浅析工程渗漏的原因及防治措施

本文对工程中屋面、墙面、卫生间等渗漏的原因进行了详细分析,并提出了相应的防治措施。     

一种油罐底板渗漏的实时监测技术

在油罐渗漏事故中，底板渗漏占的比率最高，渗漏的油水混合物腐蚀能力极强，而一般的检查方法有时很难判断底板是否发生渗漏。通过对油罐底板渗漏及其检测方法的分析，提出了一种实时监测油罐底板渗漏的技术——油罐基础检漏层技术，介绍了油罐基础检漏层的结构原理、设计计算及安装注意事项。     

电导法测定西洋梨的抗寒性研究

以1a生枝条为试材,对6个西洋梨品种进行了电解质渗出率测定,应用 Logistic 方程建立回归模型;确定半致死温度在低温持续24 h为-23.42～-26.86℃;48 h为-27.32～-33.21℃;72 h为-28.27～-32.23℃之间,6个西洋梨的抗寒性由强到弱依次为:八月红＞巴梨＞早巴梨＞红巴梨＞五九香＞红安久;相关系数介于0.9527～0.9909之间,表明不同低温持续时间的电解质渗出率遵循 Logistic 方程的变化规律,且与半致死温度呈线性关系.     

Effects of fusaric acid on cells from tomato cultivars resistant or susceptible toFusarium oxysporum f. sp.Lycopersici

Cell suspension cultures were set up from two tomato cultivars, one resistant, (Rio grande) and one susceptible (63.5) toFusarium oxysporum f. sp.lycopersici. Growth rates of the two cell cultures were comparable. Toxicity of fusaric acid, expressed as the fresh weight loss, was analyzed: It was significant in both cases after 10 h, but toxicity was twice as high for 63.5 suspension cells. In the same way, electrolyte leakage caused by fusaric acid was three times more important for 63.5 suspension cells. Moreover, fusaric acid treatment resulted in an acidification of the extracellular medium for 63.5 suspension cells (0.4 pH unit), whereas an alkalization was observed for Rio grande suspension cells (0.2 pH unit). Preliminary experiments suggest that fusaric acid was partially metabolized by Rio grande suspension cells, however, no detoxified forms of fusaric acid were detected either in cells or in culture filtrates. For these two tomato cultivars, the differences in sensitivity to fusaric acid of cultivated cells correspond to the differences in plant susceptibility toFusarium oxysporum f. sp.lycopersici.Abbreviations BAP 6-benzylaminopurine - conductivity - 2,4-D 2,4-dichlorophenoxyacetic acid - EtOAc ethyl acetate - FA fusaric acid - resistivity     

Effects of pure plant secondary metabolites on methane production,rumen fermentation and rumen bacteria populations in vitro

In this study, the effects of seven pure plant secondary metabolites (PSM s) on rumen fermentation, methane (CH₄) production and rumen bacterial community composition were determined. Two in vitro trials were conducted. In trial 1, nine concentrations of 8‐hydroxyquinoline, α‐ terpineol, camphor, bornyl acetate, α‐ pinene, thymoquinone and thymol were incubated on separate days using in vitro 24‐hr batch incubations. All compounds tested demonstrated the ability to alter rumen fermentation parameters and decrease CH₄ production. However, effective concentrations differed among individual PSM s. The lowest concentrations that reduced (p  <  .05) CH₄ production were as follows: 8 mg/L of 8‐hydroxyquinoline, 120 mg/L of thymoquinone, 240 mg/L of thymol and 480 mg/L of α‐ terpineol, camphor, bornyl acetate and α‐ pinene. These concentrations were selected for use in trial 2. In trial 2, PSM s were incubated in one run. Methane was decreased (p  <  .05) by all PSM s at selected concentrations. However, only 8‐hydroxyquinoline, bornyl acetate and thymoquinone decreased (p  <  .05) CH₄ relative to volatile fatty acids (VFA s). Based on denaturing gradient gel electrophoresis analysis, different PSM s changed the composition of bacterial communities to different extents. As revealed by Ion Torrent sequencing, the effects of PSM s on relative abundance were most pronounced in the predominant families, especially in Lachnospiraceae , Succinivibrionaceae , Prevotellaceae , unclassified Clostridiales and Ruminococcaceae . The CH ₄ production was correlated negatively (?.72; p  <  .05) with relative abundance of Succinivibrionaceae and positively with relative abundance of Ruminococcaceae (.86; p  <  .05). In summary, this study identified three pure PSM s (8hydroxyquinoline, bornyl acetate and thymoquinone) with potentially promising effects on rumen CH₄ production. The PSM s tested in this study demonstrated considerable impact on rumen bacterial communities even at the lowest concentrations that decreased CH₄ production. The findings from this study may help to elucidate how PSM s affect rumen bacterial fermentation.     

