• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.9
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• pp.593-598
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• 2015

In this paper, the silencer for large caliber gun to reduce the propagation of gun-generated noise was studied. The results of structural analysis and firing test were described. Structural analysis was conducted by using a commercial program, ANSYS, and showed that there was not any structural problem. The sound pressure level was diminished about 10 dB by the silencer adapted in front of the gun and the soundness of the material was verified from the internal pressure measurement. The reduction of weight, improvement of durability and speed-up of actuating device have to be studied later to improve the usability of silencer for large caliber gun.

• Journal of Welding and Joining
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• v.20 no.4
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• pp.538-543
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• 2002

M/S TB(Mash Seam Tailored Blank) is a production method for blanks by welding together blanks of different material, thickness and coating, and is an attractive method for manufacturing car body because it makes parts lighter and can save the cost and time to manufacture. However, there have not been quantified criteria to evaluate the quality of TB weld. This study introduced FHR (failure height ratio) in order to assess formability or/and weldability of the M/S welds and the applicability of FHR was confirmed by actual auto body forming and FLD tests. Furthermore, a new parameter, HN(heat number) based on the heat input of "$Q=I^2Rt$" was proposed and assessed. It was found that the concept of HN could be utilized to evaluate the soundness of M/S welds without any destructive tests.ive tests.

• Proceedings of the KWS Conference
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• 2004.05a
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• pp.305-307
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• 2004

One set of rotor coils is required per each large generator rotor assembly, Rotors consist of two directly opposing poles. Each pole requires from 5 to 9 coils. Each coil is made up of two halves identified on the connection end. These coil halves will be joined together by butt brazing process during subsequent rotor assembly. Each half coil is made up of typically 4 to 9 layers of copper conductors. Because of Generator rotor is rotated very high speed with 3,600RPM, the quality soundness of brazed joints is very important at each coil. But, it is very difficult to be optimized non-destructive evaluation, because c-coil has the long shape and evaluation is to be done assembled condition. In this paper introduce newly developed inspection process and acceptance standards for the ultrasonic inspection of " C" coil butt braze. This inspection system is a semi-automatic ultrasonic flaw detector with data acquisition and retention capable of assessing the relative lack of bond of brazed butt joints

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1794-1796
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• 1996

In order to evaluate the soundness of 10 year service-aged XLPE-insulated 22.9 kV underground distribution cables, semiconductive shields have been characterized. The edge of insulation near the insulation shield shows a drastic decrease of OIT. Impurities such as Ca, Mg, Fe, Cu were detected in both conductor and insulation shields. Their concentrations at the insulation shield are much higher than those at the strand shield. All these facts suggest that the edge of insulation near the insulation shield is degraded considerably, which might be attributed to the oxidation reaction of insulation by a large amount of impurities in the insulation shield.

• Review of KIISC
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• v.5 no.1
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• pp.25-46
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• 1995

소프트웨어 개발에서, 사용자 요구 사항을 잘 표현하면 할수록 시스템은 오류가 적고, 사용자가 요구하는 시스템으로 만들어지며, 시스템 검증이 쉬워지는 것 같이, 정형적 사양(formal specification)은 시스템 개발 전반에 영향을 준다. 이 정형적 사양은 암호 프로토콜이 완전(completeness)하고 안전(soundness)한가를 검증하는 데에도 유용하게 사용될 수 있다. 암호 프로토콜을 사양하고 분석하는 방법은 크게 대수적, 논리적, 상태 변환적 접근 방법등과 통신 프로토콜의 검증에 쓰는 패트리넷을 이용한 방법등이 있다. 이들 방법중에는 프로그램으로 구현되어 자동 검증 tool로 개발된 사례도 있다. 본 고에서는 암호 프로토콜을 위한 사양 기법과 그에 따른 분석 기법을 알아보고 그것들을 비교, 분석하였다.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1377-1380
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• 2008

An irradiation test of a nuclear fuel rod having external and internal tube structure was planned for a performance. To establish fabrication process satisfying the requirements of irradiation test, micro-TIG welding system for fuel rods was developed, and preliminary welding experiments for optimizing process conditions of fuel rod was performed. Fuel rods with 15.9mm diameter and 0.57mm wall thickness of cladding tubes and end caps have been used and optimum conditions of endcap welding have been selected. In this experiment, the qualification test was performed by tensile tests, helium leak inspections, and metallography examinations to qualify the endcap welding procedure. The soundness of the welds quality of a dual cooled fuel rods has been confirmed by mechanical tests and microstructural examinations.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.871-876
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• 2001

One-touch fittings are important components that can make a quick and tight connection between pneumatic pipe systems. In this study, the stress analyses with various working pressures on these one-touch fittings are carried out using finite element method. Material properties, to use the stress analyses, are measured by the universal tester and digital Vickers hardness tester. The stress analyses on the circular shell spring forced by various pressures(100, 150, 200, 250kpa) and on the main body due to the fluid-structural interaction are investigated. Results show that the stresses of one-touch fitting are concentrated to supported part of main body and the soundness of a circular shell spring with maximum pressure 250kpa was confirmed.

• Korean Journal of Materials Research
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• v.11 no.10
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• pp.813-819
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• 2001

The microstructure and the distribution of hardness of Co and A1 alloy powder cladding layer in high carbon 9CrSi alloy steel for roll materials cladded by laser surface cladding were investigated. And, for the evaluation of soundness as the roll materials, we examined the wear resistance of the cladding materials with the wear appratus of pin on disc type. The experimental results showed that the microstructure of laser cladding layer was constituted with the clad surface layer, the alloy layer, the heat treatment layer with base metal. The wear resistance of Ni alloy Powder cladding material was superior to that of Co alloy powder cladding material both at the low speed (0.46m/s) and the high speed(0.92m/s). It seemed that the behavior of wear showed the abrasive wear at the early stage and the adhesive wear at the late stage.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.265-267
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• 2002

In this paper, the communication between Over-Current Relay agents is realized using DNP(Distributed Network Protocol), which is the standard communication protocol of distribution automation system in KEPKO. The key words in OCR agent communication are defined and represented by use of DNP application function code. And the DNP index for OCR agent is defined. The proposed communication scheme is tested by use of Communication Test Harness, a test tool for DNP protocol to show its soundness.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1108-1110
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• 1999

This paper describes the comparison results on electrical characteristic changes of ZnO blocks by lightning impulse current. The five types of ZnO blocks used in lightning arrester for distribution lines have been estimated repeatedly till about 400 times by a standard lightning impulse current of 3kA, $8/20{\mu}s$, and changes of the performance characteristics of them to operation times were examined and compared quantitatively every fifty times discharge. It is expected that the result will be useful to diagnose the soundness of ZnO blocks or lightning arresters, and to develope deterioration diagnosis device for them.