共查询到20条相似文献,搜索用时 109 毫秒
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木棉(Gossampinus malabarica)又名攀枝花、红棉、英雄树、烽火树,属木棉科木棉属落叶高大乔木.木棉广泛分布在我国四川、云南、贵州、广西、广东,生长在江河沿岸、山地阳坡及村边道路旁,喜光、耐高温,对土壤要求不苛刻.在四川攀枝花地区木棉树于1月-2月份开花,先花后叶,花色艳丽,有红色、金黄、淡黄色等颜色,树形高大伟岸,是优良的园林绿化树种.木棉树现是攀枝花市市花和广州市市树,在园林绿化中常作行道树、庭荫树、景园树、盆景树等.木棉经嫁接后2 a-3 a开花,嫁接苗可作盆景矮化栽培,观赏价值高.本文介绍了木棉的嫁接育苗技术. 相似文献
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One compound approach combining factor-analytic model with AMMI and GGE biplot to improve multi-environment trials analysis 总被引:1,自引:0,他引:1
To improve multi-environmental trial(MET)analysis,a compound method—which combines factor analytic(FA)model with additive main effect and multiplicative interaction(AMMI)and genotype main effect plus genotype-by-environment interaction(GGE)biplot—was conducted in this study.The diameter at breast height of 36 open-pollinated(OP)families of Pinus taeda at six sites in South China was used as a raw dataset.The best linear unbiased prediction(BLUP)data of all individual trees in each site was obtained by fitting the spatial effects with the FA method from raw data.The raw data and BLUP data were analyzed and compared by using the AMMI and GGE biplot.BLUP results showed that the six sites were heterogeneous and spatial variation could be effectively fitted by spatial analysis with the FA method.AMMI analysis identified that two datasets had highly significant effects on the site,family,and their interactions,while BLUP data had a smaller residual error,but higher variation explaining ability and more credible stability than raw data.GGE biplot results revealed that raw data and BLUP data had different results in mega-environment delineation,test-environment evaluation,and genotype evaluation.In addition,BLUP data results were more reasonable due to the stronger analytical ability of the first two principal components.Our study suggests that the compound method combing the FA method with the AMMI and GGE biplot could improve the analysis result of MET data in Pinus teada as it was more reliable than direct AMMI and GGE biplot analysis on raw data. 相似文献
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Natural spruce-fir mixed stand is one of the main forest types in the world,and also has huge ecological,economic and social benefits.According to the structural characteristics and succession laws of natural spruce-fir forest,it is urgent and significant to develop scientific management measures for natural spruce-fir mixed stand in line with local conditions.The article outlined the characteristics of the distribution and structure, regeneration and succession laws of natural spruce-fir forest,and analyzed the current situation and existing problems of natural spruce-fir forest management.The following recommendations were eventually made:1) In no cutting area,all logging activities should be banned.In a restricted cutting area,the cutting intensity should be generally controlled within 15%of the stock volume before cutting.On the commodity forest management area, the appropriate cutting intensity should be determined according to the volume per hectare,determine and classification management should be implemented in accordance with the characteristics of forest,to ensure the scientific selective cutting.2) Closure for afforestation,planting and repair planting should be adopted on vegetation-intensive land,sparse shrubs covered land and harvesting slash,in order to accelerate natural regeneration.3) The in situ conservation should be conducted in nature reserves and scientific experiment stations of rare and endangered species,such as Abies chensiensis,Picea neoveitchii,Abies vuanbaoshanensis,to reduce human destruction.4) It is supposed to collect seeds in time,establish nursery,actively establish forest, expand artificial population and promote natural regeneration. 相似文献
