月桂醇聚氧乙烯醚(7)仲辛基磺基琥珀酸混合双酯钠的合成与性能

采用控制酯化率和非外加相转移催化剂的方法,在敞开体系中合成了月桂醇聚氧乙烯醚(7)仲辛基磺基琥珀酸混合双酯钠。最佳工艺条件为:n[月桂醇聚氧乙烯醚(7)]:n(马来酸酐)=1.00:1.10,于140℃单酯化反应2.5 h,得到单酯化率为99.8%的单酯化产物;n(仲辛醇):n(马来酸酐)=4.0:1.0,加热介质温度为220℃,双酯化反应3.5 h,得到双酯化率为94.96%的双酯化产物。n(亚硫酸氢钠):n(马来酸酐)=1.10: 1.00,加热介质温度为190℃,磺化反应4.5 h,产物的表面张力为30.9 mN/m、临界胶束浓度为1.26×10~(-4) mol/L、乳化力为4.46 min、渗透力为3.35 s、分散力为91.85%、去油污力为98.93%。与磺基琥珀酸二辛酯钠盐(快T)和月桂醇聚氧乙烯醚(7)磺基琥珀酸单酯二钠盐(LESS)进行性能对比,产物分散力、去油污性能较快T均得到了改善;与LESS相比,渗透性能得到了较大的提高。     

杯[4]芳烃烷基醚磺酸钠的合成与表面性能

以对叔丁基苯酚、甲醛、苯酚、无水三氯化铝、浓硫酸、正溴代烷等为原料,经缩聚、脱烷基化、磺化和醚化反应,合成了一系列水溶性杯[4]芳烃烷基醚磺酸钠(烷基分别为—C4H9,—C6H13,—C8H17,—C10H21,化合物依次命名为1-C4,1-C6,1-C8,1-C10)。借用傅里叶变换红外光谱仪,表征了中间体和最终试样结构。用染料法对试样进行了表征,表明试样均为负离子表面活性剂。用滴体积法测定表面活性剂水溶液25℃时的表面张力,各试样分别能将水的表面张力降至32.06,34.96,42.35,45.35 mN/m;临界胶束浓度分别为1.26×10-3,0.32×10-3,1.78×10-3,1.20×10-3mol/L。     

Activation of Oxygen‐Stabilized Sulfur for Li and Na Batteries

The sulfur‐based cathode materials suffer severely from poor cycling stability and low utilization, incurred by their stepwise reaction mechanism that generates polysulfide intermediates and the subsequent irreversible losses. In this work, those issues are significantly relieved by entrapping sulfur species in carbon host rich in oxygen functionalities. Sulfur species in such C/S composite are highly stabilized by their interaction with oxygen, and can deliver a reversible capacity of 508 mAh/(g of S) for 2000 cycles when coupled with Li, representing the best cycling stability up to date. More interestingly, extra capacity can be accessed by simply prelithiating the oxygen‐stabilized C/S composites down to 0.6 V for a few cycles, which enables a high capacity of 1621 mAh/(g of S) that eventually stabilizes at 820 mAh/(g of S) for 600 cycles. The mechanism for this electrochemical activation process is investigated with both spectroscopic and electrochemical techniques, which reveal that the inactive sulfur bonded to oxygen is liberated in the initial deep lithiation precycles and becomes electrochemically active. The oxygen‐stabilized sulfur can also be coupled with Na anode to form Na/S cell, confirming that the formation of S?O interaction in C/S composite generates promising sulfur‐based cathode materials for Li–S and Na–S batteries.     

Structural Aspects of P2-Type Na0.67Mn0.6Ni0.2Li0.2O2 (MNL) Stabilization by Lithium Defects as a Cathode Material for Sodium-Ion Batteries

