• Nuclear Engineering and Technology
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• 제30권2호
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• pp.91-98
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• 1998

Time history analysis is usually performed to characterize the nonlinear seismic behavior of a spent fuel storage rack(SFSR). In the past, the seismic analyses of the SFSR were performed with two-dimensional planar models, which could not account for torsional response and simultaneous multi-directional seismic input In this study, three-dimensional seismic analysis methodology is developed for the single SFSR using the ANSYS code. The 3D- Model can be used to determine the nonlinear behavior of the rack, i.e., sliding, uplifting, and impact evaluation between the fuel assembly and rack, and rack and the pool wall, This paper also reviews the 3-D modeling of the SFSR and the adequacy of the ANSYS for the seismic analysis. AS a result of the adquacy study, the method of ANSYS transient analysis with acceleration time history is suitable for the seismic analysis of highly nonlinear structure such as an SFSR but it isn't appropriate to use displacement time history of seismic input.

• Nuclear Engineering and Technology
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• 제39권4호
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• pp.249-256
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• 2007

Light water reactors operated under supercritical pressure conditions have been selected as one of the promising future reactor concepts to be studied by the Generation IV International Forum. Whereas the steam cycle of such reactors can be derived from modem fossil fired power plants, the reactor itself, and in particular the reactor core, still need to be developed. Different core design concepts shall be described here to outline the strategy. A first option for near future applications is a pressurized water reactor with $380^{\circ}C$ core exit temperature, having a closed primary loop and achieving 2% pts. higher net efficiency and 24% higher specific turbine power than latest pressurized water reactors. More efficiency and turbine power can be gained from core exit temperatures around $500^{\circ}C$, which require a multi step heat up process in the core with intermediate coolant mixing, achieving up to 44% net efficiency. The paper summarizes different core and assembly design approaches which have been studied recently for such High Performance Light Water Reactors.

• Smart Structures and Systems
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• 제24권2호
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• pp.193-207
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• 2019

This study concerns with morphing structures, e.g. as applied in the aerospace industry. A morphing aerofoil structure capable of variable geometry was developed, which was shown to be able to cater for the different aerodynamic requirements at different stages of flight. In this work, the useful and relatively simple method has been applied, which provides a direct method for calculating required morphing shape displacements via finding the most effective bar through calculating bar sensitivity to displacement and calculating set of length actuations for bar assembly to control/adjust shape imperfection of prestressable structural assemblies including complex elements ("macro-elements", e.g., the pantographic element), involving Matrix Condensation. The technique has been verified by experiments on the physical model of an aerofoil shaped morphing pantographic structure. Overall, experimental results agree well with theoretical prediction. Furthermore, the technique of multi-iteration adjustment was presented that effective in eliminating errors that occur in the practical adjustment process itself. It has been demonstrated by the experiments on the physical model of pantographic morphing structure. Finally, the study discusses identification of the most effective bars with the objective of minimal number of actuators or minimum actuation.

• Journal of Ceramic Processing Research
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• 제19권6호
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• pp.525-529
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• 2018

The antireflective (AR) coated poly methyl methacrylate (PMMA) substrate was deposited by atomic layer deposition (ALD) on a self-assembled monolayer (SAM) to improve hydrophobicity and mechano-chemical properties of organic thin films. The water contact angles (WCA) were tested to characterize the surface wettability of SAM octadecyltrichlorosilane (OTS) films. Results showed that a contact angle of $105.9^{\circ}$ was obtained for the SAM films with an annealing process, and the highest WCA of $120^{\circ}$ was achieved for the films prepared by the SAM and ALD multi-process. The surface morphology of the SAM films with different assembly times and varying number of ALD cycles was obtained by atomic force microscopy (AFM). The maximum light transmittance for the SAM films on the PMMA substrate reached 99.9% at a wavelength of 450 nm. It was found that the SAM surfaces were not affected at all by the ALD process.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2001년도 추계학술대회 및 정기총회
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• pp.110-110
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• 2001

Histone deacetylase(HDAC), a neuclear enzyme that regulates gene trascription and the assembly of newly synthesized chromatin, has received much attention in recent literature. The explosion of activity in this field has yielded the cloning of a mammalian gene which encodes a complementary histone acetyl trasferases. Several cyclic tetrapeptide inhibitors of HDAC has been reported to affect the hyperacetylation of mammalian and plant histones. Apicidin, a natural product HDAC inhibitor recently isolated at Merck Research Laboratories, induces therapeutic applications as a broad spectrum antiprotozoal agent to multi-drug resistant malaria and a potential antitumor agnet. The biological activity of apicidin appears to be attributable to inhibition of apicocomplexan HDAC at low nanomolar concentrations.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.335-340
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• 2005

In many urban cities, mixed-use development is becoming increasingly essential for the creation of an attractive and sustainable environment that promotes economic vitality, social equity and environmental quality. Due to the differences in scale, scope and intent, certain aspects within the project delivery process of mixed-use are not the same as "conventional" single-use projects. The objective of this paper is to highlight these aspects. Two cases in Southeast Asia serve to illustrate the uniqueness and challenges of mixed-use. In conclusion, the differences between mixed-use and single-use are evident in terms of the diversity of team members, the necessity of multiple market analyses, and a multi-layer (versus single-source) financing structure. Finally, issues concerning ownership tangles, land assembly, planning and application procedures, investment criteria of institutions have been identified as major pitfalls.

