Gradually increase the temperature of the freezer and maintain it
The surface vapor pressure of ice differs greatly at different temperatures. In this temperature range, the natural speed of ice sublimation is faster. Then in a closed container, the frozen lacquer cups are subjected to decompression treatment, and the stability is destructed. Evaporation balance can continuously eliminate moisture and achieve dewatering faster. Freeze-drying is under ultra-low temperature conditions, so that the water volume does not significantly expand and transform into ice crystals. Ice crystals are used to support the heavily corroded lignocellulosic cell wall. When ice crystals sublimate, the water directly enters the atmosphere in gaseous form, which avoids water. The effect of surface tension on cell fibers. In the natural world, the volatilization process of ice consists of two forms. The first is below the freezing point. The surface water molecules rely on the four processes of air flow. At the same time, a water beaker is used as a control. When the moisture in the beaker is fully frozen After that, gradually increase the temperature of the freezer and maintain it within one minute, and start the deceleration pressure treatment. Test the weight of utensils every day. When the weight loss value is lower than that, it can be considered as the end of the drying. Compared with current wood, the dehydrated lacquer ware with fixed type ancient wood has significantly larger extracts, lower cellulose and hemicellulose content, and increased percentage of lignin due to the formation of semi-fibers. The low-molecular-weight substances such as polyxylose polymannose polygalactosaccharides are not very stable to each other, and they are easily immersed in the ground for long-term dissolution and degradation, resulting in increased or enlarged cell wall pores and long-term exposure to groundwater and microbial degradation enzymes. As a result, some cellulose molecules are gradually disappeared. As a result, the wood presents a porous state, the emptiness rate increases greatly, some thin-walled tissues are perforated, and the overall strength of the wood tire is not as great as before. The artifacts of this type of material need to be fixed. Can only be collected.
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