Flame-retardant effect of cross-linked phosphazene derivatives and pentaerythritol derivatives on polypropylene

Journal of Thermal Analysis and Calorimetry - A phosphazene-based flame retardant (PBFA) was synthesized by hexachlorocyclotriphosphazene and N-aminoethylpiperazine. To improve the flame retardancy...     

C.I.颜料红177中间体的制备工艺改进

本文较为系统地研究了铜粉催化剂加入方式对C.I.颜料红177中间体4,4'-二氨基-1,1'-二蒽醌-3,3'-二磺酸(DAS)合成过程中的乌尔曼偶联反应速率的影响规律。 研究结果表明,在55 ℃较佳反应温度下,先加入与溴氨酸钠质量比为2:5的铜粉,反应一段时间后再加入与溴氨酸钠的质量比为1:5的铜粉,与一次性加入与溴氨酸钠的质量比为3:5的铜粉相比较,综合反应时间可节省2~3 h。 另外,对于DAS中混有的铜盐,采取在制备过程中加入柠檬酸的方法予以去除,此举可提高DAS的纯度。 当铜粉与柠檬酸的质量比为6:1时,可使DAS中铜盐的含量小于0.001%。 此外还探究了蒸馏后滤液的剩余量对DAS收率的影响,结果表明,滤液的剩余量在20 mL时,DAS的收率在95%以上。 基于本文的研究结果提出,欲进一步提高该反应的收率,需要寻找更高效的催化剂。     

In Situ Electropolymerization Enables Ultrafast Long Cycle Life and High‐Voltage Organic Cathodes for Lithium Batteries

Organic cathode materials have attracted extensive attention because of their diverse structures, facile synthesis, and environmental friendliness. However, they often suffer from insufficient cycling stability caused by the dissolution problem, poor rate performance, and low voltages. An in situ electropolymerization method was developed to stabilize and enhance organic cathodes for lithium batteries. 4,4′,4′′‐Tris(carbazol‐9‐yl)‐triphenylamine (TCTA) was employed because carbazole groups can be polymerized under an electric field and they may serve as high‐voltage redox‐active centers. The electropolymerized TCTA electrodes demonstrated excellent electrochemical performance with a high discharge voltage of 3.95 V, ultrafast rate capability of 20 A g^?1, and a long cycle life of 5000 cycles. Our findings provide a new strategy to address the dissolution issue and they explore the molecular design of organic electrode materials for use in rechargeable batteries.     

Bi-2223喷雾热分解粉末热处理工艺优化

Bi-2223 带材目前在电流引线、 超导电机、 超导电缆、 超导限流器等领域实现了许多示范性应用, 载流性能是表征其性能的重要指标, 而高质量的前驱体粉末是最终带材性能的关键保障. 本文选用具有工艺简单、 粉末效率高、 批次稳定性好等优点的喷雾热分解法制备的Bi-2223 前驱体粉末, 利用 TG-DSC、XRD、SEM 等测试手段对低氧条件下不同保温时间烧结的粉末进行分析, 并结合最终带材的载流性能测试结果, 获得了最优粉末烧结参数, 为后续喷雾热分解粉末的进一步生成 Bi-2223 相以及高性能粉末的制备提供了依据.     

电解铜箔表面电沉积Zn-Ni-P-La合金工艺

为了缓解我国高性能铜箔依靠进口的局面,进行了将类金属(P)和稀土金属(La)引入电解铜箔锌镍合金镀层中以获得高耐腐蚀性铜箔的实验。 利用电子能谱(XPS)、X射线衍射(XRD)、扫描电子显微镜(SEM)等技术手段分析镀层质量。 在最佳工艺下获得非晶态Zn-Ni-P-La合金镀层,镀层表面平整均匀、结晶致密,未钝化的情况下,铜箔镀件在180 ℃烘箱中保持1 h不变色,表现出较理想的抗氧化和抗腐蚀能力。 表明镀层中适量的P和稀土La对改善镀层质量有着重要的作用,具有较好的工业应用前景。     

