• 한국구조물진단유지관리공학회 논문집
• /
• 제12권5호
• /
• pp.116-124
• /
• 2008

본 연구에서는 원형수직구 굴착에 따른 Ring Beam의 거동을 평가하기 위하여 현장계측 자료의 분석과 평가, 굴착심도 변화에 따른 Ring Beam의 응력 특성 등의 비교분석을 구조해석에 기초하여 평가하였다. 그 결과, Ring Beam의 거동은 현장계측 및 구조해석 결과에서 유사한 경향을 나타내는 것을 알 수 있었다. 이로부터 굴착심도 변화에 따른 Ring Beam 거동은 본 연구에서 제안한 구조해석에 의해 예측할 수 있는 것을 확인하였다.

• 한국터널지하공간학회 논문집
• /
• 제14권1호
• /
• pp.55-77
• /
• 2012

현대식 Rock TBM공법은 TBM에 의한 굴착과 지반 타입에 따른 능동적인 지보가 어우러진 공법으로 세그먼트를 사용하지 않고 숏크리트, 링빔, 록볼트, 와이어매쉬 등의 지보재에 의해 터널을 지보한다. 현대식 Rock TBM에서 사용되는 링빔은 H-형강을 사용하여 NATM의 강지보재와 유사하나 원형으로 완전히 폐합되어 설치됨에 따라 강지보재보다 더 효과적이다. 따라서 현대식 Rock TBM에서 링빔은 터널의 안정성 향상에 기여하는 바가 크며, 본 연구에서 소개하는 가압형 링빔(pressurized ring beam)은 그 효과를 더욱 향상 시킬 수 있다. 가압형 링빔의 효과를 검증하기 위해 3차원 수치해석을 수행하였으며 그 결과 최소주응력 증가, 과대변위를 발생시키는 소성변형률의 감소, 링빔 설치 후 발생하는 변위인 상대변위감소 그리고 링빔 간격 증가 효과를 확인하였다.

• 제어로봇시스템학회논문지
• /
• 제17권2호
• /
• pp.79-87
• /
• 2011

This paper presents the optimal design of an overlapped ultrasonic sensor ring for high resolution obstacle detection of an autonomous mobile robot. It is assumed that a set of low directivity ultrasonic sensors of the same type are arranged along a circle of nonzero radius at a regular spacing with their beams overlapped. First, taking into account the dead angle region, the entire range of obstacle detection is determined with reference to the center of an overlapped ultrasonic sensor ring. Second, the optimal design index of an overlapped ultrasonic sensor ring is defined as the area closeness of three sensing subzones resulting from beam overlap. Third, the lower and upper bounds on the number of ultrasonic sensors are derived, which can guarantee minimal beam overlap and also avoid excessive beam overlap among adjacent ultrasonic sensors. Fourth, employing a commercial low directivity ultrasonic sensor, an optimal design example of an overlapped ultrasonic sensor ring is given along with the ultrasonic sensor ring prototype mounted on top of a mobile robot. Finally, some experimental results using our prototype ultrasonic sensor ring are given to demonstrate the validity and performance of an optimally overlapped ultrasonic sensor ring for high resolution obstacle detection.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1997년도 하계학술대회 논문집 E
• /
• pp.1779-1781
• /
• 1997

The 2.0 GeV Pohang Light Source (PLS) is consisted of a full energy Linac and a storage ring. Four kicker magnets are installed in the storage ring tunnel to move the stored beam orbit in the storage ring closer to the injected beam from the beam transfer line. The injected beam then falls into the storage ring beam dynamic aperture. A kicker magnet modulator drives all four kicker magnets to maintain field balance and also synchronized kick of the beam. The kicker modulator can handle 2 GeV full energy beam. The kicker magnet modulator is installed in the storage ring tunnel and under stable operation. Specification of the kicker magnet modulator is ${\sim}6.0{\mu}s$ pulse-width, 200 ns flat-top width with ${\pm}0.2%$ regulation, ${\sim}24\;kA$ peak current, and 10 Hz repetition rate. Two thyratron switches (EEV CX-1536AX) are used in the system. In this article, design, and experimental results of the kicker magnet modulator are discussed.

• IEIE Transactions on Smart Processing and Computing
• /
• 제4권6호
• /
• pp.384-390
• /
• 2015

There are two main artifacts in reconstructed images from in-beam positron emission tomography (PET). Unlike generic PET, in-beam PET uses the annihilation photons that occur during heavy ion therapy. Therefore, the geometry of in-beam PET is not a full ring, but a partial ring that has one or two openings around the rings in order for the hadrons to arrive at the tumor without prevention of detector blocks. This causes truncation in the projection data due to an absence of detector modules in the openings. The other is a ring artifact caused by the gaps between detector modules also found in generic PET. To sum up, in-beam PET has two kinds of gap: openings for hadrons, and gaps between the modules. We acquired three types of simulation results from a PET system: full-ring, C-ring and dual head. In this study, we aim to compensate for the artifacts that come from the two types of gap. In the case of truncation, we propose a method that uses prior knowledge of the location where annihilations occur, and we applied the discrete-cosine transform (DCT) gap-filling method proposed by Tuna et al. for inter-detector gap.

