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221.
Hailong Xiong Hongru Zhou Ge Sun Zhilin Liu Liangliang Zhang Ling Zhang Fei Du Zhen‐An Qiao Sheng Dai 《Angewandte Chemie (International ed. in English)》2020,59(27):11053-11060
Mesoporous metal oxides (MMOs) have been demonstrated great potential in various applications. Up to now, the direct synthesis of MMOs is still limited to the solvent induced inorganic‐organic self‐assembly process. Here, we develop a facile, general, and high throughput solvent‐free self‐assembly strategy to synthesize a series of MMOs including single‐component MMOs and multi‐component MMOs (e.g., doped MMOs, composite MMOs, and polymetallic oxide) with high crystallinity and remarkable porous properties by grinding and heating raw materials. Compared with the traditional solution self‐assembly process, the avoidance of solvents in this method not only greatly increases the yield of target products and synthesis efficiency, but also reduces the environmental pollution and the consumption of cost and energy. We believe the presented approach will pave a new avenue for scalable production of advanced mesoporous materials for various applications. 相似文献
222.
Qiao Ma Yanhui Wang Gavin Chit Tsui 《Angewandte Chemie (International ed. in English)》2020,59(28):11293-11297
A stereoselective Pd(PPh3)4‐catalyzed C?F bond alkynylation of tetrasubstituted gem‐difluoroalkenes with terminal alkynes has been developed. This method gives access to a great variety of conjugated monofluoroenynes bearing a tetrasubstituted alkene moiety with well‐defined stereochemistry. Chelation‐assisted oxidative addition of Pd to the C?F bond is proposed to account for the high level of stereocontrol. An X‐ray crystal structure of a key monofluorovinyl PdII intermediate has been obtained for the first time as evidence for the proposed mechanism. 相似文献
223.
Feiyu Zhao Xue Luo Lixiang Liu Jianhang Lv Prof. Xianping Fan Dr. Xvsheng Qiao Prof. Yang Xu Prof. Lorenz Kienle Prof. Xianghua Zhang Prof. Guodong Qian 《Chemphyschem》2020,21(5):397-405
GeSe micro-sheets and micro-belts have been synthesized by a facile one-pot wet chemical method in 1-octadecene solvent and oleic acid solvent, respectively. The adsorption of more oleic acid molecules on the (002) plane promoted growth along [010] direction of the GeSe micro-belts and limited carrier transport in this direction, resulting in higher carrier concentration and mobility of the GeSe micro-belts. The performance of the photodetectors based on the single GeSe micro-sheet and the single GeSe micro-belt was investigated under illumination at 532 nm, 980 nm and 1319 nm. Both, photodetectors based on a single GeSe micro-sheet and a single GeSe micro-belt, exhibit a high photoresponse, short response/recovery times, and long-term durability. Moreover, the photodetector based on a single GeSe micro-belt displays a broadband response with a high responsivity (5562 A/W at 532 nm, 1546 A/W at 980 nm) and detectivity (3.01×1012 Jones at 532 nm, 8.38×1011 Jones at 980 nm). These excellent characteristics render single GeSe micro-belts very interesting for use as highly efficient photodetectors, especially in the NIR region. 相似文献
224.
Tianjiao Qiao Yicheng Wang Sujuan Zheng Huiying Kang Guangxin Liang 《Angewandte Chemie (International ed. in English)》2020,59(33):14111-14114
The first total syntheses of three unusual norrisolide‐type rearranged spongian diterpenes, cheloviolene C, seconorrisolide B, and seconorrisolide C, have been accomplished via a common intermediate through late‐stage ring‐scissoring. The synthesis features a Wolff ring contraction for the synthesis of the trans‐hydrindane system, and a crucial retro Diels–Alder reaction/intramolecular ene cyclization for the rapid stereoselective construction of the furo[2,3‐b]furan system, which is commonly seen in rearranged spongian diterpenes. 相似文献
225.
Xiaoya Yu Linzhong Wu Di Yang Muhan Cao Xing Fan Haiping Lin Qixuan Zhong Yong Xu Qiao Zhang 《Angewandte Chemie (International ed. in English)》2020,59(34):14527-14532
Hydrochromic materials that can reversibly change color upon water treatment have attracted much attention owing to their potential applications in diverse fields. Herein, for the first time, we report that space‐confined CsPbBr3 nanocrystals (NCs) are hydrochromic. When CsPbBr3 NCs are loaded into a porous matrix, reversible transition between luminescent CsPbBr3 and non‐luminescent CsPb2Br5 can be achieved upon the exposure/removal of water. The potential applications of hydrochromic CsPbBr3 NCs in anti‐counterfeiting are demonstrated by using CsPbBr3 NCs@mesoporous silica nanospheres (around 100 nm) as the starting material. Owing to the small particle size and negatively charged surface, the as‐prepared particles can be laser‐jet printed with high precision and high speed. We demonstrate the excellent stability over repeated transformation cycles without color fade. This new discovery may not only deepen the understanding of CsPbX3, but also open a new way to design CsPbX3 materials for new applications. 相似文献
226.
