虫白蜡制备高级烷醇混合物研究

通过虫白蜡皂化法制备高级烷醇混合物探索研究,得到虫白蜡制备高级烷醇混合物的工艺优化条件:10 g虫白蜡皂化加碱4 g,皂化温度90 ℃,皂化时间10 h,氯化钙加入量为碱物质的量的一半,在80 ℃条件下,保温搅拌2 h后,抽滤,滤饼烘干,用乙醇为抽提剂,然后再用乙醇-丙酮混合溶剂将高级烷醇粗品重结晶3次,结晶体在70 ℃左右干燥,可得到纯度为93%的高级烷醇混合物.     

虫白蜡还原法制备高级烷醇混合物研究

通过虫白蜡还原法制备高级烷醇混合物探索研究,得到虫白蜡制备高级烷醇混合物的工艺优化条件:10 g虫白蜡还原制备高级烷醇,氢化铝锂用量0.7 g,四氢呋喃溶剂用量70 mL,在65℃、常压和超声波作用条件下,进行还原反应5 h后,用水煮沸洗涤2~3次,过滤,滤饼烘干,虫白蜡转化率可达到95%~98%。用有机溶剂重结晶高级烷醇混合物后,用气相色谱测定组成为二十六烷醇56%、二十八烷醇32%、二十四烷醇5.2%、三十烷醇4.0%、二十五烷醇1.5%、二十七烷醇0.9%。     

茄尼醇的纯化工艺研究

以茄尼醇粗品为原料,利用皂化柱层析法进行纯化。对皂化工艺参数进行了正交试验优化,得到皂化最佳工艺参数为:茄尼醇粗品50 g,乙醇用量250 mL,20%氢氧化钠溶液20 mL,在80℃下反应3 h。柱层析以6#溶剂油-乙酸乙酯(体积比10∶1)洗脱,得到的产品收率达到14%,纯度达95.8%。     

交联魔芋葡甘聚糖微球的制备与表征

用正交设计的方法对交联魔芋葡甘聚糖球(CKGG)的制备条件进行研究，确定了在30％乙醇水溶液中碱用量与魔芋摩尔比1：2，环氧氯丙烷用量与魔芋摩尔比1：1，温度45℃，反应时间6h制得的CKGG具有较好的交换容量。该种颗粒为蜂窝状多孔微球，色泽好，粒度均匀，阳离子交换容量为0．2114mmol／g，不溶于水、酸和碱。     

蒎烷空气氧化反应的研究

研究了蒎烷的氧化反应，实现了用空气代替纯氧气进行氧化以制备蒎烷氢过氧化物（PHP）的设想。蒎烷的空气氧化反应需要用催化剂；反应时间约在25h左右，比用纯氧氧化延长了3-5h；反应温度一般控制在110℃以内，与纯氧氧化温度类似。在空气氧化蒎烷得到的产物中，PHP含量一般可达45%-50%，与用纯氧氧化的结果相当。氧化产物进行常压催化加氢所得还原产物粗蒎醇用GC分析的结果表明，其蒎醇含量（超过38%）及主要产物组成与用纯氧氧化所得产物基本一致。在回收蒎烷中含较多反式蒎烷。实验结果表明，空气氧化工艺有可能代替纯氧氧化工艺应用于合成PHP的工业生产。     

白蜡及白蜡高级烷醇对人真皮乳头细胞生长的影响

[目的]明确白蜡及白蜡高级烷醇吐温水溶液对人真皮乳头细胞(HFDPCs)生长的影响。[方法]采用台盼蓝法测定细胞的的接种数量,接种第2天给药,给药48 h后采用MTS法研究不同浓度吐温80、白蜡及白蜡高级烷醇吐温水溶液对人真皮乳头细胞的作用。[结果]人真皮乳头细胞在吐温80用量1.56 6.25μg·m L~(-1)范围内能正常生长。在安全范围内,白蜡(增溶量为0.31 1.25μg·m L~(-1))吐温水溶液、白蜡高级烷醇(增溶量为3.12 12.5μg·m L~(-1))吐温水溶液均能促进人真皮乳头细胞的增殖,其中,水溶液中含有6.25μg·m L~(-1)吐温80和1.25μg·m L~(-1)白蜡、水溶液中含有6.25μg·m L~(-1)吐温80和12.5μg·m L~(-1)白蜡高级烷醇时细胞的增殖率明显高于非那雄胺。[结论]吐温80作为增溶剂,其用量低于6.25μg·m L~(-1)时对人真皮乳头细胞安全。在保证吐温80对细胞安全的条件下,白蜡及白蜡高级烷醇可显著促进人真皮乳头细胞的增殖。     

万寿菊花中叶黄素提取及分离提纯的研究

研究了利用正己烷和乙醇混合溶剂,或石油醚溶剂,从万寿菊花粉提取、分离、提纯叶黄素的方法.最适工艺参数:正己烷(为提取剂)和95%乙醇(体积比3:2),提取温度60℃,提取时间4～5h,提取次数5～6次,液料比15:1(mL:g);皂化温度55～60℃,皂化时间6h.按本工艺条件操作,万寿菊花中叶黄素得率为7.5%～7.9%.     

β—蒎烯合成紫苏醇的研究

研究β－蒎烯制备紫苏醇过程中的各种影响因素。探讨了β－蒎烯的四醋酸铅氧化，异构，皂化等合成紫苏醇的工艺条件及产品质量分析，结果表明，投料比：β－蒎烯：四氧化三铅：冰醋酸为１：１：１６，温度为６０±２℃时氧化１ｈ；１６０－１７０℃异构１０－１２ｈ；７８℃皂化１ｈ，可得纯度为８４．５％的紫苏醇。产品质量与国外相比基本一致。为紫苏醇产品的工业化提供了依据。     

从稻壳中提取木聚糖的研究

以稻壳为原料，采用制备综纤维素再碱提取的方法，分析了不同碱溶液浓度、温度、固液比和时间对稻壳半纤维素中多戊糖得率的影响。实验结果表明，稻壳中多戊糖含量为19.9％，是较好的木聚糖资源。碱提取稻壳中木聚糖的方法为：预处理：80℃水浸泡3h：碱提取条件：碱质量分数10％，固液比（g：mL）1：10，提取时间3h，提取温度80℃。木聚糖提取率达原料中木聚糖总量的67．50％以上。     

β－蒎烯合成紫苏醇的研究

研究β－蒎烯制备紫苏醇过程中的各种影响因素。探讨了β－蒎烯的四醋酸铅氧化、异构、皂化等合成紫苏醇的工艺条件及产品质量分析，结果表明，投料比：β－蒎烯：四氧化三铅：冰醋酸为１：１：１６、温度为６０士２℃时氧化１ｈ；１６０～１７０℃异构１０～１２ｈ；７８℃皂化１ｈ，可得纯度为８４．５％的紫苏醇。产品质量与国外相比基本一致。为紫苏醇产品的工业化提供了依据。     

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.     

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.     

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.     

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。     

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.