倍花提取物碱法水解制取没食子酸的研究

研究了倍花提取物碱法水解制备没食子酸的工艺条件，重点叙述了水解温度，碱用量及活性炭用量对没食子酸产品收率及颜色指标的影响，并确定了最佳工艺条件。     

碳酸二甲酯作甲基化试剂合成丁香酚甲醚

以绿色化学原料碳酸二甲酯(DMC)代替传统有毒有害试剂作为甲基化试剂,以丁香酚为原料,在固体碱K2CO3催化作用下合成丁香酚甲醚.对几种不同催化剂进行筛选,确定K2CO3为催化剂;以丁香酚甲醚得率为评价指标,采用中心复合设计法对丁香酚和DMC甲基化反应的工艺进行优化,得到制备丁香酚甲醚的最佳工艺:反应温度155℃,K2CO3用量6.12％(占丁香酚的摩尔分数),n(DMC)∶n(丁香酚)4.3∶1,反应时间6h,在此条件下丁香酚甲醚得率的预测值为96.44％.对最佳工艺进行验证实验,丁香酚甲醚得率为96.16％,表明中心复合设计预测性良好,实验重复性好.采用气质联用、红外光谱对产物进行分析.     

二氧化锰氧化茴脑制备茴香醛的工艺研究

以茴脑为原料,硬锰粉为氧化剂,在硫酸介质中制备茴香醛.考察了投料比、滴加的硫酸的质量分数、反应温度、水用量对转化率的影响,确定了最佳工艺条件:反应温度100～105℃,投料比为n(茴脑)∶n(二氧化锰)∶n(硫酸)1∶4∶4,硫酸质量分数为30%,水用量为硬锰粉质量的3倍,反应时间2.5h,转化率达99%,产品收率62.11%.在该优化条件下,将茴脑的投料量扩大10倍,转化率仍可达97.59%,产品收率61.53%.     

固体超强酸催化长叶烯制备异长叶烯的研究

研究了SO2-4/TiO2-ZrO2型固体超强酸催化剂的制备及其催化长叶烯的异构反应,通过GC、GC-MS和标样分析,确定其主产物为异长叶烯.结果表明,该催化剂对长叶烯的异构化反应有很高的催化活性和较好的选择性.考察了其催化性能的影响因素.结果表明,适宜的催化剂制备条件是:n(钛)∶n(锆)为3∶1,焙烧温度550 ℃.长叶烯异构优化的工艺条件:反应时间4 h、反应温度165 ℃、催化剂用量4 %.该条件下长叶烯转化率99.1 %,异长叶烯得率97.2 %.同时考察了催化剂放置时间对异构产物的影响和催化剂重复使用情况.     

天然苯甲醛合成新工艺

实验利用丙二醇做溶剂,NaHCO_3为催化剂,研究肉桂醛水解制苯甲醛的工艺条件。通过单因素试验和正交试验得出反应温度、催化剂用量、H_2O_2的用量和反应时间对得率有显著影响,最佳条件:反应时间2.5 h,反应温度60℃,肉桂醛和NaHCO_3的摩尔比1∶0.15,肉桂醛和H_2O_2的质量比1∶20。苯甲醛平均得率81.85%。     

甲酸水解纤维素制取纤维低聚糖的研究

研究了盐酸催化下甲酸水解生物质纤维制取纤维低聚糖的过程,探讨了时间与温度对水解的影响,并对工艺条件进行优化.实验表明,随着反应时间增加,棉花结晶度随之减少并不断水解;水解的最佳工艺条件为:1g棉花、24g含4%(质量分数)盐酸的甲酸溶液在65℃下水解8h,总还原糖得率25.06%,葡萄糖得率16.71%,纤维低聚糖得率8.35%.     

芦苇浆纳米纤维素的制备工艺条件优化及形貌分析

采用硫酸水解芦苇浆制备纳米纤维素,并用正交试验优化了工艺参数,分析了硫酸质量分数、反应温度和水解时间对芦苇浆制备纳米纤维素得率的影响.用透射电镜表征了芦苇浆制备的纳米纤维素的形貌.结果表明硫酸水解芦苇浆制备纳米纤维素的3个工艺参数对其得率的影响为硫酸质量分数的影响最大,反应温度的影响次之,而水解时间的影响较小;硫酸水解芦苇浆制备纳米纤维素的优化工艺条件为硫酸质量分数52％,反应温度47℃,水解时间4h,此条件下纳米纤维素得率最高(82.81％).芦苇浆制备的纳米纤维素经透射电镜观察呈棒状,纤维素长度达到纳米级.     

-蒎烯合成3-亚甲基诺蒎酮的研究

研究了以β-蒎烯为原料合成3-亚甲基诺蒎酮的反应.以丙酮为溶剂,以酸性高锰酸钾为氧化剂,β-蒎烯经选择性氧化生成诺蒎酮,研究了氧化剂体系、溶剂体系、反应温度和反应时间对β-蒎烯氧化选择性及诺蒎酮得率的影响.采用KOH为催化剂、37％甲醛水溶液为羟甲基化试剂与诺蒎酮进行羟醛缩合反应得到3-亚甲基诺蒎酮,探讨了诺蒎酮与甲醛物质的量之比、催化剂种类及用量、溶剂体系、反应温度以及反应时间等因素对反应的影响,并采用正交试验法优化了羟醛缩合反应工艺,并确定了适宜的合成工艺条件:n(甲醛)与n(诺蒎酮)为21∶1,n(KOH)与n(诺蒎酮)为1.5∶1,反应在无溶剂存在下进行,反应温度65 qc,反应时间2h.在此工艺条件下,3-亚甲基诺蒎酮得率大于92％.采用GC-MS、FT-IR、1H NMR、13C NMR等手段对合成所得产物的化学结构进行了分析测定.     

二元端乙烯基型松香衍生物的微波辅助制备及表征

以丙烯酸改性松香酸钠和氯丙烯为原料,十六烷基三甲基溴化铵为催化剂,对苯二酚为阻聚剂(用量为丙烯酸改性松香钠质量的0.2%),N,N-二甲基甲酰胺为溶剂(用量为丙烯酸改性松香钠质量的3倍),在微波辅助条件下,探讨了工艺条件对二元端乙烯基型松香衍生物丙烯酸改性松香烯丙酯得率的影响,确定了最佳工艺条件为:微波功率400 W,反应时间100 min,催化剂用量4%,物料配比n(氯丙烯)∶n(丙烯酸改性松香钠)2∶1,反应温度50℃,在此条件下产物得率高达92.2%。采用GC、GC-MS和FT-IR等技术表征了反应产物的结构,结果表明合成产物结构与目标产物结构一致。     

Synthesis of 2,3,4,4'-tetrahydroxybenzophenone via Hoesch Reaction

提出了一种新颖的合成2,3,4,4-四羟基二苯甲酮的方法.以焦性没食子酸和对羟基苯甲腈为原料,于无水乙醚中在氯化氢和Lewis酸ZnCl2存在下发生Hoesch反应,经后处理得到2,3,4.4-四羟基二苯甲酮.通过正交试验对影响反应的因素进行了考察,确定了最优工艺条件:焦性没食子酸与对羟基苯甲腈的物质的量比为1∶0.96,催化剂54.4 g(相对于1 mol焦性没食子酸),反应温度20℃,反应时间24h.在此条件下产品得率达90％以上,产品纯度在98％以上.     

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.     

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。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.