人机工程学在机械维修中的应用

以机械维修过程中存在的人机工程学问题为出发点,结合维修工作的特点,对维修作业中存在的人机工程问题(操作可达性、视觉可达性和维修环境对人的影响等)进行了分析和研究.     

搞好高校后勤、维修管理工作的几点做法

1制订与执行科学、合理的管理计划要做好高校后勤、维修管理，就必须制定科学、合理的计划，使后勤、维修管理工作在计划的基础上，从整体目标出发，合理组织各个部门、各个层次的物力、财力，以便高效率、高质量的完成任务，发挥整体效能。制订计划应分清主次、轻重、缓急，应充分考虑到后勤、维修管理工作的季节性与周期性，并充分认识到工作的结合点和递进性，这样，计划就能起到指向作用、指导作用和指挥作用。计划付诸实施后，管理者对计划执行情况的监督、控制具有重要作用。监督和控制的目的，不仅在于及时发现脱离规定计划的偏差，…     

关于机械设备维修经济性的探讨

机械设备在生产过程中,不可避免地要磨耗和劣化.因此,减缓机械劣化和停机损失,保证机械正常运用,就成为生产所必须.机械的维修恰恰在这方面具有重要意义.现行的计划预修制,是以修理周期结构为支柱,按预定计划进行检修.这个制度提供了一整套管理方法,它对建立我国     

关于集材拖拉机维修经济性的探讨

为使机械设备在生产过程中,能正常运用,必须进行必要的维修。现行的预修制,是以修理周期结构为支柱,按预定计划进行检修。对建立我国机械维修体制,保证机械的正常维护,促进生产的发展,起了积极的作用。但是,随着科学技术的发展,计划预修制已经不能完全适应生产发展的需要,主要表现在过剩修理和复旧式维修两个方面,因而,它影响着维修的经济效益。本文就如何提高机械维修的经济性略述如下。     

浅谈煤矿井下机电设备维护和维修措施

对于煤矿生产作业而言,机电设备发挥了不可忽视的作用,对于企业的生产效率以及井下工人安全产生了直接影响。机电设备的正常运行离不开日常的维护与维修,也只有正确的维护与维修工作,才能够提高煤矿企业的整体质量。目前绝大部分的煤矿企业依然使用计划式维修管理方式,这种传统模式下的计划维修可能导致无效维护的出现,无法做到及时地维护,从而降低设备的使用效率,影响到企业生产效率。     

浪费时间的十种习惯

1.乱买东西。付出的不仅是金钱还有时间。2.随意许愿。明知不行却于情面许愿,浪费时间。3.解决难题。集中时间和精力去解决不能办的事情,反而误了应该办而好办的事情。4.长谈误时。5.贪看电视。6.缺乏计划。7.杂乱无章。有时找一件放得忘记地方的东西,浪费时间。8.轻视维修。有的物件需要维修而不修。9.空中等     

机械设备的维修制度及特点

机械设备的维修制度及特点（１５００４０）东北林业大学王鹤滨，李平江（１５０００１）哈尔滨工程大学徐志章机械设备的维修制度从其发展过程看，可以归纳为计划预防维修制和以可靠性为中心的维修制。本文着重阐述了这两种制度的特点，以便为林业机械设备的正确维护和修...     

浅谈森工企业机电设备状态监测

1 森工系统设备状态监测概述森工系统设备检修,几十年来一直沿袭以定期维修为主的计划检修体制,即按照规定的检修周期进行大、中、小修理.采用这种方式,可以有计划地作好设备维修的长期安排,并能与设备改造相结合,对延长设备使用寿命、保证设备正常运行曾起到了很大作用.进入80年代后,森工系统,尤其是林产工业行业,开始引进具有世界先进水平的生产设备.这些设备的特点是机电一体化,结构复杂,精度高,自动化程度高.在整个生产线上,某一细小环节发生故障,都会造成全线停机,影响生产.因此,仍然采用与设备使用累计时间有直接关系的定期检修已不能满足生产需要.为了最大限度地降低故障率,必须时刻掌握设备的运行技术状态,对关键设备、关键部位实施合理的视情维修.而开展设备状态监测是实现这一目标的重要基础.     

农机维修网点建设的现状分析及建议——以石首市为例

通过对石首市农机维修网点的调查,了解到维修网点的现状不符合《中华人民共和国农业机械维修管理规定》要求,影响农机化服务体系质量。基于存在的这类问题,提出了农机维修网点建设的布局、服务模式、创新发展等思路,给农机管理部门对如何建设发展乡村维修网点提供了调研素材和决策参考,乡村农机维修网点建设还处于初级阶段,亟待政策扶持,需要主管部门加强管理和引导。     

关于汽车维修行业危险废物处置现状的调查

指出了汽车维修行业在进行汽车维修过程中,会产生很多危险废物,通过对汽车维修行业危险废物处置现状的调查,发现了存在的问题,提出了解决问题的方法意见。     

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.