A5062746241- Fluid Dynamics and Turbulent Flows
- Fluid Dynamics and Vibration Analysis
- Solar and Space Plasma Dynamics
- Lattice Boltzmann Simulation Studies
- Organic Electronics and Photovoltaics
- Phase Equilibria and Thermodynamics
- Conducting polymers and applications
- Silicon and Solar Cell Technologies
- Nanowire Synthesis and Applications
- Semiconductor materials and interfaces
- Tropical and Extratropical Cyclones Research
- Oceanographic and Atmospheric Processes
- Plant Water Relations and Carbon Dynamics
- Advanced Sensor and Energy Harvesting Materials
- Geological formations and processes
- Quantum, superfluid, helium dynamics
Peking University
2022-2024
State Key Laboratory of Turbulence and Complex Systems
2024
Conjugated polymers have demonstrated promising optoelectronic properties, but their brittleness and poor mechanical characteristics hindered fabrication into durable fibers textiles. Here, we report a universal approach to continuously producing highly strong, ultratough conjugated polymer using flow-enhanced crystallization (FLEX) method. These exhibit one order of magnitude higher tensile strength (>200 megapascals) toughness (>80 megajoules per cubic meter) than traditional...
Efficient and stable organic-silicon heterojunction solar cells are highly desirable. In this work, solution-processed poly(3,4-ethylenedioxythiophene): perfluorinated sulfonic acid (PEDOT:F) is investigated as hole-selective contact for crystalline silicon (c-Si) cells....
We propose the helicity-conserved Navier–Stokes (HCNS) equation by modifying non-ideal force term in (NS) equation. The corresponding HCNS flow has strict helicity conservation, and retains major NS dynamics with finite dissipation. Using helical wave decomposition, we show that pentadic interaction of Fourier modes is more complex than triadic dynamics, enhanced variations for left- right-handed components cancel each other to keep invariant helicity. A comparative study evolutions direct...
Helicity, an invariant under ideal-fluid (Euler) evolution, has a topological interpretation in terms of writhe and twist for closed vortex tube, but accurately quantifying is challenging viscous flows. With novel helicity decomposition, we present framework to construct the differential that establishes theoretical relation between total twisting number local rate each surface. This can characterize coiling lines internal structures within – important laminar–turbulence transition,...
Topological transition and helicity conversion of vortex torus knots links are studied using direct numerical simulations the incompressible Navier–Stokes equations. We find three topological transitional routes ( viz. merging, reconnection to turbulence) in evolution over a range aspect ratios winding numbers. The depends not only on initial topology but also geometry knots/links. For small ratios, initially knotted or linked tube rapidly merges into ring with complete from writhe link...
The dynamics of two slender Hopf-linked vortex rings at Reynolds numbers ( $Re \equiv \varGamma /\nu, \mathrm {circulation/viscosity}$ ) $2000$ , $3000$ and $4000$ is studied using direct numerical simulations the incompressible Navier–Stokes equations. Under self-induction, initially perpendicularly placed approach each other reconnect to form separate rings. leading ring closely cuddled further undergoes secondary reconnection even smaller At high $Re$ subsequent are unstable break up into...
Matter entanglement is a common chaotic structure found in both quantum and classical systems. For turbulence, viscous vortices are like sinews fluid flows, storing dissipating energy accommodating strain stress throughout complex vortex network. However, to explain how the statistical properties of turbulence arise from elemental vortical structures remains challenging. Here, we use tangle as skeleton generate an instantaneous turbulent field with intertwined tubes. Combining tunable...
Matter entanglement is a common chaotic structure in both quantum and classical systems. Turbulence can be pictured as tangle of vortex filaments superfluids viscous vortices fluids. However, it hard to explain how the statistical properties turbulence arise from elemental structures. Here we use skeleton generate an instantaneous turbulent field with intertwined tubes. Combining tunable thickness makes synthetic satisfy key laws provides valuable insights for elucidating energy cascade...