The Experts below are selected from a list of 111708 Experts worldwide ranked by ideXlab platform
Alan Aspuruguzik - One of the best experts on this subject based on the ideXlab platform.
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efficiency of energy funneling in the photosystem ii supercomplex of higher plants
Chemical Science, 2016Co-Authors: Christoph Kreisbeck, Alan AspuruguzikAbstract:The investigation of energy transfer properties in photosynthetic multi-protein networks gives insight into their underlying design principles. Here, we discuss the excitonic energy transfer mechanisms of the photosystem II (PS-II) C2S2M2 supercomplex, which is the largest isolated functional unit of the photosynthetic apparatus of higher plants. Despite the lack of a definite energy gradient in C2S2M2, we show that the energy transfer is directed by relaxation to low energy states. C2S2M2 is not organized to form pathways with strict energetically downhill transfer, which has direct consequences for the transfer efficiency, transfer pathways and transfer limiting steps. The exciton dynamics is sensitive to small changes in the energetic layout which, for instance, are induced by the reorganization of vibrational coordinates. In order to incorporate the reorganization process in our numerical simulations, we go beyond rate Equations and use the hierarchically Coupled Equation of motion approach (HEOM). While transfer from the peripheral antenna to the proteins in proximity to the reaction center occurs on a faster time scale, the final step of the energy transfer to the RC core is rather slow, and thus the limiting step in the transfer chain. Our findings suggest that the structure of the PS-II supercomplex guarantees photoprotection rather than optimized efficiency.
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efficiency of energy funneling in the photosystem ii supercomplex of higher plants
arXiv: Biological Physics, 2015Co-Authors: Christoph Kreisbeck, Alan AspuruguzikAbstract:The investigation of energy transfer properties in photosynthetic multi-protein networks gives insight into their underlying design principles.Here, we discuss excitonic energy transfer mechanisms of the photosystem II (PS-II) C$_2$S$_2$M$_2$ supercomplex, which is the largest isolated functional unit of the photosynthetic apparatus of higher plants.Despite the lack of a decisive energy gradient in C$_2$S$_2$M$_2$, we show that the energy transfer is directed by relaxation to low energy states. C$_2$S$_2$M$_2$ is not organized to form pathways with strict energetic downhill transfer, which has direct consequences on the transfer efficiency, transfer pathways and transfer limiting steps. The exciton dynamics is sensitive to small structural changes, which, for instance, are induced by the reorganization of vibrational coordinates. In order to incorporate the reorganization process in our numerical simulations, we go beyond rate Equations and use the hierarchically Coupled Equation of motion approach (HEOM). While transfer from the peripherical antenna to the proteins in proximity to the reaction center occurs on a faster time scale, the final step of the energy transfer to the RC core is rather slow, and thus the limiting step in the transfer chain. Our findings suggest that the structure of the PS-II supercomplex guarantees photoprotection rather than optimized efficiency.
Christoph Kreisbeck - One of the best experts on this subject based on the ideXlab platform.
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efficiency of energy funneling in the photosystem ii supercomplex of higher plants
Chemical Science, 2016Co-Authors: Christoph Kreisbeck, Alan AspuruguzikAbstract:The investigation of energy transfer properties in photosynthetic multi-protein networks gives insight into their underlying design principles. Here, we discuss the excitonic energy transfer mechanisms of the photosystem II (PS-II) C2S2M2 supercomplex, which is the largest isolated functional unit of the photosynthetic apparatus of higher plants. Despite the lack of a definite energy gradient in C2S2M2, we show that the energy transfer is directed by relaxation to low energy states. C2S2M2 is not organized to form pathways with strict energetically downhill transfer, which has direct consequences for the transfer efficiency, transfer pathways and transfer limiting steps. The exciton dynamics is sensitive to small changes in the energetic layout which, for instance, are induced by the reorganization of vibrational coordinates. In order to incorporate the reorganization process in our numerical simulations, we go beyond rate Equations and use the hierarchically Coupled Equation of motion approach (HEOM). While transfer from the peripheral antenna to the proteins in proximity to the reaction center occurs on a faster time scale, the final step of the energy transfer to the RC core is rather slow, and thus the limiting step in the transfer chain. Our findings suggest that the structure of the PS-II supercomplex guarantees photoprotection rather than optimized efficiency.
