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LZ
Verified CAS / Academic Author16 Decoded Studies

Prof. LIU Zhen

School of Civil Engineering, Shandong Jianzhu University, Jinan 250101, China; School of Civil Engineering, Tsinghua University, Beijing 100084, China

Co-Affiliations:State Key Laboratory of High Performance Ceramics, Shanghai Institute of Ceramics, Chinese Academy of SciencesCAS Key Laboratory for Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, ChinaImperial College London

Research Publications & English Decoded Briefs

Showing 16 publications
Surface Technology (表面技术)2026DOI: 10.16490/j.cnki.issn.1001-3660.2026.12.004

Test and Simulation Analysis on the Corrosion Evolution over Time of H-shaped Steel Components

H-shaped steel components are ubiquitous in steel structures, yet corrosion research has largely remained confined to two-dimensional flat plates, leaving the spatial-geometric effects on three-dimensional sections poorly quantified. This study addresses that gap through neutral salt spray (NSS) corrosion experiments on H-shaped steel specimens positioned at 0°, 45°, and 90° over corrosion cycles extending to 60 days, coupled with a three-dimensional cellular automata (3D-CA) model of the corrosion evolution. The spatial placement angle exerts a decisive influence on corrosion distribution. At 0° and 45°, the upper flange corrodes more severely than the web, while the lower flange remains least affected; the 45° specimen, however, exhibits accelerated attack because its inclined geometry prevents formation of a protective NaCl electrolyte film on the flanges. At 60 days, the 45° specimen's F1 surface shows average rust layer thickness and average pit depth exceeding those of the 0° specimen by 45.79% and 54.78%, respectively. At 90°, the W1 surface is most severely corroded, followed by the flanges, with W2 least affected. The 3D-CA model reproduces the time-dependent corrosion morphology, yielding pit depth distributions consistent with a Weibull function and agreeing with experimental pit morphology and depth within 5% error. The model is validated as a reliable predictor of spatially heterogeneous corrosion evolution in H-shaped steel, though it currently omits coupled stress and external loading effects.

Journal of Inorganic Materials (无机材料学报)2026DOI: 10.15541/jim20260018

Influence of Preparation Processes on the Structure and Properties of the Ductile Thermoelectric Material Ag2S0.4Te0.6

Ag2S0.4Te0.6 is an inorganic semiconductor with favorable ductility and thermoelectric performance, showing potential for applications in wearable electronics. Recent studies have indicated that optimization of preparation processes, such as annealing, can significantly enhance the ductility of the material, which is closely related to its phase composition and crystal structure. In this work, high-resolution synchrotron radiation powder X-ray diffraction data of the Ag2S0.4Te0.6 powder sample before and after annealing were collected over a temperature range of 110–700 K. By combining Rietveld structural refinement, high-resolution transmission electron microscopy, and atomic pair distribution function analysis, the influence of the annealing process on the phase composition and structural evolution behavior of the powder samples was investigated in detail. The results show that the pristine Ag2S0.4Te0.6 powder is predominantly amorphous, containing only a small amount of poorly crystalline monoclinic phase. During heating, the material gradually crystallizes, first forming a monoclinic phase, which subsequently transforms into mixed body-centered cubic (bcc) and face-centered cubic (fcc) phases. After cooling back to room temperature, the sample remains in a mixed state of bcc-dominated cubic crystallinity and amorphous phase. In contrast, the annealed powder sample already exhibits a mixed cubic crystalline/amorphous state at room temperature, and no obvious phase transition behavior is observed during heating. Moreover, the thermoelectric properties of Ag2S0.4Te0.6 bulk sample remain largely unaffected by the annealing process. This study provides structural insights for further understanding the annealing-induced improvement in ductility.

Journal of Semiconductors (半导体学报 - 中国科学院半导体研究所)2026DOI: 10.1088/1674-4926/25070024

Optimization and Defect Control in Photoresist Etch Back Processes for Advanced Semiconductor Technologies

The introduction of high-k/metal gate (HK/MG) technology enables independent tuning of NMOS and PMOS threshold voltages, facilitating advanced nodes and improving overall chip performance. However, severe pattern loading effects during PMOS device fabrication pose challenges in dummy poly removal. This work reports the optimization of the photoresist etch back (PREB) process, providing a wider process window for subsequent AL CMP. By tuning the PR coating uniformity to 1.6% and applying four-zone electrostatic chuck (ESC) temperature control, the wafer-level uniformities of PR, SiN, and SiO2 were reduced to 6.3%, 2.3%, and 5.1%, respectively. An optimized over etch (OE) recipe with a high selectivity of PR : SiN : SiO2 ≈ 1 : 1 : 6 effectively balanced gate height loading between N- and PMOS regions. Furthermore, precise EB1 time tuning enabled defect removal, while advanced KLA inspection ensured early detection of critical failure modes. Collectively, these measures establish a robust and stable PREB process for advanced logic device fabrication.

