• The Journal of the Acoustical Society of Korea
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• v.9 no.3
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• pp.24-30
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• 1990

In this paper, meander line type EMAT(Electro-Magnetic Acoustic Transducer) has been designed and fabricated with effective properties for detecting flaw existing within one wavelength in depth, and its characteristics have been analyzed. For the purpose of getting effective dynamic and static magnetic intensity, the coil has been arrayed using wire with interval of 0.75 mm and width of 0.65 mm and permanent magnets with 1500 Gauss have been constructed respectively. The center frequency and fractional bandwidth of the fabricated EMAT was 2 MHz and 36% respectively and its impulse response has been measured by non-contacting technique(the distance between the conducting media and the coil was 0.15mm). In the measuring results, it has been shown that Insertion Loss(IL) was 45.46dB and it was good agreement with theoretical result.

• Journal of Welding and Joining
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• v.23 no.2
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• pp.66-74
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• 2005

API(American Petroleum Institute) steel, as a line pipe material, requires the enhanced mechanical and chemical properties with the environmental severity. Especially, the weld part(weld metal and heat affected zone) is an important region for the safety. However, the study for the behavior of microstructure and toughness in multi-pass welding is seldom. In this study, the relationship between the microstructure and toughness of welds with several welding, bending and heat-treatment conditions was examined. In particular, HIC property in the weld metal was evaluated. The microstructure and toughness in multi-passed HAZ seemed to be determined by the final welding thermal cycle and the low toughness was attributed to the MA constituents formed in the intercritically reheated region. The weld metal showed very low toughness and it was not improved by the change in bending and heat treatment conditions. Additionally, the cracks are observed in the weld metal. from these results, it was found that the choice of welding wire/flux is very important.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.6
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• pp.225-229
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• 2011

Most of the silicon cutting methods using the multi-wire with the slurry injection have been used for wafers of the crystalline solar cell. But the productivity of slurry injection cutting type falls due to low cutting speeds. Also, the direct contact with the metal wire and silicon block increases the concentration of metallic impurities in the wafer's surface. In addition, the abrasive silicon carbide (SiC) generates pollutants. And production costs are rising because it does not re-use the worn wire. On the other hand, the productivity of the cutting method using the diamond coated wire is about 2 times faster than the slurry injection cutting type. Also, the continuous cutting using the used wire of low wear is possible. And this is a big advantage for reduced production costs. Therefore, the cutting method of the diamond coated wire is more efficient than the slurry injection cutting technique. In this study, each cutting type is analyzed using the surface characteristics of the solar wafer and will describe the effects of the manufacturing process of the solar cell. Finally, we will suggest improvement methods of the solar cell process for using the diamond cutting type wafer.

• Journal of the Korea Computer Industry Society
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• v.5 no.9
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• pp.1095-1100
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• 2004

The computer system is gradually complicated because of explosive growth of computer system and IT technology. For efficient management of complicated system, system load monitoring technology is essential. In this paper, we is implemented the real-time load monitoring system based mobile than the traditional methods that are used load-related commands in system manager or specific load application programs based connected wire. Advantage of implemented load monitoring system in this paper is freely saw load information in time and space though mobile method like as PDA, cellular phone, more than traditional methods intime and space.

• Explosives and Blasting
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• v.18 no.3
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• pp.49-58
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• 2000

본 논문은 양면발파에 의한 채석기술에서 주로 양면발파 장약패턴 및 다이아몬드 와이어쏘절삭기술에 관한 내용을 중심으로, 현재 각 석재광산에서 시행하고 있는 채석기술과 연구소 에서 시행한 현장 시험발파 결과를 기술한 것이다. 첫째, DA석재광산에서는 제트버너를 이용하여 자유면을 형성하고, 일면발파법과 양면발파법의 작업시간을 비교한 결과 양면 발파할 때에 37%이상의 작업시간 절약효과가 있었으며, 인원은 36%이상의 감소효과가 있었다.둘째, DH석재광산에서는 다이아몬드 와이어쏘를 이용하여 자유면을 형성하고 양면발파 작 업시간과 타 광산에서 일반적으로 사용하고 있는 제트버너에 의한 양면발파 작업시간을 비교하였을 때에 21%이상의 절감효과가 있었고, 작업인원도 21%이상의 감소효과가 있었다. 다이아몬드 와이어쏘를 이용하여 양측면에 자유면을 형성하고 양면 발파하는 채석기술은 소음 및 분진에 의한 환경공해를 방지할 수 있었으며, 작업공정 및 경제성 면에서도 매우 유 리하나 실패시 다른 채석기술에 비해 모암의 손상으로 인한 경제적 손실이 커질 수 있다는 단점도 있으므로 정밀한 발파설계 및 기술이 필요하다.

