Through observation and study,the optimum designing programs are showed as follows:the cross degree between shelter belt and do minant wind direction should be more than 45 degree,the main forest belt distance should be from 150 meter to 200 meter,the subbelt distance should be from 230 meter to 700 meter,the best belt structure is sparse and transparent structure.
通过观测和研究 ,得出风沙区农田防护林带的走向与主风方向的交角 ,不能小于 45° ,主林带间距 15 0m——— 2 0 0m ,副林带间距 2 3 0m——— 70 0m ,林带结构以疏透结构为最好 ,主林带一般由主林木 5— 6行组成 ,副林带由 2— 3行组成 ,再在迎风面和背风面配置 1行— 2行灌木和针叶
The coupling of bands in the continuous represntation of the interacting boson model is discussed, the method of calculation is given,and that the practical calculation can be realized in the continuous representation.
讨论了相互作用玻色子模型连续变量表示中的带间耦合，并给出了具体的计算方法，从而使连续变量应用于实际计算成为可能
The scheme of the research was conducted over the impact of different intervals between pasture belts on water and soil conservation as well as on physical and chemical characteristic of soil on the sloping arable land with the elevation of 150.
为探索云南数百万亩坡耕地的科学利用措施,在云南宣威15°坡耕地上设置试验小区,连续两年系统研究了9m、13m、17m三水平草带间距与水土保持和土壤理化性状的关系。