Degradation of boards of Eucalyptus globulus Labill. and Eucalyptus camaldulensis Dehnh. during air drying

Boards of E. globulus and E. camaldulensis were air dried, with the objective to show that the available resources in Ethiopia can be utilized in a simple way without involvement of high technology. The degradation of most of the boards after air drying was acceptable according to Australian Standards. Deformation values, often increased after conditioning, could mostly be reduced to an acceptable level by planing. No statistically significant relations could be shown between density and check formation. The density values of heartwood and sapwood are significantly different in both species with the higher density in the sapwood. The re-sawing of the boards of E. camaldulensis along the pith has arrested the further check formation during drying, probably due to release of stresses. When planning air drying in Ethiopia, one should carefully select the dimensions of the wood and the conditions in which the material are exposed.     

蓝桉叶挥发油化学成分的气相色谱-质谱分析研究

目的研究云南产蓝桉叶挥发油的化学成分.方法采用水蒸气蒸馏法提取云南产蓝桉叶挥发油,经气相-质谱联用仪分析其成分,采用峰面积归一化法计算各组分的相对含量.结果确定了云南产蓝桉叶挥发油中47个化合物,所鉴定成分占总馏出峰面积的99.17%,其主要成分是1,8-桉叶素(72.71%),α-蒎烯(9.22%),α-松油醇醋酸酯(3.11%),(-)-蓝桉醇(2.77%),α-松油醇(2.54%),别香橙烯(2.47%).结论确定了云南产蓝桉叶挥发油的化学成分,为综合利用云南产蓝桉叶挥发油奠定了基础.     

Kiln drying of sawn boards of youngEucalyptus globulus Labill. andEucalyptus camaldulensis Dehnh. grown on the Ethiopian Highlands

Two drying schedules, a higher- and a lower temperature drying schedule, were tried on sawn boards from youngEucalyptus globulus andEucalyptus camaldulensis grown in Ethiopia. The aim of the study was to investigate the effect of the two schedules on seasoning degradation and to develop recommendations concerning drying schedules for the examined timbers. Both seasoning schedules gave satisfactory degradation results for 32 mm thick juvenileE. globulus andE camaldulensis boards, even though the degradation obtained using the low temperature drying in most cases was slightly lower than using the high temperature drying. The boards ofE. camaldulensis generally proved to have less degradation than the boards ofE. globulus in this study. The conditioning of kiln dried materials in the conditioning room has reduced the extent of seasoning degradation in most cases. Kiln conditioning has also reduced deformation values to a certain extent, but often not checking values. In evaluating the differences between the upper- and butt logs, it is found that there were no consistent differences between them, except that the 2m longE. camaldulensis boards from butt logs had more deformation than those from upper logs. End sealing with silicon paste gave generally better results than unsealed boards with both drying schedules.     

蓝桉叶精油对砂糖橘的保鲜效果

旨在探明蓝桉叶精油对耐藏性较差的砂糖橘的保鲜效果。采用0.25%、0.50%、0.75%和1.00%四种浓度蓝桉叶精油乳液浸泡砂糖橘60 s,在常温下贮藏,定期进行检测,通过生理生化指标及好果率对保鲜效果进行评价。研究结果表明,与对照相比,蓝桉叶精油处理可显著降低采后砂糖橘的呼吸强度,有效延缓砂糖橘果肉中总糖、VC和可滴定酸(TA)含量的下降速率,明显减少砂糖橘的腐烂损失,有效提高其果皮超氧化物歧化酶(SOD)和过氧化物酶(POD)的活性。四种不同浓度蓝桉叶精油处理相比,0.75%处理组的保鲜效果要明显好于其它处理组,而1.00%处理组可能存在轻微药害。研究结果提示,蓝桉叶精油是一种极具开发利用潜力的砂糖橘天然保鲜剂。      

Relationship between transverse shrinkage and tension wood from three provenances of Eucalyptus globulus Labill

was studied using 12 mm increment cores taken from straight, vertical and dominant trees of three provenances from a plantation near Tarpina, South Australia. Tension wood fibre percentages were determined from microscopic examination of stained transverse sections and transverse shrinkage was measured from cores dried to 17% equilibrium moisture content. Shrinkage before and after steam reconditioning, as well as associated collapse, were related to the proportions of tension wood. Contrary to normal expectations, high levels of tension wood produced greater shrinkage in the sapwood than in the heartwood in material from all provenances. Collapse was significantly greater in material from the Jeeralang and Western Tasmania provenances than in the King Island provenance. While the mean proportion of tension wood was highest (4.3%) in material from Jeeralang and least from King Island (2.4%), no significant difference among the three provenances was evident for proportions of tension wood fibres when considering only the last year's growth. Variation in the width of the gelatinous layer (G-layer) was recorded for the tension wood fibres. Fibres with thin walled G-layers were usually scattered among normal fibres and collapsed regions containing such material generally recovered after reconditioning. On the other hand, regions containing the more typical tension wood fibres, with thick walled G-layers, exhibited high levels of shrinkage and collapse, and poor recovery after reconditioning.     

