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991.
Zhou Jiawen Zhu Weiya Zeng Miao Yang Qingqing Li Ping Lan Linfeng Peng Junbiao Li Yuan Huang Fei Cao Yong 《中国科学:化学(英文版)》2019,62(12):1656-1665
Stable radicals are challenging to prepare due to their intrinsic high reactivity. Herein, three trisphenolamine radicals were readily synthesized and exhibited unexpected thermal/electrochemical stability and semiconductor property. These three nitroxide radicals could be considered as a class of aromatized nitro groups or HNO_3 derivatives. The closed-shell nitro-like and open-shell nitroxide resonance structure contribute to their outstanding stability. Furthermore, the tunable ground states, extremely low band gap and p-type charge transport properties were systematically investigated. More importantly, the work presents the concept of aromatic inorganic acid radical(AIAR) and aggregation-induced radical(AIR) mechanism to understand the intrinsic structureproperty relationship of these radicals. In addition, we provide a novel strategy for the design of stable and low bandgap radicals for organic electronics, magnetics, spintronics, etc. 相似文献
992.
<正>Electron transfer (ET) is one of the most fundamental processes in nature, biological systems, and optoelectronic devices. The in-depth ET investigations of synthetic materials are of great significance for the understanding of those occurring in natural systems. Mixed-valence (MV) compounds,consisting of two bridged redox motifs that are structurally identical but different in valence, provide an appealing 相似文献
993.
Xiang‐Lan Chen Jia‐Wei Huang Yi‐Chen Huang Jie Du Yu‐Fei Jiang Yue Zhao Hai‐Bin Zhu 《化学:亚洲杂志》2019,14(7):995-1003
Fe‐Co‐N‐C electrocatalysts have proven superior to their counterparts (e.g. Fe‐N‐C or Co‐N‐C) for the oxygen reduction reaction (ORR). Herein, we report on a unique strategy to prepare Fe‐Co‐N‐C?x (x refers to the pyrolysis temperature) electrocatalysts which involves anion‐exchange of [Fe(CN)6]3? into a cationic CoII‐based metal‐organic framework precursor prior to heat treatment. Fe‐Co‐N‐C‐900 exhibits an optimal ORR catalytic performance in an alkaline electrolyte with an onset potential (Eonset: 0.97 V) and half‐wave potential (E1/2: 0.86 V) comparable to that of commercial Pt/C (Eonset=1.02 V; E1/2=0.88 V), which outperforms the corresponding Co‐N‐C‐900 sample (Eonset=0.92 V; E1/2=0.84 V) derived from the same MOF precursor without anion‐exchange modification. This is the first example of Fe‐Co‐N‐C electrocatalysts fabricated from a cationic CoII‐based MOF precursor that dopes the Fe element via anion‐exchange, and our current work provides a new entrance towards MOF‐derived transition‐metal (e.g. Fe or Co) and nitrogen‐codoped carbon electrocatalysts with excellent ORR activity. 相似文献
994.
Pengfei Zhang Tao Jiang Yuanyuan Li Zheng Zhao Ping Gong Lintao Cai Ryan T. K. Kwok Jacky Wing Yip Lam Xinggui Gu Ben Zhong Tang 《化学:亚洲杂志》2019,14(6):770-774
In this work, we aim to develop cancer cell‐targeting AIE dots based on a polyyne‐bridged red‐emissive AIEgen, 2TPE‐4E, through the combination of metabolic engineering and bio‐orthogonal reactions. Azide groups on a tumor were efficiently produced by intravenous injection of Ac4ManNAz and glycol‐metabolic engineering. These bio‐orthogonal azide groups could facilitate the specific targeting of DBCO‐AIE dots to the tumor cells undergoing metal‐free click reaction in vivo. The efficiency of this targeting strategy could be further improved with the development of new bio‐orthogonal chemical groups with higher reactivity and a large amount of AIEgens could be delivered to the tumor for diagnosis. 相似文献
995.
Nylon 6 and nylon 6,6 reaction equilibria depend in a complex way on water concentration and temperature. For example, data sets from six research groups reveal that the apparent equilibrium constant for polycondensation increases with water at low water concentrations, reaches a maximum, and then decreases as the water concentration rises further. In this article, semi‐empirical expressions are proposed to describe the experimentally observed equilibrium behavior for the five main reactions that occur during nylon 6 and nylon 6,6 polymerization. Nine side reactions involving amidine ends, cyclopentanone ends, and hydrated carboxyl ends are used to develop expressions that account for the influence of both water and temperature on these equilibrium constants. Excellent fit to the data, over the entire range of the available nylon 6 and nylon 6,6 literature data, suggests that the proposed equations will be helpful for modeling reaction equilibria for nylon 6/6,6 copolymerization. 相似文献
996.
