柞蚕林生态系统生物生产力与养分循环模式研究

本文研究了辽东山区不同经营强度下柞蚕林生态系统物质转运和养分循环。在同一个轮伐期内，柞蚕林叶生物量、年净生产量随剪伐年令的增加而增大，直到剪伐后5年呈下降趋势。植被总生物量介于22.23-24.56t·ha~(-1)。其中乔木层、灌木层、草本层各为17.84、2.82、3.17t·ha~(-1)。林地枯枝落叶层总量为3.56-4.37t·ha~(-1)。年净生产量介于8.51-8.92t·ha~(-1)·yr~(-1)。其中乔木层占53.7%、灌木层占16.3%、草本层占29.9%。当食叶强度为0、50%和75%时，年干物质归还总量分别为3.57-3.96、3.38-3.725和3.284-3.609t·ha~(-1)·yr~(-1)。干物质净输出各为0、93.34-117.59和140.02-176.36kg·ha~(-1)·yr~(-1)。干物质积累和分配的分隔模型阐明了系统中干物质现存量和流动量。柞蚕林植被养分积累总量为255.69-292.15kg·ha~(-1)。在乔木层中，叶 > 根桩、树干 > 侧根、多年生枝 > 当年枝、细根。柞叶在衰老过程中，养分浓度急剧下降（40.62-77.78%）。在不同食叶强度下，分别计算了营养元素的回运量、归还量、输出量和存留量、植被养分年吸收总量以及调整前后乔木层各器官的年净吸收量。养分循环的分隔模型阐明了不同经营条件下柞林-柞蚕系统养分的分配和流动特征。

Possible way to synthesize superheavy element Z=117

Within the framework of the dinuclear system model, the production of superheavy element Z = 117 in possible projectile-target combinations is analysed systematically. The calculated results show that the production cross sections are strongly dependent on the reaction systems. Optimal combinations, corresponding excitation energies and evaporation channels are proposed, such as the isotopes Bk-248,Bk-249 in Ca-48 induced reactions in 3n evaporation channels and the reactions Sc-45+Cm-246,Cm-248 in 3n and 4n channels, and the system V-51+Pu-244 in 3n channel.

Relativistic Mean Field Study of the Z=117 Isotopic Chain

The properties of the Z = 117 isotopic chain are studied within the framework of the axially deformed relativistic mean field theory (RMFT) in the blocked BCS approximation. The ground-state properties, such as binging energies, deformations as well as the possible.. decay energies and lifetimes are calculated with the parameter set of NL-Z2 and compared with results from the finite range droplet model. The analysis by RMFT shows that the isotopes in the range of mass number A = 291 similar to 300 exhibit higher stability, which suggests that they may be promising nuclei to be hopefully synthesized in the lab among the nuclei Z = 117.