• Title/Summary/Keyword: dynamic plasticity

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Local protein synthesis in neuronal axons: why and how we study

  • Kim, Eunjin;Jung, Hosung
    • BMB Reports
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    • v.48 no.3
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    • pp.139-146
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    • 2015
  • Adaptive brain function and synaptic plasticity rely on dynamic regulation of local proteome. One way for the neuron to introduce new proteins to the axon terminal is to transport those from the cell body, which had long been thought as the only source of axonal proteins. Another way, which is the topic of this review, is synthesizing proteins on site by local mRNA translation. Recent evidence indicates that the axon stores a reservoir of translationally silent mRNAs and regulates their expression solely by translational control. Different stimuli to axons, such as guidance cues, growth factors, and nerve injury, promote translation of selective mRNAs, a process required for the axon's ability to respond to these cues. One of the critical questions in the field of axonal protein synthesis is how mRNA-specific local translation is regulated by extracellular cues. Here, we review current experimental techniques that can be used to answer this question. Furthermore, we discuss how new technologies can help us understand what biological processes are regulated by axonal protein synthesis in vivo.

Convergence in Fashion Design (컨버전스 트렌드에 의한 패션 디자인)

  • Ko Hyun-Zin
    • Journal of the Korean Society of Costume
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    • v.56 no.7 s.106
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    • pp.148-162
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    • 2006
  • The purpose of this study is to examine the concept of convergence which is one of the trendy issues as a new digital paradigm of Integrative thinking in 21st century, to analyze the plastic feature and internal meaning of convergence expressed in fashion design, and to grasp the cultural symbolism through this aesthetic analysis. Because there have been considerable discussions on convergence, centering on industrial product area associated with media, I will proceed my study on the basis of them. For this, the documentary study and practical case study have been executed. This study will be helpful to find a direction of future fashion design trend. Convergence in digital stage can be defined as a phenomenon which different functions of product move towards one direction for greater efficiency, and not only as a technical integration between functions of product, but also an extension of area. Convergence can be classified by their use as (1) convergence for convenient daily life (2) convergence with intelligent scientific technology (3) convergence for entertainment on the basis of sensual experience. The plasticity of convergence designs feature as a open dynamic structure which potentiate transformation and their internal meaning can be inquired such qualities as integrative multiplicity, efficiency, mobility, intelligence. Specially convergence fashion design has protection qualify resulting from wearability on body. Ultimately convergence fashion design as a future digital paradigm can be thought as both eco-friendly design and human-centered design from positive technology-based viewpoint, because it is easy to transform according to our environment, convenient to reserve, and efficient to enhance spatial usibility.

Dynamics Simulation of Solid Particles in Compression Deformation of Rheology Material (레오로지 소재의 압축변형시 고상입자 거동의 동역학 해석)

  • Lee, C.S.;Kang, C.G.
    • Transactions of Materials Processing
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    • v.15 no.5 s.86
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    • pp.395-401
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    • 2006
  • It is reported that semi-solid forming process takes many advantages over the conventional forming process, such as a long die life, good mechanical properties and energy saves. It is important to predict the deformation behavior for optimization of the forging process with semi-solid materials and to control liquid segregation for mechanical properties of materials. But rheology material has thixotropic, pseudo-plastic and shear-thinning characteristics. So, it is difficult for a numerical simulation of the rheology process to be performed because complicated processes such as the filling to include the state of the free surface and solidification in the phase transformation must be considered. General plastic or fluid dynamic analysis is not suitable for the analysis of the rheology material behavior. Recently, molecular dynamics is used for the behavior analysis of the rheology material and turned out to be suitable among several methods. In this study, molecular dynamics simulation was performed for the control of liquid segregation, forming velocity, and viscosity in compression experiment as a part of study on the analysis of rheology forming process.

Three-dimensional Reconstruction of Tricuspid Annulus with the Duran Ring (Duran Ring을 이용한 삼천판륜의 삼차원적 재건술)

  • Yoo Dong Gon;Kim Chong Wook;Park Chong Bin;Choo Suk Jung;Lee Jae Won
    • Journal of Chest Surgery
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    • v.38 no.1 s.246
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    • pp.88-90
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    • 2005
  • Tricuspid annuloplasty with the flexible Duran ring may result in a physiologic repair while maintaining the dynamic morphology of the tricuspid annulus. A method for a durable three-dimensional tricuspid annular reconstruction, which retains the plasticity and orifice area of the tricuspid annulus, is described.

