共查询到20条相似文献,搜索用时 93 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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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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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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由于全球气候变化而导致的气候干旱正严重影响着我国的西部地区,黑河流域上游过度的农业开发和城市用水的快速增加,导致下游的额济纳绿洲干旱缺水严重,为了解决这个问题,修建了狼心山水利枢纽工程。此工程虽然部分的解决了干旱缺水的问题、但也存在着弊端。如何解决这一工程缺陷,是今后研究的问题,文章提出了解决的方法供参考。 相似文献
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福建长汀河田水土流失地区的迳流试验及类芦的绿化效果分析 总被引:7,自引:0,他引:7
在福建长汀河田水土流失地区建立迳流小区,进行迳流试验研究,并以优良乡土草种——类芦为主栽草种进行快速绿化,以迳流试验分析其水土流失治理效果。经过两年的试验,获得了可靠的数据,收到了明显效果,类芦生长旺盛,植被覆盖率达90%以上,使治理区地表年迳流量减少31.2%,土壤年侵蚀量减少52%,严重的水土流失现象基本得到控制,生物多样性明显增加,绿化效果显著。类芦在水土流失地区的推广应用前景广阔。 相似文献
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当静压线的高度以一般建筑内低压铸铁散热器的承压能力来确定时,高层建筑空调水系统或高区采暖系统能否与外网采取直接连接方式,且不使用阀前压力调解器与外网进行静压隔绝,而一般建筑内低压铸铁散热器还不超压,以达到节约初投资和方便运行管理的目的。 相似文献
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本文叙述了进行“一户一表”改造的必要性和常用方案,对实施过程中出现的问题进行了分析 并提出解决方案。 相似文献
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叶芽组培西洋杜鹃最佳生根途径试验研究初报 总被引:2,自引:0,他引:2
为了克服西洋杜鹃(Eurhododendron)组培快繁移栽成活率低的问题,对其进行了组培最佳生根方式试验,结果表明,叶芽(茎尖)组织培养的新株,用生根粉处理进行扦插水培,其生根率达90%以上,较试管培养高16%,较基质扦插高50%;育苗周期较试管培养和基质扦插缩短约20 d;移栽成活率较试管培养和基质扦插分别高35%和84%。因此,用生根粉处理后进行扦插水培是西洋鹃最佳生根方式。 相似文献
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钢筋混凝土结构加固是近年来建筑界讨论比较多的问题,随着建筑材料的发展,各种新型材料源源不断的被研发出来并被采用,问题的研究也再不断深入,建筑物改造与危害处理也越来越受到重视,并且被广泛关注起来。其中房屋的加固抗震尤为重要,本文主要谈及钢筋混凝土房屋结构的抗震加固问题。 相似文献
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云南1998年后定植的橡胶树多数在橡胶树三等宜林地,或其边缘地区,非生产期延长,甚至10年、10年以上都不能达到投产标准,是云南天然橡胶种植业存在的一个大问题,需要尽快组织力量调查和专门研究对当前种植多年尚未投产的橡胶林的整顿、调整、巩固的重要技术和经营措施。 相似文献