最新刊期
期 6 ， 2021
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摘要：Wood modification is an efficient approach to improve wood properties and function wood. The main research topics of wood modification include the types of modifiers, optimization of the modification process, and investigation of modifying mechanism, which all depend on the advanced characterization and analysis techniques. Imaging spectrometry which is combining a spectrometer with an optical microscope, provides insights of chemical compositions in context with microstructure at the micrometer level, particularly the micro-mechanical properties. It has become an important tool for wood characterization. In this review, the application of imaging spectrometry techniques on wood modification are summarized, mainly including infrared microspectroscopy, Raman microspectroscopy, and confocal laser scanning microscopy. Additionally, the existing problems of the imaging spectrometry techniques used for wood modification are presented, as well as the potential development are outlooked.关键词：wood modification;microspectroscopy;infrared microspectroscopy;raman microspectroscopy;confocal laser scanning microscopy;application progress- 229
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发布时间：2021-12-05 -
Suitability Testing Technology of Invisible Damage in Wooden Components of Ancient Timber Structures
摘要：The ancient Chinese timber structures have rich variety of styles. It is tedious to form a set of nondestructive testing methods for every type of components, therefore, the authors proposed a simplified method, which is based on the component shapes (circle, square), positions (buried-wall, exposed), and compositions (single wood, jointed member) of ancient wooden structures. This method can be generalized into eight combination types, such as circular components and quadrate based on their shapes, embedded components and open components based on their positions, single components and split components based on their structures. A nondestructive testing technology system for wooden components was developed through a suitability testing research on the eight combination components. The rapid identification and reliable characterization of invisible damage were achieved.关键词：ancient timber structure;wooden components;invisible damage;suitability testing;nondestructive testing- 95
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发布时间：2021-12-05 -
摘要：In the modern logistics system, the pallets have become an important equipment in the operation process of loading, unloading, storage, and transportation. This article introduced a green environment friendly product — molded wood-particle pallets, which had great potentials in the industry. It was expounded of the current industry status and the research progress of manufacturing process and product standards of domestic and foreign molded wood-particle pallets industry. The prospects of the development of molded wood-particle pallets industry were proposed.关键词：molded wood-particle pallets;industry status;research progress;development trends- 58
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发布时间：2021-12-05
REVIEWS
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摘要：In the era of transferring from traditional industry to intelligent manufacturing, this paper analyzes the current situation of product design and data management of customized furnishing products, expounds the advantages and significance of parametric three-dimension (3D) design, and introduces a method of applying parametric 3D design in intelligent manufacturing. In this study solid wooden doors were custom manufactured based on the analysis of serialization, standardization and modularization. The parametric 3D design was conducted by using the constraint block of TopSolid software in setting up the part model bases and product family template models. Further, according to the topological relationship of product assembly structure, parametric 3D design was adjusted quickly and efficiently for individual customer requirements. The parametric 3D software can output BOM, NC code, and other information, which are conducive to promoting intelligent manufacturing integrating design, manufacturing and production management.关键词：custom intelligent manufacturing of interior furnishings;Parameterization;three-dimension design;TopSolid- 68
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发布时间：2021-12-05
SPECIAL REPORTS I
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摘要：In order to investigate the effect of methanol extraction on cell walls pore structure of Eucalyptus obliqua heartwood, the heartwood powder was extracted with methanol. The cell wall pore structures of controlled and extracted samples were evaluated by the N2, CO2 sorption and pycnometer methods, respectively. The results indicated that Eucalyptus obliqua heartwood extractives mainly existed in the micropores of cell walls in the range of 0.4~0.7 nm. The existence of extractives in the cell walls of Eucalyptus obliqua heartwood led smaller pore volume and porosity, which possibly was one of the reasons for the slow drying speed of Eucalyptus obliqua heartwood.关键词：methanol extraction;Eucalyptus obliqua heartwood;cell wall pore structure;gas isotherm sorption method;pycnometer method- 53
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发布时间：2021-12-05 -
