氧化锌压敏电阻老化过程中非线性系数变化的研究

根据氧化锌压敏电阻(MOV)的非线性特征,结合双肖特基(Schottky)势垒理论和氧化锌陶瓷在小电流区的导电机制,提出了氧化锌压敏电阻老化劣化过程中必然伴随着非线性系数α的变化的结论.针对一种型号的MOV,通过大量实验数据分析得出:在不同老化劣化实验条件下,MOV的非线性系数α均随劣化程度的增加而呈下降趋势;在标称电...     

一种基于退化数据的元器件可靠性定量检验方法研究

针对高可靠元器件可靠性鉴定中缺乏可靠性级别定量评价的问题,基于失效物理,分析了键合强度参数退化及失效判据,并给出了退化模型的数学表达和参数估计方法,研究基于退化量分布的可靠性定量检验方法,并采用AD厂家的AD524SD作为试验器件,进行了相应的试验分析和验证。结果表明,提出的高可靠性级别器件鉴定检验方法具有很好的工程适用性和应用价值。     

Gaining Insight into the Effect of Organic Interface Layer on Suppressing Ion Migration Induced Interfacial Degradation in Perovskite Solar Cells

Ion migration induced interfacial degradation is a detrimental factor for the stability of perovskite solar cells (PSCs) and hence requires special attention to address this issue for the development of efficient PSCs with improved stability. Here, an “S‐shaped, hook‐like” organic small molecule, naphthalene diimide derivative (NDI‐BN), is employed as a cathode interface layer (CIL) to tailor the [6,6]‐phenylC61‐butyric acid methylester (PCBM)/Ag interface in inverted PSCs. By realizing enhanced electron extraction capability via the incorporation of NDI‐BN, a peak power conversion efficiency of 21.32% is achieved. Capacitance–voltage measurements and X‐ray photoelectron spectroscopy analysis confirmed an obvious role of this new organic CIL in successfully blocking ionic diffusion pathways toward the Ag cathode, thereby preventing interfacial degradation and improving device stability. The molecular packing motif of NDI‐BN further unveils its densely packed structure with π–π stacking force which has the ability to effectually hinder ion migration. Furthermore, theoretical calculations reveal that intercalation of decomposed perovskite species into the NDI clusters is considerably more difficult compared with the PCBM counterparts. This substantial contrast between NDI‐BN and PCBM molecules in terms of their structures and packing fashion determines the different tendencies of ion migration and unveils the superior potential of NDI‐BN in curtailing interfacial degradation.     

Impact of Processing on Structural and Compositional Evolution in Mixed Metal Halide Perovskites during Film Formation

Understanding crystallization processes and their pathways in metal‐halide perovskites is of crucial importance as this strongly affects the film microstructure, its stability, and device performance. While many approaches are developed to control perovskite formation, the mechanisms of film formation are still poorly known. Using time‐resolved in situ grazing incidence wide‐angle X‐ray scattering, the film formation of perovskites is investigated with average stoichiometry Cs_0.15FA_0.85PbI₃, where FA is formamidinium, using the popular antisolvent dropping and gas jet treatments and this is contrasted with untreated films. i) The crystallization pathways during spin coating, ii) the subsequent postdeposition thermal annealing, and iii) crystallization during blade coating are studied. The findings reveal that the formation of a nonperovskite FAPbI₃ phase during spin coating is initially dominant regardless of the processing and that the processing treatment (e.g., antisolvent dropping, gas jet) has a significant impact on the as‐cast film structure and affects the phase evolution during subsequent thermal treatment. It is shown that blade coating can be used to overcome the nonperovskite phase formation via solvothermal direct crystallization of perovskite phase. This work shows how real‐time investigation of perovskite formation can help to establish processing–microstructure–functionality relationships.     

RBF网络用于性能退化的可靠性评估

针对无法用数学式准确描述退化量与环境因子间复杂非线性关系的问题,提出了一种基于RBF网络的退化轨迹建模方法.利用RBF网络能够逼近任意非线性函数的特性,进行退化轨迹的建模,并结合失效值预测产品寿命.将所有估计寿命作为完全失效数据进行可靠性评估,有效地解决了失效数据少的问题.通过对疲劳裂纹增长数据的RBF网络建模分析,证明RBF网络具有很好的函数逼近能力,寿命预测结果非常理想.经验证,在更少的退化数据下,RBF网络仍能够较好地模拟退化轨迹,寿命预测精度较高.     

