About

Jiefang Li is a Research Associate Professor in the Department of Materials Science and Engineering at Virginia Tech. His research interests include piezoelectric and dielectric materials, magnetic shape memory alloys, interferometry and ellipsometry, reciprocal phase space mapping, thin-layer deposition by laser ablation, and electrical and optical measurement technologies. He holds a B.S. in Physics from Shanghai Teachers University, an M.S. in Physics from the University of Missouri - Rolla, and a Ph.D. in Solid State Science from Pennsylvania State University.

Research topics

• Physics
• Quantum mechanics
• Computer Science
• Condensed matter physics
• Artificial Intelligence
• Remote sensing
• Computer vision
• Nanotechnology
• Geography
• Materials science
• Telecommunications

Selected publications

• Preparation and Performance Study of Transparent Fluorine-Free Hydrophobic Coating

  Protection of Metals and Physical Chemistry of Surfaces · 2025-04-01

  article1st authorCorresponding

  In recent years, transparent anti-fouling coatings have attracted significant attention due to their potential applications in various fields. However, the development of multifunctional transparent anti-fouling coatings that meet practical requirements without compromising their properties remains a major challenge. This paper presents an innovative approach to address this issue by combining self-cleaning and durability through the incorporation of specific functional materials. Polydimethylsiloxane (PDMS) and methyl o-aminobenzoate (MA) were introduced to achieve these desired properties, respectively. Additionally, bisphenol A diglycidyl ether (BADGE) and 1,3-bis(3-aminopropyl)tetramethyldisiloxane (TMDS) were employed as coating substrates to enhance the mechanical strength of the coating. The structural composition, elemental analysis, and surface morphology of the coatings were thoroughly characterized using advanced techniques. The hydrophobicity, optical transparency, self-cleaning ability, and durability of the coatings were extensively evaluated. Experimental results demonstrated that the developed fluorine-free transparent hydrophobic coating exhibited excellent performance across multiple criteria: it showed outstanding hydrophobicity and transparency, superior self-cleaning capability, exceptional resistance to wear, water shock, and strong acid and alkali properties.

  PublisherDOI

• Effects of MAPK Homologous Genes on Chemotaxis and Egg Hatching in Meloidogyne incognita

  Pathogens · 2025-12-16 · 2 citations

  articleOpen access

  Root-knot nematodes, known for their broad host range and the challenges associated with their control, cause significant losses in global agricultural productivity. The mitogen-activated protein kinase (MAPK) pathway amplifies signals through a phosphorylation cascade to regulate downstream transcription factors or effector proteins, which is essential for maintaining normal physiological functions in nematodes. This study presents a comprehensive characterization of the MAPK signaling cascade regulatory network in Meloidogyne incognita, elucidating the regulatory roles of Mi-let-60, Mi-lin-45, Mi-mek-2, and Mi-mpk-1 in host chemotaxis and egg hatching behavior. Importantly, RNAi-mediated silencing of Mi-mpk-1 resulted in a 17-fold increase in egg hatching rate and significantly impaired chemotactic responses while silencing of Mi-let-60 led to a marked reduction in root gall formation and egg mass production. These results not only confirmed the evolutionary conservation of this pathway but also identified a feedback regulation mechanism unique to parasitic nematodes. These findings provide valuable insights for future research on signal transduction pathways and the sustainable management of root-knot nematodes.

  PublisherOA PDFDOI

• The Wear-Resistant Self-Cleaning Interface Prepared with Silica Sol Through Sol-Gel Method

  Glass Physics and Chemistry · 2024-06-01

  article1st author

  Self-cleaning materials played an important role in our daily life, but there remained some critical challenges such as complex fabrications, non-transparency, and poor long-term stability, which limited their applications. In this paper, acid-base silica sol and alkali-based silica sol were prepared by sol-gel method, with ethyl orthosilicate as the precursor. The two silica sols were mixed by different proportions. The mixed silica sol was evenly coated on the surface of the pretreated glass slide, and then modified by the low surface energy substance HDTMS and QX-18 fluorocarbon nanocoating, and finally prepared a hydrophobic and wear-resistant transparent coating. The surface topography of the coating was analyzed, and its acid and alkali resistance, wear resistance, self-cleaning performance and other properties were tested. The results showed that the optimal volume ratio of acid-base mixed sol was acid silica sol : alkaline silica sol = 3 : 7. The hydrophobic coating had good wear resistance, transparency, self-cleaning and acid resistance, but poor alkaline resistance.

