Sharpening polycrystalline phase boundary for potassium sodium niobate ceramics with MnF2 modification

The influence of anion on structure and performance is unclear in potassium sodium niobate ((K,Na)NbO₃; KNN)-based ceramics, while cation doping has been widely researched. Here, the phase structure and electrical properties are explored in MnF₂-doped KNN ceramics. Significantly, sharp rhombohedral–orthorhombic (R–O) and orthorhombic–tetragonal (O–T) phase boundary as well as reduced diffusion degree is exhibited in the ceramics along with little changed phase transition temperatures due to the optimized F⁻ content at O site, which is different from that of cation replacement for A and B sites. Notably, the domain wall motion is facilitated due to the increased A vacancy and decreased O vacancy along with strengthened polarity, originating from the higher valence state and electronegativity of F⁻ with respect to O²⁻. And then, enhanced ferroelectricity is realized via MnF₂ modification, the piezoelectricity is elevated in turn. This work presents a new idea of anion doping for controlling structure and properties in perovskite materials.     

Application of Mathematical Modeling in Technology for the Recovery of Rubber from Latex in a Magnetic Field

Theoretical Foundations of Chemical Engineering - The paper presents a study of the process of the isolation of styrene-butadiene rubber from latex with the method of mathematical planning for a...     

第四媒体中眨动的眼睛-对网络广告新艺术形式的探索

第四媒体——网络的出现,在21世纪的人类文明进程中产生无可比拟的作用。它的信息资源无限丰富,图文互动和高效高速的特点,对印刷、广播、电视三大媒体带来了巨大的冲击。人们每天都不断地在互联网上收集、查询和发布各种各样的信息,这样的信息发布与传播方式无疑给广告提供了一个展示的平台。     

导弹综合试验与评估方法研究

科学合理的导弹试验与评估方法能够有效缩短研制周期,提高试验效益。导弹综合试验与评估方法旨在总体规划和设计导弹试验过程和内容,依据导弹模型验证技术提高建模与仿真在导弹试验与评估中的地位和作用,采用多源信息融合技术和Bayes评估技术提高导弹试验与评估结果的可信性。详细阐述了基于ST&E的导弹试验设计方法,并就综合试验设计的关键问题提出解决思路和方法。     

A Decomposition Route for Synthesis of Al2O3 Crystal and its Applications as Thermal Conductivity Filler

Platelike α‐Al₂O₃ powder was obtained at 850°C by thermal decomposition of ammonium aluminum carbonate hydroxide precursor, which was treated by hydrofluoric acid. The results showed the decomposition of the as‐prepared precursors experienced via three steps, adsorption of physical water, dehydration of crystalline water, and decomposition of the precursor, and the activation energies of the above three steps were calculated using the Coats–Redfern method. Meanwhile, the intermediate of (NH₄)₃AlF₆ obtained played an important role in decreasing activation energy of the decomposition and phase transformation. Moreover, the thermal conductivity of the epoxy resin filled with platelike alumina was improved obviously.     

The use of environmental scanning electron microscopy for imaging the microstructure of gels for profile control and water shutoff treatments

The use of gel systems as profile control and water shutoff agents has become a wide practice in recent years for oil recovery applications. But few systematic studies have been carried out on the microstructure of gels. In this study, environmental scanning electron microscopy (ESEM) was employed to investigate the microstructure of gels in their natural state. It was directly observed that a three‐dimensional network structure formed in chromium or zirconium crosslinked polymer gels is the same as organic/ inorganic crosslinked gels. However, there is a dense flat structure in phenol resin crosslinked polymer gels or phenolic resin gels. The differences between the microstructures can be attributed to the different crosslinking sites and crosslinking density, and this affect the gel's stability at reservoir temperatures. In addition, this paper also introduced the crosslinking mechanism and macro‐morphology of the bulk gels. It can contribute to a better understanding of the gel's microstructure. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39946.     

Tuning of dielectric and ferroelectric properties in single phase BiFeO3 ceramics with controlled Fe/Fe ratio

Single phase multiferroic BiFeO₃ (BFO) ceramics were synthesized with controllable amount of Fe²⁺ and oxygen vacancies in a very wide concentration range. Double ferroelectric hysteresis loops are observed in fresh BFO ceramics at room temperature without any aging processes. Detailed study shows that this is due to the defect dipoles which have preferential orientations antiparallel to the direction of spontaneous polarization, providing a driving force for domain back-switching. The dielectric constant of BFO could be enormously enhanced by 100 times by increasing the Fe²⁺ content, employing a polaronic relaxation process.     

聚合釜搅拌电机损坏原因分析

总结了PVC聚合釜电机频繁损坏原因及单相接地故障的危害。通过实施改造措施,降低了聚合釜电机损坏率,保证了聚合釜及电力系统的安全稳定运行。     

埃索美拉唑钠的波谱学数据和结构确证

建立利用分析仪器确证埃索美拉唑钠化学结构的方法。利用UV、IR、NMR、MS对埃索美拉唑钠进行了结构分析。对埃索美拉唑钠的红外吸收光谱(IR)、核磁共振氢谱(1H NMR)、氢-氢相关谱(1H-1H COSY)、核磁共振碳谱13C NMR、DEPT谱、碳氢相关谱(HMQC)、碳氢远程相关谱(HMBC)及质谱(MS)进行了解析,对其所有的NMR谱信号进行了归属;讨论了红外光谱特征吸收峰所对应的官能团的振动形式,确证了埃索美拉唑钠的结构为S-5-甲氧基-2-{[(4-甲氧基-3,5-二甲基-2-吡啶基)甲基]亚磺酰基}-1H-苯并咪唑钠。本研究为埃索美拉唑钠的结构鉴定提供了依据。