Synthesis,structural and luminescence properties of near white light emitting Dy-doped Y2CaZnO5 nanophosphor for solid state lighting

Novel near white light emitting Y₂CaZnO₅ (YCZ) nanocrystalline powders doped with Dy³⁺ ions were synthesized via the citrate gel combustion method. The structure of the compound is found to be triclinic with a particle size in the range of 20–30 nm. Luminescence properties have been characterized using photoluminescence (PL), excitation spectra and decay time measurements. The PL spectra have shown a broad blue band due to ⁴F_9/2→⁶H_15/2 transition and sharp yellow band corresponding to ⁴F_9/2→⁶H_13/2 transition of Dy³⁺ ions. From the concentration dependent PL studies, the optimum concentration of Dy³⁺ ions in YCZ is found to be 1.0 mol%, where intense near white light emission was observed. The Dy³⁺:YCZ nanophosphor has shown relatively better white color properties than the reported Dy³⁺:Y₂O₃ nanophosphor. The yellow to blue intensity ratios, CIE chromaticity coordinates and correlated color temperature studies have shown the possibility of using this compound for white light emission.     

Improvement of carrier diffusion length in silicon nanowire arrays using atomic layer deposition

To achieve a high-efficiency silicon nanowire (SiNW) solar cell, surface passivation technique is very important because a SiNW array has a large surface area. We successfully prepared by atomic layer deposition (ALD) high-quality aluminum oxide (Al₂O₃) film for passivation on the whole surface of the SiNW arrays. The minority carrier lifetime of the Al₂O₃-depositedSiNW arrays with bulk silicon substrate was improved to 27 μs at the optimum annealing condition. To remove the effect of bulk silicon, the effective diffusion length of minority carriers in the SiNW array was estimated by simple equations and a device simulator. As a result, it was revealed that the effective diffusion length in the SiNW arrays increased from 3.25 to 13.5 μm by depositing Al₂O₃ and post-annealing at 400°C. This improvement of the diffusion length is very important for application to solar cells, and Al₂O₃ deposited by ALD is a promising passivation material for a structure with high aspect ratio such as SiNW arrays.     

凸轮机构磨损数值仿真软件研制

根据零件磨损过程一般数值仿真方法 ,以凸轮机构为研究对象 ,开发出不同类型凸轮磨损仿真软件 ,可实现不同极根条件下的凸轮磨损寿命预测、参数优化和状态监测等功能。     

Fluorolog-Tou-3荧光光谱仪寿命测量统介绍

本文介绍了美国 EG＆G公司生产的 Fluorolog—Tau—3荧光光谱仪寿命测量系统的功能及其工作原理。     

电子元器件贮存可靠性评估与预测的贝叶斯方法

基于电子元件寿命试验的二项型数据信息,提出了电子元件贮存可靠性评估与预测的贝叶斯方法.利用环境因子将电子元件产品在不同贮存条件下的试验数据进行折合,依据贝叶斯理论对小样本下可能出现的数据"数据倒挂"进行预处理,并评估出其在各已知贮存时间点上的可靠度,再运用配曲线法得到产品的贮存寿命分布,进而对其贮存可靠度进行合理预测.最后,通过一个实例说明了方法的可行性.     

Hot wire chemical vapor deposition: limits and opportunities of protecting the tungsten catalyzer from silicide with a cavity

Hot Wire Chemical Vapor Deposition (HW-CVD) is one of the most promising techniques for depositing the intrinsic microcrystalline silicon layer for the production of micro-morph solar cells. However, the silicide formation at the colder ends of the tungsten wire drastically reduces the lifetime of the catalyzer, thus limiting its industrial exploitation. A simple but interesting strategy to decrease the silicide formation is to hide the electrical contacts of the catalyzer in a long narrow cavity which reduces the probability of the silane molecules to reach the colder ends of the wire. In this paper, the working mechanism of the cavity is elucidated. Measurements of the thickness profile of the silicon deposited in the internal walls of the cavity have been compared with those predicted using a simple diffusion model based on the assumption of Knudsen flow. A lifetime study of the protected and unprotected wires has been carried out. The different mechanisms which determine the deterioration of the catalyzer have been identified and discussed.     

Large-area organic photovoltaic module—Fabrication and performance

Here we describe the fabrication of the largest (233 cm² total area) organic photovoltaic (OPV) module (polymer:fullerene) to be certified by the National Renewable Energy Laboratory (NREL). OPV solar cells were fabricated at Plextronics by spin coating a blend of poly 3-hexylthiophene-2,5 diyl (P3HT) and [6,6] phenyl C₆₁ butyric acid methyl ester (PCBM) on top of our hole transport layer (HTL), Plexcore^® OC. In laboratory-scale devices (0.09 cm²), this system routinely exhibits power conversion efficiencies exceeding 3.7%. This P3HT:PCBM active layer and HTL ink system was used to scale up to the larger area module (15.2 cm×15.2 cm module size, i.e. 233 cm² total area; 108 cm² active area), which was certified by NREL as having 1.1% total area efficiency (3.4% active area efficiency).     

Zur Übertragbarkeit der Schwingfestigkeitseigenschaften im Örtlichen Konzept

Transferability of the properties of fatigue in the local approach This article deals with the uncertainty of lifetime prediction. There are to reasons for still unsatisfying calculation results, known as transferability problems. The first appears when using strength under constant amplitude loading for the prediction of operational loaded structures. The second transferability problem exists only in the local strain approach where the strength of the unnotched small specimen is assumed to be valid for the real component as well. This difficulty is dealt with by separating the independent influences and its individual consideration. The microstructural mechanics influence is derived by a statistical evaluation of experimental data. The proposed concept for regarding the microstructural support effect allows o derive a strain‐life‐curve for an individual component. The results of verification look promising.     

云母钛珠光颜料的正电子寿命谱研究

用正电子湮没技术测量了云母钛珠光颜料的正电子寿命和强度与煅烧温度，包覆量等的关系，并与Ｘ射线衍射，透射电镜等方法进行了比较。     

Influence diagnostics in log-Birnbaum-Saunders regression models with censored data

In this paper we discuss log-Birnbaum-Saunders regression models with censored observations. This kind of model has been largely applied to study material lifetime subject to failure or stress. The score functions and observed Fisher information matrix are given as well as the process for estimating the regression coefficients and shape parameter is discussed. The normal curvatures of local influence are derived under various perturbation schemes and two deviance-type residuals are proposed to assess departures from the log-Birnbaum-Saunders error assumption as well as to detect outlying observations. Finally, a data set from the medical area is analyzed under log-Birnbaum-Saunders regression models. A diagnostic analysis is performed in order to select an appropriate model.