浅谈2,4-滴丁酯飘移药害

2,4-滴丁酯是目前防除鸭跖草(俗称兰花菜)的有效药剂,广泛用于玉米、大豆播后苗前土壤封闭,也可用于玉米田苗后早期茎叶处理。     

Attenuation correction of L-shell X-ray fluorescence computed tomography imaging

X-ray Fluorescence Computed Tomography (XFCT) is a widely-used experimental technique for investigating the spatial distribution of elements in a sample. However, image reconstruction for this technique is more difficult than for transmission tomography, one problem being self-absorption. In this work, we make use of known quantities and unknown density of elements of interest to express unknown attenuation maps. The attenuation maps are added to the contribution value of the pixel in the Maximum Likelihood Expectation Maximization (MLEM) reconstruction method. Results indicate that the relative error is less than 14.1%, which shows that this method can effectively correct L-shell XFCT.     

FSAE赛车电器设置与仪表研制

根据FSAE赛车规则的要求，提出FSAE赛车整车电气系统方案，说明了主要电器的设置，并针对原有发动机的ECU与改换后的进排气子系统无法匹配等问题，提出了解决办法，主要目的是提高赛车的加速性能；然后提出一种基于NEC公司的UPD78170883单片机的全数字式赛车仪表系统设计，阐述了车速表、转速表的电路设计、测量原理、误差分析、软件算法，最后通过实车验证了上述方案的可行性．