Micro and nanomotors (MNMs) are micro/nanoscale devices that are able to convert chemical or external energy into mechanical motion. Based on a multitude of propulsion mechanisms, synthetic MNMs have been developed over the past decades for diverse biomedical applications, particularly drug delivery. Herein, we set out the classification of drugs delivered by MNMs, such as small molecules, nucleic acid, peptides, antibodies, and other proteins, and discuss their current limitations and possibilities in in vivo applications. Challenges and future perspectives are also discussed. With the increasing research enthusiasm in this field and the strengthening of multidisciplinary cooperation, intelligent MNMs will appear in the near future, which will have a profound impact on all related fields. 相似文献
997.
Shih‐Chang Syu Chih‐Hsien Cheng Huai‐Yung Wang Yu‐Chieh Chi Gong‐Ru Lin 《Annalen der Physik》2019,531(2)
The carbon‐rich silicon carbide (C‐rich SixC1?x) micro‐ring channel waveguide with asymmetric core aspect is demonstrated for all‐optical cross‐wavelength pulsed return‐to‐zero on‐off keying (PRZ‐OOK) data conversion. Enhanced nonlinear optical Kerr switching enables 12‐Gbit per second data processing with optimized modulation depth. The inverse tapered waveguide at end‐face further enlarges the edge‐coupling efficiency, and the asymmetric channel waveguide distinguishes the polarization modes. To prevent data shape distortion, the bus/ring gap spacing is adjusted to control the quality factor (Q‐factor) of the micro‐ring. Designing the waveguide cross section at 500 × 350 nm2 provides the C‐rich SixC1?x channel waveguide to induce strong transverse electric mode (TE‐mode) confinement with a large Kerr nonlinearity of 2.44 × 10?12 cm2 W?1. Owing to the trade‐off between the Q‐factor and the on/off extinction ratio, the optimized bus/ring gap spacing of 1400 nm is selected to provide a coupling ratio at 5–6% for compromising the modulation depth and the switching throughput. Such a C‐rich SixC1?x micro‐ring with asymmetric channel waveguide greatly enhances the cross‐wavelength data conversion efficiency to favor its on‐chip all‐optical data processing applications for future optoelectronic interconnect circuits. 相似文献
998.
Li Tao Lai Le-Min Fei Shao-Ming Wang Zhi-Xi 《International Journal of Theoretical Physics》2019,58(12):3973-3985
We study entanglement witness and present a construction of entanglement witnesses in terms of the mutually unbiased measurements (MUMs). These witnesses include the entanglement witnesses constructed from mutually unbiased bases (MUBs) as a special case. Comparing with the dimension dependence of MUBs, the witnesses can be always constructed from a complete set of d + 1 MUMs for any dimension d. We show that our witness can detect entanglement better than previous separability criterion given also by MUMs. And the approach can be experimentally implemented.
相似文献999.
Monogamy and polygamy relations characterize the distributions of entanglement in multipartite systems.We provide classes of monogamy and polygamy inequalities of multiqubit entanglement in terms of concurrence, entanglement of formation, negativity, Tsallis-q entanglement, and Rényi-α entanglement, respectively. We show that these inequalities are tighter than the existing ones for some classes of quantum states. 相似文献
1000.
Peng Fei Ji Yong Li Yue Li Song Feng Qun Zhou Ming Li Tian Shu Qing Yuan 《Physics letters. A》2019,383(26):125841
CdS/Si heterojunctions have been prepared through growing CdS nanocrystallites (nc-CdS) on the silicon nanoporous pillar array (Si-NPA) by the chemical bath deposition method. Cadmium nanocrystallites (nc-Cd) have been observed and ascribed to the reducibility of Si-NPA. The reason for the appearance of CdO is indistinct and the related work will be done in the future. The blue, green and red emissions are ascribed to the silicon oxide layer, band gap of nc-CdS and the sulphur vacancies, respectively. Redshift and blueshift with the annealing temperature about green emissions are contributed to quantum size effect and the structure transition from nc-Cd to CdO. It is beneficial for investigating the structures and defects to the application of CdS/Si in the optoelectronic field. 相似文献