Verification Theory and Approximate Optimal Harvesting Strategy for a Stochastic Competitive Ecosystem Subject to Lévy Noise

This work focuses on optimal harvesting problems for a stochastic competitive ecosystem subject to Lévy noise. A verification theorem for corresponding harvesting strategy is established, which offers sufficient conditions for deriving an optimal harvesting strategy and an upper bound of the value function. For a given instantaneous marginal yields function, a concrete upper bound of value function is constructed by applying the verification theorem obtained in this paper. Meanwhile, the monotonicity of value function is investigated. Also, an ε-optimal harvesting strategy is designed to find an approximate optimal harvesting strategy for those harvesting problems with no exact optimal harvesting strategy. Finally, by choosing appropriately Markov decision process defined on a discrete state space, a computational method for an optimal harvesting strategy is designed and a concrete example is also given to show the implementation of the algorithm.     

生气量计算方法研究

本文利用热模拟法获得各类未成熟生油岩不同热演化阶段的产烃率,用地温梯度法获得成熟生油岩各演化阶段的体积,将二者结合,根据干酪根热降解成烃机理及物料平衡原则,提出了生气量计算公式。通过模拟温度与镜质体反射率的转换,使人工模拟与地质条件下的自然热演化相联系,按照公式求出各热演化阶段的生气量,各阶段之和即为该盆地的总生气量。     

基于CF_4/Ar高密度感应耦合等离子体的BZN薄膜的刻蚀工艺研究

使用CF4/Ar高密度感应耦合等离子体(ICP)对磁控溅射法制得的铌酸锌铋(BZN)薄膜进行了干法刻蚀工艺研究。分析了BZN薄膜的刻蚀速率随工艺气体流量比、总流量和工作压强的改变而出现极大值的原因,展示了BZN薄膜的刻蚀速率随ICP功率的增大而线性增加的趋势。研究结果表明,使用CF4/Ar感应耦合等离子体对BZN薄膜进行刻蚀的机理为物理辅助的化学反应刻蚀。BZN薄膜的最佳刻蚀工艺参数为CF4/Ar流量比3/2、总流量25sccm、工作压强1.33Pa、ICP功率800W,使用此参数对BZN薄膜进行刻蚀,最大刻蚀速率为26nm/min,刻蚀后薄膜边缘齐整、表面光滑、形状完整。     

Characterization of ThMn_(12)-structure Stability

A series of YTi(Fe_(1-x)_(11)alloy withx=0.00,0.01,0.03,0.04,0.05,0.07 and 0.10 hasbeen investigated by measurement of the structuralproperties and ~(57)Fe Mssbauer experiments.Thepure ThMn_(12)-structure phase exists at x≤0.03 andis absent at x>0.03.The reasons for lower satura-tion magnetization and lower energy product of theThMn_(12)-structure compounds were given.Thecrystal structure relations     

电台电力系统特殊电压值的矢量分析与理论计算

本文应用电压矢量分析法对电台电力系统中不同点位之间的电位差进行分析，从中导出两组计算特殊电压值的理论公式，为电台电力系统的维护提供了一个分析和解决实际问题的思路和方法。     

基于小世界理论的自组织计算网络有效调度算法

以小世界（Small-world）模型作为理论依据，阐述了基于P2P的自组织计算网络的构造和基于该网络的计算任务调度算法，对计算网络的若干特性（诸如高聚合性和低搜索路径）以及调度的效能进行了分析。该文构造的计算网络表现出明显的自组织特性，具有较好的可扩展性和自组织能力，能为计算资源的调度提供很好的支持。     

纳米微晶软磁合金中的磁织构

用Ｍｏｓｓｂａｒｕｅｒ谱方法研究了超微晶软磁合金中存在的磁织构现象，对测与未测过磁性的两组不同温度下退火的Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９合金的测量结果表明，晶化以后在非晶条带平面内出现了明显的沿带和择优取向的宽畸成分。     

MOSSBAUER STUDY ON MAGNETIC ANISOTROPY OF AMORPHOUS ALLOY Fe_(71)Ni_(10)B_(13)Si_4C_2

Magnetic anisotropies of the amorphous alloy Fe_(71)Ni_(10)B_(13)Si_(14)C_2 annealed in magnetic fieldhave been studied using Mossbauer spectroscopy and X-ray diffraction.It is shown that thedistribution of moments in the annealed sample are determined by both stress-produced andthermomagnetic treatment-induced magnetic anisotropies.     

基于非晶态铌酸锌铋薄膜的新型反熔丝器件

本文提出了一种基于非晶态铌酸锌铋（a-BZN）介质材料的新型反熔丝器件并对其性能特征进行了研究。考察了a-BZN反熔丝器件的关态特性,选用从上至下的编程方向对反熔丝器件进行击穿,其击穿电压约为6.56V。获得了a-BZN反熔丝器件的关态电阻,约为1GΩ。表征分析了击穿后的a-BZN反熔丝器件的表面形貌。研究了a-BZN反熔丝器件的编程特性以及编程后的开态特性,结果表明a-BZN反熔丝器件所需编程时间约为0.46ms,编程后其开态电阻约为26.1Ω。对比分析了a-BZN反熔丝器件与结晶态铌酸锌铋（cp-BZN）反熔丝器件和栅氧反熔丝器件在性能特征等方面的差异。     

MSSBAUER INVESTIGATION ON QUENCHED STRUCTURES OF 40CrNiMo STEEL

The martensite microstructure,amount of retained austenite and its carbon concentration inthe 40CrNiMo steel quenched at various conditions have been investigated by using trans-mission Mossbauer spectroscopy at room temperature.It was shown that high-temperaturequenching and thermomechanical quenching has little influence on amount of retainedaustenite,thus the toughening effect of quenching was attributed to bulk lath martensite andits refining.