• 한국광물학회:학술대회논문집
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• 한국광물학회.대한자원환경지질학회.대한광업진흥공사 2002년도 추계 공동 심포지엄 논문집: 국내 자원의 현황과 전망
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• pp.137-151
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• 2002

최근 급속한 첨단산업의 발전과 더불어 각 분야에서 신소재 개발 등의 연구가 활발히 진행되고 있어 비금속 자원은 그 수요가 점차 증가하는 추세에 있다. 여러 비금속 자원 중 장석은 세라믹, 법랑, 타일, 유약용 등의 요업원료와 유리, 용접봉, 플라스틱, 페인트, 카리비료등 무기 재료 공업원료로 다양하게 사용되고 있는 비금속자원 이다. 2001년도 우리나라 장석 생산량은 389,361톤 (2001년도 광산물 수급현황, 2002, 5, 산업자원부)이며 매장량은 41,470,000톤 (2001년도 광산물 수급현황, 2002, 5, 산업자원부)이며 전국적으로 등록된 장석 광구수는 811개에 개발광산은 69개 이른다. 이상의 예를 보면 막대한 양의 매장량과 장석 광산이 알려져 있지만 실제 연중 가행 광산은 10개 광산 미만이며 영세한 상태로 체계적인 개발이 이루어지지 못하고 있다. 이런 문제점을 해소하고 장석 자원의 확보 및 안정적 공급을 위하여 장석의 정의, 용도, 품질요건, 부존, 산출상태, 가행광산현황 및 장석자원현황등을 규명하여 장석광산의 향후. 개발대책 및 고부가가치화에 필요한 자료를 제공하고자 한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.322-325
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• 2000

In the previous report1), the grinding characteristics of quartz were investigated. In this paper, the grinding mechanisms of brittle materials including ceramics and quartz are modeled and a new parameter SDR(Surface roughness Direction Ratio) is proposed to characterize the grinding mechanisms of such materials. A set of experiments were performed to verify the effectiveness of the suggested parameter. The experimental results indicate that the plastic deformation is the dominant material removal mode at the grinding conditions which show the higher value of SDR. In the case of quartz, the material was removed by brittle fracture in a lower value of SDR and by plastic deformation in a higher value of it. SDR is not affected by wheel mesh size when brittle fracture occured. But in the plastic deformation case, SDR value increases with wheel mesh size.

• Journal of Welding and Joining
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• 제19권6호
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• pp.630-635
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• 2001

The characteristics of spatter generation in the short circuit transfer region of $CO_2$ welding was investigated. Spatteriing phenomena could be classified into three types : Type I generated due to the abrupt increase of arc voltage in arcing duration. Type II by the gas ejection from molten metal and Type III generated by the arc instability at the moment of arc re-ignition just after short circuiting. Main observed types were dependent on the chemical composition of welding wires. The case of YCW12 wires was mainly composed of spatters generated by Type l and Type II, while most, spatters in YCW11 wires were generated by Type II and Type III.

• Journal of Welding and Joining
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• 제12권4호
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• pp.35-40
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• 1994

비파괴검사(NDT)란 시험품에 손상을 주지 않고 내.외부에 존재하는 불연속부(결함)을 찾아내는 방법으로 다음과 같이 그 종류를 분류할 수 있다. (1) 표면결함 검출을 위한 비파괴검사 - 육안검사(VT) : 확대경 등에 의한 치수, 형상확인 - 자분탐상검사(MT) : 강자성체에 적용, 표면(하) 결함검출 - 침투탐상검사(PT) : 금속, 비철금속에 적용, 표면개구 결함검출 - 와류탐상검사(ET) : 도체 표층부(봉, 관 등) (2) 내부결함 검출을 위한 비파괴검사 - 방사선 투과검사(RT) : 결함의 종류, 형상의 판별 우수 - 초음파 탐상검사(UT) : 균열 등 면상 결함검출 등 우수 (3) 기타 비파괴검사 - Strain 측정 : 안전성 평가 - 음향방출시험(AET) - 누설시험(LT) - 중성자 방사선시험(NRT) 이상에서 보는 바와 같이 여러 종류의 비파괴검사가 있으나, 그 중에서 용접부에 적용되는 가장 일반적인 검사방법인 방사선 투과검사에 대해 기술하고자 한다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2004년도 춘계 학술발표대회 개요집
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• pp.152-153
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• 2004

