High-resolution FIB-TEM-STEM structural characterization of grain boundaries in the high dielectric constant perovskite CaCu3Ti4O12

In this work, the grain boundaries composition of the polycrystalline CaCu₃Ti₄O₁₂ (CCTO) was investigated. A Focused Ion Beam (FIB)/lift-out technique was used to prepare site-specific thin samples of the grain boundaries interface of CCTO ceramics. Scanning transmission electron microscopy (STEM) coupled with energy dispersive X-ray spectrometry (EDXS) and Electron Energy Loss Spectroscopy (EELS) systems were used to characterize the composition and nanostructure of the grain and grain boundaries region. It is known that during conventional sintering, discontinuous grain growth occurs and a Cu-rich phase appears at grain boundaries. This Cu-rich phase may affect the final dielectric properties of CCTO but its structure and chemical composition remained unknown. For the first time, this high-resolution FIB-TEM-STEM study of CCTO interfacial region highlights the composition of the phases segregated at grain boundaries namely CuO, Cu₂O and the metastable phase Cu₃TiO_4.     

基于加密编码矢量的农业无线传感网数据安全存储方法

无线传感网为精准农业生产环境监测提供了一种有效的解决方案。针对当前农业生产中无线传感网感知数据传输和存储过程中存在的安全性不高、存储效率不佳的问题,在研究农业无线传感网主要特征的基础上,分析了云存储技术对农业传感器感知数据存储的有效性,利用改进的网络编码技术降低了传感器感知数据在传输汇聚时对无线网有限带宽的占用率,给出了基于加密编码矢量方法的农业无线传感网感知数据传输、存取安全性和效率分析,提出了一种基于加密编码矢量的农业无线传感网感知数据信息的安全存储新方法。大田生产环境测试结果表明,基于网络编码的加密编码矢量方法安全性较高,在数据量显著增加的情况下传输性能可进一步得到提升,从而验证了本方法的合理性和实用性。     

交互式理念在包装设计中的应用分析

目的研究交互式理念在现代包装设计中的具体应用。方法以人体工程学、艺术设计学为研究基础,采用系统分析法、案例分析法等论证方法,阐述如何运用交互式理念来满足消费者对包装的情感需求。结论交互式理念在包装结构、视觉元素以及包装材料方面的应用,创新了现代包装设计,赋予了其独特的视觉形象和贴切的人文关怀。     

基于GSM短信的抽油机自动检测及报警系统的设计

介绍了单片机控制的GSM无线短信TC35I模块在抽油机检测和故障报警中的应用,该系统可以实时监控抽油机工作状态,并能进行自动报警,具有较强的实用性。     

浅谈市场经济环境下的个人信息保护

分析了市场经济环境下个人信息权被侵害现状,介绍了目前国家对公民个人信息权的法律保护情况,同时阐述了公民个人信息权保护的意义。     

Macaroon-like FeCo2O4 modified activated carbon anode for enhancing power generation in direct glucose fuel cell

Macaroon-like FeCo₂O₄ nanomaterial was prepared and used as electrocatalyst in direct glucose alkaline fuel cell (DGAFC), which exhibited high catalytic activity towards glucose oxidation reaction. Maximum power density of 35.91 W m⁻² was achieved in the DGAFC equipped with a FeCo₂O₄ modified activated carbon (AC) anode, which was almost 151% higher than the control. Physical and electrochemical characterizations were performed to provide further understanding of the origin of its high activity. Our results show that the introduction of FeCo₂O₄ into the AC anode remarkably increase the exchange current density and reduce the charge transfer resistance. It is supposed that there is a synergistic effect between Fe (III) and Co (III), which accelerates electron transfer from glucose to external circuits. This study will promote the development of cost effective and environmentally benign catalysts for electrochemical energy applications.     

On the formation mechanisms of fine granular area (FGA) on the fracture surface for high strength steels in the VHCF regime

The fine granular area (FGA) plays a crucial role in the VHCF regime. However, so far, the uniform understanding or conclusion about the formation mechanism of FGA has not been drawn. In view of the significance of FGA, the current studies on FGA, i.e., the FGA size, the stress intensity factor range at the periphery of FGA, the crack initiation and growth process in FGA, and the formation mechanisms of FGA, are reviewed in the present paper. The role of internal hydrogen in the VHCF regime is further discussed. In the end, two important definite conclusions are drawn based on the present investigations.     

内存升级带来问题的研究

逻辑Bank主要是内存内部数据存取阵列,而物理Bank则是内存和处理器之间交换数据的通道。要弄清这些升级带来的问题,首先要弄清内存的结构和工作原理。     

虚拟网络分析仪在射频电路设计中的应用

射频电路的设计有很多困难,电路性能需要综合考虑和优化,需要反复调整电路结构,现有的仿真方式不能满足全部要求。以射频LNA电路的设计为例,使用Multisim的虚拟网络分析仪进行仿真设计,包含电路结构、电路稳定性和匹配网路设计,实际测量结果证明仿真准确度很高。实践表明,使用虚拟网络分析仪进行RF电路设计,可以降低实验成本,缩短设计周期,虚拟网络分析仪在射频电路的教学、实验和研发中,起着越来越重要的作用。     

十二烷基硫酸钠修饰NiFe2O4对亚甲基蓝的类芬顿催化氧化性能

采用化学沉淀法制备了十二烷基硫酸钠（SDS）改性的纳米酸镍（记为NiFe₂O₄-S）,利用X射线衍射（XRD）、红外光谱（FTIR）、能谱（EDS）、透射电镜（TEM）、BET比表面等技术手段对样品进行了表征。采用多相芬顿氧化技术,以亚甲基蓝溶液为模拟污染物废水,研究了SDS对铁酸镍的改性效果、亚甲基蓝溶液初始pH以及催化剂循环使用等不同条件因素对样品类芬顿催化活性的影响。结果显示,经SDS改性后的NiFe₂O₄-S比纯相NiFe₂O₄表现出了更优异的催化性能,NiFe₂O₄-S对酸性（pH=3.5）、近中性（pH=6.5）和碱性（pH=9.5）的亚甲基蓝溶液均有着较好的催化降解效果;NiFe₂O₄-S具有良好的催化稳定性和重复使用性。对该催化反应体系的作用机理进行了详细探讨,NiFe₂O₄-S表现出优异的类芬顿催化活性归因于更强的电子转移能力,吸附的SDS能促进H₂O₂和 \text{?} {\mathrm{O}}_{\mathrm{2}}^{\text{-}} 分别与表面Fe³⁺反应将其还原转化为Fe²⁺。·OH是直接分解亚甲基蓝的活性物种,反应中NiFe₂O₄-S表面较高浓度的Fe²⁺可以有效地把H₂O₂分解为·OH。SDS增强了催化剂表面对亚甲基蓝的吸附能力,促进了·OH与亚甲基蓝的分解反应。