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981.
非煤矿山是指开采金属矿石、放射性矿石以及作为石油化工原料、建筑材料、辅助原料、耐火材料及其他非金属矿物(煤炭除外)的矿山。大多数矿山企业的生产规模较小,技术装备水平不高,作业环境相对较差,伤亡事故时有发生。 相似文献
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在制备高硅含量原料的碱法蒸煮液时,把一种主要成份为氧化铝的除硅剂加到配碱槽内(或直接加到蒸煮锅内),通过蒸煮,该除硅剂能与原料中硅生成不溶物附着在浆料上,达到降低黑液硅含量的目的。此方法适用于各种碱法制浆过程,对于麦草硫酸盐法,除硅剂用量为原料的2.5%时,黑液除硅率可达到90%以上。通过18×40m3蒸球的中型试验证实,本方法不仅能有效地除硅;还能显著地改善黑液有关蒸发、燃烧的粘度和膨润容积系数(VIE)等理化性质,且对浆料质量及后续制浆、造纸操作无不良影响,对实现稻、麦草碱回收有十分重要的现实意义。 相似文献
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Venable DL Flores-Martinez A Muller-Landau HC Barron-Gafford G Becerra JX 《Ecology》2008,89(8):2218-2227
We quantified seed dispersal in a guild of Sonoran Desert winter desert annuals at a protected natural field site in Tucson, Arizona, USA. Seed production was suppressed under shrub canopies, in the open areas between shrubs, or both by applying an herbicide prior to seed set in large, randomly assigned removal plots (10-30 m diameter). Seedlings were censused along transects crossing the reproductive suppression borders shortly after germination. Dispersal kernels were estimated for Pectocarya recurvata and Schismus barbatus from the change in seedling densities with distance from these borders via inverse modeling. Estimated dispersal distances were short, with most seeds traveling less than a meter. The adhesive seeds of P. recurvata went farther than the small S. barbatus seeds, which have no obvious dispersal adaptation. Seeds dispersed farther downslope than upslope and farther when dispersing into open areas than when dispersing into shrubs. Dispersal distances were short relative to the pattern of spatial heterogeneity created by the shrub and open space mosaic. This suggests that dispersal could contribute to local population buildup, possibly facilitating species coexistence. Overall, these results support the hypothesis that escape in time via delayed germination is likely to be more important for desert annuals than escape in space. 相似文献
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In this article we extend the recent literature on overlapping generations and pollution by allowing generations to perceive the level of pollution differently than the actual level of pollution. We call this pollution perception. Pollution perception can visualize itself as either a concern for the flow of pollution only, or for the stock, or a combination of both. We derive this extension based on empirical evidence from recent advances in behavioural economics.Pollution perception has not only significant consequences for the steady state levels of pollution and capital, but we also find a qualitative change in the dynamics from similar models without pollution perception [A. John, R. Pecchenino, An overlapping generations model of growth and the environment, Econ. J. 104 (1994) 1393–1410]. Specifically, we derive optimal non-linear dynamics through complex eigenvalues and Hopf or Flip bifurcations for a large set of parameters. This leads to violations of two standard criteria of sustainability, suggesting that pollution perception can be another source of intergenerational inequity. 相似文献