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51.
王凡喜 《油气储运》1997,16(8):56-57
汽油在长途运输,长期储存及多次换装过程中。个别质量指标会发生变化,如汽油的馏程发生变化,辛烷值降低及实际胶质含量增多等,在使用中应特别注意,汽油在长期储存过程中应注意1减少轻组分的蒸发和延缓氧化变质;2.饱和储存,减少气体空间;3.避免与铜或其它金属接触;4.防止不杂对油品的污染;5.坚持储存化验,建立汽油质量档案。  相似文献   
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本文通过对桥梁结构物中钢筋锈蚀的分析,来评定桥梁结构中钢筋的使用状态,为准确鉴定旧桥的质量与可靠度提供技术数据。  相似文献   
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SMA应用时必须根据具体情况对其构成进行调整。本文根据钢桥的特殊要求,对SMA在钢箱梁桥桥面铺装中的使用进行了有益的研究。  相似文献   
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30头新生荷斯坦奶公犊出生日期和体重相近,随机分成6组,对照组按常规饲喂鲜牛奶,60日龄断奶;各试验组分别于10、20、30、40和50日龄断奶,试验期为60d。结果表明:试验结束时,20日龄断奶组、30日龄断奶组的体重、平均日增重均显著高于对照组,40日龄断奶组、50日龄断奶组与对照组间无明显差异;各试验组犊牛与对照组在体长和体斜长上无显著差异。  相似文献   
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Genetic mapping of loci determining long glumes in the genus Triticum   总被引:1,自引:0,他引:1  
Elongated glumes are present in thetetraploid wheat species T.polonicum, T. turanicum, T.durum convar. falcatum and in thehexaploid species T. petropavlovskyi.Inheritance of glume length was studiedwith the aim to map the respective lociusing wheat microsatellite markers. In T. polonicum and T. petropavlovskyiloci conferring long glume were mapped nearthe centromere on chromosome 7A. These twoloci are designated P-A pol 1 andP-A pet 1, respectively. It isshown that both are probably homoeoallelicto each other and to the P gene ofT. ispahanicum on chromosome 7B. The loci determining elongated glumes in T. turanicum and T. durum conv. falcatum are not homoeologous to the P loci in the centromeric region of thegroup 7 chromosomes.  相似文献   
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Extreme drought events can directly decrease productivity in perennial grasslands. However, for rhizomatous perennial grasses it remains unknown how drought events influence the belowground bud bank which determines future productivity. Ninety‐day‐long drought events imposed on Leymus chinensis, a rhizomatous perennial grass, caused a 41% decrease in the aboveground biomass and a 28% decrease in belowground biomass. Aboveground biomass decreased due to decrease in both the parent and the daughter shoot biomass. The decreases in daughter shoot biomass were due to reductions in both the shoot number and each individual shoot weight. Most importantly, drought decreased the bud bank density by 56%. In addition, drought induced a bud allocation change that decreased by 41% the proportion of buds that developed into shoots and a 41% increase in the buds that developed into rhizomes. Above results were supported by our field experiment with watering treatments. Thus, a 90‐day‐long summer drought event decreases not only current productivity but also future productivity, because the drought reduces the absolute bud number. However, plasticity in plant development does partly compensate for this reduction in bud number by increasing bud development into rhizomes, which increases the relative allocation of buds into future shoots, at the cost of a decrease in current shoots.  相似文献   
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Finger millet [Eleusine coracana (L.) Gaertn.] is an important coarse cereal crop grown in the arid and semi‐arid regions and often experiences high temperature (HT) stress. The objectives of this research were (i) to quantify effects of season‐long HT stress on physiological and yield traits, (ii) to identify the developmental stages most sensitive to HT stress and (iii) to quantify the genetic variability for HT stress tolerance in finger millet. Research was conducted in controlled environment conditions. HT stress decreased the chlorophyll index, photosystem II activity, grain yield and harvest index. Maximum decrease in number of seeds per panicle and grain yield per plant was observed when stress was imposed during booting, panicle emergence or flowering stages. Maximum genotypic variation was explained by panicle width and number of seeds per panicle at optimum temperature (OT) and grain yield per plant at HT and number of seeds at HT. Based on the stress response and grain yield, tolerant or susceptible genotypes were identified. Finger millet is sensitive to HT stress during reproductive stages, and there was genotypic variability among the finger millet genotypes for number of seeds per panicle and grain yield under HT, which can be exploited to enhance stress tolerance.  相似文献   
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