Core–Shell Photoanodes for Photoelectrochemical Water Oxidation

Photoelectrochemical (PEC) water splitting into hydrogen and oxygen is a promising solution for the conversion and storage of solar energy. Because sluggish water oxidation is the bottleneck of water splitting, the design and preparation of an efficient photoanode is intensively investigated. Currently, all known photoanode materials suffer from at least one of the following drawbacks: ① low carriers separation efficiency; ② sluggish surface water oxidation reaction; ③ poor long-term stability; ④ insufficient water adsorption and gas desorption. Core–shell configurations can endow a photoanode with improved activity and stability by coating an overlayer that plays energetic, catalytic, and/or protective roles. The construction strategy has an important effect on the activity of a core–shell photoanode. Nonetheless, the mechanism for the improvement of performance is still ambiguous and is worthy of a closer examination. In this review, the successes and challenges of core–shell photoanodes for water oxidation, focusing on synthesis strategies as well as functionalities (facilitating carrier separation, surface reaction promotion, corrosion prevention, and bubble detachment) are explored. Finally, the perspectives of this class of materials in terms of new opportunities and efforts are discussed.     

软件无线电技术在雷达设计中的应用

软件无线电作为一种新的无线通讯概念，他的应用研究主要集中于军用通讯以及民用移动通讯领域。随着DDS，DSP，FPGA和ASIC等技术的发展，软件无线电技术在雷达信号的产生及处理等方面的应用已逐渐成熟，软件化雷达的实际应用已变得十分可行。软件无线电技术的应用使雷达系统具有可编程、可扩展、灵活性高的特点。本文将软件无线电的设计思想应用于雷达系统的设计中，并对系统的硬件设计、元器件选择及软件设计流程等进行了简单说明，给出了相应的实现方案。     

含有低温AlN插入层的厚膜GaN的氢化物气相外延生长

研究了采用低温氮化铝(LT-AlN)插入层的厚膜GaN的氢化物气相外延生长(HVPE),并比较了7nm厚的LT-AlN插入层在经过不同退火时间后对GaN膜生长的影响.结果表明,退火后的LT-AlN插入层表面形貌发生很大变化.在一定的退火条件下,AlN插入层能有效地改善HVPE生长的GaN外延层的结晶质量.     

Learning a Deep Metric: A Lightweight Relation Network for Loop Closure in Complex Industrial Scenarios

The similarity metric in Loop closure detection (LCD) is still considered in an old fashioned way, i.e. to pre-define a fixed distance function, leading to a limited performance. This paper proposes a general framework named LRN-LCD, i.e. a Lightweight relation network for LCD, which combines the feature extraction module and similarity metric module into a simple and lightweight network. The LRN-LCD, an end-to-end framework, can learn a non-linear deep similarity metric to detect loop closures from different scenes. Moreover, the LRN-LCD supports image sequences as input to speed up the similarity metric in real-time applications. Extensive experiments on several open datasets illustrate that LRN-LCD is more robust to strong condition variations and viewpoint variations than the mainstream methods.     

基于Freeman链码的岩心交叉裂缝分离算法

在石油地质领域中,裂缝研究是油气勘探的重点.而且,岩心裂缝统计参数分析的准确程度,对油气勘探开发和提升采收率都有着一定程度的影响.由于岩心裂缝中存在大量的交叉裂缝,会对裂缝的统计和计算裂缝的分布特征造成影响.因此,本文在识别岩心裂缝的基础上,通过改进Freeman链码直线检测算法,对细化后的交叉裂缝骨架进行分离;通过分...     

弹性光网络中结合预测的多维感知RSA算法

弹性光网络(EON)中的传统路由频谱分配(RSA)算法多考虑路由跳数或频谱资源占用情况,缺乏时域与相邻链路的信息有效利用.提出一种结合预测的多维感知RSA算法,对持续时间已知业务的历史时间信息通过后向传播神经网络预测未来业务的时间信息,在路由时综合考虑时间、频谱和相邻链路资源占用程度.仿真结果表明:与传统RSA算法相比...     

基于Bootstrap 法的机载浮标搜潜系统作战效能指标分析

为解决试验样本量较少导致评估精度较低的问题,引入Bootstrap方法对机载浮标搜潜系统部分指标进行评估。介绍对于成败型指标的目标发现率评估步骤,并对一定环境下的潜艇目标发现率、浮标信号有效接收距离和某分机灵敏度这3项有代表性的指标进行仿真。分析结果说明该方法确实能够提高评估精度。     

基于双方最优控制的微分策略制导

为了提高导弹攻击大机动目标的制导能力,文中提出了双边最优的微分策略制导律。并针对数学上难于求解的两点边值问题,创新性的采用了伴随方法进行求解。在导弹和目标均为一阶时间延迟下推导出微分对策制导的公式,通过与扩展比例导引、单边最优制导的仿真比较,考察脱靶量和控制能量两个指标,得出微分策略制导在理论上的先进性。     

基于Modelica语言的弹道导弹模型库开发

为实现弹道导弹仿真模型的快速建立,基于Modelica语言设计开发了弹道导弹模型库Missile Lib。文中简要描述了Modelica语言的特点,详细介绍了模型库的体系结构,与Simulink工具箱中的Aerospace Blockset模型库进行了比较,最后基于该库快速搭建了某弹道导弹仿真模型并进行仿真,结果得到验证,证明了模型库的实用性与模块的正确性。模型库模型种类丰富,实现了知识的重用与积累,基于该库可以快速搭建弹道导弹模型进行仿真,实现弹道导弹飞行性能的快速评估。     

新型稀土6063铝材热加工性能研究

采用高温拉伸、高温压缩试验方法,对新型稀土6063铝合金半连续铸造锭坯材进行热变形加工性能研究。通过拉伸变形抗力、伸长率、压缩变形量、冲击速度的测量比较,以及两类试验试样的形貌、形态观察对比,确定新型稀土6063铝合金半连续铸造锭坯材最佳热挤压加工温度区间为450~480℃;实施大变形、高速挤压与在线连续淬火工艺,最佳热挤压温度区间应控制在430~480℃。