InAs基范德华异质结界面电荷转移特性第一性原理计算的研究进展

由低维InAs材料和其他二维层状材料堆叠而成的垂直范德华异质结构在纳米电子、光电子和量子信息等新兴领域中应用广泛。探索跨结界面的电荷转移机制对于全面理解该类器件的非凡特性至关重要。第一性原理计算在揭示界面电荷转移特性与各种能量稳定型InAs基范德华异质结的电、光、磁等原理物理特性和器件性能变化之间的内在关系方面发挥着不可比拟的作用。文中梳理、总结和探讨了近年来InAs基范德华异质结间界面电荷转移特性的理论研究工作与潜在的功能应用,提出在理论方法和计算精度方面大力发展第一性原理计算的几个途径,为更好地开展InAs基范德华异质结的基础科学研究和应用器件设计提供可借鉴的量化研究基础。     

InPBi禁带下红外光致发光效率的Bi组分依赖研究

稀Bi半导体InPBi的光致发光（Photoluminescence, PL）主要来自缺陷能级跃迁过程,具有红外长波长、大线宽和高辐射强度等特点,因而引发广泛兴趣。针对InPBi的红外发光效率问题,本文研究了不同Bi组分InPBi的激发功率依赖红外PL光谱演化规律。实验发现,随着Bi组分增大,PL线型发生显著变化,导致发光波长总体红移;同时激发功率依赖的PL积分强度演化分析表明,发光效率随Bi组分先增大然后下降,在0.5%组分时发光效率达到峰值。发光效率增大一方面归因于Bi捕获空穴降低非辐射复合,另一方面来自Bi的表面活性剂效应;而高Bi组分引入过多缺陷从而抑制了Bi的优势,导致发光效率下降。这些结果或有助于理解InPBi的红外发射性能,表明InPBi具有红外光电子应用前景。     

Semi-supervised transformable architecture search for feature distillation

Pattern Analysis and Applications - The designed method aims to perform image classification tasks efficiently and accurately. Different from the traditional CNN-based image classification methods,...     

Weakly supervised temporal action localization with proxy metric modeling

Temporal localization is crucial for action video recognition. Since the manual annotations are expensive and time-consuming in videos, temporal localization with weak video-level labels is challenging but indispensable. In this paper, we propose a weakly-supervised temporal action localization approach in untrimmed videos. To settle this issue, we train the model based on the proxies of each action class. The proxies are used to measure the distances between action segments and different original action features. We use a proxy-based metric to cluster the same actions together and separate actions from backgrounds. Compared with state-of-the-art methods, our method achieved competitive results on the THUMOS14 and ActivityNet1.2 datasets.     

Adaptive full order sliding mode control for electronic throttle valve system with fixed time convergence using extreme learning machine

Neural Computing and Applications - This paper proposes a novel extreme learning machine (ELM)-based fixed time adaptive trajectory control for electronic throttle valve system with uncertain...     

Study on the preparation and microstructure of a single-crystal hollow turbine blade

This paper studied the structural design of a ceramic core and a blade, ceramic core localization, shell preparation, casting process, core leaching technology, and the heat treatment process of a single-crystal hollow turbine blade. The results show that the single-crystal structure solidification sequence of the blade platform is consistent with the cooling sequence and the pulling-out direction of the blade. The primary dendrites were obviously enlarged with the increase of the blade thickness owing to the change in the local cooling rate. Besides, the γ′ phase had a high uniform size distribution ranging from 0.40 to 0.60?µm after heat treatment, and the cubic degree was more homogeneous in comparison with the as-cast microstructure, which are favorable for the superalloy structure. Moreover, γ′ phase size gradually increased and its quantity gradually reduced owing to the increase of the wall thickness in the growth direction.     

水热法以磷铁制备电池级磷酸铁的研究

采用水热法,以磷铁、磷酸、硝酸为原料制备电池级磷酸铁,并利用扫描电镜(SEM)、XRD、红外光谱(FTIR)、TG-DSC以及电化学测试等手段,表征产品的形貌、晶体结构、分子结构和电化学性能,研究了反应过程中硝酸浓度、反应温度、时间及体系浓度对产品性能的影响。实验结果表明:以磷铁为原料,用水热法在一定实验条件下制备的FePO_4·2H_2O产品为正磷酸铁,且产品中含有多种微量金属元素,这有效利用了磷铁中的微量元素,改善了磷酸铁及后续制备的磷酸铁锂的电化学性能。以此为原料通过高温固相法合成的LiFePO_4/C的首次放电容量为148.9mAh/g,具有良好的电化学性能。