• Corrosion Science and Technology
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• v.12 no.3
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• pp.142-148
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• 2013

Safety is a major concern in Nuclear Power Plants (NPPs). Piping systems in NPPs are very complex and composed of many components such as tees, elbows, expanders and straight pipes. The high pressure and high temperature water flows inside piping components. As high speed water flows inside piping, the pipe wall thinning occurs in various reasons such as FAC (Flow Accelerated Corrosion), LDIE (Liquid Droplet Impingement Erosion) and Flashing. To inspect the wall thinning phenomenon and protect the piping from damages, piping components are checked by UT measurement in every overhaul. During every overhaul, approximately 200~300 components (40,000~60,000 UT data) are examined in NPPs. There are some methods from EPRI for evaluating wear rate of components. However, only few studies have been conducted to find out the raw data reliability for the wear rate evaluation. Securing the reliable raw data is the key factor for a reasonable evaluation. This paper suggests the reliability analysis method for the repeatedly measured data for wear rate evaluation.

• Convergence Security Journal
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• v.3 no.3
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• pp.51-57
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• 2003

The Real-time DBMS must provide the keeping, fabrication and control function which the data where the user requsets for processing inside the hour when it is restricted, it is quick most and safely[3]. In order lide this to take chare of the real-time control and fabrication function, details recording (log) of the control processing is very important in accomplished transactions from inside the Real-time DBMS. In this proposal, it sees recording which is like this in base and it proposes the new recovery function for transactions log. This recovery technique which it sees used the concept of the LIFO (Last-In-First-Out) method with basic. The proposed technique will becomes the technique which it will be able and to record to process efficiently with a same attribute and the continuous transactions log.

• Proceedings of the KSMRM Conference
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• 2001.11a
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• pp.176-176
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• 2001

목적： 기존의 역수신코일(inside-out receiver coil)로 관벽의 MR 영상을 얻을 때 영상영역이 좁고 수신감도가 불균일한 단점을 보완하면서 신호대 잡음비(S/N ratio)도 높일 수 있는 회전자계역수 신코일(quadratic inside-out receiver coil)의 개발을 목적으로 한다. 대상 및 방법： 8극형코일, 선형자계수신코일, 회전자계수신코일에 대하여 컴퓨터 모의실험으로 영상영역 및 감도의 균일성을 비교하였다. 회전자계수신코일은 안장 모양을 한 두 개의 선형자계코일이 서로 간섭이 일어나지 않도록 수직 방향으로 배열된 구조를 갖도록 하였다. 지름 3 cm 크기로 각 코일을 제작하였으며 지름 20 cm의 원통 중앙에 내경 4 cm의 관이 있는 팬텀을 만들어 MnC1$_2$를 섞은 물을 채운 다음 1.5T 초전도 MRI 장치와 0.3T 영구자석 MRI 장치에서 팬텀의 관벽 영상을 얻었다. 본 실험을 시행한 1.5T 장치의 구조 때문에 회전자계코일의 두 안장코일을 결합하는 회로를 제작하여 사용하였고 0.3T에서는 장치에 내장된 결합회로를 사용하였다. 또한 포르말린 용액에 보관된 소의 대장 조직 단면 영상을 FOV 10-12 cm로 얻어 회전자 계안장코일의 성능을 평가하였다.

• Journal of Environmental Impact Assessment
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• v.4 no.2
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• pp.123-130
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• 1995

The equipment composed of many complicated electronic stuffs undergoes diverse stresses caused by mechanical vibrations during its service. Thus, to ensure its proper operation in the field a simulated vibration test has to be carried out in the laboratory with the Vibration Qualification Level, the test specification, which can include the real environment. In this paper we intent to deal with method and procedure for determining the Vibration Qualification Level so as to estimate the vibration-endurance for the equipment precisely.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.2
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• pp.66-73
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• 2018

A computational fluid dynamics simulation of pyrotechnic material combustion inside a cylindrical closed vessel was carried out using the Eulerian-Lagrangian method. The 5th order upwind WENO scheme and the improved delayed detached eddy turbulence model were implemented to capture shock waves. The flow structure was analyzed inside the cylindrical vessel with a pressure sensor installed at the side wall center. The analysis revealed that the pressure oscillated because of the shock wave vibration. Additionally, the simulation results with four different sensor tab depths implied that, inside the sensor tab, eddies were generated by the excessively large gap between the sensor diaphragm and the side wall. These eddies caused irregularity to the measured time-pressure curve, which is an undesirable characteristic.

