29 results on '"Yanan Li"'
Search Results
2. Ni nanocatalysts supported on MIL-53(Al) for DCPD hydrogenation
- Author
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Yanan Li, Dandan Jia, Zhiping Tao, and Jie Zhao
- Subjects
General Chemical Engineering ,General Chemistry - Abstract
Metal organic frameworks (MOFs) with many unique advantages have drawn wide attention in the field of catalysis. However, the poor structural stability of MOFs limits its application. Heat treatment for MOFs can enhance its electrical conductivity and structural stability, which helps to improve the catalytic performance. Ni nanoparticles supported on MIL-53(Al) were synthesized through different heat treatment temperature. Catalysts with uniform distribution of active nickel and rich mesoporous structure were obtained by adjusting the heat treatment temperature to 500 °C. The results show this catalyst has the best hydrogenation activity and stability. Under the reaction conditions of 60 °C and 2 h, the conversion rate of DCPD is 100%, and the selectivity of
- Published
- 2022
3. Antibacterial activity evaluation and mode of action study of novel thiazole-quinolinium derivatives
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Ying Li, Chen Cuicui, Wei Long, Hooi-Leng Ser, Xuan-He Huang, Ning Sun, Zhihua Liu, Yu-Jing Lu, Zheng Boxin, and Yanan Li
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0303 health sciences ,biology ,010405 organic chemistry ,Chemistry ,General Chemical Engineering ,General Chemistry ,biology.organism_classification ,Antimicrobial ,medicine.disease ,01 natural sciences ,Bacterial cell structure ,Hemolysis ,0104 chemical sciences ,03 medical and health sciences ,Biochemistry ,medicine ,biology.protein ,Antibacterial activity ,Cytotoxicity ,FtsZ ,Mode of action ,Bacteria ,030304 developmental biology - Abstract
New antimicrobial agents are urgently needed to address the emergence of multi-drug resistant organisms, especially those active compounds with new mechanisms of action. Based on the molecular structures of the FtsZ inhibitors reported, a variety of thiazole-quinolinium derivatives with aliphatic amino and/or styrene substituents were synthesized from benzothiazolidine derivatives. In the present study, to further explore the antibacterial potential of thiazole-quinolinium derivatives, several Gram-positive and Gram-negative bacteria were treated with the newly modified compounds and the biological effects were studied in detail in order to understand the bactericidal action of the compounds. Our findings reveal that some of these derivatives possess good potent bactericidal activity as they can inhibit Gram-positive methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus and also some Gram-negative organisms and NDM-1 Escherichia coli. Furthermore, compounds 4a1–4a4 and 4b1–4b4 altered the morphology of bacterial cells and the cells displayed a more-elongated shape compared to the untreated cells. Biochemical assays showed that 4a4 and 4b4 stimulate FtsZ polymerization in bacterial cells, which eventually disrupts its dynamic assembly and Z-ring formation. The inhibition of this crucial step in bacterial cell division could potentially represent their main mechanism of antibacterial activity. Cytotoxicity assay and hemolysis assay suggested that 4a4 and 4b4 possess low cytotoxicity. In summary, these results further highlight the importance of 4a4 and 4b4 that could be developed as potent and effective bacteriostatic agents against multi-drug resistant bacteria.
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- 2020
4. Antibacterial activity and mechanism of action of a thiophenyl substituted pyrimidine derivative
- Author
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Wing-Leung Wong, Zhiyuan Fang, Xiaomei Li, Yu-Jing Lu, Siu-Cheong Yan, Zheng Yuanyuan, Kin-Fai Chan, Ning Sun, Yanan Li, and Kwok Yin Wong
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biology ,Chemistry ,medicine.drug_class ,General Chemical Engineering ,Antibiotics ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,biology.organism_classification ,01 natural sciences ,Bacterial cell structure ,0104 chemical sciences ,Microbiology ,Antibiotic resistance ,Mechanism of action ,biology.protein ,medicine ,medicine.symptom ,0210 nano-technology ,Antibacterial activity ,FtsZ ,Bacteria ,Antibacterial agent - Abstract
The issue of multidrug resistant bacteria is a worldwide health threat. To develop new antibacterial agents with new mechanisms of action is thus an urgent request to address this antibiotic resistance crisis. In the present study, a new thiophenyl-pyrimidine derivative was prepared and utilized as an effective antibacterial agent against Gram-positive strains. In the tests against MRSA and VREs, the compound showed higher antibacterial potency than that of vancomycin and methicillin. The mode of action is probably attributed to the effective inhibition of FtsZ polymerization, GTPase activity, and bacterial cell division, which cause bactericidal effects. The compound could be a potential candidate for further development as an effective antibiotic to combat drug-resistant bacteria.
