基于Simulink的数据链系统仿真及性能分析

阐述扩频通信的基本原理及其在数据链系统中的应用,使用Matlab／Simulink软件构建了猝发数据链系统的仿真系统模型,通过分析仿真结果,得到不同输入信号强度下信噪比与捕获概率的关系,验证了算法的正确性_同时通过时系统指标分配浅析,提出工程应用时中频接收机的动态范围扩展可以为接收系统带来性价比的提升。     

Optimization of Al_2O_3/SiN_x stacked antireflection structures for N-type surface-passivated crystalline silicon solar cells

In the case of N-type solar cells,the anti-reflection property,as one of the important factors to further improve the energy-conversion efficiency,has been optimized using a stacked Al₂O₃/SiN_x layer.The effect of SiN_x layer thickness on the surface reflection property was systematically studied in terms of both experimental and theoretical measurement.In the stacked Al₂O₃/SiN_x layers,results demonstrated that the surface reflection property can be effectively optimized by adding a SiN_x layer,leading to the improvement in the final photovoltaic characteristic of the N-type solar cells.     

进阶持续性渗透攻击的特征分析研究

进阶持续性渗透攻击是一类针对特定组织或者目标的一系列攻击行为的总称。这种攻击具有渗透行动上的复杂性和攻击手段上的多元性。通过对于进阶持续性渗透攻击的流程分析发现:进阶持续性渗透攻击在发展过程中具有长期性和阶段性,其中攻击行为在静态和变化态中交替转换;另一方面,进阶持续性渗透的一系列攻击在使用攻击方法上同时使用现有的多种手段,具有非单一性和间接性,使得受害方难以发现并且单一防范工作难以奏效。     

周期注入LD开环同步的理论研究

以单周期注入为例,数值模拟并讨论了注入频率和注入光场波动强度对LD同步特性的影响.从功率和相位角度讨论了LD注入锁定的实现,并使用相似指数作为参考标准来评价同步性能.结果表明:注入光场的频率和振幅波动对系统的动态特性和同步性能有显著影响.当注入强度足够大时,系统实现注入锁定;增大调制指数,将抑制同步区域.因此,可以通过增加注入强度或减少注入振幅波动来实现精确同步.研究特定注入强度下主LD调制指数和调制频率相空间的同步品质发现,相似指数的最小值出现在调制频率1～10 GHz间,且随调制指数的增加向低频方向移动.     

双模压缩真空态在Tavis-Cummings模型中量子态保真度

考虑了原子的偶极相互作用,通过计算Tavis-Cummings模型下压缩真空态的保真度,阐明了在双模压缩真空态与环境(原子)通过双光子发生相互作用过程中量子信息的保真程度随时间的演化关。通过计算机模拟出两原子处于各种初态下时原子、光场和系统的保真度随时间的演化图象,分析出三者在压缩指数r、偶极相互作用常数ga和相位(?)等改变时的变化情况,结果表明r和k值的改变对于提高保真度具有重要意义。当两原子处于基态时减小r和当两原子处于一Bell基时增大都可以显著的提高体系的保真度。     

Low-complexity iterative equalization for EDGE with bidirectional processing

We present a new and simple iterative equalization scheme for the enhanced data rates for global evolution (EDGE) wireless system. This scheme can significantly reduce the number of trellis states in a maximum a posteriori probability (MAP) equalizer via delayed decision-feedback (DDF) approach. Relying on the mechanism of decision feedback in the DDF trellis, bidirectional processing can be applied to exploit the time diversity of the received signal bursts for a more reliable equalizer output. With mild increase in computational complexity over the more traditional single-directional (Si) DDF turbo equalizer, the bidirectional turbo equalizer can achieve a significant performance gain.     

A new adaptive two-stage maximum-likelihood decoding algorithm for linear block codes

In this paper, we propose a new two-stage (TS) structure for computationally efficient maximum-likelihood decoding (MLD) of linear block codes. With this structure, near optimal MLD performance can be achieved at low complexity through TS processing. The first stage of processing estimates a minimum sufficient set (MSS) of candidate codewords that contains the optimal codeword, while the second stage performs optimal or suboptimal decoding search within the estimated MSS of small size. Based on the new structure, we propose a decoding algorithm that systematically trades off between the decoding complexity and the bounded block error rate performance. A low-complexity complementary decoding algorithm is developed to estimate the MSS, followed by an ordered algebraic decoding (OAD) algorithm to achieve flexible system design. Since the size of the MSS changes with the signal-to-noise ratio, the overall decoding complexity adaptively scales with the quality of the communication link. Theoretical analysis is provided to evaluate the potential complexity reduction enabled by the proposed decoding structure.     

栀子总环烯醚萜苷纯化工艺研究

目的：优选栀子总环烯醚萜苷的纯化工艺。方法：采用正交实验设计,对栀子中栀子总环烯醚萜苷的纯化工艺进行了优化,以栀子苷标示栀子总环烯醚萜苷,采用HPLC法测定其含量,作为工艺筛选时的评价。结果：确立了栀子总环烯醚萜苷的纯化工艺,该工艺稳定可行。     

一种低延迟的可扩展调度算法

提出了一种基于阈值的分布式迭代算法。与现有算法不同的是,该算法针对可扩展网络交换调度结构的特点,为处于最高优先级的调度器安排了2次迭代,第1次迭代用阈值方法找出一些较长的VOQ（虚拟输出队列）,并在最高优先级时隙之前的一个时隙完成,以缩短信号的处理时间。仿真结果表明,该算法与现有算法相比,在大流量的uniform流量模式下,延时性能和吞吐率获得了明显的提高。同时,该算法的硬件代价小,有效地实现了性能和复杂度的良好折中。     

精密两维转镜的动力学仿真与控制误差分析

精密两维转镜作为激光角度欺骗干扰半实物仿真试验系统中模拟弹目、弹干扰视线运动的重要设备,其控制误差是影响视线运动模拟精度的重要因素,进而影响半实物仿真试验精度。以多体系统动力学方法推导了精密两维转镜的机电分析动力学模型,采用计算力矩法设计了两维转镜的轨迹跟踪控制器,并在Matlab/Simulink环境中对建立的反映转镜动态特性的数学模型进行了仿真,转镜方位、俯仰轴对等效正弦输入信号的角位置跟踪误差分别为2.2 mrad与3.5 mrad,结果表明:模型可实现对引导输入的角位置信号的高精度跟踪控制。