• Title/Summary/Keyword: Closed-Structure

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Status and Problems of Closed-Loop Supply Chain of Traditional Power Battery in China

  • Chen, Jinhui;Bayarsaikhan, Bayarsaikhan;Nam, Sootae;Jin, Chanyong
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2021.10a
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    • pp.567-569
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    • 2021
  • The power battery supply chain in China currently lacks stable cooperation and effective information exchange. The competitive pressure brings about irregular recycling channels, reducing the operation and efficiency of the power battery supply chain. Besides, some regular power battery recycling enterprises fabricate data to obtain subsidies by taking advantage of the loopholes in the relevant policies of the state on recycling subsidies. Due to the high price of recycling in the black market, some regular enterprises resell the batteries recycled through regular channels, later purchasing the batteries with no utilization value to obtain the national recycling subsidies by cheating at the same time. Fig. 3 shows the present network structure of the tradi tional Chinese power battery closed-loop supply chain

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Bridges dynamic analysis under earthquakes using a smart algorithm

  • Chen, Z.Y.;Meng, Yahui;Wang, Ruei-yuan;Chen, Timothy
    • Earthquakes and Structures
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    • v.23 no.4
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    • pp.329-338
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    • 2022
  • This work addresses the optimization controller design problem combining the AI evolution bat (EB) optimization algorithm with a fuzzy controller in the practical application of a reinforced concrete frame structure. This article explores the use of an intelligent EB strategy to reduce the dynamic response of Lead Rubber Bearing (LRB) composite reinforced concrete frame structures. Recently developed control units for plant structures, such as hybrid systems and semi-active systems, have inherently non-linear properties. Therefore, it is necessary to develop non-linear control methods. Based on the relaxation method, the nonlinear structural system can be stabilized by properly adjusting the parameters. Therefore, the behavior of a closed-loop system can be accurately predicted by determining the behavior of a closed-loop system. The performance and durability of the proposed control method are demonstrated by numerical simulations. The simulation results show that the proposed method is a viable and feasible control strategy for seismically tuned composite reinforced concrete frame structures.

Structure-Control Combined Design with Structure Intensity

  • PARK JUNG-HYEN;KIM SOON HO
    • Journal of Ocean Engineering and Technology
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    • v.17 no.5 s.54
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    • pp.57-65
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    • 2003
  • This paper proposes an optimum design method of structural and control systems, using a 2-D truss structure as an example. The structure is subjected to initial static loads and disturbances. For the structure, a FEM model is formed. Using modal transformation, the equation of motion is transformed into modal coordinates, in order to decrease D.O.F. of the FEM model. To suppress the effect of the disturbances, the structure is controlled by an output feedback $H_{\infty}$ controller. The design variables of the combined optimal design of the control-structure systems are the cross sectional areas of truss members. The structural objective function is the structural weight. The control objective function is the $H_{\infty}$ norm, the performance index of control. The second structural objective function is the energy of the response related to the initial state, which is derived from the time integration of the quadratic form of the state in the closed-loop system. In a numerical example, simulations have been perform. Through the consideration of structural weight and $H_{\infty}$ norm, an advantage of the combined optimum design of structural and control systems is shown. Moreover, since the performance index of control is almost nearly optimiz, we can acquire better design of structural strength.

Structure-Control Combined Design with Structure Intensity

  • Park, Jung-Hyen;Kim, Soon-Ho
    • International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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    • v.6 no.1
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    • pp.60-68
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    • 2003
  • This paper proposes an optimum design method of structural and control systems, using a 2-D truss structure as an example. The structure is subjected to initial static loads and disturbances. For the structure, a FEM model is formed. Using modal transformation, the equation of motion is transformed into modal coordinates, in order to decrease D.O.F. of the FEM model. To suppress the effect of the disturbances, the structure is controlled by an output feedback $H_{\infty}$ controller. The design variables of the combined optimal design of the control-structure systems are the cross sectional areas of truss members. The structural objective function is the structural weight. The control objective function is the $H_{\infty}$ norm, the performance index of control. The second structural objective function is the energy of the response related to the initial state, which is derived from the time integration of the quadratic form of the state in the closed-loop system. In a numerical example, simulations have been perform. Through the consideration of structural weight and $H_{\infty}$ norm, an advantage of the combined optimum design of structural and control systems is shown. Moreover, since the performance index of control is almost nearly optimiz, we can acquire better design of structural strength.

