电网谐波对继电保护的影响与预防措施分析

先对电网谐波问题进行了分析,讨论了电网谐波对继电保护的影响以及对继电保护装置的影响,最后分析了目前预防谐波对继电保护影响的措施,并提出了可行性建议.     

北电ATM网络运维管理经验

北电ATM交换机的性能管理参数极为丰富，通过对其进行合理配置，可优化网络运行质量。文中介绍通过对北电ATM交换机上的Atmif和Aallces部件参数的合理配置，实现了SVC业务的优化路由选择，改善了仿真电路传输质量，并具体阐明了实际配置方法及注意事项。     

基于等效瞬时电感判别变压器励磁涌流的新算法

基于变压器铁心磁导率在励磁涌流与内部故障时变化情况的不同,应用瞬时励磁电感和等效瞬时电感的概念,可有效判别变压器励磁涌流.但是,现有的等效瞬时电感计算方法存在较大的误差,对准确判别变压器励磁涌流构成了威胁.为此,提出了改进型的等效瞬时电感计算方法,有效考虑了等效电阻的影响,极大地改善了计算精度.以此为基础,给出了2种判别励磁涌流方案,即时域法和频域法.通过动模实验,对改进型算法和现有的近似算法进行了对比研究.结果表明,应用改进型算法求取的等效瞬时电感更为准确,使时域法和频域法的判别精度得到了极大的改善,有力证实了文中所提出的新算法正确、可行、有效.     

Revealing and Eliminating the Light-Soaking Issue in Metal Oxide-Based Inverted Organic Solar Cells

Inverted organic solar cells (i-OSCs) provide an exciting opportunity for commercialization owing to their excellent device air stability. However, light soaking (LS) issue generally occurs in metal oxide based i-OSCs, causing drastically decreased performance. The underlying root of LS effect is not clearly clarified until now. Herein, it is demonstrated that the surface oxygen defects on metal oxide nanoparticles, such as chemisorbed superoxide (O²⁻) and hydroxide (OH) dangling bonds, are the main reasons for LS issue in i-OSCs. The O²⁻ layer induces band bending at the cathode interface and increases the work function (WF) of metal oxide, thus leading to inefficient charge transport. The dangling bonds serve as interfacial trap states and cause non-radiative recombination, thus leading to the reduced open circuit voltage (V_oc). With ultraviolet (UV) illumination, the surface oxygen defects are interacted with photogenerated carriers, thereby improving the photovoltaic performance. Additionally, UV pretreatment of metal oxide films is employed to eliminate the LS issue and the resulting device yields significantly improved fill factors from 50.20% to 73.50% in the pristine SnO₂ based i-OSCs. This study reveals the origin of LS effect in i-OSCs and proposes a suggested model for LS mechanism.     

A Low On-Resistance SOI LDMOS using a Trench Gate and a Recessed Drain Ge Rui(葛锐), Luo Xiaorong(罗小蓉)?, Jiang Yongheng(蒋永恒), Zhou Kun(周坤),

本文提出了一种超低比导通电阻(R_on,sp) SOI槽栅凹漏MOSFET(TGRD MOSFET)。正向导通时,槽栅和凹漏的结构增加了导电区域,缩短了电流流经的路径,从而降低了比导通电阻。并且此结构中采用了RESURF结构提高了漂移区浓度,进一步降低了比导通电阻。当TGRD MOSFET的半个元胞尺寸为6.5μm时,它的击穿电压为97V,R_on,sp为0.985mΩ.cm₂。与SOI槽栅MOSFET(TG MOSFET)和常规MOSFET(Conventional MOSFET)相比,在相同的BV下,TGRD MOSFET的R_on,sp分别地降低了46%和83%。或者在相同的R_on,sp下,与SOI槽栅槽漏MOSFET(TGTD MOSFET)相比, BV提高了37%。     

基于RBF神经网络的机抖激光陀螺零偏的温度补偿的研究

温度偏置漂移是存在于激光陀螺中使得输出信号产生较大偏置误差的一种不可忽略因素,准确地辨识漂移并有效地对其进行补偿直接关系到激光陀螺的测量精度.通过温度实验研究了机抖激光陀螺的温度特性,采用RBF网络进行温漂辨识.温漂辨识可以通过离线事先学习,因而在多种学习方法中选择了简单易行、精度高且运算速度快的正交最小二乘(OLS)法.通过实验验证,采用RBF网络及其OLS学习算法可以快速、有效、高精度地辨识并补偿温漂.     

衬底表面处理对原子层沉积方式生长铂金薄膜的影响

在这篇文章中,我们利用原子层沉积(ALD)的方式在硅衬底上生长铂金(反应源是(CH₃C₅H₄Pt(CH₃)₃)和氧气)。将经过氢氟酸处理和氧气处理的两种类型硅衬底进行生长对比实验来探究衬底表面处理对原子层沉积方式生长铂金薄膜的影响。相对于经氧化处理的硅衬底来说,在氢氟酸处理的硅衬底上淀积铂金薄膜有较长的滞后时间且生长过程不同。此外,即使在原子层沉积铂金薄膜实验之前利用氢氟酸处理硅衬底以去除天然氧化层,淀积实验完成后在铂金和硅衬底界面处仍有一层中间氧化层。文章解释了导致这种差异性的原因。     

Crumple Durable Ultraflexible Organic Solar Cells with an Excellent Power-per-Weight Performance

Ultraflexible and ultra-lightweight organic solar cells (OSCs) have attracted great attention in terms of power supply in wearable electronic systems. Here, ultrathin and ultra-lightweight OSCs, with a total thickness of less than 3 µm, with excellent mechanical properties in terms of their flexibility and ability to be stretched are demonstrated. A stabilized power conversion efficiency (PCE) of 15.5% and unprecedented power-per-weight of 32.07 W g⁻¹ at a weight of 4.83 g m⁻² is achieved, which represents one of the best-performing OSCs based on ultrathin foils substrate reported to date. The ternary strategy introduces the third component of amorphous conformation of the PC₇₁BM molecule, which can slightly reduce crystallization and aggregates without decreasing the electron mobility, thereby reducing rigidity and brittleness of the active layer. The increase in the ductility of the active layer significantly improves the mechanical flexibility of the device, resulting in over 90% retention in the PCE after 200 stretching–compression cycles. In addition, the ternary device exhibits excellent stability when stored in a N₂-filled glove box, resulting in the PCE retaining over 95% of its initial efficiency even after 1000 h. This ultraflexible and ultra-lightweight photovoltaic foils constitute a major step toward the integration of power supply into malleable electronic textiles.     

DVB-S2中LDPC编解码分析

本文在简要介绍LDPC码的基础上，就DVB—S2标准中LDPC编解码过程进行了详细的分析，指出了值得关注和研究的元素。     

FDTD Study on Back Scattering of Conducting Sphere Coated with Double-Negatibe Metamaterials

The shift operator method in finite-difference time-domain method for anisotropic double-negative (DNG) metamaterials is derived. The problem which incorporates both anisotropy and frequency dispersion at the same time is solved for the electromagnetic wave propagation in DNG media. By comparing with the mie series solution, the numerical verification of the method and program are confirmed by computing the back scattering of isotropic unmagnetized plasma sphere. The back scattering of conducting sphere coated with DNG media with different parameters is computed by using the shift operator method. One finds that the degree of DNG media’s match and isotropy plays important parts in the decrease of the back scattering of the conducting sphere.