China Foundry2026DOI: 10.1007/s41230-026-5243-x

Factors influencing high-temperature compressive strength of alkaline phenolic resin-bonded sand

During the casting process, no-bake resin-bonded sand molds and cores rapidly heat up upon contact with high-temperature molten metal, causing dramatic changes in the resin binder system and a significant deterioration in mechanical properties, which subsequently leads to casting defects. To reveal the mechanism behind the evolution of high-temperature performance, the effects of resin content, base sand type, and particle size on the compressive strength of alkaline phenolic no-bake resin-bonded sand at temperatures ranging from 600 °C to 1,000 °C were investigated. The results show that the temperature range of 600-800 °C represents the primary stage of strength loss, corresponding to intense resin decomposition. Meanwhile, structural reorganization of the carbon skeleton above 900 °C can lead to a partial recovery of strength. This study provides key data and theoretical support for understanding the high-temperature mechanical behavior of resin-bonded sand and its relationship with casting defects.

Nano-Micro Letters2025DOI: 10.1007/s40820-025-01776-3

Efficient Thermally Evaporated Near-Infrared Perovskite Light-Emitting Diodes via Phase Regulation

α-phase formamidinium lead triiodide (FAPbI3) has demonstrated extraordinary properties for near-infrared perovskite light-emitting diodes (NIR-PeLEDs). The vacuum processing technique has recently received increasing attention from industry and academia due to its solvent-free feature and compatibility with large-scale production. Nevertheless, vacuum-deposited NIR-PeLEDs have been less studied, and their efficiencies lag far behind those of solution-based PeLEDs as it is still challenging to prepare pure α-FAPbI3 by the thermal evaporation. Herein, we report a Cs-containing triple-source co-evaporation approach to develop the perovskite films. The addition of thermally stable Cs cation fills in the perovskite crystal lattice and eliminates the formation of metallic Pb caused by the degradation of FA cation during the evaporation process. The tri-source co-evaporation strategy significantly promotes the phase transition from yellow δ-phase FAPbI3 to black α-phase FACsPbI3, fostering smooth, uniform, and pinhole-free perovskite films with higher crystallinity and fewer defects. On this basis, the resulting NIR-PeLED based on FACsPbI3 yields a maximum EQE of 10.25%, which is around sixfold higher than that of FAPbI3-based PeLEDs. Our work demonstrates a reliable and effective strategy to achieve α-FAPbI3 via thermal evaporation and paves the pathway toward highly efficient perovskite optoelectronic devices for future commercialization.

Nano-Micro Letters2025DOI: 10.1007/s40820-024-01600-4

Tailoring the Reversible Phase Transition of Perovskite Nanofiber Electrodes for High-Performance and Durable Reversible Solid Oxide Cells

Reversible solid oxide cells (RSOCs) are capable of converting various energy resources, between electricity and chemical fuels, with high efficiency and flexibility, making them suitable for grid balancing and renewable energy consumption. However, the practical application of RSOCs is still limited by the insufficient activity and stability of the electrodes in different operating modes. Herein, a highly efficient symmetrical electrode composed of La0.3Sr0.6Ti0.1Co0.2Fe0.7O3−δ (LSTCF) nanofibers and in situ exsolved Co3Fe7 nanoparticles is developed for boosting the performance of RSOCs. The reversible phase transition, high activity and stability of the electrode have been confirmed by a combination of experimental (e.g., transmission electron microscopy and X-ray absorption fine structure) and computational studies. Electrolyte-supported RSOCs with the symmetrical electrode demonstrate excellent catalytic activity and stability, achieving a high peak power density of 0.98 W cm−2 in the fuel cell mode using H2 as the fuel (or 0.53 W cm−2 using CH4 as the fuel) and a high current density of 1.09 A cm−2 at 1.4 V in the CO2 electrolysis mode (or 1.03 A cm−2 at 1.3 V for H2O electrolysis) at 800 °C while maintaining excellent durability for over 100 h.