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- 2019
5. A ratiometric fluorescent probe for the detection of β-galactosidase and its application
- Author
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Bing Deng, Shaoxiang Yang, Haitao Chen, Baoguo Sun, and Yanan Li
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Detection limit ,Chromatography ,Chemistry ,General Chemical Engineering ,02 engineering and technology ,General Chemistry ,Luminous intensity ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Fluorescence ,0104 chemical sciences ,Naked eye ,0210 nano-technology - Abstract
Herein, a coumarin fluorescent probe (Probe 1) was developed for the ratiometric detection of β-galactosidase (β-gal) activity. The detection range was 0–0.1 U mL−1 and 0.2–0.8 U mL−1, and the limit of detection (LOD) was 0.0054 U mL−1. Moreover, the luminous intensity of Probe 1 increased gradually with increase in β-gal activity. It could be observed under 254 nm UV irradiation by the naked eye. Furthermore, this method only required a small amount of sample (20 μL) and a short analytical time (30 min) for the detection of β-gal activity with a low LOD. Probe 1 was successfully used to detect β-gal activity in real fruit samples, and can be applied to the quantitative and qualitative detection of β-gal activity.
- Published
- 2021
6. Novel catenated N6energetic compounds based on substituted 1,2,4-triazoles: synthesis, structures and properties
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Chen Tao, Chang Pei, Hu Jianjian, Bozhou Wang, Yanan Li, Yinglei Wang, and Wang Bin
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Materials science ,General Chemical Engineering ,Detonation ,Infrared spectroscopy ,02 engineering and technology ,General Chemistry ,Crystal structure ,Conjugated system ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Standard enthalpy of formation ,0104 chemical sciences ,Differential scanning calorimetry ,Elemental analysis ,Mass spectrum ,Physical chemistry ,0210 nano-technology - Abstract
1-Amino-3,5-dinitro-1,2,4-triazole (ADNT) was prepared using an efficient N-amination process. Three novel catenated N6 energetic derivatives of ADNT, which contain 1,1′-azobis(3,5-dinitro-1,2,4-triazole) (ABDNT), 1,1′-azobis(3-chloro-5-nitro-1,2,4-triazole) (ABCNT) and 1,1′-azobis(3,5-diazido-1,2,4-triazole) (ABDAT), were synthesized from N-amino oxidative-coupling reactions of ADNT. All compounds were fully characterized by 1H and 13C nuclear magnetic resonance spectroscopies, infrared spectroscopy, elemental analysis, mass spectrum, as well as differential scanning calorimetry (DSC). The crystal structure of compound ABCNT was confirmed by single-crystal X-ray diffraction showing an extensive conjugated structure. The densities of energetic derivatives ranged from 1.71 to 1.93 g cm−3, and all compounds have positive heats of formation in the range of 774.8 to 2150.8 kJ mol−1. Based on the measured densities and calculated heats of formation, theoretical performance calculations, including detonation pressures (29.6–42.4 GPa) and detonation velocities (8.22–9.49 km s−1) were carried out using the Gaussian 09 program and Kamlet–Jacobs equations, and they compared favorably with those of TNT and RDX. These properties make them potentially competitive as new high energy-density compounds.
