scholarly journals Probing atom dynamics of excited Co-Mo-S nanocrystals in 3D

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Fu-Rong Chen ◽  
Dirk Van Dyck ◽  
Christian Kisielowski ◽  
Lars P. Hansen ◽  
Bastian Barton ◽  
...  
Keyword(s):  
Analytical Approach ◽  
Three Dimensional ◽  
Phase Image ◽  
Chemical Transformations ◽  
Time Resolved ◽  
Single Atoms ◽  
Heterogeneous Chemical ◽  
Structures And Properties ◽  
Resolution Imaging ◽  
Atom Dynamics

AbstractAdvances in electron microscopy have enabled visualizations of the three-dimensional (3D) atom arrangements in nano-scale objects. The observations are, however, prone to electron-beam-induced object alterations, so tracking of single atoms in space and time becomes key to unravel inherent structures and properties. Here, we introduce an analytical approach to quantitatively account for atom dynamics in 3D atomic-resolution imaging. The approach is showcased for a Co-Mo-S nanocrystal by analysis of time-resolved in-line holograms achieving ~1.5 Å resolution in 3D. The analysis reveals a decay of phase image contrast towards the nanocrystal edges and meta-stable edge motifs with crystallographic dependence. These findings are explained by beam-stimulated vibrations that exceed Debye-Waller factors and cause chemical transformations at catalytically relevant edges. This ability to simultaneously probe atom vibrations and displacements enables a recovery of the pristine Co-Mo-S structure and establishes, in turn, a foundation to understand heterogeneous chemical functionality of nanostructures, surfaces and molecules.

scholarly journals Picosecond time-resolved photon antibunching measures nanoscale exciton motion and the true number of chromophores

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gordon J. Hedley ◽  
Tim Schröder ◽  
Florian Steiner ◽  
Theresa Eder ◽  
Felix J. Hofmann ◽  
...  
Keyword(s):  
Rational Design ◽  
Three Dimensional ◽  
Dna Origami ◽  
Fluorescent Nanoparticles ◽  
Time Resolved ◽  
Exciton Diffusion ◽  
Polymer Aggregates ◽  
True Number ◽  
Particle Level ◽  
Photon Antibunching

AbstractThe particle-like nature of light becomes evident in the photon statistics of fluorescence from single quantum systems as photon antibunching. In multichromophoric systems, exciton diffusion and subsequent annihilation occurs. These processes also yield photon antibunching but cannot be interpreted reliably. Here we develop picosecond time-resolved antibunching to identify and decode such processes. We use this method to measure the true number of chromophores on well-defined multichromophoric DNA-origami structures, and precisely determine the distance-dependent rates of annihilation between excitons. Further, this allows us to measure exciton diffusion in mesoscopic H- and J-type conjugated-polymer aggregates. We distinguish between one-dimensional intra-chain and three-dimensional inter-chain exciton diffusion at different times after excitation and determine the disorder-dependent diffusion lengths. Our method provides a powerful lens through which excitons can be studied at the single-particle level, enabling the rational design of improved excitonic probes such as ultra-bright fluorescent nanoparticles and materials for optoelectronic devices.

scholarly journals Three-dimensional super-resolution imaging for fluorescence emission difference microscopy

AIP Advances ◽  
2015 ◽  
Vol 5 (8) ◽  
pp. 084901 ◽  
Author(s):  
Shangting You ◽  
Cuifang Kuang ◽  
Shuai Li ◽  
Xu Liu ◽  
Zhihua Ding
Keyword(s):  
Three Dimensional ◽  
Fluorescence Emission ◽  
Super Resolution ◽  
Resolution Imaging

Super-resolution imaging using a three-dimensional metamaterials nanolens

2010 ◽  
Vol 96 (2) ◽  
pp. 023114 ◽  
Author(s):  
B. D. F. Casse ◽  
W. T. Lu ◽  
Y. J. Huang ◽  
E. Gultepe ◽  
L. Menon ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Super Resolution ◽  
Resolution Imaging

Three-dimensional lanthanide–silver heterometallic coordination polymers: syntheses, structures and properties

CrystEngComm ◽  
2010 ◽  
Vol 12 (10) ◽  
pp. 3267 ◽  
Author(s):  
Man-Sheng Chen ◽  
Zhi Su ◽  
Min Chen ◽  
Shui-Sheng Chen ◽  
Yi-Zhi Li ◽  
...  
Keyword(s):  
Coordination Polymers ◽  
Three Dimensional ◽  
Structures And Properties ◽  
Heterometallic Coordination Polymers

Impact of an Aortic Nitinol Stent Graft on Flow Measurements by Time-resolved Three-dimensional Velocity-encoded MRI

