SF-23/17.2-YQ锅炉热力除氧现场应用分析

对影响除氧器的除氧效果因素进行分析,并提出提高除氧器除氧效果的对策。     

cy5型油锯

孟窿黯欢黯篙瓢头装有滚针轴承,其它膊动部位也都采用滚动轴承。渭滑方式除离合器和起动器两处孩卦轴气汽油机,其拮构特点,采用单向伐曲轴箱配气。扒上装有起动器、起动油尸,限位按纽丫停火开关和消滑姗雄的机油泵,操作方便。全机除汽缸和运动件外,大部份为镌合金撼件,以减i理机体重量。汽缸采用铅合金压霎幕,内表面电镀硬铬,光滑耐磨。活塞采用共晶体硅绍合金稳成,曲轴为祖合式,用整体式速杆,大小承用消滑脂外,其余全由混合油雾俏滑。点火系杭为飞李俞磁一电机式,其膊子与飞输凤扇压磷成一体,使桔构筒化。供抽某就采用Qn台型泵膜式汽化器,…     

压风机冷却降温及余热利用技术探讨

分析了潘西井及其压风机使用情况,探讨了压风机冷却降温及余热系统的原理和构成,对其运行效果进行了研究,以保证压风机的安全运行,实现环保节能的目的。     

伞滑刃线虫交合刺形态图像的规范化和定位算法

应用数字图像处理与分析技术中的最小外接矩形算法和镜像变换算法,用Visual c 作为开发工具,通过编程实现计算机对伞滑刃属线虫交合刺形态图像鉴定规范化和定位的智能化。输入伞滑刃属66个有效种的交合刺形态图像运行程序,均获得正确的定位结果。     

蜗壳保温保压混凝土施工技术——以锦屏二级水电站地下厂房施工为例

锦屏二级水电站厂区枢纽工程地下厂房蜗壳保温保压混凝土采用布料机浇筑,混凝土泵机浇筑配合的施工方法,能够较好地解决混凝土入仓难,座环底部混凝土灌不满的问题。在蜗壳内充水保温保压浇筑二期混凝土,模拟蜗壳在运行状态下浇筑,为蜗壳的安全、永久运行提供有力的技术保障。     

丹滑8号生物学特性及高产栽培技术要点

本文通过对丹滑8号生物学特性、高产栽培技术要点描述，完善了丹滑8号托盘木屑半熟料开放式栽培技术，为丹滑8号成为北方滑菇主栽品种起到推动作用。     

Δ一条适合多种工艺的短周期压贴线建成投产

从联邦德国BUKLE公司引进的年加工能力为65万平方米适合多种工艺的低压短周期压贴生产线最近在吉林省三岔子林业局建成,并通过性能考核,全线投入生产运行。这条压贴线具有工艺灵活、适应性强、效率高、技术先进、操作简便等特点。贴面     

带锯齿自动压料机

我国制材工业中,仍普遍采用手工压料机。近年来由于大径级进口原木日益增多,制材质量要求不断提高,采用厚锯条(19~#18~#)也普遍回升。而手工压料用力不匀,很难达到锯料的一致性,修锯工普遍反映劳动强度高,既费工又费时,因此希望压料自动化。理论依据和技术条件1.压料机必须适应齿距变更的灵活性.齿距与锯机型号、锯厚、材种有关,一般齿距在32～38毫米之间。因此在设计上应具有灵活调节的机构。2.机床运行的稳定性.要求机床运行时的重心平衡、动作协调,而电机与减速箱的联接方式、指令性中心机构等,是保证稳定性的关键。3.锯厚的适应性.能适应20~#、19~#、18~#三种厚度的带锯压料。     

高等级公路沥青路面抗滑性能研究

在分析高等级公路沥青路面抗滑机理的基础上，通过研究影响抗滑性能的主要因素，结合国内外研究成果和工程经验，提出了高等级公路沥青路面提高抗滑性能的技术要点。     

单片机在交流电机变频调速系统中的应用

本文介绍了用8031单片机，与脉冲宽度调制专用集成电路设计而成的功率晶体管逆变器的控制器．采用本控制器对交流电机进行变频调速，可使电机实现平滑加速、平滑减速并进行过载保护、过压保护和欠压保护．对实现电机的节能运行有重要的意义．     

