Recently, the Shaanxi Provincial Department of Education and the Shaanxi Provincial Academic Degrees Committee announced the list of 2025 Shaanxi Excellent Doctoral Dissertations. Xi'an Jiaotong University has 25 dissertations selected, including 2 from the School of Aerospace Engineering.

Shaanxi Excellent Doctoral Dissertationsaward recognizedoctoral works with outstanding innovation and academic value. In the past five years, the school has achieved steady progress in postgraduate training, winning 14 provincial excellent doctoral dissertations, 26 university-level excellent doctoral dissertations, and 26 university-level excellent master's dissertations.

The school willupholdthe fundamental task of fostering virtue through education, reform postgraduate training mechanisms, and support high-quality talent development with large teams, platforms, and projects, to continuously produce high-quality academic achievements.

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Paper 1: Multi-scale Mechanical Behaviors and Strengthening and Toughening Strategies for Graphene Assemblies

Author: Liu Jingran | Advisor: Prof. Liu Yilun | Discipline: Mechanics

Monolayer graphene exhibits exceptional strength and conductivity, but its macroscopic assemblies (fibers, films, aerogels) often suffer from degraded mechanical performance due to weak van der Waals interactions between layers. This work systematically investigates the multi-scale mechanical behaviors of graphene assemblies, focusing on interlayer cross-linking, microporous structures, and layered composites. Key innovations include:

A self-healing nonlinear mechanical model for interlayer cross-linked graphene, revealing a "break-rebuild" mechanism that enhances both strength and toughness.

A compression failure mechanism of microporous graphene driven by interlayer sliding, where reversible sliding behavior explains energy dissipation hysteresis.

A "fusion-splitting" strategy for graphene oxide fibers to produce high-strength thick fibers while remaining re-splittable.

A "continuous break-through" model for graphene/polymer composites, achieving simultaneous improvements in strength and toughness.

Paper 2: Enhanced Flexoelectric Effect and Flexoelectrets

Author: Wen Xin | Advisor: Prof. Shen Shengping | Discipline: Aerospace Science and Technology

Flexoelectricity, a strain gradient-induced electromechanical coupling effect, holds promise for next-generation energy converters but faces challenges such as low coefficients, nanoscale limitations, and temperature sensitivity. This work addresses these issues through three complementary strategies:

The proposal of "flexoelectrets," a concept accompanied by a theoretical model that boosts the flexoelectric coefficient of soft materials by two orders of magnitude.

The demonstration of a macroscopic flexoelectric actuator, achieving millimeter-scale flexoelectric deformation.

A method to enhance the temperature stability of flexoelectric materials by leveraging the positive correlation between flexoelectric and dielectric coefficients, enabling reliable operation in variable-temperature environments.