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991.
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993.
微波干法催化芳香醛与绕丹宁及N-苯基绕丹宁的缩合反应 总被引:1,自引:0,他引:1
利用微波辐射和固体碱性载体试剂催化绕丹宁及N-苯基绕丹宁和芳香醛的缩合反应合成了14个绕丹宁衍生物并研究了影响反应的因素。 相似文献
994.
亚铁氰化钾-NO2--鲁米诺化学发光体系测定痕量亚硝酸盐的研究 总被引:17,自引:0,他引:17
本文在调查和了解天津市独立科技信息服务机构现状的基础上,研究和探讨了其调整原则和调整目标,确立了调整的步骤和要点。最后提出天津市独立科技信息服务机构的七点调整对策。 相似文献
995.
合成了邻菲咯啉-18-冠-6等四种含邻菲咯啉结构的冠醚化合物, 并用作载体制备伯胺电极, 以苄胺为模型化合物, 研究了电极特性, 并制备了测试美西律药物的选择性电极。研究了实验条件对电极性能的影响。用正交多项式回归法优化电极的膜组成。苄胺电极的线性范围1.0×10^-5~0.1mol/L, 斜率55.6mV/pc, 检测下限2.0×10^-6mol/L。美西律电极的线性范围6.0×10^-6~0.1mol/L, 检测下限8.0×10^-7mol, 斜率58.0mV/pc。同时研究了冠醚推动伯胺穿透大块液膜的传输行为。 相似文献
996.
Dr. Yue Wang Fang Zhou Prof. Dr. Qingtao Meng Songhe Zhang Dr. Hongmin Jia Dr. Cuiping Wang Dr. Run Zhang Prof. Dr. Zhiqiang Zhang 《化学:亚洲杂志》2021,16(21):3419-3426
The detection of changes in the reactive oxygen species (ROS)/reactive sulfur species (RSS) couple is important for studying the cellular redox state. Herein, we developed a 1,8-naphthalimide-based fluorescence probe ( NI ) for the reversible detection of bisulfite (HSO3−) and hydrogen peroxide (H2O2) in vitro and in vivo. NI has been designed with a reactive ethylene unit which specifically reacts with HSO3− by a Michael addition reaction mechanism, resulting in the quenching of yellow fluorescence at 580 nm and the appearing of green fluorescence at 510 nm upon excitation at 500 nm and 430 nm, respectively. The addition product ( NI−HSO3 ) could be specifically oxidized to form the original C=C bond of NI , recovering the fluorescence emission and color. The detection limits of NI for HSO3− and NI−HSO3 for H2O2 were calculated to be 2.05 μM and 4.23 μM, respectively. The reversible fluorescence response of NI towards HSO3−/H2O2 couple can be repeated for at least five times. NI is reliable at a broad pH range (pH 3.0–11.5) and features outstanding selectivity, which enabled its practical applications in biological and food samples. Monitoring the reversible and dynamic inter-conversion between HSO3− and H2O2 in vitro and in vivo has been verified by fluorescence imaging in live HeLa cells, adult zebrafish and nude mice. Moreover, NI has been successfully applied to detect of HSO3− levels in food samples. 相似文献
997.
The generation of free radicals is a key process in the formation and the collapse of the bubbles in water, however, the direct and dynamic observation of the radicals in this process at single bubbles has never been achieved. Here, the hydroxyl (OH.) and oxygen (O2.−) radicals at single oxygen bubbles are continuously traced using chemiluminescence (CL), in which these radicals at the bubble react with the surrounding luminol in the solution emitting the light. Varied increase trends of luminescence are observed in the generation of a bubble, floating, short parking at the water/air interface and the final explosion, revealing the complexity in the distribution of radicals at the bubble unprecedentedly. Despite more radicals are observed at the bubble generated at a deep position under the water for the stabilization, almost the same amount of radicals are included in the bubbles that is independent on the water pressure during the production of the bubble. This rich information collected from the dynamic study of bubbles illustrates the complicated generation and distribution process of radicals at the bubbles, and will facilitate the understanding of the function about the bubbles. 相似文献
998.
Xiuzhi Duan Xuchu Wang Yiyi Xie Pan Yu Tingting Zhuang Yingzhi Zhang Liuyu Fang Ying Ping Weiwei Liu Zhihua Tao 《Electrophoresis》2021,42(14-15):1411-1418
999.
HoU Baoxiu MA Linlin ZANG Xiaohuan SHANG Ningzhao SONG Jianmin ZHAO Xiaoxian WANG Chun QI Jian WANG Jiangyan YU Ranbo 《高等学校化学研究》2021,37(2):265-273
An easy and delicate approach using cheap carbon source as conductive materials to construct 3D sequential porous structural Na3V2(PO4)3/C(NVP/C)with high performance for cathode materials of sodium ion battery is highly desired.In this paper,the NVP/C with 3D sequential porous structure is constructed by a delicate approach named as“cooking porridge”including evaporation and calcination stages.Especially,during evaporation,the viscosity of NVP/C precursor is optimized by controlling the adding quantity of citric acid,thus leading to a 3D sequential porous structure with a high specific surface area.Furthermore,the NVP/C with a 3D sequential porous structure enables the electrolyte to interior easily,providing more active sites for redox reaction and shortening the diffusion path of electron and sodium ion.Therefore,benefited from its unique structure,as cathode material of sodium ion batteries,the 3D sequential porous structural NVP/C exhibits high specific capacities(115.7,88.9 and 74.4 mA·h/g at current rates of 1,20 and 50 C,respectively)and excellent cycling stability(107.5 and 80.4 mA·h/g are remained at a current density of 1 C after 500 cycles and at a current density of 20 C after 2200 cycles,respectively). 相似文献
1000.