Canopy management possibilities for arboreal Leucaena in mixed sorghum and livestock small farm production systems in semi-arid India

A major problem for small farmers in the semi-arid tropics is the chronic shortage of fodder for draft animals. Leucaena leucocephala has improved productivity in many places in India and in various cropping systems, usually as either a pure crop or in a hedgerow alley-cropping configuration. Mixed cropping with arboreal forms is seldom seen. For off-season fodder production, hedgerows have the disadvantage of being open to unmanaged browsing when unfenced (as is usual). Arboreal forms are generally far less vulnerable. In this paper, the components of production of sorghum and arboreal Leucaena are measured under different intensities of canopy lopping. The most productive management system of those examined was pollarding of the Leucaena at the time of under-sowing with sorghum. In a year with less than 50% of average seasonal rainfall, this system gave a yield of 4.6 tonnes/ha/yr fresh wt fodder and 3.8 tonnes/ha/yr dry wt. of fuel harvests, while increasing the standing crop of wood by 1.8 t/ha/yr and retaining a yield of sorghum grain equivalent to 46% of pure sorghum cropping; the LER of this system was 1.35. Cash values of the alternative management systems were estimated, including the discounted Net Present Value of the standing crop of timber. Maximum value was attained with unlopped pure crop Leucaena followed by pollarded Leucaena with sorghum; pure crop sorghum achieved a lower value. These results demonstrate both the high productivity of Leucaena/sorghum based systems, and the stability of production even in poor rainfall conditions. Pollarding transferred the high future value of Leucaena timber to the present value of sorghum grain and fuelwood.     

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.     

天牛体内纤维素酶研究进展

文章综述近年来国内外有关天牛体内纤维素酶的研究进展,主要包括:天牛体内纤维素酶的来源、不同天牛种类纤维素酶的性质、纤维素酶抑制剂、纤维素酶同工酶、纤维素酶基因以及天牛体内纤维素酶活性变化与寄主的关系,并展望了未来的研究方向。     

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.     

Modeling spatial variability and pattern of rust and brown eye spot in coffee agroecosystem

The advent of Precision Agriculture has made possible the analysis of complex spatial patterns of plant disease epidemiology considering statements of integrated disease management. The objective of this work was to use geostatistics, statistics and geographical information systems to characterize the structure and magnitude of spatial dependency of rust (Hemileia vastatrix) and brown eye spot (Cercospora coffeicola) incidence and severity in coffee agroecosystem cultivated with Catuai Vermelho IAC-99 (Coffea arabica L.). Evaluations of incidence and severity of rust and brown eye spot were accomplished at 67 georeferenced points arranged in 6.6202 ha of coffee crop, in the years of 2005, 2006 and 2007. Exponential models of covariance enabled the characterization of the magnitude and structure of rust and brown eye spot spatial variability in the evaluated dates. Ordinary block kriging presented satisfactory performance to map rust and brown eye spot outbreaks based on kriging error coefficients. Kriged maps enabled the visualization of intensity of rust and brown eye spot in each evaluation date. Assessments of incidence and severity presented highly statistical correlation based on linear regression models, also confirmed by the spatial variability of kriging maps. Kriging maps of rust and brown eye spot enabled to observe that intensity of disease was dispersed in foci patterns along the coffee plantation, indicating that the current strategy of disease control based in total area may be replaced by site specific disease management, with less environmental impact and sustainability of coffee crop, according to statements of integrated disease management and precision agriculture.     

Nutrient cycling and growth in forest ecosystems of south western Australia: Relevance to agricultural landscapes

Nutrient and hydrologic cycles in harvested native forests in southern Australia are largely balanced. For example, we have little or no evidence of any decline in nutrient capital or availability in harvested forests. Short-term and small-scale reductions in evapotranspiration due to loss of leaf area after harvesting are adequately balanced at the landscape scale by large areas of regenerating or older-age forest. In contrast, agricultural systems on similar soils are a) dependent on large inputs of fertilisers to maintain growth and b) frequently subject to increasing salinity and waterlogging or other forms of degradation. The large-scale replacement of long-lived communities of perennial and often deep- rooting native species with annual crops or other communities of shallow-rooting species might be better managed within the framework of knowledge developed from studies of native plant communities. However, application of such a mimic concept to systems of low natural productivity is limited when agricultural systems require continued high productivity. Nonetheless, the mimic concept may help in developing sustainable management of agriculture on marginal lands, and contribute to the nutritional resilience of agroecosystems. Relevant characteristics for mimic agroecosystems in south western Australia include: high species diversity, diversity of rooting attributes, utilisation of different forms of nutrients (especially of N and P) in space and time, and the promotion of practices which increase soil organic matter content. This revised version was published online in June 2006 with corrections to the Cover Date.     

