Excitons--bound pairs of electrons and holes created by light--are key to the optoelectronic behavior of carbon nanotubes (CNTs). However, because excitons are confined to extremely small regions and exist for only fleeting moments, it has been extremely challenging to directly observe their behavior using conventional measurement techniques.

In this study, we overcame that challenge by using an ultrafast infrared near-field optical microscope that focuses femtosecond infrared laser pulses down to the nanoscale. This advanced approach allowed us to visualize where excitons are generated and decay inside CNTs in real space and real time.

Our observations revealed that nanoscale variations in the local environment--such as subtle lattice distortions within individual CNTs or interactions with neighboring CNTs--can significantly affect exciton generation and relaxation dynamics.

These insights into local exciton dynamics pave the way for precise control of light-matter interactions at the nanoscale, offering new opportunities for the development of advanced optoelectronic devices and quantum technologies based on carbon nanotube platforms.

SAN ANTONIO — June 18, 2025 — Southwest Research Institute collaborated with Yale University to summarize the scientific community’s notable progress advancing the understanding of the formation and evolution of the inner rocky planets, the so-called terrestrial planets. Their Nature Review journal paper focuses on late accretion’s role in the long-term evolution of terrestrial planets, including their distinct geophysical and chemical properties as well as their potential habitability.

A research team at Beihang University, led by Professor Jianghao Wu, has achieved a significant breakthrough in the design of propulsion systems for future low-altitude transport, particularly electric Vertical Take-Off and Landing (eVTOL) aircraft. Their pioneering work, recently published in the Chinese Journal of Aeronautics, introduces a novel analytical framework for ducted propellers, promising to make these advanced flying vehicles smaller, lighter, and more powerful. This research offers vital support for the burgeoning field of advanced air mobility, aiming to alleviate urban traffic congestion and utilize low-altitude airspace.

In the history of aircraft development, maneuverability has always been an important consideration in the design concept of aircraft. The requirements for aerodynamic characteristics are reflected in high lift-to-drag ratio, high lift coefficient, torque stability and so on. The occurrence of dynamic stall will lead to a sharp drop in lift and a rapid rise in drag, resulting in torque oscillation, which seriously restricts the improvement of aircraft performance, and even leads to aircraft crash in severe cases. The traditional passive flow control cannot cope with the real-time and changeable flow field environment, and the emergence of jet control provides a new way to solve the problem of dynamic stall. Although the research of single jet technology has been relatively sufficient, there are few comparative studies on steady jet and synthetic jet, and there is also a lack of related research on dual synthetic jets. Therefore, it is imperative to fill this research gap.

Operating drones across air and water boundaries poses serious aerodynamic risks due to complex gas-liquid flow interactions. A new finite vortex rotor model developed by researchers in China provides unprecedented insight into how rotors behave near free water surface. The study introduces a predictive boundary that separates safe and unsafe flight zones, offering a powerful tool for the design and control of aerial-aquatic rotorcraft.

A research team from York University in Canada has proposed a revolutionary Dyson-Harrop CubeSat design, capable of harvesting high-density energy from the solar wind using the photoelectric effect. This compact and lightweight system delivers much greater power density than conventional photovoltaic technologies, opening up new possibilities for clean and sustainable space energy applications.

To reduce the vibration of the coaxial helicopter main transmission system considering both level and vertical flight conditions, a vibration evaluation and optimization model was built. A vibration simulation model and a vibration evaluation method was established. A hybrid Gravitational Search Algorithm-Simulated Annealing (GSA-SA) algorithm was combined to balance convergence speed and searching accuracy. The principle test was conducted to prove the accuracy of theoretical method. The optional results show that the vibration of the optimized transmission system decreases significantly, in which the maximum reduction of key vibration indicators reaches more than 20%. The proposed method could be extended to other fields.