• Tribology and Lubricants
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• v.19 no.4
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• pp.223-229
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• 2003

The sliding wear characteristics of the crane sheave were investigated using a pin-on-disk rig tester. The experiment was conducted using a high carbon steel wire that was upper material, also carbon steel castings that was disk material. There are various operating conditions in this work. At the room temperature, we carried out the wear test under a grease lubrication and dry condition. The results of wear test showed that an annealed-casted have lower, also the wear curves are linearly increased with increasing of sliding distance. For the specific wear rate of annealed-casted, the wear resistance was increased with decreasing diameter of wire. The wear of a wire and a disk have a different mechanism, the one is the abrasive wear due to fatigue wear under lubrication, another is the adhesion wear under dry condition.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.221-224
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• 2001

In this paper, the bonding wire interconnection has been studied from the points of view of modeling and electrical characterization. The bonding wire is measured by TDR(Time Domain Reflectometry) and Network analyzer(1-10㎓). First, one gold bonding wire mounted on 2mm gap substrate measured 3.68nH by TDR and 3.39nH by Network analyzer(6㎓). Two gold bonding wire mounted on 2mm gap substrate measured 3.14nH by TDR and 2.80nH by Network analyzer. This result presented that inductance of bonding wire could be employed as inductors for radio frequency circuit packaging.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.11
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• pp.1873-1880
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• 2003

The sliding wear characteristics of the crane sheave were investigated using a pin on disk rig tester. The experiment was conducted using a high carbon steel wire that was upper material, also carbon steel castings that was disk material. There are various operating conditions in this work. At the room temperature, we carried out the wear test under a grease lubrication and dry condition. The results of wear test showed that an annealed-casted have lower, also the wear curves are linearly increased with increasing of sliding distance. For the specific wear rate of annealed-casted, the wear resistance was increased with decreasing diameter of wire. The wear of a wire and a disk have a different mechanism, the one is the abrasive wear due to fatigue wear under lubrication, another is the adhesion wear under dry condition.

• Journal of Aerospace System Engineering
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• v.5 no.1
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• pp.13-16
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• 2011

All components such as structure, engine, electrical equipment, wire etc. should have certified qualities and functions for safe flight. The wire like a blood vessel of man is connected with most components and supply a electrical signal or power to them and only certified wire through a lot of tests such as rating, flame resistance, self-extinguishing, protection of EMI etc. must be used in aircraft. In other words, the wire should observe many certification requirements because it is one of the most important components.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.10
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• pp.867-873
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• 2002

We have designed and fabricated the slidacs type automatic voltage regulator(SVR) that is able to control the output voltage continuously according to load variation. Especially, the frictions between the surface of contact of the slidacs coils and the output wire moving shaft arc reduced by modifying the mechanical configuration of surface of contact of slidacs from the conventional sliding one into the proposed rotary one composed of cylindrical bearing. Thus, SVR using cylindrical bearing proposed in this study has less noise than the conventional one owing to the reduction of friction, and its breakdown ratio caused by the abrasion of contact materials is reduced as well. We have designed U motor driving circuit for controlling the output wire moving shaft, and introduced the digital control method using the pulse width modulation(PWM) output for controlling DC motor.

• Proceedings of the KWS Conference
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• 2007.11a
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• pp.127-128
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• 2007

To investigate mechanical property on the low temperature plate weld metal, the two different plates of the same steel grade were welded and evaluated on the multiple pass welds and both side one run welds with different Mo contents welding consumables. The results are summarized as follows; 1) Welds made by no Mo containing wire showed very low impact values for type of material company. 2) Welds made by 0.25%Mo containing wire showed good impact value regardless of both side one run welds and multiple pass welds. 3) Welds made by 0.5%Mo containing wire showed good impact value for both side one run welds, while it was not acceptable value for multiple pass welds.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.5
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• pp.634-644
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• 2001

The test facility of a 1/60-scale model for train-tunnel systems has been recently developed to investigate the effects of tunnel portal shapes, hood shapes and air-shafts for reducing the micro-pressure waves radiating towards the surroundings from the tunnel exit. The present test rig has been advanced from a 1/70-scale facility at NLR in Netherlands. The NLR test rig has the two-wise guidance system that needs two ears attached on the external surface of a model train nose. Therefore, their train models have irregular nose shapes. The main characteristics of the present facility are that the train model is guided by only one wire from the compressed air launcher to the absorber parts of test facility and the wire guidance hole is located at the axial center of a train model. In the present test rig, after a train model is launched, the air jet from the launcher does not enter the tunnel model. Experimental results were compared with numerical predictions to prove the performance of the test facility.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.86-86
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• 2012

The new approaches for silicon solar cell of new concept have been actively conducted. Especially, solar cells with wire array structured radial p-n junctions has attracted considerable attention due to the unique advantages of orthogonalizing the direction of light absorption and charge separation while allowing for improved light scattering and trapping. One-dimenstional semiconductor nano/micro structures should be fabricated for radial p-n junction solar cell. Most of silicon wire and/or pillar arrays have been fabricated by vapour-liquid-solid (VLS) growth because of its simple and cheap process. In the case of the VLS method has some weak points, that is, the incorporation of heavy metal catalysts into the growing silicon wire, the high temperature procedure. We have tried new approaches; one is electrochemical etching, the other is noble metal catalytic etching method to overcome those problems. In this talk, the silicon pillar formation will be characterized by investigating the parameters of the electrochemical etching process such as HF concentration ratio of electrolyte, current density, back contact material, temperature of the solution, and large pre-pattern size and pitch. In the noble metal catalytic etching processes, the effect of solution composition and thickness of metal catalyst on the etching rate and morphologies of silicon was investigated. Finally, radial p-n junction wire arrays were fabricated by spin on doping (phosphor), starting from chemical etched p-Si wire arrays. In/Ga eutectic metal was used for contact metal. The energy conversion efficiency of radial p-n junction solar cell is discussed.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.71-73
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• 2006

AC loss on variation of external magnetic field is a very important factor in development of power applications. In this paper, we measured and compared AC loss of hybrid-multi stacked wire made of the combination of 1G wires and 2G wires and uniform-multi-stacked wire made of one type of wires, 1G wires or 2G wires. Measurement was performed using by the linked-picked coil method. As results, as the number of wires increase, AC loss per unit volume of both stacked wires in low external magnetic field is reduced. Also AC loss of 2G slacked wire is higher than that of 1G wire. AC loss per unit length of 2G stacked wire is less than that of 1G stacked wire. And AC loss of hybrid-multi stacked wire made of the combination of 1G wires and 2G wires was between uniform-multi-stacked wire made of 1G wires and 2G wires.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.7
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• pp.806-813
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• 2016

To alleviate the vibration problem or to satisfy the required criteria for manifesting the guaranteed performance of precise equipment, various vibration isolation materials or apparatus, such as viscoelastic material, air and coil spring, have been developed and applied. Among them, a wire mesh material is regarded as one of the good candidate for reducing the vibration in terms of moderate material price, easy shape machining and long life cycle without the property deterioration induced by the aging or environmental effects. In this paper, prior to wire mesh isolator design, the static and dynamic elastic modulus of wire mesh materials are extracted from the experiment by the simple shaped cylindrical specimens and their characteristics for applying to vibration isolator design are examined. The simple shaped specimens were made as considering the design parameters of a wire mesh mount; i.e. the density, wire diameter and wire mesh slope, and the sensitivity analysis were also performed from a view point of the extracted elastic modulus.