As an ultrawide-bandgap semiconductor for extreme-environment applications, ,B-Ga2O3 exhibits remarkable radiation resistance. However, its behavior under extreme electron irradiation exceeding conventional energy regimes remains largely unexplored. Here, we combine 10 MeV electron irradiation (fluences: 1 & times; 1017 and 5 & times; 1017 cm-2), first principles calculation, and machine-learning molecular dynamics (ML-MD) simulations parameterized to match these conditions to systematically reveal the anisotropic structural limits and phase evolution mechanisms of ,B-Ga2O3. Electron irradiation induces pronounced anisotropic lattice degradation, electronic and optical responses across different crystal planes (100), (010), (001), and (2 & strns; 01). The (100) plane undergoes severe near-surface degradation via the collapse of GaO4 tetrahedra, evidenced by the disappearance of the B(2) g , A(8g) and A(9) g Raman modes. For the (010) orientation, the pronounced channeling effect reduces scattering cross-sections and favors dispersed point defects, broadening the bulk X-ray diffraction (XRD) rocking curve full width at half maximum (FWHM) from similar to 42 to over 155 arcsec. Across the four planes, irradiation induces a similar to 690 nm infrared emission while differentially suppressing their intrinsic blue-violet luminescence. The (001) plane demonstrates the highest overall tolerance. ML-MD simulations reveal that electron irradiation-generated point defects reorganize into a low-fraction, dispersed gamma-phase inclusion that remains structurally coherent with the defective ,B-phase matrix. These insights into the orientation-dependent structural, electronic, optical properties, and phase evolution establish a strategic framework for designing radiation-resistant ,B-Ga2O3 devices with sustained performance under extreme conditions. (c) 2026 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
Background China has invested heavily in accessible facilities, but research on their effectiveness is limited. Methods This study randomly sampled street view images in Beijing, analysing 6904 images to assess accessibility, usability, and observed use rates of tactile paving and curb ramps for pedestrians with disabilities. On-site observations of tactile paving and standardized wheelchair-based assessments were also conducted. Results The findings reveal that tactile paving and curb ramps are widely available in Beijing. However, over 10% of these facilities are either damaged or obstructed, suggesting their poor usability. Moreover, the study identified low observed use rates for tactile paving and wheelchair-accessible facilities in Beijing. The Capability Approach and Person-Environment fit theory suggest this may stem from a fragmented accessible environment, where coverage does not translate to effective real-world use. Conclusions Despite widespread availability, discontinuous, non-compliant, and poorly maintained accessible facilities lead to their poor usability and low observed use rates in Beijing, highlighting the need for cohesive accessible environments. Limitation and implications This study is limited by its focus on Beijing, reliance on static street-view images that cannot capture temporal patterns of facility use, and the absence of participants with disabilities. Nevertheless, the research advances the understanding of the accessible environment, illustrating the significant potential for using street view photos combined with complementary data sources to provide extensive, readily understandable data for future accessibility studies.
Preventing filament tearing and fracture during high-efficiency 3D concrete printing remains a significant challenge, given their potential to compromise structural integrity and manufacturing efficiency. This study proposes a novel gravity-driven fresh-state tensile test, adapted from the "slug test", for in-situ quality control of 3D-printed fiber-reinforced cementitious composites (FRCC). By analyzing the fracture response of extruded filaments, two quantitative indicators, fresh-state tensile strength (sigma(fresh)) and strain (epsilon(fresh)), were established, potentially linking to the resistance against filament tearing during high-speed printing. The influences of processing method (casting vs. extrusion) and nozzle geometry (area, shape, and thickness) were investigated. Results show that optimizing nozzle geometry significantly enhanced filament integrity. Compared with casting, extrusion and further reducing nozzle area (380 to 150 mm(2)) and thickness (10 to 3 mm) increased fresh-state tensile strength by 62.1% (6.52 to 10.57 kPa) and strain by 60.7% (12.2% to 19.6%). These improvements effectively suppressed filament fracture during high-speed printing, increasing critical travel speed from 105.8 to 139.2 mm/s and reducing defect index from 0.16 to 0.02. The advantages established in the fresh state were ultimately preserved after hardening, yielding a 59.1% increase in ultimate tensile strength (to 9.45 MPa) and a 117.8% increase in strain (to 11.04%). The improvements might be attributed to enhanced fiber alignment (47.7 degrees to 11.6 degrees) induced by nozzle extrusion, which improves reinforcement efficiency, especially fresh-state resistance against filament fracture. This study establishes a potential link among fresh-state tensile response, printability, and hardened performance, providing an in-situ quality control protocol for 3D printing of FRCC.
Amid the global push for sustainable construction, bamboo has been widely studied as a rapidly renewable, high-performance building material. This paper reviews the published literature on bamboo’s journey from plant to structural component. The review first examines the fundamental botanical characteristics of bamboo, explaining the relationship between its hierarchical structure—from molecular to cellular levels—and its mechanical properties. It then transitions to an analysis of sustainable forestry, harvesting practices, the structural uses of round bamboo, and the manufacturing processes for engineered bamboo products, such as glued laminated bamboo and bamboo scrimber. Critical performance challenges are addressed by evaluating modern treatment methods that enhance durability, dimensional stability, and fire resistance. Structural applications are explored in detail, covering traditional building typologies, innovative connection systems, and the emerging potential for bamboo in mid- and high-rise as well as long-span structures. The life cycle perspective is completed by examining end-of-life scenarios, including reuse, recycling, and energy recovery. Ultimately, the review situates bamboo within the global context by examining resource distribution, trade, and the policy frameworks required to promote its widespread adoption. By consolidating research across multiple disciplines, this paper highlights the significant potential of bamboo to contribute to a low-carbon built environment. It concludes that a holistic, science-based approach is essential for overcoming remaining challenges and fully integrating this versatile material into modern construction practices.
The Tal-Vardy construction algorithm is a polar code construction method designed based on the scheduling of successive cancellation (SC) decoding. It offers controllable accuracy and flexible construction performance. However, the algorithm suffers from high computational complexity, which increases exponentially with improved accuracy, resulting in low construction efficiency and limited practical applicability, especially for real-time wireless communication scenarios. To address this issue, this paper proposes a simplified Tal-Vardy construction algorithm combined with the First Neighbor Clustering (FINCH) algorithm, referred to as the TV-FINCH construction method. This approach significantly improves construction efficiency and reduces construction latency with minimal impact on construction performance. We first analyze the source of the high complexity in the Tal-Vardy algorithm and identify the inefficiency of the symbol merging process as the primary cause. Further investigation reveals that this process essentially resembles a low-efficiency hierarchical clustering procedure. Motivated by this insight, we introduce the FINCH clustering algorithm–known for its low computational cost and strong clustering performance–into the symbol merging stage. This transforms the original process into a more efficient one by clustering all symbols multiple times followed by a single merging step. Experimentally, our proposed TV-FINCH construction method improves construction efficiency by a factor of 2.2 to 3, while maintaining comparable performance to the Tal-Vardy.