Nan Wang Xiaoli Dong Bingliang Wang Zhaowei Guo Zhuo Wang Renhe Wang Xuan Qiu Yonggang Wang 《Angewandte Chemie (International ed. in English)》2020,59(34):14577-14583
Aqueous zinc (Zn) batteries have been considered as promising candidates for grid‐scale energy storage. However, their cycle stability is generally limited by the structure collapse of cathode materials and dendrite formation coupled with undesired hydrogen evolution on the Zn anode. Herein we propose a zinc–organic battery with a phenanthrenequinone macrocyclic trimer (PQ‐MCT) cathode, a zinc‐foil anode, and a non‐aqueous electrolyte of a N,N‐dimethylformamide (DMF) solution containing Zn2+. The non‐aqueous nature of the system and the formation of a Zn2+–DMF complex can efficiently eliminate undesired hydrogen evolution and dendrite growth on the Zn anode, respectively. Furthermore, the organic cathode can store Zn2+ ions through a reversible coordination reaction with fast kinetics. Therefore, this battery can be cycled 20 000 times with negligible capacity fading. Surprisingly, this battery can even be operated in a wide temperature range from ?70 to 150 °C. 相似文献
227.
Meijuan Xu Zhina Qiao Genshu Huang Mengfei Long Taowei Yang Xian Zhang Minglong Shao Zhenghong Xu Zhiming Rao 《Journal of separation science》2020,43(14):2936-2948
l ‐Arginine has many special physiological and biochemical functions, with wide applications in the food and pharmaceutical industry. Few studies on the purification of l ‐arginine from fermentation broth have been conducted; however, none of them were systematic enough for industrial scale‐up. Therefore, it is necessary to develop a highly efficient and systematic process for the purification of l ‐arginine from fermentation broth. In this study, we screened out a cation exchange resin, D155, having high exchange capacity, high selectivity, and easy elution capacity, and analyzed its adsorption isotherm, thermodynamics, and kinetics using different models. Further, the process parameters of fixed‐bed ion exchange adsorption and elution were optimized, and the penetration curve during the operation was modeled. Based on the fixed‐bed ion‐exchange parameters, a 30‐column continuous ion‐exchange system was designed, and the flow velocity in each zone was optimized. Finally, to obtain a high purity of l ‐arginine, the purification tests were conducted using anion exchange resin 711, and an l ‐arginine yield of 99.1% and purity of 98.5% was obtained. This effective and economical method also provides a promising strategy for separation of other amino acids from the fermentation broth, which is of great significance to the l ‐arginine fermentation industry. 相似文献
228.
Nonlinear Dynamics - Periodic event-triggered control (PETC) is an aperiodic sampling technique aiming at reducing the working time of the sensors and the transmissions in the feedback control... 相似文献
229.
Henghui Zhang Xiaoli Wang Dongliang He Dongliang Zou Runzhu Zhao Huifang Wang Shuying Li Yongping Xu Buhailiqiemu Abudureheman 《Molecules (Basel, Switzerland)》2022,27(1)
In the present work, the extraction process of total flavonoids (TFs) from X. sorbifolia flowers by ultrasound-assisted extraction was optimized under the response surface methodology (RSM) on the basis of single-factor experiments. The optimal extraction conditions were as follows: ethanol concentration of 80%, solid–liquid ratio of 1:37 (g/mL), temperature of 84 °C, and extraction time of 1 h. Under the optimized conditions, the extraction yield of the TFs was 3.956 ± 0.04%. The radical scavenging capacities of TFs against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) were much greater than that of rutin. The results of antibacterial experiments indicated that the TFs displayed strong inhibitory activities on E. coli, S. aureus and Bacillus subtilis. Therefore, X. sorbifolia flowers can be used as a novel source of natural flavonoids, and the TFs have potential applications as natural antioxidants or antibacterial agents in the food and pharmaceutical industries. 相似文献
230.
The linear 2-arboricity la_2(G) of a graph G is the least integer k such that G can be partitioned into k edge-disjoint forests,whose component trees are paths of length at most 2.In this paper,we prove that if G is a 1-planar graph with maximum degree Δ,then la_2(G)≤[(Δ+1)/2]+7.This improves a known result of Liu et al.(2019) that every 1-planar graph G has la_2(G)≤[(Δ+1)/2]+14.We also observe that there exists a 7-regular 1-planar graph G such that la_2(G)=6=[(Δ+1)/2]+2,which implies that our solution is within 6 from optimal. 相似文献