基于部分可观察马尔可夫决策过程的受控无线网络系统动态资源分配

研究了受控无线网络的动态资源分配。针对传统无线通信传输模型的局限性随着无线通信系统架构的发展日益凸显的问题,提出了一种引入反馈控制策略的受控无线网络模型。该模型结合部分可观察马尔可夫决策过程(POMDP),将用户接收功率与数据传输误码率作为反馈观测对象,对通信小区内基站天线开启数与用户接入数进行动态资源最优匹配。仿真结果表明,这种方法能够有效提升系统传输能效性与可靠性,降低传输误码率,改善系统资源动态匹配控制性能。     

Influence of crack closure on the stress intensity factor in bending plates — A classical plate solution

Based on the classical plate theory in conjunction with the assumption of line contact at the compressive edge of a crack face, closed form solutions were presented for a through-the-thickness central crack in an infinite plate subjected to all around bending. The complete solutions were obtained by superposing the membrane components due to the contact forces at the crack face to the non-closure bending components. The distribution of the contact forces was found uniform by considering the contact condition which prevents mutual penetration of the crack faces at the compressive edges. The results showed that the closure of the crack faces tends to reduce the crack opening displacement at the tension side and, consequently, reduce the stress intensity factor. The finite element method was also used to investigate the present problem. The modified crack closure method in combination with the finite element method was used to find the stress intensity factors. Close agreement between the finite element and the analytical solutions was observed.     

空调与海水淡化联合运行方案研究

简单介绍了船用海水淡化装置的种类和应用,并提出了一种新的远洋船舶中海水淡化系统与中央空调系统联合运行的思路,并对此方案的可行性与前景进行了研究与分析。     

Fabrication and properties of sulfur (S)-doped ZnO nanorods

Highly-aligned sulfur (S)-doped ZnO nanorods have been grown using the hydrothermal approach at 90 °C for 2 h onto quartz substrate pre-coated with ZnO seed layer deposited by radio frequency magnetron sputtering system. The morphology, crystal structure, and transmittance of the S-doped ZnO nanorods grown with varied sulfur concentration have been investigated. The scanning electron microscope images showed that the S-doped ZnO nanorods dimension is affected by sulfur doping. The nanorods doped with sulfur concentration of ~1, 1.5, and 2 at.% found to show nanorods with an average diameter of ~130, 170, and 270 nm respectively. X-ray diffraction measurements revealed that the sulfur-doped ZnO nanorods have hexagonal-wurtzite crystal structure and grown vertically in the (002) plane along c-axis perpendicular to the substrate. The nanorods doped with 1 at.% sulfur showed ~70 % transmittance in the visible region while the nanorods doped with 2 at.% sulfur showed transmittance of ~77 % and exhibited blue shift in the fundamental absorption edge.     

高层建筑和风作用的耦合响应分析

本文研究了高层建筑结构和风作用的耦合振动响应,得到一个具有气体粘性的惯性力项和高阶的风速波动项的非线性微分方程组,应用简易的Park差分法求解,分析了影响结构风振响应的主要因素。获得了具有较好参考价值的风振响应分析资料。     

蒸发冷却空调冷水集成系统

介绍风侧蒸发冷却空调技术与水侧蒸发冷却空调技术的异同之处,以蒸发冷却空调冷水集成系统的形式介绍水侧蒸发冷却空调设备类型,并对其在实际工程中的应用进行分析,以期为业内人士对水侧蒸发冷却空调技术的认识提供一些参考。