摘要：In order to improve efficiency, accuracy and commonization, the traditional LeNet-5 model was modified for detecting wood surface defects by increasing the number of convolutional layers and the pooling layers to 4 so that the network depth was increased. The batch normalization algorithm was used to solve internal co-vitiate shift displacement over-fitting problem. Leaky Relu function was used as the activation function, then sparse categorical cross entropy was added as the loss function, as well as Adam was used as the optimizer to enhance the network model. The comparison test was carried out on the samples of Pinus radiata with and without classical defects(knots and cracks). The results showed that the modified LeNet-5 model performed best comparing with VGG19, AlexNet and ResNet-50 classic models. The accuracy rate was 99.87%; the verification set was 99.43%; the operation time was reduced, therefore the accuracy and efficiency of detecting wood surface defects were improved.关键词：wood defect detection;modified LeNet-5 model;Deep learning;convolution neural network- 50
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发布时间：2021-12-05 -
摘要：In the study, a green and environment-friendly melamine-urea-glyoxal (MUG) resin was synthesized by mixing melamine, urea, glyoxal, and additive for upgrading low-quality rubberwood. Wood/MUG samples were prepared with six different MUG resin concentrations (5%, 15%, 25%, 35%, 45%, and 55%) into the wood matrix, and then heated and polymerized to form a solid and hydrophobic resin in the wood. The physical and mechanical properties of the modified woods were evaluated. The results showed that as the resin concentration increasing, the weight percent gain and density of modified wood samples increased, water uptake and leachability decreased, and the anti-swelling efficiency increased at first and then decreased. SEM-EDX analysis showed that the MUG resin was widely distributed in the cell lumens and cell walls. Modulus of rupture (MOR) and modulus of elasticity of 25% MUG resin treated wood samples were increased by 19.9% and 14.3%, respectively, comparing with untreated control samples. Compression strength parallel to the grain of the treated wood samples was increased by 19.2% than that of control samples. In conclusion, MUG resin was successfully deposited on the cell walls of rubberwood, and the water uptake of treated wood samples was decreased, and the physical and mechanical properties of rubberwood were improved.关键词：melamine-urea-glyoxal resin;rubberwood modification;microstructure;physical and mechanical properties- 80
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发布时间：2021-12-05 -
摘要：The transverse stiffness was an important factor affecting the stability of circular saw blade during cutting process. In this paper, four typical structures of circular saw blades were taken as the research objects, and their mechanical models were established by nonlinear finite element method. The variation of transverse stiffness of circular saw blades were studied under the centrifugal force alone, temperature field alone, and under both conditions respectively. The results showed that transverse stiffness of circular saw blade decreased with increasing sawing temperature while the centrifugal force strengthened the transverse stiffness of circular saw blade. The structure of circular saw blade has an influence on the change of its transverse stiffness with the temperature load.关键词：circular saw blade;temperature;centrifugal load;stiffness;finite element method- 27
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发布时间：2021-12-05 -
摘要：Based on the formaldehyde emission data of laminate flooring in a 1 m3 radiant heating simulation chamber, a formaldehyde emission regression model was proposed by linear and nonlinear regression methods according to the relationships among temperature, relative humidity, bearing capacity, time, and the formaldehyde emission concentration. Verification results showed that the model had high calculation accuracy and effectively predicted formaldehyde emissions from laminate floorings under different heating environments.关键词：Laminate flooring;ground heating systems;formaldehyde emission;regression model- 88
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发布时间：2021-12-05 -
摘要：The cutting of wood-based panels is rectangular cutting under the restrained guillotine. It is solved by a local enumeration through a greedy strategy. The relationship among the utilization rate of the raw material board, the computing time, and the cutting sequence of the work pieces is analyzed. A greedy cutting algorithm is proposed. The experimental results show that the cutting sequence of the workpieces has little effect on the utilization rate of the raw board, and the utilization rate of the raw board changes within 0.05%, but the calculation time increases exponentially with the expansion of the enumeration space. Comparing with the literature, the algorithm can improve the raw material board utilization rate by 1.3%; the remaining material quantity is reduced by 30.8%.关键词：wood-based panel cutting;greedy algorithm;cutting of enumeration;detection of guillotine- 28
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发布时间：2021-12-05
RESEARCH PAPERS
