刨切薄竹贴面刨花板加工工艺研究

以刨切薄竹为原料,通过正交试验,对刨切薄竹用于贴面刨花板的生产工艺进行研究.结果表明:当涂胶量135 g·m-2,热压压力为0.8 MPa,热压温度90℃,热压时间4.0 min时,刨切薄竹贴面刨花板的效果较佳,可用于指导生产实践.     

胶合板微薄木贴面生产工艺

本文简述了微薄木贴面应用于胶合板表面装饰的生产工艺。从木方准备,刨切薄木,直到薄木胶拼都有一定的工艺要求。厚度仅有0.25～0.3mm 的微薄木贴面在我国目前生产和使用的较少,其关键在于工艺和设备都尚不成熟,本文所述工艺亦不尽完善。虽如此作者仍将这一生产经验介绍给国内同行,抛砖引玉,博取多采,使其更趋完善。     

竹材刨切工艺的初步研究

毛竹经横截、去节、冲条、刨削等工序，加工成长条；再经干燥、涂胶、组坯、热压等工序，制成竹方；然后经高温水煮软化处理，在刨切机上进行横向热刨切，刨切成竹单板，用于高档贴面装饰，减少贵重木材的消耗。     

微薄木贴面装饰纤维板制造工艺初探

微薄木贴面装饰纤维板制造工艺初探娄四维（中南林学院湖南株洲４１２００６）微薄木贴面装饰人造板，是近年来流行的高档装饰材料，广泛应用于家具制造和室内装饰。应用最多的是用三合板作基材生产的微薄木贴面装饰胶合板（以下筒称装饰胶合板）。可是，胶合板价格较高，...     

刨切竹单板的软化工艺研究

为了克服刨切竹单板在家具曲面构件贴面或封边时出现横向开裂、破损等情况,采用氢氧化钠(Na OH)、碳酸氢钠(Na HCO_3)和尿素(CH_4N_2O)分别对刨切竹单板进行了软化处理。结果表明:刨切竹单板的软化工艺参数对其软化效果有较大影响,大小顺序为软化温度软化剂质量分数软化时间;随着软化温度的升高、软化时间的延长和软化剂质量分数的增大,刨切竹单板的横向柔韧性能逐渐增大;Na OH软化刨切竹单板的适宜工艺参数为:软化温度65℃、软化时间60 min、软化剂质量分数2%,Na HCO_3和CH_4N_2O则为:软化温度65℃、软化时间90 min、软化剂质量分数2%;其中,Na OH对刨切竹单板的软化效果最好。     

刨切薄竹贴面中密度纤维板工艺研究

对刨切薄竹贴面中密度纤维板(MDF)的工艺进行了研究,结果表明:在MDF的上下表面直接粘贴刨切薄竹的工艺可行,并根据试验结果确定了较优的贴面工艺参数.测试结果还显示,刨切薄竹背衬无纺布后再与MDF胶合,其表面胶合强度比刨切薄竹直接贴面MDF时低.     

覆膜厚帘竹胶合板模板的研制

研究了以3 mm以上厚度的竹篾片编织竹帘生产厚帘竹胶合板模板的工艺条件,讨论了热压时间、热压压力、热压温度及浸胶的胶液浓度对覆膜厚帘竹胶合板模板物理力学性能的影响,总结确定出最佳的可供生产应用的热压工艺条件.结果表明,在热压压力1.4 MPa、热压时间60 s/mm板厚、热压温度135 ℃、浸胶胶液浓度26%的条件下生产出的产品各项力学性能指标均达到或超出竹胶合板模板国家标准.     

彩色刨切薄竹生产关键技术

彩色薄竹是将水溶性染色剂在一定条件下,对刨切薄竹进行染色处理,使之具有所需均匀颜色的产品。染色是改善竹材视觉效果和提高竹材附加值的重要手段。本文根据国内外技术成果和作者的生产经验,对彩色刨切薄竹生产关键技术进行了总结,重点介绍了薄竹刨切主要生产工艺、薄竹染色关键处理技术和彩色薄竹复合加工工艺等,对彩色薄竹生产成本进行了分析。彩色薄竹是一种优良的装饰材料,可用于家具或人造板贴面,制造成各种装饰材料。     

泡桐制造单板和胶合板的研究

本报告为黄、淮、海地区三种泡桐制造单板和胶合板的研究。通过对单板旋切质量的测定,以及对胶合板胶合工艺、刨切薄木湿贴工艺的研究,得出结论如下: 1.泡桐材质轻软,缺陷较少,易于旋切和刨切,而且整幅单板出板率和一、二等面板率较高。2.采用泡桐和杨木混合组坯,井按特定的热压曲线进行胶合,既消除了纯泡桐结构胶合板卸压时易产生“鼓泡”,又改善了胶合板的胶合强度,提高了生产的经济效益。3.泡桐刨切薄木使用改性乳胶进行中温湿粘,胶层耐水性达到日本同类产品标;隹的要求。本研究为进一步发展泡桐单板和胶合板的生产提供了初步经验。     

枫香木材性质及其加工性能研究

采集浙江各地不同树龄枫香木材,系统研究木材解剖性质,主要物理力学性质,刨切、旋切等加工利用适应性等,结果表明:树龄20～25年是枫香木材物理力学性质的一个转折点,其主要物理性质和力学强度指标居国产阔叶树材中等水平;旋切单板胶合强度超过国家标准规定的技术要求,通过工艺改进后枫香材完全适合生产胶合板;刨切贴面板的刨切效果和贴面后的性能都较好,综合指标相对较高.     

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.