TechTalk

November 5, 2026 (Thursday) 11:00am-12:00nn
Rock failure is not simply a continuous medium failure, but a cross-scale catastrophic process emerging from mesoscopic heterogeneity. Based on the Rock Failure Process Analysis (RFPA) method, this report elaborates on three levels of failure catastrophe: at the mesoscopic scale, statistical heterogeneity of material strength governs damage initiation and localization; at the macroscopic scale, damage accumulation and stress redistribution drive crack coalescence, structural instability, and catastrophe; at the mega-scale, this principle is extended to the planetary lithosphere, forming the “Breakup of Earth” theory—thermal accumulation drives global self-organized fracturing, triggering decompression melting and global net cooling. The three scales follow a unified physical logic: heterogeneity → damage evolution → self-organized criticality → catastrophe. The report will discuss the implications of this cross-scale framework for understanding earthquakes, rockbursts, and the origin of plate tectonics.

November 3, 2026 (Tuesday) 10:00am-11:00am
Recognising the fundamental importance of Newton’s law of cooling in convective heat transfer, people may still ask: was/is it accurate enough? The answer might vary depending on what applications and when it was/is applied to. It is noted that Newton’s 1701 paper attributed to the Law was published anonymously, (unlike his other major scientific publications). It is also known that Sir Issac Newton apparently had never used the term ‘Heat Transfer Coefficient (HTC)’, arguably the most researched and used parameter in the whole field of convective heat transfer! What do these mean in terms of the applicability/uncertainty of the law as we know it, particularly when applied to modern advanced thermal management in 2020s?
The primary issue of interest is the applicability of the cooling law for a non-isothermal wall (with non- uniform surface temperatures). A general Green’s function-based framework exists but there has been no working computational method for implementation. A first-principle analysis indicates that the law of cooling and the directly solved Green’s function are both restricted by a structural modelling limitation: a range of physically relevant and numerically resolvable length scales are missing as a consequence.
The present development effort takes a different pathway. Instead of resolving the local-local influence and response, a new Spectral Heat Transfer Coefficients (SHTC) method sets up and solves global-to-local temperature-heat flux influences for a small number of spectral modes of wall temperature disturbances in a range of physically relevant and numerically resolvable length scales.
Two aerothermal regimes (linear & nonlinear) are considered respectively. First the SHTC approach is described and applied for an incompressible flow where the energy equation is decoupled from the rest eqs, and behaves linearly. Then, the corresponding temperature field is passively dictated by the velocity field. Secondly, the methodology is extended to a nonlinear regime, where the temperature field actively interact with (rather than passively influenced by) the velocity field (as in a compressible flow).
Given the time contraint, the talk serves to provide an overview/highlight of the main findings of the following recent publications on the topic:
– He, L. (2023) “Spectral Heat Transfer Coefficient for Convection”, International Journal of Heat and Mass Transfer, Vol.216, 124557 (https://doi.org/10.1016/j.ijheatmasstransfer.2023.124557).
– He L. (2023) “Chapter 2 – Conjugate Heat Transfer: Some Fundamentals and Recent Progress”, Advances in Heat Transfer, Elsevier (https://doi.org/10.1016/bs.aiht.2023.02.002).
– He, L. (2025) “Spectral Heat Transfer Coefficient for Thermal Design Analysis – PartI: Augmenting the Cooling Law for Non-Isothermal Wall”, ASMEJ. of TURBO. 147(6), (https://doi.org/10.1115/1.4066671). (the 2024 ASME Turbo Expo Congress Heat Transfer Best Paper Award).
– He, L. (2025) “Spectral Heat Transfer Coefficient for Thermal Design Analysis – Part II: Leveraging Diabatic Wall Conditioning for Nonlinear Regime”, ASMEJ. TURBO. 147(6), (https://doi.org/10.1115/1.4066672).

