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71.
72.
Haiyan An Yang Hu Nan Song Tingliang Mu Shiqiang Bai Yong Peng Liangliang Liu Yu Tang 《Chemical science》2022,13(10):3035
Two-dimensional (2D) metal–organic framework (MOF) based heterostructures will be greatly advantageous to enhance catalytic performance because they increase the contact surface and charge transfer. Herein, a novel 2D heterostructure named CeO2@NiFe-MOFs, in which monolayer NiFe-MOFs is coordinated with ceria (CeO2) to improve catalytic and stability performance, is successfully constructed by the strategy of in situ growth on the surface of ultrathin CeO2 nanosheets being functionalized with monolayer carboxylic acid groups. The 2D heterostructure possesses a sandwich structure, where monolayer NiFe-MOFs are coordinated to both the top and bottom surface of CeO2 nanosheets via joining carboxylic acid groups. In particular, CeO2 with robust coordination plays a significant role in the anchoring of carboxylic acid groups and binding strength of heterostructures. The 2D CeO2@NiFe-MOF heterostructure with a joint effect of metal–ligand coordination not only presents good structural stability but also significantly enhances the oxygen evolution reaction (OER) efficiencies in comparison to bare NiFe-MOFs, achieving a current density of 20 mA cm−2 at a low overpotential of 248 mV as well as durability for at least 40 h. Meanwhile, the electronics, optics, band gap energy and local strains of CeO2 decorated with 2D NiFe-MOFs are different to the properties of bare CeO2. Our study on the construction of an ultrathin CeO2 surface-coordinated and confined MOF layer may pave a new way for novel 2D MOF composites/heterostructures or multi-functional 2D CeO2 materials to be used in energy conversion or other fields.A synthetic strategy to prepare 2D heterostructures from ultrathin CeO2 surface-coordinated metal–organic framework was proposed, proving multiple effects of metal-coordinated interactions in 2D heterostructures. 相似文献
73.
A new photochromic diarylethene derivative with a hydralazine unit was designed and synthesized. It was not only acted as a Zn2+ sensor with the fluorescent color change from dark blue to bright orange, but also acted as a fluorescent sensor for HSO4? with the fluorescent color change from dark blue to bright blue. Furthermore, the derivative also exhibits multi-addressable switching properties by the stimulations of lights and chemical reagents. Based on these characteristics, two combinational logic circuits were constructed with the emission intensity as the output signals, and the UV/vis lights, chemical species as the input signals. 相似文献
74.
75.
以取代的苯氧基替代烷氧基,合成了21种新的O-(1,2,2,2-四氯)乙基-O-取代苯基硫逐磷酰胺酯,通过元素分析、IR、HNMR、^31PNMR和MS对化合物进行鉴定,O-(1,2,2,2-四氯)乙基硫逐磷酰肼在碱性条件下可容易地生成1,3,4,2恶二唑磷杂环戊烷,产确定了其质谱裂解机制,生物活性普筛结果表明,个别化合物具有高效防治根结线虫活性。 相似文献
76.
稀溶液粘度法研究聚合物之间混溶性 总被引:6,自引:2,他引:6
介绍了几种粘度法判据,并对溶液中高分子-高分子,高分子-溶剂分子间的相互作用对混合物溶液粘度的影响进行了较为深入的讨论。 相似文献
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78.
A General,Concise Strategy that Enables Collective Total Syntheses of over 50 Protoberberine and Five Aporhoeadane Alkaloids within Four to Eight Steps 下载免费PDF全文
Shiqiang Zhou Prof. Dr. Rongbiao Tong 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(21):7084-7089
A concise, catalytic, and general strategy that allowed efficient total syntheses of 22 natural 13‐methylprotoberberines within four steps for each molecule is reported. This synthesis represents the most efficient and shortest route to date, featuring three catalytic processes: CuI‐catalyzed redox‐A3 reaction, Pd‐catalyzed reductive carbocyclization, and PtO2‐catalyzed hydrogenation. Importantly, this new strategy to the tetracyclic framework has also been applied to the collective concise syntheses of >30 natural protoberberines (without 13‐methyl group) and five aporhoeadane alkaloids. 相似文献
79.
通过编织Kevlar/Epoxy复合材料层合板的平头弹冲击实验,分析了结构在不同冲量下的变形失效模式以及结构的抗冲击性能。实验表明复合板的变形失效模式主要表现为:(1)弹性变形;(2)复合板表面嵌入失效及整体塑性大变形;(3)背面纤维拉伸断裂及分层失效。基于实验研究,运用LS-DYNA 971有限元程序对铺层数不同的复合板在冲击载荷作用下的动态响应过程进行了数值模拟,模拟结果与实验吻合较好,子弹作用区域边缘处首先发生近似圆形的嵌入失效,而在板背面发生近似正方形的破坏区域;计算中重点分析了铺层数对结构动力响应的影响,在一定冲量范围内,通过对铺层数的优化,能够有效地减小后面板挠度,提高结构的能量吸收效率,增强结构的抗冲击性能。 相似文献
80.
Shiqiang Yan Ning Ding Wei Zhang Peng Wang Yingxia Li Ming Li 《Journal of carbohydrate chemistry》2013,32(7):571-583
An efficient, convenient protocol for the preparation of per-O-acetylated p-tolylthio glycosides is described. Treatment of various unprotected sugars, including 2-deoxy-2-amino sugars, sialic acid, lactose, and maltose, with acetic anhydride using SnCl4 as a catalyst, and subsequently with p-tolylthiol, furnished the corresponding thioglycosides in 71%–90% yield under solvent-free conditions. 相似文献