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芭蕉科芭蕉属植物成分及其活性 总被引:1,自引:0,他引:1
对芭蕉科芭蕉属植物(Musa)中分离得到的化学成分和生物活性研究现状进行了综述。目前报道本属植物中主要是酚性成分,尤以phenylphenalenone类成分为主,该类成分大都具有生物活性。对该属植物化学成分研究现状进行文献调研,对合理开发和利用该属植物具有非常重要的参考价值。 相似文献
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刺桐属植物富含刺桐碱、黄酮、萜类及其他酚类等具有优良生物活性的天然物质,所以刺桐属植物天然成分的提取、表征工作一直备受科研工作者青睐。将对近年来刺桐属植物天然成分提取的研究进展进行综述,为研究刺桐属天然成分的科研工作者和天然药物开发提供重要参考。 相似文献
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为获取长白松的热解特性,预防森林火灾发生,以长白松的树枝、球果、树皮和松针作为研究对象进行热解过程分析,并采用Coats-Redfern法进行热解动力学分析,以球果为研究对象探究各种因素对长白松热解的影响。实验结果表明:4种材料的热解过程均可分为4个阶段,其中主要失重阶段的质量损失率为60%左右。升温速率越大,热解越不充分,并且存在热滞后现象,25℃/min时质量损失率最小(80.34%);粒径大小对TG、DTG曲线影响较小,粒径越小,内外部受热更均匀,因此0.20 mm粒径的材料质量损失率最大(91.18%);氮气气氛下主要失重阶段有一个失重峰,而在高纯空气气氛下有两个失重峰,且长白松球果在高纯空气中热解时间更长,热解更充分,促进作用更强,质量损失率为98.14%。热解动力学分析结果显示:4种材料的最佳机理函数为“三维扩散”,活化能最大的是树枝(157.04 kJ/mol),最小的是松针(98.19 kJ/mol),球果的活化能为148.08 kJ/mol,树皮的活化能为115.04 kJ/mol,因此,要格外注意对松针和树皮的防火工作。 相似文献
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F. Martin Wilt Glenn C. Miller Richard L. Everett Murray Hackett 《Journal of chemical ecology》1993,19(2):185-194
Senescent foliage from pines is potentially a large contributor to the total monoterpene content of the litter layer, and the availability of these compounds as phytotoxins may result from release of these compounds into the vapor phase. In order to determine the fate of several monoterpene hydrocarbons in the natural environment, we examined their concentrations in fresh, senescent, and decaying needles from 32 single-leaf pinyon pine (Pinus monophylla Torr. & Frem.: Pinaceae) trees growing at two different locations. Total monoterpene content was highest in the fresh needles (mean=5.6 ± 2.2 mg/g extracted air dry weight), but also remained relatively high in senescent needles (mean=3.6 ±1.8 mg/g extracted air dry weight), either still attached to the tree or forming the freshest layer of understory litter. Decaying needles within a dark decomposing layer of litter material 5–20 cm from the surface were found to contain much lower amounts of total monoterpenes (average: =0.12 ±0.06 mg/g extracted air dry weight). Further investigation of the fate of these compounds in the pinyon understory is required to determine if these hydrocarbons are indeed exerting phytotoxic characteristics. 相似文献
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本研究将一种营养型增脂剂施用于云南松, 检测其增脂效果及其对松针生理指标的影响, 结果表明: 5~10月份施加增脂剂后, 云南松增脂率最高可达41.08%, 平均增脂率34.76%。云南松松针鲜质量、干质量、叶绿素总量和可溶性蛋白均有所增加, 最高分别可增加11.02%、10.26%、13.03%和40.96%;松针细胞三大保护酶超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性也有所增加, 从而增加了云南松的抗逆性; 松针中丙二醛(MDA)含量和相对电导率减少, 增加了细胞内膜系统的稳定性, 提高云南松抵御逆境的能力。 相似文献
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The unusual occurrence of 14-methylhexadecanoic acid in pinaceae seed oils among plants 总被引:1,自引:0,他引:1
14-Methylhexadecanoic (14-MHD) acid has been identified in a sample of pine seed oil (Pinus contorta) by gas-liquid chromatography-mass spectrometry of its picolinyl ester derivative: Its identification (through its equivalent
chain length) and its distribution in four conifer families have been checked. It occurred only in Pinaceae, where it was
found in 72 species belonging to the genera Pinus, Abies, Cedrus, Tsuga, Pseudotsuga, Larix, and Picea, in the range 0.02–1.15%. 14-MHD acid could not be detected in the lipids of Taxaceae (Taxus baccata), Cupressaceae (Juniperus communis), or Taxodiaceae (Sciadopytis verticillata), even after a 10-fold concentration of the saturated acid fraction isolated by argentation thinlayer chromatography. It
is concluded that Pinaceae, along with Ginkgo biloba seed lipids, are major exceptions in the plant kingdom with regard to 14-MHD acid, which otherwise occurs almost exclusively
in lipids of animals and microorganisms. The biosynthesis and metabolic role of 14-MHD acid, which other-wise also occur in
wood and leaf lipids, remain unknown. 相似文献
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当前灰霾等大气污染问题备受关注,高效、廉价的催化净化材料作为污染治理技术的核心之一,其研发意义非凡。以柔性材料为基底制备的新型整体式催化剂因催化活性高、加工成型简单、应用灵活、易于实现催化剂原位再生等优点,成为环境催化领域发展的一个新兴热点方向。本文介绍了以金属泡沫、有机泡沫以及纤维等柔性材料为载体的催化剂特性和应用领域,重点阐述了上述柔性负载型催化剂的典型合成过程及其对气态污染物(如NOx、甲苯、甲醛等)的催化性能和净化机制,综述了其在脱硝领域的应用研究成果,包括抗硫耐水机理、纤维滤布催化剂的协同除尘脱硝能力以及碳泡沫催化剂的高效催化性能等。通过总结分析柔性负载型催化剂阶段性研究成果、应用现状以及实际应用问题,进一步展望其在环境催化净化领域的研究方向、重点和难点。催化剂黏结性、活性、稳定性的提升以及移动床反应器-催化剂的匹配设计与优化都将是柔性高效一体式催化剂的研发重心所在,此类催化剂的成功研发将会为中小型燃煤炉窖尾气的催化净化提供技术核心与保障。 相似文献
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Experimental study on the burning behaviour of Pinus halepensis needles using small‐scale fire calorimetry of live,aged and dead samples 下载免费PDF全文
Limited research has been conducted on the burning characteristics of live fuels, which are commonly assumed to behave like moist dead fuels. We use small‐scale laboratory calorimetric experiments to investigate the differences in fire dynamics between live and dead Pinus halepensis needles. The study includes laboratory‐aged samples and different moisture conditions (fresh or oven dry). A series of ten fire behaviour parameters are extracted from the measurements to identify and quantify differences. The main parameters are the following: time to ignition; flaming time; mass loss pre‐ignition, during flaming, and during smouldering; peak power; effective heat of combustion; mean and peak CO/CO2; and radiative fraction. Using these parameters, we show that the most flammable samples are fresh dead and aged needles, followed by dry dead and dry live needles. The least flammable is fresh live needles. Live needles ignite about four times slower, and burn with ~60% lower power and ~50% lower heat of combustion than dead needles. Aged needles resemble most closely the behaviour of dead needles, but many fire behaviour parameters were significantly different. The results confirm the importance of moisture content in the burning behaviour of pine needles, but the differences between live and dead samples cannot be explained solely in terms of moisture but require consideration of plant chemistry and sample drying. © 2015 The Authors. Fire and Materials published by John Wiley & Sons Ltd. 相似文献