• 한국산학기술학회논문지
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• 제12권1호
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• pp.7-14
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• 2011

연질 동관은 조선, 자동차, 플랜드, 냉동공조 기기 등에 많이 사용되는 대표적인 파이프 재료 중의 하나이다. 그러나 이러한 재료들은 벤딩가공시 외부의 주름, 스프링백, 관이 얇아지는 현상들이 자주 발생하여 문제가 된다. 본 논문에서는 연성재질을 벤딩시 맨드럴이 슬라이딩 가이드 레일을 따라서 파이프를 누르는 벤딩방식을 선택한 연성재질 전용 벤딩머시인을 제작하여 이와 같은 현상을 줄였다. 이의 성능을 확인하는 과정에서 재료로 사용한 동관의 직경이 작을수록 스프링백 현상은 증가하였고 또한 굽힘각도가 클수록 컸다. 또한 동관의 벤딩시 주름이 거의 발생하지 않는 성형품을 제작할 수 있었다.

• Nuclear Engineering and Technology
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• 제54권1호
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• pp.152-161
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• 2022

We analyzed mitigation strategies for steam generator tube rupture (SGTR) accidents using MARS code under both full-power and low-power and shutdown (LPSD) conditions. In general, there are two approaches to mitigating SGTR accidents: supplementing the reactor coolant inventory using safety injection systems and depressurizing the reactor coolant system (RCS) by cooling it down using the intact steam generator. These mitigation strategies were compared from the viewpoint of break flow from the ruptured steam generator tube, the core integrity, and the possibility of the main steam safety valves opening, which is associated with the potential release of radiation. The "cooldown strategy" is recommended for break flow control, whereas the "RCS make-up strategy" is better for RCS inventory control. Under full power, neither mitigation strategy made a significant difference except for on the break flow while, in LPSD modes, the RCS cooldown strategy resulted in lower break and discharge flows, and thus less radiation release. As a result, using the cooldown strategy for an SGTR under LPSD conditions is recommended. These results can be used as a fundamental guide for mitigation strategies for SGTR accidents according to the operational mode.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권4호
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• pp.317-323
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• 2005

To increase the operating speed of the solenoid actuator, this paper proposed a modified model using a non-magnetic ring, which is welded on the magnetic guide tube, and also presents the characteristic equations, results of Finite Element Method (FEM) analysis for magnetic flux distribution and density in magnetic flux paths, and computer simulation results for the dynamic characteristics of plunger motion according to the stroke and time variation. As well, we proved the non-magnetic ring effect by experiments using prototypes.

• 대한기계학회논문집A
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• 제34권2호
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• pp.227-235
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• 2010

본 논문은 방사성시설에서 원격취급 작업을 위해 사용되는 서보조작기와 같은 장비의 이송을 위해 개발된 텔레스코픽 튜브를 갖는 천정이동장치의 설계에 관해 소개한다. 천정이동장치는 z-방향으로 신장, 수축이 가능한 텔레스코픽 튜브, 전력 및 신호 케이블의 관리를 위한 케이블 시스템, 횡행 움직임과 서보구동부 모듈수납을 위한 트롤리 시스템으로 이루어져 있다. 천정이동장치의 작업환경은 설계에 기하학적인 제약을 주게 되는데, 시설의 높이가 낮고 텔레스코픽 튜브의 수축시 길이가 짧아야하며 스트로크는 커야한다는 요구사항을 갖는다. 텔레스코픽 튜브 어셈블리는 위 제약조건을 만족하도록 비선형계획법을 풀어 최적의 치수를 선정하였다. 텔레스코픽 모션으로 발생하는 케이블 길이의 변화를 수용할 수 있는 케이블 시스템을 소개하였고, 또한 천정이동장치 시스템의 충분한 구동을 위한 서보구동부의 선택지침을 소개하였다.

