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981.
Star-shaped PCL with one to five arms were synthesized by ROP. They have the same crystal structure as linear PCL, indicating that the central cores are located in amorphous regions. The influence of arm length and number on crystallization and melting behavior were studied by DSC, POM, and through the Avrami equation. A model is proposed to analyze the enzymatic degradation process of star-shaped polymers. The multi-arm structure and the limitation of the central cores on the chain mobility of each arm are considered to be the primary factors influencing the characteristic crystallization and enzymatic degradation behavior of star-shaped PCLs. 相似文献
982.
全固态锂电池因其优异的安全性和高能量密度成为储能领域的重点研究内容。硫化物电解质因其高离子电导率、良好电极/电解质界面兼容性及易加工性,有力推动了硫化物基全固态锂电池的发展。本文首先从实验室研究阶段出发,从正极/电解质界面、硫化物电解质自身及负极/电解质界面三方面阐述了硫化物基全固态锂电池现阶段面临的主要问题,并介绍了相关的解决策略。随后从硫化物基全固态锂电池的实用化生产角度出发,介绍了电极/电解质膜的制膜工艺、软包电池的装配相关问题、高载正极的设计及硫化物电解质的大规模、低成本制备。最后展望了硫化物基全固态锂电池的未来研究方向和发展趋势。 相似文献
983.
Haokun Li Gan Xu Shuchang Li Yuhao Wu Dr. Zhenpin Lu 《Chemical record (New York, N.Y.)》2023,23(12):e202300238
Electron-precise B−B bonded compounds are valuable reagents in organic syntheses, which can be used as key starting material for the synthesis of functionalized organoboranes. Bis(pinacolato)diborane(4) B2pin2 and its derivatives are among the most studied diboron species. However, their B−B bonds usually need to be activated by transition metal catalysts or bases for further transformations. Recently, many well-designed/reactive electron-precise B−B bonded compounds have been developed, which could facilitate direct reactions with small molecules, unsaturated substrates, and electrophiles. This review highlights the synthesis, structure, and reactivity of neutral and anionic B−B bonded compounds. 相似文献
984.
Peng Wumao Huang Chaopeng Zhang Shaohua Chen Yu Han Yanjun Jiang Liang Qian Linmao 《Journal of Solid State Electrochemistry》2023,27(2):467-477
Journal of Solid State Electrochemistry - 9Cr18Mo stainless bearing steel is commonly used to manufacture rolling bearings in aerospace. Excellent surface quality is required to improve the service... 相似文献
985.
Qi-Chao Gan Jia Qiao Dr. Chao Zhou Rui-Nan Ci Dr. Jia-Dong Guo Dr. Bin Chen Prof. Dr. Chen-Ho Tung Prof. Dr. Li-Zhu Wu 《Angewandte Chemie (International ed. in English)》2023,62(17):e202218391
Represented herein is the first example of N-radical generation direct from N−H bond activation under mild and redox-neutral conditions. The in situ generated N-radical intercepts a reduced heteroarylnitrile/aryl halide for C−N bond formation under visible-light irradiation of quantum dots (QDs). A series of aryl and alkylamines with heteroarylnitriles/aryl halides exhibit high efficiency, site-selectivity and good functional-group tolerance. Moreover, consecutive C−C and C−N bond formation using benzylamines as substrates is also achieved, producing N-aryl-1,2-diamines with H2 evolution. The redox-neutral conditions, broad substrate scope, and efficiency of N-radical formation are advantageous for organic synthesis. 相似文献
986.
