field to field survey

Has analyzed the Helmholtz coil center region axial magnetic field distribution, gave one kind to survey the Helmholtz coil magnetic field distributed one new method.

分析了亥姆霍兹线圈中心区域轴向磁场的分布，给出了一种测量亥姆霍兹线圈磁场分布的一种新方法。

Methods Using documents review, interview and questionnaire survey, field observation and field visit to collect data and evaluate the effect.

方法采用定量研究与定性研究相结合的方法进行评估，包括文献阅读、访谈、问卷调查、现场观察与考察。

In rice field, chironomid midges are very abundant. Currently, our knowledge about chironomid midges in rice field is limited to the species survey as a neutral group.

目前我国关于稻田摇蚊的研究局限于种类描述和将摇蚊作为一类中性昆虫的调查。