Selective enrichment and quantification of okadaic acid in shellfish using an immunomagnetic‐bead‐based liquid chromatography with tandem mass spectrometry assay

Okadaic acid is a marine biotoxin that primarily occurs in shellfish and can cause diarrheic shellfish poisoning in humans. When analyzing biological samples using liquid chromatography with tandem mass spectrometry, the presence of complex matrices is a major issue. Thus, it is crucial to selectively and simply extract the target analyte from samples and minimize matrix effects simultaneously. To meet this need, an immunomagnetic‐bead‐based liquid chromatography with tandem mass spectrometry method was developed to detect okadaic acid in shellfish. Magnetic beads bound to monoclonal antibody against okadaic acid were used as affinity probes to specifically enrich okadaic acid in samples, which effectively eliminated matrix effects. A magnetic separator was used to aggregate and separate magnetic particles from sample matrices, and methanol was used to elute okadaic acid from the magnetic beads. Standard solution prepared with methanol was employed directly for quantitative analysis. Several experimental conditions were optimized to improve performance. The method is of interest as a rapid (10 min) sample clean‐up and selective enrichment tool, and it showed good linearity and sensitivity, with reported limits of detection and quantitation of 3 and 10 μg/kg, respectively. Fifty‐three shellfish samples from an aquatic products market were tested using this method, and four samples positive for okadaic acid were found.     

In Situ Electropolymerization Enables Ultrafast Long Cycle Life and High-Voltage Organic Cathodes for Lithium Batteries

Organic cathode materials have attracted extensive attention because of their diverse structures, facile synthesis, and environmental friendliness. However, they often suffer from insufficient cycling stability caused by the dissolution problem, poor rate performance, and low voltages. An in situ electropolymerization method was developed to stabilize and enhance organic cathodes for lithium batteries. 4,4′,4′′-Tris(carbazol-9-yl)-triphenylamine (TCTA) was employed because carbazole groups can be polymerized under an electric field and they may serve as high-voltage redox-active centers. The electropolymerized TCTA electrodes demonstrated excellent electrochemical performance with a high discharge voltage of 3.95 V, ultrafast rate capability of 20 A g⁻¹, and a long cycle life of 5000 cycles. Our findings provide a new strategy to address the dissolution issue and they explore the molecular design of organic electrode materials for use in rechargeable batteries.     

The characteristic of sound propagation in deep water and underwater source localization in the direct zone

The multiple-path sound propagation in deep water is conducive to source localization of an underwater target.The transmission losses(TLs) and broadband pulse multiple-path propagation characteristics from a deep receiver is analyzed by using the experimental data from deep water area in the South China Sea(SCS).The results indicate that the width of the direct zone near the bottom of 4300 m water depth is about 30 km.The TLs in the direct zone near the bottom are much less than those in the shadow zone.It is meaningful for underwater sound source detection.Moreover,the time delay between the direct path and the bottomsurface-reflected path for a receiver near the bottom decreases monotonically with the source range.According to the linear relationship between the time delay of multipath and source range,a source localization method is presented to estimate the range of underwater target.The experimental results show that the estimated ranges are consistent with the global position system(GPS) measurements,and the mean square error of the estimation results is less than 0.28 km.     

铁硒基超导材料实用化研究进展

由于铁基超导体含有铁磁性元素以及具有极高的上临界场等特性, 引发了科学家对其理论和实用化研究的热潮. 铁基超导体主要分为四个体系: “1111”体系、 “122”体系、 “111 ”体系和“11 ”体系. 其中, “11 ”体系中的 FeSe基超导材料由于结构简单、 单晶制备容易以及不含有毒元素等优势, 使其成为了研究铁基超导材料的热门体系, 同时也成为了新型实用化超导材料的研究热点. 本文在简要介绍铁基超导材料和 FeSe 基超导材料的基础上, 重点介绍了实用化 FeSe 基超导材料多晶块体、 线带材以及薄膜在制备工艺以及性能等方面的研究进展, 最后对其相关领域今后的发展做出展望