A pressure reversal is where ERW pipes fail at an applied pressure lower than one experienced previously. The susceptibility to pressure reversals of ERW joints has been investigated by varying heat input in the range of 230-268㎾ power and seam annealing temperature of 850-970$^{\circ}C$. The application of repeated loading to notched three point bend specimens was used in this study. There was no occurrence of reversals in all the condition investigated. Furthermore, the bond line ductility is found to be satisfactory. These results can be explained by the fact that a bond line free from defects is successfully obtained from a wide range of ERW conditions.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.293-298
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• 2008

This paper attempts to quantify the effect of mismatch in creep properties on steady-state stress distributions for a welded branch vessel. A particular geometry for the branch vessel is chosen. The vessel is modeled by only two materials, the base and weld metal. Idealized power law creep laws with the same creep exponents are assumed for base and weld metals. A mismatch factor is introduced, as a function of the creep constant and exponent. Steady-state stress distributions within the weld metal, resulting from threedimensional, elastic-creep finite element (FE) analyses, are then characterized by the mismatch factor. We can find that average stresses in the weld can be characterized by the mis-match factor. And there is an analogy between elastic-creep and elastic-perfectly plastic.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.256-261
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• 2001

Corrosion and tensile properties of zircaloy-4 cladding tube having a laser welding part in elevated temperature are studied to present the criterion of quality evaluation in nuclear reactor and to found the scientific basis of SCC, with laser welding method using by coupling up cladding tube to end cap. In the result of tensile test($400^{\circ}C$), the fracture is not happened in the welding part but base metal and the result of corrosion test($400^{\circ}C$ 1500psi steam), corrosion rate of the molten zone and PMZ is a little higher than the other zone.

• Journal of Welding and Joining
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• 제17권1호
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• pp.55-61
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• 1999

The effect of S content in welding wires on the arc stability was investigated, in the region of short circuit transfer and spray transfer. In the region of short circuit transfer, with increasing S content, average arcing time and average short circuit time were decreased. Therefore, droplet transfer frequency was increased, due to the reduction of arcing time and peak current at the moment of arc-reiginition was decreased, due to the decrease of short circuit time. In the region of spray transfer, the fluctuation degree of arc current and arc voltage became more stable, with increasing S content.

• Journal of Welding and Joining
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• 제19권1호
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• pp.88-94
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• 2001

DUPIC (Direct use of spent PWR fuel in CANDU reactors) nuclear fuel is a CANDU fuel fabricated remotely from spent PWR fuel materials in a hot cell. The soundness of the end closure welds of nuclear fuel elements is an important factor for the safety and performance of nuclear fuel. To evaluate the soundness of the end closure welds of DUPIC fuel element, a precise X-ray inspection system is developed using a micro-focus X-ray generator with an image intensifier and a real time camera system. The fuel elements made of Zircaloy-4 and stainless steel by an Nd:YAG laser welding and a TIG welding aye inspected by the developed inspection system. The soundness of the welds of the fuel elements was confirmed by the X-ray inspection process, and the irradiation test of DUPIC fuel elements has been successfully completed at the HANARO research reactor.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2007년 추계학술발표대회 개요집
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• pp.3-5
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• 2007

In recent time there are vigorous requirement for the use of thick steel plate in various industrial fields including shipbuilding industry. Especially, with the continual increases in marine transportation volumes on a global scale, the steel of container ships have become thicker and thicker with the increased size of ships. In addition to, the brittle crack arrestability of heavy thick plates were big issue, in recently. In this study, crack arrest test were conducted in order to investigate the crack arrestability of thick plates for shipbuilding steels, where test plate thickness were 50mm and 80mm. This paper introduce the brittle crack arrestability of heavy thick plates for shipbuilding.