• 한국생산제조학회지
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• 제19권6호
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• pp.859-866
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• 2010

Generally, a fixed type guide-bush system is installed during machining miniature work-pieces with high precision in the multi-task CNC lathe. But a conventional guide-bush system does not provide a constant clamping force under the condition of varying work-piece diameters. It is important to maintain a constant clamping force for guaranteeing machining precision. This paper proposes a new guide-bush system with a pneumatic clamping device for the CNC Swiss-turn lathe to keep constant clamping force with changes in work-piece diameters. Through performance tests, new clamping system developed in the study showed better machining precision at the cost of a small increase in the temperature of the system than conventional systems due to an increase in the frictional heat and a change in the heat transfer route.

• Journal of the Korean Wood Science and Technology
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• 제26권1호
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• pp.51-56
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• 1998

The bast fiber of paper bush misumada have been cultivated in south coast bay of the Korean peninsula were not used to handmade painting paper. Therefore, in using the bast fiber of paper bush misumada manufactured handmade painting paper, tested absorption speed, blot characteristics and organic functions. The results are summarized as follows; The handmade painting paper manufacured only the bast fiber of paper bush misumada proper to the absorption speed of China ink, didn't have difference of the length and width for blot. And it was most fitted to east writing-and-painting using. Also the flexibility excell, and light and shade in overpainting directly appeared, and fitted to black-and-white drawing. And the using increase plan of the paper bush misumada demanded.

• 대한조선학회 특별논문집
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• 대한조선학회 2005년도 특별논문집
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• pp.134-137
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• 2005

Recently, in VLCC, shafting system is stiffer due to large engine power whereas hull structure is more flexible due to scantling optimization, which can be suffered from alignment damage by incompatibility between shafting and hull, In this study, shafting system without stern tube forward bush was adapted for less sensitive system against external factors. Also, shaft alignment analysis was considered with hull deflection at various ship loading conditions and stern tube after bush of long journal bearing was evaluated by static squeezing pressure and dynamic oil film pressure with sloping control. Whirling vibration was also reviewed to avoid resonance with propeller blade order. So, reliable shafting design for VLCC could be achieved through optimized alignment analysis for the system without stern tube forward bush.

• International Journal of Contents
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• 제5권3호
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• pp.33-39
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• 2009

This study tested a path model of agenda building examining the relationship among the media, the public and the presidential statements on the issue of drug abuse during the Bush administration's War on Drugs. The results showed that a dynamic and interactive relationship among aforementioned actors. First, the real-world conditions strongly increased both media coverage and presidential statements. Second, the news media and president influenced each other. Third, public concern, however, did not function as a significant factor in agenda-building process in this study. The result of this study indicates that Bush was not utterly a reactive or proactive president in terms of his relationship with the media. That is, news media and the president interacted regarding the drug issues; the relationship between President Bush and the media for drug issues was reciprocal.

• Tribology and Lubricants
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• 제24권1호
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• pp.21-26
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• 2008

A pin bush bearing is one of the most important element in the piston engine which is joined a piston to a connecting rod. A pin bush is suffered by heat and changeable repeat loads, which are come from the explosive gas heat and pressures during a reciprocating stroke. Therefore, a tribological behavior of pin bush bearings is very severe compared to other parts of a piston assembly. To keep a stable operation of pin bush bearings effectively, it would be satisfied with proper oil film strength for severe operating conditions and durability, which are strongly related to the oil film thickness, oil film pressure, and a friction loss power. The computed results show that the viscosity of engine oils slightly affects to the minimum oil film thickness and oil film pressure distribution, but is an influential parameter on a total friction loss power. Thus the low viscosity engine oils for an increased operation condition should select a high level of base oil and add a viscosity index improver as an oil film additive.

• 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.