Relationship between transverse shrinkage and tension wood from three provenances of Eucalyptus globulus Labill

Eucalyptus globulus was studied using 12 mm increment cores taken from straight, vertical and dominant trees of three provenances from a plantation near Tarpina, South Australia. Tension wood fibre percentages were determined from microscopic examination of stained transverse sections and transverse shrinkage was measured from cores dried to 17% equilibrium moisture content. Shrinkage before and after steam reconditioning, as well as associated collapse, were related to the proportions of tension wood. Contrary to normal expectations, high levels of tension wood produced greater shrinkage in the sapwood than in the heartwood in material from all provenances. Collapse was significantly greater in material from the Jeeralang and Western Tasmania provenances than in the King Island provenance. While the mean proportion of tension wood was highest (4.3%) in material from Jeeralang and least from King Island (2.4%), no significant difference among the three provenances was evident for proportions of tension wood fibres when considering only the last year's growth. Variation in the width of the gelatinous layer (G-layer) was recorded for the tension wood fibres. Fibres with thin walled G-layers were usually scattered among normal fibres and collapsed regions containing such material generally recovered after reconditioning. On the other hand, regions containing the more typical tension wood fibres, with thick walled G-layers, exhibited high levels of shrinkage and collapse, and poor recovery after reconditioning.

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基于激光扫描成像技术的锯材裂缝和孔洞缺陷视觉识别系统

利用激光扫描技术形成了待检测材面的轮廓信息,把激光位移传感器输出的轮廓距离信息转换成图像的象素值而形成轮廓图像.根据裂缝和孔洞缺陷的形状特征,在统计的基础上提取了裂缝和孔洞缺陷的四个识别特征,并在此基础上开发了用于裂缝和孔洞缺陷识别的八条规则.结果表明,所开发的基于激光扫描成像技术基础上的锯材裂缝和孔洞缺陷的视觉识别系统不仅可以正确表征裂缝和孔洞等厚度缺陷信息,而且该系统能够精确地定位和分类上述缺陷.     

澳大利亚及中国产桉叶油香气成份的研究

运用配毛细管色谱柱的安捷伦6890N气相色谱仪和6890N/5973N气相色谱质谱联用仪对原产于澳大利亚及移栽到中国的桉叶油挥发性组份进行分析,结果显示,由于澳大利亚和中国的地理、气候环境相差甚远,使得来自于这两地的桉叶油成份相应产生变化,香气也有所不同.本实验测得78个成份,并对其中的69个组份进行了定性定量.桉叶油的主要或份是桉叶油素,含量在80%以上,其它重要成份还有水芹烯、甲位松油烯、乙位蒎烯、对伞花烃和柠檬烯,在不同来源的桉叶油中这些组分的含量均不相同.     

The relationship between longitudinal growth strain and the occurrence of gelatinous fibers in 10 and 11-year-old Eucalyptus globulus Labill.

The potential for using growth strain measured at the stem periphery of standing plantation-grown Eucalyptus globulus Labill. trees as a non-destructive detection method for tension wood was assessed. Two trials were conducted 12 months apart in a 10 to 11 year-old provenance trial of E. globulus located in the Mt. Gambier region of south-eastern Australia. The relationship between the occurrence of gelatinous fibers over varying radial depths of wood tissue and growth strain measured at breast height was investigated. The percentage of gelatinous fibers in wood tissue laid down in approximately the two years prior to taking the growth strain measurement was found to correlate best with growth strain. In an expansion of this work, growth strain was found to be a good indicator of the presence of gelatinous fibers in wood tissue taken from the immediate position where growth strain was measured. Thresholds were found at approximately 800  ue, above which gelatinous fibers were common, and 1,200  ue where gelatinous fibers were always present in each of the three provenances assessed. Tension wood was found to increase in occurrence over the 12 month period in line with a trend of increasing occurrence and severity of tension wood found in earlier work in the plantation.     

