<正>对篌竹生长规律进行了研究。结果表明，篌竹出笋时间约始于4月8日，历时约32d，出笋初期出笋少，盛期、末期出笋数较多，但末期持续时间较长，退笋率随着笋期的推移先不断增加后下降。砍伐样方的成竹率比未砍伐样方的高。较早同生群幼竹高生长遵循逻辑斯蒂曲线方程，而较晚同生群幼竹高生长符合指数函数曲线方程，较早同生群的高度高于较晚同生群。

The combustion chamber and tailpipe is a main part of Helmholtz type pulse-jet engine. How both the acoustics condition formed by structure parameters of five kinds combustion chamber and tailpipes and calefaction condition constituted by three kinds fuel restrictor opening affect the work frequency of pulse engines had been studied. The conclusion is that the calefaction condition intensively works on the work frequency of a pulse-jet engine in the change range of the diameter of the cylindric part of the combustion chamber in the paper,on which the acoustics condition has a little effect.