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Design Method Development of Smart TMD for Retractable-Roof Spatial Structure (개폐식 대공간 구조물을 위한 스마트 TMD 설계기법 개발)

  • Kim, Hyun-Su;Kang, Joo-Won
    • Journal of Korean Association for Spatial Structures
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    • v.17 no.3
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    • pp.107-115
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    • 2017
  • In this paper, a structural design method of a smart tuned mass damper (TMD) for a retractable-roof spatial structure under earthquake excitation was proposed. For this purpose, a retractable-roof spatial structure was simplified to a single degree of freedom (SDOF) model. Dynamic characteristics of a retractable-roof spatial structure is changed based on opened or closed roof condition. This condition was considered in the numerical simulation. A magnetorheological (MR) damper was used to compose a smart TMD and a displacement based ground-hook control algorithm was used to control the smart TMD. The control effectiveness of a smart TMD under harmonic and earthquake excitation were evaluated in comparison with a conventional passive TMD. The vibration control robustness of a smart TMD and a passive TMD were compared along with the variation of natural period of a simplified structure. Dynamic responses of a smart TMD and passive TMD under resonant harmonic excitation and earthquake load were compared by varying mass ratio of TMD to total mass of the simplified structure. The design procedure proposed in this study is expected to be used for preliminary design of a smart TMD for a retractable-roof spatial structure.

Design of silicon-on-nothing structure based on multi-physics analysis

  • Song, Jihwan;Zhang, Linan;Kim, Dongchoul
    • Multiscale and Multiphysics Mechanics
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    • v.1 no.3
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    • pp.225-231
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    • 2016
  • The formation of silicon-on-nothing (SON) structure during an annealing process from the silicon substrate including the trench structures has been considered as an effective technique to construct the structure that has an empty space under the closed flat surface. Previous studies have demonstrated the mechanism of the formation of SON structure, which is based on the surface diffusion driven by the minimization of their surface energy. Also, it has been fragmentarily shown that the morphology of SON structure can be affected by the initial design of trench (e.g., size, number) and the annealing conditions (e.g., temperature, pressure). Based on the previous studies, here, we report a comprehensive study for the design of the cavity-embedded structure (i.e., SON structure). To do this, a dynamic model has been developed with the phase field approach. The simulation results represent that the morphology of SON structures could be detailedly designed, for example the position and thickness of cavity, the thickness of top and bottom layer, according to the design parameters. This study will give us an advantage in the effective design of SON structures.

Effect of Gaps on Species Diversity in the Naturally Regenerated Mixed Broadleaved-Korean Pine Forest of the Xiaoxing'an Mountains, China

  • Jin, Guangze;Liu, Yanyan;Liu, Shuang;Kim, Ji-Hong
    • Journal of Ecology and Environment
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    • v.30 no.4
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    • pp.325-330
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    • 2007
  • Recognizing the ecological importance of forest gap formation for forest community structure, we examined the differences in species diversity between forest gaps and closed canopy areas for trees and shrubs in three developmental stages (seedling, sapling I, and sapling II) in a typical mixed broadleaved-Korean pine forest. We randomly placed 100 sample plots ($2{\times}2m$ for seedling and sapling I, and $5{\times}5m$ for sapling II) in forest gap and closed canopy areas of a 9 ha permanent sample plot for vegetation surveys of plants of each developmental stage in each habitat type. Even though the formation of forest gaps encouraged the occurrence of gap-dependent species and increased overall species diversity, there were no significant differences in species richness among the three developmental stages for both tree and shrub species (p>0.05). Comparing the two types of sites, statistical tests revealed no difference in species richness for trees, but highly significant differences (p<0.01) between forest types for shrubs for seedlings and sapling I, but not sapling II. Analysis of variance test indicated that there were no significant differences in species diversity among the three developmental stages of tree species (p>0.05) for both Simpson and Shannon indices. The variance for shrub seedlings was significantly different between forest gaps and closed canopy areas, but not for sapling I and sapling II. The analysis showed that the species diversity in forest gaps was significantly different from that of closed canopy areas for seedling and sapling I (p<0.01), but not for sapling II (p>0.05).

