软木无胶胶合工艺研究

以探索新型环保的无胶软木产品为目的,在现有软木材料性质、结构的研究及木质材料自粘胶合理论基础之上,以热压时间、含水率、热压温度、配坯密度为因素,采用正交试验法进行软木无胶胶合工艺的研究。结果表明:软木材料可在一定条件下自粘合成板,且制成的无胶软木板性能优良。在实验条件下得到的较优软木无胶胶合工艺参数为:热压温度140 ℃,含水率12%,热压时间5 min,配坯密度0.7 g·cm^-3。     

Bacterial community associated with the ambrosia beetle Platypus cylindrus on declining Quercus suber trees in the Alentejo region of Portugal

In Portugal, the oak pinhole borer Platypus cylindrus and its mycobiota have been associated with cork oak (Quercus suber) death, but no knowledge exists regarding the associated bacterial community. However, it is known that some bacteria are important for ambrosia beetle symbiosis and play a role in oak tree health. To explore the bacteria associated with this beetle and its host, with the ultimate goal of highlighting potential roles in oak decline, this study used a culture-dependent approach for strain isolation and phylogenetic identification using 16S rRNA gene sequencing and multilocus sequence analysis (MLSA). The bored galleries of different cork oak trees from a cork stand in Alentejo, together with the body and mycangia of adult beetles, were investigated. The samples revealed a diverse community comprising 500 isolates with 64 distinct types of bacterial colonies. Sixty-eight strains were selected for sequencing and used for phylogenetic analysis, 40 from wood galleries and 28 from beetles. Thirty-two genera of bacteria were identified, 18 of which were described for the first time within oak–beetle interactions. Major taxonomic groups were Actinobacteria in beetles and Enterobacterales in wood galleries. Although specific oak bacterial pathogens were not detected, a group of distinct strains detected in wood galleries, potentially belonging to a new Pectobacteriaceae species, were able to produce mild symptoms on cork oak plantlets. This study reports for the first time the biodiversity of culturable bacteria associated with the Q. suber–P. cylindrus interaction, their relevance to both organisms and the possible contribution to oak decline.     

水库淤积物建材化利用研究

广东省水库淤积严重,造成了众多的危害,水库淤积防治势在必行。以广东省兴宁合水水库淤泥为主要原材料,以当地的炉渣、煤矸石、页岩为添加剂,进行制砖试验研究。研究表明,用水库淤泥单独制造烧结砖不能满足工艺技术和产品标准要求;利用水库淤泥为主要原料,掺加煤矸石、页岩或炉渣等物料,以调节水库淤泥中化学成分和矿物组成,调整水库淤泥的各项物理性能,能够生产出符合产品标准要求的烧结砖,强度等级可达到MU10以上,其中掺入页岩配比的强度最高。炉渣中含有大颗粒的石灰质颗粒,会造成烧结样品出现石灰爆裂,产业化中需要选择不含石灰质颗粒的炉渣作为外掺料。水库淤积物中的粗颗粒通过恰当处理,可以作为混凝土细骨料。     

不同群体栓皮栎栓皮性状变异分析

对陕西境内10个栓皮栎群体栓皮性状变异情况进行了试验分析.结果表明,栓皮栎树皮颜色、开裂方式、厚薄方面存在明显的表型变异;测定的6个性状在不同群体之间差异达极显著水平,同一群体不同个体之间在栓皮细胞宽、细胞数目和栓皮厚指标有显著差异;初步认为栓皮栎栓皮性状改良以群体改良为主;10个群体中太白3、南五台3群体可作为最优群体.     