蓝桉碱性亚硫酸钠化机浆配抄牛皮箱板纸预处理工艺的研究

本文着重对蓝桉原料碱性亚钠法化学机械浆的化学预处理工艺进行了研究,以确定蓝桉碱性亚铵法化机浆磺化预处理的最优工艺条件。     

超声辅助水蒸气蒸馏法提取蓝桉叶中精油的工艺优化及其抑菌活性研究

目的初步探明蓝桉叶精油最佳提取工艺及不同提取工艺条件下蓝桉叶精油得率与其抗菌活性的差异性。方法以桉叶油得率为评价指标,采用超声辅助水蒸气蒸馏法,通过单因素与正交试验确定桉叶油最佳提取工艺。并检验正交试验各组合桉叶油对金黄色葡萄球菌、大肠杆菌和黑曲霉的抑菌效果。结果桉叶油的最佳提取工艺条件为料液比1:4(g/mL),超声时间25min,超声功率200W,蒸馏时间5h,桉叶油得率为1.51%。而抑菌试验结果表明,不同提取工艺所得桉叶油的抑菌活性存在差异。对金黄色葡萄球菌和大肠杆菌而言,料液比1:6(g/mL),超声时间30 min,超声功率180 W,蒸馏时间5 h时抑菌活性最强,抑菌圈直径分别为(11.92±0.20)mm(n=3)和(10.25±0.35)mm(n=3),对应的桉叶油得率为1.28%;对黑曲霉而言,料液比1:7(g/mL),超声时间30min,超声功率200W,蒸馏时间7h时抑菌活性最强,抑菌圈直径为(12.25±0.29)mm(n=3),对应的桉叶油得率为1.38%。结论精油得率与其抑菌活性无相关性,针对不同的目标微生物需要单独优化提取工艺来获得相应的微生物抑菌剂。     

The relationship between longitudinal growth strain and the occurrence of gelatinous fibers in 10 and 11-year-old<Emphasis Type="Italic"> Eucalyptus globulus</Emphasis> Labill.

The potential for using growth strain measured at the stem periphery of standing plantation-grown Eucalyptus globulus Labill. trees as a non-destructive detection method for tension wood was assessed. Two trials were conducted 12 months apart in a 10 to 11 year-old provenance trial of E. globulus located in the Mt. Gambier region of south-eastern Australia. The relationship between the occurrence of gelatinous fibers over varying radial depths of wood tissue and growth strain measured at breast height was investigated. The percentage of gelatinous fibers in wood tissue laid down in approximately the two years prior to taking the growth strain measurement was found to correlate best with growth strain. In an expansion of this work, growth strain was found to be a good indicator of the presence of gelatinous fibers in wood tissue taken from the immediate position where growth strain was measured. Thresholds were found at approximately 800 uε, above which gelatinous fibers were common, and 1,200 uε where gelatinous fibers were always present in each of the three provenances assessed. Tension wood was found to increase in occurrence over the 12 month period in line with a trend of increasing occurrence and severity of tension wood found in earlier work in the plantation.     

蓝桉化学热磨机械浆DTPA螯合预处理

研究了蓝桉化学热磨机械浆DTPA常规螯合预处理条件,探讨了DTPA置换螯合预处理的可能性.结果表明DTPA常规螯合预处理可以在80～90℃较高温度下进行,并在5min内快速完成.对于蓝桉单段H2O2置换漂白的漂后浆白度,螯合预处理效果的好坏顺序为DTPA置换螯合预处理＞DTPA常规螯合预处理＞EDTA常规螯合预处理.     

漂液的穿透特性对蓝桉CTMP H2O2置换漂白的影响

研究了包含穿透曲线、穿透时所用漂液量和漂液穿透时的表观流速等因素在内的穿透特性对单段蓝桉CTMP过氧化氢置换漂白的影响.结果表明在实验用置换漂白反应器中进行H202置换漂白实验时,存在较严重的沟流现象,要用约2倍于浆层中液体的漂液才能基本置换完浆层中的液体;漂液穿透浆层时的表观流速对漂白有较大影响,漂后浆白度和H2O2消耗量都随表观流速增加而下降.     

桉木CTMP制浆废液水质特征及色度特性分析

采用不同工艺及设备模拟CTMP工艺,得到了桉木CTMP废液.探讨了不同工艺条件下废液的水质参数、可生化性、污染物质、分子质量及色度等.研究结果表明,桉木CTMP制浆废液污染负荷高,可生化性一般,色度深且随pH值升高显著加深.木素衍生物和多酚类物质的酚羟基的离子化及与金属离子的络合是废液色度深的主要原因.相对分子质量大于10000的有机组分是色度的主要构成.混合制浆时,桉木比例越大,色度越深,C0D负荷相对较小;预处理段和磨浆段污染负荷表现出与全桉木相反的情况,可能原因是混合磨浆过程中两者的溶出物发生进一步反应,有利于更多物质的溶出.     

P因子对桉木水预水解及后续KP法制浆的影响

利用水预水解法先提取桉木片中的半纤维素,然后对水解后的木片进行硫酸盐法蒸煮。探讨了P因子(预水解因子)与水预水解及后续KP法制浆结果之间的关系,研究了水预水解提取液中戊糖和糠醛等成分随P因子变化的特点,以及P因子与浆料得率、卡伯值、黏度及物理强度之间的关系,分析了P因子变化对提取液和黑液中糖类组分的影响。     

桉木硫酸盐浆木聚糖酶漂白的研究

对桉木硫酸盐浆木聚糖酶漂白的研究作了介绍。具体讨论了木聚糖酶漂白的机理和漂白时的影响因素,然后对几种具体的桉木硫酸盐浆的木聚糖酶漂白的工艺流程作了介绍,最后对木聚糖酶漂白的趋势和研究方向作了论述。