家具用重组竹干缩与湿胀性能研究

重组竹是一种新型的可替代硬阔叶材的结构材.对重组竹用于家具制造的干缩与湿胀性进行了研究,结果表明:重组竹的干缩湿胀率均表现出很强的方向性,表现为宽度最大,厚度次之,纵向最小.重组竹出厂时应标明热压时的压制方向,以利用于家具用材加工时进行各方向上加工余量的确定.重组竹干缩系数与柚木相近.在相同近密度下,比几种常见家具木材麻栎等的干缩系数要小,这表明重组竹适于用作家具制造用材.     

重组竹材料技术创新与面临的关键问题

重组竹是将竹材重新组织并加以强化成型的一种竹质新材料，是中国拥有自主知识产权、并已实现产业化利用的一种竹基复合材料，具有原材料利用率高、力学性能优异的特点，产品可应用于室内外地板、家具、建筑结构材、装修装潢材，以及风电桨叶等高强度材料领域。目前，中国在重组竹制造技术领域取得重要进展，但也面临着许多制约产品开发与应用的基础研究障碍，亟待解决。文章总结了重组竹材料技术研究取得的重要进展，分析了重组竹材料在产品开发利用中尚需解决的技术问题，以期为高性能重组竹材料的理论研究和实践提供参考。     

重组竹新中式家具的装饰工艺研究

重组竹作为家具制造的基材,在木材资源不断减少的今天具有节约资源,绿色环保的优势,并可以作为新中式家具的制作材料来替代传统硬木。但是重组竹在材色和纹理上缺乏传统硬木所具备的视觉美感,因此对重组竹新中式家具的装饰就显得尤为重要,本文从重组竹新中式家具的雕刻、涂饰、镶嵌三个比较主要的装饰工艺方法进行分析和研究,拟得出适合重组竹新中式家具材料特点和造型特点的装饰方法。     

小径木重组材与家具设计的关联性研究

小径木重组材是一种先进生物质材料,在家具、地板制造和室内外用材等方面具有较好的应用前景。为了研究小径木重组材与家具设计之间的关联性,探明小径木重组材应用于家具设计的具体适应性,文章综合运用比较分析法、功能分析法、调查法等科学研究方法,在概述小径木重组材的制造工艺和应用范围的基础上,从家具设计的形式设计、功能设计、情感设计和绿色设计4个方面,结合小径木重组材的材料特性和家具设计过程中对于材料的表现要求,对比了小径木重组材在软硬、轻重、冷暖等感觉性能及肌理、色彩、光泽等表面性能与天然木材的异同,分析了小径木重组材的机械加工性能和功能改性对于家具功能的增益,描述了小径木重组材培养型和寓物型情感特征的由来,调查了小径木重组材在产品生命周期评价体系中与定向刨花板、中密度纤维板相比能源消耗的增减。最终验证了小径木重组材应用于家具设计与制造的合理性和优胜性,侧面反映了家具制造对于小径木重组材制材的改性要求,为利用小径木重组材进行家具设计提出了参考要素,为拓宽木质家具用材渠道同时实现小径木重组材高值化利用的双赢问题提供了理论依据。     

弧形原态重组竹茶艺家具设计

以按弧形状态叠加胶合而成的弧形原态重组竹为基材,在了解与掌握材性的基础上,通过深入分析与总结其在形态、色彩、肌理等方面的设计表现力,探讨弧形原态重组竹在茶艺家具设计中的应用。通过采用简约大方的造型、自然天成的色彩、变化丰富的图案与肌理,以新中式风格为特征,结合茶艺家具的特点,设计弧形原态重组竹茶艺家具。为弧形原态重组竹在家具中的应用提供一个新的思路。     

“户外重组竹材”行标起草预备会在杭召开

重组竹是以竹材为原料而加工的人造板产品，可广泛用作建筑模板、车厢底板、装饰材料、包装材料、家具用材、地板等，不仅可用于室内，也可用于户外。据了解，2007年全国重组竹材产量达800万m^2，生产企业有近50家，其中生产户外重组竹材的企业有6家。     

重组竹发展前景展望

重组竹是90年代开始研究的新产品。它竹材利用率高；物理力学性能优良；加工性能好；外表美观；工艺简单；且成本低廉，是很有发展潜力的新产品。可用作工程结构材料、装饰材料、家具用材、地板等，经过模压可作各种特殊用途。本文介绍了重组竹研究的起源，阐述了重组竹的研究现状，并且从资源、技术、经济效益三方面分析了重组竹在我国发展的可行性，预测了重组竹的发展前景。     

降压工艺对竹重组材性能的影响

对竹重组材的热压工艺进行研究,分析了板材降压时间、排湿时间、降压压力、出板温度等工艺因素对板材的静曲强度、弹性模量、吸水厚度膨胀率等性能的影响,探讨竹重组材热压的较佳工艺参数。试验结果表明:竹重组材采用"V"型的降压方式,可以提高板材的质量,缩短热压周期,提高生产效率。竹重组材较佳工艺条件为降压时间23 min,排湿时间60 s,降压压力1.0 MPa,出板温度70℃。     

基于毛竹材的竹重组材关键技术研究

以毛竹为实验材料,研究了竹重组材在生产过程中冷压工艺和热压工艺的关键技术参数对竹重组材性能的影响。结果表明:1)采用冷压工艺时,用胶量对产品的胶合强度和膨胀率影响明显,用胶量为10%时生产的竹重组材具有较好胶合强度和吸水膨胀性能;竹束含水率为12%时其产品力学强度最好;竹重组材的密度越高,其各项性能指标就越好;加热温度为135℃时,产品的各项性能最佳;加热时间选择15 h较为合适。2)采用热压工艺时,较优热压工艺条件为单位压力2.0 MPa、热压温度145℃、热压时间1.7 min/mm;此工艺流程大大提高了生产效率,降低了生产能耗。     

改性酚醛树脂制备及对竹重组材防白蚁效果初步研究

为改善竹重组材防白蚁效果,研究分别在酚醛树脂合成前端和后端加入硼化物,制备竹重组材用改性酚醛树脂,并对改性酚醛树脂压制的板材进行性能测试。研究结果表明：改性酚醛树脂可将竹重组材抗白蚁等级从 8 级提高至 9 级以上;前端改性酚醛树脂压制的竹重组材抗白蚁效果和物理力学性能均优于后端改性酚醛树脂。     

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。     

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.     

Key Habitats in the Norwegian Production Forest: A Case Study

This study investigated the forest history, structural characteristics, the presence of fungal species suggested to indicate ecological continuity in old-growth forest, and the species composition of saproxylic beetles in 30 old forest ''woodland key habitats'' (WKHs), and compared them with production forest in the same age-class in south-eastern Norway. No statistically significant differences in forest characteristics, community of saproxylic beetles or number of red-listed beetles were found between the WKHs and the production forest, probably owing to a combination of profound long-term logging and a lack of will to delineate sufficiently large WKHs in the one area with significantly less forestry impact. The study indicates the advantage of including forest history information in WKH selection where such data exist, and the importance of restoring habitats in heavily exploited forest landscapes.