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991.
Prof. Qingsong Hu Chengkai Zhang Xian Wu Guijie Liang Lei Wang Xiaowei Niu Zhi Wang Wei-Dan Si Yibo Han Ruiqin Huang Prof. Jiawen Xiao Prof. Di Sun 《Angewandte Chemie (International ed. in English)》2023,62(11):e202217784
The low efficiency triplet emission of hybrid copper(I) iodide clusters is a critical obstacle to their further practical optoelectronic application. Herein, we present an efficient hybrid copper(I) iodide cluster emitter (DBA)4Cu4I4 , where the cooperation of excited state structure reorganization and the metallophilicity interaction enables ultra-bright triplet yellow-orange emission with a photoluminescence quantum yield over 94.9 %, and the phonon-assisted de-trapping process of exciton induces the negative thermal quenching effect at 80–300 K. We also investigate the potential of this emitter for X-ray imaging. The (DBA)4Cu4I4 wafer demonstrates a light yield higher than 104 photons MeV−1 and a high spatial resolution of ≈5.0 lp mm−1, showing great potential in practical X-ray imaging applications. Our new copper(I) iodide cluster emitter can serve as a model for investigating the thermodynamic mechanism of photoluminescence in hybrid copper(I) halide phosphorescence materials. 相似文献
992.
993.
This paper examines the initial‐value problem for the nonhomogeneous incompressible nematic liquid crystals system with vacuum. This paper establishes two main results. The first result is involved with the global strong solutions to the 2D liquid crystals system in a bounded smooth domain. Our second result is concerned with the small data global existence result about the 3D system in the whole space. In addition, the local existence and a blow‐up criterion of strong solutions are also mentioned. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
994.
N-(amino-ethyl)-amino-propyl trimethoxy silane (AEAPTMS) is used to modify Fe3O4 with a one-pot coprecipitation method. Powder X-ray diffraction measurements show the spinel structure of magnetite nanoparticles. A high positive charge of +33.96 mV was obtained on the surfaces of modified magnetic nanoparticles, with the diameter ranging from 6.5 to 22.5 nm. The modified Fe3O4 was first applied to the treatment of wastewater from tertiary oil recovery. The obtained results indicated that the oil removal rate increased with the dosage of modified Fe3O4 and slightly increased with the separation time. The mechanism of modified Fe3O4 toward wastewater from tertiary oil recovery was attributed to the electrostatic interaction between negatively charged microemulsion oil in wastewater and the positively charged surfaces of magnetic nanoparticles. 相似文献
995.
996.
Five novel near-infrared electrochromic aromatic polyimides(PIs) with pendent benzimidazole group were synthesized from 4,4'-diamino-4'-(1-benzylbenzimidazol-2-yl)triphenylamine(named as DBBT) with five different dianhydrides via two-step polymerization process, respectively. The maximum UV-Vis absorption bands of these PIs locate at about 335 nm for solid films due to the π-π* transitions. A reversible pair of distinct redox peaks, that were associated with a noticeable color change from original yellow to blue, was observed in the cyclic voltammetry(CV) test. A new absorption peak emerged at 847 nm in near-infrared(NIR) region with increasing voltage in UV-Vis-NIR spectrum, which indicates that PI can be used as NIR electrochromic material. These novel PIs have good electrochemical stability, appropriate energy levels for the highest occupied molecular orbital(HOMO) and the lowest unoccupied molecular orbital(LUMO), in the range of-5.17 e V to-5.20 e V and-2.14 e V to-2.26 e V(versus the vacuum level) determined by cyclic voltammetry method. These values basically consisted with the results of quantum chemical calculation. These polyimides can be used as novel electrochromic and hole transportation materials. 相似文献
997.
