排序方式: 共有19条查询结果,搜索用时 62 毫秒
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Chen Chao-Yue Qiao Yu Zhang Lei Wang Xin Yang Ting-Hai 《Research on Chemical Intermediates》2020,46(9):4079-4089
Research on Chemical Intermediates - When synthesizing cyclohexane-annulated pyrazolones from a cyclohexonedicarboxylate derivative with phenylhydrazine under the catalysis of sulfuric acid in the... 相似文献
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本文以氧化石墨烯包覆泡沫镍电极(GO@NF)作为基底,采用水热法在GO@NF基底上原位生长CoO纳米花,同时GO在水热过程中被同步热还原为还原氧化石墨烯(RGO),从而一步制得还原氧化石墨烯包覆泡沫镍负载CoO纳米花电极(CoO/RGO@NF)。使用XRD和SEM对CoO/RGO@NF电极进行表征,发现CoO纳米花均匀生长在泡沫镍三维网络结构上,CoO纳米花为大量针状纳米棒围绕一个中心而成的花状结构,纳米棒的长度约为10 ~ 15 μm,直径约为100 ~ 200 nm。使用循环伏安和线性扫描法测试了CoO/RGO@NF电极电催化CO2的还原性能,在-0.76 V(vs. SHE)电位下,CoO/RGO@NF电极电催化CO2还原的电流效率达到70.9%,产甲酸法拉第效率达到65.2%,甲酸产率为59.8 μmol·h-1·cm-2,且电极可持续稳定电催化还原CO2 4 h,表明CoO/RGO@NF电极对CO2电还原有着优良的催化活性、选择性和稳定性。 相似文献
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Chao-Yue Chen Jian-Guo Sun Fei-Yan Liu Kwok-Pui Fung Ping Wu Zhi-Zhen Huang 《Tetrahedron》2012,68(12):2598-2606
A novel route for the efficient synthesis of a target psoralen moiety, 4,4′-dimethylxanthotoxol, has been developed, which need only four steps using cheap pyrogallol as a starting material. Subsequently, a range of new glycosylated psoralen derivatives were synthesized in good yields with simple procedures and mild reaction conditions. The experiment of biological activity shows that some of the glycosylated psoralen derivatives have antiproliferative activities against human cancer cell lines. A strong photo-induced antiproliferative effects were found under UVA. All of the glycosylated psoralen derivatives exhibited antioxidant activities against the oxidation of DNA induced by Cu2+/glutathione (GSH). Further experiment also demonstrates that the introduction of sugar moieties in some glycosylated psoralen derivatives can improve their antioxidant activities significantly. 相似文献
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1,1,3,3-四(全氟己基乙基)二锡氧烷二聚体在环氧化合物开环反应中的催化作用 总被引:2,自引:0,他引:2
采用氟碳-有机溶剂两相催化体系,考察了1,1,3,3-四(全氟己基乙基)二锡氧烷二聚体(1)在环氧化合物开环反应中的催化作用.结果表明,催化剂(1)在氟碳-有机溶剂两相体系中使环氧苯乙烯和甲醇的开环反应产率高达95%,13CNMR谱表明,开环反应的区域选择性为100%.在氟碳-有机溶剂两相催化体系中以一锅法制备了3-苯基丙酸2-甲氧基-2-苯乙醇酯,收率高,方法简便,催化剂几乎可以定量回收循环使用. 相似文献
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以三聚氰胺和碳酸氢铵混合物为原料,采用简便热解法制备g-C_3N_4纳米管。热解过程中碳酸氢铵分解释放出大量的NH3,能够诱导纳米管的形成。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、红外光谱(IR)、N_2吸附-脱附、紫外-可见漫反射光谱以及紫外可见光谱(UV)等分析测试方法对该光催化剂的微观形貌结构和催化性能进行了表征。以罗丹明光催化降解为模型反应研究了g-C_3N_4纳米管的光催化活性。g-C_3N_4纳米管的表面积明显增大,且能够有效地促进光生电子转移,在可见光下具有较强的光催化性能,降解率在60和120 min时分别能达到95%和99.4%,且循环重复利用5次后降解率不低于92%。 相似文献
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漫反射电磁表面能够提高目标被探测的难度,实现电磁消隐的功能.太赫兹漫反射电磁表面有望在下一代雷达与通信场景中作为一种智能隐身蒙皮使用,具有广阔的应用前景.本文利用石墨烯在太赫兹频段优异的电磁可调特性,并基于谐振模式的开关机理设计了一种反射场具有反相位的石墨烯/金属协同单元结构.且相位的切换由偏置电压动态控制.另一方面,不同于金属材料,石墨烯具有不可忽略的损耗特性,导致了所设计的结构在谐振/非谐振两种反相位状态对应的反射幅度不一致,根据场的干涉与叠加原理,其不利于远场相干相消,难以获得理想的漫反射效果.本文提出了一种将反相位单元结构进行二次组合形成"分子"结构的方法,并将其作为反射表面的基本元素,进而运用粒子群算法,优化"分子"结构的排布方式.计算结果表明,使用这种方法设计的动态漫反射表面,具有收敛速度快、远场峰值小的优势. 相似文献
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Chao-Yue Chen Ting-Hai Yang Chang-Duo Pan Xin Wang 《Journal of carbohydrate chemistry》2019,38(3):179-191
An improved synthesis for 4,4′-dimethylxanthotoxol 2,3,4,6-tetra-O-acetyl-β-D-glucoside (1) starting from resorcinol was developed. Crystallographic analysis of glucoside 1 indicated that the dihedral angles between the mean planes of the tricyclic ring system of adjacent molecules was 54.820(22)° probably due to the steric hindrance caused by the bulky O-glucoside moiety, which prevents the molecules from packing via π···π stacking between the tricyclic cores. The antifungal screening data revealed that glucoside 1 had higher inhibition than its parent compound 4,4′-dimethylxanthotoxol and azoxystrobin against Rhizoctonia solani, Pyricularia grisea, and Alternaria alternate Japanese pear pathotype, with the inhibitory rates of 75.4, 65.7 and 70.1%, respectively, at the 50?µg/mL concentration. 相似文献