Nano-Micro Letters2025DOI: 10.1007/s40820-025-01670-y

Thin and Flexible Breeze-Sense Generators for Non-Contact Haptic Feedback in Virtual Reality

In the realm of virtual reality (VR), haptic feedback is integral to enhance the immersive experience; yet, existing wearable devices predominantly rely on skin contact feedback, lacking options for compact and non-contact breeze-sense feedback. Herein, we propose a compact and non-contact working model piezoelectret actuator for providing a gentle and safe breeze sensation. This easy-fabricated and flexible breeze-sense generator with thickness around 1 mm generates air flow pressure up to ~163 Pa, which is significantly sensed by human skin. In a typical demonstration, the breeze-sense generators array showcases its versatility by employing multiple coded modes for non-contact information transmitting. The thin thinness and good flexibility facilitate seamless integration with wearable VR setups, and the wearable arrays empower volunteers to precisely perceive the continuous and sudden breeze senses in the virtual environments. This work is expected to inspire developing new haptic feedback devices that play pivotal roles in human–machine interfaces for VR applications.

Nano-Micro Letters2025DOI: 10.1007/s40820-025-01649-9

Zn(TFSI)2-Mediated Ring-Opening Polymerization for Electrolyte Engineering Toward Stable Aqueous Zinc Metal Batteries

Practical Zn metal batteries have been hindered by several challenges, including Zn dendrite growth, undesirable side reactions, and unstable electrode/electrolyte interface. These issues are particularly more serious in low-concentration electrolytes. Herein, we design a Zn salt-mediated electrolyte with in situ ring-opening polymerization of the small molecule organic solvent. The Zn(TFSI)2 salt catalyzes the ring-opening polymerization of (1,3-dioxolane (DOL)), generating oxidation-resistant and non-combustible long-chain polymer (poly(1,3-dioxolane) (pDOL)). The pDOL reduces the active H2O molecules in electrolyte and assists in forming stable organic–inorganic gradient solid electrolyte interphase with rich organic constituents, ZnO and ZnF2. The introduction of pDOL endows the electrolyte with several advantages: excellent Zn dendrite inhibition, improved corrosion resistance, widened electrochemical window (2.6 V), and enhanced low-temperature performance (freezing point = −34.9 °C). Zn plating/stripping in pDOL-enhanced electrolyte lasts for 4200 cycles at 99.02% Coulomb efficiency and maintains a lifetime of 8200 h. Moreover, Zn metal anodes deliver stable cycling for 2500 h with a high Zn utilization of 60%. A Zn//VO2 pouch cell assembled with lean electrolyte (electrolyte/capacity (E/C = 41 mL (Ah)−1) also demonstrates a capacity retention ratio of 92% after 600 cycles. These results highlight the promising application prospects of practical Zn metal batteries enabled by the Zn(TFSI)2-mediated electrolyte engineering.

New Carbon Materials (新型炭材料)2025DOI: 10.1016/S1872-5805(NCM2024-39-04-01)

A review of the catalytic preparation of mesophase pitch

Because of its high purity and excellent orientation, mesophase pitch is a superior precursor for high-performance carbon materials. However, the preparation of top-notch mesophase pitch faces challenges. Catalytic polycondensation at low temperatures is more favorable for synthesizing mesophase pitch, because it circumvents the high-temperature free radical reaction of other thermal polycondensation approaches. The reaction is gentle and can be easily controlled. It has the potential to significantly improve the yield of mesophase pitch and easily introduce naphthenic characteristics into the molecules, catalytic polycondensation is therefore a preferred method of synthesizing highly spinnable mesophase pitch. This review provides a synopsis of the selective pretreatment of the raw materials to prepare different mesophase pitches, and explains the reaction mechanism and associated research advances for different catalytic systems in recent years. Finally, how to manufacture high-quality mesophase pitch by using a catalyst-promoter system is summarized and proposed, which may provide a theoretical basis for the future design of high-quality pitch molecules.

