最新刊期
      期 5 ， 2020

        Research & Development

      • LI Shan-ming,XING Xue-feng,LIN Lan-ying,ZHOU Yong-dong,FU Feng
        Vol. 34, Issue 5, Pages: 1-6(2020) DOI: 10.19455/j.mcgy.20200501
        摘要：Radiata pine（Pinus radiata） wood was treated under high energy density microwave conditions to improve its bending property. The results showed that the coefficient of Pinus radiata wood bendability increased at the beginning of the process, then decreased with the increasing of microwave energy density. Through a proper pretreating process, the excellent bending property of Pinus radiata wood could be obtained. When the microwave energy density increased to a certain value, microscopical cracks appeared in wood, and the bending properties decreased. The optimal microwave pretreatment process was 100 kW（microwave power）, 1.0 m/min（processing speed）; the corresponding energy density of microwave treatment was 31.56 kW·h/m3. For Pinus radiata wood treated under the optimal condition, the maximum coefficient of bendability Kbend was 0.032（corresponding to the coefficient derivative of bendability 1/Kbend value of 31.25）, which was higher than that of the untreated beech, ash wood and elm wood.  
          
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        发布时间：2021-01-27
      • QIU Hong-yun,LONG Ling,LIU Ru,XU Jian-feng,LI Xiao-yan
        Vol. 34, Issue 5, Pages: 7-12(2020) DOI: 10.19455/j.mcgy.20200502
        摘要：A series of experiments were conducted to explore the effect of various concentrations of Fe2（SO4）3 solution on the color change of oak floor; the color stability of treated wood during the accelerated aging process of UV and high temperature and humidity was investigated. The results showed that the oak became darkened, greening and bluing with the increasing concentration of Fe2（SO4）3. After the concentration value was higher than 6%, the surface color did not further change. After 96 hours of the UV aging treatment, the surface color of all samples tended to be darkened, reddening and yellowing; the intensity of color change of samples under the high temperature and humidity conditions was different, and inclining to be darker, more reddish and blueish. The samples treated with 8% concentration of Fe2（SO4）3 solution presented the best color stability. The Fe2（SO4）3 treatment contributed to darken the surface of the oak. The samples had better color stability and different shades of colors after the UV coating. It was suggested that further studies on optimizing the Fe2（SO4）3 treatment need to be carried out to form a chemical coloration method for wood surfaces with stable and attractive color properties.  
        关键词：European oak;color;solution of ferric sulphate;accelerated aging   
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      • TANG Ling-xie,QIAN Jing,HE Zheng-bin,YI Song-lin
        Vol. 34, Issue 5, Pages: 13-16(2020) DOI: 10.19455/j.mcgy.20200503
        摘要：To improve the drying rate and drying quality of Samanea saman Merr., the wood samples were pretreated under the conditions of ultrasonic frequency of 25 kHz, power of 340 W, and time of 30, 60, and 90 minutes. The effects of ultrasonic pretreatment on relative crystallinity, drying rate and dimensional stability of Samanea saman Merr. were explored. The results showed that drying speed and dimensional stability were improved along with the increasing pretreatment time; the ultrasonic pretreatment increased its relative crystallinity. Considering the drying rate and energy consumption, the optimal ultrasonic pretreatment time of Samanea saman Merr. under this test condition was 60 minutes.  
        关键词：Samanea saman Merr.;ultrasonic pretreatment;crystallinity;drying rate;dimensional stability   
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      • DOU Qing-qing,CHEN Long,ZHOU Yong-dong,NI Yue-ping,NI Yue-zhong
        Vol. 34, Issue 5, Pages: 17-20(2020) DOI: 10.19455/j.mcgy.20200504
        摘要：The surface decoration of Compressed Poplar can be adorned through direct printing technology. The study was conducted on improving the process of adhesive primer and the process of white primer covering wood grain to elevate the reduction of adhesive force level during the printing process. The results showed that the combined technique of waterborne primer and UV adhesive primer, and applying a UV tough primer prior to covering wood grain with white primer can ensure the adhesion level is not reduced. The adhesion force reached the 2 nd grade or above of LY/T 1986—2011"Printed wooden flooring" in accordance with National standard GB/T 4893.4—2013 " Test of surface coatings of furniture-part 4: Determination of adhesion-Cross cut".  
