多功能配电房状态监测传感器的设计

为提高配电房的环境监控力度和运维管理水平,设计了一款能实时监测多种气体浓度和温湿度的多功能传感器.对传感器的原理、电路设计、软件设计和功能参数等进行了详细介绍.传感器以STM32L151RDT6微处理器为主控芯片,以先进光谱和电化学技术为原理对多种气体同时进行检测,使用基于ZigBee(一种短距离无线传输协议)的无线传...     

Enhanced electrostatic energy storage achieved in BiFeO3-driven (Sr,Bi)TiO3 ceramics for high-voltage pulsed applications

The paradoxical relationship between ferroelectric polarization and dielectric breakdown to a great extent hinders the increase in energy storage properties of dielectric materials. A strategy of combining large polarization and high dielectric breakdown by composition optimization was designed in (Sr_0.7Bi_0.2)TiO₃–BiFeO₃ system. All ceramics show dense microstructures with fine grain sizes. A promising energy density of 3.67 J/cm³ with an efficiency of 89.1% can be obtained in 0.93(Sr_0.7Bi_0.2)TiO₃-0.07BiFeO₃ at 340 kV/cm. The energy density shows excellent temperature reliability in a wide temperature range till 160 °C and reliable fatigue endurance till 10⁵ cycles. This research expands the strategy of combing large polarization and dielectric breakdown for developing novel dielectrics used in pulse power electronics.     

风力发电场监控通讯标准IEC 61400-25及其设计思路

简要介绍IEC颁布的IEC 61400-25标准，给出了系统软件设计的思路。提出了模块化的系统构架；针对三种系统配置方式作出比较分析；为提高系统响应速度进一步讨论了数据存贮和检索的可选方式；最后对系统安全机制做出讨论并提出适当的解决方案     

Enhanced luminescence efficiency and thermal stability via introduction of non-rare earth Bi3+ in Gd5Si2BO13:Eu3+

A series of Gd₅Si₂BO₁₃:Eu³⁺ and non-rare earth Bi³⁺ ions doped Gd₅Si₂BO₁₃:Eu³⁺ phosphors was successfully synthesized via high-temperature solid-state method,and the as-obtained phosphors were studied on their phase structures,luminescence characteristics,thermal stability and luminescence lifetime.Transient fluorescence spectroscopy data show that the addition of Bi³⁺ can obviously enha...     

Mechanism of superior charge suppression behavior of Si3N4 ceramics at solid-gas interface

Recent study has found excellent bulk and surface insulation property of Si₃N₄ ceramic which make it potential to serve as key insulation component in various energy transmission apparatus. Charge accumulation at gas-solid interface is a critical insulation property but few relevant study on Si₃N₄ can be found. This contribution has investigated the surface charge property of Si₃N₄ ceramic compared to traditional insulation polymer under different electrical-thermal stress. Through its comparison with the electric field distribution, the main source of the surface charge accumulation is analyzed, indicating that the superior surface charge suppression performance of Si₃N₄ lies on its low carrier density and conduction barrier, which considerably prevent charge injection and suppress the normal electric field which drives the charge to the gas-solid interface. The proposed mechanism is also validated by the characterization on conducting and space charge property for Si₃N₄ as well as dynamic simulation on surface charge accumulation.     

基于海事VTS的智能航标船舶干预系统在500kV海南联网工程的应用

海底电缆工程是跨海电网建设工程的重要组成部分,海底电缆是不可或缺的电力“生命线”,实现了我国远距离传输电能的宏伟战略目标。随着海底电缆线路数量的不断增加,海底电缆常常由于复杂的海洋环境和各种外在的人文因素而常遭受到的各种类型和不同程度的破坏以及海底电缆在近海区域由于船锚钩挂造成的故障也越来越严重。本文针对海底电缆易受到船只的破坏,提出了海缆保护区智能航标应急干预处置的功能分析对海底电缆有着重要防护措施,对以后该类工程的实施具有一定的指导意义。     

Nucleation and growth of L12-Al3RE particles in aluminum alloys:A first-principles study

The internal mechanisms of nucleation and growth of L1₂-AI₃RE(RE=Sc,Y,La-Lu) second phases in Al alloys were investigated by combining first-principles calculations with quasi-harmonic approximation(QHA).The calculated results show that the diffusion rate D_s and chemical potential AG_V increase with the increase of temperature.With the increase of atomic number,the D_s and the strain energy ΔE_CSincrease firstly from Sc to La,and the...     

Adsorption of rare earth elements on organic matter in coal

The occurrence modes of rare earth elements(lanthanide and yttrium,abbreviated as REY) in coal are impo rtant both for coal geochemistry studies and the application potential of REY as a by-product of coalbased resources.In this study,the adsorption behaviors of REY on organic matter in coal were investigated by leaching tests using REY solution and ultra-low ash coal samples.On this basis,the adsorption mechanism of REY on organic matter in coal was also studied by molecular simulation calculat...     

Tuning structure and magnetic properties of table-like magnetocaloric effect in Er6MnSb2 by zirconium substitution

In this study,zirconium(Zr) successfully substituted for erbium(Er) in Er_6-xZr_xMnSb₂(x=0,0.5,1,1.5) of the Fe₂P type,with comprehensive characterizations on crystal structure,electronic structure and magnetic properties.According to synchrotron powder X-ray diffraction data analysis and density functional theory calculation,Zr does not randomly but preferentially occupy during the doping process and results in weaker magnetic exchange interactions and ...     

Suppression of inner energy dissipation in Yb-doped NaErF4 upconversion nanocrystals through an energy cycling strategy

Suppression of the inner energy dissipation,related to the lattice phonons and inner defects,in lanthanide doped upco nversion luminescent materials remains a formidable challenge.Herein,we reveal an energy cycling strategy capable of suppressing the inner energy dissipation in lanthanide doped upconversion nanocrystals.Yb³⁺ ions were introduced in Er³⁺ heavily doped nanocrystals as an energy reservoir to compete with the inner energy dissipation.The detailed energy cycling...