四苯硼钠比浊界限分析法测钾

试样经掩蔽铁杂质后,在微酸性条件下用四苯硼钠沉淀钾离子再与钾标准进行比浊,该方法便捷,测定范围为≥0．4≤1．2g／1KClO3。     

液相法合成氢化铝钠的研究

以NaH和AlCl3为主要原料,通过改变实验条件,探索研究液相法合成NaAlH4的合成条件。实验表明,在不加入任何催化剂的情况下无法实现NaAlH4的合成,在以NaAlH4、三乙基铝等物质为催化剂的条件下,虽有少量的产物生成,但是反应不明显,且产物中存在大量的非晶态物质。即便在高温高压下反应亦难以进行,大量的化合物均以非晶态形式存在。     

The impact of alkali elements on the degradation of CIGS solar cells

Unencapsulated CIGS solar cells with high and low contents of sodium (Na) and potassium (K) were simultaneously exposed to damp heat and illumination. The solar cells with a high alkali (Na, K) content exhibited higher initial conversion efficiencies, but degraded severely within 100 h, while the alkali poor samples kept relatively stable performance under damp heat and illumination. The degradation of the samples with a high alkali content resulted in the formation of sodium rich spots on the top ZnO:Al surface of the samples. This is likely caused by light‐induced Na⁺ migration via the grain boundaries in the absorber to the depletion region, where the Na⁺ accumulated. This allowed subsequent Na⁺ transport through the depletion region due to the lowering of the internal electric field caused both by the Na⁺ accumulation and illumination. The migration resulted in the formation of shunt paths, which reduced the shunt resistance and open circuit voltage. Furthermore, ingression of water into the ZnO:Al is expected to be responsible for a slow but steady increase in series resistance for both high and low alkali solar cells. Additionally, sodium migration led to a severe increase of the series resistance in case of alkali rich samples. Copyright © 2015 John Wiley & Sons, Ltd.     

A Water Stable,Near‐Zero‐Strain O3‐Layered Titanium‐Based Anode for Long Cycle Sodium‐Ion Battery

Layered transition metal (TM) oxides of the stoichiometry Na_xMO₂ (M = TM) have shown great promise in sodium‐ion batteries (SIBs); however, they are extremely sensitive to moisture. To date, most reported titanium‐based layered anodes exhibit a P2‐type structure. In contrast, O3‐type compounds are rarely investigated and their synthesis is challenging due to their higher percentage of unstable Ti³⁺ than the P2 type. Here, a pure phase and highly crystalline O3‐type Na_0.73Li_0.36Ti_0.73O₂ with high performance is successfully proposed in SIBs. This material delivers a reversible capacity of 108 mAh g^?1 with a stable and safe potential of 0.75 V versus Na/Na⁺. In situ X‐ray diffraction reveals that this material does not undergo any phase transitions and exhibits a near‐zero volume change upon Na⁺ insertion/de‐insertion, which ensures exceptional long cycle life over 6000 cycles. Importantly, it is found that this O3‐Na_0.73Li_0.36Ti_0.73O₂ shows superior moisture stability, even when immersed into water, which are both elusive for conventional layered TM oxides in SIBs. It is believed that the small interlayer distance and high occupation of interlayer vacancy promise such unprecedented water stability.     

Boosting Piezo-Catalytic Activity of KNN-Based Materials with Phase Boundary and Defect Engineering

Although the piezo-catalysis is promising for the environmental remediation and biomedicine, the piezo-catalytic properties of various piezoelectric materials are limited by low carrier concentrations and mobility, and rapid electron-hole pair recombination, and reported regulating strategies are quite complex and difficult. Herein, a new and simple strategy, integrating phase boundary engineering and defect engineering, to boost the piezo-catalytic activity of potassium sodium niobate ((K, Na)NbO₃, KNN) based materials is innovatively proposed. Tur strategy is validated by exampling 0.96(K_0.48Na_0.52)Nb_0.955Sb_0.045O₃-0.04(Bi_xNa_4-3x)_0.5ZrO₃-0.3%Fe₂O₃ material having phase boundary engineering and conducted the defect engineering via the high-energy sand-grinding. A high reaction rate constant k of 92.49 × 10⁻³ min⁻¹ in the sand-grinding sample is obtained, which is 2.40 times than that of non-sand-grinding one and superior to those of other representative lead-free perovskite piezoelectric materials. Meanwhile, the sand-grinding sample has remarkable bactericidal properties against Escherichia coli and Staphylococcus aureus. Superior piezo-catalytic activities originate from the enhanced electron-hole pair separation and the increased carrier concentration. This study provides a novel method for improving the piezo-catalytic activities of lead-free piezoelectric materials and holds great promise for harnessing natural energy and disease treatment.     