软木膨化处理现状与发展趋势

软木是一种具有独特性能的天然产品,因而得到广泛的应用。本文介绍了国内外对软木原材料进行软化、膨化处理的工艺现状及材料的性能变化,探讨其发展趋势。通过对比分析认为,在压力作用下的热-化学膨化方法效果较好,可以使软木膨胀到原体积的70%～220%,密度减轻,弹性和柔韧性增加;膨化后软木不产生炭化,不失去软木原有的自然色泽,是生产高档软木产品的发展趋势。     

软木的热解特性和热动力学研究

软木是一种天然多孔性绿色材料,具有吸音减震、隔热保温、滞火阻燃、耐酸碱、不易老化、富有弹性、无毒无味等一系列优良特性。由于它所独具的各种特性,特别是软木的热学性能,使其在工业生产与人民日常生活中都有广泛的应用。本文通过热重分析仪来研究软木的热学性能,在实验温度从303~873K的范围内,对产自湖北和云南的2种软木的热解过程进行了分析。结果表明:软木热解过程分为4个阶段,热解过程与化学成分的热解过程相一致,513~693 K是试样热解的主要阶段。根据热分解速率方程,获得了软木的动力学参数——频率因子A和活化能E,最后得到软木的热解动力学方程。     

Effects of fire temperature on the physical and chemical characteristics of the ash from two plots of cork oak (Quercus suber)

Cork oak, (Quercus suber) is widely distributed in the Mediterranean region, an area subject to frequent fires. The ash produced by burning can have impacts on the soil status and water resources that can differ according to the temperature reached during fire and the characteristics of the litter, defined as the dead organic matter accumulated on the soil surface prior to the fire. The aim of this work is to determine the physical and chemical characteristics of ash produced in laboratory experiments to approximate conditions typical of fires in this region. The litter of Quercus suber collected from two different plots on the Iberian Peninsula, Mas Bassets (Catalonia) and Albufeira (Portugal), was combusted at different temperatures for 2 h. We measured Mass Loss (ML per cent), ash colour and CaCO₃ content, pH, Electrical Conductivity (EC) and the major cations (Ca²⁺, Mg²⁺, K⁺ and Na⁺) released from ash slurries created by mixing ash with deionized water. The results showed that ML per cent is higher at all temperatures in Albufeira samples compared to Mas Bassets samples, except at 550°C, and the rate of loss increases faster with temperature than the Mas Bassets samples. At 150°C the ash colour is yellowish, becoming reddish at 200–250°C and black at 300°C. Above 400°C the ash is grey/white. This thermal degradation is mostly observed in Albufeira litter. The formation of CaCO₃ was identified at a lower temperature in Albufeira litter. At temperatures < 300°C, pH and EC values are lower, rising at higher temperatures, especially in Albufeira slurries. The concentration of cations at lower temperatures does not differ substantially from the unburned sample except for Mg²⁺. The cation concentration increases at medium temperatures and decrease at higher temperatures, especially the concentration of divalent cations. The monovalent cations showed a larger concentration at moderate temperatures, mainly in Albufeira ash slurries. The analysis of the Ca:Mg ratio also showed that for the same temperature, a higher severity results for Albufeira litter. Potential negative effects on soil properties are observed at medium and higher temperatures. These negative effects include a higher percentage of mass loss, meaning more soil may be exposed to erosion, higher pH values and greater cation release from ash, especially monovalalent cations (K⁺, Na⁺) in higher proportions than the divalent ions (Ca²⁺, Mg²⁺), that can lead to impacts on soil physical properties like aggregate stability. Furthermore, the ions in ash may alter soil chemistry which may be detrimental to some plants thus altering the recovery of these ecosystems after fire. Low intensity prescribed fire can be a useful tool to land management in these sites, due to the reduced effects of fire temperatures on the physical and chemical properties of surface litter, and can reduce the risk of high temperature wildland fires by reducing fuel loadings. From the perspective of water resources, lower fire temperatures produce fewer impacts on the chemistry of overland flow and there is less probability that the soil surface will be eroded. Copyright © 2009 John Wiley & Sons, Ltd.     

