time, aortic cross clamp time, mean blood pressure, rectal temperature, flow rate, and use of circulatory arrest during cardiopulmonary bypass. Hyperamylasuria was detected in 8 patients[11.9% , and urine amylase level was elevated significantly in the groups with prolonged cardiopulmonary bypass, mean blood pressure more than 40mmHg, and rectal temperature more than 20 $^{\circ}$C. We recommend that serum amylase level and/or amylase-creatinine clearance ratio is measured for ealy detection and management of pancreatitis after cardiopulmonary bypass.

• 한국해양공학회지
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• 제18권5호
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• pp.1-6
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• 2004

This paper deals with the performance analysis and design of impulse turbine for owe type wave energy plant. Numerical analysis is performed using a commercial software FLUENT. This parametric study includes the variation of several important parameters, such as the number and shape of blades, hub ratio, and tip clearance. Since parametric study at various flow coefficients requires a considerable amount of computing time, two-dimensional analysis is employed to find out optimum principal particulars. Full three-dimensional calculations are also performed for several test cases, in order to confirm the validity of the two-dimensional approach. Up to the present stage, tentative results are demonstrated the usefulness of 2-D analysis.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.128-133
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• 2004

This study has been focused on the development of shear forming process of grid for lead-acid battery. The grid plays an important role in the flow of electricity because the grid is a skeleton of the pasted plate. Therefore, it must be of the highest quality to prevent plate failures and then, battery failure, and ensure the best battery performance possible. The finite element analysis of the shear forming process is carried out and the result is compared with the experimental data. The influence of the numerical parameters such as clearance, velocity of punch and critical damage value on the simulation results turns out to be very considerable.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제34회 추계학술대회 개최
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• pp.159-165
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• 2001

The fundamental fluid mechanics associated with the rotation of a smooth plane disk enclosed within a cylindrical chamber have been studied experimentally. In order to acquire systematic information pertinent to this problem torque and friction loss data were obtained over a wide range of disk Reynolds numbers for axial clearance-disk radius ratio H/R from 0.025 to 0.2 and radial tip gap-disk radius ratio s/R from 0.021 to 0.105. Loss analysis of hard disk drive(HDD) is presented to describe the contribution of windage loss of a rotating disk. The minimum loss from factor of HDD can be obtained from this analysis at each operation conditions.