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基于DRASTIC模型的地下水脆弱性评价方法评述 总被引:1,自引:0,他引:1
首先分析了基于DRASTIC模型的地下水脆弱性评价方法,然后探讨了该模型的局限性和缺陷,并评述了改进模型的应用效果,最后对基于DRASTIC模型评价方法的应用前景进行了分析,提出了关于选用和应用该模型需要重点关注的问题和评价成果需实现成果价值最大化。 相似文献
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用5×5半双列杂交研究甘蓝型低芥酸油菜单株产量的遗传,结果表明:供试的甘蓝型低芥酸油菜品系中,单株产量的遗传符合加性显性模型,显性性质为超显性,平均显性度为1.404。显性基因约为隐性基因的3倍多,并且多数增效基因表现显性,但也有显性的减效基因存在。单株产量的广义遗传力h_B~2=71.4%,狭义遗传力h_N~2=33.18%。供试亲本显性效应的强弱依次为81007>81006>81018>81004>81033,增效基因的多少依次为81018>81006>81007>81004>81033。一般配合力的大小依次为81018>81006>81004>81033>81007。 相似文献
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采用试管培养法进行松木屑拟菌效果的研究。结果表明,松木屑经自然堆积8个月后,最多可在培养料中添加60%,不明显影响产量满袋时间为58 d,袋单产量42g;碱处理法菌丝生长较好,出耳快,产量与自然堆积法相近。 相似文献
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介绍了现有人造木材的种类,阐述了用竹刨花、竹(木)屑等竹(木)加工剩余物或农作物秸秆与造纸黑液中提取的木质素开发人造木材的重大意义,简要介绍了该人造木材的制造原理和方法以及产品的用途,并分析了人造木材的市场前景及其产业化的可行性。 相似文献
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Muñoz JA Stephen J Baptiste KE Lepage OM 《Veterinary journal (London, England : 1997)》2008,177(2):260-265
The objective of this study was to evaluate the feasibility, efficacy and complications following lavage and drainage of the lateral compartment (LC) of the equine guttural pouch (GP) using a modified Garm's technique (MGT). In an ex vivo study (study 1), six cadaver heads were examined to assess the anatomical limits of the surgical approach and whether vital structures might be damaged. This was followed by an in vivo study (study 2) in which a lavage/drainage tube was placed for 3 days into each LC of four standing horses using the MGT. In both studies, the procedure offered direct access into the LC and indirect access into the medial compartments of the GP. In study 1, the MGT provided a rostroventral point of access allowing drainage of the LC, with no obvious iatrogenic damage. In study 2, the MGT permitted lavage of the entire GP in three healthy horses and one horse with mild GP empyema. The only major complication was development of emphysema of the lateral wall of one LC, with secondary collapse of the mucous membrane. The time for secondary wound healing was 12-14 days. The MGT can be performed safely in standing horses and may be of value in providing access for lavage and drainage in horses with mild GP empyema. 相似文献
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The influence of different preharvest and postharvest factors affecting off-odour development of fresh-cut iceberg lettuce in low-O2 modified atmospheres (MA) was investigated. Fresh-cut iceberg lettuce developed undesirable off-odours under low O2 and elevated CO2 atmospheres. A strong relationship between CO2 concentration and off-odour development was observed. Significant differences in off-odour development existed among different cultivars in two harvests in consecutive years. The influence of maturity stage was evaluated, comparing fresh-cut product from immature and over-mature heads with commercial ones. Higher CO2 concentrations and higher accumulation of ethanol and acetaldehyde were detected in the headspace of MA-packed lettuce from immature heads. Differences in respiration rate of the fresh-cut product from heads cultivated during the winter–spring seasons were around 30%. Respiration rate of fresh-cut iceberg lettuce increased when medium temperature during cultivation increased. Changes in the product weight generated different CO2 levels which correlated with the production of ethanol and acetaldehyde and other off-odour metabolites related with the lipoxygenase (LOX) pathway such as hexanal, 1-hexanol, and cis-3-hexen-1-ol. Volatile compounds such as cis-3-hexen-1-ol, β-elemene, ethyl acetate and dimethyl sulphide increased their content more than 10 times compared with other volatiles. Moreover, differences in the initial flushed gas-mixture with or without CO2 showed higher CO2 concentrations and the development of stronger off-odours when samples were flushed with an enriched CO2 gas-mixture. In summary, visual quality of fresh-cut iceberg lettuce is important but so are odour and flavour. MAP currently used for fresh-cut lettuce may need some modification to inhibit off-odours and achieve better aroma and flavour qualities for preserving “freshness” of the cut product. Screening for cultivars with low browning potential and fermentation, harvested at optimum maturity stage and with an adequate package design are recommended. 相似文献