Effect of compression on hydroscopicity of extracted Chinese fir heartwood

In order to clarify the effects of extraction and compression on the hydroscopicity of wood, Chinese fir （Cunninghamia lanceolata Hook.） heartwood samples with or without extraction were radially or tangentially compressed under water-saturated condition at room temperature. Warm water and 1% sodium hydroxide were used as different solutions for extraction. Water absorption capacity and moisture adsorption isotherms of the compressed samples were then tested. The fractal dimension of internal wood surfaces （Dfs） was calculated based on adsorption isotherms by FHH equation. Results showed that in both compressed groups, the hydroscopicity of samples extracted by sodium hydroxide solution improved greatly, while that of samples extracted by warm water changed little, compared with that of water-saturated samples. Recovery of set and the change of hydroscopic environment inside wood were main reasons for the difference of water absorption among water-saturated samples and samples extracted with warm water and sodium hydroxide solution. The swelling rate of samples extracted by sodium hydroxide solution significantly increased. Moreover, the swelling rate in the tangential direction of tangentially compressed samples was obviously higher than that in radial direction of radially compressed ones. Dfs values of woods extracted by warm water and sodium hydroxide solution decreased by 0.002 and 0.007 in a radially compressed group and by 0.013 and 0.013 in a tangentially compressed group, compared to those of water-saturated one. Therefore, the conclusion can be made that the extraction and compression treatments used in this study have no obvious effects on internal wood surface.     

微波辅助提取不同品种油橄榄叶及果渣多酚物质

为比较不同品种油橄榄叶果之间多酚含量的差异,以云南引种的16个品种油橄榄叶样及13个品种的果渣样为原料,采用4因素3水平正交试验设计,选出微波辅助提取油橄榄多酚物质最优水平组合为：萃取功率为600 W、萃取时间为20 min、萃取温度为120℃、乙醇-水溶液浓度为40％,以此为微波萃取工艺条件,提取油橄榄叶样及果渣样中多酚物质,并测其含量。结果表明,叶样多酚含量鄂植8号中的最低,为1.02％,城固53中最高,为8.29％;果渣样品中多酚含量,阿斯最低,为0.64％,而莱星最高,为1.56％,油橄榄叶样中多酚含量平均值（4.21％）大于果渣中多酚平均含量（1.10％）。实验结果为从油橄榄中获取天然抗氧化剂,以延伸油橄榄产业链提供理论依据。     

落叶松外生菌根根际真菌种群结构研究

采用稀释平板法分别对落叶松外生菌根根际和非根际土壤共36个样品的真菌进行了分离和鉴定。研究结果表明,从落叶松菌根根际分离到101株真菌,共鉴定出真菌18个属;菌根根际真菌的优势类群为拟青霉、木霉、青霉;亚优势种群为毛霉及茎点霉。木霉在菌根根际土壤中分离频率最高为100%,在数量上菌根根际真菌高出对照1.7～4倍。     

人工林杉木木材力学性质对高温热处理条件变化的响应

以人工林杉木为试材,分别用空气和菜子油为介质,在温度为180,200和220 ℃对其分别热处理1,3和5 h,研究试材的抗弯强度(MOR)、抗弯弹性模量(MOE)、顺纹抗压强度、表面硬度对高温热处理条件变化的响应,同时对处理材的主要化学成分进行分析,用扫描电镜对处理材横切面微观结构进行观察.结果表明:人工林杉木试材的4种主要力学性质对不同条件热处理的响应程度不同.无论是空气热处理还是油热处理,试材的MOR,MOE,顺纹抗压强度与对照比有不同程度的降低,且随处理温度升高、时间延长,下降幅度增大,相比于时间,温度的影响更显著;180 ℃热处理1,3和5 h时,试材的MOR,MOE与对照比未发生明显变化(降幅在3%以内),而顺纹抗压强度则明显低于对照,两介质中降低幅度分别在3.29%～9.58%和3.89%～7.18%;200 ℃以上处理时,不同时间处理的3种主要力学性质不仅显著或极显著低于对照,且各性质问的差异也达显著或极显著水平;对硬度的测试结果表明:180 ℃热处理时,试件的径面硬度和弦面硬度均随时间的延长而增大;200 ℃热处理3 h时,试件的硬度达最大,与对照差异达显著水平;随后热处理试件的硬度开始降低,220 ℃热处理5 h后试件的硬度又明显低于对照.在隔氧的油介质中进行热处理,4种主要力学性质的变化程度低于空气介质处理材,当温度高于200 ℃时,两介质处理间的差异达显著水平.而热处理过程中木材主要化学组成与横切面微观结构变化的差异,反映了4种主要力学性质对不同条件热处理时表现出的响应差异.     

