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1.
中国城市市花市树研究   总被引:1,自引:0,他引:1  
市花市树往往是一个城市的象征,反映城市市民的文化传统、审美观和价值观。调查了当前全国各省地级市及直辖市市花市树评选情况,分析了所选用市花市树的种类状况和特征及不足,发现292个城市中有167个城市评选了市树,209个城市确定了市花;所选的植物种的重复率较高,平均3个城市选用的市花或市树雷同,市花市树分布48个科,76个属,106种;市民对市花市树的认知不够,对市花市树的宣传不足,多数城市的市花市树缺少植物学名,主要以俗称为主等情况。剖析了目前这种状况的背景与原因.并为如何充分开发市花市树提出了建议。  相似文献   

2.
The reliability level of tool magazine is an important indicator to show how advanced a horizontal machining center is. To more effectively promote the reliability level of tool magazine,a new method combining importance and structure optimization is introduced. Taking tool magazine of a horizontal machinging as object, the fault tree of a tool magazine is established based on 35 failure data obtained from a horizontal machining center. Important levels of elementary events are calculated by fault tree analysis,and the order of importance is determined based on importance values. An improved design of structural reliability for elementary events with great importance is made according to failure principles and tool changing process. The feasibility of the improved design is verified by the designer of the tool magazine.  相似文献   

3.
Construction risk for water piers and foundations with double-wall steel cofferdam was analyzed by the fuzzy fault tree theory. An evaluation method of construction risk for water piers and foundations with double-wall steel cofferdam was proposed. Fuzzy fault tree of construction risk for water piers and foundations with double-wall steel cofferdam was established based on Yingwuzhou Yangtze River Bridge. 31 bottom events were considered in fuzzy fault tree model according to 2 water pier and foundation with double-wall steel cofferdam. Key process of construction risk was obtained and risk prevention measures were proposed.Results showed that fuzzy number of construction risk probability for water piers and foundations with double-wall steel cofferdam was(0.05015,0.05278,0.05542). Construction risk of 2 water pier was highest. And weld leakage, pile broken and sand boiling were the key processes with higher construction risk. There fore appropriate prevention measures would be taken to reduce the construction risk for water piers and foundations with double-wall steel cofferdam.  相似文献   

4.
This paper expounds the important meaning to guarantee and raise the reliability taking precautions against fire calamities for the system of city lifeline engineering.It quotes a large number of fire and fail cases to explain that it is a complex system engineering to evaluate the abiity of the fire systems in the city lifeline cngineering.It epresents some methods to evaluate the reliability of complex systems, these methods are being used in the different trades at the present. After comparing these evaluation methods, this paper presents the advantages and defects of analy tical method of the fail tree.It also shows clearly that this method can completely be competent at the job to analyze the reliability taking precautions against fire calamities for the city lifeline engi neering.  相似文献   

5.
This paper discusses the failure of the network, and draws a fault tree of the water distribution network. And on that basis, the fault tree is investigated through the qualitative and quantitative analysis.  相似文献   

6.
If the quantitative index of the methane explosion in coal mines before exploding can be calculated, the measure will be take to prevent the methane explosion. The methods using in the analysis of the fatalness of the methane explosion are almost qualitative analysis. In this paper the quantitative analysis of the fatalness of the methane explosion in coal mines is achieved on the basis of the research of the essence event probability with the method of fault tree analysis using the micro-computer. The practical example of the quantitative analysis of the fatalness of the methane explosion in coal mines is given.  相似文献   

7.
为使云南古茶树种质资源得到更好的保护和利用,本研究以分布在澜沧江流域部分茶区(保山市,德宏州和临沧市)的49份古茶树新梢为研究材料,利用常规方法和HPLC方法测定供试样主要生化成分含量的基础上,并通过主成分分析和聚类分析法,对供试茶样的主要生化成分含量进行生化成分多样性分析。结果表明,从变异系数(c.v.)和多样性指数(H’)可知49份古茶树新梢内含成分变异程度大且多样性丰富。聚类分析表明,供试的49份古茶树资源可聚类为A、B两大类群,两大类群的咖啡碱和酯型儿茶素(EGCG)的含量基本一致,其余生化成分含量之间均存在显著性差异(p≤0.05)。其中,采自保山市的供试样具有高氨基酸含量的特性,德宏州供试样有高咖啡碱含量的特性,大部分供试样的茶多酚含量均达到了高茶多酚含量水平,含量均>30%。本研究对构建云南古茶树资源生化成分数据库,开展茶树良种改良和品种选育具有重要意义,为古茶树的合理开发利用提供了一定的理论依据与科学基础。  相似文献   

