对伞花烃直接电解氧化反应的评价

研究了在有机溶剂、合适的支持电解质和碳棒存在下，对伞花烃的直接电解氧化反应，使用GC和GC-MS方法分析测定了主要电解氧化产物，如：百里香酚甲醚、1-异丙基-4-甲氧甲基苯、枯茗醛、枯茗醇、对二甲氧甲基异丙基苯、枯茗酸甲酯、对羟基甲氧甲基异丙基苯、乙酸枯茗酯和1-二甲氧甲基-4-(1-甲氧基-1-甲基乙基)苯。详细研究了影响氧化主产物得率的主要因素，对伞花烃直接电解氧化选择性地制备枯茗醛合理的电解条件为：电解时间20-25h，甲醇／乙酸体积比10：1，氟硼酸钠作支持电解质，阳极／阴极面积比1：1，电流密度0．018A／cm^2。     

3-蒈烯催化转化反应及应用研究

以建立3-蒈烯的高效利用途径为目的,对其催化转化进行了深入研究,结果表明:金属类催化剂对促进3-蒈烯发生三元环开环脱氢具有很高的活性,尤其是在铂催化下脱氢产物伞花烃的选择性超过90%,其中,间伞花烃与对伞花烃的质量比约为7∶2;分子筛催化同样会导致3-蒈烯发生三元环开环并脱氢,随着反应温度升高,脱氢产物对伞花烃进一步裂解生成甲苯等芳烃化合物,ZSM-5型分子筛在促进裂解反应方面能力突出。在此基础上,建立了以金属铂与ZSM-5型分子筛为复合催化剂,3-蒈烯经连续催化转化制备甲苯与间伞花烃的工艺路线,在V(Pt/Al_2O_3)∶V(ZSM-5)1∶1,280℃的条件下,原料转化率接近100%,产品总得率大于85%,最终产物甲苯得率约25%,纯度大于99%;间伞花烃得率约46%,纯度大于95%。     

磺酸树脂对柠檬醛环化的催化作用及其动力学特征研究

以D-72磺酸树脂为催化剂催化柠檬醛环化反应,考查了反应介质、催化剂用量、反应温度和柠檬醛的体积分数对柠檬醛转化率和产物选择性的影响,探讨了环化反应的催化动力学特征。实验结果表明:环化反应产物为α-松油烯、对伞花烃、对异丙烯基甲苯;用四氯化碳为反应介质,对伞花烃的选择性为100%;0.8 g催化剂催化时柠檬醛的转化率为97.31%;用乙酸乙酯为反应介质,在柠檬醛体积分数为10%、催化剂0.4 g、反应时间1 h和343 K条件下反应时,柠檬醛的转化率和对伞花烃的选择性分别为97.76%和67.8%。动力学研究表明,柠檬醛在D-72催化剂上的环化反应服从一级动力学模型,经最小二乘法处理数据得表观活化能为60.7 kJ/mol。     

对伞花烃催化裂解反应及其产物成分分析

通过GC和GC-MS手段分析和鉴定了对伞花烃原料及其催化裂解产物（累计500h）的成分，从裂解产物中发现超过20种化合物，如：4-甲基丙苯、3-甲基-2-戊烯、2-甲基-2-已烯、邻伞花烃、间伞花烃、1，4-二甲苯、对Mong烷、1，2，4-三甲苯等，分析结果显示，裂解主产物甲苯和剩余原料对伞花烃的总相对含量约为90%，其它副产物的相对含量约为10%。并讨论了对伞花烃催化裂解反应过程。     

双戊烯合成对伞花烃的工艺研究

通过气相催化反应，使双戊烯合成对异丙基甲苯即对伞花烃，选择了适宜的催化剂，探讨了反应温度、催化剂活性组分浓度等因素对产物中对伞花烃含量的影响，并对催化剂的重复使用性能进行了考察，得出了适宜的工艺条件，在此条件下，产物中对伞花烃的含量为79.6%，通过精馏可得到高纯度（97.8%）的对伞花烃.     