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摘要：Single-factor experiment was conducted for investigating a rapid bleaching process for wood veneer of Taxodium hybrid "Zhongshanshan 302". Hydrogen peroxide and ammonium bicarbonate were used as chemical bleaching agents; the degree of color difference and whiteness difference of the bleached veneer were served as evaluation indicators. The results showed that H2O2 concentration and treatment temperature had less effect on bleaching performance. However, NH4HCO3 concentration of 25% had a greater effect on bleaching process. Combining with range and variance analysis, the optimum rapidly bleaching process were selected as follows: the ratio of hydrogen peroxide (mass fraction was 15%) to ammonium bicarbonate (mass fraction was 15%) was 1∶1; the bleaching temperature was 70 ℃; and the treatment duration was 3 min. Under this situation, the value of color difference and whiteness difference of the bleached veneer were 19.6 and 15.1%, respectively. The results proved that the formulation of H2O2 and NH4HCO3 was suitably for bleaching Taxodium hybrid "Zhongshanshan 302" veneer and provided a theoretical basis for rapidly bleaching process for industrial applications.关键词：veneer of Taxodium hybrid "Zhongshanshan 302";bleaching process;color difference;whiteness difference- 33
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发布时间：2021-12-05 -
摘要：Three types of adhesives were used to develop molded wood-particle pallets with different resin contents. The performance test showed that the integrated property of MDI molded wood-particle pallets was the best, and the formaldehyde emission of the pallets was almost undetectable, therefore it was formaldehyde-free level. The molded wood-particle pallets made with phenolic resin performed secondly. The overall performance of molded wood-particle pallets made with urea-formaldehyde resin was relatively poor. The MDI molded wood-particle pallets have a competitive advantage in the transportation and storage of goods in industries such as medicine, electronics, food, etc. and/or in humid environments. The molded wood-particle pallets made with phenolic resin glue and urea-formaldehyde resin glue are mostly used in general cargo transportation, chemical, energy and other industries.关键词：molded wood-particle pallets;adhesive;resin content;physical and chemical properties- 37
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发布时间：2021-12-05
RESEARCH BRIEFING
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Creating Green Wood-Based Panels Industry to Meet the CO2 Emission Peak and Carbon Neutrality Target
摘要：Creating green factory is one of the important strategies to achieve the double-carbon goals and is a complex system. Its evaluation index includes CO2 emission of per unit products, carbon footprint, environmental pollution and other indicators which closely relate to CO2 emission peak and carbon neutrality. Based on the policies and standards of green factory, this article proposed the suggestions for creating green factory in wood-based panels industry, so as to guide the wood-based panels industry to meet the requirements of GB/T 36132—2018 General Principles for Assessment of Green Factory, and to promote the green development of wood-based panels industry.关键词：CO2 Emission Peak and Carbon Neutrality Target;green factory manufacturing wood-based panels;energy consumption;carbon emissions;carbon footprint- 118
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发布时间：2021-12-05 -
摘要：The Hongmu imports trade in China has the distinct characteristics, influenced simultaneously by the international trade policy and special relations between Chinese market supplies and demands. The governance and protection policy of international organizations on Hongmu trade is impacting the operations of Chinese Hongmu industry. Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and the red list of the International Union for the Conservation of Natural Resources (IUCN) have enhanced regulation rules on Hongmu timber species. Based on the custom statistics in the past six years, this paper expounded volumes, prices, species of imported Hongmu, and the structure and characteristics of imported resources. The growing trend of Hongmu trade in the future was predicted. Finally, based on the international policy and trade situation, the sustainable development suggestions for Chinese Hongmu industry were put forward.关键词：Hongmu;Appendix of Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES);IUCN Red List of threatened species;imports trade- 55
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发布时间：2021-12-05
DISCUSSION ＆SUGGESTION
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摘要：This article briefly introduced the development status of wood-plastic composite flooring and analyzed the relevant standards of wood-plastic composite products. The principle indexes of the new-edition standard GB/T 24508—2020 were described, including the minimum concentrated load, modulus of rapture (MOR) and modulus of elasticity (MOE), the coefficient of linear thermal expansion, the phthalate content, formaldehyde emission, and the release rate of total volatile organic compounds (TVOC). These information provide a proper guidance for the application of the standard.关键词：wood-plastic composite flooring;minimum concentrated load;modulus of rapture (MOR);modulus of elasticity (MOE);coefficient of linear thermal expansion;formaldehyde emission;total volatile organic compounds (TVOC)- 85
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发布时间：2021-12-05
DISCUSSION ON STANDARDS
- Address：Box 29，Research Institute of Wood Industry, No. 1, Dongxiaofu, Haidian District, Beijing Postal code：100091
- Tel：010-62889419 Email：mckx@caf.ac.cn
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