Stability of Flip-Chip Interconnects Assembled with Al/Ni(V)/Cu-UBM and Eutectic Pb-Sn Solder During Exposure to High-Temperature Storage

The thermal stability of flip-chip solder joints made with trilayer Al/Ni(V)/Cu underbump metalization (UBM) and eutectic Pb-Sn solder connected to substrates with either electroless Ni(P)-immersion gold (ENIG) or Pb-Sn solder on Cu pad (Cu-SOP) surface finish was determined. The ENIG devices degraded more than 50 times faster than the Cu-SOP devices. Microstructural characterization of these joints using scanning and transmission electron microscopy and ion beam microscopy showed that electrical degradation of the ENIG devices was a direct result of the conversion of the as-deposited Ni(V) barrier UBM layer into a porous fine-grained V₃Sn-intermetallic compound (IMC). This conversion was driven by the Au layer in the ENIG surface finish. No such conversion was observed for the devices assembled on Cu-SOP surface finish substrates. A resistance degradation model is proposed. The model captures changes from a combination of phenomena including increased (1) intrinsic resistivity, (2) porosity, and (3) electron scattering at grain boundaries and surfaces. Finally, the results from this study were compared with results found in a number of published electromigration studies. This comparison indicates that degradation during current stressing in the Pb-Sn bump/ENIG system is in part due to current-crowding-induced Joule heating and the thermal gradients that result from localized Joule heating.     

多步联合检测技术在SCDMA系统中的应用

同步CDMA系统接近满码道工作时，由于信噪比恶化，联合检测技术不能满足系统性能的要求。多步联合检测(MSJD)有效地解决了这个问题，大大提高了系统的性能。本文研究了多步联合检测技术，在多步联合检测算法的基础上提出了改进的并行多步联合检测算法，减小了系统的延时；并把天线的接收分集和多用户检测技术相结合，提高了多径衰落信道下的传输可靠性。     

Study on inorganic oxidants assisted sonocatalytic degradation of Resazurin dye in presence of β-SnWO4 nanoparticles

This work presents about the study of inorganic oxidants assisted sonocatalytic degradation of Resazurin (RZ) dye in the presence of β-SnWO₄ nanoparticles. The catalysts were synthesized via a surfactant free sonochemical method. Physical properties of the as-prepared β-SnWO₄ nanoparticles were analyzed by XRD and FE-SEM. The dispersion property and particle size were analyzed by Zeta potential and Particle size analyzer. The degradation of RZ was analyzed in the presence and absence of common oxidants such as PMS (peroxymonosulfate) and H₂O₂ (hydrogen peroxide). The result shows that the RZ was first mineralized to Resorufin and it was degraded to simple molecule in the presence of β-SnWO₄. 75% of degradation efficiency was achieved in presence of β-SnWO₄, while in addition of H₂O₂ and PMS, the efficiency was increased up to 93% and 85% respectively. Our results will pave a new opening in degradation of poisonous dye using inorganic common oxidants.     

STC power for 15 MW of PV comparing nameplate,initial power and power after 4 years

To date, the majority of quality controls performed at PV plants are based on the measurement of a small sample of individual modules. Consequently, there is very little representative data on the real Standard Test Conditions (STC) power output values for PV generators. This paper presents the power output values for more than 1300 PV generators having a total installed power capacity of almost 15.3 MW. The values were obtained by the INGEPER‐UPNA group, in collaboration with the IES‐UPM, through a study to monitor the power output of a number of PV plants from 2006 to 2009. This work has made it possible to determine, amongst other things, the power dispersion that can be expected amongst generators made by different manufacturers, amongst generators made by the same manufacturer but comprising modules of different nameplate ratings and also amongst generators formed by modules with the same characteristics. The work also analyses the STC power output evolution over time in the course of this 4‐year study. The values presented here could be considered to be representative of generators with fault‐free modules. Copyright © 2012 John Wiley & Sons, Ltd.