• Journal of Information Technology Applications and Management
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• 제19권1호
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• pp.37-46
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• 2012

The scheduling problem of large products like ships, airplanes, space shuttles, assembled constructions, and automobiles is very complex in nature. To reduce inherent computational complexity, we often design scheduling systems that the original problem is decomposed into small sub-problems, which are scheduled independently and integrated into the original one. Moreover, the steep growth of communication technology and logistics makes it possible to produce a lot of multi-nation corporation by which products are produced across more than one plant. Therefore vertical and lateral coordination among decomposed scheduling systems is necessary. In this research, we suggest an agent-based coordinating mechanism for multi-level scheduling systems in supply chain. For design of a general coordination mechanism, at first, we propose a grammar to define individual scheduling agents which are responsible to their own plants, and a meta-level coordination agent which is engaged to supervise individual scheduling agents. Second, we suggest scheduling agent communication protocols for each scheduling agent topology which is classified according to the system architecture, existence of coordinator, and direction of coordination. We also suggest a scheduling agent communication language which consists of three layers : Agent Communication Layer, Scheduling Coordination Layer, Industry-specific Layer. Finally, in order to improve the efficiency of communication among scheduling agents we suggest a rough capacity coordination model which supports to monitor participating agents and analyze the status of them. With this coordination mechanism, we can easily model coordination processes of multiple scheduling systems. In the future, we will apply this mechanism to shipbuilding domain and develop a prototype system which consists of a dock-scheduling agent, four assembly-plant-scheduling agents, and a meta-level coordination agent. A series of experiment using the real-world data will be performed to examine this mechanism.

• 한국측량학회지
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• 제20권3호
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• pp.243-253
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• 2002

최근 들어 수치사진측량은 산업분야를 비롯한 여러 분야에 그 활용범위가 확대되면서 측정정확도의 향상을 위한 다각적인 연구가 진행되고 있으며 그중 다중영상을 이용한 해석방법은 많은 연구자들로 하여금 관심을 모으고 있다. 그러나 이 방법은 영상획득의 용이성과 높은 해석정확도의 확보가 가능한 반면 처리데이터양의 증가로 많은 처리시간과 노력을 요하게 되므로 처리과정의 자동화를 통한 작업의 효율성 향상을 기하여야 한다. 이에 본 연구에서는 정밀시공이 요구되는 전파망원경에 대해 다중영상을 획득하여 이를 해석하기 위한 영상해석과정의 자동화를 구현하고 대상물에 대한 정밀 측정 및 정확도 향상을 꾀하고자 하였다. 연구결과 정밀한 측정을 요하는 대상물에 대해 다중영상해석을 통한 정확도 향상을 도모할 수 있었으며 이를 토대로 전파망원경의 정밀 측정 및 곡률산출을 수행하여 대상물의 시공 후 조립정확도를 검사할 수 있었다.

• 대한화장품학회지
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• 제44권4호
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• pp.399-405
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• 2018

다층 및 다중구획 하이드로젤을 설계하여 4D 마스크팩 적용을 위한 자가접힘 특성분석을 수행하였다. 온도민감성 분자를 하이드로젤에 도입하여 팽창비가 다른 두 층으로 구성된 하이드로젤을 제조하였다. 나아가 팽창비 차이를 조절하여 자가접힘 정도가 다른 삼중구획 하이드로젤을 설계하였다. 상온에서 각각 0.03, 0, $0.03mm^{-1}$의 곡률을 갖는 구획화된 하이드로젤은 피부 온도에서 1.33, 0, $1.33mm^{-1}$의 곡률로 변화하여, 안면 밀착성이 현저히 높아지는 것을 확인하였다. 다층 및 다중구획 하이드로젤 제조 기술은 안면의 부위별 굴곡모양에 따라 자가변환이 가능한 맞춤형 4D 마스크팩 구현에 활용될 수 있다.

• Structural Engineering and Mechanics
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• 제81권4호
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• pp.411-428
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• 2022

This paper presents the Campbell diagram analysis of the rotordynamic system using the full order model (FOM) and the reduced order model (ROM) techniques to determine the critical speeds, identify the stability and reduce the computational time. Due to the spin-speed-dependent matrices (e.g., centrifugal stiffening matrix), several model order reduction (MOR) techniques may be considered, such as the modal superposition (MS) method and the Krylov subspace-based MOR techniques (e.g., Ritz vector (RV), quasi-static Ritz vector (QSRV), multifrequency quasi-static Ritz vector (MQSRV), multifrequency/ multi-spin-speed quasi-static Ritz vector (MMQSRV) and the combined Ritz vector & modal superposition (RV+MS) methods). The proposed MMQSRV method in this study is extended from the MQSRV method by incorporating the rotational-speed-dependent stiffness matrices into the Krylov subspace during the MOR process. Thus, the objective of this note is to respond to the question of whether to use the MS method or the Krylov subspace-based MOR technique in establishing the Campbell diagram of the shaft-disc-blade assembly systems in three-dimensional (3D) finite element analysis (FEA). The Campbell diagrams produced by the FOM and various MOR methods are presented and discussed thoroughly by computing the norm of relative errors (ER). It is found that the RV and the MS methods are dominant at low and high rotating speeds, respectively. More precisely, as the spinning velocity becomes large, the calculated ER produced by the RV method is significantly increased; in contrast, the ER produced by the MS method is smaller and more consistent. From a computational point of view, the MORs have substantially reduced the time computing considerably compared to the FOM. Additionally, the verification of the 3D FE rotordynamic model is also provided and found to be in close agreement with the existing solutions.