• 디지털융복합연구
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• 제14권8호
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• pp.423-429
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• 2016

본 연구는 대표적인 영상 공유 사이트인 유튜브와 비메오를 사용자 관점에서 비교 분석하고 이를 통해 인터페이스 디자인에 따른 사용자 경험의 개선 방향을 제안하는 데 목적이 있다. 1차로 문헌연구를 통하여 현재 제공되고 있는 서비스 현황과 이론적 배경을 고찰하고, 앞으로의 서비스 전망에 대하여 비교 분석하였다. 2차로 스티븐 앤더슨(Stephen Anderson)의 Creating Pleasurable Interfaces 6가지 원칙을 바탕으로 심층인터뷰를 진행하였다. 그 결과, 유튜브의 경우 기능에 대한 접근성 저하와 광고량 과다로 편의성 개선이 필요하였다. 비메오의 경우 대중적 콘텐츠 부족으로 인한 대중성 향상과 개인 방송 시스템, 커뮤니티 등과 같은 관계성 서비스가 필요한 것으로 나타났다. 본 연구를 바탕으로 앞으로 영상 공유 사이트의 사용자 경험 개선 방안을 위한 참고 자료로 사용될 수 있을 것을 기대하며, 이후 진행될 다른 분야의 사용자 경험 연구에도 도움이 되길 바란다.

• 대한인간공학회지
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• 제29권4호
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• pp.569-574
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• 2010

After the beginning of Web2.0 era, newly developed interaction design patterns based on Ajax(Asynchronous JavaScript and XML) have been tried in various Web2.0 services. These new interaction design patterns enable web service to provide rich experience for users. However, it is very hard to find organized task based guideline about Web2.0 interaction design even though there are a lot of complicated interaction design techniques and patterns. It is essential to have Web2.0 interaction guide based on Ajax because it can guide designers to use appropriate interaction design patterns and to keep usability for ordinary users. Therefore, this research aims to establish task based interaction design guideline for Web2.0 service based on Ajax. The reason why this research focused on Ajax is that Ajax is most widely used language for Web2.0 service. First, primary five interaction design patterns were defined through analysis of various interaction design patterns from Web2.0 services. Second, detail interaction design tasks from five major patterns were analyzed based on the study of major Web2.0 services such as Gmail, Twitter, YouTube and Google maps. Third, general design guidelines such as heuristic guidelines for web service are studied through literature review. After all, this study proposed task based interaction design guide for Web2.0 service with Ajax. With this guide, designers and developers can choose appropriate Web2.0 interaction patterns and apply to their service and provide service to users with enhanced usability and satisfaction.

• 한국초등과학교육학회지:초등과학교육
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• 제23권4호
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• pp.318-325
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• 2004

The purpose of this study is to improve the experiment of dihydrogen production which was newly added to the 7th curriculum of the elementary science education. For this study, the teachers who had taught 6th grade students were asked about the difficulties they ever had in the dihydrogen production experiment by questionnaire. And the contents of the science textbook and teachers' guide book were analyzed. According to this investigation, the following controversial points were found. First, they didn't have exact explanations about the concentration of hydrochloric acid and the quantity of hydrochloric acid and magnesium in the science textbook and teachers' guide book. Second, the experiment which can show well the nature of dihydrogen was not included because of the safety problem. So this paper presents the ideal condition for the production of dihydrogen and an experimental method to show the nature of dihydrogen. The most ideal condition of dihydrogen production includes 40 mL of 2 molarity hydrochloric acid and 1 g of magnesium. It took 5' 42＆apos; on average to gather two bottles (250 mL) of dihydrogen. In this condition it was possible to reduce the risk of accidents and to economize the materials. This paper proposes the experiment of dihydrogen explosion with a test tube and a film box which is not included in the 7th scince textbook. If teachers show the experiment of dihydrogen explosion with a test tube or film box to students at a class, it will be more interesting for students. And they will be able to help students to understand that dihydrogen can be gathered.

• 조명전기설비학회논문지
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• 제14권4호
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• pp.1-7
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• 2000