Evaluation of seismic assessment procedures for determining deformation demands in RC wall buildings

  • Fox, Matthew J.;Sullivan, Timothy J.;Beyer, Katrin
    • Earthquakes and Structures
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    • v.9 no.4
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    • pp.911-936
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    • 2015
  • This work evaluates the performance of a number of seismic assessment procedures when applied to a case study reinforced concrete (RC) wall building. The performance of each procedure is evaluated through its ability to accurately predict deformation demands, specifically, roof displacement, inter-storey drift ratio and wall curvatures are considered as the key engineering demand parameters. The different procedures include Direct Displacement-Based Assessment, nonlinear static analysis and nonlinear dynamic analysis. For the latter two approaches both lumped and distributed plasticity modelling are examined. To thoroughly test the different approaches the case study building is considered in different configurations to include the effects of unequal length walls and plan asymmetry. Recommendations are made as to which methods are suited to different scenarios, in particular focusing on the balance that needs to be made between accurate prediction of engineering demand parameters and the time and expertise required to undertake the different procedures. All methods are shown to have certain merits, but at the same time a number of the procedures are shown to have areas requiring further development. This work also highlights a number of key aspects related to the seismic response of RC wall buildings that may significantly impact the results of an assessment. These include the influence of higher-mode effects and variations in spectral shape with ductility demands.

Residual seismic performance of steel bridges under earthquake sequence

  • Tang, Zhanzhan;Xie, Xu;Wang, Tong
    • Earthquakes and Structures
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    • v.11 no.4
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    • pp.649-664
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    • 2016
  • A seismic damaged bridge may be hit again by a strong aftershock or another earthquake in a short interval before the repair work has been done. However, discussions about the impact of the unrepaired damages on the residual earthquake resistance of a steel bridge are very scarce at present. In this paper, nonlinear time-history analysis of a steel arch bridge was performed using multi-scale hybrid model. Two strong historical records of main shock-aftershock sequences were taken as the input ground motions during the dynamic analysis. The strain response, local deformation and the accumulation of plasticity of the bridge with and without unrepaired seismic damage were compared. Moreover, the effect of earthquake sequence on crack initiation caused by low-cycle fatigue of the steel bridge was investigated. The results show that seismic damage has little impact on the overall structural displacement response during the aftershock. The residual local deformation, strain response and the cumulative equivalent plastic strain are affected to some extent by the unrepaired damage. Low-cycle fatigue of the steel arch bridge is not induced by the earthquake sequences. Damage indexes of low-cycle fatigue predicted based on different theories are not exactly the same.

Earthquake effects on the energy demand of tall reinforced concrete walls with buckling-restrained brace outriggers

  • Beiraghi, Hamid
    • Structural Engineering and Mechanics
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    • v.63 no.4
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    • pp.521-536
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    • 2017
  • Reinforced concrete core-wall structures with buckling-restrained brace outriggers are interesting systems which have the ability to absorb and dissipate energy during strong earthquakes. Outriggers can change the energy demand in a tall building. In this paper, the energy demand was studied by using the nonlinear time history analysis for the mentioned systems. First, the structures were designed according to the prescriptive codes. In the dynamic analysis, three approaches for the core-wall were investigated: single plastic hinge (SPH), three plastic hinge (TPH) and extended plastic hinge (EPH). For SPH approach, only one plastic hinge is allowed at the core-wall base. For TPH approach, three plastic hinges are allowed, one at the base and two others at the upper levels. For EPH approach, the plasticity can extend anywhere in the wall. The kinetic, elastic strain, inelastic and damping energy demand subjected to forward directivity near-fault and ordinary far-fault earthquakes were studied. In SPH approach for all near-fault and far-fault events, on average, more than 65 percent of inelastic energy is absorbed by buckling-restrained braces in outrigger. While in TPH and EPH approaches, outrigger contribution to inelastic energy demand is reduced. The contribution of outrigger to inelastic energy absorption for the TPH and EPH approaches does not differ significantly. The values are approximately 25 and 30 percent, respectively.

