Dimensional stability proves to be an important factor affecting the quality of wooden products. As a sort of crude and thermoplastic resin, shellac excreted by lac insects demonstrates water-repellent and environmental-friendly features. The research impregnated shellac with wood at room temperature and with a vacuum-pressure procedure. Efforts were made to examine how shellac treatment affected the dimensional stability, moisture absorption, chemical structure, thermostability, as well as morphological characteristics of wood. Results indicated that shellac treatment was a type of efficient solution useful in the enhancement of the dimensional stability of wood. Shellac solution had good permeability in the wood, and the weight percentage gain reached 13.01% after impregnation. The swelling coefficients of treated wood in the tangential and radial directions decreased by 20.13% and 24.12%, respectively, indicating that impregnation could improve wood dimensional stability. The moisture absorption of shellac-treated wood was reduced by 38.15% under 20 °C and 65% relative humidity. Moreover, shellac treatment significantly modified wood structure, although there were no drastic changes in the spectra. Specimens for shellac treatment ran across two decomposition peaks at 350 and 390 °C, and specimens in the control group saw one more common derivative thermogravimetric curve when the sharp peak approached 355 °C. After impregnation of shellac into wood, the shellac blocked pits and hardened on the intrinsic layer of the wood for fear of hygroscopicity. The practice was applicable to a variety of wood products, such as buildings, furniture, and landscape architecture.
Linseed oil and shellac are natural, environmentally friendly materials with good water repellency. They were used to impregnate Chinese ash wood at room temperature (20 °C) using a vacuum-pressure procedure (consisting of three cycles of 0.01 MPa for 1.5 h and atmospheric pressure for 1.5 h) to improve the dimensional stability of wood. The effects of the impregnation treatment on wood color changes, dimensional stability, moisture absorption, and morphological characteristics were evaluated. The linseed oil and shellac treatment improved the dimensional stability of wood. Linseed oil and shellac displayed good permeability in Chinese ash wood, with weight gains of 21.7% and 19.0%, respectively, after impregnation. The swelling coefficients of treated wood in the tangential and radial directions decreased by 15 to 22%, indicating that impregnation improved the dimensional stability of wood. Linseed oil and shellac solidified and occluded the pits within the wood interior to prevent moisture absorption. This method can be used to improve the dimensional stability of a variety of wood products, such as buildings, furniture, and landscape architecture.
Under the development of interdisciplinary fusion, user research has been greatly influenced by technology-driven neuroscience and sensory science, in terms of thinking and methodology. The use of technical methods, such as EEG and eye-tracking, has gradually become a research trend and hotspot in this field, in order to explore the deep cognitive states behind users’ objective behaviors. This review outlines the applications of EEG and eye-tracking technology in the field of user research, with the aim of promoting future research and proposing reliable reference indicators and a research scope. It provides important reference information for other researchers in the field. The article summarizes the key reference indicators and research paradigms of EEG and eye-tracking in current user research, focusing on the user research situation in industrial products, digital interfaces and spatial environments. The limitations and research trends in current technological applications are also discussed. The feasibility of experimental equipment in outdoor environments, the long preparation time of EEG experimental equipment, and the accuracy error of physiological signal acquisition are currently existing problems. In the future, research on multi-sensory and behavioral interactions and universal studies of multiple technology fusions will be the next stage of research topics. The measurement of different user differentiation needs can be explored by integrating various physiological measurements such as EEG signals and eye-tracking signals, skin electrical signals, respiration, and heart rate.
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