본 논문에서 원전의 핵연료 다발의 중섬자속을 측정할 수 있는 노내중성지속 감시계통의 구동모터를 제어하기 위한 스위치의 오동작 원인 분석 및 이 문제를 해결하기 위한 방안을 제시하고자 한다. 노내중성자속 감시계동은 검출기 안내관을 통해 검출기가 노심으로 삽입되거나 인출될 경우 접점선호를 발생하는 기계식 스위치레버를 장착하고 있다. 그러나 기계적인 열화나 환경적인 요인에 의해 기계식 스위치레버의 특성이 점점 변화되어 마침내 잘못된 접점신호를 발생하게 된다. 그러므로 아들 문제 해결을 위해 기계식 스위지 대선 전자식 스위치를 검출기 안내관 밖에 배치하였고, 공진효과를 이용하여 점점신호를 발생하는 회로개선과 소음 및 전기적 방해를 방지하기 위한 콘데서를 전자회로 전원 입력측에 설치하였다. 이러한 개선을 완료한 후, 여러 조건하에서 이 향상된 스위치 제어회로를 반복적으로 시험하였는데, 결국 이를 통해 원하는 접점신호를 얻게되었을 뿐 아니라 발전소 정상운전 중에 관련시스템의 주기시험을 통해서도 검출기 접점 오동작 신호가 발생되지 않음울 확인할 수 있게 되었다.

• 한국수정란이식학회지
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• 제12권1호
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• pp.111-116
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• 1997

The present study was carried out to produce in vitro fertilized embryos with immature follicular oocytes collected by transvaginal aspiration from Holstein cows. A simple aspiration apparatus consists of two stainless steel tubes, an inner tube (needle holder; 1.2cmdiameter, 55cm long) and an outer tube (1.5cm diameter, 4Scm long), and a hand-operated vacuum pump was used. Under epidural anesthesia, the needle guide was passed into the vagina of the cow to a point next to the cervix. An ovary was placed against the wall of the vagina over the end of the aspiration needle by rectal manipulation. As the needlepassed into the ovary, an assistant was asked to apply vacuum(l00mrnHg) and the ovary was manipulated back and forth in all directions over the needle. When all sites of the ovary was aspirated, the needle was withdrawn and the needle guide was moved to the other side of ovary and the procedure was repeated. When the oocyte aspiration procedure was finished, collected fluid was transported to laboratory. Oocytes surrounded with at least 1 layer of cumulus cells were matured, fertilized and cultured in vitro. The results were as follows; Ninety seven oocytes were collected by transvaginal aspiration from seventeen Holstein cows(5.7 /head). The number of oocytes surrounded with at least 1 layer of cumulus cells were 60(61.9%). Following in vitro maturation, fertilization and culture, the cleavage and development rate to morula+blastocyst were 83.3% and 30.0%, respectively. From this study, transferable in vitro fertilized embryos could be produced with imma- ture follicular oocytes collected by transvaginal aspiration from Holstein cows using a simple aspiration apparatus.

• Nuclear Engineering and Technology
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• 제43권2호
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• pp.149-158
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• 2011

Metal waste generated from the pyroprocessing of 10 MtU of spent fuel was classified by comparing the specific activity of a relevant radionuclide with the limit value of the specific activity specified in the Korean acceptance criteria for a lowand intermediate-level waste repository. A Korean Optimized Fuel Assembly design with a 17${\times}$17 array, an initial enrichment of 4.5 weight-percent, discharge burn-up of 55 GWD/MtU, and a 10-year cooling time was considered. Initially, the mass and volume of each structural component of the assembly were calculated in detail, and a source term analysis was subsequently performed using ORIGEN-S for these components. An activation cross-section library generated by the KENO-VI/ORIGEN-S module was utilized for top-end and bottom-end pieces. As a result, an Inconel grid plate, a SUS plenum spring, a SUS guide tube subpart, SUS top-end and bottom-end pieces, and an Inconel top-end leaf spring were determined to be unacceptable for the Gyeongju low- and intermediate-level waste repository, as these waste products exceeded the acceptance criteria. In contrast, a Zircaloy grid plate and guide tube can be placed in the Gyeongju repository. Non-contaminated Zircaloy cladding occupying 76% of the metal waste was found to have a lower level of specific activity than the limit value. However, Zircaloy cladding contaminated by fission products and actinides during the decladding process of pyroprocessing was revealed to have 52 and 2 times higher specific activity levels than the limit values for alpha and $^{90}Sr$, respectively. Finally, it was found that 88.7% of the metal waste from the 17${\times}$17 Korean Optimized Fuel Assembly design should be disposed of in a deep geological repository. Therefore, it can be summarized that separation technology with a higher decontamination factor for transuranics and strontium should be developed for the efficient management of metal waste resulting from pyroprocessing.