• Journal of Welding and Joining
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• v.12 no.3
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• pp.18-25
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• 1994

최근 건축용 강구조물이 초대형화 및 초고층화됨에 따라 용접물량의 급증하고 있으나 3D 직종에 대한 회피현상으로 용접기능자의 감소 및 인건비의 급증 등으로 인하여 건축용 강 구조물 제작시 경쟁력이 갈수록 저하되고 있다. 이에 대한 자구책으로 강 구조물 제작업체에서는 생산 성을 한층 배가 시킬 수 잇는 용접시공 기술을 자체 개발하거나 외부로부터 도입하고 있다. 본 보에서는 당사를 비롯하여 여러 업체에서 최근 개발된 용접기술 특히 대전류 SAW 기법, SESNET 기법 등의 초대입열 용접기술, Metal cored wire나 TIME 기법에 의한 고능률 GMAW 기법 및 Robot 용접 등에 대하여 간략히 기술하였다. 이 용접기술들의 적용에는 대개 고가의 시설투자가 수반되나, 이는 생산성 증가에 따른 원가절감으로 충분히 상쇄될 수 있다. 그러나 상기된 용접기술들의 적용에 대한 성패는 용접장비의 특성, 용접조건의 확립, 모재의 특성 혹은 주변 자동화 기술 및 상호 종속적인 관계에 크게 의존된다. 따라서 가 강 구조물 제작업체에서는 세심한 주위환경 분석을 토대로 각 업체에 가장 합당한 용접기술을 선정 및 적용하여야 하겠다.

• Proceedings of the KWS Conference
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• 2005.11a
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• pp.29-31
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• 2005

The purpose of this study is to establish the predictive equation of the distortion at the ES and SA weldment of Cr-Mo low alloy steel. In order to do it, the effect of heat input, plate thickness and strip wire width for ESW on the distortion at the ES and SA weldment was evaluated using FEA. Based on the results, the principal factors controlling the distortion of the ES and SA weldment were identified and the predictive equation was established.

• Journal of Chest Surgery
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• v.24 no.7
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• pp.719-724
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• 1991

A case of pulmonary atresia with intact ventricular septum was presented in a 10-month-old cyanotic female patient, which was congenitally rare. Infant with pulmonary atresia and intact ventricular septum usually require urgent surgical intervention. Angiogram showed the pulmonary atresia at the level of the pulmonary valve, the hypoplasia of tricuspid valve and atrial septal defect without patent ductus arteriosus. We performed the pericardial patch graft on the right ventricular outflow tract and pulmonary artery after ventriculotomy using pacemaker wire as electrical saw and main pulmonary arteriotomy and then modified Waterston shunt from the ascending aorta to patch on the right ventricular outflow tract without extracorporeal circulation. Patient was postoperatively good condition.

• Journal of Ocean Engineering and Technology
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• v.18 no.2
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• pp.70-76
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• 2004

In the steel marking industry, most companies have adapted the continuous casting process, due to its economical benefit. Casting rolls are utilized for frictional drive and the transport of solidifying slap. Dimensional tolerances, mechanical stability, and surface condition of the casting rolls can affect both the surface and the internal quality of the product being cast. To overcome these problems, the industry now is focused on accelerating the rate of technological improvements. This study has been undertaken for the development of casting rolls overlaid materials (SAW FCW wire), with the addition of Vanadium and Molybdenum to the martensitic stainless steel, in order to increase tensile strength and hardness at elevated temperatures.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.320-323
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• 2002

This paper presents a new generation of system for pressure vessel and shipbuilding. Typical pressure vessel and ship building weld joint preparations are either traditional V, butt, fillet grooves or have narrow or semi narrow gap profiles. The fillet and U groove are prevalently used in heavy industries and shipbuilding to melt and join the parts. Since the wall thickness can be up to 6" or greater, welds must be made in many layers, each layer containing several passes. However, the welding time for the conventional processes such as SAW(Submerged Arc Welding) and FCAW(Flux Cored Arc Welding) can be many hours. Although SAW and FCAW are normally a mechanized process, pressure vessel and ship structures welding up to now have usually been controlled by a full time operator. The operator has typically been responsible for positioning each individual weld run, for setting weld process parameters, for maintaining flux and wire levels, for removing slag and so on. The aim of the system is to develop a high speed welding system with multitorch for increasing the production speed on the line and to remove the need for the operator so that the system can run automatically for the complete multi-torch multi-layer weld. To achieve this, a laser vision sensor, a rotating torch and an image processing algorithm have been made. Also, the multitorch welding system can be applicable for the fine grained steel because of the high welding speed and lower heat input compare to a conventional welding process.