8.
The best chance to extinguish the fire in commercial buildings is at the initial stage of a fire.For the problems during extinguishments at the initial stage of fire,a fire extinguishment system model at initial stage of fire in commercial buildings is designed.The fire data come from the fire cases in Chinese commercial buildings.The expected value and Variance of probability of basic events are calculated by using Bayesian statistical analysis method,which has overcome the difficulty from inefficient fire datum and obtaining repeated fire experience.Then the failure probability of extinguishments system at initial stage of fire is concluded from fault tree analysis and the error propagation analysis of fault tree is made.A systematic strategic decision has been made finally.  相似文献   

9.
木薯基因组SSR和EST-SSR在麻疯树和橡胶树中的通用性分析   总被引:3,自引:0,他引:3  
利用木薯的419对EST-SSR引物和182对基因组SSR引物在5个麻疯树品系和2个橡胶树品系中进行通用性分析。结果显示,木薯EST-SSR在麻疯树和橡胶树中的通用性比例分别为55.85%和38.90%,而木薯基因组SSR在麻疯树和橡胶树中的通用性比例分别为37.36%和26.37%。由此推测,EST-SSR的通用性高于基因组SSR。此外,木薯EST-SSR和基因组SSR的通用性在麻疯树中高于在橡胶树中。本研究发掘的通用性SSR引物可以用于木薯、麻疯树和橡胶树间的比较作图、基因发掘和QTL定位研究。  相似文献   

10.
为探讨绿化树种量化选择方法,观测计算郑州市常见的16 个乔木树种年生长量、固碳释氧量、固土保肥量、涵养水源量、积累营养量与净化空气功能及其价值,采用聚类与主成分分析法,对不同树种的生态服务价值进行了分析。结果表明:生态价值较高的树种为银杏(Ginkgo biloba)、悬铃木(Platanus acerifolia)、白蜡(Fraxinus chinensis)、国槐(Sophora japonica)与枇杷(Eriobotrya japonica);生态服务价值较低的树种为黄山栾(Koelreuteria bipinnata)、女贞(Ligustrum lucidum)、雪松(Cedrus deodara)、圆柏(Sabina chinensis)与侧柏(Platycladus orientalis);其他树种生态服务价值中等。建议在造林绿化中优先选择生态 服务价值较高的树种。  相似文献   

11.
Through analysis on the process of unsteady leakage of gas pipeline,the calculating model of unsteady leakage rate has been established.According to the variable characteristic of unsteady leakage ratio,based on the differential equation of on-flow diffusion,and combining the relevant original and boundary conditions,the diffusion model of unsteady leakage of gas pipeline has been established.Based on the practical application,all of the dangerous areas have been discussed and analyzed.The damaging and destroying areas have been calculated under definite conditions.This will provide safety standards and references for confirming and formulating the safety distance for the important buildings(school etc.) apart from the long high-pressure gas pipeline and main gas pipeline in city.At the same time,this will provide guarantee for reducing the dangerous degree,when accidents happened.  相似文献   

12.
为研究不同茶树品种对滇红碎茶品质的影响,以国家级茶树良种‘云抗10号’为对照,选取省级茶树新品种‘云茶红1号’、‘云茶红2号’和‘云抗12号’3个茶树新品种为试验对象,按照统一采摘标准及加工方法制成手工滇红碎茶,比较主要生化成分测定结果和感官审评结果。结果表明:3个茶树新品种茶样的内含物质丰富,生化成分比例协调;感观审评5项因子的评分结果有2个品种比对照高,得分从高到低依次为‘云抗12号’、‘云茶红2号’、‘云抗10号’、‘云茶红1号’,说明3个茶树新品种均可作为生产滇红碎茶的选用品种,尤其以‘云抗12号’、‘云茶红2号’为宜。  相似文献   

13.
野生古茶树资源主要生化成分多样性分析   总被引:1,自引:0,他引:1  
野生古茶树遗传多样性最为丰富,是最具有保护和研究价值的初级茶树种质资源。以23份野生古茶树资源为供试材料,采摘夏梢1芽2叶制备蒸青茶样,进行水浸出物、茶多酚、氨基酸总量、咖啡碱和各儿茶素组分含量等生化成分多样性分析。结果显示:水浸出物变幅为43.65%~51.19%,高水浸出物(>45.00%)资源有21份;茶多酚变幅为12.02%~38.60%,高茶多酚(>25.00%)资源有16份;氨基酸变幅为1.46%~3.41%;咖啡碱变幅为2.17%~4.91%;儿茶素总量变幅为15.52%~25.89%;非酯型儿茶素变幅为5.09%~9.84%;酯型儿茶素变幅为5.02%~16.57%,其中EGCG变幅为2.87%~10.01%,高EGCG(>8.00%)资源有4份;除茶多酚和氨基酸生化指标外,酚氨比也可以作为茶树品种适制性生化指标,初筛选出适制绿茶资源有5份,红绿茶兼制资源有11份,适制红茶资源有7份。供试23份野生古茶树资源内含物质丰富,可以作为进一步深入研究的重要资源,也为有针对性地合理开发利用和培育茶树品种提供优良资源材料。  相似文献   

