微波辐照提取板栗壳棕色素的研究

以板栗壳为原料,在微波条件下,以乙醇溶液作溶剂直接从板栗壳中提取天然棕色素.探讨了各因素对板栗壳天然色素提取效果的影响.确定了在微波条件下从板栗壳中提取天然色素的最佳工艺条件:5 g板栗壳粉在微波辐照时间13 min、浸提温度75 ℃、乙醇溶液的体积分数40 %、料液比1:20(g:mL)的条件下得率为7.02%.通过对色素的定性实验和稳定性实验,表明该板栗壳色素属于黄酮类色素,其对光照、温度、还原剂、氧化剂、pH值有良好的稳定性.     

响应面法对板栗壳色素的超声辅助提取工艺优化研究

以NH4OH水溶液为溶剂,采用响应面法对超声波辅助提取板栗壳色素的工艺条件进行了优化。采用中心复合实验设计,进行了不同NH4OH浓度、液料比和浸提时间对色素粗提物得率和色价影响的响应面分析实验。结果表明,所得二次回归模型对实验数据有较好的拟合效果;以色素粗提物得率为考察指标的优化提取条件为,NH4OH浓度为1.1 mol/L,液料比为16.5 mL/g,提取时间为120 min;以色价为考察指标优化提取条件为,NH4OH浓度为0.7 mol/L,液料比为14.6 mL/g,提取时间为112 min。板栗壳色素在生产中采用以色价为考察指标的优化提取工艺为宜。     

应用微波技术提取紫荆花色素的研究

研究了应用微波技术从植物紫荆(Cercis chinensis Bunge)的花中提取色素的新工艺并确定了最佳工艺条件：原料0．2000g紫荆干花，提取剂95％乙醇，料液比1：50(g：mL)，微波功率648w，提取时间30s，提取次数2次。最佳工艺条件下色素的提取率为92．1％，产率为9．48％，色价E(1％，549nm)为22．3。与溶剂浸提法相比，微波法提取紫荆花色素的每次提取时间由24h减小为30s，提取率从90．2％增加到92．1％。     

石斛兰色素的提取及稳定性研究

对石斛兰色素提取的最佳方法以及稳定性的研究结果表明：石斛兰色素的最大吸收波长为545nm;提取最佳条件组合为：提取温度50℃,提取时间2h,提取浓度50%乙醇溶液,料液比为1∶5;色素在pH值为4左右较稳定,碳水化合物对色素有保护作用,金属离子Fe2＋、有机酸、氧化剂H2O2和还原剂Na2SO3均对色素有破坏作用。     

板栗壳中多酚的提取及体外抗氧化性研究

研究了不同因素对板栗壳多酚提取效果的影响,并对不同条件下板栗壳多酚的抗氧化性进行了研究。结果表明,板栗壳多酚的最佳提取条件为:乙醇体积分数59.7%,料液比1∶18(g∶mL),浸提温度52.6℃,浸提次数3次。在此最优工艺条件下板栗壳多酚提取得率预测值为76.0 mg/g,实验值75.9 mg/g。板栗壳多酚具有较强的清除自由基能力,在25~200 mg/L范围内,随质量浓度升高其还原能力和清除二苯基苦基肼自由基(DPPH.)、羟基自由基(.OH)、超氧阴离子自由基(O-2.)的能力逐渐增强,当200 mg/L时其还原能力达0.841,DPPH.抑制率达89.7%,均高于同质量浓度的2,6二-叔丁基对甲酚(BHT),但低于同质量浓度Vc,对O-2.和.OH的清除率分别为93.2%和94.0%,均高于同质量浓度BHT和Vc。     

真丝织物板栗壳媒染工艺的优化与蜡染产品的开发

以天然板栗壳色素为染料,选用硫酸铝钾、硫酸亚铁、硫酸铜和壳聚糖4种媒染剂,对真丝织物进行媒染染色,测量染色试样的K/S值、⊿E值、摩擦牢度和耐洗牢度,确定硫酸亚铁为最佳媒染剂。通过正交实验分析,确定了板栗壳染料用于真丝织物媒染染色的最佳工艺条件,并利用该方法开发了板栗壳染料蜡染产品。结果表明:板栗壳染料适合于真丝织物的染色。     

萃取法提取洋葱中类黄酮的研究

以市售鲜洋葱为原料，乙醇为萃取溶剂，对洋葱中的类黄酮进行提取，分别探讨了提取时间、提取温度和固液比3个单因素条件对洋葱中类黄酮提取率的影响，并结合单因素实验结果进行了正交实验，以此得出了最佳提取条件。实验结果表明：乙醇的体积分数为95％时，洋葱中黄酮类化合物的最佳提取条件为：提取时间4h ，固液比为1∶1．5（g/mL ），提取温度为40℃，在此条件下洋葱中黄酮类化合物的提取率为0.0137％。     

红地球葡萄皮色素的提取及其稳定性的影响因素

以新鲜红地球葡萄为原料,探讨其天然色素的提取工艺,并通过正交实验得出了红地球葡萄色素的最佳提取工艺条件:80%的乙醇作提取剂,pH值为3,提取温度为70℃,料液比为1∶9。并对红地球葡萄色素的稳定性进行了研究,结果表明:红地球葡萄色素在pH为2~6时相对稳定,耐热性较好,耐光性也较好;金属离子对色素稳定性有一定的影响,其中Cu2 、Fe3 、Fe2 对色素的色泽有较大的破坏作用,但M g2 对红地球葡萄色素有稳定作用;氧化剂H2O2和还原剂N a2SO4对色素有一定的破坏作用。     

超声波提取大花葵色素的工艺研究

大花葵(Malva sylvestris L.var.mauritiana Miller)为锦葵科锦葵属一年生草本植物，结花量大，花中含有大量的红色素，是一种重要的天然色素资源，可广泛应用于食品、制药、化妆品等行业。大花葵色素属于花青苷类色素，常规提取工艺容易使其发生降解、褪色。超声波提取技术具有时间短、效率高、提取量高等特点，同时可防止提取物在长时间、高温条件下发生降解、褪色等变化。作者对超声波提取大花葵色素的各项工艺条件进行了初步探讨，设计了工艺流程，研究了超声波提取的温度、时间和提取剂对色素提取率的影响，得出最佳提取工艺参数为：在超声波频率为30kHz条件下，用质量分数为2％的稀H2SO4作提取剂，处理40min，温度50℃时提取率最高。     

橡子壳色素的研究

报道了从橡子壳中提取、分离天然色素的方法，分析其化学结构，研究其结构的稳定性和毒性。     

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.     

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.     

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.     

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。     

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.