高效液相色谱-紫外法快速测定塑料类食品接触材料及制品中7种对苯二甲酸酯或苯甲酸酯的特定迁移量

建立了高效液相色谱-紫外检测（HPLC-UV）法快速测定从塑料类食品接触材料及制品迁移至10%（v/v）乙醇、3%（m/v,即3 g/100 mL）乙酸、4%（v/v）乙酸、20%（v/v）乙醇、50%（v/v）乙醇、95%（v/v）乙醇和橄榄油7种食品模拟物中对苯二甲酸二甲酯、对苯二甲酸二辛酯、苯甲酸甲酯、苯甲酸乙酯、苯甲酸丙酯、苯甲酸丁酯和新戊二醇二苯甲酸酯的特定迁移量。考察了多种提取溶剂、QuEChERS dSPE EMR-Lipid试剂盒和Captiva EMR-Lipid试剂盒对橄榄油食品模拟物中7种对苯二甲酸酯或苯甲酸酯的提取或净化效果。以甲醇和水为流动相进行梯度洗脱,7种对苯二甲酸酯或苯甲酸酯在苯基柱上于17 min内达到基线分离。检测波长为237 nm,进样量为10 μL。7种对苯二甲酸酯或苯甲酸酯在7种食品模拟物中的定量限为0.2~8.1 mg/kg、1~80 mg/L或8~160 mg/kg,相关系数r≥0.9998。在2或8、60、80或160 mg/kg 3个加标水平的回收率为91.7%~106%,相对标准偏差为0.1%~3.1%。该方法样品前处理简便,色谱分离和线性关系好,回收率和重复性较好,已应用于实际样品的检测。     

Effect of Nb<Superscript>5+</Superscript> charge neutralization substitution on the electrochemical performance of lithium-rich layered oxides

The effect of the Nb⁵⁺ substitution with a charge-compensated strategy in lithium-rich layered oxides (LLOs) Li_1.2Ni_0.13+xCo_0.13-xMn_0.54-xNb_xO₂ (x?=?0, 0.01, 0.02, and 0.03) has been investigated systematically. A hydroxide co-precipitation method followed by a high-temperature solid-state reaction is adopted in the synthesis process. Structural characterization confirms that the low dose substituting of Nb⁵⁺ in the layered structures forms a solid solution, and the samples show low cation mixing and enlarged Li⁺-diffusing channels, which imply favorable high-rate capability. The initial charge/discharge measurements suggest that the oxygen loss from the network during the delithiation process has been suppressed by the substitution of Nb⁵⁺ due to the formation of robust Nb–O bonds and a decrease in TM-O (TMs are transition metals) covalence. Moreover, these Nb–O bonds contribute to the stabilization of the crystalline framework, resulting in an excellent cycle stability with a mitigated voltage decay.     

KBF4非等温固-固相变热性质的测定

利用DTA-TG和DSC热分析技术研究了无机塑晶材料KBF4固-固相变的热性能,测得转变温度为284.13℃,转变焓为105.73J/g.KBF4固-固相变的机理是随着温度的升高,晶体中离子键部分断裂,晶体逐渐由低对称的正交晶系向高对称立方晶系转变,并在这过程中,同时引入化学键的振动和转动无序,从而吸收大量的相变焓.     

超(近)临界水中的化学反应

水作为自然界最常用的绿色介质在化学反应中已经得到广泛应用.近年来,随 着超临界技术的发展,人们对超(近)临界水的认识逐渐深入,以超(近)临界水为介质进 行化学反应的研究引起了人们的极大兴趣,开展了许多卓有成效的工作.本文在介绍超(近)临界水性质的基础上,主要对近年来超(近)临界水中的有机合成、无机化学反应、生物质的转化反应及聚合物的降解等方面的研究进展进行了回顾总结.     

利用直接核反应研究轻丰中子核的奇特结构

直接核反应(包括弹性散射、非弹性散射、转移反应等)是研究丰中子核奇特结构的常用实验手段之一。以6,8He、11Li、11,12Be、14,15B、15,16C等N=8附近核的结构研究为例，综述了如何利用这几种反应从实验上研究丰中子核的奇特结构。利用6,8He，11Be等晕核在质子和氘靶上的弹性散射数据，拟合得到了这些反应体系的有效相互作用(光学势)。利用16C在质子和氘靶上的非弹性散射数据，抽取了16C 的形变参数，结果表明16C的形变不可忽略。利用单核子转移反应，定量研究了8He, 11,12Be等丰中子核基态及低占据态中的p-，s-，以及d-波成分的强度。结果表明:8He基态中的4个价中子，除了可以构成正常的 (0p_3/2)4 组态外，还有一定的几率构成($ 0 p_{3/2} $)2(0p_1/2)2组态；12Be的基态以d波闯入为主，而其临近的11Be的基态以s波闯入为主。     

Facile fabrication of Cu2O/Cu columnar array electrode through dealloying and in situ oxidation for supercapacitor applications

Journal of Solid State Electrochemistry - A Cu2O/Cu columnar array electrode that integrates the active materials and current collector was fabricated through in situ thermal oxidation of the...     

High-internal-ionic liquid-phase emulsions

High-internal-ionic liquid-phase emulsions were formed for the first time. The novel emulsions are very stable and do not involve any volatile organic solvent. They have great potential of applications in different fields, such as material synthesis, extraction, encapsulation, and chemical reactions.     

Water-in-oil-in-water double nanoemulsion induced by CO(2)

The cetyltrimethylammonium bromide (CTAB)/water/heptane emulsion system with different CO(2) pressure has been studied. The phase behavior investigation shows the nanoemulsion can be formed at suitable pressure range. The generalized indirect Fourier transformation (GIFT) analysis of the small-angle X-ray scattering (SAXS) data has drawn a clear picture of the structural information of the nanoemulsion, which reveals that the droplet of emulsion has a double structure with both the outer and inner droplet size in nanometre range. Furthermore, the investigation of the heptane/CTAB/water/CO(2) emulsion system by using electrical conductivity confirms the emulsion type transforms from O/W to W/O/W. In addition, the effect of different CTAB concentration on the nanoemulsion formation has been studied. It is found that enough CTAB concentration is necessary for the inclusion of continuous water into oil droplets. We also explored the application of the W/O/W double nanoemulsion in material synthesis. Interestingly, the hollow silica spheres with double shells were obtained in this CO(2)-induced double nanoemulsion.