林区电力系统继电保护装置的应用

随着林产工业及木材综合开发利用的发展林区电力系统也随之飞速的建成和发展,电力系统的形成完全取代了过去各个林场单独由柴油机发电机组发电供电的落后状态,由于电力系统的形成,电力系统在运行中经常出现各种故障和不正常的运行方式,为了     

浅议森工林区农（电）网的改造

为了降低农村电价，减轻农民负担，提高农民生活水平，开拓农村市场，繁荣农村经济，国务院于１９９８年提出了在全国范围内对农村电网进行建设与改造。黑龙江省森工林区基本上是由农网供电的，并且符合农网的条件，所以黑龙江省将森工林区电网改造列入农村电网改造的增补方案，并获得国家计委的批准，该工程预计在 ２００１年开始动工。１黑龙江省森工电力系统存在的问题 我省森工林区经营面积大，地处偏远，电力设施都是由森工系统多方筹集资金自行建设的，经过几十年的努力，森工自备电力系统已具备一定的规模，形成了较为完整的发供电管…     

贮木加工厂电网的技术改造

牡丹江林区十个林业局的贮木加工厂是各局用电设备最多、用电量最大的单位。随着木材生产形势的不断发展,用电设备也逐年增加。多数贮木加工厂的供电点多达5～10处,配电变压器多达7～11台,总装机容量超过2000kVA 以上,造成电费多,电量损失大的不合理局面。不但增加了事故点及维护工作量,而且在很大程度上影响企业用电经济     

浅谈迎春林区电业局电网发展的改造工程

保障性安居工程是国家对林区发展实施的一项重大工程,其中包括对林区电力系统的升级改造工程项目。本文以黑龙江省迎春林业局的供电现状为例进行论述,并根据实地电力设施情况和未来需求预测提出相应的供电工程改造方案。     

森林灾害动态监测防治与预测模型研究

以３Ｓ技术为核心，以松材线虫和为害杨树的杨尺蠖、杨舟蛾及大兴安岭林火为背景，根据各类森林虫源和林火的生物特性及影响的波谱特性，研究森林灾害的空间展布规律，建立动态监测模型，提出了林区业务化的灾害动态监测，治理方案优化一体化的系统构建，为林区生态变化预测、动态管理及可持续发展决策提供科学依据和保障     

林区生态环境监测的无线传感器网络数据融合技术研究

针对林区生态环境监测系统中的数据高冗余度,提出一种基于LEACH路由协议的无线传感器网络(WSN)数据融合算法。通过林区高密度的反馈数据,验证该算法提高了数据融合的高效性,该算法针对周期性的信息反馈的无线传感器网络特别适用。因为林区的一些生态数据的监测只是周期性的去采集处理,所以该算法适用于林区的高数据周期性的数据采集、融合和处理。     

大兴安岭林区电网长远规划探讨

大兴安岭林区电网地处我国东北部边缘,距国家电网较远。多年来为林区的开发建设,提供了可靠的电力资源。目前大兴安岭林区由于行政区划及管理体制原因存在着两个林业电力系统:大兴安岭林管局电业局供电的加格达奇～塔河电网和牙克石林管局根河电业局供电的根河电网。这两个电网从1969年起曾一度联网,后于1973年在阿里河变     

一种10 kV线路跌落开关监测保护装置的开发与利用

配网系统是整个电力系统中终端的重要组成部分，是直接面向客户供应和分配电能的重要环节。配电线路设备数量多、分布广泛，一旦发生故障，停电损失和影响不容忽视，对用户供电可靠性的影响很大。研究开发一种10 kV线路跌落开关监测保护装置，可有效缩短线路抢修时长，提高供电可靠性及可转供率，缩小停电范围、降低停电影响，具有巨大的社会效益和经济效益。     

关于林业系统电价与电费管理改革的思考

随着改革开放的进一步深入，我国由社会主义计划经济管理模式，向社会主义市场经济管理模式转变。在这种情况下，林业系统电力行业的管理人员对电价与电费管理怎样增收挖潜．是值得研究的问题。根据十多年来从事用电管理工作的经验，对林业系统电价与电费管理中的有关问题进行探讨。1林业系统电价执行现状1．l基本电价。在计算基本电费时，是以用户用电设备容量（千伏安）或最大容量（千瓦）为单位计算，与用户应用实际用电量无关。1．2电度电价。计算电度电费时，则以用户的实际用电量为单位计算，而与用户的装接设备容量或最大需电量无关…     

基于模糊控制的林区电力系统集控站驾驶舱响应模式研究

本文的研究目的在于满足林区电力系统的多样化运行要求,并提升对其运行控制的操控能力,与此同时解决光伏和风力发电带来的供电不确定问题。基于电网所应用的一体化智能电网运行系统(OS2),提出基于模糊控制的集控站驾驶舱动态响应模式。文中所给出的模糊判读系统根据关键性能指标(KPI)的给定信息作为参考输入,根据模糊逻辑推论得到在所给出的性能评估指标下所需要采取的电网运行决策指令。所设计的模糊逻辑系统在满足上述要求的同时,采用反馈机制,对所给出的决策进行实时检验,以确定其作用效果,满足高性能运行控制的要求。仿真结果对所提出的基于模糊逻辑的响应决策系统进行了有效验证。所得到的理论分析及仿真验证结果可以有效的表明基于模糊控制的林区电力系统集控站驾驶舱具有良好的响应效果。     

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.