CO-OFDM系统中利用阈值功率点改进的后向传输补偿算法

采用后向传输(BP)补偿算法补偿相干光正交频分复用(CO-OFDM)通信系统的非线性损伤是一种具有应用前景的方法。本文针对后向传输(BP)补偿算法计算复杂度高的问题,根据相干光正交频分复用(CO-OFDM)系统中非线性损伤与光功率的关系,通过选取合适的阈值功率点降低BP补偿算法的高计算复杂度。仿真结果表明,提出的方法可以大大降低BP补偿算法的计算复杂度,同时克服了传统算法过补偿的缺点,系统性能也得到提升。在100Gbit/s的CO-OFDM系统中,采用衰减因子为0.2dB/km的零色散光纤,信号传输3 200km(32×100km),光信噪比(OSNR)为16dB时,在选取合适的阈值功率点后,所需的BP补偿步骤数目由传统算法N=61降低为N=13,计算复杂度仅为原来的13/61。此外,采用改进的BP补偿算法补偿之后,系统的Q因子增加了0.204dB。     

A blind signal separation method for single-channel electromagnetic surveillance system

In this paper, a blind signal separation (BSS) methodology for simultaneously received multisystem frequency-overlapped signals in a single-channel (SC) electromagnetic surveillance system is proposed using fast independent component analysis (FastICA) in a dynamical embedding (DE) framework. Firstly, an appropriate DE matrix is constructed out of a series of delay vectors from the SC recording. The lag-time and the dimensional of embedding matrix setting principal are introduced in details. Next, multiple independent components (ICs) are calculated by decomposing the embedding matrix through FastICA algorithm, and ICs can be regarded as a convenient expansion basis of the original signals. Then, these ICs are projected back into the measurement space. After that, these projected ICs are classified and used for recovering the sources of interest based on their independent nature and their power density spectrum. Numerical simulation results obtained in evaluating the proposed methodology’s performance confirmed the effectiveness of the proposed algorithm.     

An oligothiophene dye with triphenylamine as side chains for efficient dye-sensitized solar cells

A novel oligothiophene-cyanoacrylic acid photosensitizer with two triphenylamine side chains (7T-2TPA) is designed and synthesized for dye-sensitized solar cells. 7T-2TPA exhibits broad (250-600 nm) and strong absorption (ε = 5.0 × 10⁴ L mol⁻¹ cm⁻¹ at 496 nm). The optical band gap (E_g) is estimated from the onset absorption edge to be 2.07 eV. The oxidation potential E_ox and reduction potential E_red vs NHE of the dye is 0.93 and −1.14 V, respectively. Dye-sensitized solar cell (DSSC) based on 7T-2TPA exhibits an open-circuit voltage (V_oc) of 724 mV, a short-circuit current density (J_sc) of 16.28 mA cm⁻², a fill factor (FF) of 0.684 and a power conversion efficiency of 8.06%. The efficiency of 8.06% is similar to that for widely used N719-based cell fabricated and measured under the same conditions.     

A new fast motion estimation algorithm based on the loop–epipolar constraint for multiview video coding

There lie geometric constraints between neighboring frames in multiview video sequences. The geometric constraints are valuable for reducing spatial and temporal redundancy in multiview video coding (MVC). In this paper, we propose a new fast motion estimation algorithm based on the loop–epipolar constraint which combines loop and epipolar constraints. A practical search technique is designed according to the characteristics of the loop–epipolar constraint. Experimental results show that the proposed algorithm is efficient for sequences under different multiview camera setups.     

利用ActiveX实现设备监控信息流的旁路捕获

在工作实践中,通常依据基带终端工作日志对设备出现的问题和故障现象进行分析检查,但是由于工作日志中的监控信息流要素记录不完整,或者在相对完整的工作日志记录中不能得到第三方的信息验证,给问题分析检查工作带来了一定的困难。另外,虽然市面上有一些网络抓包软件,但是专业的针对性不太强,大多是英文版,使用不方便。为了提高问题分析验证的能力,通过开发具有独立性好、针对性强的ActiveX控件,实现了基带终端监控信息流的旁路记录与分析,是一种简便有效的工作手段。通过研究分析基带终端的监控信息流图,进行了实现网络数据抓包功能的ActivX控件设计,给出了一个基带终端监控信息流的旁路捕获软件的应用实例。     

标准单元版图综合工具PLS

文章介绍了一种标准单元版图综合工具（ｃｅｌｌ ｌａｙｏｕｔ ｓｙｎｔｈｅｓｉｓ ｓｙｓｔｅｍ）,这是一种完全自动化的ＥＤＡ工具,它能根据输入单元电路网表和设计规则及单元库高度等参数自动生成符合设计要求且满足设计规则的单元版图。系统采用了改进的布图模式,得出了面积和电性能更加优化的单元版图。文中介绍了系统的设计流程,分析了系统采用的核心布局布线算法,以及在算法实现过程中为适应单元版图的特点和提高效率     

亚半微米投影光刻物镜的研究设计

介绍了分步重复投影光刻业半微米光刻物镜光学和机械结构研究设计、设计结果,以及公差控制。指出技术指标已达到：数值孔径ＮＡ＝０．６３、工作波长λ＝３６５ｎｍ、倍率５ｘ、工作分辨力Ｒ≤０．３５μｍ,设计和镜所用透镜片数最少,无胶合件,并具有暗场同轴对准和温度气压控制补偿功能。     

一种5.8 GHz磁控管谐振系统的模拟分析

利用HFSS结合等效电路对一种18叶片5.8 GHz磁控管的谐振系统进行了冷态模拟与分析,利用Master/Slave边界条件对磁控管谐振腔模型进行了改进,对叶片端部尺寸对磁控管谐振系统的影响进行了分析,分析结果与实验结果相吻合。为磁控管谐振系统的设计提供了依据。     

基于程序集成及响应面模型的电机冷却性能优化

建立某60 kW电动汽车用永磁同步电机模型,理论分析得到最佳流道条数以及流道参数取值范围。以冷却流道宽度a、高度b作为设计变量,电机温升和流道进出口压差作为目标函数,通过Isight集成网格变形软件Sculptor和CFD计算软件Fluent,应用拉丁超立方设计方法创建样本点,并进行数据的自动提交仿真计算。根据得到的数据建立响应面模型,采用多岛遗传算法对近似模型寻优。优化后,电机温升和进出口压差分别下降了6.01%、6.81%,电机的性能和安全运行得到了保障。     

UVGI技术在洁净空调系统中的应用

本文介绍洁净空调(CC&AC)系统微生物污染的发生及危害,论述国內外紫外辐照消毒(UVGI Ultraviolet Germicidal Irradiation)技术在CC&AC系统中的研究及应用情况;并通过对各种空气消毒处理手段的对比,说明现代UVGI技术在控制微生物的生长传播和节能方面的重要性。