黏合剂对其ZSM-5分子筛成型物裂解石脑油的影响

为考察成型时,黏合剂性能对ZSM-5分子筛的影响,对同一分子筛用六种不同黏合剂捏合,挤条成型,进行SEM、NH₃-TPD和N₂物理吸附表征。结果表明,六个成型物在形貌和BET比表面积均无明显差异,二次孔数量明显比分子筛原粉增加。所用纯硅溶胶黏合剂的成型物,其NH₃-TPD酸量、微孔体积和微孔比表面积低于其分子筛原粉。所用含铝黏合剂的成型物,其NH₃-TPD酸量、微孔体积和微孔比表面积变化不明显,BJH累积孔体积明显增加。在固定床反应器中于600 ℃裂解石脑油。发现,纯硅溶胶黏合剂成型物的乙烯+丙烯收率明显低于含铝黏合剂。     

衰落信道下基于中继选择与功率控制的节能协作通信

In order to save energy and make more efficient use of wireless channel, this article puts forward an energy saving cooperative relaying scheme which actuates the cooperative transmission only when the feedback from the destination indicates failure of the direct transmission. The proposed scheme selects the optimal relay and its corresponding transmission power in each time slot based on channel condition and residual energy with the objective of minimizing energy consumption and extending network lifetime. In the study, the finitestate Markov channel model is used to characterize the correlation structure of channel fading in wireless networks, and the procedure of relay selection and transmission power decision is formulated as a Markov decision process. Numerical and simulation results show that the proposed scheme consumes less energy and prolongs the network lifetime.     

集成共享平台方案的研究

提出一种集成共享平台,是一种可对外提供多种基本且可扩展接口,以适应不同接口的应用系统。基于此平台,多个系统之间可以相互调用多种服务,提高服务管理功能的同时进行无障碍的信息交互;及时发现分析系统交互异常信息,实现智能维护管理。当出现新的接口协议时,只需针对所述平台进行一次新接口协议适配器的开发,即可完成新接口的接入,提高了平台开发效率,降低了开发维护成本。本平台将传统的点对点的应用方式改为多对多的总线方式,实现了各系统间简单便捷的信息交互,优化了各系统间的架构,易于管理和维护,减少了接入系统的接口改造工作。     

移动流媒体端到端质量管理研究

本文在介绍移动流媒体网络结构与业务特征的基础上,提出了多角色参与情况下流媒体业务的端到端质量管理方法,特别对移动流媒体端到端层次质量管理体系和流媒体质量评估指标进行了探讨和建议,文中还针对指标量度性的两个重要解决手段--关联分析方法和测量技术进行了总结.     

基于集中监控数据资源的4G基站退服故障预警模型

4G无线基站设备是直接影响信息通信网络用户服务质量的重要环节,而4G无线基站退服故障将直接阻断用户正常通信.针对上述问题,基于集中监控告警消息数据资源通过关联规则挖掘和时间追溯推演分析,实现了4G基站退服故障的短期预警.基于集中监控设备性能数据资源通过网元分类(数据清洗、特征筛选、网元聚类)、指标降维(按簇分组、主成分分析)、主成分表达式与退服故障关联分析、性能指标选取及阈值分析实现了4G基站退服故障长期预警,经测试可准确预测次月27.8％的4G基站设备退服故障.     

虚拟两天线蜂窝网络中考虑中继公平性的协作博弈调度方法(英文)

In thsssse cellular network, Relay Stations (RSs) help to improve the system performance; however, little work has been done considering the fairness of RSs. In this paper, we study the cooperative game approaches for scheduling in the wireless relay networks with two-virtual-antenna array mode. After defining the metric of relay channel capacity, we form a cooperative game for scheduling and present the interpretation of three different utilization objectives physically and mathematically. Then, a Nash Bargaining Solution (NBS) is utilized for resource allocation considering the traffic load fairness for relays. After proving the existence and uniqueness of NBS in Cooperative Game (CG-NBS), we are able to resolve the resource allocation problem in the cellular relay network by the relay selection and subcarrier assignment policy and the power allocation algorithm for both RSs and UEs. Simulation results reveal that the proposed CG-NBS scheme achieves better tradeoff between relay fairness and system throughput than the conventional Maximal Rate Optimization and Maximal Minimal Fairness methods.     

ZSM-5分子筛催化剂稳定性的研究

为观察C₄烯烃转化制丙烯过程中影响催化剂稳定性的因素，对经历不同反应时间（即新鲜、反应48h、反应650h、反应650h后再生和再生后再进行反应48h）的系列ZSM-5分子筛催化剂进行了表征。结果表明，经历长期反应后，催化剂微孔体积和BJH吸附累积孔体积明显降低；再生后，孔体积可以恢复到新鲜催化剂的初始值。与此同时，NH₃-TPD酸量不仅降低，而且再生后也不能得到恢复。与高温水蒸气处理的催化剂相比较，²7Al MAS NMR表征结果说明，积炭因素对催化剂孔体积的影响可通过再生消除，而分子筛骨架铝丢失和分子筛晶胞参数的降低对催化剂酸量的持续减少起主要作用。长期在高温水蒸气条件下运行后，催化剂酸量可维持在一定水平，使催化剂长期稳定运行成为可能。     

一种能量高效的基于主成分分析的多接入网络选择策略

This paper brings forward a novel dynamic multiple access network selection scheme (ND MAS), which could achieve less energy loss and improve the poor adaptive capability caused by the variable network parameters. Firstly, a multiple access network selection mathematical model based on information theory is presented. From the perspective of information theory, access selection is essentially a process to reduce the information entropy in the system. It can be found that the lower the information entropy is, the better the system performance fulfills. Therefore, this model is designed to reduce the information entropy by removing redundant parameters, and to avoid the computational cost as well. Secondly, for model implementation, the Principal Component Analysis (PCA) is employed to process the observation data to find out the related factors which affect the users most. As a result, the information entropy is decreased Theoretical analysis proves that system loss and computational complexity have been decreased by using the proposed approach, while the network QoS and accuracy are guaranteed. Finally, simulation results show that our scheme achieves much better system performance in terms of packet delay, throughput and call blocking probability than other currently existing ones.     

Bi2MoO6纳米薄膜的制备及其光电性能

采用非晶态配合物法在ITO导电玻璃上制备了Bi2MoO6薄膜. 采用扫描电子显微镜(SEM)、X射线衍射(XRD)、激光拉曼光谱(LRS)、紫外-可见漫反射谱(DRS)、光电流响应谱、光电转换量子效率(IPCE)等技术研究了Bi2MoO6薄膜的制备工艺、形貌、结构与薄膜光电性能的关系. 结果表明, 500 ℃、1 h焙烧后的Bi2MoO6薄膜为γ-Bi2MoO6晶相, 沿(131)晶面方向生长, 薄膜厚度约为69 nm. 随着焙烧温度的升高和焙烧时间的延长, Bi2MoO6薄膜的平均颗粒度增大, 并且在525 ℃焙烧出现β-Bi2MoO6和γ’-Bi2MoO6晶相. Bi2MoO6薄膜具有可见光响应活性, 在可见光照射下可以产生光电流, 优化条件下的Bi2MoO6薄膜在400 nm的光电转换量子效率可以达到2.14%. 薄膜的光电响应和光电转换量子效率受薄膜形貌及结晶状态影响, 可以通过控制薄膜的制备条件来提高薄膜的光电转换量子效率.