14.
不同果树枝条栽培灵芝基质配方研究   总被引:2,自引:1,他引:1  
通过利用农业副产物果树枝条进行灵芝栽培基质配方优化研究,筛选出适合果树可持续发展的最佳灵芝栽培配方。本研究利用桃树、梨树和苹果树枝屑,通过不同配方优化设计进行灵芝优良菌株的栽培研究,对灵芝子实体的农艺性状进行差异分析,同时结合其氨基酸和矿质元素含量分析。结果表明:通过对灵芝子实体农艺性状差异分析,苹果-2配方表现最好;通过对氨基酸含量分析,配方组氨基酸含量顺序为桃树组配方>梨树组配方>苹果树组配方;综合9个配方中灵芝子实体内矿质元素含量分析,梨树-1配方表现最佳。以上不同的配方栽培出的灵芝其产量、氨基酸和矿质元素含量各不相同,芝农可根据不同的需要而选择合适的灵芝栽培基质配方。  相似文献   

15.
介绍了星座图聚类分析应用于茶树品种区域试验定量化评价的方法,并对1997—2002年全国茶树品种区域试验河南点试验数据进行了星座图聚类分析,结果表明:其分析结果与常规分析方法基本一致,说明星座图聚类分析法应用于茶树品种区域试验中对试验结果作综合判定是可行的,而且可对茶树综合性状作出定量的评价分析,弥补了常规分析方法的单纯性。  相似文献   

16.
玉溪城市绿地园林树木多样性调查研究   总被引:1,自引:0,他引:1  
按绿地类型和干扰类型,分别调查了玉溪城市园林植物群落,对比分析了各类型绿地植物群落树木的优势度指数、Simpson指数、Shannon指数等指标。结果表明:(1)自然森林乔木层的优势度较大,乔木层优势种的集中程度高。(2)自然型绿地群落乔木种类的多样性低于人工型绿地植物群落。(3)城市中不同类型绿地植物群落总体的物种多样性依次为公园绿地>校园绿地>广场绿地。  相似文献   

17.
不同花型牡丹品种亲缘关系的SRAP分析   总被引:2,自引:1,他引:1  
为了从分子水平上揭示牡丹品种间的遗传差异,本研究用SRAP-PCR技术对20个牡丹品种进行基因组DNA多态性分析,并用UPGMA法构建系统发育树,结果表明,20对引物扩增出131条清晰、稳定的DNA条带,其中90条谱带表现多态性,多态性检测率为68.7%,表明受试牡丹品种之间含较丰富的遗传多态性。UPGMA聚类结果表明,部分花型相同的品种相聚,但部分花型不同的品种亦相聚。说明聚类结果与牡丹品种的花型间可能有一定的相关性,但并未有完全一致的关系。  相似文献   

18.
为了探究半干旱地区苹果树的需水规律,以封闭果树根域土壤为试材,防止地面蒸发,采用定期连续测定土壤含水量的方法来测算果树的蒸腾量。结果表明:9年生矮化中间砧果树吸收土壤水分的主要垂直空间在0~60 cm土层,60 cm以下土层含水量变化不明显。果树秋季蒸腾耗水量为134 kg/棵,春季萌芽到花期,蒸腾耗水量为104 kg/棵。因此,在进行田间管理时,以0~60 cm湿润层确定节水灌溉较为科学。  相似文献   

19.
环境因子对茶树产生化感物质的影响   总被引:2,自引:0,他引:2  
采用定点定位方法 ,对影响茶树产生化感物质的环境因子即种植密度、机械损伤、不同茶叶品种、不同生长阶段、茶叶不同叶位生化特征、温度、光照等的调查研究 ,可以了解环境因子对茶树产生化感物质的影响。为茶叶高产、稳产以及茶叶生产的可持续发展提供理论和实践指导。  相似文献   

20.
应用基于决策树的数据挖掘算法对农产品电子商务B2B系统中的历史竞标样本进行了分类,通过给出一个结合实例的算法实现过程,说明了供应商在竞标过程中产品报价等部分影响因素间的一些潜在性规则,从而得出不同特征的农产品供应商在虚拟市场中的竞标能力高低差异依次由产品报价、配送及时率、市场需求水平等因素决定。  相似文献   

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