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《技术与市场》2007,(1):23
当前现代化的航天、航空、汽车、机械、电子、民用建筑、化工等行业迫切要求具备很高的力学性能及耐热、耐磨、耐化学性能的材料.因此高分子材料发展的一个重要方向就是通过对现有聚合物进行物理和化学改性,使其进一步高性能化、结构化、工程化.北京化工大学研制的聚氯乙烯合金是通过挤出机的力学、化学作用及接枝、复合技术使聚氯乙烯塑料工程化,成为物理性能可与ABS相比拟的新材料.聚氯乙烯合金具有高流动性、高韧性,完全可以代替ABS注塑计算机、电视机、冰箱、照相机、仪表等外壳.聚氯乙烯合金还具有良好的耐寒性,可制作各种规格的异型材,包括门窗、上水管道等.产品市场前景好,具有很强的竞争力,有很好的经济效益和社会效益. 相似文献
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According to the unification principle of system structure and system function of the Water Resource Conservation Forests,seven factors were selected from stand spatial structure,trees structure and healthy of woods,the multifunction management optimization model target was confirmed by using nonlinearity multi-objective programming approach, and the target function-stand spatial structure homogeneity index was defined to establish spatial optimization models with restraining conditions set up in diversity of stand structure and spatial structure.The spatial structure of available typical stand in the wet land area in southern Donting Lake was optimized by means of selective cutting and reinforcement planting.The results showed that the spatial structure was improved obviously and trees diversity and stand health were not weakened.It’s suggested that the established optimization model can effectively guide multifunction management,stand structure optimization and the steadiness of ecological ecosystem and it is convenient and operable in practice,and it’s very important to protect and recover ecosystem of Water Resource Conservation Forests. 相似文献
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This paper proposes an automatic method of pore combination recognition,which is an important feature to hardwood recognition.After extracting edge from wood microscopic cross-section, based on area histogram of the similar circle regions,the method classifies all regions into two classes with maximum between-class variance,so as to distinguish the pore from other textures,which are similar in shapes but different in sizes.Meanwhile, second objective function about average area of closed regions is used to improve the pore segmentation performance.At last,the method uses adjacency degree of pore set to judge pore combination.The experiments demonstrate that the task of pore segmentation can be completed successfully for all kinds of pore distribution and combination,and also the correct combinations of pores are given. 相似文献
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汽轮机降低真空运行,提高循环水温做为冬季供暖是一项社会效益和经济效益都十分显著的节能技术,下面把利用汽轮机低真空运行循环冷却水采暖技术及其显著的经济效益简述如下。 相似文献
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分析低碳园林的实现途径,旨在更好地推广低碳理念,同时为低碳园林建设提供理论依据,也为今后低碳理念在园林景观设计中的进一步应用提供参考资料。
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指出了低碳交通运输是实现节能减排,发展低碳经济的重要组成部分。分析了低碳交通运输的内涵,探讨了通过发展低碳交通运输,以促进经济的可持续发展,并提出了相应对策与建议。 相似文献
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主要探讨低噪音沥青混合料的研究和应用工作。首先,分析低噪音沥青路面的特点,研究交通噪音分类及其产生机理,提出解决噪音的主要措施;其次,对比分析国内外传统的低噪音沥青混合料矿料的级配范围,提出改进的矿料级配范围,并进行相应的低噪音沥青混合料设计。在某公路上铺筑了试验段,探讨低噪音沥青混合料的施工方法,试验段与普通路段的对比检测结果显示本研究的设计具有良好的效果。 相似文献
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基于小批量生产的统计过程质量控制的研究 总被引:4,自引:0,他引:4
用概率积分变换理论,给出了控制过程均值、过程方差的标准化控制图,适用于小批量生产环境下对过程均值、过程方差的有效控制。 相似文献
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对从化流溪河林场和连平九连山林场的毛竹低产林进行改造试验,结果表明:毛竹低产林进行带状垦复,并合理施肥等改造措施,林分各项生长指标均得到提高,以九连山林场改造效果较为理想。与对照比,从化试验地的毛竹改造林分高、竹产量达0.10水平显著差异,但胸径差异不显著,树高、胸径和竹产量增益分别为5.1%,1.2%,21.2%;连平试验地的改造林分高、胸径和竹产量三项指标均达0.0l水平显著差异,其增益分别为49.5%,55.0%,192.7%。通过改造,能够改善毛竹的生长环境,提高发笋率,促进竹笋萌发成长为新竹,同时可以提高毛竹质量和产量。 相似文献
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云南省低产林改造面临的问题及对策措施 总被引:1,自引:0,他引:1
云南省森林面积大,质量不高,立地条件较好的林地多已绿化成林而限制了林业的进一步发展,因此,实施低产林改造,最大限度地发挥林地生产力已成为云南省林业发展中重要而紧迫的任务。文章阐述了低产林的概念及标准,深入分析了云南省低产林改造工作中面临的问题,并针对不同的问题提出了相应的对策措施。 相似文献