The continuous advancement of integrated circuit (IC) technology and the constant miniaturization of device feature sizes have placed higher demands on the electrical, thermal, and reliability performance of semiconductor materials. This paper traces the development history of core semiconductor materials in IC manufacturing, following the technological trajectory from the first to the fourth generation. It analyzes their current applications and research progress in material preparation methods such as epitaxial growth and thin-film processing. The research shows that silicon-based semiconductors remain the core foundational material for IC manufacturing; second-generation compound semiconductors, represented by gallium arsenide and indium phosphide, have irreplaceable advantages in radio frequency and optoelectronic fields; third-generation wide-bandgap semiconductors, centered on silicon carbide and gallium nitride, are in the accelerated industrialization phase; and fourth-generation ultra-wide-bandgap semiconductors demonstrate enormous application potential in ultra-high voltage and ultra-high frequency applications. This paper points out that different generations of semiconductor materials will coexist and complement each other for a considerable period of time, jointly meeting the diverse performance requirements of ICs for high-frequency, high-voltage, and low-power consumption.

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With the environmental problems caused by traditional plastic packaging becoming increasingly serious, degradable packaging films have attracted growing attention in the fields of food packaging and preservation. Compared with conventional petroleum-based plastics, bio-based films prepared from natural polymers show advantages such as renewability, biodegradability, environmental friendliness and potential food-preservation functions. Focusing on cellulose, starch, chitosan and carrageenan as well as their derivatives and composite films, this paper sorts out their basic material characteristics, film-forming properties and functional advantages. It further summarizes several common preparation methods such as solution casting, extrusion blown film, coating, electrospinning, multilayer compounding and hot pressing. In addition, the applications of degradable composite films in meat preservation, fruit preservation and paper-based food packaging are discussed. By integrating material selection, processing methods and practical application, this paper aims to provide useful references for the development of bio-based composite films in the fields of food preservation and green packaging.

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With high electrical conductivity and tunable surface chemistry, MXenes, a class of two-dimensional transition metal carbides, nitrides, and carbonitrides, have been employed in energy storage, electromagnetic interference shielding, and catalysis. However, synthesis routes strongly influence their structural features, surface terminations, and functional properties, and the effects of different preparation strategies have not been fully clarified. Accordingly, this paper compares six major MXene preparation strategies, including HF etching, LiF/HCl in situ etching, alkali-hydrothermal synthesis, electrochemical exfoliation, Lewis acid molten salt etching, and bottom-up direct growth, by linking etchant chemistry with surface termination evolution and defect formation. The effects of these strategies on yield, flake size, electrical conductivity, and dominant defect types are systematically analyzed. In addition, an Al-assisted solid-state A-site extraction route for Ti 2 SnC is evaluated through experimental evidence of thermally driven Sn extraction into Al substrates at 650 °C and spontaneous Sn whisker growth. The comparison shows that etchant-induced defects limit top-down MXene synthesis, whereas fluoride-free routes enable diverse surface terminations. Moreover, solid-state A-site extraction provides an alternative to conventional chemical etching.

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Support structures in additive manufacturing consume additional material and build time, and damage the contact surface after removal. The build orientation determines which surfaces become overhangs before slicing, and is the lowest-cost intervention point, but the orientation space is continuous and the objective is highly non-convex, so neither the default orientation nor grid trial placements can reliably locate the optimal region. This paper expresses build-orientation selection as a bi-objective optimisation problem of support volume and build height, solved by a multi-start NSGA-II with axis-seeded initialisation and compared against area-uniform spherical grid enumeration at a matched evaluation budget on 120 real printable models from Thingi10K. Among the 84 models that require support under the as-uploaded orientation, optimisation reduced the median support volume by 69.0% (interquartile range 3.5% to 97.4%, p<0.001), while 16 models did not improve, so the benefit depends strongly on the specific geometry. With the grid given slightly more evaluations, the normalised hypervolume of NSGA-II was no less than that of the grid on 112 models (p<0.001). The two objectives were negatively correlated within all fronts, so the trade-off genuinely exists. The reduction is sensitive to the critical overhang angle: at 60° the median reduction is only 1.4%. This paper gives a budget-matched comparison protocol and quantifies the applicable boundary of the method's benefit.

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