- Published
- 2018
7. AgBr/g-C3N4nanocomposites for enhanced visible-light-driven photocatalytic inactivation ofEscherichia coli
- Author
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Shuanglong Ma, Yanan Li, Pengfei Wang, Sihui Zhan, Yi Li, Haitao Wang, and Qianlei Hou
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Materials science ,Quenching (fluorescence) ,Scanning electron microscope ,General Chemical Engineering ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,X-ray photoelectron spectroscopy ,Transmission electron microscopy ,Photocatalysis ,0210 nano-technology ,Spectroscopy ,High-resolution transmission electron microscopy ,Visible spectrum - Abstract
Visible-light-driven photocatalytic disinfection is highly desired for water treatment due to its advantages such as wide applicability and being free of disinfection byproducts. In this study, AgBr/g-C3N4 hybrid nanocomposites were evaluated as photocatalysts under visible light irradiation for water disinfection using Escherichia coli as a model pathogen. The physicochemical and photo-electrochemical properties of the photocatalyst were systematically characterized using advanced techniques including scanning electron microscopy (SEM), transmission electron microscopy (HRTEM), powder X-ray diffraction (XRD), UV-visible diffuse reflectance spectra (DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectra and electron spin resonance (ESR) spectroscopy. The inactivation mechanism of E. coli was systematically investigated by monitoring the morphology change of the bacteria and analyzing the role of reactive species. The optimized AgBr/g-C3N4 hybrid photocatalyst exhibited remarkably enhanced visible-light-driven photocatalytic disinfection performance towards E. coli over that of pure g-C3N4 and AgBr under visible light, which could completely inactivate 107 cfu mL−1 E. coli in 90 min. Quenching studies indicated that h+ is the main reactive species responsible for inactivating E. coli. The mechanism study revealed a Z-scheme charge transfer mechanism between AgBr and g-C3N4. The g-C3N4 could effectively trap the photogenerated conduction band electrons of AgBr via a Z-scheme type of route, thus significantly promoting the electron–hole separation. The trapping of electrons by g-C3N4 could facilitate h+ accumulation, which accounts for the better disinfection performance of AgBr/g-C3N4 compared to AgBr and g-C3N4.
- Published
- 2018
8. Complex formation constant of ferric ion with Gly, Pro-Hyp and Gly-Pro-Hyp
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Guangrong Huang, Shella Permatasari Santoso, Fangyuan Chen, Mingyu Zhi, and Yanan Li
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chemistry.chemical_classification ,Base (chemistry) ,010405 organic chemistry ,Chemistry ,General Chemical Engineering ,Potentiometric titration ,02 engineering and technology ,General Chemistry ,01 natural sciences ,0104 chemical sciences ,Metal ,020401 chemical engineering ,Ionic strength ,visual_art ,Glycine ,medicine ,visual_art.visual_art_medium ,Ferric ,Chelation ,0204 chemical engineering ,Iron deficiency (plant disorder) ,medicine.drug ,Nuclear chemistry - Abstract
The complexes of protein hydrolysates with iron ions may provide one solution for treating iron deficiency because they can work as iron absorption promoters. The chelating ability of some protein hydrolyzates is the key for their iron absorption promotion. Collagen is the most abundant protein in the nature, and collagen peptides are reported to have the ability to promote iron absorption. Collagen's basic tri-peptide unit, i.e., glycine–proline–hydroxyproline (Gly-Pro-Hyp) and its digestion products, glycine (Gly) and proline–hydroxyproline (Pro-Hyp), have been studied against the ferric metal ion. The complexation abilities were determined potentiometrically at three different temperatures of 25 °C, 37 °C, and 40 °C. The ionic strength was maintained using 0.15 mol dm−3 NaCl. Potentiometric data were refined using Hyperquad 2008, and the species distributions were simulated using HySS2009. The complexes of [MAxHy], with x = 1 to 3 and y = −4 to 2, were refined from three ligands at different temperatures and in the pH range from 2 to 11. The complex formation constant (log β) indicated that the complex of Gly-Pro-Hyp was the most stable followed by Pro-Hyp and Gly complexes. Thermodynamic analysis revealed that the formation of the complexes of [MAxHy], with x = 1 to 3 and y = 0, was spontaneous since the ΔG value was negative; this means that Gly, Pro-Hyp and Gly-Pro-Hyp have good iron chelating abilities and therefore, they can act as promising iron absorption promoters. The thermodynamic properties of these complexes were also studied, and the base for the usage of these complexes was provided.
