AOS SLS空间链路建立协议的仿真设计

针对AOS SLS空-地通信系统,提出了一种空间链路建立协议,设计提供了协议的关键参数,如空-地数据传输协议的数据单元、链路建立成功概率及同步时隙分配等,最后给出详细的链路建立工作流程,并对协议进行仿真,结果表明该协议能够快速有效地建立链路.     

AOS系统中的帧同步技术性能分析与仿真

为提高高级在轨系统（AOS）中数据传输的可靠性,对AOS帧同步技术进行研究。在分析了帧同步状态转移过程中可能出现的漏检现象与虚警现象的基础上,采用经典Z变换方法,研究了选取不同长度的附加帧同步标记、前方保护时间和后方保护时间对帧同步入锁时间、误锁概率、误锁后最快解锁概率和帧同步保持时间等重要性能参数的影响,并给出了仿真结果。最后给出了不同误码率下AOS帧同步参数选取的建议值,为实际应用提供参考.     

一种基于AOS格式的多相水平集快速分割方法

采用迎风格式的水平集算法实现需要在曲线演化过程中重新初始化水平集函数的要求,为保证算法的稳定,时间步长选取较小值,算法运行速度较慢。文中基于无须重新初始化的水平集方法,在算法数值实现中引入AOS半隐格式,对基于不同统计模型的水平集分割算法给出统一的数值实现。以二相水平集分割算法为基础提出一种新的多相水平集分割方法。该方法采用一个水平集函数进行多次演化实现多区域分割,其优点包括：1)采用AOS半隐格式,该格式无条件稳定,可采用较大的时间步长;2)对多个统计模型进行统一处理;3)采用单一的水平集函数进行演化,减少水平集演化方程的数量,算法更加灵活。实验结果表明,该方法具有较快的分割速度,对具有多个区域的图像能够进行较准确的分割。     

基于高级在轨系统的可重构复接器的设计

随着空间科学技术的快速发展,航天器的数据传输系统的任务变得日益复杂。传统复接器所支持的业务类型比较单一,其复用方式和调度策略往往都是固定不可变的。本文采用CCSDS建议的高级在轨系统(AOS)体制,设计一个可重构复接器,支持多种业务类型,兼容多种复用方式。通过配置寄存器的方式重构其复用方式和调度策略,具有极大的灵活性。     

一种改进的一致性扩散图像增强方法

一致性扩散是分析图像中定向结构的重要的预处理步骤,现有的一致性扩散图像增强方法难以识别图像中的弱边界。本文提出了一种改进的扩散方法,该方法构建了一种结合二阶方向导数信息的结构张量,能够精确分析图像中的复杂弱边界,同时与经典结构张量互为补充以检测图像的强边界。在此基础上设计了新的扩散张量,并采用了基于(加性分裂算子AOS)策略的数值计算方法。通过对比实验证明,该文算法的效果良好并具有很高的效率, 实现了在去除噪声的同时精确保护图像中的强弱边界。     

Fenton degradation of 4-chlorophenol contaminated water promoted by solar irradiation

The degradation of 4-chlorophenol (4-CP) contaminated water by Fenton process with or without solar irradiation assistance were investigated. It was found that the COD degradation and mineralization efficiency of 4-CP were more than 90% when a 30 min treatment of solar photo-Fenton oxidation process was applied and under an optimum [H₂O₂]₀/[Fe²⁺]₀ ratio of 40, the COD degradation and mineralization efficiency increased 65% as compared to Fenton oxidation. Meanwhile, the AOS values increased from −0.33 to 2.13 in solar photo-Fenton process while no significant improvement for AOS values was found in Fenton process, implying a higher degree of oxidation for 4-CP in solar photo-Fenton process. In addition, increasing the intensity of solar irradiation seemed to be beneficial for treatment of 4-CP contaminated water. Formation of chloride ion as a result of mineralization of organically bounded chlorine was identified during the treatment of 4-CP solution. Near-stoichiometric accumulation of chlorine was observed during the degradation of 4-CP in both Fenton and solar photo-Fenton processes. However, accumulation rate of chloride ions were much faster in solar photo-Fenton process. The degradation of 4-CP was found to obey a pseudo-first-order reaction kinetics. As compared to Fenton process, the presence of solar light in photo-Fenton process increases the reaction rate by a factor of 6.5 and 15.8 for COD and TOC degradation, respectively. In other words, during the treatment of 4-CP contaminated water, solar photo-Fenton process possesses notably higher mineralization efficiency in a relatively short radiation time as compared to Fenton process, and could enhance the degradation treatment of refractory organic wastewater such as 4-CP in a cost-effective approach.     

“傲视”——基于P2P技术的实时流媒体系统

在本篇论文中介绍了一个开发成功的，基于P2P技术的实时流媒体系统——“傲视”。该系统在数据传输方式上利用了P2P的原理．即每一个用户在接收服务器数据的同时，相互之间进行一定数据交换，这一原理类似于著名的软件BitTorrent（BT）。由于在数据传榆过程中。用户之间可以相互交换数据，而并不需要一定从服务器获取数据，因此使得该系统具有两个明显的技术优势：1．降低媒体源的硬件要求。2．降低信号源的输出带宽要求。经过校内测试，利用该系统只需要普通的个人电脑（P4 1．6G，256M内存）利用学生宿舍的100M带宽的网口．就可以在校园网中对全校上百用户进行多媒体网络广播（548Kbps）。实现学生个人电台、个人电视台功能。     

基于AOS的线性种子扩散图像分割方法研究

研究了修改Perona-Malik模型的线性种子扩散的图像分割方法。针对显式差分格式只能采用小步长的问题，改为隐式差分格式，并采用加性算子分裂（AOS）算法求解。二维图像测试表明，基于AOS的算法在稳定性和计算复杂度等方面都取得了较好的结果。     

AOS的生产工艺、性质及应用

本文叙述了A0S(α-烯基磺酸盐)的生产工艺、性质及其在化妆品和洗涤用品中的应用并提供了一些参考配方。     

NMR study on sulfonation of internal olefins

Terminal olefins can be converted into the corresponding sulfonates by sulfonation with SO₃ followed by hydrolysis, the products are used as detergent ingredients. Although internal olefins were also expected to be good feed stocks, it was difficult to convert them into the corresponding sulfonates with as good of a yield as that of terminal olefins under the same synthesis conditions. Our studies have been carried out in order to clarify the reason for poorer conversion of the internal olefins. It was found by a nuclear magnetic resonance spectroscopic study that the major components of the sulfonated intermediate of internal olefins wereβ-sultones, the amounts of which were usually very small in sulfonated terminal olefins. A portion of theseβ-sultones was desulfonated, depending on temperature, to the original olefins and the corresponding sulfate salts during alkaline hydrolysis. The prevention of desulfonation of theβ-sultones in the hydrolysis process was one of the most important aspects for the production of internal olefin sulfonates. Finally, by keeping the hydrolysis temperature below 35°C, the conversion of internal olefins into sulfonates was achieved with the same yield as that of conventional terminal olefins.