A new family of nonbinary sequences with three-level correlation property and large linear span

In this correspondence, we present a new family of nonbinary sequences with three-level nontrivial correlations and large linear complexity. The sequences may be considered as nonlinear analogues of the well-known sequences by Trachtenberg and Helleseth. It is shown that the family is optimal with respect to the Welch bound in terms of root mean square of all nontrivial correlations. We also determine the correlation distribution of the new family.     

Capacity evaluation of packet-switched CDMA system

In this letter, an extended definition for packet-switched CDMA system capacity based on the protocol stack characteristics is proposed. According to the extended definition, the capacity of the packet-switched CDMA system for different ARQ protocols and different channel models is investigated. The results show that, compared with the traditional definition, the extended definition is more appropriate for describing the packet-switched CDMA network capacity     

Microstructure and mechanical properties of a 2091 AlLi alloy—II. Mechanical properties: Yield stress and work hardening

Mechanical properties of a 2091 AlLiCuMg (Zr) alloy are investigated together with those of simpler AlLi (Zr) and AlCuMg (Zr) model alloys. The different contributions to the yield stress are estimated from the microstructure investigated in companion Paper I. Work hardening is described using Ashby's model, but taking into account the strain localization.     

多层蜂窝系统双向溢出呼叫模型及分析

该文给出了N层蜂窝覆盖系统双向呼叫溢出信道指配策略的一般模型及分析方法,并给出了一个4层模型分析结果。通过设定不同参数,该文方法可用于分析任意多层蜂窝系统双向溢出、单向上溢出、单向下溢出、部分双向溢出和部分单向溢出等呼叫溢出策略。     

基于神经网络的混沌信号源的设计及同步

该文应用具有全局最优的BP改进算法和神经网络的强大学习能力、逼近任意非线性能力和权值调整的灵活性来优化混沌信号源的设计,采用非线性负反馈实现了神经网络混沌信号源之间的同步。计算机仿真结果表明:由于该模型充分利用了逼近任意非线性能力和网络权值调整的灵活性,比单一混沌映射能产生更多的、具有良好相关性能的混沌信号,且易于同步。     

Optimisation of two-step sintering parameters to produce bioactive and dense zirconia-hydroxyapatite composite ceramics

3Y-TZP along with Hydroxyapatite (HAp) are common bioceramics used in bone tissue engineering scaffolds to yield better patient outcomes and faster healing times. However, significant differences in thermal expansion of these ceramics result in challenges to co-sintering these materials without losing functionality and strength. In this work, a two-step sintering (TSS) process was utilised to co-sinter composites using (1-x)3Y-TZP and xHAp where x varies between 20 and 80 wt%. A peak temperature of 1300 °C, a plateau temperature of 1175 °C, a holding time of 600 min and heating rate of 10 °C/min were the optimum TSS conditions for all compositions. The TSS process produced specimens with grain sizes between 0.5 and 1.2 µm and a compression strength between 88 and 176 MPa. The similarity in compression strength of these zirconia-hydroxyapatite composites with natural bone and the retention of HAp make them suitable for bone tissue engineering applications in load bearing areas.     

瞬时功率理论及其应用研究

讨论基于瞬时无功理论的各种谐波和无功检测方法在电网电压畸变情况下的适用性,独立设计有源电力滤波器对三相电力系统进行无功谐波综合补偿,并基于Matlab/Simulink仿真平台对系统进行建模仿真,仿真结果表明,所设计的并联型有源电力滤波器对系统的谐波无功综合补偿效果显著,验证了理论的正确性与可行性.