尾矿料的渗透性试验

渗透系数是直接影响尾矿坝浸润线埋深及稳定性的重要参数之一.分别对取自尾矿坝区的4种尾矿料进行颗粒分析试验、原状土与重塑土渗透试验、尾矿浆水渗透试验,分析了颗粒级配、孔隙比及时间对尾矿料渗透系数的影响.试验结果表明,由于重塑土不再具有分选性,其渗透系数比相近孔隙比的同类原状土大;经过80 min后,4种尾矿浆的渗透系数K20都趋向于同一个值.     

Evaluation of factors that have an influence on the fixation of chitosan in wood

When using chitosan as an antifungal agent in wood it is important to understand which factors contribute to a higher fixation ratio to optimize the utilization of chitosan, the active component. Small pine samples were impregnated with chitosan solutions varying in molecular weight, concentration, pH, polymerization agent, acid and degree of deacetylation. Different post-treatments such as time, temperature, moisture content and the effect of present air were applied to the samples to evaluate the effect on the relative retention. After impregnation, the samples, with a volume of 1.5 cm³, were leached in separate test-tubes according to EN-84. The samples were prepared in a paired design where both samples were impregnated, but only one was leached. Both leached and unleached samples were analysed for their chitosan content, and the relative ratio was used as a measure for the relative retention of chitosan during leaching. The results from these trials show that pH in the range of 5.1-5.9 is favourable. The molecular weight should be as high as possible yet able to penetrate the wood structure, and the use of acetic acid gives far better fixation than the use of hydrochloric acid.     

Surface quality and hardness of eastern redcedar as function of steaming

The objective of this study was to evaluate influence of steam treatment on surface quality and hardness of eastern redcedar (Juniperus virginiana L.). Defect-free samples with dimensions of 40 mm by 50 mm in by 20 mm were used for the tests. Specimens were exposed to steam having a temperature of 130 °C for 1-h and 3-h periods of time. Surface roughness of the samples at initial and exposed conditions was determined using stylus type equipment across the grain orientation on tangential surface of each sample. Janka hardness of the control and treated samples was also determined on Comten testing system. Based on the findings in this work, no significance was found between surface roughness values of the specimens steamed for 1 and 3 h. However, both types of steamed specimens had higher average roughness values ranging from 52 and 60 % than those of control samples. It appears that 3-h steaming adversely influenced hardness of the samples reducing its 9 % as compared to those of control samples. Densification effect of steaming on the samples was also evaluated using scanning electron microscope (SEM) and it was determined that steaming had some crushing effect on the cell wall.     

Resistance of mechanically densified and thermally post-treated pine sapwood to wood decay fungi

This paper evaluated the density and biological resistance of pinewood samples modified with thermo-mechanical densification and thermal post-treatment. The samples were densified with 20 and 40% compression ratios at either 110 or 150 °C. The thermal post-treatment was then applied to the pine samples at 185 and 212 °C for 2 h. These samples were exposed to white-rot (Trametes versicolor) and brown-rot (Coniophora puteana) fungi for twelve weeks and the resulting mass loss was determined. In the densified samples, the effects of the compression ratio on T. versicolor-initiated mass loss and of the compression temperature on C. puteana-initiated mass loss were found to be significant. The mass loss was less in the samples compressed at 150 °C with the 40% ratio, while the highest mass loss was observed in the undensified samples. In the thermally post-treated samples, the resistance to both decay fungi was significantly increased with the increase of the treatment temperature. The mass loss in the thermally post-treated samples at 212 °C after T. versicolor and C. puteana fungi testing was reduced by 73 and 67%, respectively. However, the effect of the densification processes on decay resistance in the thermally post-treated samples was insignificant.     