Metabolomics method based on ultra high performance liquid chromatography with time‐of‐flight mass spectrometry to analyze toxins in fresh and dried toad venom
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Hongyue Ma Huixia Niu Qin Cao Jing Zhou Yan Gong Zhenhua Zhu Xiang Lv Liuqing Di Dawei Qian Qinan Wu Jin'ao Duan 《Journal of separation science》2016,39(24):4681-4687
Drying is a critical step to prolong the storage time in natural medicine processing but it changes the chemical characteristics of the product. In this study, research was performed to characterize the metabolomic changes in toad venom induced by vacuum‐drying at 60°C and air‐drying at room temperature by ultra high performance liquid chromatography coupled with pattern recognition approaches. In total 52 metabolites, down‐regulated or up‐regulated, were identified as potential chemical markers. Compared with fresh toad venom, vacuum‐drying at 60°C succeeded in raising the conjugated‐type bufadienolide content significantly, while the content of free‐type bufadienolides were slightly reduced. On the other hand, toad venom air‐dried at room temperature presented a relatively low amount of bufadienolides compared with fresh venom. For example, the content of several known anti‐tumor components (gamabufotalin, bufotalin, cinobufagin, etc.) were significantly reduced. The 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide bioassay further showed that venom air‐dried at room temperature had weaker anti‐tumor activity on human hepatocellular carcinoma SMMC‐7721 proliferation in vitro than samples vacuum‐dried at 60°C. These results showed that the great metabolomic changes of toad venom occurred during the drying process, suggesting that a proper drying procedure is important for sustaining the chemical quality of natural medicines. 相似文献
998.
Keto‐benzo[h]‐Coumarin‐Based Near‐Infrared Dyes with Large Stokes Shifts for Bioimaging Applications
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Guangle Niu Prof. Dr. Weimin Liu Prof. Dr. Hongyan Xiao Prof. Dr. Hongyan Zhang Jianhong Chen Qing Dai Prof. Dr. Jiechao Ge Prof. Dr. Jiasheng Wu Prof. Dr. Pengfei Wang 《化学:亚洲杂志》2016,11(4):498-504
Fluorescence imaging is a promising tool for the visualization of biomolecules in living systems and there is great demand for new fluorescent dyes that absorb and emit in the near‐infrared (NIR) region. Herein, we constructed three new fluorescent dyes ( NBC dyes) based on keto‐benzo[h]coumarin ( k‐BC ) and benzopyrilium salts. These dyes showed large Stokes shifts (>100 nm) and NIR emission (>800 nm). The relationship between the structures and optical properties of these dyes was further investigated by using density functional theory calculations at the B3LYP/6‐3G level of theory. Fluorescence images indicated that the fabricated dyes exhibited good photostability and low cytotoxicity and, thus, have potential applications as imaging agents in living cells and animals. 相似文献
999.
Morphology evolution and crystalline structure of controlled‐rheology polypropylene in micro‐injection molding
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Mengjue Li Yang Qi Zhongguo Zhao Zhang Xiang Xia Liao Yanhua Niu Miqiu Kong 《先进技术聚合物》2016,27(4):494-503
In this paper, the microstructural evolution of controlled‐rheology polypropylene (CRPP) with different melt viscoelasticities was investigated by polarized optical microscopy, scanning electronic microscopy, differential scanning calorimeter, and wide‐angle X‐ray diffraction. It is found that a typical “skin‐core” structure formed in CRPP microparts and the thickness of oriented layer of CRPP microparts decreases notably with the addition of peroxide. The thickness of oriented layer and the distribution of different layers strongly depend on the melt flow properties and the corresponding relaxation time (λ). Furthermore, the mechanisms of the suppressed formation of oriented layers during the micro‐injection molding process are discussed mainly from the viewpoint of rheology and thermodynamics. It is revealed that the shear‐induced orientation is one of the key factors for the formation of oriented molecular structure (row nuclei). The final thickness of the oriented layer is the result of the competition between the orientation behavior and the disorientation behavior. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
1000.
High yield synthesis of biodegradable poly(propylene carbonate) from carbon dioxide and propylene oxide
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A novel SalenCoIII (2,4‐dinitrophenoxy) (Salen = N,N'‐bis(3,5‐di‐tert‐butylsalicylidene)‐1,2‐cyclohexanediamino) and 1,10‐phenanthroline monohydrate catalyst system was designed and employed for the copolymerization of CO2 and propylene oxide (PO). The perfectly alternating copolymerization of CO2 and PO proceeds effectively under middle temperature and pressure to yield poly(propylene carbonate) with a high yield and a high number average molecular weight of polymer. The structure of polymer was characterized by the IR and NMR measurements. The perfectly alternating copolymer was confirmed. The MALDI‐TOF spectrum insinuates that the copolymerization of CO2 and PO was initiated by H2O. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献