Lacquerware craftsmanship of the Western Han period is well known, yet the specific material choices and formulation techniques remain poorly understood. This study investigates two lacquer pots (dated to 186 BCE) from the Guankou cemetery in Chongqing, as a case study to explore their manufacturing characteristics. We characterised the artefacts using wood anatomical analysis, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and pyrolysis–gas chromatography–mass spectrometry (Py-GC/MS), enabling systematic analysis of wood substrates, layer sequences and material compositions. The results reveal a functional tailoring of materials: the round pot was made of lightweight poplar, whereas the flattened pot used harder, dimensionally stable crape myrtle. Structurally, the round pot exhibits a four-layer sequence (wood core, clay–ash ground with aluminosilicate fillers, base lacquer, and cinnabar-pigmented decoration), while the flattened pot has a simplified two-layer construction with lacquer directly on wood. Both artefacts utilise natural lacquer from Toxicodendron vernicifluum, but the round pot employs a pure-lacquer system, whereas the flattened pot incorporates a blend of lacquer and drying oil. These findings, based on two vessels from a single tomb, demonstrate technological diversity and suggest customised formulation in early Western Han lacquer production. This work provides empirical case-study evidence for research on craft traditions, regional manufacturing characteristics, and the history of lacquer-related materials science.
Under partial-shading conditions, landscape-oriented photovoltaic (PV) modules can exhibit dual- or multi-peak power–voltage (P–V) characteristics, which may trap conventional maximum power point tracking (MPPT) algorithms at local optima. A 60-cell full-cell PV module model incorporating bypass diodes was established, and global maximum power point tracking (GMPPT) simulations were conducted under partial-shading conditions. The model agreed well with previously obtained experimental data, with a mean absolute percentage error of 3.48% between the simulated and measured powers. An improved particle swarm optimization–incremental conductance strategy (PSO-INC) was developed by incorporating a transition stage, an irradiance-change-triggered global-search restart mechanism, and a search-direction-dependent adaptive step size. This strategy combines the global exploration capability of particle swarm optimization (PSO) with the local refinement capability of incremental conductance (INC). Thirty independent simulations with prescribed random seeds were performed for each scenario. Relative to the experimentally measured global maximum power point (GMPP), PSO-INC achieved a mean tracking efficiency of 99.20% and a mean relative error of 0.80% across the six static-shading configurations. Its mean settling time was 44.81% shorter than that of PSO. Under 25% shading, the mean tracked power was 256.23 W, exceeding the reported outputs of INC and jump-exploration incremental conductance (JEINC) by 41.95 W (19.58%) and 40.10 W (18.55%), respectively. Following irradiance transitions from 1000 to 500 W/m2 and from 1000 to 0 W/m2, the mean settling time was reduced by 53.03% and 53.05%, respectively, relative to PSO. These results demonstrate that PSO-INC improves GMPPT accuracy, settling performance, and steady-state behavior under partial-shading conditions and rapidly changing irradiance.
The oxidation and crack propagation behavior of HVOF-NiCrAlY + APS-YSZ thermal barrier coatings in a furnace cycling environment were investigated. It was found that TGO growth yields a power-law relationship, δTGO−δ0=kTGOtnTGO, with nTGO < 0.5. Crack propagation exhibits a steady-state propagation stage followed by an accelerating propagation stage, and the crack length likely has a power-law relationship with TGO thickness, amax−a0=kcrackδTGOncrack, with ncrack > 3. Although lower Cr and Y contents favor the formation and continuous growth of near-Al2O3-TGO, this might compromise the FCT life of the TBC.
This study investigated the coupled effects of petroleum coke residue (PCR) and alkali equivalent on the strength, shrinkage, and durability of alkali–activated mortars based on a ground–granulated blast–furnace slag–fly ash (GGBS–FA) system. A suitable PCR content improved compressive and flexural strength, whereas higher contents reduced strength. These trends may reflect changes in calcium– and sulfate–bearing reaction products and the concurrent reduction in FA–derived precursors. Increasing the alkali equivalent generally increased strength and shrinkage, while PCR replacement generally reduced post–demolding sealed contraction. Potentially expansive products may contribute to this reduction. At 3% PCR, relatively low carbonation depths and non–steady–state chloride migration coefficients were obtained, whereas higher PCR contents could yield higher sulfate corrosion–resistance coefficients under certain conditions. An appropriate PCR dosage can effectively improve strength, shrinkage resistance, and durability, indicating potential for PCR valorization in alkali–activated mortars.
