用松节油或重松节油制备高软化点萜烯酚醛树脂

采用下列苯酚对甲醛的分子比,松节油进行烷基化为１：０．８０－０．８８,重松节油进行烷基化为１：０．７５－０．８２时,能获得较高聚合度的母体酚醛树脂。该树脂烷基化之后于－０．０９５ＭＰａ表压下加热至≤３００℃脱除低分子物,可得软化点最高为１６０℃左右的萜烯酚醛树脂。其软化点比母体酚醛树脂增高的原因主要是烷基化使树脂分子量增高的结果。     

萜烯-邻苯二酚树脂的合成及性能研究

以CuCl2为催化剂，松节油、邻苯二酚为原料合成了萜烯-邻苯二酚树脂（简称TCR），对产物进行了红外、紫外光谱分析以及分子质量测定，考察了反应条件对实验结果的影响，并初步探讨了聚合反应产物的性能。结果表明，在CuCl2催化剂的作用下，邻苯二酚与萜烯发生聚合反应，产物TCR的数均分子质量为536，它易溶于有机溶剂，与萜烯酚树脂和萜烯树脂相比，具有良好的成膜性能；本实验较佳的反应条件为：n（萜烯） /n（邻苯二酚）为3：1，催化剂用量为反应物质量的4.59%，温度为158℃，反应时间24h。     

萜烯酚醛树脂新的合成法

萜烯酚醛树脂新的合成工艺。通过实验室试验,确定了较为理想的lewis酸催化剂体系,并确定了较佳的工艺条件。以水为介质,催化剂用量为1.5～1.8%,使酚、醛、萜烯的摩尔比为1∶0.7～0.8∶1.3～1.6之间,在95～210℃下进行缩合、烃化反应,反应时间330～360分钟,反应结束后蒸馏出少量未反应组份,可得到淡黄至黄色树脂,固体树脂得率≥90%,(按理论产量计算),树脂的软化点≥80℃。     

萜烯酚树脂溴值测定方法的研究

通过大量的实验探讨了影响萜烯酚树脂溴值测定的主要因素，论述了样品的称样量、溴酸钾－溴化钾溶液的加入量静置时间等与样品溴值之间的关系，确定了萜烯酚树脂溴值测定的适宜操作方法。     

萜烯－马来酸酐不饱和聚酯树脂的合成及其性能研究

以优级松节油为原料，合成萜烯－马来酸酐加成物（简称ＴＭ）．再以ＴＭ、马来酸酐、二元醇等为基料，合成了几种不饱和聚酯树脂（ＴＭ－ＵＰ树脂）．讨论了不同配方及合成工艺与树脂产品性能的关系，并对其物化性能、树脂浇铸体力学性能及耐腐蚀性能等进行了测试，从中选出了几种综合性能较好、工艺较简单、成本较低的ＴＭＡ－ＵＰ树脂配方．通过比较得知制得的ＴＭ－ＵＰ树脂性能达到或超过通用型商品ＵＰ树脂，完全可代替通用型商品ＵＰ树脂应用．     

萜烯邻苯二酚树脂-生漆共聚涂料研究(Ⅱ)--萜烯邻苯二酚树脂-生漆共聚涂料的合成及性能研究

以萜烯树脂、邻苯二酚为基本原料,在催化荆作用下合成萜烯邻苯二酚树脂;再将此树脂与生漆通过聚合反应生成萜烯邻苯二酚树脂-生漆共聚涂料,探讨了制备萜烯邻苯二酚树脂-生漆共聚涂料的工艺条件及各种性能,并测定了催化剂对共聚涂料膜性能的影响。实验结果表明,加入催化荆后缩短了萜烯邻苯二酚树脂-生漆共聚涂料的干燥时间,最佳条件下,反应时间可缩短3h．干燥时间可缩短24h,并改进了该涂料的膜附着力、硬度、厚度和耐汽油性等性能。讨论了萜烯邻苯二酚树脂与生漆的不同质量比和不同反应时间对此共聚涂料性能的影响,并进行了紫外光谱分析测试,结果表明生漆中的邻苯二酚和萜烯邻苯二酚树脂中的邻苯二酚都参与了聚合反应。得到最佳漆膜的条件为,用汽油作溶剂,按萜烯邻苯二酚树脂与生漆的质量比1：4,加入总溶质l％(质量分数)的催化荆,室温反应5．5h,涂膜后干燥3d。     

新型高效燃油

该燃油为内燃型汽、柴油机组内，外燃油型锅炉行业所用燃油提供高效增标、催化、洁净、抗磨、增氧的产品。具体配方如下： 硫酸亚铁０．０５％～２，６％，苦味酸０．８％～８．１％，硫酸铜０．０１％～１％，尿素０．０１％～０．１％，硝酸甘油０．０１％～２．１％，十二胺０％～０．９％，苯油０％～６％ＨＯＣＨ２ＣＨ２ＯＨ ０％～０．８％，聚四氟乙烯０．１％～０．９％石墨０．０１％～１．２％，硝基苯０％～１．２％，醋酸０．０１％～１．６％，ＣＨ３ＯＨ ０．１％～６０％，（ＣＨ２）ＣＨＯＨ０．０８％。０．９％，（Ｃ５…     

固体超强酸催化合成松油醇的研究

将ＳＯ４＾２－／ＳｎＯ２固体超强酸用于催化合成松油醇，显示出很高的催化活性；获得了ＳＯ４＾２－／ＳｎＯ２制备及松油醇合成的较好工艺条件：硫酸浓度为１．０ｍｏｌ／Ｌ，焙烧温度５５０℃，焙烧时间３ｈ，催化剂用量为松节油重量的８％，一氯乙酸与松节油的摩尔比为１．０￣１．４：１，反应温度６０℃，反应时间８￣１２ｈ。ＳＯ４＾２－／ＳｎＯ２还具有良好的重复使用性能和再生效果。     

酚醛树脂与木材之间的相互作用

按不同的（甲配合）Ｆ／／Ｐ（苯酚）摩尔比（１．７０，２．００和２．３０）及ＮａＯＨ／Ｐ的摩尔比（０．４和０．６０）合成了一系列甲阶酚醛树脂。用粘度、密度、分子量、表面张力和接触角表征，采用第配方合成的宽分子量分布的酚醛树脂（ＰＦ）的特性。关于合成配方及树脂特性的变化，通过测定树脂的表面特性、湿润性及木材的表面特性的改变来表示。研究结果认为，甲阶ＰＦ胶的表面张力随ＮａＯＨ、甲醛数量及分子量而变化，毛     

萜烯苯乙烯树脂溴值的测定

本文研究了萜烯苯乙烯树脂溴值的测定方法，论述了溶剂加入量、样品称量、溴酸钾—溴化钾溶液加入量、静置时间等对测定结果的影响，确定了萜烯苯乙烯树脂溴值测定的适宜操作条件。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

Modelling of adequate pretwist for obtaining straight timber

Abstract

Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists.