2 resultados para Teaching performance assessment

em Chinese Academy of Sciences Institutional Repositories Grid Portal


Relevância:

80.00% 80.00%

Publicador:

Resumo:

以发烟硫酸为磺化剂进行磺化反应,制备了石油磺酸盐.通过对原料性质、反应时间、反应温度对产品性能影响的考察,筛选出最佳的实验原料及制备的工艺条件.研究表明,磺化反应条件选取温度为40℃、反应时间为60min时,可以得到性能优良的石油磺酸盐产品.以海洋混合减一线油、辽河减四线油为原料制得的石油磺酸盐产品,提纯后具有较好的表面张力和界面性质.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

For maximizing the effective applications of remote sensing in crop recognition, crop performance assessment and canopy variables estimation at large areas, it is essential to fully understand the spectral response of canopy to crop development and varying growing conditions. In this paper, the spectral properties of winter wheat canopy under different growth stages and different agronomic conditions were investigated at the field level based on reflectance measurements. It was proved that crop growth and development, nitrogen fertilization rates, nutrient deficit (e.g. lacking any kind of nitrogen, phosphorus and kalium fertilizer or lacking all of them), irrigation frequency and plant density had direct influence on canopy reflectance in 400-900 nm which including the visible/near infrared bands, and resulted in great changes of spectral curves. It was suggested that spectral reflectance of crop canopy can well reflect the growth and development of crop and the impacts from various factors, and was feasible to provide vital information for crop monitoring and assessment. ©2010 IEEE.