• Journal of Radiation Protection and Research
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• v.12 no.1
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• pp.34-39
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• 1987

Radiation shielding analysis for a 6MeV X-ray facility was carried out. The primary and leakage radiation for the facility can be evaluated based on the methodology in NCRP No. 49 and 51. The present study deals with radiation scattering analysis for the outside and inside door of the facility based on the albedo concept. The calculated dose rates were compared with the results of MORSE-CG code calculation and the measured data, resulting in a good agreement, even though there existed some deviation for the inside door. These results can be utilized to the radiation shielding design of the medical and industrial X and gamma ray facilities, and to the safety evaluation of these facilities.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.5
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• pp.556-560
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• 2001

Remote field eddy current testing (RFECT) with through-wall transmission characteristic is being applied to pipes ranging from small tubes of heat exchanger to natural gas supply pipelines. Cast iron pipes with nominal diameter of 100mm are used primarily as the waterline pipes. The leakage of water occurs due to defects in the pipes caused by vibration of automobiles and corrosion. But, the use of direct inspection methods such as insertion of inspection equipment inside the pipelines has been limited due to its lack of economical efficiency. Economical development of inspection equipments is possible since RFECT method can be easily employed for system integration and quantitative evaluation of both inside and outside defects. In this study, the development of underground pipeline inspection system was tarried out by using RFECT method in consideration of the characteristics of waterline network. This paper specifically describes the design and production of RFECT pipeline inspection pig using centralizer mechanism, development of remote field eddy current signal acquisition and processing software, and review of RFECT system operation procedures.

• Journal of Mushroom
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• v.9 no.2
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• pp.74-79
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• 2011

This study was carried out to develop a method related to measuring the temperature of sterile medium in bottle cultivation. When the medium is sterilized, the device is able to be inserted inside of the medium and the temperature can be directly measured in real time although high temperature and pressure are detected in the sterilization. This device can be able to measure the sterilization temperature in short intervals inside of autoclave and medium used in bottle cultivation. As the method were applied to the field cultivation of mushroom, we could produce mushroom in consistent manner through the optimum sterilization of the medium.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.12
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• pp.1144-1149
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• 2007

Experimental studies on the fabrication of sub-30 nm nanofibers using weakly two-photon induced photopolymerized region have been carried out. For the generation of nanofibers inside or outside microstructures, an over-polymerizing method involving a long exposure technique (LET) was proposed. Such nanofibers can find meaningful applications as bio-filters, mixers, and many other uses in diverse research field. A multitude of nanofibers with a notably high resolution (about 22 nm) in two-photon polymerization was achieved using the LET. Furthermore, it was demonstrated that the LET can be employed for the direct fabrication of various embossing patterns by controlling the exposure duration and the interval between yokels. Thin interconnecting networks are formed regularly in the boundary of the over-polymerized region, which allows for the creation of various pattern shapes. Overall of this work, some patterns including nanofibers are fabricated by the LET.

• Archives of Plastic Surgery
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• v.37 no.2
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• pp.199-201
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• 2010

Purpose: Except for continuous suture in skin layer, stitching out in facial laceration, we have to hold each knots up and cut the knots by No. 11 blade or small scissors. However, we often have difficulty in stitching out the knots on children who do not cooperate well. Therefore we introduce an easy and fast stitch out method of pediatric lacerations. Methods: From January to May 2009, we studied 15 pediatric patients (mean age 5.6 years old) who had facial laceration on face or underwent any surgery on operation room. For easy stitch out, we left the one string of the first knot long enough to extend at the opposite end of laceration site. And then the extended string was fixed to skin using Steri-strip. Next we do simple interrupted suture including the extended traction nylon string inside the knot. Through this method, we can stitch out all knots simply by lifting up the traction nylon needless to hold the each knot one by one. Results: Until stitching out, the traction nylon was just right position and there was no normal tissue injury during stitch out all knots. Patients were satisfied with the short stitch out time. Conclusion: By using the traction nylon on pediatric laceration suture, we can stitch out all the knots with no normal tissue injury in less time.