Evaluation of Mechanical Property and Microstructure of Forged and T6-treated 6061 Aluminum Alloy Wheel (자동차 휠용 6061 Al합금의 단조 및 T6 열처리 전후의 미세조직과 기계적 특성 평가)

  • Lee, J.H.;Jeong, H.S.;Yeom, J.T.;Kim, J.H.;Park, N.K.;Lee, Y.T.;Lee, D.G.
    • Transactions of Materials Processing
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    • v.16 no.5 s.95
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    • pp.354-359
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    • 2007
  • Effects of forging and mechanical properties of 6061 aluminum alloy wheel for automobiles were investigated in the present study. Microstructural and tensile characteristics of automobile wheel after hot forging process using dynamic screw press were analyzed to evaluate effect of metal flow on mechanical properties. The results showed advanced mechanical properties of 6061 alloy wheel because of $Mg_2Si$ precipitation by T6, elongated grain by forging, and work hardening by dense metal flow, etc. Hot compression tests were conducted in order to characterize high temperature compression deformation behaviors and microstructural variation in the range of $300{\sim}450^{\circ}C$, in the strain rate range of $10^{-3}{\sim}10^1\;sec^{-1}$. As strain rate increased, maximum compression stress increased but it was shown the reverse linear relation between temperature and maximum stress irrelevant to strain rate variation. On the other hand, temperature and yield stress didn't have any linear relation and its relation showed big deviation by a function of strain rate and test temperature.

Process Design of Isothermal Forging for Three-Dimensional Ti-6Al-4V Wing-Shape (Ti-6Al-4V 합금 3D 날개형상의 항온단조 공정설계)

  • Yeom J. T.;Park N. K.;Lee Y. H.;Shin T. J.;Hong S. S.;Shim I. O.;Hwang S. M.;Lee C. S.
    • Transactions of Materials Processing
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    • v.14 no.2 s.74
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    • pp.126-132
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    • 2005
  • The isothermal forging design of a Ti-6Al-4V wing shape was performed by 3D FE simulation. The design focuses on near-net shape forming by the single stage. The process variables such as the die design, pre-form shape and size, ram speed and forging temperature were investigated. The main design priorities were to minimize forging loads and to distribute strain uniformly in a given forging condition. The FE simulation results for the final process design were compared with the isothermal forging tests. The instability of deformation was evaluated using a processing map based on the dynamic materials model(DMM), including flow stability criteria. Finally, a modified process design for producing a uniform Ti-6Al-4V wing product without forming defects was suggested.

A Study on the Investigation of Space-Construction by Tatlin (타틀린의 공간구축 실험 연구 - ‘반-부조’ 작업(1913-1917)을 중심으로 -)

  • 한귀진
    • Korean Institute of Interior Design Journal
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    • v.13 no.5
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    • pp.66-73
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    • 2004
  • If we consider the origins of new architectural language in Russian, as opposed to its social dimensions, then we are looking at quite another area of pre-Revolutionary activity: art. It was Tatlin's early ‘counter-reliefs’ which first explored the way new materials might generate new artistic form. The Basis of his art is collage and the reality of materials. In 1915, he exhibited the first of his ‘counter-reliefs’, casual montages of pieces of metal that invade the space around them, making the decomposition of the forms three-dimensional. What is not in doubt is the primacy of materials in Tatlin's art. He was a key figure in the transition from art towards design and ‘construction’, the last was accomplished with ‘real materials in real space.’After the October Revolution, one of the central myths of avant-garde was the realization of a total work of art. The progress has developed in the directions to an unprecedented creative realm, situated somewhere between painting and architecture in the post-revolutionary period. Paramount among such pioneer works was Tatlin's design for a monument to the Third International in 1919. Here In an artistic form, his investigation of ‘material, volume and construction’ was clearly embodied. In the comtemporary architecture, Tatlin's concept has been a great influence on the various tendencies of spatial expressions. For example, the architecture with concept of ex-formality has many varied aspects of space composition - dynamic forms with plasticity of concrete, ex-cubic composition with free walls, disposal composition by geometric collision and superimposition, and etc.