节点文献
四川两产地桢楠木材构造及其性能研究
Cellular Structures and Properties of Phoebe Zhennan Wood in Sichuan Province, China
【作者】 刘敏;
【作者基本信息】 四川农业大学 , 林业硕士(专业学位), 2016, 硕士
【摘要】 本文选择樟科楠属楠木(桢楠Phoebe zhennan S.Lee)为主要研究对象,选择四川省雅安市芦山县与成都市新津县两个主产地的桢楠树干为试材,研究四川芦山、新津两主产地桢楠木材的细胞构造与性能,分析对比两产地的桢楠在木材构造及其材性方面的差异。选择四川省雅安雨城区的金凤寺桢楠活树新料与雅安芦山桢楠阴沉料为试材,研究四川桢楠新料与阴沉料的细胞构造与性能,分析对比了两种类型的桢楠木材在导管和木纤维的构造特征参数方面的差异,同时将桢楠阴沉料、芦山和新津产地的桢楠木材在密度、干缩湿胀、导热系数和力学性能等方面对比研究。通过手持式显微镜、光学显微镜与电子扫描显微镜分别拍摄对比不同产地与不同类型的桢楠木材的宏观特征与微观特征;通过切片法在光学显微镜下测定了单位面积管孔个数、管孔的长度、宽度和腔径,通过离析法在光学显微镜下测定了导管长度、木纤维的长度、宽度和腔径,并分别推算出管孔与木纤维的长宽比、壁腔比、腔径比,从髓心至边材分组编号研究其径向变异;按照相关国家标准测定不同产地与不同类型的桢楠木材的全干密度、气干密度、基本密度、干缩系数等木材物理性质;通过TC3000型导热系数仪测定不同桢楠试材的导热系数;通过万能力学试验机测定不同桢楠木材的顺纹抗压强度、抗弯强度和硬度等力学强度。结果表明:(1)宏观上芦山桢楠木材颜色为黄褐色带绿,木材表面光泽较弱,带药香,而新津桢楠木材颜色为深褐色带绿,木材表面光泽较强,带甜香;桢楠活树新料木材颜色为浅黄色,木材表面光泽较弱,带清香,而桢楠阴沉料的木材颜色为墨绿色,木材表面光泽较强,带药香。(2)微观上芦山桢楠、桢楠活树新料与桢楠阴沉料均为散孔材,新津桢楠为散孔材至半散孔材,导管横切面均为圆形或半卵圆形,管间纹孔互列式,射线组织为异型II型或异型Ⅲ型。(3)芦山桢楠与新津桢楠树龄接近,属于幼龄材,生长状况不稳定,故导管各参数与木纤维各参数均随树龄的增加呈“波动”的变异模式;而桢楠活树新料与桢楠阴沉料属于百年成材,生长较为稳定,但由于桢楠阴沉料常年埋藏地下,受外界影响较大,导管、木纤维形态发生部分变化并趋于一致,故桢楠阴沉料导管各参数与木纤维各参数随树龄的增加呈“波动”的幅度小于桢楠活树新料。(4)芦山桢楠木材的气干密度0.552g/cm3,基本密度0.464 g/cm3,体积干缩系数0.095%;新津桢楠木材的气干密度0.579/cm3,基本密度0.489/cm3,体积干缩系数0.107%;桢楠阴沉料木材的气干密度0.531g,/cm3,基本密度0.435/cm3,体积干缩系数0.444%;桢楠阴沉料的密度最小,但体积干缩系数远大于芦山桢楠与新津桢楠木材,桢楠阴沉料干燥后更容易发生开裂和翘曲。(5)芦山桢楠木材横切面、径切面、弦切面的导热系数分别为0.210W/m*K、0.161 W/m*K、0.183 W/m*K;新津桢楠木材横切面、径切面、弦切面的导热系数分别为0.221 W/m*K、0.153 W/m*K、0.190 W/m*K;桢楠阴沉料横切面、径切面、弦切面的导热系数分别为0.187 W/m*K、0.178 W/m*、0.181 W/m*K。芦山桢楠和新津桢楠木材的各向导热系数相近,两者横切面与弦切面的导热系数均大于桢楠阴沉料,径切面的导热系数小于桢楠阴沉料,三者各向导热系数均呈现出横切面>弦切面>径切面。(6)芦山桢楠木材试样顺纹抗压强度34.8MPa,抗弯强度64.5MPa,端面硬度4495.3N;新津桢楠木材试样顺纹抗压强度36.2 MPa,抗弯强度67 MPa,端面硬度4580.4N;桢楠阴沉料试样抗压强度31.4 MPa,抗弯强度62.6 MPa,端面硬度3103.5N。新津桢楠木材试样的力学性能最优。
【Abstract】 In this study, we analyzed wood from Phoebe zhennan (family Lauraceae) to identify its particular characteristics and properties. Samples were obtained from P. zhennan growing in Lushan County (Ya’an) and Xinjin County (Chengdu) in Sichuan province. We examined the macrostructure and microstructure of P. zhennan wood, and screened for differences in structural parameters such as density, hygroexpansion, thermal conductivity andmechanical property. Samples were obtained from living tree new material from P. zhennan growing in Jinfeng Temple (Ya’an) and P. zhennan ancient buried wood (Ya’an) in Sichuan province. We examined the macrostructure and microstructure of P. zhennan wood.At the same time we compare these samples were obtained from P. zhennan growing in Lushan County, Xinjin County and ancient buried wood in terms of density, hygroexpansion, thermal conductivity andmechanical property.Through the handheld microscope, optical microscope and scanning electron microscope were taken contrast in different regions and different types of P. zhennan macrostructure and microstructure.The slice method under optical microscope were measured per unit area of pipe hole number and tube hole length, width and lumen diameter, the segregation process under the optical microscope determination of the pipe length, and wood fiber length, width and lumen diameter.The ratio of length to width, ratio of wall to cavity and cavity diameter of the pipe hole and the wood fiber were calculated. And we study on the radial variation from heartwood to sapwood packet number.According to the relevant national standards, the physical properties of wood such as dry density, air-dry density, basic density, dry shrinkage coefficient and so on were measured.The thermal conductivity of wood was measured by TC3000 type thermal conductivity meter.Mechanical strength, such as compressive strength, bending strength and hardness of wood, were studied by universal mechanical testing machine. The results showed that:(1) At the macroscopic level, P. zhennan wood from Lushan was yellowish brown, tinged with green, wood surface gloss was weak and had a herbal fragrance; P. zhennan wood from Xinjin was dark brown, tinged with green, wood surface gloss strong and had a sweet fragrance. P. zhennan wood from Jinfeng Temple was pale yellow, wood surface gloss was weak and had a refreshing fragrance; P. zhennan ancient buried wood was blackish green, wood surface gloss strong and had a medicine fragrance.