松纵坑切梢小蠹虫害的仿真模型与生态防治的优化策略

根据松纵坑切梢小蠹的主要生物学特征,通过分析抚育间伐持续控制松纵坑切梢小蠹虫害的机理,应用复杂适应系统(CA S)理论,建立了模拟松纵坑切梢小蠹虫害的一种动态演化数学模型,并讨论了模型的收敛性.然后选用昆明小哨林场为背景,进行了各种抚育间伐决策的仿真,从中优选抚育间伐决策.结果表明:模拟优化方案与实际调查统计分析结果一致:均为弱度间伐与中弱度间伐控制蠹害效果最好.最后通过森林积材量与虫害程度之间的优化,给出了抚育间伐的优化策略.     

Existence and Concentration of Bound States of a Class of Nonlinear SchrSdinger Equations in R2 with Potential Tending to Zero at Infinity

In this paper, we establish the existence and concentration of solutions of a class of nonlinear Schr?dinger equation $$- \varepsilon ^2 \Delta u_\varepsilon + V\left( x \right)u_\varepsilon = K\left( x \right)\left| {u_\varepsilon } \right|^{p - 2} u_\varepsilon e^{\alpha _0 \left| {u_\varepsilon } \right|^\gamma } , u_\varepsilon > 0, u_\varepsilon \in H^1 \left( {\mathbb{R}^2 } \right),$$ where 2 < p < ∞, α ₀ > 0, 0 < γ < 2. When the potential function V (x) decays at infinity like (1 + |x|)^?α with 0 < α ≤ 2 and K(x) > 0 are permitted to be unbounded under some necessary restrictions, we will show that a positive H ¹(?²)-solution u _? exists if it is assumed that the corresponding ground energy function G(ξ) of nonlinear Schr?dinger equation $- \Delta u + V\left( \xi \right)u = K\left( \xi \right)\left| u \right|^{p - 2} ue^{\alpha _0 \left| u \right|^\gamma }$ has local minimum points. Furthermore, the concentration property of u _? is also established as ? tends to zero.     

不同炭化条件下炭化物的结构与性能表征

采用不同炭化工艺对杉木木屑进行热解,用拉曼光谱、X射线衍射技术对炭化物的微晶结构进行研究,揭示了其中的演变规律与形成特点。研究表明炭化条件对炭化物石墨化程度、微晶结构等影响较大,700 ℃是关键的炭化温度。从炭化物的石墨状微晶的形成与生长来看,二步炭化法比一步法好;不加盖炭化法比加盖法好;氛围气为空气的比氮气好;保温时间长的试样石墨化程度高。