网络处理器中FBI单元的设计及其Verilog HDL实现

FBI(Fast Bus Interface)单元是实现网络处理器外部接口与网络处理器内部总线高速数据传输的关键。通过深入研究FBI单元,阐述了它的结构及其功能,运用Verilog HDL语言设计了一个FBI接口,在Model- sim SE PLUS 6．0上进行仿真,实现了整体模块的功能。     

α稳定分布下的加权平均最小p-范数算法

该文提出一种新的适用于α稳定分布噪声环境的自适应滤波算法,这种算法通过使加权平均误差函数的p-范数最小来实现自适应滤波.在这种算法的基础上,该文还得到两种新的动量LMP自适应算法.将这些新算法应用于估计AR模型的参数,计算机仿真的结果表明,该文提出的算法的性能比已有LMP算法的性能要更为优越.     

Analysis of Surface Plasmon Polariton Using Anisotropic Finite Elements

The anisotropic finite-element mesh is deployed in a vector finite-element method to numerically derive surface plasmon polaritons (SPPs) more efficiently. The superiority of the anisotropic mesh lies in the fact that SPP modes, predictably, have a sharp field variation in the surface-normal direction, whereas the variation along the surface-tangent direction is comparably gentle. A case study on metallic fiber shows that the employment of anisotropic finite elements reduces the problem size by a factor of seven.     

采用铟束流保护下的调制中断生长技术改善(0001)GaN表面形貌

使用分子束外延方法,采用In束流保护下的调制中断生长技术,在(0001)蓝宝石衬底上生长GaN薄膜.利用反射式高能电子衍射(RHEED)对生长进行实时监控,并用扫描电子显微镜(SEM)、原子力显微镜(AFM)和X射线衍射(XRD)法对GaN外延薄膜的表面形貌和晶体质量进行分析.实验结果表明:采用该技术生长的Ga极性GaN外延薄膜中的晶体表面残留Ga滴密度大大降低,GaN外延薄膜的表面形貌得到改善,其均方根粗糙度(RMS)由3nm降低为0.6nm,同时XRD双晶摇摆曲线测试的结果表明,GaN外延层的晶格质量也得到改善.     

Effect of CuO Addition on Microwave Dielectric Properties of 0.80Sm(Mg0.5Ti0.5)O3-0.20Ca0.8Sr0.2TiO3 Ceramics

The effects of CuO addition on phase composition, microstructure, sintering behavior, and microwave dielectric properties of 0.80Sm(Mg_0.5Ti_0.5)O₃-0.20 Ca_0.8Sr_0.2TiO₃(8SMT-2CST) ceramics prepared by a conventional solid-state ceramic route have been studied. CuO addition shows no obvious influence on the phase of the 8SMT-2CST ceramics and all the samples exhibit pure perovskite structure. Appropriate CuO addition can effectively promote sintering and grain growth, and consequently improve the dielectric properties of the ceramics. The sintering temperature of the ceramics decreases by 50°C by adding 1.00 wt.%CuO. Superior microwave dielectric properties with a ε _r of 29.8, Q × f of 85,500 GHz, and τ _f of 2.4 ppm/°C are obtained for 1.00 wt.%CuO doped 8SMT-2CST ceramics sintered at 1500°C, which shows dense and uniform microstructure as well as well-developed grain growth.     

面向无线网络容量和覆盖优化的分组调度算法

为了实现无线网络资源的高效利用,该文基于增强边缘用户调度公平性的目标提出一种通过参数来调节覆盖和容量目标的比例公平(-CCPF)分组调度算法,其可用于网络覆盖和容量优化(CCO)。该文首先证明该算法的收敛性,之后基于业务量分布、功率调整及该分组调度算法提出CCO机制,并在长期演进(LTE)网络下的一个试验的规则场景和一个基于实际网络数据的非规则场景中进行了仿真,验证了该机制能够在覆盖-容量优化机制下,实现更合理的资源利用率(RO),并同比例公平(-PF)算法相比在理论场景和实际场景下平均用户吞吐量分别提升了19%和33%。     

Transmission properties of the single mode fiber with a cross-sectional micro-channel investigated using time-domain finite difference (FDTD) method

Light scattering by a micro-channel intersecting core of a single mode fiber (SMF) has been investigated by use of two dimensional time-domain finite difference (2D-FDTD) method and the numerical results are in good agreement with those reported in the experiments. The transmission properties of the SMF with such a micro-channel can be attributed to the combined results of scattering effect and FP resonance effect. It is suggested that the SMF with micro-channel of about 4–6 μm in diameter can be effectively used for refractive index sensing with a high refractive index resolution up to ∼10⁻⁵.     

Constant Modulus Algorithm for Cochannel Signal Separation in Non-Gaussian Impulsive Noise Environments

The separation of cochannel signals is of interest in communication community. Some algorithms based on constant modulus (CM) have been previously developed to separate cochannel signals with the assumption of Gaussian channel noise. The mismatches of noise models between the assumed channel noise and the practical noise may occur. These mismatches will inevitably lead the performance of cochannel signals separation to degrade. In this paper the alpha-stable distribution is employed as noise model to simulate impulsive noise occurring in wireless channel. A constant modulus algorithm is proposed to separate the cochannel signals based on fractional lower-order statistics (FLOS). The convergence of the CM array is analyzed. Numerical simulations are presented to verify the accuracy of the analytical results.     

激光冲击强化声学诊断系统研究

为了开发一种有效的激光冲击强化工艺故障诊断系统,基于声学诊断原理,对激光冲击强化过程中采集到的声信号进行小波包分析,提取出能够指示故障状态的声学特征信息,并验证了其有效性。最后将提取的特征信息结合人工神经网络,建立了激光冲击强化的故障诊断系统模型。     

Atomic Ni Anchored Covalent Triazine Framework as High Efficient Electrocatalyst for Carbon Dioxide Conversion

Electrochemically driven carbon dioxide (CO₂) conversion is an emerging research field due to the global warming and energy crisis. Carbon monoxide (CO) is one key product during electroreduction of CO₂; however, this reduction process suffers from tardy kinetics due to low local concentration of CO₂ on a catalyst's surface and low density of active sites. Herein, presented is a combination of experimental and theoretical validation of a Ni porphyrin‐based covalent triazine framework (NiPor‐CTF) with atomically dispersed NiN₄ centers as an efficient electrocatalyst for CO₂ reduction reaction (CO₂RR). The high density and atomically distributed NiN₄ centers are confirmed by aberration‐corrected high‐angle annular dark field scanning transmission electron microscopy and extended X‐ray absorption fine structure. As a result, NiPor‐CTF exhibits high selectivity toward CO₂RR with a Faradaic efficiency of >90% over the range from ?0.6 to ?0.9 V for CO conversion and achieves a maximum Faradaic efficiency of 97% at ?0.9 V with a high current density of 52.9 mA cm^?2, as well as good long‐term stability. Further calculation by the density functional theory method reveals that the kinetic energy barriers decreasing for *CO₂ transition to *COOH on NiN₄ active sites boosts the performance.