Native woody species regeneration in exotic tree plantations at Munessa-Shashemene Forest,southern Ethiopia

Regeneration of native woody species was studied in the plantations and the adjacent natural forest at Munessa-Shashemene Forest Project Area, Ethiopia. The aim of the study was to test the hypothesis that tree plantations foster regeneration of native woody species. A total of 60 plots, having 10 × 10 m area each, were studied in monoculture plantations of 4 exotic species (Cupressus lusitanica, Eucalyptus globulus, E. saligna, Pinus patula) and an adjacent natural forest. Ages of the plantations ranged between 9 and 28 years. Soil seed bank analysis was also undertaken from soil samples collected in each of the 60 plots to examine the similarity between the soil seed flora and aboveground vegetation. A total of 56 naturally regenerated woody species were recorded beneath all plantation stands with densities ranging between 2300 and 18650 individuals / ha in different stands. There was a significant difference among plantation stands with regard to understorey density (standard deviation: 4836 ± 1341). Vegetation diversity was assessed through analyses of floristic composition, species richness and abundance. Generally, seedling populations were the most abundant components of the regeneration in most of the plantation stands, forming 68 % of the total regeneration count in all stands. A total of 77 plant species represented by 44 herbs, 13 woody species, 8 grasses and 12 unidentified species were recorded in the soil seed bank from all stands. Similarity between the soil seed bank and aboveground flora was very low implying that the role of soil seed banks is negligible rather dispersal plays an important role in the process of regeneration. These results support the concept that forest plantations can foster the regeneration of native woody species, thereby increasing biological diversity, provided that there are seed sources in the vicinity of the plantations.     

Trees and shrubs as sources of fodder in Australia

Experience with browse plants in Australia is briefly reviewed in terms of their forage value to animals, their economic value to the landholder and their ecological contribution to landscape stability. Of the cultivated species only two have achieved any degree of commercial acceptance (Leucaena leucocephala and Chamaecytisus palmensis). Both of these are of sufficiently high forage value to be used as the sole source of feed during seasonal periods of nutritional shortage. Both are also leguminous shrubs that establish readily from seed. It is suggested that a limitation in their present use is the reliance on stands of single species which leaves these grazing systems vulnerable to disease and insects. Grazing systems so far developed for high production and persistence of cultivated species involve short periods of intense grazing followed by long periods of recovery. Similar management may be necessary in the arid and semi-arid rangelands where palatable browse species are in decline.     

Measurement of Green Plank Shape for Prediction and Elimination of Compression Wood

The objective of this study was to predict the amount and the distribution of compression wood (CW) within a Norway spruce [ Picea abies (L.) Karst.] plank based on green plank curvature. The findings indicated a possibility of predicting the longitudinal distribution of CW from the green plank curvature. Areas free from CW showed a typical concave shape in relation to the centre of the log, while CW was present when a convex shape was shown. The larger the magnitude of convex curvature, the higher the concentrations of CW that could be found, and a larger fraction of dried planks was rejected due to excessive warp. This study also determined what information can be used to eliminate areas of high concentrations of CW by cutting and how cutting affects the grading results with respect to warp. Over 50% of the plank length showing a high concentration of CW (>30% of the cross-cut volume) was successfully cut off. Cutting strategies based on predicted CW concentrations resulted in a 10-40% increase in accepted plank length.     

闽南山地木荷林套种南方红豆杉的试验

为了解南方红豆杉在闽南山地生长所需的环境条件,开展了木荷林下套种南方红豆杉的试验研究,结果表明,在较高郁闭度的木荷林中套种南方红豆杉,随木荷林郁闭度的增大,南方红豆杉的树高、地径和生物量降低,叶绿素含量减少,养分含量下降。郁闭度为0.5的木荷林套种南方红豆杉,其生产力最高,叶绿素含量和养分含量均最大。