Dr. Zhen Du Dr. Xin Wang Dr. Xiao Zhang Dr. Zhanjun Gu Dr. Xiaoyi Fu Dr. Shaoju Gan Dr. Ting Fu Dr. Sitao Xie Prof. Dr. Weihong Tan 《Angewandte Chemie (International ed. in English)》2023,62(23):e202302525
Carbon monoxide (CO) is an endogenous signaling molecule with broad therapeutic effects. Here, a multifunctional X-ray-triggered carbon monoxide (CO) and manganese dioxide (MnO2) generation nanoplatform based on metal carbonyl and scintillating nanoparticles (SCNPs) is reported. Attributed to the radioluminescent characteristic of SCNPs, UV-responsive Mn2(CO)10 is not only indirectly activated to release CO by X-ray but can also be degraded into MnO2. A high dose of CO can be used as a glycolytic inhibitor for tumor suppression; it will also sensitize tumor cells to radiotherapy. Meanwhile MnO2, as the photolytic byproduct of Mn2(CO)10, has both glutathione (GSH) depletion and Fenton-like Mn2+ delivery properties to produce highly toxic hydroxyl radical (⋅OH) in tumors. Thus, this strategy can realize X-ray-activated CO release, GSH depletion, and ⋅OH generation for cascade cancer radiosensitization. Furthermore, X-ray-activated Mn2+ in vivo demonstrates an MRI contrast effect, making it a potential theranostic nanoplatform. 相似文献
987.
Dongwen Guo Kai Jiang Hui Gan Yanwei Ren Prof. Jinxing Long Prof. Yingwei Li Prof. Biaolin Yin 《Angewandte Chemie (International ed. in English)》2023,62(39):e202304662
Developing well-defined structures and desired properties for porous organic polymer (POP) supported catalysts by controlling their composition, size, and morphology is of great significance. Herein, we report a preparation of polyaniline (PANI) supported Pd nanoparticles (NPs) with controllable structure and morphology. The protocol involves the introduction of MnO2 with different crystal structures (α, β, γ, δ, ϵ) serving as both the reaction template and the oxidant. The different forms of MnO2 each convert aniline to a PANI that contains a unique regular distribution of benzene and quinone. This leads to the Pd/PANI catalysts with different charge transfer properties between Pd and PANI, as well as different dispersions of the metal NPs. In this case, the Pd/ϵ-PANI catalyst greatly improves the turnover frequency (TOF; to 88.3 h−1), in the reductive coupling of furfural derivatives to potential bio-based plasticizers. Systematic characterizations reveal the unique oxidation state of the support in the Pd/ϵ-PANI catalyst and coordination mode of Pd that drives the formation of highly dispersed Pd nanoclusters. Density functional theory (DFT) calculations show the more electron rich Pd/PANI catalyst has the lower energy barrier in the oxidative addition step, which favors the C−C coupling reaction. 相似文献
988.
Six new C21 steroidal glycosides 1 – 6 were isolated from the stem parts of Cynanchum bungei Decne . The structures of the new glycosides were determined on the basis of spectroscopic analysis, including 1D‐ and 2D‐NMR and HR‐ESI‐MS techniques as well as by comparison of their spectral data with those of related compounds. 相似文献
989.
Interaction of a flexible thioether ligand with mercury(II) acetate and iodide, respectively, yielded two compounds with structural motifs of a macrocycle and a 1D polymer, whose structural patterns were dominated by anions and could be reversibly changed. 相似文献
990.
Heterocoagulation experiments of kaolinite with solvent-diluted-bitumen were carried out to investigate the effect of hydrolyzable metal cations and citric acid on the liberation of bitumen from kaolinite. The adsorption of Ca(2+) and Mg(2+) on kaolinite, and zeta potentials of kaolinite and bitumen droplets in solutions containing 10(-3)mol/L of Ca(2+), Mg(2+) and Fe(3+) with or without citric acid were also measured. It was found that the heterocoagulation of bitumen with kaolinite was enhanced in the presence of the metal cations from pH 7 to pH 10.5, accompanied by a decrease in the magnitude of the zeta potentials and an increase in the adsorption of the metal cations on kaolinite and possibly on bitumen droplets. The addition of 5 x 10(-4)mol/L citric acid reduced the degree of coagulation from 90% to less than 40% in the presence of 10(-3)mol/L Ca(2+) and Mg(2+) cations at pH approximately 10, and at pH approximately 8 for Fe(3+). It was found that hydrolyzable metal cations enhanced bitumen-kaolinite interactions through electrical double layer compression and specific adsorption of the metal hydrolysis species on the surface of kaolinite. The effect of metal cations was removed by citric acid through formation of metal-citrate complexes and/or the adsorption of citrate anions, which restored the zeta potentials of both kaolinite and bitumen. Therefore, electrostatic attraction or repulsion was responsible for the coagulation or dispersion of kaolinite particles from bitumen droplets in the tested system. 相似文献