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91.
92.
蒸发油气回收技术的研究 总被引:20,自引:2,他引:18
介绍了几种常见的油气分离回收方法及该项目研究的同状与重点,探讨了油气吸收分离回收技术,指出常压常温吸收法宜作为吸收法的主要研究开发方案,并以适宜油气吸收剂的筛选作为研究的发出点。 相似文献
93.
介绍了油罐气微压自控回收装置的研制过程及其应用。该装置在各个油田的运行实践证明,其具有流程简单、自控程度高、维修方便、运行平稳、安全可靠等优点。该装置的研制成功,解决了油气处理、储存及转输生产过程中的油气挥发损耗问题,节约了能源,减少了环境污染,取得了显著的经济效益和社会效益。 相似文献
94.
A field trial was carried out to study the nitrogen fertilizer recovery by four crops in succession in manurial loess soil in Yangling. The results showed that the nitrogen fertilizer not only had the significant effects on the first crop , but also had longer residual effects, even on the fourth crop. The average apparent nitrogen fertilizer recovery by the first crop was 31.7%, and the accumulative nitrogen recovery by the 4 crops was high as 62.3%, and the latter was double as the former. It is quite clear that the nitrogen fertilizer recovery by the first crop was not reliable for estimating the nitrogen fertilizer unless the residual effect of nitrogen fertilizer was included. 相似文献
95.
退化羊草草地生态恢复技术的研究 总被引:7,自引:0,他引:7
在内蒙古锡林郭勒盟东乌珠穆沁旗对退化羊草草地进行了更新复壮的技术研究,初步探索出了退化羊草草地生态恢复技术和群落演替规律。 相似文献
96.
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99.
Effect of Different Crop Densities of Winter Wheat on Recovery of Nitrogen in Crop and Soil within the Growth Period 总被引:2,自引:0,他引:2
Previous experiments have shown that, at harvest of winter wheat, recovery of fertilizer N applied in early spring [tillering, Zadok’s growth stage (GS) 25] is lower than that of N applied later in the growth period. This can be explained by losses and immobilization of N, which might be higher between GS 25 and stem elongation (GS 31). It was hypothesized that a higher crop density (i.e. more plants per unit area) results in an increased uptake of fertilizer N applied at GS 25, so that less fertilizer N is subject to losses and immobilization. Different crop densities of winter wheat at GS 25 were established by sowing densities of 100 seeds m–2 (Slow), 375 seeds m–2 (Scfp= common farming practice) and 650 seeds m–2 (Shigh) in autumn. The effect of sowing density on crop N uptake and apparent fertilizer N recovery (aFNrec = N in fertilized treatments ? N in unfertilized treatments) in crops and soil mineral N (Nmin), as well as on lost and immobilized N (i.e. non‐recovered N = N rate ? aFNrec), was investigated for two periods after N application at GS 25 [i.e. from GS 25 to 15 days later (GS 25 + 15d), and from GS 25 + 15d to GS 31] and in a third period between GS 31 and harvest (i.e. after second and third N applications). Fertilizer N rates varied at GS 25 (0, 43 and 103 kg N ha–1), GS 31 (0 and 30 kg N ha–1) and ear emergence (0, 30 and 60 kg ha–1). At GS 25 + 15d, non‐recovered N was highest (up to 33 kg N ha–1 and up to 74 kg N ha–1 at N rates of 43 and 103 kg N ha–1, respectively) due to low crop N uptake after the first N dressing. Non‐recovered N was not affected by sowing density. Re‐mineralization during later growth stages indicated that non‐recovered N had been immobilized. N uptake rates from the second and third N applications were lowest for Slow, so non‐recovered N at harvest was highest for Slow. Although non‐recovered N was similar for Scfp and Shigh, the highest grain yields were found at Scfp and N dressings of 43 + 30 + 60 kg N ha–1. This combination of sowing density and N rates was the closest to common farming practice. Grain yields were lower for Shigh than for Scfp, presumably due to high competition between plants for nutrients and water. In conclusion, reducing or increasing sowing density compared to Scfp did not reduce immobilization (and losses) of fertilizer N and did not result in increased fertilizer N use efficiency or grain yields. 相似文献
100.
本研究以半年生翠云草盆栽为试验材料,研究不同遮荫处理对翠云草叶色变化的影响。试验设置全光照R0(透光率100%NS)、一层遮荫R1(38%NS)、二层遮荫R2(20%NS)、三层遮荫R3(16%NS)和四层遮荫R4(10%NS)共5个处理。处理3个月后,比较叶片中叶绿素a、叶绿素b、叶绿素a+b、叶绿素a/b、类胡萝卜素、花色素苷、苯丙氨酸解氨酶及可溶性糖含量变化。结果显示,叶绿素含量在3层遮荫处理下最高,叶片表现出特殊的蓝绿色;全光照下,叶绿素含量和花色素苷含量均最低,而类胡萝卜素含量最高,说明叶片受到强光胁迫,是类胡萝卜素而不是花色素苷取代了那部分被破坏的叶绿素,因此叶片表现出红色。方差分析表明,不同遮荫处理对翠云草叶片中叶绿素含量影响极显著,对花色素苷含量影响显著,而对类胡萝卜素含量影响不显著。掌握翠云草叶色在不同遮荫条件下的变化规律,有助于在园林中根据景观需要进行合理配置,创造别具特色的园林植物景观。 相似文献