POI共建LTE双路室分系统建设成本分析

详细论述了POI系统实现原理、POI系统技术特点、LTE室分双路常见解决方案;结合工程实际案例,着重论述了多家运营商是如何通过POI共建室分系统实现LTE室分双路建设方案的;详细分析了POI共建节约室分建设投资情况,为LTE双路室分系统共建方案的选取提供宝贵经验。     

服务网络中基于改进蚁群系统的服务路径选择

结合图理论及社交网络分析,将服务之间的互操作关系引入服务计算的过程中,构建一种基于服务关系的服务网络.提出服务网络的概念,分析服务之间的4种交互关系及特点,详细讨论服务网络中基于服务关系的服务组合优化问题.应用图模型将服务网络中服务路径选择问题转化为图论中多目标路径优化选择问题,通过具有良好交互的服务节点构建数学模型,以最少成本代价为目标,应用改进蚁群系统算法寻求最优路径.实验结果证明了算法的可行性及有效性.     

An amphoteric poly(VAc‐DBM‐AM‐DMAPS) emulsion focusing on the ecological sand‐fixing in salty desert: Structure and properties

In order to control the impacts of blown sand in salty desert, in this article, the amphoteric emulsion, for the first time, was applied as an ecological sand‐fixing material. This study started from the synthesis of the poly{vinyl acetate‐dibutyl maleate‐acrylamide‐co‐3‐[N‐(2‐methacroyloylethyl)‐N, N‐dimethylammonio]‐propane sulfonate} [P(VAc‐DBM‐AM‐DMAPS)] copolymer emulsion. Then, the structures, composition, thermal property of the emulsion were characterized by ¹H‐NMR, FTIR, and DSC, respectively. The basic properties of the emulsion and salt tolerance of the latex films were measured by using viscometer, dynamic light scattering, and laser Doppler electrophoresis also. And the sand‐fixing properties of the emulsion were evaluated. Finally, the influence of the emulsion on the growth of soil microbe and plants were discussed for understanding its ecological effect. The experimental results showed that the emulsion has been successfully synthesized and could be as an ecological sand‐fixing material. The related reason is that, first, the emulsion could significantly improve the compressive strength and water retaining; second, the emulsion had good thermal aging, freeze‐thaw stabilities and salt tolerance to withstand the changes in temperature and NaCl concentration of salty desert; third, the influence of the emulsion on the growth of plants and microbe of sand also showed a dependable ecological effect. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43715.     

热处理对双辊铸轧ZK60镁合金组织及阻尼性能的影响

采用双辊铸轧法制备了ZK60镁合金条带,采用金相显微镜(OM)和动态机械分析仪(DMA)研究了热处理后ZK60镁合金条带的组织和阻尼性能。退火处理后,组织较为均匀。T6处理后组织转变为均匀的等轴晶。在温度-阻尼谱中出现了2个温度阻尼峰,P1峰为弛豫型阻尼峰,其激活能为132 kJ/mol,P2峰为非弛豫型再结晶阻尼峰。T6处理条件下,时效时间为6 h时,呈现典型的位错型应变-阻尼图谱;在其他时效时间下,呈现2种混合位错型的应变-阻尼图谱。T6态双辊铸轧ZK60镁合金的应变-阻尼性能遵循G-L理论。     

Design and simulation of thermal residual stresses of coatings on WC-Co cemented carbide cutting tool substrate

Large thermal residual stresses in coatings during the coating deposition process may easily lead to coating delamination of coated carbide tools in machining. In order to reduce the possibility of coating delamination during the tool failure process, a theoretical method was proposed and a numerical method was constructed for the coating design of WC-Co cemented carbide cutting tools. The thermal residual stresses of multi-layered coatings were analytically modeled based on equivalent parameters of coating properties, and the stress distribution of coatings are simulated by Finite element method (FEM). The theoretically calculated results and the FEM simulated results were verified and in good agreement with the experimental test results. The effects of coating thickness, tool substrate, coating type and interlayer were investigated by the proposed geometric and FEM model. Based on the evaluations of matchability of tool substrate and tool coatings, the basic principles of tool coating design were proposed. This provides theoretical basis for the selection and design of coatings of cutting tools in high-speed machining.

     

7050高强铝合金铆钉丝材T73双级时效工艺

针对国产7050高强铝合金铆钉丝材,采用室温拉伸、室温剪切、镦粗试验的方法,研究了经177～182℃不同二级时效时间后7050铝合金丝材的性能。利用扫描电镜(SEM)、透射电镜(TEM)观察合金不同时效工艺下断口组织和析出相形貌特征。结果表明,拉伸强度和剪切强度随二级时效温度的升高、二级时效时间的延长逐渐降低,剪切强度低于330 MPa时镦粗试样不开裂。TEM微观组织显示,随二级时效温度的升高、时间的延长析出相形貌变化不大,但析出相的尺寸随时效温度的升高逐渐长大、间距逐渐增大;拉伸断口形貌显示,二级时效的断裂方式均为韧窝断裂和沿晶断裂的混合断裂模式,随二级时效温度的升高和保温时间的延长,断口中韧窝数量逐渐增加且尺寸变大,沿晶断裂逐渐减少。     

基于FWD的半刚性基层开裂状况无损评价模型

为无损判别半刚性基层开裂状况,以落锤式弯沉仪(FWD)为平台反演基层模量,分析弯沉盆匹配法和规律法模量反演结果的差异,进行基层反演模量与开裂状况的相关性分析,以基层模量比为评价指标,建立基层开裂状况无损评价模型和评价标准。研究表明：铣刨后的半刚性基层表面可视化损坏模式主要为裂缝;与弯沉盆匹配法相比,弯沉盆规律法的模量反演结果唯一且土基模量变异性较低;基层模量比与基层开裂状况在半对数坐标下具有良好的线性关系;基层开裂状况可分为四类,基层模量比分界值分别为0.68、0.47、0.30。该评价模型适用于不同强度的半刚性基层损坏状况的无损判别,可为路面大中修设计是否翻修半刚性基层提供决策支持。     

水力旋流器内空气柱直径的研究

探讨了不同排料方式下的水力旋流器的溢流口直径和压力降对空气柱直径的影响，分析了水封式水力旋流器底流背压、溢流背压及系统压力对空气柱直径的影响规律。可作为水力旋流器内空气柱的操作控制及改善水力旋流器工作性能的依据。