对伞花烃氢过氧化反应及合成高纯对甲酚的研究

研究了以对伞花烃为原料液相氧化后再酸分解制备高纯对甲酚的合成工艺。对氢过氧化反应的影响因素进行了探讨,分析了反应的副产物,并对其进行了鉴定。通过研究表明,双对伞花粉为原料可合成含量在９９％以上的高纯对甲酚,得率为重量得率４０．０％,摩尔得率为４９．６％。     

木质素降解产物对纤维素酶和木聚糖酶水解的抑制

在稀酸等化学预处理过程中,木质素会降解生成酚类等产物进入后续糖化阶段,研究表明这些木质素降解产物会抑制木质纤维降解酶的水解效率,然而其抑制机制尚不清楚。笔者选择了3种典型的木质素降解产物:香草醛、4-羟基苯甲醛和丁香醛,考察了它们对商品纤维素酶和木聚糖酶,以及单一关键纤维素酶组分和β-木糖苷酶水解的影响,并探讨其抑制规律。实验结果表明,这3种木质素降解产物对纤维素酶和木聚糖酶的水解均有抑制,其抑制能力随降解产物浓度的增加而增强。当3种木质素降解产物的质量浓度为10 mg/m L时,纤维素酶水解微晶纤维素48 h的葡萄糖得率由71.17%分别减少到33.80%、29.52%和32.03%,说明这3种木质素降解产物对纤维素酶的抑制作用差异不明显。3种木质素降解产物对β-葡萄糖苷酶水解纤维二糖的效率没有影响,但是会强烈抑制外切葡聚糖酶CBH I的酶活。当木质素降解产物的质量浓度为2 mg/m L时,与未添加木质素降解产物的酶活相比,CBH I酶活分别降低至79.64%、86.76%和71.89%,抑制强弱顺序为:丁香醛香草醛4-羟基苯甲醛。此外,3种木质素降解产物对木聚糖酶和β-木糖苷酶的抑制强弱顺序均为:4-羟基苯甲醛香草醛丁香醛,当3种木质素降解产物的质量浓度为10 mg/m L时,木聚糖酶水解木聚糖48 h的木糖得率由57.28%分别减少到12.26%、20.16%和30.43%。抑制动力学试验表明,4-羟基苯甲醛对CBH I的抑制属于竞争性抑制,对β-木糖苷酶的抑制属于非竞争性抑制。     

美国《EI》收录本刊2005年第1—2期发表的文章题录

文章题目作者姓名年,(期):页EI登录号利用RAPD分子标记研究酵母菌的亲缘关系徐勇,等2005.25(1):1-4EIP05199092990对伞花烃及其裂解产物甲苯的间接电解氧化反应研究毕良武,等2005.25(1):5-9EIP05199092991胶原纤维固化杨梅单宁对Pb2+、Cd2+、Hg2+的吸附王茹,等2005.25(1):10-14EIP05199092992木二糖和木三糖的分离及其用于双歧杆菌的体外培养张军华,等2005.25(1):15-18EIP05199092993醇溶木质素溶胶流变特性的研究林海燕,等2005.25(1):19-22EIP05199092994色谱法测定制浆造纸工业漂白废液中的草酸浓度(英文)洪枫,等2005.25(1):23-…     

用磷钼酸催化合成马来海松酸反应的研究

以杂多酸磷钼酸为催化剂合成了马来海松酸.考察了催化剂用量、溶剂、反应时间及原料配比等对双烯加成反应的影响.实验结果表明,松香与马来酸酐摩尔比为1.7∶1,催化剂质量分数为2.0 %,甲苯作溶剂,反应时间4 h,反应得率可达78.9 %.     

响应面法优化羟基香茅醛1,2-丙二醇缩醛的合成

通过单因素试验,确定对目标产物产率影响最显著的3个因素分别为羟基香茅醛与1,2-丙二醇物质的量比、反应温度和反应时间。根据Central Composite Design试验设计原理,采用3因素3水平的响应面法,以目标产物产率为响应值,分析各个因素的显著性和交互作用,结果表明最佳合成条件为羟基香茅醛与1,2-丙二醇物质的量比为1∶3.5,反应温度为38℃,反应时间4.4 h,羟基香茅醛与甲苯物质的量比1∶2~1∶2.5,此条件下目标产物产率为89.76%。     

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.