湛江特呈岛红海兰混交群落种内种间竞争的研究

利用Hegyi提出的单木竞争指数模型分析湛江市特呈岛红海兰混交群落种内和种间竞争指数。结果表明,红海兰种内种间竞争指数随着林木径级增大而减少;径级在3.0-3.9cm时受到的竞争强度最大;种内竞争远大于种间竞争;种间竞争强度的顺序为海榄雌〉木榄〉秋茄树;红海兰种内、种间和林分竞争强度服从幂函数关系。

松栎混交林中马尾松的种内种间竞争

通过对马尾松(Pinus massoniana)-麻栎(Quercus acutissima)人工混交林的124株对象木及473株竞争木的调查,采用竞争影响区域法与HEGYI单木竞争模型相结合的方法对马尾松-麻栎人工混交林的种内、种间竞争关系进行研究。结果表明,样地内Ⅳ级和V级马尾松数量较多,所占的比重较大;I级马尾松幼苗数量较少。马尾松种内和种间竞争强度均随对象木径级的增大而减小,同一径级的种间竞争均大于种内竞争。竞争强度与对象木胸径的关系服从幂函数关系CI=AD^(-B),当对象木胸径DBH≥20cm时,竞争强度无明显变化。所得的预测模型能很好的预测马尾松-麻栎人工混交林种内和种间竞争强度。

A Novel Method for Preparing Approximately Micron-sized Polymethyl Methacrylate Microspheres with Clear Surface

Polymethyl methacrylate (PMMA) microspheres with clear surface and diameter close to 1 祄 were synthesized by newly soap-free emulsion polymerization. The results showed that the presence of ethanol and NaCl made the increase of diameter and distribution, while the presence of toluene could avoid the problem of the increase of distribution, resulting a harvest of PMMA microspheres with a diameter close to 1 祄.