• 제목/요약/키워드: cyclic structure

검색결과 917건 처리시간 0.03초

Synthesis of Cyclic Antifreeze Glycopeptide and Glycopeptoids and Their Ice Recrystallization Inhibition Activity

  • Ahn, Mija;Murugan, Ravichandran N.;Shin, Song Yub;Kim, Eunjung;Lee, Jun Hyuck;Kim, Hak Jun;Bang, Jeong Kyu
    • Bulletin of the Korean Chemical Society
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    • 제33권11호
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    • pp.3565-3570
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    • 2012
  • Until now, few groups reported the antifreeze activity of cyclic glycopeptides; however, the tedious synthetic procedure is not amenable to study the intensive structure activity relationship. A series of N-linked cyclic glycopeptoids and glycopeptide have been prepared to evaluate antifreeze activity as a function of peptide backbone cyclization and methyl stereochemical effect on the rigid Thr position. This study has combined the cyclization protocol with solid phase peptide synthesis and obtained significant quantities of homogeneous cyclic glycopeptide and glycopeptoids. Analysis of antifreeze activity revealed that our cyclic peptide demonstrated RI activity while cyclic glycopeptoids showed no RI activity. These results suggest that the subtle changes in conformation and Thr orientation dramatically influence RI activity of N-linked glycopeptoids.

Rotational capacity of H-shaped steel beams under cyclic pure bending

  • Jia, Liang-Jiu;Tian, Yafeng;Zhao, Xianzhong;Tian, Siyuan
    • Steel and Composite Structures
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    • 제30권2호
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    • pp.123-140
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    • 2019
  • This paper presents experimental study on effects of width-to-thickness ratio and loading history on cyclic rotational capacity of H-shaped steel beams subjected to pure bending. Eight Class 3 and 4 H-shaped beams with large width-to-thickness ratios were tested under four different loading histories. The coupling effect of local buckling and cracking on cyclic rotational capacity of the specimens was investigated. It was found that loss of the load-carrying capacity was mainly induced by local buckling, and ductile cracking was a secondary factor. The width-to-thickness ratio plays a dominant effect on the cyclic rotational capacity, and the loading history also plays an important role. The cyclic rotational capacity can decrease significantly due to premature elasto-plastic local buckling induced by a number of preceding plastic reversals with relative small strain amplitudes. This result is mainly correlated with the decreasing tangent modulus of the structural steel under cyclic plastic loading. In addition, a theoretical approach to evaluate the cyclic rotational capacity of H-shaped beams with different width-to-thickness ratios was also proposed, which compares well with the experimental results.

단조 증가 및 반복 하중을 받는 철근 콘크리트 구조물의 탄소성 거동에 대한 해석적 연구 (An Analytical Study on the Elasto-Plastic Behavior of Reinforced Concrete Structure under Monotonic & Cyclic Load)

  • 김화중;박정민;마은희
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 1993년도 가을 학술발표회논문집
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    • pp.131-138
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    • 1993
  • To analysis machanical behavior for RC frame under monotonic & Cyclic load, it is needed to investigate elasto-plastic behavior for steel & concrete. Therefore, in this study, we idealized material model(steel and concrete) to take into account elasto-plastic, limit state, and developed structural analysis program that consider complex non-linearity. We investigated simple beam and portal frame under cyclic & monotonic loading, so we confirmed the propriety.

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A Cyclic CMOS Time-to-Digital Converter

  • Choi, Jin-Ho;Kim, Ji-Hong
    • Journal of information and communication convergence engineering
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    • 제5권2호
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    • pp.112-115
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    • 2007
  • A CMOS TDC(time-to-digital converter) is proposed which has a simple cyclic structure. The proposed TDC consists of pulse-shrinking elements, D latches and D flip-flops. The operation is based on pulse-shrinking of the input pulse. The resolution of digital output can be easily improved by increasing the number of the pulse-shrinking elements, D latches and D flip flops. The TDC performance is improved in viewpoints of power consumption and chip area. Simulation results are shown to illustrate the performance of the proposed TDC circuit.

Seismic Response Analysis of Reinforced Concrete Wall Structure Using Macro Model

  • Kim, Dong-Kwan
    • International Journal of Concrete Structures and Materials
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    • 제10권1호
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    • pp.99-112
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    • 2016
  • During earthquake, reinforced concrete walls show complicated post-yield behavior varying with shear span-to-depth ratio, re-bar detail, and loading condition. In the present study, a macro-model for the nonlinear analysis of multi-story wall structures was developed. To conveniently describe the coupled flexure-compression and shear responses, a reinforced concrete wall was idealized with longitudinal and diagonal uniaxial elements. Simplified cyclic material models were used to describe the cyclic behavior of concrete and re-bars. For verification, the proposed method was applied to various existing test specimens of isolated and coupled walls. The results showed that the predictions agreed well with the test results including the load-carrying capacity, deformation capacity, and failure mode. Further the proposed model was applied to an existing wall structure tested on a shaking table. Three-dimensional nonlinear time history analyses using the proposed model were performed for the test specimen. The time history responses of the proposed method agreed with the test results including the lateral displacements and base shear.

시멘트모르터 충진형 포장궤도의 실물 반복재하특성에 관한 연구 (Study on the Full-Scale Cyclic Loading Characteristics for Cement Mortar Pouring type Paved Track)

  • 이일화;장승엽;김은
    • 한국철도학회논문집
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    • 제9권3호
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    • pp.305-312
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    • 2006
  • Gravel ballasted tracks are used as a basic structure for the domestic railway tracks. However, such kind of tracks has few disadvantages with service life of the structure, such as rapid deterioration of the tracks. Due to this reason, there is a need to develop low maintenance track to improve the service life of the conventional line tracks. CMP paved tacks are one of the kind of concrete tracks those were manufactured by using the prepacked concrete techniques. The purpose to develop paved tracks is to reduce the maintenance cost. The most important controlling factors to design the paved tracks are surrounding environmental condition and repeated train loading. In this study, in order to investigate the deformation characteristics such as displacement, earth pressure, strain ratio, and crack along the repeated loading cycle, cyclic loading test through real scale model was carried out.

SKEW CYCLIC CODES OVER 𝔽p + v𝔽p + v2𝔽p

  • Mousavi, Hamed;Moussavi, Ahmad;Rahimi, Saeed
    • 대한수학회보
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    • 제55권6호
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    • pp.1627-1638
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    • 2018
  • In this paper, we study an special type of cyclic codes called skew cyclic codes over the ring ${\mathbb{F}}_p+v{\mathbb{F}}_p+v^2{\mathbb{F}}_p$, where p is a prime number. This set of codes are the result of module (or ring) structure of the skew polynomial ring (${\mathbb{F}}_p+v{\mathbb{F}}_p+v^2{\mathbb{F}}_p$)[$x;{\theta}$] where $v^3=1$ and ${\theta}$ is an ${\mathbb{F}}_p$-automorphism such that ${\theta}(v)=v^2$. We show that when n is even, these codes are either principal or generated by two elements. The generator and parity check matrix are proposed. Some examples of linear codes with optimum Hamming distance are also provided.