AES Analysis of Ce and P Cosegregation at Grain Boundaries

The chemical state of grain boundary cosegregation of Ce and P in Fe-P-Ce alloy system was studied bymeans of Auger Electron Spectroscopy(AES).The Auger peaks of Ce segregated at grain boundaries are foundwithin the range of 60～180 eV.By comparing with the Auger spectra of the Fe-Ce-P intermetallic compound,it is supposed that there is a two-dimensional interfacial phase at grain boundaries with Ce and P cosegregationwhich is similar to the structure of the Fe-Ce-P compound.     

强夯置换法施工技术探讨

介绍了强夯置换法的施工原理,探讨了强夯置换法的设计及施工,指出强夯置换法能提高地基的强度、降低其压缩性,并改善其抵抗振动液化的能力和消除土的湿陷性,以期为该技术的合理使用提供技术指导和理论依据。     

我国大气尘计数浓度的特点

分析了我国132个地区大气尘计数浓度的检测结果,发现我国大气尘浓度分布规律没有明显变化,指数仍为2.15,但数值比过去降低40%左右.     

基于BP神经网络的视频镜头突变检测算法*

对于数字视频镜头突变切换的检测,一般有模板匹配法、直方图法等基本算法,但这些算法都需要确定阈值,并在实际检测中通常达不到较高的检测精度。提出了一种新的基于BP神经网络的视频镜头突变检测算法,该算法选取模板匹配二次差分和直方图二次差分作为特征,利用神经网络的自组织、自学习能力实现镜头突变检测,然后以闪光检测来提高检测的可靠性。实验结果表明,该算法能够有效地检测视频的镜头突变,无须设定阈值,具有计算简单、易于实现的优点。     

Thermodynamically Stable Synthesis of Large‐Scale and Highly Crystalline Transition Metal Dichalcogenide Monolayers and their Unipolar n–n Heterojunction Devices

Transition metal dichalcogenide (TMDC) monolayers are considered to be potential materials for atomically thin electronics due to their unique electronic and optical properties. However, large‐area and uniform growth of TMDC monolayers with large grain sizes is still a considerable challenge. This report presents a simple but effective approach for large‐scale and highly crystalline molybdenum disulfide monolayers using a solution‐processed precursor deposition. The low supersaturation level, triggered by the evaporation of an extremely thin precursor layer, reduces the nucleation density dramatically under a thermodynamically stable environment, yielding uniform and clean monolayer films and large crystal sizes up to 500 µm. As a result, the photoluminescence exhibits only a small full‐width‐half‐maximum of 48 meV, comparable to that of exfoliated and suspended monolayer crystals. It is confirmed that this growth procedure can be extended to the synthesis of other TMDC monolayers, and robust MoS₂/WS₂ heterojunction devices are easily prepared using this synthetic procedure due to the large‐sized crystals. The heterojunction device shows a fast response time (≈45 ms) and a significantly high photoresponsivity (≈40 AW^?1) because of the built‐in potential and the majority‐carrier transport at the n–n junction. These findings indicate an efficient pathway for the fabrication of high‐performance 2D optoelectronic devices.     

Roll‐to‐Roll Production of Layer‐Controlled Molybdenum Disulfide: A Platform for 2D Semiconductor‐Based Industrial Applications

A facile methodology for the large‐scale production of layer‐controlled MoS₂ layers on an inexpensive substrate involving a simple coating of single source precursor with subsequent roll‐to‐roll‐based thermal decomposition is developed. The resulting 50 cm long MoS₂ layers synthesized on Ni foils possess excellent long‐range uniformity and optimum stoichiometry. Moreover, this methodology is promising because it enables simple control of the number of MoS₂ layers by simply adjusting the concentration of (NH₄)₂MoS₄. Additionally, the capability of the MoS₂ for practical applications in electronic/optoelectronic devices and catalysts for hydrogen evolution reaction is verified. The MoS₂‐based field effect transistors exhibit unipolar n‐channel transistor behavior with electron mobility of 0.6 cm² V^?1 s^?1 and an on‐off ratio of ≈10³. The MoS₂‐based visible‐light photodetectors are fabricated in order to evaluate their photoelectrical properties, obtaining an 100% yield for active devices with significant photocurrents and extracted photoresponsivity of ≈22 mA W^?1. Moreover, the MoS₂ layers on Ni foils exhibit applicable catalytic activity with observed overpotential of ≈165 mV and a Tafel slope of 133 mV dec^?1. Based on these results, it is envisaged that the cost‐effective methodology will trigger actual industrial applications, as well as novel research related to 2D semiconductor‐based multifaceted applications.     

机载数据记录处理信息系统的研究与实现

本文介绍了一种对飞机训练中的数据记录进行相关处理的信息系统.本信息系统是以标准数据格式为处理依据,产生实体对象进行处理的信息系统.本文阐述了系统的设计方案,并对系统的图象处理分系统、坐标处理分系统、文件处理分系统进行了介绍.     

A Diversity-based Selfish Node Detection Algorithm for Socially Aware Networking

Because mobile devices only have the limited resource in socially aware networking, some network nodes are unwilling to sacrifice their resource to forward messages to others for free, thus forming selfish nodes. However selfish nodes will cause dropping in the message delivery rate and affect the network performance, so this paper has proposed a diversity-based selfish node detection algorithm (DSNDA). Firstly, it mainly applies the node forwarding willingness mechanism to detect whether the node is selfish. If the node has the inadequate resource, that is, it cannot forward any messages for others; then it will be selfish. If the node’s resource is enough and the node has forwarded messages to other nodes, it indicates that the node is not selfish. Otherwise, DSNDA algorithm will use reputation mechanism to check the node further. If the node has broken faith, it indicates that the node is selfish. On the contrary the message confirmation mechanism will be employed to make the final check on the node. If a message does not be received or discarded after the node’s receiving it, which proves that it has selfish behaviour. If not, the node is normal. It can be proved by the simulation experiment and results that the DSNDA algorithm has significantly improved the delivery rate of messages, comparing with other algorithms. At the same time, reducing the network delay, thus verifying the feasibility of DSNDA.