无性繁殖常用的方式

无性繁殖常用的方式有三种,扦插、压条和嫁接。本文论述了这三种无性繁殖的具体作法。     

Short-term Model of the Production of Construction Aggregates in Taiwan Based on Artificial Neural Networks

BACKGROUND: Taiwan's geography and limited stock of sandstone have caused sandstone resources to gradually decline to the point of exhaustion after long-term excavation. Moreover, the Taiwanese government has continuously increased the amount of land area near rivers that cannot be excavated to facilitate riverbed remediation and promote conservation of water resources. Accordingly, predicting and managing the annual production of construction aggregates in future construction projects, and dealing appropriately with some thorny problems, for instance, demand that excess supply, excessive excavation, unregulated excavation, and the consequent environmental damage, will significantly affect the efficient use of natural resources in a manner that accords with the national policy of Sustainable Development (SD). METHODS:. This study establishes an empirical model for forecasting the annual production of future construction aggregates using Artificial Neural Networks (ANN), based on 15 relevant socio-economic indicators, such as indicator of annual consumption of cement. A sensitivity analysis is then performed on these indicators. RESULTS AND DISCUSSION: This work applies ANN to estimate the annual production of construction aggregates; the estimates, the verification of the model and the sensitivity analysis are all acceptable. Furthermore, sensitivity analysis results indicate that the annual consumption of cement is the indicator that most strongly influences the production of construction aggregates, as well as whether construction waste can be recycled and steel structures can be used in buildings, helping to reduce the future production of construction aggregates in Taiwan. CONCLUSIONS: The elaborate prediction methodology presented in this study avoids some of the weaknesses or limitations of conventional linear statistics, linear programming or system dynamics. Additionally, the results not only provide a short-term prediction of the production of construction aggregates in Taiwan, but also provide a viable and flexible means of verifying quality certification of the production data of construction aggregates in the future by incorporating those relevant socio-economic indicators. RECOMMENDATIONS AND OUTLOOK: The continuity and quality of the database of relevant indicators used in this study should be closely scrutinized in order to ensure the SD means of exploiting resources.     

菊花组培快繁技术研究

以菊花嫩茎段为材料,进行无菌系建立、芽分化、生根等试验,探讨菊花组培快繁技术.结果表明:(1)以MS BA2.0 mg.L-1 NAA0.1 mg.L-1(单位下同)为培养基,分别置于普通培养室(不开灯,200~500 lux)与人工气候箱中培养,在前者条件下基本上不诱导芽的形成,25天后有部分黄白色愈伤组织形成;而在人工气候箱中培养则产生丛生芽,每茎段在30 d后可形成8~10个丛生芽.(2)分别以①MS BA1.0 NAA0.1,②MS BA2.0 NAA0.1,③MS BA3.0 NAA0.1为增殖培养基,培养25 d后芽增殖3.65~5.90倍.(3)在a.1/2MS NAA0.2;b.1/2MS IAA0.2;c.1/2MS IBA0.2共三个培养基中进行生根培养,生根率均达100%,但前两个培养基中长出的根系细长、数量少,而后一个培养基则根系粗短、数量多.     

麻疯树愈伤组织的诱导及快速繁殖

以麻疯树(Jatropha curcas)的种子、叶柄、叶片为实验材料进行愈伤组织的诱导及快速繁殖的实验．用不同浓度的BA和IBA对其不同外植体进行试验，发现用MS培养基加0．5mg／LBA和1mg／L IBA对叶片的效果最佳．在相同BA浓度处理条件下，减小IBA浓度会对下胚轴愈伤组织的出芽产生明显的效果．叶柄要求的浓度更低，0．1mg／L BA和0．1mg／L IBA为最佳．不定芽在无激素的MS培养基中进行生根培养，通过几天的练苗过程，就能转到土壤中生长．图1表2参13     

中国公众环境意识提高的若干建议

中国公众的环境意识“知”强“行”弱,总体水平较低,主要与几十年来的体制、经济水平和文化素质有关。应增强环境宣传力度和深度,在学校中普设环境教育课,提高公众的环境法律意识和环境道德意识,宣传绿色文化,从而提高公众的环境意识。     

滇池流域冲沟和强侵蚀区水土和氮磷流失综合控制技术研究

介绍了滇池流域冲沟和强侵蚀区水土和氮磷流失控制研究的内容、方法及取得的效果等.     