  PublisherDOI

• Preparation of high transparent hydrophobic glass surface and its self-cleaning property

  Journal of Sol-Gel Science and Technology · 2024-06-03 · 6 citations

  article1st authorCorresponding
  PublisherDOI

• A facile approach for fabricating fluorine-free superhydrophobic cotton fabric and its self-cleaning property

  Cellulose · 2024-11-18 · 4 citations

  article
  PublisherDOI

• The Wear-Resistant Self-Cleaning Interface Prepared Through Spraying Method

  Protection of Metals and Physical Chemistry of Surfaces · 2024-08-01

  article1st authorCorresponding

  Self-cleaning materials performed a vital function in our daily lives, but there remained some critical challenges such as complex fabrications, non-transparency, and poor long-term stability, which limited their applications. In this paper, ST-402 reagent was used to construct roughness on the surface of the slide, then low surface energy materials (HDTMS, POTS) were uniformly sprayed. And finally a layer of QX-18 fluorocarbon nano coating was deposited on the surface of the coating to obtain an interface with excellent wear-resistant and hydrophobic properties. The surface micromorphology and elements of the treated interface, contact angle to water, wear resistance, acid and alkali resistance stability, and self-cleaning performance of dirt were characterized. The results showed that the hydrophobic effect of the coating prepared by using POTS as modifier was better. The hydrophobic coating had good wear resistance, transparency, self-cleaning and acid resistance, but poor alkaline resistance.

  PublisherDOI

• Causality and dynamic spillover effects of megacities on regional industrial pollution reduction

  Heliyon · 2023-03-01 · 2 citations

  articleOpen access

  Regional economic power and local environmental policies have a substantial impact on pollution reduction in urban agglomerations (UAs); however, whether megacities in UAs exert spillover effects of pollution reduction on surrounding cities remains unknown. This study presents a causal analytic framework to evaluate the spillover effects of megacities on regional industrial pollution reduction in three major UAs in China between 2005 and 2016. The interaction between industrial pollution reduction and infrastructure investment indicators was also examined. Results indicated a good fit for spatial spillover of sulfur dioxide reduction (SR) in the Pearl River Delta (PRD) and Yangtze River Delta (YRD) but not in the Beijing-Hebei-Tianjin cluster (JJJ). Spatial spillover of dust reduction (DR) was evident in the PRD and JJJ but not the YRD. Spatial analysis showed that infrastructure investment indicators, at megacity and UA levels, had short-term spillover effects on surrounding cities for DR but not SR. However, spatial spillover effects, at both the city and UA levels, were substantial over the long term. In addition, the results of the spatial-time lag analysis suggest a linear relationship between pollution control-related infrastructure investment indicators and long-term pollution reduction. This study provides new information regarding the spatial spillover effects of megacities on regional industrial pollution reduction in UAs.