A retrospective clinical investigation for the effectiveness of closed reduction on nasal bone fracture

  • Kang, Byung-Hun;Kang, Hyo-Sun;Han, Jeong Joon;Jung, Seunggon;Park, Hong-Ju;Oh, Hee-Kyun;Kook, Min-Suk
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.41
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    • pp.53.1-53.6
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    • 2019
  • Background: The nasal bone is the most protruding bony structure of the facial bones. Nasal bone fracture is the most common facial bone fracture. The high rate of incidence of nasal bone fracture emphasizes the need for systematical investigation of epidemiology, surgical techniques, and complications after surgery. The objective of this study is to investigate the current trends in the treatment of nasal bone fractures and the effectiveness of closed reduction depending on the severity of the nasal bone fracture. Patients and methods: A total of 179 patients with a nasal bone fracture from 2009 to 2017 were enrolled. Their clinical examination, patient's records, and radiographic images of nasal bone fractures were evaluated. Results: Patients ranged from children to elderly. There were 156 (87.2%) males and 23 (12.8%) females. Traffic accident (36.9%) was the most common cause of nasal fracture. Orbit fracture (44 patients, 24.6%) was the most common fracture associated with a nasal bone fracture. Complications after surgery included postoperative deformity in 20 (11.2%) patients, nasal obstruction in 11 (6.1%) patients, and olfactory disturbances in 2 (1.1%) patients and patients with more severe nasal bone fractures had higher rates of these complications. Conclusion: Closed reduction could be performed successfully within 2 weeks after injury.

The Effect of the Fill Charge Ratio on the Heat Transfer Characteristics of a Two-Phase Closed Thermosyphon (충전율의 변화가 밀폐형 2-상 열사이폰의 열전달 특성에 미치는 영향에 관한 연구)

  • Park, Yong-Joo;Hong, Sung-Eun;Kim, Chul-Ju
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.26 no.12
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    • pp.1646-1654
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    • 2002
  • A two-phase closed thermosyphon was one of the most effective devices in the removing heat because of its simple structure, thermal diode characteristics, wide operating temperature range and so on. In this study, a two-phase closed thermosyphon(working fluid PFC(C6F14), container copper(inner grooved surface)) was fabricated with a reservoir which can change the fill charge ratio. The experiments were performed in the range of 50~600W heat flow rate and 10~70% fill charge ratio. The results were compared with some correlations that were presented by Rohsenow and Immura et al. in the evaporator, by Nusselt, Gross and Uehara et al. in the condenser and by Cohen and Bayley, Wallis, Kutateladze and Faghri et al. in heat transfer limitation etc.. The heat transfer coefficient at the evaporator increased with the input power. However the effect of the fill charge ratio was nearly negligible. At the condenser, it showed an opposite trend to the evaporator and with increase of the fill charge ratio, showed some enhancement of heat transfer. The heat transport limitation was occurred by the dry-out limitation for small fill charge ratio(10%) and presented about 100W. For the case of large fill charge ratio(Ψ$\geq$40%), it was occurred by the flooding limitation at about 500W.

Assessment of Ultimate Bearing Capacity for an Embedded Wall by Closed-Form Analytical Solution (근사적인 해석법에 의한 근입된 벽체의 극한지지력 평가)

  • Lee, Yong-Joo
    • Journal of the Korean Geotechnical Society
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    • v.22 no.9
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    • pp.23-36
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    • 2006
  • This study presents the development of a new closed-form analytical solution for the ultimate bearing capacity of an embedded wall in a granular mass. The closed-form analytical solution consists of upper and lower bound solutions (UB and LB). The calculated values from these bound solutions were compared with the author's two-dimensional laboratory wall model loading test and finite element analysis in the plastic region. The comparison showed that ultimate bearing loads from both the model test and finite element analysis are located between UB and LB. In particular, the ultimate bearing load from LB showed good agreement with the ultimate bearing load values from both the model test and finite element analysis. However, the calculated value from the conventional empirical form subjected to plane-strain conditions was shown to be much smaller than the LB.