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101.
A field study using 15N was conducted on a Vertisol in semi-arid Morocco to assess the fate and efficiency of fertiliser N split applied to winter wheat (Triticum aestivum L.). Splitting of fertiliser N is highly crucial in semi-arid regions, considering the increased moisture stress towards the end of the growing season. A N fertilisation rate of 100 kg N ha-1 was split according to two schemes: i) 25% at planting, 50% at tillering and 25% at stem elongation; or ii) 50% at tillering and 50% at stem elongation. The application of 100 kg N ha-1increased the vegetative dry matter production with more than 2000 kg dry matter ha-1 in comparison with the control treatment. Nitrogen fertilisation had no significant effect on the grain yield production. Moreover, the 1000 grain weight decreased from 32 to 26 g due to N fertilisation. Total N uptake was about 50 kg N ha-1 higher for the fertilised plants in comparison with the unfertilised plants, but it was not affected by the splitting pattern of the fertiliser N. Recoveries of 15N-labelled fertiliser by the plant (above-ground plant parts plus roots from the upper 20 cm layer) were low (31% and 24% for the 3-split and 2-split application, respectively). More N in the plant was derived from fertiliser when applied early in the growing season than when applied late in the season. About 13% of the N in the plants was derived from the 50 kg N ha-1 at tillering, while only 5% was derived from the N application (50 kg N ha-1) at stem elongation. At harvest, a high residual of fertiliser-derived N was found in the 0–90 cm profile (62% and 72%, for the 3-split and 2-split application, respectively). Less than 10% of the applied N could not be accounted for, the amount being highest for the application at tillering. This N not accounted for was mainly ascribed to denitrification after an important rainfall event. The application of fertiliser N led to an increase of about 20 kg N ha-1 in soil N uptake by the crop (positive ANI). The results suggested a dominant influence of moisture availability on the fertiliser N uptake by wheat. 相似文献
102.
A novel solid state route has been successfully developed for the synthesis of nano-scale hydrous ruthenium oxide (denoted as RuO2·xH2O). The procedure involves directly mixing RuCl2·xH2O with alkali to form RuO2·xH2O in a mortar at room temperature. Transmission electron microscopy (TEM) and N2 adsorption–desorption measurement indicate that the RuO2·xH2O particle is approximately 30–40 nm with mesoporous structure. The crystalline structure and the electrochemical properties of RuO2·xH2O have been systematically explored as a function of annealing temperature. At lower temperatures, the RuO2·xH2O powder was found in an amorphous phase and the maximum capacitance of 655 F g−1 was obtained by annealing at 150 °C. Higher temperatures (exceeding 175 °C) presumably converted amorphous phase into crystalline one and the corresponding specific capacitance dropped rapidly from 547 F g−1 at 175 °C to 87 F g−1 at 400 °C. Also, the dependence of electrochemical performance on annealing conditions of RuO2·xH2O was investigated by electrical impedance spectroscopy (EIS) study. 相似文献
103.
张鹤云 《水科学与工程技术》2012,(2):88-90
对坝体下游坝坡渗水原因进行了分析,比较了振动沉模、劈裂灌浆和深层搅拌连续墙等防渗加固方案,确定采用振动沉模、防渗墙进行防渗处理,阐述了振动沉模防渗墙的设计要点。 相似文献
104.
105.
对涤锦复合分裂丝在纺丝过程中遇到的一些问题进行了分析,并对其工艺进行了调整。指出在该复合分裂丝生产中,纺丝温度及两种熔体流动性能的差异对POY可纺性和产品质量有重大影响。提出了解决办法。 相似文献
106.
107.
J. Yamamatsu N. Kawano T. Arashi A. Sato Y. Nakano T. Nomura 《Journal of power sources》1996,60(2):199-203
The reliability of multilayer ceramic capacitors (MLCCs) with Ni internal electrodes has been studied trom the viewpoint of partial oxygen pressure (PO2) during firing. It is shown that the load-life time of the insulation resistance (1R) was prolonged by firing under low Po2 annealing after firing, and the addition of dopants. It is also shown that the generation of oxygen vacancies led to the degradation of IR. Annealing treatment for the oxidation of the dielectric body accelerates the dielectric aging of MLCCs. It is found that the appropriate control of the PO2 during firing can improve the reliability of MLCCs with Ni electrodes to a level as high as that of MLCCs with precious metal electrodes. Thus, we have developed an MLCC with Ni electrodes that features high reliability and a large capacitance of 10 μF for the Y5V characteristic and 4.7 μF for the X7R characteristic, both in the case of the C3216 (3.2 mm × 1.6 mm × 1.4 mm) form. 相似文献
108.
Effect of treatment of activated carbon fiber cloth electrodes with cold plasma upon performance of electric double-layer capacitors 总被引:4,自引:0,他引:4
Masashi Ishikawa Atsushi Sakamoto Masayuki Monta Yoshiharu Matsuda Koichi Ishida 《Journal of power sources》1996,60(2):233-238
Charge/discharge behavior of electric double-layer capacitors composed of activated carbon fiber cloth (ACFC) electrodes and an organic electrolyte was investigated. The modification of the ACFC electrodes was performed using cold plasma generated in argon-oxygen atmosphere. The effect of the cold plasma treatment of the ACPC electrodes on the capacitor performance was discussed on the basis of the physical and chemical properties of the ACFC surface such as pore radius distribution and surface atom concentration. 相似文献
109.
本文主要介绍梅溪水库大坝进行劈裂灌浆前后运行情况对比及劈裂灌浆对大坝安全运行的作用,同时指出了该水库目前存在的问题,分析了原因,并提出应注意的问题及解决方案。 相似文献
110.
基于故障点位置识别的串补线路距离保护方案 总被引:1,自引:0,他引:1
分析并指出了电平检测方案存在的灵敏度不足的问题。简单介绍了利用保护测量电流、电压计算保护安装处至串补电容之间沿线各点电压的方法,并分别分析了在串补电容前和串补电容后故障以此方法所计算得到的沿线各点电压幅值的特点。在电容前金属性故障时,保护安装处至电容之间将出现电压极小值点,且电压幅值理论上为0;在电容后故障时,计算电压即使出现极值点其幅值也较高。据此提出了串补线路故障点位置识别的方法,结合传统距离保护形成了适用于串补线路的距离保护新方案。该方案能在可靠防止超越的基础上很大程度地提高距离保护的灵敏度。EMTP仿真验证了该方案的有效性和可靠性。 相似文献