2012 ◽  
Vol 19 (3) ◽  
pp. 274-280 ◽  
Author(s):  
Fabian Rengier ◽  
Michael Delles ◽  
Roland Unterhinninghofen ◽  
Sebastian Ley ◽  
Sasan Partovi ◽  
...  
Keyword(s):  
Stent Graft ◽  
Three Dimensional ◽  
Flow Measurements ◽  
Time Resolved ◽  
Nitinol Stent

The Influence of Static Response of Super Tall Building Mega-Frame Structure Caused by Changes of Frame Rigidities

2012 ◽  
Vol 166-169 ◽  
pp. 277-281
Author(s):  
Xiang Dong Xie ◽  
Xuan Wang ◽  
Li Qin
Keyword(s):  
Differential Equation ◽  
Analytical Approach ◽  
Three Dimensional ◽  
Tall Building ◽  
Frame Structure ◽  
Thin Wall ◽  
Static Response ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Frame Rigidity

The superstructure and its foundation of a super tall building mega-frame structure are simplified equivalently and continuously to a stiffened-thin-wall tube on semi-infinite elastic subgrade. And the influences of static response on super tall building mega-frame structure caused by changes of frame rigidity are computed and analyzed with the three-dimensional model by semi-analytical approach based on ODE(Ordinary Differential Equation) Solver, considering the interactions of subgrade, foundation and superstructure. Then some valuable conclusions are obtained through analyzing the reasonable results of the numerical example.

Effects of Downstream Vane Bowing and Asymmetry on Unsteadiness in a Transonic Turbine

2018 ◽  
Author(s):  
John P. Clark ◽  
Richard J. Anthony ◽  
Michael K. Ooten ◽  
John M. Finnegan ◽  
P. Dean Johnson ◽  
...  
Keyword(s):  
Turbine Blades ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Time Resolved ◽  
Turbine Engine ◽  
Shock Interactions ◽  
Design Changes ◽  
Post Test ◽  
Measured Time ◽  
Transonic Turbine

Accurate predictions of unsteady forcing on turbine blades are essential for the avoidance of high-cycle-fatigue issues during turbine engine development. Further, if one can demonstrate that predictions of unsteady interaction in a turbine are accurate, then it becomes possible to anticipate resonant-stress problems and mitigate them through aerodynamic design changes during the development cycle. A successful reduction in unsteady forcing for a transonic turbine with significant shock interactions due to downstream components is presented here. A pair of methods to reduce the unsteadiness was considered and rigorously analyzed using a three-dimensional, time resolved Reynolds-Averaged Navier Stokes (RANS) solver. The first method relied on the physics of shock reflections itself and involved altering the stacking of downstream components to achieve a bowed airfoil. The second method considered was circumferentially-asymmetric vane spacing which is well known to spread the unsteadiness due to vane-blade interaction over a range of frequencies. Both methods of forcing reduction were analyzed separately and predicted to reduce unsteady pressures on the blade as intended. Then, both design changes were implemented together in a transonic turbine experiment and successfully shown to manipulate the blade unsteadiness in keeping with the design-level predictions. This demonstration was accomplished through comparisons of measured time-resolved pressures on the turbine blade to others obtained in a baseline experiment that included neither asymmetric spacing nor bowing of the downstream vane. The measured data were further compared to rigorous post-test simulations of the complete turbine annulus including a bowed downstream vane of non-uniform pitch.

Blade-Row Interactions in an LP Turbine at Design and Strong Off-Design Operation

2014 ◽  
Author(s):  
Martin Lipfert ◽  
Jan Habermann ◽  
Martin G. Rose ◽  
Stephan Staudacher ◽  
Yavuz Guendogdu
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Three Dimensional ◽  
Suction Side ◽  
Test Facility ◽  
Time Resolved ◽  
Joint Project ◽  
Multi Stage ◽  
Blade Row ◽  
Wake Interactions

In a joint project between the Institute of Aircraft Propulsion Systems (ILA) and MTU Aero Engines a two-stage low pressure turbine is tested at design and strong off-design conditions. The experimental data taken in the altitude test-facility aims to study the effect of positive and negative incidence of the second stator vane. A detailed insight and understanding of the blade row interactions at these regimes is sought. Steady and time-resolved pressure measurements on the airfoil as well as inlet and outlet hot-film traverses at identical Reynolds number are performed for the midspan streamline. The results are compared with unsteady multi-stage CFD predictions. Simulations agree well with the experimental data and allow detailed insights in the time-resolved flow-field. Airfoil pressure field responses are found to increase with positve incidence whereas at negative incidence the magnitude remains unchanged. Different pressure to suction side phasing is observed for the studied regimes. The assessment of unsteady blade forces reveals that changes in unsteady lift are minor compared to changes in axial force components. These increase with increasing positive incidence. The wake-interactions are predominating the blade responses in all regimes. For the positive incidence conditions vane 1 passage vortex fluid is involved in the midspan passage interaction leading to a more distorted three-dimensional flow field.

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