(2)At the microscopic level, P. zhennan wood from Lushan, P. zhennan wood from Jinfeng Temple and P. zhennan ancient buried wood were diffuse-porous, while that from Xinjin was diffuse-porous to semi-diffuse-porous. Cross section of catheter was round or oval;intervessel pitting alternately tissues were type II or type III heterogeneous.(3)P. zhennan wood from Lushan and P. zhennan wood from Xinjin age closed, belonging to the juvenile wood, the growth status was not stable, so parameters of the catheter and wood fiber parameters were with the age increased showed a "wave" variation pattern;P. zhennan wood from Jinfeng Temple and P. zhennan ancient buried wood belonged to the hundred years of timber, relatively stable growth.Because of P. zhennan ancient buried wood undergroundfor many years, affected by the outside world.The shape of the catheter and the wood fiber were changed and tended to be consistent.Therefore, the parameter ofcatheter and wood fiber with the increase of age showed a "wave", and was smaller than the P. zhennan wood from Jinfeng Temple.(4)P. zhennan wood from Lushan air dry density, basic density, volume shrinkage coefficient were 0.552g/cm3,0.464 g/cm3,0.095%; P. zhennan wood from Xinjin air dry density, basic density, volume shrinkage coefficient respectively were 0.579g/cm3,0.489 g/cm3,0.107%; P. zhennan ancient buried wood air dry density, basic density, volume shrinkage coefficient respectively were 0.531 g/cm3,0.435 g/cm3,0.444%.The P. zhennan ancient buried wood density was the smallest, but the volume shrinkage coefficient was far greater than the P. zhennan wood from Lushan and P. zhennan wood from Xinjin.The P. zhennan ancient buried wood was more prone to cracking and warping.(5)P. zhennan wood from Lushan in cross section, radial section and tangential section of the heat conduction coefficient were 0.210W/m*K,0.161 W/m*K,0.183 W/m*K. P. zhennan wood from Xinjin in cross section, radial section and tangential section of the heat conduction coefficient were 0.221 W/m*K、0.153 W/m*K、0.190 W/m*K.The P. zhennan ancient buried wood in cross section, radial section and tangential section of the heat conduction coefficient wereO.187 W/m*K、0.178 W/m*K、0.181 W/m*K.The thermal conductivities of wood from Lushan and Xinjin were similar, The cross section and tangential section of the heat conduction coefficient from Lushan and Xinjin were larger than the P. zhennan ancient buried wood.They were in the order:cross section> tangential section> radial section.(6) P. zhennan wood from Lushan incompressive strength,bending strength and surface hardness were 34.8MPa,64.5 MPa,4495.3 N. P. zhennan wood from Xinjin incompressive strength,bending strength and surface hardness were36.2 MPa,67 MPa,4580.4N.The P. zhennan ancient buried wood incompressive strength,bending strength and surface hardness were 31.4 MPa,62.6 MPa,3103.5 N.The mechanical properties of P. zhennan wood from Xinjin were the best.
【Key words】 Phoebe zhennan; Cellular structure; Physical properties; Thermal conductivity; mechanical property;
- 【网络出版投稿人】 四川农业大学 【网络出版年期】2017年 03期
- 【分类号】S781.8
- 【被引频次】11
- 【下载频次】290