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571.
为有效预警自然崩落法开采过程中顶板大面积崩落,确定顶板失稳预警期,基于微震、时域反射、钻孔电视等综合监测数据,研究岩体失稳过程点监测数据及微震活动性参数变化特征。结果表明:基于多源参数可有效预警顶板失稳事件,但点监测无法兼顾整个采区顶板,大尺度区域性监测主要依靠微震监测系统;根据顶板失稳事件前后b值、累积视体积、能量指数、施密特数等微震活动性参数变化特征,确定普朗铜矿顶板失稳预警期为24 d。研究结果可为后续整个采区其他区域顶板稳定性监测预警工作提供借鉴。 相似文献
572.
为准确预测煤层气中多组分气体的吸附性能,将空位溶液与Dubinbin-Astakhov(DA)理论相结合,提出1种适用于煤层气吸附系统的多组分混合吸附模型。在模型中,吸附体系被视为气体与假设的“空位溶质”的多元混合物,吸附体系视为气相和吸附相空位溶质之间的平衡。结果表明:根据单组分气体吸附等温线,采用D-A方程计算分析了生成二元(吸附质+空位)混合物中纯组分气体的活度系数,并优化吸附参数;模型能够根据在单一温度下收集的纯组分吸附数据预测不同温度下的多组分气体吸附;模型计算结果与实测结果吻合良好,误差在10%以内,充分说明模型是切实可靠的。 相似文献
573.
Studies of the influence of parasites on host fitness generally conclude that parasites have a strong negative effect on their
hosts. In this study, we have investigated experimentally the role of Polymorphus minutus, an acanthocephalan parasite, on the salinity tolerance of the freshwater amphipod Gammarus roeseli, one of its intermediate hosts. Unexpectedly, P. minutus-infected gammarids were more tolerant to salinity stress than uninfected ones. The mean lethal salt concentrations for 50%
mortality of hosts tested were 17.3 (infected) and 9.7 g/L (uninfected). The parasitic load (one or two parasites per host)
did not affect the result. The size of hosts had no significant influence on the salinity tolerance of either infected or
uninfected gammarids. The mobility of all types of gammarid decreased when the salinity exceeded 9.0 g/L, but there was no
significant difference between infected and uninfected gammarids. We discuss the higher salinity tolerance of infected amphipods
in relation to O2 consumption and osmoregulation. Finally, we demonstrate that the salinity tolerance is enhanced in the parasitized amphipod
but without a significant change in behavior or an osmoregulatory adjustment. 相似文献
574.
The effects of exogenous salicylic acid on growth and H2O2-metabolizing enzymes in rice seedlings under lead stress 总被引:4,自引:0,他引:4
Salicylic acid (SA) was an essential component of the plant resistance to pathogens and also plays an important role in mediating plant response to some abiotic stress. The possible effects of SA on the growth and H2O2-metabolizing enzymes in rice seedlings under lead stress were studied. When rice seedlings grown in nutrient solution containing Pb^2+ (0, 0.05, 0.15, 0.25 mmol/L) for 18 d, the plant biomass as well as the chlorophyll content of leaves decreased with increasing Pb concentration. The pre-treatment with SA (treated with 0.1 mmol/L SA for 48 h before Pb stress) partially protected seedlings from Pb toxicity. The chlorophyll contents were significant higher in leaves of Pb-exposed with SA pre-treatment seedlings than in Pb-exposed plants at the same Pb intensity. SA pre-treated alone could significantly increase the length of shoot and root of seedlings but the vigour difference was not marked under long-term exposure to Pb toxicity. SA pre-treated influence the H2O2 level in leaves of seedlings by up-regulating the activity of superoxide dismutase (SOD), repressing the activity of catalase (CAT) and ascorbate peroxidase (APX) depending on the concentrations of Pb^2+ in the growth medium. The results supported the conclusion that SA played a positive role in rice seedlings against Pb toxicity. 相似文献
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