木工刨床的空转噪声及对人与环境的影响

本文从人一机一环境系统角度出发，以ＭＢ１０６Ａ型木工压刨床为例，通过对其空转噪声及机床操作者心率的实测，系统地研究了木工压刨床本身一些因素对木工压刨床空转噪声的影响；同时也研究了机床空转噪声与传播距离的关系；最后研究了木工压刨床噪声对机床操作者心率的影响。同时分析了噪声产生的机理，并进行了试验论证，最后建立了木工压刨床空转噪声的数学模型，从而为木工机床的研究与设计及人一机一环境系统工程的研究提供了依据。     

基于UG的木工铣刀CAD系统设计

以UG为支撑平台,利用Visual C 6.0、SQL Server和UG二次开发工具UG/Open研制开发了现代木工铣刀CAD系统.该系统界面友好,集现有木工铣刀查询、选型、设计计算和三维建模于一体,同时又具备良好的可扩展性和可移植性.实践证明该系统极大地提高了现代木工铣刀的设计效率和精度.     

数控木工机床的外观设计原则

数控木工机床是近几年木工及家具机械行业出现的新产品，代表了木工机械行业的发展趋势。为了使数控木工机床能够体现更先进、更人性化与环境更协调的现代化设计理念，本文就数控木工机床的外观设计原则做了必要的讨论。     

一种新型木工带锯机问世

日前，一种新型木工带锯机──MJ316台式木工带锯机在省林机厂问世。这是该厂科研人员为适应激烈的市场竞争和目前木材资源状况而研制出的一种新产品。投放市场以来，该机以其良好的使用性能，深受广大木材加工者的青睐，成为抢手货。这种新式木工带锯机是在原MJ318木工带锯机的基础上改进设计的。该机在整体设计、主要部件结构、技术参数和驱动控制等方面进行了大幅度的修改。在满足降低成本的前提下，尽量考虑技术先进、结构合理、操作调试简便，尽可能地提高银机的利用率。这种新型的木工带锯机可用于加工直径450毫米以内的圆木，制作…     

基于HNC-8的木工榫槽现场交互自动编程数控系统的开发

在分析木工榫槽加工特点的基础上设计了一种基于HNC-8（华中8型）平台面向专业木工榫槽加工的现场交互数控自动编程系统，其中的榫槽轮廓形状数据有两种输入方式：一种是采用直接读入标准的DXF文件格式，另一种是在用户界面上直接输入所需要的各种图元（诸如NURBS曲线、直线、圆弧、圆等构成的异形图元），然后系统根据工艺、加工参数快速生成加工代码直接进行加工。实际应用表明，系统工作可靠，能快速生成所需加工代码，提高了榫槽机的自动化程度。     

木工压刨床空运转振动状态的研究

木工压刨床空运转振动状态的研究李志仁，陈守谦，姜新波（东北林业大学哈尔滨１５００４０）关键词木工压刨床，振动状态，自功率谱，机内振源，刚度，动态设计木工压刨床是木材机械加工中使用数量最多，应用范围最广泛的一类机械设备，它不仅用于林业生产，而且在建筑、...     

木工榫槽铣刀的固有频率测试研究

分别采用随机激励功率谱和声学测量法测试木工榫槽铣刀的固有频率。结果表明，两种测试方法皆可行且安全可靠。对木工榫槽铣刀固有频率的测试研究可为木工榫槽铣刀设计与优化提供借鉴。     

一种钣金件结构的木工多用机床

介绍了一种用钢板设计制造的轻便型木工具用机床，它解决了现有的中，小型木工用机床重量大，制造成本高。主要大件不具有互换性及搬运不便等缺点，因该机床中７０％以上的零件均采用２．５～３ｍｍ冷轧板冲压成形制造，故机床制造简单，重量轻及互换性强，因此该结构的木工多用机床具有广阔的推广应用前景。     

我国木工跑车带锯自动摇尺型号与命名问题探讨

１　国内自动摇尺型号与命名概述我国木工机床的型号编制有专门的国家标准，归口到原机械工业部管理，而使用木工机床则主要在原林业部、物资部和轻工部等系统。我国定点厂生产的木工跑车带锯机按国家标准，都有完整的型号名称。例如，辽宁沈阳市带锯机床厂生产的ＭＪＢ３２１２型木工跑车带锯机；河南信阳木工机械厂生产的ＭＪＫ３２１２Ｃ数控跑车木工带锯机；四川岷江林业机械厂生产的ＭＪ（Ｚ）３２１０跑车木工带锯机；福建邵武木工机床厂生产的ＭＪ３２１０型跑车木工带锯机等。但构成跑车带锯的主要组成部分，号称带锯机心脏的自动摇…     

木工车床溜板箱的数控改造

对木工车床进行数控改造，不仅能提高生产率和加工件的尺寸一致性，而且能最大限度地发挥传统设备的作用。因此对上海木工机械厂生产的＊＊伽u。木工车床进行市数控改造。专门设计了四轴微机控制系统，并将原有的齿轮齿条传动装置改成丝杆螺母传动，实现了床面X、Z两轴和端面X’、Y’两轴的同时控制，使木工车床的加工效率提高了两倍。1车床结构的改进MCD616B木工车床溜板箱由0．37kw的交流电动机带动，通过齿轮齿条传动，只有三级进给速度，空行程速度太低，影响生产效率。通过改进，取消交流电动机和齿轮齿条传动机构，改成如图1所示…     

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.