华山松针叶表皮结构与抗疱锈病关系的初步研究

通过对来自云南4个华山松疱锈病典型发病区的122份华山松针叶样本的解剖结构研究,发现华山松的感病组与健康组之间在针叶表皮结构上有显著差异,其中主要差异为表皮细胞厚度和角质膜厚度,有抗病特性的植株具有显著加厚的针叶表皮结构,抗病的健康组比感病组的角质膜和表皮分别增厚达30.5%和8.0%,而气孔数量和内皮层厚度上差异不明显.结果支持疱锈菌感染华山松是通过主动侵入机制从表皮进入针叶,角质膜厚度和表皮厚度对华山松抵抗疱锈菌感染有重要作用.这一结果为弄清疱锈菌侵入华山松的途径提供了实验证据.     

热处理材的铣削加工性能分析

考察热处理对木材机械加工性能的影响,为优化热处理材的加工工艺提供借鉴,在本试验确定的加工参数条件下,对热处理柞木进行了铣削加工。试验结果表明,相比对照材,铣削加工热处理材时刀体的温度更低,在加工过程中排放的较小粒径粉尘的比例增加,热处理材加工面的粗糙度与对照材并没有显著差异。     

Determination of physical and chemical properties and degradation of archeological Japanese cypress wood from the Tohyamago area using near-infrared spectroscopy

Here, we evaluated the application of near-infrared (NIR) spectroscopy for estimating the degradation level of archeological wood samples from the Tohyamago area, the dendrochronological ages of which were also determined. The wood samples were radially cut from three logs obtained from the Tohyamago area. NIR reflectance spectra were measured from the tangential faces of air- and oven-dried wood samples using a Fourier transform NIR spectrophotometer. The second derivative spectra within the wavenumber range of 6400–5200 cm^?1, in which the effect of moisture content in wood is suspected to be insignificant, showed a characteristic behavior with age. By comparing the second derivative spectral change in our wood samples with that in wood degraded by aging, thermal treatment, fungal attack, and lightning reported in the literature, we found that the second derivative spectra of wood samples from one log was similar to those of wood degraded by hygro-thermal treatment, whereas those of wood samples from another log was similar to those of wood degraded by brown-rot fungi. The physical and chemical properties of archeological wood were well predicted using a combination of partial least square regression analysis and NIR spectroscopy.     

Evaluation of factors that have an influence on the fixation of chitosan in wood

Abstract

When using chitosan as an antifungal agent in wood it is important to understand which factors contribute to a higher fixation ratio to optimize the utilization of chitosan, the active component. Small pine samples were impregnated with chitosan solutions varying in molecular weight, concentration, pH, polymerization agent, acid and degree of deacetylation. Different post-treatments such as time, temperature, moisture content and the effect of present air were applied to the samples to evaluate the effect on the relative retention. After impregnation, the samples, with a volume of 1.5 cm³, were leached in separate test-tubes according to EN-84. The samples were prepared in a paired design where both samples were impregnated, but only one was leached. Both leached and unleached samples were analysed for their chitosan content, and the relative ratio was used as a measure for the relative retention of chitosan during leaching. The results from these trials show that pH in the range of 5.1–5.9 is favourable. The molecular weight should be as high as possible yet able to penetrate the wood structure, and the use of acetic acid gives far better fixation than the use of hydrochloric acid.     

Biological control of decay in Douglas Fir poles — seven years perspective

Ten, creosote treated, Douglas-fir poles infected with Poria carbonica at the ground line zone were inoculated artificially with Scytalidium sp. FY strain in January 1967. FY became established in the poles. One pole was set aside for comprehensive sampling and thirty-six samples were taken from the ground line zone of it seven years later (January 1974). One sample yielded live FY, 2 samples yielded bacteria, 9 samples showed scanty fungal growth and 24 samples yielded no microorganisms. None of the 36 samples showed advanced decay or Poria carbonica. These observations are consistent with the mechanical condition of the wood in the other 9 poles inoculated with FY after decay had begun.     

