• Tribology and Lubricants
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• 제25권6호
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• pp.409-413
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• 2009

This paper presents the hardness and friction characteristics of pb-free pin-bush bearing metal, which is manufactured by a centrifugal casting technology. A bronze metal with a high hardness and low friction properties is usually used for Diesel engine pin-bush bearing and high pressure cylinder. Pb-free metal for pin-bush bearings shows a little high hardness of 120 Hv compared with that of a conventional Pb bearing metal of 100~110 Hv. In general, the friction coefficient of pin-bush bearings is affected by a rotating speed and a load for various rubbing contact modes. But a contact load is more influential parameter when the contact rubbing mode transits from a mixed lubrication to a dry friction contact. The experimental result shows that the friction coefficient is more unstable at the dry contact mode compared with that of other two rubbing modes such as oil film contact and mixed friction conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.96-98
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• 2002

This paper proposes the digital pin line checker which can extremely improve the efficiency of the pine line checking using a micro processor. The line checker is designed which can check efficiently up to maximum 2048 pin. Alarm busser is designed ringing real-timely the case that the pin line is connected differently with real node number. Accordingly the comparing and identifying work visually the node number showing on the displaying board with real node number is avoided after the electronic stimulus enforce to the pin of the fixture by the test engineer. The digital line checker is designed based on the 8051. And the effectiveness and accuracy of the proposed line checking strategy is tested by simulating the several error connections for pin lines on the small scale board.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.7-12
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• 2004

Large-sized pins are usually used to lift and handle large low speed diesel engine crankshaft. There has then been a need to reduce and optimize the weight of the traditionally used pins. Making an hole by cutting the inside of the pin out was investigated in view of static and fracture strength. To compensate the stress increase caused by the introduction of the inner hole, the groove in the circumferential direction pre-existing on the pin is to be removed. Finite element analysis was carried out for both the original model and weight reduced model. Stress intensity factors for semi-elliptical defects assumed on the pin for the original model and weight reduced model was calculated using the ASME method and compared with the fracture toughness test result of the pin material. The diameter of the cutting hole for the revised model was determined based on the analysis results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2522-2525
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• 2001

Si PIN diodes are subject to be damaged from the exposure of fast neutron by displacement of Si lattice structure. The defects are effective recombination centers for carriers which migrate through the base region of the PIN diode when forward voltage is applied. It causes an increase in current and a decrease in resistivity of the diode. This paper presents the development of a neutron sensor based on displacement damage effect. PIN diodes having various structures were made bymicro-fabrication process, and neutron beam test was performed to identify neutron damage effect to the diode. From a result of the test, it was shown that the forward voltage drop of the diode, at a constant current, has good linearity for neutron dosage. Also it was found that the newton dosage can be measured by the pin diode neutron dosimeter with constant current power.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1436-1440
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• 1996

The wear mechanism of material is an important mechanic property to select a material's life and a optimum work condition. Although there are many researches about a wear mechanism of material, the pin-on-disc type tribotester is widely known to us. It is difficult to add a variable and heavy load in the existing pin-on-disc type tribotester to estimate this wear mechanism. And due to a rotation of a disc, it is impossible to add a constant force. But we can solve this problem by using a hydraulic servo system. Therefore, in order to investigate a wear mechanism of materials, it is necessary to design a hydraulic pin-on-disc type tribotester and construct a controller against a variable disturbance.

• 한국통신학회논문지
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• 제21권5호
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• pp.1304-1316
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• 1996

In this paper, A VCO(Voltage Controlled Oscillator) in use of clock recovery/data regeneration circuit for 10 Gbps fiber optic receivers was developed. The improved hair-pin resonator with a parallel coupled lines, which has been applied to microstrip filters, was used as a resonance part. As a frequcncy tuning device by substituting 3-terminalMESFET vaaractor for varactor diode, an MMIC manufacturing process will be simplified. Since a hair-pin resonator is planar type compared to the dielectric resonator and has a relatively flat reactance verus frequency, it will be favorable to apply a hair-pin resonator to an MMIC, in addition wideband frequency tuning range is able to be obtained.

• 산업기술연구
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• 제29권B호
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• pp.3-7
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• 2009

A cylindrical pin fin with inside fluid is optimized based on fixed fin volume by using the one dimensional analytic method. Heat loss from the fin and the pin fin radius for fixed fin volume is presented as a function of the fin length. Temperature variation of the fin with the variation of ambient and inside fluid convection characteristic numbers and fin base thickness is listed. The maximum heat loss at the practical fin length and corresponding optimum fin length and radius are presented as a function of fin base thickness, inside convection characteristic number, fin volume and ambient convection characteristic number. One of the results shows that the optimum pin fin shape becomes relatively fatter as the fin volume increases.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.899-902
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• 2003

Chip Pin Parasitic은 실제 Chip Pad에서부터 Bonding Wire를 통한 Package Lead Frame까지를 의미한다. 여기서, Lead Frame 및 Bonding Wire에서 Inductance 및 작은 저항이 보이고, Chip Pad에서의 Capacitance, 그리고 Pad 부터 Ground까지의 Return Path에서 발생하는 저항이 보인다. 이들을 모두 합하면 L, R, C의 Series로 나타낼 수 있다. 본 논문에서는 이런 Chip Pin Parasitic을 추출 하기 위해서 TDR(Time Domain Reflectometer)과 NA(Network Analyzer)를 사용하였는데, TDR의 경우 PCB를 제작하여 Chip을 Board위에 붙인 후 Time Domain에서 측정 하였고 NA의 경우 Pico Probe를 이용하여 Chip pin에 직접 Probing해서 Smith Chart를 통하여 Extraction 값을 추출했다. 이 경우, NA를 이용한 측정이 좀 더 정확한 Parasitic 값을 추출할 수 있으리라 예상되겠지만, 실제로 Chip이 구동하기 위해서는 Board위에 있을 때의 상황도 고려해야 하기 때문에 TDR 추출 값과 NA 추출 값을 모두 비교하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1630-1633
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• 2003

Hair pin bending machine is pipe forming machine consisting of heat exchanger product system. Hair pin produced by these machine is pathway of refrigerant and play a important role improving the performance and productivity of heat exchanger. The core technology of hair pin bending machine is forming the straight pipe into U-type without any defaults. Therefore, this paper study the relation between the pipe bending forming and the shape and position of mandrel using the elastic-plastic finite element analysis and provide a foundation technology for which developing the hair pin bending machine. The results are followed 1. Mandrel located in front of rotating center of bending die minimized the circular shape variation of copper pipe. 2. Diameter change of mandrel hardly effect the pipe shape.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.797-801
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• 2003

The mechanical properties such as shear strength and the hardness of milli-size products that manufactured for various process parameters by forward extrusion using square dies are investigated. Shear strength test is implemented for the observation of relation between vickers hardness and shear strength in the interface of head and shaft part of a stepped pin. When the extrusion ratios of pure aluminum and pure copper billets increase, the hardness on both the surface and the center line of a pin also increase, especially the hardness on the surface is shown to be a little higher than on the center. The existence of knock-out pad in extrusion die caused hardness increase in the interface of a extruded pin. As compared shear strength with hardness of a pin, the approximated linear relations are suggested in this study.