Adaptive Boolean Logic Using Ferroelectrics Capacitors as Basic Units of Artificial Neurons and Its Implementation in FPGA

In this work we propose the implementation of boolean logic through artificial neurons with Ferroelectric Capacitor (FeCapacitor) as its basic unit on a reconfigurable hardware platform. Two neurons were implemented: the Perceptron and the Spiking Neuron model. Both neurons use the phenomenon of the hysteresis loop as an activation function and were embedded on a Field Gate Programmable Gate Array (FPGA) hardware platform. The implementations were carried out by Simulink models and hardware synthesizable blocks from DSP Builder software and the results are shown in the form of the models and the boolean functions implemented by them.     

Microstructure evolution during the co-sintering of Ni/BaTiO3 multilayer ceramic capacitors modeled by discrete element simulations

Electrode discontinuities are a critical issue for manufacturing ultrathin multilayer ceramic capacitors (MLCCs). The Discrete Element Method is used to simulate, at the particle length scale, the microstructure evolution during the co-sintering of state-of-the-art nickel based-MLCCs. Electrode discontinuities are considered to originate from the heterogeneities in the initial powder packing and to grow because of the constraint imposed by adjacent dielectric layers. A parametric study demonstrates that: (i) fast heating rate leads to lower electrode discontinuity during heating, (ii) green density and thickness of the electrode should be optimized to improve the electrode connectivity, (iii) rearrangement of the nickel particles plays a significant role in electrode discontinuity, and (iv) the addition of non-sintering inclusions can improve the electrode connectivity. These findings can be generalized to other multilayer components.     

矩阵变换器真的不需要贮能元件吗?

矩阵变换器MC有许多突出的优点,但它不像许多文献中介绍的那样是“纯硅变频器”,MC和交直交电压型变频器VSI一样,也需要贮能元件,输入滤波电容和过电压钳位电容就是MC的贮能元件。前者解决MC变换电路输入电流波形跳变问题,后者吸收过流保护动作时负载电感中贮存的磁场能量和实现动能缓冲。二者的区别在于:VSI的贮能电容集中装于一处,而MC分装于两处。还讨论了电容的选择原则。     

树状配电线路并联电容器无功优化规划

为解决含分支树状配电线路无功补偿问题,提出了在树状配电线路安装多台固定容量电容器的无功优化规划方法。该方法以净节约金额最大为目标函数,采用等效负荷法将树状配电线路转化为多个梳状配电线路,分别对各个等效线路进行优化规划,将目标函数值最大者对应的方案确定为最优规划方案。实例分析和规划结果验证了该方法的正确性和可行性。     

氧化改性Ni(OH)2的电化学电容特性研究

为获得高比电容量电极材料,制备出氧化改性Ni(OH)2,并对样品进行了XRD和XPS分析,通过恒流充放电测试分析了氧化改性Ni(OH)2/活性炭非对称型电化学电容器的电容特性,讨论了活性炭与氧化改性Ni(OH)2质量比对比电容量的影响。结果表明,氧化改性Ni(OH)2电容器性能稳定,稳定工作电压可达1.60V;在活性炭与氧化改性Ni(OH)2质量比约为2.7时,比电容量高达93.78F/g。     

箔式聚丙烯电容器电压失效机理及工艺控制

箔式聚丙烯电容器在高温负荷及整机使用时易击穿。为了改善箔式电容器的抗电性能,对切割、卷绕、热压、焊接和浸渍工艺进行了研究。结果表明:切割时应尽量消除铝箔毛刺,卷绕时毛刺应卷在芯子端面,热压压强取5.88MPa,焊接时控制引线间距,浸渍应在真空度为–0.09MPa时进行。     

Review of recent advances of polymer based dielectrics for high-energy storage in electronic power devices from the perspective of target applications

Polymer-based dielectric capacitors are widely-used energy storage devices.However,although the functions of dielectrics in applications like high-voltage direct current transmission projects,distributed energy systems,high-power pulse systems and new energy electric vehicles are similar,their requirements can be quite different.Low electric loss is a critical prerequisite for capacitors for electric grids,while high-temperature stability is an essential pre-requirement for those in electric vehicles.This paper reviews recent advances in this area,and categorizes dielectrics in terms of their foremost properties related to their target applications.Requirements for polymer-based dielectrics in various power electronic equipment are emphasized,including high energy storage density,low dissipation,high working temperature and fast-response time.This paper considers innovations including chemical structure modification,composite fabrication and structure re-design,and the enhancements to material performances achieved.The advantages and limitations of these methods are also discussed.     

Cathodic deposition and characterization of tin oxide coatings on graphite for electrochemical supercapacitors

Amorphous tin oxide (SnO_x) was cathodically deposited onto graphite electrode in a bath containing 0.1 M stannous chloride (SnCl₂), 0.5 M sodium nitrate (NaNO₃), and 0.4 M nitric acid (HNO₃) in an aqueous solution of 50% (v/v) ethanol. The SnO_x coatings grown on graphite were characterized as typical capacitive behaviors by cyclic voltammetry (CV), chronopotentiometric (CP) in 0.5 M KCl. Specific capacitance (in milli-farad per square centimeter, C_a) changes linearly with the deposition charge up to 4.5 C cm⁻², and a maximum of as high as 355 mF cm⁻² was obtained with the SnO_x coating grown at around 5 C cm⁻². For the SnO_x coating deposited at 0.2 C cm⁻², a maximum specific capacitance (in farad per gram, C_m) of 298 and 125 F g⁻¹ was achieved from CVs at a scan rate of 10, and 200 mV s⁻¹, respectively. The value of C_m significantly gets lower from 265 to around 95 F g⁻¹ when the deposition charge increases from 0.2 to around 6.0 C cm⁻². The long cycle-life and stability of the SnO_x coatings on graphite via the presented cathodic deposition were also demonstrated.     

BaTiO3基多层陶瓷电容器抗还原介质材料的研究进展

多层陶瓷电容器(MLCC)是一类重要的片式元器件,内电极的贱金属化已成为其产品开发的主流。MLCC内电极贱金属化的关键技术是获得抗还原性能优异的瓷料,能够与贱金属镍电极实现共烧的BaTiO3基抗还原瓷料的研究是目前MLCC研究的热点。本文综述了BaTiO3基抗还原介质材料的抗还原机理、制备方法及研究进展。     

中国科学院成功研制出氧化钛“光开关”材料

采用循环伏安电沉积技术在钛基上获得水合氧化钌(RuOx·nH2O),其比容量为105F/g。通过电化学测试(循环伏安、恒电流充放电)、X射线衍射(XRD)、扫描电镜(SEM)以及X射线光电子能谱(XPS)等方法研究了沉积物的电化学性质、物相及组成。结果表明:电沉积法获得的水合氧化钌呈非晶态结构,它由多氧化态钌混合羟基氧化物组成。在1.0mol·L-1H2SO4溶液中,该氧化物呈准电容特征,有较高电化学可逆性,可用作电化学电容器电极材料。