• Nuclear Engineering and Technology
• /
• 제56권2호
• /
• pp.485-497
• /
• 2024

Ring beam is the main anchorage zone of the tendons in the nuclear power prestressed concrete containment vessel (PCCV). Its safety is crucial and has a great influence on the overall performance of PCCV. In this paper, two half-scale ring beams were tested to investigate the mechanical performance of the anchorage zone in the PCCV under multidirectional pressure. The effect of working condition with different tension sequences was investigated. Additionally, a half axisymmetric plane model of the containment was established by the finite element simulation to further predict the experimental responses and propose the local reinforcement design in the anchorage zone of the ring beam. The results showed that the ultimate load of the specimens under both working conditions was greater than the nominal ultimate tensile force. The original reinforcement design could meet the bearing capacity requirements, but there was still room for optimization. The ring beam was generally under pressure in the anchorage area, while the splitting force appeared in the under-anchor area, and the spalling force appeared in the corner area of the tooth block, which could be targeted for local strengthening design.

• 콘크리트학회논문집
• /
• 제22권6호
• /
• pp.817-824
• /
• 2010

약 콘크리트 격납구조물은 구조적 안전성이 뛰어나고 경제적이므로 원자력발전소 격납건물, LNG 저장탱크 등에 널리 사용되고 있다. 격납구조물 중 지붕 돔의 형태는 구조적 안전성, 물량 및 시공 난이도에 큰 영향을 미치므로 최적의 두께와 곡률을 도출하고자 하는 노력이 필요하다. 한편 일반적으로 PSC 구조로 설계되는 링빔은 이러한 돔을 지지하여 벽체의 변형을 최소화시키는 역할을 하며, 단면 크기와 더불어 프리스트레스 수준을 적절히 결정하는 것이 설계의 핵심이 된다. 이 연구에서는 축대칭 회전쉘의 막이론을 적용하여 본설계 시의 유한요소해석에 앞서 돔과 링빔의 초기 형상이나 프리스트레스 수준을 효율적으로 결정할 수 있는 기법을 제안하였다. 이러한 기법을 국내에서 시공된 격납구조물의 돔과 링빔에 적용하여 분석하고 단면 형상이나 프리스트레싱 설계에 대한 개선 방안을 고찰하였다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
• /
• pp.139-140
• /
• 2010

콘크리트 격납구조물의 돔과 링빔은 서로 접합된 상태로 단면력 분포에 있어 상호 영향을 미치기 때문에 연계 해석이 필요하다. 이 연구에서는 축대칭 회전쉘의 막이론을 적용하여 본설계시의 유한요소해석에 앞서 돔과 링빔의 초기 형상이나 링빔의 프리스트레스 수준을 효율적으로 결정할 수 있는 기법을 제안하였다.

• 한국농공학회지
• /
• 제35권1호
• /
• pp.59-66
• /
• 1993

Ring Sector Plate Supported by Elastic Beam Although all the reinforced concrete circular ring sector plates are elastically supported, it is conventional to simplify their supporting conditions as fixed or simply-supported ones assuming that their supporting beam has infinite stiffness. However, in order to obtain a precise solution, it should be required to consider the stiffness of their supporting beam. As a methodological improvement to the precise analysis, "Reinforced Concrete Model" previously developed by the author was applied to the structural analysis of the reinforced concrete circular ring sector plates with elastically supported beam. The results of analysis in the cases under various conditions of open angle, steel ratio, relative stiffness(EI/DL) between plate and supporting beam were summarized as follows ; 1.Although the effect of relative stiffness between plate and supporting beam varies depending on the magnitude of open angle, in general, it shows the largest when not more than 5.0 and negligible when not less than 10.0. Therefore, it would be considered as fixed supporting condition :in the case of its open angle of 0$^{\circ}$rectangular plates), its stiffness ratio being not less than 10.0 and in the other case of its open angle of 30$^{\circ}$, its stiffness ratio being not less than 5.0. 2.In the rectangular plates, the effect of steel ratio is considerable in no supporting condition, but neglible in the supporting condition. So, the effect of steel ratio should be negligible in the case of the elastically supported circular ring sector plates. 3.However, the effect of steel ratio is much more considerable in the case of the fixed supported circular plates, especially, when steel ratio being not more than 1.0% and stiffness ratio being smaller. So, the effect of steel ratio should be considered in the analysis of reinforced concreate circular ring sector plates with fixed conditions. 4.The effect of open angle is greater in the case of without-supporting beam conditions. However, in the other case of with-supporting beam conditions, the effect is a little bit when open angle of not more than 300 and negligible when open angle of not more than 30$^{\circ}$.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2009년도 제38회 동계학술대회 초록집
• /
• pp.325-325
• /
• 2010

The beam position monitor (BPM) in the storage ring measures the position of electron beam with pickup electrodes which are coupled in capacitive way to the electron beam. However, some of the BPM in the PLS storage ring suffer the vertical noise signal at the operation frequency of about 500 MHz, so the pick-up frequency of these BPM is change to 375 MHz. In this study, it is experimentally proved in the PLS beam chamber that the BPM noise is caused by the TE mode excited in the beam chamber.