This study investigates the bond behavior of fabric-reinforced cementitious matrix (FRCM) composites with three common masonry substrates—solid clay bricks (SBs), perforated bricks (PBs), and concrete hollow blocks (HBs)—using knitted polyester grille (KPG) fabric. Through uniaxial tensile tests of the KPG fabric and FRCM system, along with single-lap and double-lap shear tests, the interfacial debonding modes, load-slip responses, and composite utilization ratio were evaluated. Key findings reveal that (i) SB and HB substrates predominantly exhibited fabric slippage (FS) or matrix–fabric (MF) debonding, while PB substrates consistently failed at the matrix–substrate (MS) interface, due to their smooth surface texture. (ii) Prism specimens with mortar joints showed enhanced interfacial friction, leading to higher load fluctuations compared to brick units. PB substrates demonstrated the lowest peak stress (69.64–74.33 MPa), while SB and HB achieved comparable peak stresses (133.91–155.95 MPa). (iii) The FRCM system only achieved a utilization rate of 12–30% in fabric and reinforcement systems. The debonding failure at the matrix–substrate interface is one of the reasons that cannot be ignored, and exploring methods to improve the bonding performance between the matrix–substrate interface is the next research direction. HB bricks have excellent bonding properties, and it is recommended to prioritize their use in retrofit applications, followed by SB bricks. These findings provide insights into optimizing the application of FRCM reinforcement systems in masonry structures.

The northeastern margin of the Qinghai–Tibet Plateau is an ecologically fragile region that faces severe habitat fragmentation, which directly threatens regional biodiversity conservation and ecological security. To address this challenge, this study constructed a hierarchical “source-corridor-node” ecological network for the Gannan Tibetan Autonomous Prefecture by integrating Morphological Spatial Pattern Analysis (MSPA), the Minimum Cumulative Resistance (MCR) model, landscape connectivity assessment, and gravity modeling. The key results are as follows: (1) The Gannan Yellow River Water Source Replenishment Area contains 11 core ecological source regions, which are predominantly located in the southeastern regions of Diebu County and Zhouqu County, covering a total area of 4237.81 km²; (2) Ecological resistance analysis identifies high-resistance zones concentrated in anthropogenically active river valleys and urban belts (e.g., Hezuo urban area, Awanzang Town, and the G213 corridor). Low-resistance zones are predominantly situated in protected ecological enclaves (e.g., Zhagana Geopark and Gahai Wetland Reserve); (3) A total of 55 ecological corridors were identified, with a total length of 4355.77 km. Among these, 26 were classified as key ecological corridors, primarily distributed in Diebu and Zhouqu counties in the eastern part of Gannan Prefecture. These areas feature relatively concentrated ecological sources, and the key corridors play a critical role in connecting isolated ecological patches and maintaining regional ecological connectivity. (4) Across the entire territory of Gannan Prefecture, a total of 81 first-level ecological nodes and 53 second-level ecological nodes were delineated. As the core hub of the regional ecological network in Gannan Prefecture, Diebu County encompasses 60 First-level and 41 Second-level ecological nodes, respectively. The hierarchical “source-corridor-node” ecological network constructed in this study effectively enhances the overall landscape connectivity of the area. This progressive analytical framework—integrating source identification, corridor extraction, and node diagnosis—provides a scientific basis for biodiversity conservation, territorial ecological restoration, and sustainable development in high-altitude ecologically fragile zones.

In view of the seismic performance deficiencies commonly observed in existing reinforced concrete (RC) frame structures, the application of fiber-reinforced polymer (FRP) composites for seismic strengthening has become a key technical approach to enhance the safety reserve of such structures. However, most existing studies primarily focus on the overall effectiveness of strengthening schemes, while systematic investigations on key geometric parameters, such as strengthening location and length, remain insufficient. In this paper, based on the ABAQUS finite element software and calibrated against a quasi-static test of a 1/2-scale two-story two-bay RC plane frame, refined numerical models of both unstrengthened and FRP-strengthened frames were established. Adopting a “control-variable parametric analysis” strategy and using cross-sectional dimensions as the reference, nine strengthening cases were designed with column-end FRP lengths of 0.5b, 1.5b, and 2.5b and beam-end FRP lengths of 1h, 2h, and 3h. The differential effects of FRP-strengthening lengths at beam and column ends on the seismic performance of the frame structure were revealed. The results indicate that FRP strengthening can effectively enhance the load-bearing capacity and improve the hysteretic performance of members. Nevertheless, the underlying mechanisms by which beam-end and column-end strengthening lengths affect mechanical behavior are fundamentally different: column-end FRP strengthening primarily governs the initial stiffness and load-bearing capacity, with a maximum increase in peak load of 40.7%; beam-end FRP strengthening mainly controls the post-yield stiffness degradation rate and energy dissipation capacity, achieving a peak load increase of up to 53.2%, although the marginal benefit tends to diminish with increasing length. Beam-end strengthening is the critical factor governing the transition of failure mode (from brittle joint shear failure to ductile beam-end flexural failure), while column-end strengthening plays a supplementary role in restraining the formation of column hinges and maintaining the desirable “strong column-weak beam” failure hierarchy. This study reveals the influence of FRP strengthening length on the seismic performance of structures, and to some extent addresses the deficiency of existing studies in systematic parametric analysis.