  PublisherOA PDFDOI

• Realization of electron transpiration cooling: LaB6 heated by a plasma glow

  Applied Physics Letters · 2023-09-04 · 4 citations

  articleOpen access

  Electron transpiration cooling has previously been predicted to be an alternative cooling mechanism for leading edges of aerospace platforms traveling at extreme velocities, where thermoelectric materials shaped as leading edges manage heat loads. Here, thermo-electron emitting LaB6 ceramics with blunt edges were placed between two conical-shaped electrodes, and a plasma glow was ignited to heat the sample. Analysis of current–voltage (I–V) curves demonstrated that insertion of LaB6 into the plasma column resulted in an increase in the electron density of the plasma, evidencing thermally stimulated electron emission. With increasing sample temperature to 1200 K, Δne increased by ∼4 × 1010 #/cm3, the electron temperature (Te) decreased from ∼8 eV (1000 K) to 2.5 eV, and the emission begins to appear to become space charge-limited. Richardson's analysis of the temperature dependence of the electron emission in the region of ion saturation, yielded an activation energy consistent with the work function of LaB6. Modulation of the LaB6 surface temperature (ΔT = 10 K) and the plasma current (ΔI = 70 μA) under electric voltage (80 V) applied between the sample and current probe was demonstrated. The results show for the first time the feasibility of electron transpiration cooling effects under plasma conditions similar to that of aerothermal environments.

  PublisherOA PDFDOI

• Multicomponent hexaborides with low work functions by ultra-fast high temperature sintering

  Open Ceramics · 2023-09-30 · 6 citations

  articleOpen access

  A reduction of the work function (Wf) in multicomponent hexaborides has been achieved by doping with highly electropositive Ba, which enhances electron emission. Single-phase bulk multicomponent polycrystalline hexaborides of La0.5Ba0.5B6, Ce0.5Ba0.5B6, and BaB6 powders were first synthesized and then densified by ultra-fast high temperature sintering. Using a total reaction and densification time of 6 min, a density of ∼90% theoretical was reached. The UHS sintering is a resistive heating technique, which enables a high heating rate (∼103–104°C/min) to reach the synthesis/sintering temperature in a minute and facilitates in synthesizing single phase solid solution product very quickly (in 6 min). Measurements of Wf were carried out by Kelvin Probe Force Microscopy, yielding values of Wf = 2.05 ± 0.10 and 2.00 ± 0.10 for La0.5Ba0.5B6 and Ce0.5Ba0.5B6 respectively. These values of Wf are similar to those predicted by first-principles calculations. Ba-substitution is shown to be a general approach to reduce Wf (∼25%) in various multicomponent hexaborides.

  PublisherDOI

• The <i>Human Activity Radar</i> <i>Challenge:</i> Benchmarking Based on the ‘Radar Signatures of Human Activities’ Dataset From Glasgow University

  IEEE Journal of Biomedical and Health Informatics · 2023-01-30 · 31 citations

  articleOpen access

  Radar is an extremely valuable sensing technology for detecting moving targets and measuring their range, velocity, and angular positions. When people are monitored at home, radar is more likely to be accepted by end-users, as they already use WiFi, is perceived as privacy-preserving compared to cameras, and does not require user compliance as wearable sensors do. Furthermore, it is not affected by lighting conditions nor requires artificial lights that could cause discomfort in the home environment. So, radar-based human activities classification in the context of assisted living can empower an aging society to live at home independently longer. However, challenges remain as to the formulation of the most effective algorithms for radar-based human activities classification and their validation. To promote the exploration and cross-evaluation of different algorithms, our dataset released in 2019 was used to benchmark various classification approaches. The challenge was open from February 2020 to December 2020. A total of 23 organizations worldwide, forming 12 teams from academia and industry, participated in the inaugural Radar Challenge, and submitted 188 valid entries to the challenge. This paper presents an overview and evaluation of the approaches used for all primary contributions in this inaugural challenge. The proposed algorithms are summarized, and the main parameters affecting their performances are analyzed.

  PublisherOA PDFDOI

Frequent coauthors

• D. Viehland

  Virginia Tech

  257 shared

• Haosu Luo

  82 shared

• Yaojin Wang

  Nanjing University of Science and Technology

  57 shared

• Chung Ming Leung

  Harbin Institute of Technology

  49 shared

• Xin Zhuang

  Shandong University of Traditional Chinese Medicine

  46 shared

• D. Viehland

  Virginia Tech

  37 shared

• Qinhui Zhang

  34 shared

• Junqi Gao

  Shanghai Jiao Tong University

  34 shared