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大白菜经过大田群体选择优良种株和抗病单株,采用叶芽扦插繁殖,并应用植物激素能促进插枝的生根,提高成活率,提高品种纯度,扩大良种繁殖系数。 相似文献
965.
The stability of the brake system is a key factor for the vehicle safety.It is important for the air braking system's stability to shorten the time lag between the front brake and the rear brake,the reasonable disposal of the air pipeline and the optimization of the braking system design.A test bench is developed to test the performance of the air braking system,which is mainly made of pressure sensors,signal amplifiers,data acquisition system,computer,pressing air resource and so on.Based on this test bench,the reaction time of the system while braking and abandoning brake can be measured.Using this test bench,the performances of the air braking system of a certain commercial vehicle is detected.Compared with the actual road test,it can save the cost and the time for experiment largely. 相似文献
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LYU Wei-Sheng XIAO Fu-Liang ZHANG Shao-Wen ZHENG Wei HUANG Tian-Bao XIAO Xiao-Jun LI Ya-Zhen WU Yan HAN De-Peng XIAO Guo-Bin ZHANG Xue-Kun 《作物学报》1962,46(11):1790-1800
In order to explicit proper sowing and fertilizing methods of rapeseed production in red-soil dryland, a two-year field experiment covering two rapeseed seasons (2017-2018 and 2018-2019) was conducted with four treatments of sowing and fertilizing methods to analyze the impact on yield formation and fertilizer use efficiency of rapeseed, including conventional sowing and fertilizing method (T1), sowing in row with surface broadcast fertilizing (T2), synchronous sowing in uniform row with side deep fertilizing (T3) and synchronous sowing in wide-narrow row with side deep fertilizing (T4). The results were as follows: The yield and fertilizer use efficiency of rapeseed in red-soil dryland were significantly affected by sowing and fertilizing methods. Besides, these differences were more significant in poor soil condition and drought season (2017-2018) than those in nutrient-rich soil condition and rainy season (2018-2019). Compared with T1 and T2, T3 and T4 promoted the yield formation and increased its fertilizer use efficiency significantly, whereas there was no significant difference between T3 and T4. Specifically, the technique of synchronous drilling sowing with side deep fertilizing could improve dry matter production during the whole growth period of rapeseed, especially from anthesis to maturity, with a corresponding rise of dry matter accumulation of both underground and aboveground after anthesis. Meanwhile, compared with the conventional cultivation, the technique of synchronous drilling sowing with side deep fertilizing increased the uptake of nutrients (N, P and K), effective plant density and maintained sufficient pod number, and thus improved the yield and fertilizer use efficiency of rapeseed. This study indicated that the technique of synchronous drilling sowing with side deep fertilizing had the potential of improving rapeseed productivity in red-soil dryland of southern China. Therefore, it should be suggested to promote the application according to local condition. 相似文献
970.
As the development of knowledge economic , human resource has been the core of the world economic .So searching the reasonable evaluating and managing methods becomes one of the hot issues which have been concerned by people . Traditional evaluating methods of human resource are simple and direct , but they greatly depend on people's subjective judgement and experience . In order to overcome the default , this paper puts forward the method of synthetically evaluation on rough sets, which takes advantage of the rough sets theory, the concept of information entropy and relative analysis to filter the original indexes, then to standardize the importance degree of every index and get the weight of every index. Synthetically valuation model and corresponding arithmetic are summed up. Finally the sample illuminates the validity and feasibility of this method. 相似文献