Transactions of Nonferrous Metals Society of China (中国有色金属学报)2025DOI: 10.1016/S1003-6326(25)66982-2

Improving mechanical properties of Cu/CNTs composites by incorporating nanotwins

To exploit the combined strengthening effects of nanotwins and carbon nanotubes (CNTs) in Cu matrix composites, the nanotwins with a width ranging from 3 to 30 nm were incorporated into the CNTs-reinforced Cu matrix composites using cryogenic rolling and optimizing the initial particle size of the raw Cu powders. The formation of nanotwins in the Cu matrix composite reinforced by only 0.2 wt.% CNTs is accompanied by the increased dislocation density and refined Cu grain size, resulting in much better strength−ductility synergy than the referenced composite without significant nanotwins formation. The analysis of strengthening and toughening mechanisms demonstrates that the strength increment mainly derives from grain refinement strengthening, dislocation strengthening, and nanotwin strengthening. The strength increment from the contribution of the nanotwins accounts for 19.9% of the overall strength increment for the composite. Meanwhile, the retention of good tensile ductility can be reasonably explained by the increased dislocation accommodation ability due to the formed nanotwins and the decreased induced dislocation proliferation.

Chinese Journal of Mechanical Engineering2025DOI: 10.1186/s10033-025-01280-0

Biomimetic Desert Beetle Microgrinding Tool Flow-field Model and Processability Evaluation

Microgrinding is widely used in clinical bone surgery, but saline spray cooling faces technical challenges such as low wettability at the microgrinding tool–bone interface, easy clogging of the microgrinding tools, and high grinding temperatures. These issues can lead to bone necrosis, irreversible thermal damage to nerves, or even surgical failure. Inspired by the water-trapping and directional transportation abilities of desert beetles, this study proposes a biomimetic desert beetle microgrinding tool. The flow-field distribution directly influences the convective heat transfer of the cooling medium in the grinding zone, which in turn affects the grinding temperature. To address this, a mathematical model of the two-phase flow field at the biomimetic microgrinding tool–bone interface is developed. The results indicate an average error of 14.74% between the calculated and experimentally obtained airflow field velocities. Next, a biomimetic desert beetle microgrinding tool is prepared. Experiments with physiological saline spray cooling were conducted on fresh bovine femur bone, which has mechanical properties similar to human bone. Results show that, compared with conventional microgrinding tools, the biomimetic tools reduced bone surface temperature by 21.7%, 13.2%, 5.8%, 20.3%, and 25.8% at particle sizes of 150#, 200#, 240#, 270#, and 300#, respectively. The surface morphology of the biomimetic microgrinding tools after grinding is observed and analyzed, revealing a maximum clogging area reduction of 23.0%, which is 6.1%, 6.0%, 10.0%, 15.6%, and 9.5% less than that observed with conventional tools. Finally, this study unveils the dynamic mechanism of cooling medium transfer in the flow field at the biomimetic microgrinding tool–bone interface. This research provides theoretical guidance and technical support for clinical bone resection surgery.

Chinese Journal of Mechanical Engineering2025DOI: 10.1186/s10033-025-01293-9

Isogeometric Collocation Method for Random Field Discretization Based on Adaptive Moment Abscissae

The discretization of random fields is the first and most important step in the stochastic analysis of engineering structures with spatially dependent random parameters. The essential step of discretization is solving the Fredholm integral equation to obtain the eigenvalues and eigenfunctions of the covariance functions of the random fields. The collocation method, which has fewer integral operations, is more efficient in accomplishing the task than the time-consuming Galerkin method, and it is more suitable for engineering applications with complex geometries and a large number of elements. With the help of isogeometric analysis that preserves accurate geometry in analysis, the isogeometric collocation method can efficiently achieve the results with sufficient accuracy. An adaptive moment abscissa is proposed to calculate the coordinates of the collocation points to further improve the accuracy of the collocation method. The adaptive moment abscissae led to more accurate results than the classical Greville abscissae when using the moment parameter optimized with intelligent algorithms. Numerical and engineering examples illustrate the advantages of the proposed isogeometric collocation method based on the adaptive moment abscissae over existing methods in terms of accuracy and efficiency.

Journal of Central South University2025DOI: 10.1007/s11771-025-6155-4

Accelerated physics-based simulations of train aerodynamics using machine learning libraries

This paper presents the application of a novel AI-based approach, Neural Physics, to produce high-fidelity simulations of train aerodynamics. Neural Physics is built upon convolutional neural networks (CNNs), where the weights are explicitly determined by classical numerical discretisation schemes rather than by training. By leveraging the power of AI technology, this recent approach results in code that can run easily on GPUs and AI processors, achieving high computational speed without sacrificing accuracy. The approach uses an implicit large eddy simulation method based on a non-linear Petrov-Galerkin method to model the unresolved turbulence. Furthermore, for higher-order finite elements, the convolutional finite element method (ConvFEM) is used, which greatly simplifies the implementation of higher-order elements within the NN4DPEs approach. We demonstrate the capability of Neural Physics by simulating a freight Locomotive Class 66 and a partially loaded freight train operating in an open field environment with and without cross wind. This is the first time that ConvFEM has been applied to high-speed fluid flow problems in complex geometries. The results are validated against existing numerical results and experimental measurements, and show good agreement in terms of pressure and velocity distributions around the train body.

