单宁树脂油松大片刨花板的研制

介绍以油松为主要原料,单宁树脂为胶粘剂,在实验室条件下,进行单宁树脂油松大片刨花板的研制。同时,对产品的复合工艺和主要影响因素进行了系统地研究,找出其最佳制备工艺参数。     

Antennal responses of the two host races of the larch bud moth,Zeiraphera diniana,to larch and cembran pine volatiles

The larch bud moth (LBM) Zeiraphera diniana Guenée causes defoliation on larch in the Alps at 8- to 10-year intervals, after which populations crash. There are two LBM host races, one on larch and the other on cembran pine. These host races are morphologically indistinguishable as adults but they differ genetically in larval color types. Furthermore, females of each host race produce distinct pheromone blends and show oviposition preferences for their respective hosts. It is not clear to what extent host choice contributes to assortative mating in the LBM. Here, we compare the olfactory sensitivities of the two host races to the odors of fresh foliage of the host plants using the electroantennogram (EAG) technique, and the responses of the two host races to volatiles collected from the two host plants as analyzed by gas-chromatography-linked antennographic detection (GC-EAD). Both sexes of the larch and cembran host races show the same EAG responses to vapors of fresh larch and cembran pine foliage. Fifteen plant volatiles identified as chemostimuli by GC-EAD from larch and cembran pine odors elicited the same antennogram responses from the two host races. However, the GC-EAD analyses indicate that the number and quantity of chemostimuli emanating from each host plant is different. It is, therefore, most probably the array of olfactory receptors responding to the bouquet of volatiles unique to each host plant that underlies the host preferences of the two races. What remains open is the extent to which the similarity of the olfactory systems may contribute to cross-attraction. The fact that LBM individuals with intermediate characteristics between the two host races exist, suggests that olfactory perception does not hinder gene flow and contributes to sustained genetic diversity within the species Z. diniana.     

Performance of a DI diesel engine fuelled by blends of diesel and kiln-produced pyroligneous tar

This paper presents results of experiments undertaken to determine the performance of a direct injection (DI) diesel engine fuelled by blends of kiln-produced pyroligneous tar (PT) and diesel. The PT was sourced from Bulgaria where it was produced from a pine feedstock via a traditional kiln method that involves separation of the aqueous pyroligneous acid fraction. The tar is characterized by high carbon concentration, viscosity and high heating value. Although high, at fuel injection temperatures over 120 °C the tar's viscosity is likely to be lower than diesel. Analysis by GC revealed a number of compounds typically extracted from wood-based tar products. Blends containing 20% and 40% PT with diesel were tested in a 4-cylinder, 4-stoke DI diesel engine. The blends are stable and readily formed. Little difference in engine performance relative to diesel was found for 20% PT blends. PT blends (40%) exhibit significantly higher in-cylinder gas temperature and pressure. Ignition delay for both blends is longer than diesel, as is the fuel burn rate during the premixed stage of the combustion. During the diffusion stage of combustion, the fuel burn rate is lower relative to diesel. The performance of engines fuelled by blends containing 40% or more PT could be improved through optimization of engine systems.     

湿地松深度脱木素硫酸盐法蒸煮过程中木素结构的变化（Ⅱ）——黑液中深出木素结构的变化

采用^13C-NMR和^31P-NMR,进行了湿地松深度脱木素硫酸盐法蒸煮过程中木素结构的变化的研究。本文研究黑液中溶出木素结构的变化,着重分析了溶出木素中脂肪羟基、酚羟基、β-O-4结构和缩合结构含量的变化。     

添加多硫化钠的马尾松硫酸盐法蒸煮特性

研究了添加多硫化钠硫酸盐法蒸煮的特性.结果表明,多硫化钠用量、小保温温度以及小保温时间对马尾松纸浆的得率、卡伯值和粘度均有较明显的影响.在一定范围内,增加多硫化钠用量,采用相对合理的较高的小保温温度以及适当延长小保温时间有益于提高纸浆得率,改善脱木质素的选择性.     

湿地松板材的酸性脱脂技术

用新研制的酸性脱脂液对速生人工林湿地松板材进行低浴比汽蒸处理,处理后,板材保持了新鲜材材色,物理力学性能下降也不明显,可做室内装饰、实木地板和家具等用材。     

Survival of pine sawflies in cocoon stage in relation to resin acid content of larval food

Several experiments were conducted to determine whether the ingestion of diterpenoids (resin acids) by pine sawfly larvae influences the survival of postlarval stages. Larvae of two diprionid sawfly species were reared on shoots of two Scots pine clones, one with a low (1.5% dry wt) concentration of resin acids and the other with a high (5.2% dry wt) concentration. No significant treatment-related differences were found in any of the experiments with respect to (1) resistance against parasitoids, (2) preference of predatory shrews and carabids, and (3) apparency of cocoons in the field to predators. A preference of sawfly prepupae to spin cocoon in feces from larvae reared on high resin acid needles was found. Possible explanations for these results are discussed. Detection of an unknown compound, possibly a breakdown product of the major resin acid in pine needles (pinifolic acid), in prepupae indicate that resin acids may be metabolized by the sawflies.     

Seasonal variation in phytotoxicity of bracken (Pteridium aquilinum L. Kuhn)

Laboratory bioassays were used to test for the phytotoxicity of volatile compounds, fresh plant material as a seed bed, and water extracts from bracken [Pteridium aquilinum (L.) Kuhn] pinnules to germination and seedling growth of aspen (Populus tremula L.) and Scots pine (Pinus sylvestris L.). Fronds were sampled from two bracken populations, one in the south and one in the north of Sweden. All three bioassays showed inhibitory effects, and these varied seasonally with the most inhibitory effects occurring in May, June, and September. The peak of inhibition in May and June coincides with the start of the growing season when bracken still is immature and vulnerable to interference from other species. The increase in inhibitory effects in September appears to be due to transformation of natural products or an accumulation of inhibitory compounds that are released during decomposition following frond death. Addition of activated carbon did not remove the inhibitory effects.     

(+)-Juniperol and (+)-pimaral: Attractants for the cerambycid beetle,Monochamus alternatus Hope

A sesquiterpene and a diterpene were isolated from sound pines and identified as (+)-juniperol and (+)-pimaral, respectively. The combination of these compounds in a certain ratio induced a significant laboratory flight response by the female cerambycid beetle,Monochamus alternatus Hope. Individual compounds elicited a limited response only.     

Dynamics of macronutrients during the first stages of litter decomposition from forest species in a temperate area (Galicia,NW Spain)

The decomposition and dynamics of nutrient elements was studied for leaves and twigs from Quercus robur, Pinus radiata and Eucalyptus nitens in soils developed from granodiorite, slate and limestone in Galicia, NW Spain. Two 1-ha plots were selected for each material-vegetation combination, making a total of 18 plots. Litter decomposition and nutrient dynamics during the first six months were investigated using litterbags. Mass loss was higher for leaves than twigs and not significantly different for different tree species. Mass loss correlated significantly with carbon loss (r = 0.96 for leaves, r = 0.90 for twigs). As a general trend, nutrient release from leaves and twigs was greater for the broadleaved species (eucalyptus and oak). K and S were rapidly released from all litters, while Ca and Mg showed the highest tendency to be immobilised. N and P behave similarly, with a final balance of net release. Soil parent material did not significantly influence decomposition or nutrient dynamics.