To improve renewable energy utilization and reduce fossil fuel consumption in building heating systems in Northwest China, this study proposes a solar–biogas hybrid heating system for the Jiuquan region. A dynamic simulation model was developed in TRNSYS, and multi-objective optimization was conducted using the NSGA-II algorithm. The optimization objectives were to maximize the solar fraction and minimize the initial system investment. The solar collector area, thermal storage tank volume, and biogas boiler start-up temperature were selected as decision variables. The results showed that the optimized solar fraction increased from 48.98% to 78.40% as the initial investment increased from 40,000 CNY to 80,000 CNY, although the marginal return gradually decreased. The NSGA-II algorithm generated a well-distributed Pareto front, revealing a clear trade-off between economic performance and solar energy utilization. Relative to the author-defined, proportionally scaled reference configurations, the optimized solutions increased the solar fraction by 18–21% across the examined investment levels. These improvement percentages are conditional on the adopted baseline definition. Considering both energy performance and economic feasibility, the scheme with a solar fraction of approximately 70% was identified as the compromise solution. Compared with the initial design, this scheme increased the initial investment by 15.52% and improved the solar fraction by 20.69%. These results indicate that appropriate configuration of key system parameters can substantially enhance renewable energy utilization. The proposed optimization method provides a useful reference for the design and operation of solar–biogas hybrid heating systems in Northwest China.

The building heat demand and the energy system capacity are usually designed independently in solar heating systems for rural houses in cold regions. This leads to oversized system capacity and a lack of collaborative design between the building side and the energy system side. To address these issues, a building–PVT collaborative passive–active design framework was proposed for a typical rural house in Lanzhou, Gansu Province, China. First, a dynamic building thermal model was developed in EnergyPlus. Four typical building configurations, including a baseline house, an insulated house, a sunspace house, and a sunspace house with an intelligent thermal curtain, were established. The hourly heating demand over 8760 h was obtained for each configuration. Then, the hourly building heating demand was used as the unified boundary condition to develop a dynamic PVT heating system model in MATLAB. The responses of the PVT collector area, thermal storage tank volume, and auxiliary heater capacity to building heat demand were analyzed. A CSR was further proposed to establish a quantitative relationship between building heating load reduction and PVT system capacity reduction. Finally, a collaborative multi-objective optimization was carried out using the NSGA-II with the objectives of maximizing the SF and minimizing the LCC. The TOPSIS was adopted to determine the optimal compromise solution. The results show that the integrated passive design combining a sunspace with an intelligent thermal curtain reduces the annual heating energy consumption by 44.0% compared with the baseline house. The reduction in building heat demand simultaneously decreases the required PVT system capacity. The PVT collector area, thermal storage tank volume, and auxiliary heater capacity decrease by 44.14%, 27.55%, and 25.78%, respectively. This indicates that passive building energy-saving measures significantly change the design boundary of the energy system. The proposed CSR effectively quantifies the capacity substitution effect of building-side energy saving on the PVT heating system, and the integrated passive design achieves the highest overall CSR. The multi-objective optimization generates a uniformly distributed Pareto front. The optimal compromise solution achieves an SF of 86.41% with an LCC of 8.34 × 10⁴ CNY. The recommended configuration includes a 50 mm insulation layer, a 40 m² sunspace, a 12.62 m² PVT collector area, and a 1.23 m³ thermal storage tank. Compared with the initial design, the optimized configuration significantly improves solar energy utilization while maintaining a low LCC and further reducing the required auxiliary heater capacity. This study establishes a collaborative analysis framework between building heat demand and PVT system capacity. A quantitative mapping method between building heating load and system capacity is proposed. The framework enables integrated optimization of building thermal design and energy system capacity configuration. The proposed method provides a new theoretical approach and practical guidance for the design of solar heating systems for rural houses in cold regions.

Coupled water–heat transport and water–ice phase transitions are key processes in the freeze–thaw deterioration of fractured rock, but their continuous surface-thermal manifestations remain poorly characterized. Infrared thermography was used to monitor the surface temperature fields of 100 mm saturated granite cubes containing one artificial fracture during freezing at −20 °C and subsequent natural thawing, with saturated intact specimens used for comparison. The surface 0 °C isotherm was tracked as an apparent thermal front; it was not treated as a direct measurement of the internal three-dimensional ice–water phase boundary. The fractured specimens exhibited strongly non-uniform apparent-front propagation, unlike the approximately linear behavior of intact granite. During freezing, the apparent front expanded in a fan-shaped pattern and accumulated near the fracture, whereas during thawing it propagated in a horseshoe-shaped pattern. Apparent-front velocities changed sharply near the fracture, consistent with fracture-induced redistribution of heat flow and the sensible- and latent-heat storage of fracture water. Because water content and liquid-water displacement were not measured independently, the results are interpreted as specimen-scale surface-thermal signatures rather than direct visualization of internal water migration. The findings establish a controlled laboratory benchmark for this specimen geometry and boundary condition. Extrapolation to natural fracture networks, frost-heave damage, or engineering-scale prediction requires additional tests across fracture geometries, rock types, stress states, moisture conditions, and thermal boundaries, together with internal hydraulic and mechanical measurements.