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efficiency of energy funneling in the photosystem ii supercomplex of higher plants
arXiv: Biological Physics, 2015Co-Authors: Christoph Kreisbeck, Alan AspuruguzikAbstract:The investigation of energy transfer properties in photosynthetic multi-protein networks gives insight into their underlying design principles.Here, we discuss excitonic energy transfer mechanisms of the photosystem II (PS-II) C$_2$S$_2$M$_2$ supercomplex, which is the largest isolated functional unit of the photosynthetic apparatus of higher plants.Despite the lack of a decisive energy gradient in C$_2$S$_2$M$_2$, we show that the energy transfer is directed by relaxation to low energy states. C$_2$S$_2$M$_2$ is not organized to form pathways with strict energetic downhill transfer, which has direct consequences on the transfer efficiency, transfer pathways and transfer limiting steps. The exciton dynamics is sensitive to small structural changes, which, for instance, are induced by the reorganization of vibrational coordinates. In order to incorporate the reorganization process in our numerical simulations, we go beyond rate Equations and use the hierarchically Coupled Equation of motion approach (HEOM). While transfer from the peripherical antenna to the proteins in proximity to the reaction center occurs on a faster time scale, the final step of the energy transfer to the RC core is rather slow, and thus the limiting step in the transfer chain. Our findings suggest that the structure of the PS-II supercomplex guarantees photoprotection rather than optimized efficiency.
Yonghwan Kim - One of the best experts on this subject based on the ideXlab platform.
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Time domain springing analysis on a floating barge under oblique wave
Journal of Marine Science and Technology, 2009Co-Authors: Yooil Kim, Kyong-hwan Kim, Yonghwan KimAbstract:This paper studies the springing response of a flexible floating barge under an oblique wave. A time domain Rankine panel method was used to represent fluid motion surrounding a flexible seagoing vessel, and a finite element method was used for structural response. For accurate prediction of the structural response under an oblique wave, special attention was given to the structural model, such as the effect of warping distortion and bending-torsion coupling. The Vlasov assumption was followed for a deformable beam element to take into account the effect of warping distortion so that the cross section of the beam deforms out of its original plane without changing its cross-section contour. The Coupled Equation for both the fluid and structural domain was solved by using the implicit iterative method. A fixed point iteration with a relaxation scheme was employed in this study with the aid of the Aitken δ^2 process seeking acceleration of solution convergence. Accuracy of a developed computer program was verified through the comparison with experimental work done by Remy et al. (Experimental and numerical study of the wave response of a flexible barge, Hydroelasticity in Marine Technology , Wuxi, 2006) resulting in good correspondence between the two results.
Shinobu Yoshimura - One of the best experts on this subject based on the ideXlab platform.
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A monolithic approach for interaction of incompressible viscous fluid and an elastic body based on fluid pressure Poisson Equation
International Journal for Numerical Methods in Engineering, 2005Co-Authors: Daisuke Ishihara, Shinobu YoshimuraAbstract:This paper describes a new monolithic approach based on the fluid pressure Poisson Equation (PPE) to solve an interaction problem of incompressible viscous fluid and an elastic body. The PPE is derived so as to be consistent with the Coupled Equation system for the fluid-structure interaction (FSI). Based on this approach, we develop two kinds of efficient monolithic methods. In both methods, the fluid pressure is derived implicitly so as to satisfy the incompressibility constraint, and all other unknown variables are derived fully explicitly or partially explicitly. The coefficient matrix of the PPE for the FSI becomes symmetric and positive definite and its condition is insensitive to inhomogeneity of material properties. The arbitrary Lagrangian–Eulerian (ALE) method is employed for the fluid part in order to take into account the deformable fluid-structure interface. To demonstrate fundamental performances of the proposed approach, the developed two monolithic methods are applied to evaluate the added mass and the added damping of a circular cylinder as well as to simulate the vibration of a rectangular cylinder induced by vortex shedding. Copyright © 2005 John Wiley & Sons, Ltd.
Chenheng Yuan - One of the best experts on this subject based on the ideXlab platform.
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Bifurcation and chaos analysis of torsional vibration in a PMSM-based driven system considering electromechanically Coupled effect
Nonlinear Dynamics, 2017Co-Authors: Xing Chen, Jibin Hu, Zengxiong Peng, Chenheng YuanAbstract:The rotor of PMSM-based electromechanically driven system is a typical electromechanically Coupled system. In this paper, we analyzed the nonlinear magnetic interaction torque of permanent magnet synchronous motor (PMSM) and deduced the nonlinear electromechanically Coupled Equation of PMSM-based electromechanical driven system using Lagrange–Maxwell theory. We determined the Equation of the movement of the dynamic system from his asymmetric double well potential. The unperturbed system was classified to several categories based on the shapes of potential functions and phase portraits. An analytical criterion for homoclinic chaos is written in terms of the system parameters by means of Melnikov’s method. Detailed numerical studies including phase portrait, Poincare map, and bifurcation diagram confirm the analytical prediction and reveal the effect of excitation amplitude and damp on the system transition to chaos. The conclusion can provide reference for deeply research the dynamic behaviors of mechanical drive system.