A known strategy for improving the properties of layered oxide electrodes in sodium-ion batteries is the partial substitution of transition metals by Li. Herein, the role of Li as a defect and its impact on sodium storage in P2-Na_0.67Mn_0.6Ni_0.2Li_0.2O₂ is discussed. In tandem with electrochemical studies, the electronic and atomic structure are studied using solid-state NMR, operando XRD, and density functional theory (DFT). For the as-synthesized material, Li is located in comparable amounts within the sodium and the transition metal oxide (TMO) layers. Desodiation leads to a redistribution of Li ions within the crystal lattice. During charging, Li ions from the Na layer first migrate to the TMO layer before reversing their course at low Na contents. There is little change in the lattice parameters during charging/discharging, indicating stabilization of the P2 structure. This leads to a solid-solution type storage mechanism (sloping voltage profile) and hence excellent cycle life with a capacity of 110 mAh g^-1 after 100 cycles. In contrast, the Li-free compositions Na_0.67Mn_0.6Ni_0.4O₂ and Na_0.67Mn_0.8Ni_0.2O₂ show phase transitions and a stair-case voltage profile. The capacity is found to originate from mainly Ni³⁺/Ni⁴⁺ and O^2-/O^2-δ redox processes by DFT, although a small contribution from Mn⁴⁺/Mn⁵⁺ to the capacity cannot be excluded.     

双轴晶体和频产生589nm钠黄光的相位匹配特性

讨论了利用双轴晶体KTP与LBO对1064nm与1319nm激光进行和频产生589nm钠黄光的和频相位匹配特性。推导得出对于和频情况下的非线性极化张量的表达式,并应用于倍频情况进行了验证。进行了和频相位匹配的理论分析,给出了这两种晶体在和频时的最佳相位匹配角和有效和频系数。     

FeO0.7F1.3/C Nanocomposite as a High‐Capacity Cathode Material for Sodium‐Ion Batteries

Searching high capacity cathode materials is one of the most important fields of the research and development of sodium‐ion batteries (SIBs). Here, we report a FeO_0.7F_1.3/C nanocomposite synthesized via a solution process as a new cathode material for SIBs. This material exhibits a high initial discharge capacity of 496 mAh g^?1 in a sodium cell at 50 °C. From the 3^rd to 50^th cycle, the capacity fading is only 0.14% per cycle (from 388 mAh g^?1 at 3^rd the cycle to 360 mAh g^?1 at the 50^th cycle), demonstrating superior cyclability. A high energy density of 650 Wh kg^?1 is obtained at the material level. The reaction mechanism studies of FeO_0.7F_1.3/C with sodium show a hybridized mechanism of both intercalation and conversion reaction.     

含钒云母矿的钠化焙烧工艺及机理探讨

本文对含钒云母中五氧化钒的焙烧工艺进行了详细研究 ,并结合实验结果进行了钠化焙烧机理的探讨 ,特别是氧气与氯气在焙烧中的作用以及氧化气氛与氯化气氛的关系。     

多环芳烃污染土壤的化学氧化处理研究

以国内某焦化企业场地多环芳烃污染土壤为研究对象，研究了过硫酸钠作为氧化剂时，硫酸亚铁或次氯酸钠助剂的使用对修复效率的影响，同时通过对比阐述了硫酸亚铁及次氯酸钠在过硫酸钠氧化体系中的不同作用。结果表明：微量硫酸亚铁对过硫酸钠氧化土壤中多环芳烃起到催化作用，可显著提高多环芳烃去除效率；次氯酸钠可与过硫酸钠协同使用，达到共氧化的目的。     

Properties of aqueous solutions for two binary mixed systems between two kinds of bile salts and nonionic surfactants

The micellar properties of aqueous binary mixed solutions for two systems consisting of sodium cholate (NaC)-octaoxyethylene glycol mono n-decyl ether (C₁₀E₈) and sodium glycocholate (NaGC)-C₁₀E₈ have been studied on the basis of surface tensions, polarity of the micelle interior and the mean aggregation number. Application of two theoretical treatments, based on regular solution and excess thermodynamic quantities for critical micellar concentration (CMC) data from surface tension curves of two mixed systems showed that the mole fraction of each bile salt in the mixed micelles near the CMC is lower than that of the corresponding prepared mole fraction in the mixed solution. The polarity of the interior suggested that the hydrophobicity of intramicelles increased with the increase of the mole fraction of bile salt in the mixed solution and that the mixed micelles become dramatically more hydrophobic at a mole fraction of 0.68 for NaGC−C₁₀E₈ system and 0.75 for NaC−C₁₀E₈ system, respectively. This implies that the micelles become richer in the bile salt molecules and the tendency appears strongly for NaGC−C₁₀E₈ system due to the strong cohesion between the conjugated glycines in the NaGC molecules. The decrease of aggregation number with the increase of the mole fraction of bile salts shows that the micelles approach those of the single system of each bile salt. This supports the previously mentioned facts.