Int. Journal of Minerals, Metallurgy and Materials (矿物冶金与材料学报)2025DOI: 10.1007/s12613-024-3050-1

Adaptable liquid metal putty for high electromagnetic shielding

The development of stretchable conductors with high deformation, conductivity, and thermal conductivity using liquid metal (LM) has sparked widespread interest in the fields of flexible electronics, electromagnetic interference (EMI), and multifunctional materials. However, fabricating desirable shielding materials by directly coating LMs on soft polymer substrates remains a challenge because of the huge surface tension and weak wettability of LMs. In this study, Ga-based composite paste is prepared from a mixture of Ga and diamond nonmetallic particles through ultrasonic fragmentation. At various temperatures, the resulting LM composite putty (LMP) exhibits soft and hard properties and can thus be molded into specific shapes according to application needs. In addition, the composite can be easily coated onto polymer substrates, such as thermoplastic polyurethane (TPU) elastomer. The fabricated LMP–TPU exhibits an impressive shape deformation capacity of 1100%, demonstrating exceptional tensile properties and achieving electromagnetic interference–shielding effectiveness of up to 52 dB. Furthermore, it retains an ultrahigh conductivity of 20000 S/m, even under a strain of 600%. This feature further makes it a highly competitive multifunctional material.

Int. Journal of Minerals, Metallurgy and Materials (矿物冶金与材料学报)2025DOI: 10.1007/s12613-024-3061-y

Mechanisms and interactions in the reduction of Fe2O3 by H2/CO mixed gas: Atomic insights from ReaxFF molecular dynamics simulations and experiments

The experiment explored the Fe2O3 reduction process with H2/CO mixed gas and confirmed a promoting effect from CO when its volume proportion in mixed gas is 20% at 850°C. The ReaxFF molecular dynamics (MD) simulation method was used to observe the reduction process and provide an atomic-level explanation. The accuracy of the parameters used in the simulation was verified by the density functional theory (DFT) calculation. The simulation shows that the initial reduction rate of H2 is much faster than that of CO (from 800 to 950°C). As the reduction proceeds, cementite, obtained after CO participates in the reduction at 850°C, will appear on the iron surface. Due to the active properties of C atoms in cementite, they are easy to further react with the O atoms in Fe2O3. The generation of internal CO may destroy the dense structure of the surface layer, thereby affecting the overall reduction swelling of Fe2O3. However, excess CO is detrimental to the reaction rate, mainly because of the poor thermodynamic conditions of CO in the temperature range and the molecular diffusion capacity is not as good as that of H2. Furthermore, the surface structures obtained after H2 and CO reduction have been compared, and it was found that the structure obtained by CO reduction has a larger surface area, thus promoting the subsequent reaction of H2.

Nano-Micro Letters2025DOI: 10.1007/s40820-024-01577-0

Anti-Swelling Polyelectrolyte Hydrogel with Submillimeter Lateral Confinement for Osmotic Energy Conversion

Harvesting the immense and renewable osmotic energy with reverse electrodialysis (RED) technology shows great promise in dealing with the ever-growing energy crisis. One key challenge is to improve the output power density with improved trade-off between membrane permeability and selectivity. Herein, polyelectrolyte hydrogels (channel width, 2.2 nm) with inherent high ion conductivity have been demonstrated to enable excellent selective ion transfer when confined in cylindrical anodized aluminum pore with lateral size even up to the submillimeter scale (radius, 0.1 mm). The membrane permeability of the anti-swelling hydrogel can also be further increased with cellulose nanofibers. With real seawater and river water, the output power density of a three-chamber cell on behalf of repeat unit of RED system can reach up to 8.99 W m−2 (per unit total membrane area), much better than state-of-the-art membranes. This work provides a new strategy for the preparation of polyelectrolyte hydrogel-based ion-selective membranes, owning broad application prospects in the fields of osmotic energy collection, electrodialysis, flow battery and so on.