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Chen Gang 《中国海洋大学学报(自然科学版)》2000,30(Z1):19-24
以CTAB法提取含有番茄黄化曲叶病毒TYLCV-CHI病原的烟草曲 叶病烟草DNA为模板,扩增该病毒外壳蛋白启动子序列,克隆到pGEM7Z载体上,在启动子下 游连接上能表达毒素蛋白的RNase基因和终止子NOS,最终将构建的基因转移到带有绿色荧光 蛋白GFP的植物表达载体上,构建了通过病毒侵染后激发病毒外壳蛋白启动子从而表达毒素 基因,产生毒素杀死病毒防止感染继续扩散的自我保护机制的基因工程植物表达载体。 相似文献
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大牛地气田低电阻率-高声波时差气层的形成与分布 总被引：1，自引：1，他引：0
大牛地气田下石盒子组的盒2、3段具有3种类型的气层,即正常Ⅰ型气层（具有高电阻率和相对较低的声波时差）、Ⅱ型低电阻率-高声波时差气层和Ⅲ型低密度气层。其中前两类气层主要为高产气层。以岩心分析化验资料、常规测井资料、特殊测井资料结合其他地质研究资料,分析了Ⅱ型低电阻率-高声波时差气层的成因。研究结果表明,微裂缝和好的储层物性引起的泥浆侵入,储层微孔喉发育引起的束缚水饱和度增大以及绿泥石黏土矿物包壳等因素是形成这类气层的主要原因,其中微裂缝是主要成因。结合裂缝预测成果,进一步验证了这类气层在平面上的分布。 相似文献
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ＯＮＴＨＥＰＲＥＤＩＣＴＩＯＮＯＦＴＲＡＮＳＩＥＮＴＢＥＤＬＥＶＥＬＳＤＵＥＴＯＡＧＧＲＡＤＡＴＩＯＮＡＮＤＤＥＧＲＡＤＡＴＩＯＮＩＮＣＬＵＤＩＮＧＡＲＭＯＵＲＩＮＧＡ．Ｂ．ＰＡＬＡＮＩＡＰＰＡＮ１,Ｒ．Ｊ．ＧＡＲＤＥ２ａｎｄＰ．Ｎ．ＧＯＤＢＯＬＥ３... 相似文献
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Demel Teketay 《Journal of Arid Environments》1998,38(4):551-560
Seeds ofAcacia origena,A. pilispinaandPterolobium stellatumhave a hard seed coat that hampers imbibition of water and prevents maximum, uniform and rapid germination. Therefore, the seeds were subjected to different treatments involving mechanical scarification, concentrated sulphuric acid and boiling water to break the dormancy imposed by the hard seed coat. To determine the effects of different constant temperature regimes on germination, scarified seeds were incubated on a thermogradient at 10, 15, 20, 25 and 30°C. Germination of scarified seeds was also tested in light and dark. Mechanical scarification resulted in 100% germination for theAcaciaspecies and 94% forP. stellatum. ForA. origena, sulphuric acid treatments for 60, 90 and 120 min resulted in significantly higher per cent germination (>95%) than all the other treatments. ForA. pilispina, sulphuric acid treatments for 45 and 60 min, as well as immersing seeds for 1 min in hot water, gave significantly higher per cent germination (97%) than all the other treatments. ForP. stellatum, mechanical scarification and all the acid treatments applied resulted in significantly higher per cent germination (>85%) than the control and all hot water treatments. All seeds ofP. stellatumimmersed in hot water, even for 1 min, rotted soon after sowing, indicating that they are sensitive to high temperatures. Scarified seeds of the twoAcaciaspecies germinated to a higher degree (≥90%) between 10 and 30°C, while germination of scarified seeds ofP. stellatumranged from 48 to 82% between 10 and 30°C. Scarified seeds of the three species germinated to a large extent (>70%) both in light and dark, indicating that seeds do not require light for germination. 相似文献
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钢结构是现代建筑工程中较普遍的结构形式之一,具备重量轻、机械性能好、可承受较大的荷载及制作和安装机械化程度高的特点。随着城市规模的发展,钢结构在我国建筑业具有非常广阔的应用前景。但由于其自身抗火能力差,在火灾高温作用下,其力学性能如屈服强度、弹性模量等会随温度升高而降低,一般在15min左右即丧失承重能力而垮塌,需采取保护措施使其温度不超过临界点才能在火灾中保持稳定性。涂敷钢结构防火涂料,施工简单、重量轻、耐火时间长且不受钢结构几何形状的制约,具有良好的经济性和实用性。随着环保意识的增强,国内外越来越多的建筑提倡绿色环保理念,参与三星或LEED认证体系的评级认证。水性膨胀型防火涂料凭借其优异的环保、施工安全和防火性能,开始逐渐受到众多业主和设计师的青睐。本文从防火原理、技术特点、防火领域的国内外认证、施工和质量管理的角度,浅谈水性膨胀型防火涂料的性能和发展现状,同时也讨论了目前防火涂料存在的一些问题。 相似文献
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Luke J. Wooldridge Richard H. Worden Joshua Griffiths James E. P. Utley 《Sedimentology》2019,66(3):1118-1138
The specific mineralogy of clay grain coats controls the ability of the coat to inhibit quartz cementation in sandstones during prolonged burial and heating. How and why clay‐coat mineralogy varies across marginal marine systems is poorly understood, even though these eogenetic phenomena strongly influence subsequent mesodiagenesis and reservoir quality. The novel development of the ability to predict the distribution of clay‐coat mineralogy would represent an important development for sandstone reservoir quality prediction. In marginal marine sediments, clay minerals occur as grain‐coats, floccules, mud intraclasts, clay‐rich rock fragments or as dispersed material. However, the relationships between clay mineralogy, the amount of clay, and its distribution is poorly understood. This study focused on the Ravenglass Estuary, UK. The key aim was to develop and apply a novel methodology utilising scanning electron microscope – energy dispersive spectrometry, for the first time, on grain coats in modern sediments, to differentiate the clay‐coat mineral signature from that of the bulk sediment, and reveal the distribution of clay minerals across marginal marine sediments. The study showed that marginal marine sediments principally have their clay mineral assemblage present as clay‐coats on sand grains. These clay‐coats have a mixed clay mineralogy and are spatially heterogeneous across the range of marginal‐marine depositional environments. The study further showed that clay‐coat mineralogy is governed initially by the hydrologically‐controlled segregation of the clay minerals within inner estuarine depositional environments, and subsequently by the selective abrasive removal of specific clay mineral types during reworking and transport into the outer estuary and the marine environment. The highest relative abundance of grain‐coating chlorite was in sand‐flat and tidal‐bar depositional environments. The availability of an analogue data set, and an understanding of the controlling processes of clay‐coat mineralogy, offer crucial steps in building a predictive capability for clay‐coat derived elevated reservoir quality in deeply buried sandstones. 相似文献
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