Hexi painting (和玺彩画) was historically documented as the most sophisticated decorative art representing the highest levels of technological knowledge and skills for decorating the Chinese Qing (1644-1911 AD) imperial architecture. However, the technological complexity of Hexi painting has barely been scientifically investigated. This article presents a technical case study that aimed to promote a better understanding of (inorganic) materials used in, and the painting/decorating procedure of, Hexi painting. Microscopic examination, compositional analysis, and phase/fiber identification were applied on fragments of golden-dragon Hexi painting (金龙和玺彩画), the most prestigious form of Hexi painting, which were sampled from Xitian Fanjing (西天梵境) in Beihai Park (Beijing, China). The results suggest that neither the kinds of used (inorganic) materials nor the painting/decorating process is exclusively restricted to Hexi painting and distinguishes it from other contemporaneous decorative forms. It is the combination of material use and the painting/decorating procedure that seems to make Hexi painting special. Further studies are needed to investigate the use of organic materials in Hexi painting to expand our current understanding.
In this study, a theoretical model has been constructed to address the optimization of matching layers for tone burst excitation underwater acoustic transducers and to investigate the functional mechanism change of matching layers. Single, double, and triple matching layers are attached to piezoelectric composite plates, and tone burst signals with a different number of burst-cycles are applied. Acoustic pressure function ( Sp) and acoustic pressure transient response (PTR) are compared among these transducers. The results demonstrated that when the cycle number M ≤ 2, more matching layers lead to shorter ringdown with similar PTR amplitude. Since the objective is for better axial resolution, three matching layers have noticeable advantage, whereas for the case of M > 5, far detection distance is the main objective, and more matching layers caused the decrease in PTR amplitude. Besides, matching layers become part of the resonance structure; they do not serve as a transmission medium anymore. Therefore, the transducer with single matching is optimal for the long tone burst excitation. For the case of 2–5 cycle excitation, one may use double matching layers, which has a balance between the transmitting voltage response amplitude and bandwidth. With the increase in M, the role of matching layers changes from a bridging transmission medium to amplifying vibration velocity and introducing additional vibration modes to broaden the bandwidth.
Microstructure, chemical composition, physical property and high temperature process of furnace materials from Shuiquangou site were analyzed in order to promote an exploratory scientific study on cast iron smelting furnace materials in ancient China. The results showed that raw materials were locally collected and gone through a screened process; there were at least two productions of furnace lining which used in different parts of the furnace. Furnace materials can provide enough Na2O, Al2O3, and SiO2 into slags. The refractoriness of them were about 1 200-1 300°C, and the smelting temperature was among 1 300-1 500°C.KEY WORDS: furnace material; furnace lining; blast furnace; cast iron; refractory material; Shuiquangou site.
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