October 15, 2026 (Thursday) 4pm-5pm
Traditionally central to energy conversion, combustion is now being reimagined as a powerful tool for manufacturing and recycling materials critical to energy storage and sustainability. Flame-based spray methods, for example, offer a continuous, rapid, and scalable route to synthesizing and rejuvenating lithium-ion battery (LIB) cathode materials. These processes can reduce production costs, enable efficient material recycling, and improve performance. I will highlight flame-assisted spray pyrolysis as a technique for controlling particle morphology and tailoring electrochemical properties, all within synthesis times orders of magnitude shorter than conventional routes. Yet, alongside these manufacturing advances come critical safety challenges, most notably thermal runaway, a failure mode that can trigger hazardous battery fires. To address these concerns, I will introduce our newly developed Chemical Reaction Neural Network, a data-driven framework that uncovers reaction pathways and infers kinetic parameters directly from data, without requiring prior mechanistic knowledge. This approach offers a new window into the chemistry behind thermal runaway and other reactive phenomena, helping us better understand both the flames that create and the flames that destroy.

August 10, 2026 (Thursday) 10:30am-11:30am
Over the last 28 years, our laboratory has focused on the designed chemical synthesis and assembly of uniform-sized nanocrystals and related nanomaterials, and their biomedical, energy and soft-electronic-device applications. Especially, we invented the “heat-up process”, a simple and reproducible method to produce large quantity of uniform-sized nanoparticles (Nano Lett. 2026, 26, 4525; JACS 2001, 123, 12798; Nat. Mater. 2004, 3, 891). We fabricated ultra-flexible and/or stretchable soft-electronic quantum-dot light-emitting diodes (QLEDs). We reported a novel device design and fabrication method for 3D foldable quantum dot light-emitting diodes (QLEDs) (Nat. Elec. 2021, 4, 671), and intrinsically-stretchable QLEDs (is-QLED) (Nat. Elec. 2024, 7, 365).
For the last decade, our group has also developed several synthetic methods to produce single-atom catalysts and nanocatalysts for photo-& electro-catalytic hydrogen production and utilization such as H2O2 electrosynthesis (Nat. Mater. 2024, 23, 552, Nat. Nano. 2023, 18, 754, Nat. Nano. 2025, 20, 1237).

May 15, 2026 (Thursday) 11:30am-12:00nn
Photovoltaic (PV) panels are typically less than 20% efficient in delivering electricity from the Sun’s
energy. The efficiency losses are especially pronounced when PV panels are exposed to high
irradiance conditions on warm, sunny days, which lead to higher temperature operation. Of the
total amount of sunlight incident on PV panels, over 70% is lost to the environment as waste heat.
This loss has motivated the development of ‘hybrid’ PV-thermal (PV-T) collectors, which combine
PV cells with a contacting fluid. The fluid recovers waste heat from the cells, thus delivering a
potentially useful thermal output, while simultaneously cooling the cells and increasing their
electrical efficiency. Recently, a new concept that we refer to as multifunctional ‘PV-X’ collector
technology has emerged, in which secondary processes are integrated synergistically with the PV
cells, exploiting the available waste heat to perform additional functions directly within the collector.
In this talk, we will present conventional and advanced PV-T and PV-X collector concepts and
designs, along with their underlying operational principles. We will explore opportunities for further
developing these technologies and examine how new materials can drive improvements from the
component to the system level, while discussing the potential of integrating these technologies into
broader solar-energy systems capable of providing cooling, heating, power, fuels or clean water.

May 5, 2026 (Tuesday) 10:30am-11:30am
In this talk, I’ll walk you through my research on medical and industrial exoskeletons at the University of California, Berkeley, as well as the development work at the two companies I founded in the United States. I’ll then focus on two main points.
First, the darker side of the overwhelming push across U.S. universities to encourage entrepreneurial work.
Second—and despite the first point—my next venture: how it took shape in my mind, influenced by the geographic and political landscape of West–East economic rivalries.
My goal is to create genuine motivation for some of you to join me, either as a co-founder or collaborator, to help bring this new venture to maturity.