Vol 7 No 2 (2025)

• Analysis of Common Casting Defects and Process Countermeasures

  Qi-Hua Liu

  In the casting production process, casting quality is of critical importance. This paper investigates common casting defects, including porosity-related defects, surface and internal inclusions, crack-related defects, and shape and dimensional defects. The causes of these defects are analyzed from multiple perspectives, such as materials, process design, operating equipment, and environmental and storage conditions. Corresponding process countermeasures are proposed for different types of defects, including optimization of the gating system, improvement of sand mold and sand core quality, structural optimization, and control of cooling rates. This study provides effective guidance for improving casting quality, reducing defect occurrence, lowering production costs, and enhancing production efficiency.

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• Application of Standardized Agricultural Implement Interface Design in Multi-Implement Combined Operations

  Heng Wang

  The development of precision agriculture and smart agriculture has imposed higher requirements on agricultural production, making multi-implement combined operations an inevitable trend. However, the current agricultural implement market is highly fragmented, and the lack of universality and interoperability among different implements severely constrains the flexibility and efficiency of collaborative operations. Focusing on standardized interface design for agricultural implements, this paper first analyzes the technical connotations, current status, and challenges of multi-implement combined operations, identifying interface incompatibility as the primary bottleneck. It then systematically examines the overall architecture of standardized interfaces, elaborating on the design principles, key technologies, and standard specifications of sub-interfaces from four dimensions: mechanical, hydraulic, electrical, and information communication. On this basis, a collaborative operation model based on standardized interfaces is constructed. Finally, future development trends toward intelligence, modularization, and platformization are discussed, and corresponding policy recommendations and technical pathways are proposed. The results indicate that establishing and promoting a scientific and unified interface system is critical to enabling multi-implement collaborative operations and is of great significance for the mechanized and intelligent transformation of agriculture.

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• Performance Optimization of Crystalline Silicon Solar Cells Based on a Novel Passivated Contact Structure

  Rong Su, Yun-Sha Zhang, Jin-Feng Deng

  With the global energy transition and the advancement of the “dual-carbon” targets, photovoltaic power generation, as one of the major clean and renewable energy sources, has placed increasing emphasis on improving the efficiency and reducing the cost of its core device—the crystalline silicon solar cell. On the basis of the currently mainstream Passivated Emitter and Rear Cell (PERC) technology, further breakthroughs in efficiency are urgently required to overcome existing performance bottlenecks, which calls for innovative optimization of passivated contact structures. This study focuses on a novel passivated contact structure based on a silicon oxynitride (SiOₓNᵧ) composite dielectric passivation layer, and systematically presents its design principles, fabrication processes, performance characterization, and industrial-scale verification. The results demonstrate that by introducing multilayer composite passivation and anti-reflection films on both the front and rear sides of the cell—particularly by exploiting the combined advantages of silicon oxynitride, which integrates the excellent anti-reflection properties of silicon nitride (SiNₓ) with the superior field-effect passivation capability of silicon dioxide (SiO2)—the surface recombination velocity can be effectively reduced, minority carrier lifetime enhanced, short-wavelength spectral response improved, and long-wavelength reflection mitigated. Experimental results indicate that this novel structure can achieve an absolute conversion efficiency gain of more than 0.1% on conventional monocrystalline PERC production lines, while simultaneously improving reliability parameters such as resistance to potential-induced degradation (PID). This work provides a practical and feasible technological pathway for breaking the efficiency limits of crystalline silicon solar cells and achieving cost reduction and performance enhancement in industrial applications.

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• Analysis of Influencing Factors on the Performance of Precision Casting Wax

  Hai-Qiang Zhou

  Precision casting wax is a key material in investment casting, and its performance determines the accuracy and surface quality of the castings. This study systematically investigates the effects of filler type, dosage, and component compatibility on the fluidity, mechanical properties, thermal stability, and dimensional accuracy of a paraffin-resin filled wax system. Results indicate that sebacic acid significantly enhances the comprehensive performance of the base wax. At a 30% dosage, the rotational viscosity reaches 504.2 mPa·s, flexural strength increases to 5.02 MPa, and linear shrinkage decreases to 0.67%. Sebacic acid regulates crystallization behavior through synergistic nucleation and volume effects, with X-ray diffraction and scanning electron microscopy confirming physical mixing and good compatibility among components. Thermal analysis reveals limited impact of filler addition on thermal stability. This research provides a theoretical foundation for the formulation design and process optimization of precision casting waxes.

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• Symmetrical Finite Element Model for Out-of-Plane Crushing of Nomex Honeycomb Structure

  Wan Luqman Hakim Wan A Hamid, Mohd Sultan Ibrahim Shaik Dawood, Yulfian Aminanda

  The computational cost of Finite Element (FE) simulation of a honeycomb structure under compression is significantly high due to the large number of cell walls, frequent wall-to-wall contacts, and large deformations during loading. To address this, a symmetrical FE model was modelled and simulated to predict the crushing behaviour of a Nomex honeycomb under quasi-static axial compression, significantly reducing computational demand. The FE model’s force-displacement response, crushing load (13.3 N), absorbed energy (69.6 mJ), and fold formation (9 folds) showed good agreement with experimental tests, confirming its reliability as a design tool. Beyond structural validation, this research demonstrates the potential of flexible honeycomb structures in aerospace applications, where their lightweight, energy-absorbing, and adaptive characteristics make them ideal for impact resistance, crashworthiness, and morphing components. By enabling efficient modelling and sustainable design, the study supports the advancement of aerospace structures that enhance safety, minimize resource consumption, and contribute to both wealth preservation and the protection of human life.

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