基于Ⅰ-Ⅱ复合型裂纹破坏模式的条带矿柱破坏宽度研究

采用条带法进行地下开采时,条带矿柱的裂纹扩展导致了矿柱的最终破坏,且裂纹多表现为Ⅰ型裂纹与Ⅱ型裂纹复合扩展破坏特征。根据采场矿柱受力条件,确定条带矿柱受两侧采场空区影响时矿柱内Ⅰ-П复合型裂纹尖端的Westergaard应力函数,采用HoekBrown强度准则计算采场作业面围岩破坏区的边界条件,建立了矿柱破坏宽度计算模型。以上横山页岩矿床为研究对象,采用物理相似模拟试验,模拟条带法回采某盘区3个试验区段,利用DIP法分析受地应力及回采扰动作用下矿柱的裂纹发育特征,验证模型的有效性。结果表明,条带及其条带矿柱均为15 m等设计参数条件下,计算模型矿柱破坏宽度理论值分别为17.66 m、15.56 m和10.28 m,试验模拟结果分别为完全大于15 m、约为15 m和10.5~11.0 m,试验结果与依据模型计算的理论值相近。     

基于PCA-BP神经网络的多股铜导线 熔痕定量金相识别方法研究

为实现火灾现场中多股铜导线熔痕的自动识别,采用主成分分析(PCA)和反向传播(BP)神经网络算法对四种多股铜导线熔痕(一次短路熔痕、二次短路熔痕、过负荷熔痕和火烧熔痕)的金相组织进行了识别研究。利用Image-Pro Plus 6.0和Axio-Imaging软件获取每种熔痕30组17维金相组织参数数据,采用PCA对四种熔痕共120组数据降维,获得前6个主成分得分矩阵,建立具有6个输入层节点,10个隐层节点和4个输出节点的神经网络模式识别模型。随机抽取每种熔痕的20组样品的主成分得分矩阵作为训练集,将每种熔痕的剩余10组主成分得分为测试数据,输入最终训练完成的模型进行识别,其识别准确率达到92.5%。实验结果表明采用PCA+BP神经网络的算法,可以较好地实现多股铜导线熔痕识别,为火灾物证鉴定工作提供了有力的工具。     

基于颗粒流数值方法的岩石压剪破坏细观特征研究

压剪破坏是影响岩体工程安全的主要因素,基于颗粒流程序的伺服控制原理,采用等效晶质模型模拟了粉砂质板岩的压剪破坏过程,通过与室内试验对比验证了其适用性,并从细观角度揭示了岩石在压剪过程中的破坏机理。结果表明:裂纹增长速率与试件压剪过程中经历的弹性、塑性和破坏3个阶段具有相关性;张拉、剪切裂纹呈同步增长趋势,但峰后张拉裂纹增长速率快于剪切裂纹,即试件峰后以张拉破坏为主;随剪切角增大,由沿晶和穿晶断裂向以沿晶断裂为主转变,裂纹数量减小且扩展方向向断裂面集中;穿晶断裂的扩展更容易导致局部失稳,即在宏观上表现为塑性阶段;穿晶裂纹主要沿断裂面扩展、贯通,一定程度上可以抑制断裂面附近较大破裂块体的产生。     

Suppression of flame propagation in a long duct by inertia isolation with inert gases

Experimental studies were done with a small pipe with a diameter of 0.043 m and a large pipe with a diameter of 0.49 m to demonstrate the flame propagation suppression with inertia isolation in a long duct. Tests were carried in an ignition section containing propylene/air mixture near stoichiometric concentration and generating a peak flame propagation speed of approximately 100 m/s. The ignition section is connected to a section filled with an inert gas, another section with flammable mixtures, and finally a sufficiently long, ambient section to accommodate flame propagation. The critical length of the inert gas section required for successful suppression of flame from the igniting the flammable section is found to be 0.6 m for CO₂ and 0.9 m for N₂ in the large pipe and 0.2 m for CO₂ and 0.3 m for N₂ in the small pipe. Additional tests with a 3 m of ignition section and peak flame propagation speed of 225 m/s showed that the critical length for successful suppression by CO₂ is only increased slightly to 0.9 m, confirming that the suppression is a result of inertia isolation rather than inert gas dilution. Finally, application of the results in responding to large-scale leak into a long, underground duct is discussed.