        关键词：compressed Poplar;interface adhesive force;wood grain covering;paint adhesion;waterborne primer;UV adhesive primer;UV tough primer   
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      • GU Shui-xiang,ZHOU Zhuo-rong,DAI Xue-feng,GAO Shui-chang,ZHAO Jian-zhong,PANG Xiao-ren
        Vol. 34, Issue 5, Pages: 21-24(2020) DOI: 10.19455/j.mcgy.20200505
        摘要：Surface-decorative blockboard with paper impregnated thermosetting resins is a kind of decorative wood-based pnales rising in China market in recent years. To improve the flame-retardant performance, the authors developed a special flame-retardant adhesive. The weight ratio of adhesive and flame retardant, and the coating amount were investigated. Results showed that by applying the flame retardant adhesive twice, the water resistance and surface bonding strength of the surface-decorative blockboard met the specifications of the national standard GB/T 34722—2017; the formaldehyde emission value met the requirements of the enterprise standard Q/YFL 0030—2018; and the flame retardancy property met the B1-C level requirements of GB/T 8624—2012.  
        关键词：flame retardant;surface-decorative blockboard with paper impregnated thermosetting resins;flame retardant adhesive;flame retardancy   
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      • ZHANG Feng,CHEN Hao-sheng,ZHANG Bo,DONG Wei-hang,GUO Xiao-lei
        Vol. 34, Issue 5, Pages: 25-29(2020) DOI: 10.19455/j.mcgy.20200506
        摘要：In order to improve the automation level of wooden door leaf processing, according to the characteristics of the side of the wooden door leaf and the requirements of the paint finishing process, a UV paint vertical roller coating machine for the side of the wooden door leaf was designed and developed. The structure and function of the vertical roller coating machine were emphatically introduced. The equipment could complete the side sanding, chamfer milling, vertical roller coating, and paint drying and curing. The adhesive force of varnish met national level 1 requirement in GB/T 4893.4—20 l3 Physical and chemical properties test of paint film on furniture surface-Part 4 Determination of adhesion by cross-cutting.  
        关键词：wood door leaf;vertical roller coating;structural design   
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      • YANG Xiao-meng,ZHANG Xiu-biao,HUANG Ai-yue,FEI Ben-hua,LIU Huan-rong
        Vol. 34, Issue 5, Pages: 30-33(2020) DOI: 10.19455/j.mcgy.20200507
        摘要：Bamboo flattened board made with groove and without groove processing methods were studied. A comparative study was mainly conducted on the dimensional size,mechanical and physical properties and micro characteristics. Results indicated that the density, modulus of rupture, shear strength and modulus of elasticity of bamboo flattened board made without groove were higher than that made with grooves. Warpage of both flattened boards were positively correlated with the board thickness. However, warpage of non-groove flattened board was lower than the other. The better physical and mechanical properties of non-groove flattened board were related to the fact that the bamboo cells are not damaged and only partially compressed during the preparation process, thereby retaining the original structure and performance of bamboo.  
        关键词：flatten bamboo board;grooves;manufacture procedure;physical and mechanical properties   
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        发布时间：2021-01-27
      • ZHU Li-ming,ZOU Xian-wu,LYU Bin,LI Bo-tao,FU Yue-jin,YANG Fan
        Vol. 34, Issue 5, Pages: 34-39(2020) DOI: 10.19455/j.mcgy.20200508
        摘要：Based on the principles of evaluation of formaldehyde content and release amount from wood-based panels, this paper systematically summarizes the previous researches on the correlation of formaldehyde detection methods on wood-based panels. Through the analysis of the formaldehyde release process from the wood-based panels, the functional relationship between the formaldehyde content of the panel and the formaldehyde concentration in the air environment was theoretically derived. According to the standard test parameters and the formaldehyde emission law of the panel, the function relationship is simplified, and the linear calculation equation was obtained from the climate chamber method, the perforation extraction method and the desiccator method, which provides theoretical support for establishing the correlation of formaldehyde detection methods for wood-based boards, and theoretical basis for the development and application of linear calculation equations.  
        关键词：wood-based panel;formaldehyde;test method;correlation   
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        发布时间：2021-01-27

