• 대한생식의학회:학술대회논문집
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• 2004.06a
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• pp.60.1-60.1
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• 2004

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.75-79
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• 1996

가공품 중에서 구멍가공이 차지하는 비율은 매우 높으며 또한 가공정밀도가 요구되어진다. 그러나구멍의 직경에 비하여 길이가 길어지면 칩의 배출, 절삭날부의 윤활이 어려워지고, 공구의 진동문제가있기 때문에 일반적인 가공으로는 불가능할 경우가 많다. 따라서 이에 적절한 가공방법은 고압력의 절삭유를 공급할 수 있는 공구를 이용하여 가공할 수 있으며, 그 대표적인 방법으로는 Spade Drill, Gun Drill, 및 BTA Dill에 의한 깊은구멍가공봅이다. 본 연구에서는 Single Tube BTA 드릴링 시스템에서 Single Edge BTA Drill을 사용 하여 깊은 구멍을 가공할 때 공작물 SM55C의 최적절삭 조건의 선정과 공구수명에 대하여 실험을 통하여 분석 하고자 하였다.

• Proceedings of the SAREK Conference
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• 2005.06a
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• pp.219-219
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• 2005

• Proceedings of the SAREK Conference
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• 2004.06a
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• pp.51-51
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• 2004

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.192-193
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• 2007

A hollow cathode which has extremely stable discharge characteristic has been developed. This is composed of the two separated lanthanum hexaboride ($LaB_6$) of a disk type in the tube as the electron emitters. The way of design is of great advantage to extend the surface discharge area of the $LaB_6$, which is also useful for optimal fixing of the $LaB_6$. The hollow cathode is capable of producing 30 kW (100 V, 300 A) of power continuously.

• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.2
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• pp.13-23
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• 1999

This paper deals with manufacturing process design of a simplified gun tube applying CE principle. A concept and characteristics of CE, mathematical model for understanding interaction between design and manufacturing, basic elements and related equations for process planning and cost estimating are introduced. A Knowledge-based Computer-Aided Process Planning System(KCAPPS) is constructed, yielding optimal production cost/time for the shape input and selection of appropriate machines and tools.

• The Journal of Dong Guk Oriental Medicine
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• v.8 no.2
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• pp.83-96
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• 2000

Objective This experimental study was designed to investigate effects of Sam-chool-gun-bi-tang administration during carbohydrate loading diet to long distance runners on changes of the urine metabolic responses. Materials and Methods All subjects were divided randomly with two groups, Sam-chool-gun- bi-tang administration Group (N=5) and control group (N=5) and attended on domestic marathon race. The urine samples were collected by 15ml conical tube at rest, a day before race, immediately after race, a day after race. These samples were used to analyze for the factors of the change on metabolic responses. At First, the factors of the routine urine test were checked; RBC, WBC, glucose, protein, ketone, bilirubin, urobilirubin. Next, the factors on the changes of the electrolyte metabolism and creatinine were checked; $Na^+ $, $Cl^-$, $K^+$, $Ca^{+ +}$, Creatinine. Results 1. Urine RBC, WBC, glucose, protein, ketone, bilirubin, urobilirubin were all denoted negatively (-). 2. Urine pH response in Sam-chool-gun-bi-tang administration group was shown significant difference between two groups at immediately after race. 3. Urine $Na^+$ response in Sam-chool-gun- bi-tang administration group was shown significant difference between two groups at immediately after race. 4. Urine $K^+$ response in Sam-chool-gun-bi-tang administration group was shown significant difference between two groups at immediately after race and a day after race. 5. Urine $Cl^-$ response in Sam-chool-gun- bi-tang administration group was increased at immediately after race, but was not shown significant difference between two groups. 6. Urine $Ca^{+ +}$ response in Sam-chool-gun-bi-tang administration group was decreased gradually, but was not shown significant difference between two groups. 7. Urine Creatinine response in Control group was decreased significantly at immediately after race, but was not shown significant difference between two groups. Conclusion According to the above results, it was shown that Sam-chool-gun- bi-tang administration had the positive effects on changes of the urine matabolic responses during carbohydrate loading diet to the long distance runners.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.263-266
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• 2007

The ballistic range has long been employed in a variety of engineering fields such as high-velocity impact engineering, projectile aerodynamics, creation of new materials since it can create an extremely high-pressure state in very short time. Two-stage light gas gun is being employed most extensively. The present experimental study has been conducted to develop a new type of ballistic range which can easily perform a projectile simulation. The experiment is conducted to find out the dependence of various parameters on the projectile velocity. The pressure in high-pressure tube, pressure of diaphragm rupture and projectile mass and piston mass are varied to obtain various projectile velocities. The flow field is visualized to see flow around projectile.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.177-180
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• 2010

Two-stage light gas gun, sorted with Ballistic Range System, is used to research spray characteristics of supersonic liquid jets. When high pressure tube was pressurized to the 135 bar, diaphragm films which composed with OHP film are ruptured. Expansion gases accelerate a projectile approximately 250 m/s at the exit of pump tube. And accelerated projectile collides with liquid storage part and liquid jets were injected into supersonic conditions. Supersonic liquid jets show the multiple jets and generate shockwave at the forward region of jets. Supersonic liquid jets of speed and shockwave angle have different value at each case. Supersonic liquid jets with minimum velocities are injected with M=1.53 at the geometry condition of L/d=23.8.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.3
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• pp.171-181
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• 2017

Two-phase cross flow exists in many shell-and-tube heat exchangers such as condensers, evaporators, and nuclear steam generators. The drag force acting on a tube bundle subjected to air/water flow is evaluated experimentally. The cylinders subjected to two-phase flow are arranged in a normal square array. The ratio of pitch to diameter is 1.35, and the diameter of the cylinder is 18 mm. The drag force along the flow direction on the tube bundles is measured to calculate the drag coefficient and the two-phase damping ratio. The two-phase damping ratios, given by the analytical model for a homogeneous two-phase flow, are compared with experimental results. The correlation factor between the frictional pressure drop and the hydraulic drag coefficient is determined from the experimental results. The factor is used to calculate the drag force analytically. It is found that with an increase in the mass flux, the drag force, and the drag coefficients are close to the results given by the homogeneous model. The result shows that the damping ratio can be calculated using the homogeneous model for bubbly flow of sufficiently large mass flux.