二塘沟水库右坝肩工程地质问题初步探讨分析

【目的】通过现场试验、测试,对二塘沟水库右坝肩主要工程地质问题进行准确评价分析,为设计提供合理的地质参数和建议。【方法】以二塘沟水库右岸坝肩区为主要研究对象,进行现场岩石鉴定试验,钻孔压水试验,平洞岩石构造观测试验,室内岩石化学成分分析试验等。【结果】二塘沟水库右岸地形较为陡峭,岩性主要为层状凝灰岩夹凝灰质砂岩和砂岩。水库右坝肩整体构造发育:岩体完整性较差,靠近断层附近透水性和深度较大。据钻孔和平洞揭露,岩体强风化层厚2～3m,岩体较破碎。据钻孔水质分析得知,右岸地下水硫酸根离子含量514.37mg/L,具有结晶类硫酸盐型腐蚀性。【结论】二塘沟水库右坝肩岩体存在较深和较长的中等透水带、裂隙密集带和断层破碎带岩石碎屑水溶盐含量较高,岩体和地下水中硫酸盐对混凝土存在腐蚀性问题。     

离子束介导技术在水稻遗传改良中的应用前景

在利用离子束介导技术对水稻进行遗传改良的研究领域内仍然存在着5大研究难题值得注意,即离子束介导试验的机理问题、供体与受体的亲缘关系、对介导试验的后效性研究、寻找介导试验证据时的片面性和离子束介导技术的超前性研究.明确提出了离子束介导技术在水稻遗传改良中的技术思路,即立足于离子束介导技术这一物理学技术平台、注重研究2个关键性问题、在研究中完成3个有效转变、寻找4个方面的试验证据、研究5大生物学特性.     

Cytoplasmic and nuclear genetic components of membrane stability of winter wheat plants exposed to sub‐zero temperatures

Winter wheat (Triticum aestivum L.) is seeded in the autumn and harvested the following summer, and therefore, must survive multiple episodes of subfreezing temperatures throughout the winter months. Cellular membrane stability following exposure to subfreezing temperatures contributes to the ability to survive these episodes. This study investigated the inheritance of the ability to tolerate subfreezing temperatures with a seven‐parent diallel cross analysis of cellular membrane integrity as measured by electrolyte leakage after exposure to ?10 or ?14 °C. Significant differences in membrane stability were found among the parent lines. The inheritance of the freezing tolerance as measured by electrolyte leakage was complex and characterized by significant additive, dominant and cytoplasmic effects. General combining ability, indicative of additive genetic effects, were significant at both test temperatures, but accounted for 25.5% of the variance at the ?10° C test temperature, and only 4% of the variance at the ?14 °C test temperature. Specific combining ability, indicative of genetic dominance effects, were significant at both test temperatures, but accounted for only 14.6% of the variance at the ?10 °C test temperature, and 38% of the variance at the ?14 °C test temperature. Reciprocal (cytoplasmic) effects were significant and accounted for about 20% of the variance at both test temperatures. Cytoplasmic effects contributing to greater membrane stability were especially apparent in the cultivar Tiber when crossed to Masami, Lewjain, or Hatton. These results suggest that efforts to improve freezing tolerance are complicated by differing gene action at different test temperatures and also may benefit from identifying specific combinations of nuclear and cytoplasm sources that are most conducive to membrane stability following freezing.     

国产海雀稗种质资源抗寒性鉴定

采用叶片电解质外渗法和匍匐茎恢复生长试验法,对37份国产海雀稗种质资源和6份海雀稗引进品种进行抗寒性鉴定。电解质渗出率测定结果表明,在0~-8℃之间的低温胁迫下,随着温度的降低,电解质渗出率快速地升高;在-8~-12℃之间,电解质渗出率上升比较缓慢,在-12~-16℃之间,上升非常缓慢,逐渐趋于稳定。不同材料间的抗寒性LT50存在较大的遗传变异,变异范围为-0.09~-7.24℃,国产海雀稗种质资源中P049、P042、P013、P018-2和P058的LT50低于-5℃,其中P049的LT_(50)最低(-7.24℃),低于所有引进的对照品种。匍匐茎恢复试验的测定结果表明,-16℃低温胁迫后,所有参试材料都不能恢复生长。0~-12℃低温处理后,不同材料的恢复生长能力也存在较大的遗传变异,总萌芽率的变异范围为10%~46.7%。其中P055(1)在0~-12℃低温处理后都能恢复,抗寒性最好;其次为P033,在0~-8℃均可以恢复,且恢复生长率均在75%以上,总萌芽率最高。P055(1)和P033的恢复生长百分率高于所有引进对照品种。     

农田灌溉渠道防渗思考

为了解决传统渠道输水带来的水资源浪费和生态环境破坏的现状,提出了一些关于如何减少农田灌溉渠道渗漏问题的方法,希望能对读者有所帮助。