        Discussion & Suggestion

      • YU Hua-qiang,AN Xin,ZHAO You-ke,LI Xiao-ling
        Vol. 34, Issue 5, Pages: 40-43(2020) DOI: 10.19455/j.mcgy.20200509
        摘要：In order to provide evidences for revising the national standard of GB/T 1941—2009 Method of testing in hardness of wood, the authors analyzed the advantages and disadvantages of various wood hardness test methods such as the Brinell hardness method, the Janka hardness method, the hardness modulus method, surface hardness method, and the Monnin hardness method, etc. The standards on test methods of wood hardness in China and abroad were compared. Among these test methods, Janka hardness is the most widely adopted by ISO and many countries because it is very simple, accurate and efficient. GB/T 1941—2009 does not specify a hardness test method for green wood, therefore it is recommended to add in. The hardness modulus test method is proposed for the purpose of measuring the wood-based panel with a thickness greater than 3 mm and wood susceptible to crack.  
        关键词：wood;wood-based panels;hardness;standard;test method;moisture content   
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      • ZHENG Hong-lian,LIU Xu-dong,GU Qiang,DENG Chao
        Vol. 34, Issue 5, Pages: 44-48(2020) DOI: 10.19455/j.mcgy.20200510
        摘要：The objective is to compare the Chinese standard and ISO standards on plywood. The differences between Chinese and ISO standards in quality specifications and test methods are identified and analyzed. It is expected to provide references for plywood production, trade and standard revision.  
        关键词：plywood;blockboard;decorative veneered plywood;national standard;ISO standard   
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      • CHE Yan-ping
        Vol. 34, Issue 5, Pages: 49-53(2020) DOI: 10.19455/j.mcgy.20200511
        摘要：The amounts of formaldehyde and volatile organic compounds released from eight selected panel furniture samples were tested by using the environmental chamber method. The predicted concentration was calculated based on simulated conditions（room area of 12 m2, room height of 2.5 m, panel furniture area of 20 m2, ventilation rate of 0.6 times/h）. The result of predicted concentration was compared to the exposure threshold of Chronic Reference Exposure Levels（CREL）. Recommendations were made regarding to the formaldehyde and volatile organic compounds of the panel furniture.  
        关键词：panel furniture;formaldehyde;volatile organic compounds（VOCs）;emissions;exposure threshold   
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        Practical Techniques

      • WANG Rui,WANG Xue-yu,JIA Ru,GAN Jia-bing,REN Hai-qing,WANG Yu-rong
        Vol. 34, Issue 5, Pages: 54-58(2020) DOI: 10.19455/j.mcgy.20200512
        摘要：Partial least squares method（PLS） was used to establish a method to rapidly predict the air-dry density of Quercus variabilis by near infrared（NIR） spectroscopy. The wood densities of 131 samples from the different radial positions in four trees were determined by referring to GB/T 1933—2009 "Method for determination of wood density", and their NIR spectra were collected. The results showed the effect of model based on NIR spectra taken from the transverse surface was the best. Multiple modeling sample sets were selected by gradient method and multiple PLS models were established. The correlation coefficients of calibration and prediction models were both greater than 0.9. The research showed that it was feasible to predict the wood air-dry density of Quercus variabilis by NIR spectroscopy.  
        关键词：Quercus variabilis;wood density;near infrared spectroscopy   
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      • YOU Yu-guang,ZHANG Ke-xin,YUE Xiao-quan
        Vol. 34, Issue 5, Pages: 59-63(2020) DOI: 10.19455/j.mcgy.20200513
        摘要：By applying the principle of the MATLAB digital imaging technique, the images of surface defects on wood arch bridge components were enhanced, and the internal stress wave images were segregated and the defect areas were calculated. The effects of textural feature of defective pillars on the stress wave images were evaluated. The results showed that MATLAB software performed effectively on detecting the surface defects and analyzing internal stress wave images of the wood members. Based on area analysis of segregated areas and textural feature calculations of stress wave images, the pixel area and entropy value are proposed to be used as primary evaluation indexes for stress wave image analysis.  
        关键词：MATLAB software;wood component defects;image processing   
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      • SUN Hong-jie,MENG Guang-yao,HUANG Ju-xin,GUO Bin,WANG Zhen-hua
        Vol. 34, Issue 5, Pages: 64-68(2020) DOI: 10.19455/j.mcgy.20200514
        摘要：Due to the variation of log diameters at the operation of the conveyor, it is not uncommon to cause abnormal operation of the dial device so that the logs were blocked from entering the next stage. In response to the above issue, four solutions were proposed. The statics of the horizontal "string" dial structure and the "mouth" dial structure were analyzed using related software, and the results showed that the horizontal "string" dial structure scheme met the requirements. It was suggested that various factors need to be considered comprehensively, and the "electric-snail" control dial structure and the "reduction-curve" control dial structure were selected according to actual requirements.  
        关键词：conveyor;dial structure;optimal design;log diameter;finite element analysis   
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