February 2024

TechTalk – The World at the Microscale: From Swimming Microorganisms to Artificial Microrobots

March 14 2024 (Thursday) 4:30-5:30pm
Swimming at microscales encounters stringent physical constraints due to the dominance of viscous forces over inertial forces. Swimming microorganisms have evolved their flexible appendages to overcome these constraints to swim effectively. These natural swimmers also developed versatile navigation strategies to explore their surroundings and search for specific targets. Extensive efforts in the past few decades have sought to elucidate underlying physical principles for cell motility, which has inspired a variety of designs for artificial microrobots. In this talk, I will discuss two problems of microswimmers in biological and artificial systems. I will first discuss the biophysical mechanisms through which swimming microorganisms sense and navigate their surroundings. I will then discuss the application of artificial intelligence in the development of intelligent microrobots that can self-learn how to swim and navigate at the microscale.

Young Scholar TechTalk – Customizable Acoustic Metamaterials on Frequency and Spatial Dimensions

March 12 2024 (Tuesday) 4:30-5:30pm
Acoustic metamaterials are artificially designed structured ‘atoms’. Initially, scientists discovered that these meta-atoms can exhibit extraordinary properties beyond those found in natural materials, such as negative density and negative modulus, through localized resonance, which sparked significant interest in the academic community. Subsequently, it was confirmed that these unique narrow-band frequency responses can be extended to broadband impedance designs, leading directly to the emergence of absorption metamaterials and opening up large-scale applications in noise reduction. In recent years, the potential of customizable metamaterials has gradually been realized. We will present our latest works from two complementary perspectives: customized frequencies and spatial non-uniformity, which may open up new applications such as directional emission, stealth cloaking and automotive acoustics.

TechTalk – Device-Independent Quantum Key Generation

March 7 2024 (Thursday) 4:30-5:30pm
The extraction of private, uniformly random bits from weakly random seeds is a problem of central importance in cryptography with multiple applications. A well-known result in classical computer science states that randomness extraction is possible using classical resources only when multiple independent sources are available. On the other hand, Quantum Entanglement enables a solution to the problem even in the so-called device-independent framework. Device-Independent quantum cryptography offers the highest form of security, wherein the users do not need to even trust the devices executing the cryptographic protocol, and can instead verify correctness and security by means of simple statistical tests on the devices. In this talk, we report on the state-of-art theoretical and experimental results on device-independent quantum cryptography, with a focus on quantum randomness amplification and quantum key distribution.

Hybrid Assembly of Polymeric Nanofiber Network for Robust and Electronically Conductive Hydrogels

Hydrogels are promising candidate materials for the construction of soft electronics and biomedical devices due to their mechanical flexibility, structural permeability, and biocompatibility. However, achieving high electrical conductivity and mechanical robustness in hydrogels remains challenging, which limits their practical applications.
Professor Lizhi Xu’s research team has developed a new type of electroconductive hydrogels with outstanding mechanical strength and manufacturability.

TechTalk – Nature-Inspired Fluidics

February 29 2024 (Thursday) 4:30-5:30pm
Fluids are ubiquitous in nature and transport of fluids plays an essential role in sustaining many activities across multiple scales. The mode of fluidic transport therefore also spans multiple length scales. Moreover, despite largely aqueous in nature, natural fluids exhibit complexity, dynamics and structures that have yet to be replicated synthetically. In this talk, I will share our works in designing approaches to form, manipulate and direct aqueous solutions. In particular, I will focus on unique properties of aqueous multiphase systems that may serve as model systems for understanding their natural counterparts. I will conclude by discussing how these systems can potentially inspire biomimetic and biomedical applications.