摘要：
In this study the effect of heat treatment on some physical properties of Douglas fir (Pseudotsuga menziesii) was investigated. Wood specimens were subjected to heat treatment at 160, 180, 200 and 220°C for 1, 2, 3 and 4h. The results show that heat treatment resulted in a darkened color, decreased moisture performance and increased dimensional stability of wood. Compared with untreated wood, equilibrium moisture content (EMC), water absorption (WA) and volume swelling (VS) for treated wood decrease up to 42.63%, 34.93% and 67.47%. The higher the treatment temperature and the longer the treatment time, the lower EMC, WA and VS. The VS of treated specimens has a more significant reduction than EMC and WA when the heat treatment temperature is above 180°C. The visual color changes were more distinct after heat treatment above 180°C. Temperature has a greater influence than time on these properties of specimens.
作者：
LI Xian-jun;LU Ke-yang;LIN Lan-ying;ZHOU Yong-dong;CAI Zhi-yong;...
期刊：
森林生态系统(英文),2010年12(1):9-13 ISSN：2095-6355
通讯作者：
Xian-jun Li
作者机构：
Material Science and Engineering School, Central South University of Forestry and Technology, Changsha, P. R. China;Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing, P. R. China;USDA Forest Products Laboratory, Madison, USA;[LU Ke-yang; LIN Lan-ying; FU Feng; ZHOU Yong-dong] Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China;[LI Xian-jun] Material Science and Engineering School, Central South University of Forestry and Technology, Changsha 410004, China, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China
通讯机构：
[Xian-jun Li] M;Material Science and Engineering School, Central South University of Forestry and Technology, Changsha, P. R. China<&wdkj&>Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing, P. R. China
摘要：
The objective is to evaluate the primary mechanical and physical properties of particleboard made from hammer-milled rice straw particles of six different categories and two types of resins. The results show the performance of straw particleboards is highly dependent upon the straw particle size controlled by the opening size of the perforated plate inside the hammer-mill. The static bending and internal bonding strength of polymeric diphenylmethane diisocyanate (pMDI) resin-bonded boards initially increase then decrease with decreased particle size. The thickness swelling, water absorption, and linear expansion of particleboards decrease with increasing particle size. Compared with pMDI resin-bonded panels, the rice straw particleboard bonded using urea-formaldehyde resin exhibits much poorer performance. The optimized panel properties, obtained when using 4% pMDI and straw particles hammer milled with a 3.18 mm opening perforated plate, exceeded the M-2 specification of American National Standard for Wood Particleboard.
作者机构：
School of Material Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, China;[蔡智勇] USDA Forest Products Laboratory, Madison, 53726-2398, United States;[周永东; 傅峰] Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing, 100091, China;[李贤军] School of Material Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, China, USDA Forest Products Laboratory, Madison, 53726-2398, United States
通讯机构：
[Li, X.-J.] S;School of Material Science and Engineering, Central South University of Forestry and Technology, China
期刊：
2010 4TH INTERNATIONAL CONFERENCE ON BIOINFORMATICS AND BIOMEDICAL ENGINEERING (ICBBE 2010),2010年:1-4 ISSN：2151-7614
通讯作者：
Li, Xianjun
作者机构：
[Liu, Yuan; Yang, Xia; Mou, Qunying; Li, Xianjun; Yan, Yonglin] Cent South Univ Forestry & Technol, Sch Mat Sci & Engn, Changsha, Hunan, Peoples R China.;[Cai, Zhiyong] US Forest Serv, Forest Prod Lab, USDA, Madison, WI USA.
通讯机构：
[Li, Xianjun] C;Cent South Univ Forestry & Technol, Sch Mat Sci & Engn, Changsha, Hunan, Peoples R China.
会议名称：
4th International Conference on Bioinformatics and Biomedical Engineering (iCBBE)
会议时间：
JUN 18-20, 2010
会议地点：
Chengdu, PEOPLES R CHINA
会议主办单位：
[Li, Xianjun;Mou, Qunying;Liu, Yuan;Yan, Yonglin;Yang, Xia] Cent South Univ Forestry & Technol, Sch Mat Sci & Engn, Changsha, Hunan, Peoples R China.^[Cai, Zhiyong] US Forest Serv, Forest Prod Lab, USDA, Madison, WI USA.
会议论文集名称：
International Conference on Bioinformatics and Biomedical Engineering
关键词：
Microwave treatment;Extraction content;Resin;Masson pine
摘要：
The effect of microwave treatment on the petroleum ether extraction content of Masson pine wood was determined. The change in core temperature of samples treated in microwave field was investigated. The results show that the content of petroleum ether extraction of Masson pine can be decreased by 12.95-57.26% by the microwave treatment. The reduction in petroleum ether extraction content (RC) of specimen increases with increasing in microwave radiation power and treatment time. The RC of specimens initially increases then decreases as the initial moisture content changed from about 40-100%. The whole microwave treatment process can be divided into rapid warming-up and constant temperature period, the overflowing of resin onto the wood surface mainly occurs in the constant temperature period. In microwave treatment, the RC of specimens may mainly be due to the resin within resin cavities overflowing onto the wood surface.
摘要：
A theoretical model was developed to better understand the process of microwave explosion treatment of wood cells. The cell expansion and critical conditions concerning pressure and temperature of ray parenchyma cells in Eucalyptus urophylla were simulated during microwave pretreatment. The results indicate that longitudinal and circumferential stresses were generated in the cell walls owing to the internal steam pressure during extensive microwave treatment. The circumferential stress is twice as high as the longitudinal stress. The pressure difference reaches its maximum value of 0.84 MPa when the extension ratio is 1.20 for the longitudinal direction and 1.62 for the circumferential direction. The maximum pressure difference at the theoretical yielding point is the critical pressure difference that can eventually rupture the ray cell. The critical pressure difference decreases with increasing cell radius and decreasing shear modulus in the cell wall. This simulated result provides useful information to modify wood at the level of ray parenchyma cells.
作者机构：
[姜笑梅; 陈志林; 周永东; 傅峰] Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China;[李贤军] School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China
通讯机构：
[Fu, F.] R;Research Institute of Wood Industry, Chinese Academy of Forestry, China