皖北杨树二元立木材积表的编制

以安徽省杨树人工林为研究对象,按照立木材积表编制要求,随机抽取329棵杨树伐倒木材积资料.以300棵样木资料为编表样本,选用3种数学模型为二元材积的候选模型,利用非线性麦夸特迭代求解法确定各模型参数、剩余标准差、相关指数.根据相关指数和剩余标准差,确定最优二元材积模型为:V=0.000 096 93d2.0123h0.6147".以29棵样木资料为验表样本,分别计算二元材积模型理论材积与实际材积的平均相对误差、平均绝对相对误差和系统误差,计算结果为:二元材积表分别是2.7%、8.6%、0.1%.各种材积误差均满足林业生产材积估算误差要求.     

PEG bulking of wood cell walls as affected by moisture content and nature of solvent

Movement of polyethylene glycol (PEG) 1000 from wood cell lumens into adjacent cell walls was studied for different cell wall moisture contents (MCs) and PEG solvents; relative amounts of PEG that penetrated into the cell walls were estimated by Raman microscopy. It was shown that samples treated with PEG from chloroform solution adsorb less PEG than samples treated with PEG-water solution even in the case of samples with open cell wall structure near fibre saturation point MC. Reconditioning of PEG-chloroform treated samples at high relative humidities enhanced PEG bulking of cell walls, but not to the maximum amounts observed with PEG-water treatments. Raman microscopy was a useful tool for estimating relative PEG amounts in the cell walls.     

实木拼接板胶合性能及其破坏形式

对铁杉木、橡胶木和北美核桃木拼接板的胶层耐久性能、侧拼抗剪和指接抗弯强度进行了检验.结果表明:侧拼胶层通过Ⅰ类浸渍剥离试验要求,指接胶层不能完全满足Ⅱ类浸渍剥离要求,破坏形式主要有胶层开裂和边齿脱落 ;侧拼抗剪强度低于木材顺纹抗剪强度5％,指接抗弯强度是木材抗弯强度的26.2％～77.9％,破坏形式主要有指接胶层开裂、指榫折断及木材撕裂.     

我国西北干旱地区森林土壤中苏云金芽孢杆菌生态分布

对地处我国西北干旱地区新疆、甘肃、宁夏三省（区）内的１１个自然保护区－－哈纳斯、小叶白蜡、天山云杉、野核桃、塔里木、东大山 山、六盘山、崆洞山、兴隆山、莲花山等自然保护区采集的２６０个森林土壤样品,进行了生态因子调查：分析了土壤ＰＨ、含水量、水解Ｎ、有效、速效Ｋ、全Ｎ、有机质;研究了芽孢杆菌、苏云金芽孢杆菌数量和种类生态分布。共分离苏云金芽孢杆菌４２株,其出土率和分离率分别为１１．５３％和２．１８     

松口蘑种质资源的RAPD分析

利用RAPD标记技术分析中国主产区和日本松口蘑的亲缘关系.结果表明:供试样品聚为3类,且供试松口蘑之间遗传距离较近,表明它们是一个物种下的不同居群.     

The ultrastructure of cellulose from wood

Summary During the delignification of wood several processes overlap one another. One of these is the penetration of the wood samples by the delignifying solution. Penetration tests under different conditions show that there is almost no difference in the penetration depth of wood samples penetrated by diffusion only and of wood samples treated with pressure. In both cases the pits are closed during the flow of fluids. Vacuum treated samples show better penetration and most of the pits in these samples remain open. The distribution of fluids within the cell walls takes place in the intercellular spaces, in small openings in the compound middle lamella and in the secondary wall 1 as well as in very fine pores in the secondary wall 2. The penetration of a wood sample is greatly facilitated if the sample is mechanically injured. A slowly proceeding delignification with ethylene sulphite shows that the delignification obviously starts in the S 1 layer and proceeds from there towards the compound middle lamella and the S 2 layer. In the first stages of lignin removal the compound middle lamella is also attacked, the attack beginning at the border of the pit chambers.     

林业中常用的一种分析方法—聚类分析

聚类分析的基本思想是研究的样品或指标（变量）之间存在着的程度不同的相似性（亲疏关系），根据一批样的多个观测指标，具体找出一些能够度量样品或指标之间相似程度的统计量，以此为划分类型的依据，将一些相似程度较大的样品（或指标）聚合在同一类，而将关系疏远的聚合在不同的类，把不同的类型一一划出来，形成一个由小到大的分类系统。最后将整个分类系统绘制成一张聚类图（或称谱系图），并由聚类图进行分类。