Development of Magnesium Anode-Based Transient Primary Batteries

Biodegradable primary batteries, also known as transient batteries, are essential to realize autonomous biodegradable electronic devices with high performance and advanced functionality. In this work, magnesium, copper, iron, and zinc – metals that exist as trace elements in the human body – were tested as materials for biomedical transient electronic devices. Different full cell combinations of Mg and X (where X = Cu, Fe, and Zn and the anodized form of the metals) with phosphate buffered saline (PBS) as electrolyte were studied. To form the cathodes, metal foils were anodized galvanostatically at a current density of 2.0 mA cm⁻² for 30 mins. Electrochemical measurements were then conducted for each electrode combination to evaluate full cell battery performance. Results showed that the Mg−Cu_anodized chemistry has the highest power density at 0.99 mW/cm². Nominal operating voltages of 1.26 V for the first 0.50 h and 0.63 V for the next 3.7 h were observed for Mg−Cu_anodized which was discharged at a current density of 0.70 mA cm⁻². Among the materials tested, Mg−Cu_anodized exhibited the best discharge performance with an average specific capacity of 2.94 mAh cm⁻², which is comparable to previous reports on transient batteries.     

Multiphase Flow Regime Characterization and Liquid Flow Measurement Using Low-Field Magnetic Resonance Imaging

Multiphase flow metering with operationally robust, low-cost real-time systems that provide accuracy across a broad range of produced volumes and fluid properties, is a requirement across a range of process industries, particularly those concerning petroleum. Especially the wide variety of multiphase flow profiles that can be encountered in the field provides challenges in terms of metering accuracy. Recently, low-field magnetic resonance (MR) measurement technology has been introduced as a feasible solution for the petroleum industry. In this work, we study two phase air-water horizontal flows using MR technology. We show that low-field MR technology applied to multiphase flow has the capability to measure the instantaneous liquid holdup and liquid flow velocity using a constant gradient low flip angle CPMG (LFA-CPMG) pulse sequence. LFA-CPMG allows representative sampling of the correlations between liquid holdup and liquid flow velocity, which allows multiphase flow profiles to be characterized. Flow measurements based on this method allow liquid flow rate determination with an accuracy that is independent of the multiphase flow profile observed in horizontal pipe flow for a wide dynamic range in terms of the average gas and liquid flow rates.     

Redox targeting of energy materials

The redox-mediated electrochemical–chemical process, when it involves the redox-targeting reaction with energy materials, has shown intriguing potential for various energy-related applications. This review starts with a brief discussion on the evolution of redox-targeting reactions for high-energy redox-flow batteries and the critical future studies for large-scale energy storage. Then, with spatially decoupled water electrolysis as an example, the merits of redox-targeting reaction by liberating the catalyst from electrode surface are highlighted, followed by an introduction of redox targeting–based thermal-to-electrical conversion. We have also featured various redox-targeting processes in other fields of study, such as electrochromic window, redox catalysis, and spent battery material recycling. Overall, this review attempts to demonstrate the incredible versatility and prospects of redox-targeting process for energy-related applications.     

阴极微弧电沉积制备Al2O3陶瓷层技术及研究进展

阴极微弧电沉积技术是一种在材料表面通过微弧放电沉积陶瓷层的表面处理技术,利用该技术可以在金属及非金属表面生成耐磨、耐蚀性能优异的陶瓷膜层.本文介绍了阴极微弧电沉积技术的研究现状以及应用阴极微弧电沉积技术制备Al2O3陶瓷层的方法和基本原理,并且对阴极微弧电沉积技术的影响因素进行了总结,阐述了阴极微弧电沉积技术的应用前景和存在的问题.     