Cork and guar gum supplementation enhanced the buoyancy of faeces,and protease supplementation alleviated the negative effects of dietary cork on growth and intestinal health of tilapia,Oreochromis niloticus × O. aureus

To evaluate the effects of dietary cork, protease and guar gum on growth, intestinal health and faecal floatability of tilapia, fine or coarse particle cork (0.45–0.60 mm, 0.60–0.83 mm) was included in diets at 0 (control), 20 g/kg, 30 g/kg and 40 g/kg, and then, 0.175 g/kg protease (P) and 3 g/kg guar gum (G) were supplemented to the 40 g/kg coarse particle diet individually or in combination (P + G). Tilapia with an initial body weight of 15.0 ± 0.5 g were fed one of the 10 diets for 60 days. The results showed that weight gain (WG), apparent digestibility coefficient (ADC) of dry matter (DM) and crude protein (CP), intestinal evacuation ratio, intestinal digestive enzyme activity (IDE) and villus height decreased, and floating faeces ratio increased with the increasing cork level in diets. At the same supplementation level, coarse particle groups showed significantly higher floating faecal ratio than fine particle groups (p < .05). Dietary protease increased the WG, ADC of DM, IDE and villus height (p < .05), and guar gum increased floating faecal ratio when compared to 40 g/kg coarse particle group (p < .05). However, the ADC of DM, IDE and villus height of protease group were still inferior to those of control group (p < .05). In conclusion, dietary cork increased the floating faeces ratio, and the coarse particles produced more floating faeces than fine particles. Moreover, the supplementation of guar gum in cork‐supplemented diet further increased the floating faeces ratio. However, dietary cork negatively affected the growth performance of tilapia, which could be partially alleviated by the supplementation of protease.     

陕西不同天然类型栓皮栎软木的主要化学组分及其利用分析

【目的】研究不同天然类型栓皮栎软木的主要化学组分,为栓皮栎的选型与培育以及充分利用栓皮栎软木资源提供理论依据。【方法】2010-07,从陕西商州区二龙山林场树龄33～50年的栓皮栎天然林中采剥栓皮厚度和裂纹深度不一的4种类型的栓皮栎软木,按照GB/T 2677《造纸原料的化学成分测定》中的方法对软木中的抽提物、木栓脂、纤维素和木质素进行测定与分析。【结果】4种类型栓皮栎软木的主要化学组分存在差异。抽提物总量质量分数的高低为薄皮浅裂型>厚皮深裂型>薄皮深裂型>厚皮浅裂型;木栓脂质量分数的高低为薄皮深裂型>薄皮浅裂型>厚皮深裂型>厚皮浅裂型;纤维素质量分数的高低为厚皮深裂型>厚皮浅裂型>薄皮浅裂型>薄皮深裂型;木质素质量分数的高低为薄皮深裂型>厚皮浅裂型>厚皮深裂型>薄皮浅裂型。【结论】综合分析比较主要化学组成对软木性能的影响,4种栓皮栎类型软木的优良性依次为：薄皮深裂型>薄皮浅裂型>厚皮浅裂型>厚皮深裂型。因此从软木性能方面考虑,首选薄皮深裂型。     

天然黄檗不同季节主要生物碱含量差异的研究

次生代谢产物小檗碱、掌叶防己碱和药根碱是黄檗中重要的药用生物碱,本研究在吉林省5 个林业局选取了65 株不同年龄的天然黄檗,利用反相高效液相色谱法研究了黄檗多器官中3 种生物碱含量的季节差异。结果表明:小檗碱在根皮、多年生枝、当年生枝和叶中的季节差异显著,各器官中小檗碱含量夏季最低(叶除外);叶中小檗碱含量,在各个龄组均表现为从春到秋含量依次升高,变化幅度在0.017 ~0.124 mg/ g 之间;小檗碱在根皮中最高, 平均值达到24.27 mg/ g,其余依次是茎皮、多年生枝皮、当年生枝和叶片。掌叶防己碱在根皮、茎皮、当年生枝、叶和幼龄阶段的多年生枝皮中的季节差异显著,秋季含量最高(叶除外);叶中掌叶防己碱含量,在各个龄组均表现为春季最高;掌叶防己碱在茎皮中含量最多,平均值为7.02 mg/ g,其余含量由大到小依次是多年生枝皮、根皮、当年 生枝和叶。药根碱在茎皮、多年生枝皮、当年生枝、叶和成熟阶段的根皮中的季节差异显著,多数器官夏季含量最 低;叶中药根碱含量,在各个龄组均表现为春季最高;药根碱在各个器官中的分布规律与小檗碱一致,根皮中含量最高,平均值为0.84 mg/ g,其余含量由大到小依次是茎皮、多年生枝、当年生枝叶。