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21.
Zn3V3O8 two-dimensional micro sheets are successfully synthesized by combination of solvothermal method and heat treatment. The Zn3V3O8 has better electrochemical performances after calcinations. 相似文献
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Koketsu M Choi SY Ishihara H Lim BO Kim H Kim SY 《Chemical & pharmaceutical bulletin》2002,50(12):1594-1596
This study reports depigmenting potency of 1,3-selenazol-4-one derivatives, which would be based upon the finding of direct inhibition to mushroom tyrosinase. 1,3-Selenazol-4-one derivatives exhibited inhibitory effect on dopa oxidase activity of mushroom tyrosinase. In this study, inhibitory effects of six kinds of 1,3-selenazol-4-one derivatives (A, B, C, D, E and F) on mushroom tyrosinase were investigated. Compounds at a concentration of 500 microM exhibited 33.4-62.1% of inhibition on dopa oxidase activity of mushroom tyrosinase. Their inhibitory effects were higher than that of kojic acid (31.7%), a well known tyrosinase inhibitor. 2-(4-Methylphenyl)-1,3-selenazol-4-one (A) exhibited the strongest inhibitory effect among them dose-dependently and in competitive inhibition manner. 相似文献
24.
氨基酸柱前衍生化的3种新荧光试剂的光谱特性及高效液相色谱研究 总被引:1,自引:2,他引:1
合成了3种新的荧光标记试剂:吖啶-N-乙酰氯,咔唑-9-乙酰氯和咔唑-9-丙酰氯。它们的最大发射降激发波长分别为430nm,368nm,和365nm。3种衍生化试剂与氨基酸形成的衍生物在pH6.5的条件下结合梯度洗脱程序在C18反相柱上对色谱条件进行了优化。 相似文献
25.
连接基团链长度对季铵盐二聚表面活性剂C12-s-C12·2Br在水溶液中胶团化行为的影响 总被引:12,自引:1,他引:12
用电导法、稳态荧光法和粘度法研究了二聚表面活性剂C12-s-C12*2Br分子中的连接基团链长度(s=2, 3, 4, 6)对其在水溶液中聚集行为的影响. 实验发现, C12-s-C12*2Br的胶团生成能力远比其单体C12TABr强得多, 前者cmc值较后者降低一个数量级. 胶团聚集数N随表面活性剂浓度c的增大而增大, 其中当s=2时的N值在c=7.7 mmol/L后开始急剧增大. 计算结果表明, 此时胶团形状发生了明显变化, 形成了椭球形的胶团. 粘度测定结果也证实了这一点. 相似文献
26.
Wei Ge Chao Liu Yatao Xu Jiayao Zhang Weili Si Wenjun Wang Changjin Ou Xiaochen Dong 《Chemical science》2022,13(32):9401
Organic charge-transfer complexes (CTCs) can function as versatile second near-infrared (NIR-II) theranostic platforms to tackle complicated solid tumors, while the structure–property relationship is still an unanswered problem. To uncover the effect of molecular stacking modes on photophysical and biochemical properties, herein, five ferrocene derivatives were synthesized as electron donors and co-assembled with electron-deficient F4TCNQ to form the corresponding CTCs. The crystalline and photophysical results showed that only herringbone-aligned CTCs (named anion-radical salts, ARS NPs) possess good NIR-II absorption ability and a photothermal effect for short π–π distances (<3.24 Å) and strong π-electron delocalization in the 1D F4TCNQ anion chain. More importantly, the ARS NPs simultaneously possess ·OH generation and thiol (Cys, GSH) depletion abilities to perturb cellular redox homeostasis for ROS/LPO accumulation and enhanced ferroptosis. In vitro experiments, FcNEt-F4 NPs, and typical ARS NPs, show outstanding antitumor efficiency for the synergistic effect of NIR-II photothermal therapy and ferroptosis, which provides a new paradigm to develop versatile CTCs for anti-tumor application.Based on crystal engineering of charge transfer complexes (CTCs), ferrocene-based CTCs, with Fenton-catalyzing, biothiol-responsive and NIR-II photothermal abilities, were controllably developed and the structure–property relationship was revealed. 相似文献
27.
基于Visco-SCRAM模型的侵彻装药点火研究 总被引:1,自引:0,他引:1
针对弹体侵彻过程中装药的安全性,基于黏弹性统计裂纹力学(visco-statistical crack mechanics, Visco-SCRAM)模型计算装药整体温升、装药裂纹摩擦生热以及弹体装药与壳体摩擦生热,考察这3种机制对装药温升的贡献以及侵彻装药的点火机制,得到了装药点火对应的弹体侵彻临界初始速度。结果表明:(1)装药与弹体内壁摩擦生热对装药温升有一定贡献,随着弹体初始撞击速度的提高,摩擦生热对温升的贡献逐渐增大;(2)黏性、损伤和绝热体积变化导致的装药整体温升对装药点火的作用有限; (3)裂纹摩擦形成热点是侵彻装药点火的物理机制;(4)采用Visco-SCRAM模型可预测低强度、长脉冲载荷作用下的装药点火响应。
相似文献28.
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Frantisek Mikes Hongxiang Teng Yasuhiro Koike Yoshiyuki Okamoto 《Journal of polymer science. Part A, Polymer chemistry》2012,50(22):4717-4720
Copolymerizations of hexafluoroisobutylene (HFIB) with vinyl pentafluorobenzoate (VPFB) and vinyl trifluoroacetate (VTFA) were carried out in bulk using perfluorodibenzoyl peroxide as the radical initiator. The copolymers obtained were characterized by proton and fluorine NMR spectroscopy. The monomer reactivity ratios in the polymerization of HFIB with VPFB were r1 (HFIB) = 0, r2 (VPFB) = 0.373, and r1r2 = 0. The results indicated that these copolymers have alternating structures. Similarly, the copolymers of HFIB and VTFA also showed alternating structures. The films of HFIB‐co‐VPFB were prepared by casting THF solution of polymers. Films obtained were flexible and transparent. The refractive indices of copolymers were 1.4549, 1.4490, and 1.4438 at 532, 633, and 839 nm, respectively. The average Tgs of HFIB‐co‐VTFA and HFIB‐co‐VPFB were 52 and 71 °C, respectively. From these results, the Tg of the hypothetical HFIB homopolymer is postulated to be in between 70 and 90 °C, which may be useful in the assessment of Tgs of HFIB copolymers with other vinyl monomers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献