碳酸钠浓度对废电池铅膏脱硫影响机制与动力学

以铅膏为研究对象，采用碳酸钠为脱硫剂，系统研究了碳酸钠浓度对铅膏脱硫率及铅收得率的影响，并借助化学分析、扫描电镜分析仪（SEM-EDS）、X射线衍射分析仪（XRD）揭示了铅膏脱硫反应机理，计算了动力学参数。结果表明，铅膏脱硫率随碳酸钠浓度的增加而增大，而铅收得率变化规律相反。铅膏主要由硫酸铅及铅的氧化物组成。在碳酸钠浓度小于0.150 mol/L时，脱硫产物中主要以PbCO₃和Pb₃（CO₃）₂（OH）₂形式存在；随着浓度的增加，PbCO₃不断向Pb₃（CO₃）₂（OH）₂转化，并最终转化为NaPb₂（CO₃）₂（OH）₂，导致铅收得率降低。铅膏脱硫过程活化能随浓度的增大而减小，受化学反应控制。浓度低于0.208 mol/L时，活化能降低幅度较大，由7.275 kJ/mol降至5.312 kJ/mol，之后活化能随浓度的增加变化程度较小。     

Electrical Characterization of Individual Cesium Lead Halide Perovskite Nanowires Using Conductive AFM

Perovskite nanostructures have attracted much attention in recent years due to their suitability for a variety of applications such as photovoltaics, light-emitting diodes (LEDs), nanometer-size lasing, and more. These uses rely on the conductive properties of these nanostructures. However, electrical characterization of individual, thin perovskite nanowires has not yet been reported. Here, conductive atomic force microscopy characterization of individual cesium lead halide nanowires is presented. Clear differences are observed in the conductivity of nanowires containing only bromide and nanowires containing a mixture of bromide and iodide. The differences are attributed to a higher density of crystalline defects, deeper trap states, and higher inherent conductivity for nanowires with mixed bromide–iodide content.     

白厚漆中挥发性有机物的吹扫捕集/气相色谱-质谱分析方法研究

采用吹扫捕集/气相色谱-质谱法(PT/GC-MS)建立了白厚漆中挥发性有机物的快速分析方法。在优化吹扫捕集和气相色谱-质谱参数的基础上,在白厚漆中共鉴别出34个挥发性有机物成分。该方法简便、快捷、灵敏,适用于白厚漆中挥发性有机物的分析,并为白厚漆对水质和环境的影响研究提供理论依据。     

含铅固废协同冶炼过程PbO-CaO-SiO2-Fe2O3-ZnO五元渣系相平衡研究

在1 000~1 250 ℃范围内,采用高温平衡-淬冷-EDS方法研究了含铅固废协同冶炼过程PbO-CaO-SiO₂-Fe₂O₃-ZnO五元渣系在空气气氛下的相平衡规律。研究结果表明,渣中存在的主要物相有尖晶石(Zn_xFe_3-yO_4+z)、红锌矿(ZnO)、黄长石(Pb_vCa_2-vZn_wSi₂O₇)、赤铁矿(Fe₂O₃)、磁铁铅矿(PbFe₁₀O₁₆)和硅钙石(Ca_2-tPb_tSiO₄)。在1 250 ℃、1 200 ℃、1 170 ℃、1 130 ℃和1 100 ℃下,PbO-CaO-SiO₂-Fe₂O₃-ZnO体系的液相点分布测试结果与MTDATA6.0软件模拟液相线基本吻合。在1 000~1 250 ℃范围内,随着结晶过程的进行,PbO-CaO-SiO₂-Fe₂O₃-ZnO体系液相成分中Fe₂O₃含量从16.83%减少到7.67%,ZnO含量从7.62%减少到2.98%,(PbO+CaO+SiO₂)含量从75.55%增加到89.36%。     

基体稀释或基体匹配石墨炉原子吸收光谱法测定土壤样品中铅和镉

用石墨炉原子吸收光谱法测定土壤样品中Pb和Cd时,有时候直接按照方法标准GB/T 17141—1997操作,测定结果不能满足质控要求。研究结果表明,目标元素系列标准溶液中,分别含和不含土壤基体元素Na、Mg、Al、Si、Fe、Ca等元素混合成分时,校准曲线斜率明显不同。为减小基体效应的影响,基于文献调研和实验结果,对上述方法标准实验步骤进行了下列改进:(1)取相同体积实际样品消解液混合后,定量加入到用于建立校准曲线的系列标准溶液中,用于基体匹配;(2)对消解液进行适度稀释,仍采用标准溶液建立校准曲线。用4个土壤标样和土壤样品加标测定结果对改进后的方法进行了验证,结果表明,基体稀释法测定Pb的回收率范围分别为90.4%~114%;测定低含量Cd时,回收率范围为84.1%~125%。基体匹配法测定Pb和Cd的回收率范围分别为93.0%~105%和102%~119%,基本满足土壤样品中重金属回收率为80%~120%的质控要求。样品中痕量镉在测定下限附近时,应严格控制稀释倍数,或采用基体匹配法测定。改进后的操作步骤适合日常检测工作中大批量土壤样品中Pb和Cd的准确测定。     

Enhancement of energy storage density in antiferroelectric PbZrO3 films via the incorporation of gold nanoparticles

In this work, antiferroelectric Au–PbZrO₃ (Au–PZO) nanocomposite thin films were prepared by chemical solution deposition (CSD), and the effects of Au concentration on the antiferroelectric properties and the recoverable energy density were investigated. The results showed that the optimal Au concentration in the Au–PZO nanocomposite thin films was about 1 mol% for structural and electric properties. In the Au–PZO nanocomposite thin films with 1 mol% Au, Au nanoparticles (NPs) were distributed uniformly in the perovskite PZO matrix. Moreover, the recoverable energy density was 10.8 J/cm³ at 600 kV/cm, which is 42% higher than that of the pure PZO films. The results demonstrate that adding an appropriate amount of noble metal NPs in antiferroelectric thin films is an effective method to improve the energy storage properties.     

Price and lead time differentiation,capacity strategy and market competition

We study a duopoly market in which customers are heterogeneous, and can be segmented as price or time sensitive. Each firm tailors (differentiates) its products/services for the two customer classes solely based on guaranteed lead time and the corresponding price. Our objective is to understand how competition affects price and lead time differentiation of the firms in the presence of different operations strategy (shared versus dedicated capacity), product substitution and asymmetry between the competing firms. Our results suggest that when firms use dedicated resources to serve the two market segments, pure price competition always tends to decrease individual prices as well as price differentiation, irrespective of the market behaviour. Further, the effect of competition is more pronounced when customers are allowed to self-select, thereby introducing substitutability between the two product options. On the other hand, when firms compete in time, in addition to price, the effect of competition on product differentiation depends crucially on the behaviour of the market. Our results further suggest that the firm with a larger market base should always maintain a larger price and lead time differentiation between the two market segments. Similarly, the firm with a capacity cost advantage should also maintain a larger lead time differentiation.