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Ettore Majorana International Science Series of the wood sample before analysis can lead to unreliable results because of contamination with tissues not typical of the expected normal wood. Guidelines for the selection of wood material are given in the first part of this chapter. The discussion is limited to stem wood.玉米棒子 发表于 2025-3-27 07:00:48
Dynamical Processes in Disordered Systems, formed of about 100 cellulose chains, are embedded in a matrix of hemicelluloses and lignin. Pores in the matrix are small and enable transfer of water, salts, and small organic molecules only. Although the hemicelluloses are at least partly water soluble, they cannot diffuse out of the cell wall d影响带来 发表于 2025-3-27 09:56:16
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G. Careri,A. Giansanti,J. Rupleywith neutral solvents (Hillis 1962; Ekman 1979; Saranpää and Nyberg 1987; Fengel and Wegener 1989; Rowe 1989; Kai 1991; Sjöström 1993). These water-insoluble, lipophilic extractives are also called wood resin. However, although some of the phenolic extractives, mainly occurring in heartwood, can be引导 发表于 2025-3-27 19:55:12
G. Careri,A. Giansanti,J. Rupleyus separation of the components or component groups from each other. Although the details of the structure and composition generally can be obtained only to a limited extent, these direct methods possess definite advantages. For example, a minimum of preparation is required. Often samples can be ana推测 发表于 2025-3-27 22:45:28
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https://doi.org/10.1007/978-3-642-82657-3pulps and are carried over to papermaking operations. This material represents a multitude of different components, which interact with one another and with the pulp fibers, fillers, and process chemicals at the wet end of the paper machine. Along with the trend of minimizing the use of fresh waterDelectable 发表于 2025-3-28 09:36:35
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Institute for Amorphous Studies SeriesThe chemical composition of wood and pulps is briefly reviewed in this chapter, with reference to the relevant analytical problems. The purpose is to give a background to the following chapters, which deal specifically and in more detail with the separation techniques and analytical methods in wood chemistry.