还原氧化石墨烯修饰Bi2WO6提高其在可见光下的光催化性能

通过两步水热法合成了一种新型的还原氧化石墨烯(RGO)修饰的Bi₂WO₆(Bi₂WO₆-RGO), 结果表明其在可见光下的光催化性能得到了显著的提高. 研究了RGO在Bi₂WO₆-RGO中的含量对其光催化性能的影响, 从而确定出RGO相对于Bi₂WO₆的最佳掺杂质量比值为1%. 通过扫描电镜(SEM)研究发现, RGO并没有改变Bi₂WO₆光催化剂的结构和形貌. Bi₂WO₆-RGO在可见光下的光催化性能得以提高可以归功于RGO. 其可能的机理是石墨烯的存在有利于光生载流子(激子)的分离, 从而导致产生更多的O₂^·-用于有机染料污染物(如罗丹明B (RhB))的降解. RhB分子在石墨烯上的有效吸附可能也是导致Bi₂WO₆-RGO光催化性能提高的另一原因.     

光化学的初级过程和次级过程

针对物理化学教材中有关光化学初级过程和次级过程、初级过程的量子产率、初级过程的反应速率表示以及是否是零级反应等问题发表了看法。     

微波促进碱性离子液体催化合成查尔酮

以4-氯-1-丁醇,N-甲基咪唑和苯甲酸钠为原料,用微波法制得碱性离子液体{[OHBMIM]Ph COO(AIL)},其结构经FT-IR表征;以苯甲醛和苯乙酮为原料,AIL为催化剂,经微波促进的缩合反应合成了查尔酮(1),其结构经1H NMR和FT-IR确证。考察了AIL用量、微波功率、物料比和反应时间对1产率的影响。合成1的最佳反应条件为:AIL 1 mmol,苯甲醛5 mmol,n(苯甲醛)∶n(苯乙酮)=1.1,于微波功率140 W反应5 min,产率95.8%。AIL具有较好的循环使用性,循环使用6次,1产率没有明显降低。     

考尼伐坦关键中间体的合成

合成考尼伐坦关键中间体2-甲基-6-(4-甲基苯磺酰基)-1,4,5,6-四氢咪唑[4,5-d][1]苯并氮杂卓并对其工艺优化。以氨茴酸甲酯为起始原料,经保护、烃化、环合、脱羧、溴化、烃化并缩合共六步反应合成考尼伐坦关键中间体。所得的目标化合物经核磁共振氢谱、质谱确认,总收率达49.06%。该关键中间体合成方法和工艺改进后,所用原料价格便宜、反应条件温和、反应周期缩短、产率提高,更加适合于工业化生产。     

SAXS and WAXD study of periodical structure for polyacrylonitrile fiber during coagulation

Small angle X‐ray scattering (SAXS) and wide angle X‐ray diffraction (WAXD) were adopted to investigate the formation and development of high order structure within polyacrylonitrile (PAN) precursor during coagulation. The scattering signal came from the microvoids and long period structure was separated reasonably by the analog computation method of decomposition of the one‐dimensional profile. Based on the established methodology, the statistic parameters of long period structure, such as length of the long period structure, crystalline region and amorphous region, were obtained by the analysis of correlation function. The results indicated that during the coagulation, the length of long period of the nascent coagulated fiber was 56.1 nm (meridional direction) and 35.6 nm (equatorial direction), respectively. The evolution of the long period during the coagulation was also discussed by combining WAXD data. With the processing of coagulation, the long period was decreased since the crystallinity increased. Copyright © 2014 John Wiley & Sons, Ltd.     

O2‐mediated dehydrogenative amination of phenols

A method was developed for the direct dehydrogenative construction of C? N bonds between unprotected phenols and a series of cyclic anilines without resorting to any kind of metal activation of either substrate and without the use of halides. The resulting process relies on the exclusively organic activation of molecular oxygen and the subsequent oxidation of the aniline substrate. This allows the coupling of ubiquitous phenols, thus furnishing aminophenols through an atom‐economical and most sustainable dehydrogenative amination method. This new reactivity, which relies on the intrinsic organic reactivity of cumene in what can be seen as a modified Hock activation process of oxygen, is expected to have a large impact on the formation of C? N bonds in organic synthesis.