Peering into Alloy Anodes for Sodium‐Ion Batteries: Current Trends,Challenges, and Opportunities

Sodium‐ion batteries (SIBs) are regarded as a complementary technology to lithium‐ion batteries (LIBs) in the effort of searching for alternative energy solutions that are cost‐effective and sustainable. The identification of suitable alternative anode materials is essential to close the gap in energy density between SIBs and LIBs. Solid‐state alloying reactions that work beyond intercalation mechanism are able to provide a significant improvement in specific capacity. This review describes key advances in SIBs with a primary emphasis on alloy anodes. Recent information and results published in the literatures are stressed to provide an overview of their development in SIBs. With the discussion of some of the remaining challenges and possible solutions, the authors hope to sketch out the scope for future studies in this field.     

Thickening Agents Effects on Sodium Binding and Other Taste Qualities of Soup Systems

Low sodium chicken broth with NaCl added to provide Na⁺ concentrations in typical reduced Na⁺ soups (144 and 288 mg Na⁺/240 mL serving) was thickened with commonly used gum, starch, or flour food additives. Xanthan gum suppressed saltiness as the result of ionic binding of Na⁺, as determined by sensory evaluation and ²³Na NMR spectroscopy. Saltiness was affected by added NaCl (p = 0.0001), thickener (p < 0.01), and added NaCl* thickener (p < 0.01), and positively correlated with chicken and overall flavors (p = 0.0001). Cornstarch provided body, no suppression of salt taste, and the greatest salt enhancement of chicken and overall flavors. In complex food systems, temperature and other factors affected Na⁺ binding as measured by NMR pointing to the need for a new model.     

硫酸铜浓度对微蚀速率的影响

详细分析了硫酸铜浓度对过硫酸钠体系微蚀速率的影响,并对其机理进行了探讨。     

改进的深度脱木素的硫酸盐蒸煮：第一部分 用硫化钠预处理的桉树硫酸盐蒸煮

用硫化钠水溶液预处理桉树，接着进行改进的深度脱木素硫酸盐蒸煮。结果表明，在１６０℃预处理后脱木素的选择性较常规硫酸盐蒸煮有显著提高，可得到低Ｋａｐｐａ值（约为１０）的浆而没有明显的强度损失。     

Creating an Air‐Stable Sulfur‐Doped Black Phosphorus‐TiO2 Composite as High‐Performance Anode Material for Sodium‐Ion Storage

With the increasing demand for low cost, long lifetime, high energy density storage systems, an extensive amount of effort has recently been focused on the development of sodium‐ion batteries (SIBs), and a variety of cathode materials have been discovered. However, looking for the most suitable anode material for practical application is a major challenge for SIBs. Herein, a high capacity sulfur‐doped black phosphorus‐TiO₂ (TiO₂‐BP‐S) anode material for SIBs is first synthesized by a feasible and large‐scale high‐energy ball‐milling approach, and its stability in air exposure is investigated through X‐ray photoelectron spectroscopy. The morphology of TiO₂‐BP‐S is characterized using transmission electron microscopy, indicating that the TiO₂ nanoparticles produce P? Ti bonds with BP. The TiO₂‐BP‐S composite with P? S and P? Ti bonds exhibits excellent stability in air and the superior electrochemical performance. For example, the discharge specific capacity is up to 490 mA h g^?1 after 100 cycles at 50 mA g^?1, and it remains at 290 mA h g^?1 after 600 cycles at 500 mA g^?1. Meanwhile, the scientific insight that the formation of stable P? S and P? Ti bonds can provide a guide for the practical large‐scale application of SIBs in other titanium base and black phosphorus materials is looked forward.