• The Korean Journal of Ecology
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• 제18권3호
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• pp.397-408
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• 1995

This study was conducted to analyze the breeding bird community by using guild concept in Mt. Baekwoon Research Forest of Seoul National University. Bird Community was studied by line transect method during the breeding seasons of birds in 1982 and its results were compared and analyzed with the Park et al. Work in 1993. Guilds were characterized by nesting and foraging sites as follows: nesting guild - (H) hole, (C) canopy, (B) bush, (E) edge; and foraging guild - (o) outside, (c) canopy, (b) bush. Bush-nesting guilds such as Tricolor Flycatcher (Ficedula zanthopygia), Blue-and-White Flycatcher (Cyanoptila cyanomelana), Stonechat (Saxicola torquata), Bush Warbler (cettia diphone) and Skylark (Alauda arvensis) had disappeared after ten years. Outside-foraging guilds such as Common Buzzard (Buteo buteo), sparrow Hawk (Accipiter nisus) and Carrion Crow (Corvus corone) also were not observed. There was a sharp decrease of species richness of bush-nesting guild, canopy-foraging guild and bush-foraging guild compared to ten years ago. These decreases indicate that forest environment of this area has been changed for the ten years, and guild concept in this study can be used usefully to elucidate the change of bird community according to the change in forest environment.

• Tribology and Lubricants
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• 제24권6호
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• pp.315-319
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• 2008

This paper presents the interface bonding characteristics between a phosphor bronze and a steel plate for pin-bush bearings. The pin-bush bearing is an important component in which is used to reduce a friction loss and a wear against the piston pin. The pin-bush bearing is manufactured by hot-pressing a phosphor bronze and a back metal of a steel plate. This paper investigated the bonding interface characteristics in which is manufactured by melting a copper based bronze and a steel plate. The hardness from the inner surface of a bronze to the outer one of steel has been measured using a Vickers hardness tester. The experimental results show that the hardness of a bronze is superior to that of the conventional bronze and the transient hardness of pin-bush bearings is gradually increasing to the hardness of the steel back metal. This means that the bonding interface zone of pin-bush bearings may be fabricated by defusing a bronze to the steel plate due to a density difference between two materials.

• 안보군사학연구
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• 통권3호
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• pp.169-196
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• 2005

The point of Bush administraion’s foreign policy is to support the promotion and stability of Democracy in Iraq and counter terrorism and spread of WMD with his strong propulsive force caused by his reelection. In such an environment, there are his leadership, his team, himself, Kim Jung Il, and a new understanding of North Korea after September 11 as the effective factors of Bush administration’s policy toward Pyongyang. Bush administration’s foreign policy of North Korea also shows the process of North Korea’s nuclear weapon program and the future scenario of the Korean Peninsula with "the persistence of solving North Korea’s nuclear weapon program such as the method having done in Lybia", "the holding unconditional talks with Pyongyang, and "the continual concerns with human rights in North Korea." The purpose of Bush administration’s foreign policy of North Korea is to make North Korea do not support terrorism rather than remove the nuclear weapon in North Korea. The process of outlining South Korea’s policy toward North Korea must be considered for "national interest" with reasonable analyses not just hopes For this, South Korea must access systematically human rights of North Korea, prepare projects for a daring approach on North Korea, and strengthen South Korea’s defense ability toward North Korea with deep alliance with U.S and systematize the mutual understanding channel between U.S and South Korea. In conclusion, South Korea must try to get specific methods and practices about Bush administration’s foreign policy of North Korea with national wisdom

• Tribology and Lubricants
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• 제35권2호
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• pp.87-93
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• 2019

This work aims to develop a dry lubricant for oilless bush, especially a solid lubricant, thereby creating a coating method with improved properties of anti-friction and load-carrying capacity without oil lubrication. In this work, spherical-shaped powders of thermosetting resin such as polyimide (PI) are mixed with a binder matrix obtained by mixing a fluorocarbon compound resin such as Polytetrafluoroethylene (PTFE) or Ethylene tetra fluoro ethylene (ETFE) with itself or with a non-fluorocarbon thermoplastic resin such as Polyether ether ketone (PEEK). And these dry lubricant mixtures are thickly coated (200-300 mm in the thickness) on the inner surface of the bush by using a wet-typed air-spray deposition method. It was found that the load-carrying capacity of the solid lubricant for excavator bush (60 mm in diameter) that operates under a high load condition (at 40 MPa) is greatly improved owing to the spherical-shaped powders of thermosetting resin. In addition, the coefficient of friction at the sliding surface is also reduced less than 0.1. Thick coating also lowers the contact stress at the edge of a bush that results in better tribological performances. The result suggests that the lubrication performance and durability life of the bush can be remarkably improved even without lubrication (oil or grease).