- Published
- 2018
9. Synthesis of 1,3-dicarbonyl-functionalized reduced graphene oxide/MnO2 composites and their electrochemical properties as supercapacitors
- Author
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Chaoke Bulin, Ruihong Li, Qiwei Zhang, Bangwen Zhang, Ruiguang Xing, Xin Ge, He Sun, and Yanan Li
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Supercapacitor ,Materials science ,Scanning electron microscope ,Graphene ,General Chemical Engineering ,Oxide ,Nanoparticle ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Microstructure ,01 natural sciences ,0104 chemical sciences ,law.invention ,symbols.namesake ,chemistry.chemical_compound ,X-ray photoelectron spectroscopy ,chemistry ,law ,symbols ,Composite material ,0210 nano-technology ,Raman spectroscopy - Abstract
A novel 1,3-dicarbonyl-functionalized reduced graphene oxide (rDGO) was prepared by N-(4-aminophenyl)-3-oxobutanamide interacting with the epoxy and carboxyl groups of graphene oxide. The high-performance composite supercapacitor electrode material based on MnO2 nanoparticles deposited onto the rDGO sheet (DGM) was fabricated by a hydrothermal method. The morphology and microstructure of the composites were characterized by field-emission scanning electron microscopy, transmission electron microscopy, Raman microscopy and X-ray photoelectron spectroscopy. The obtained results indicated that MnO2 was successfully deposited on rDGO surfaces. The formed composite electrode materials exhibit excellent electrochemical properties. A specific capacitance of 267.4 F g−1 was obtained at a current density of 0.5 A g−1 in 1 mol L−1 H2SO4, while maintaining high cycling stability with 97.7% of its initial capacitance after 1000 cycles at a current density of 3 A g−1. These encouraging results are useful for potential energy storage device applications in high-performance supercapacitors.
- Published
- 2018
10. Modified carbon felt made using CexA1−xO2 composites as a cathode in electro-Fenton system to degrade ciprofloxacin
- Author
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Yi Li, Xinqiang Mi, Xueyue Mi, Yanan Li, Suge Zhang, Jingjing Han, and Sihui Zhan
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Materials science ,Chemical substance ,General Chemical Engineering ,Metallurgy ,Composite number ,02 engineering and technology ,General Chemistry ,010501 environmental sciences ,021001 nanoscience & nanotechnology ,01 natural sciences ,Mineralization (biology) ,Cathode ,law.invention ,Magazine ,X-ray photoelectron spectroscopy ,law ,Degradation (geology) ,0210 nano-technology ,Science, technology and society ,0105 earth and related environmental sciences ,Nuclear chemistry - Abstract
Carbon felt (CF) was modified by CexA1−xO2 (A = Zr, Cu and Ni) and the role of these CexA1−xO2/CF (A = Zr, Cu and Ni) cathode materials in the oxidative degradation of antibiotic ciprofloxacin (CIP) was investigated in the electro-Fenton system. SEM, BET, TEM, XPS, TOC, HPLC-MS, CV and EIS were used to understand the characteristics of these cathode materials. The CIP degradation efficiency of the CexA1−xO2/CF (A = Zr, Cu and Ni) cathode was better than that of pure CF, and 2.0 wt% Ce0.75Zr0.25O2/CF was the most effective cathode material for degradation of CIP. It reached 100% degradation efficiency of CIP after 1 h and almost total mineralization (97.45%) after 6 h, owing to synergistic effects from the predominant role of homogeneous ˙OH produced electrocatalytically through the Fenton reaction of Fe2+ and H2O2 and heterogeneous ˙OH produced via the Fenton-like reaction of Ce3+ and H2O2 and the electrocatalytic activity of Ce0.75Zr0.25O2 composite and the strong electrosorption of carbon felt. A possible path of CIP degradation was proposed in the paper.
- Published
- 2017
11. Effect of electron beam irradiation on the structural characteristics and functional properties of rice proteins
- Author
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Yanan Li, Li Wang, Zhengxing Chen, Xiaohu Luo, Yongfu Li, and Xinxia Zhang
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Conformational change ,Chemistry ,General Chemical Engineering ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,Electron beam irradiation ,Uv visible spectra ,Adsorption ,Emulsion ,Irradiation ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Protein secondary structure - Abstract
A study of the structural and functional changes of rice proteins (RPs) induced by electron beam irradiation (EBI) at 5 kGy, 10 kGy, 20 kGy, and 30 kGy was performed. The microcosmic surface structures of the RPs were changed and fragmented due to irradiation damage occurring on the RP surfaces. The changes in the UV visible spectra, intrinsic fluorescence spectra, surface hydrophobicity and SH and SS group contents indicated that the RPs unfolded after EBI treatment. In addition, the degree of conformational change was increased with increasing EBI treatment doses. FTIR analysis showed that the secondary structure redistributed, showing decreases in α-helices and concomitant increases in β-sheets, β-turns and random coils. The functional properties, emulsifying abilities, water adsorption capacities and oil adsorption capacities of the irradiated RPs improved dose-dependently, with maximums occurring at 30 kGy. The foaming properties were also enhanced by EBI; however, this effect was not dose-dependent. In contrast, all of the samples irradiated by electron beams presented lower emulsion stability than the control (0 kGy). These results provide a theoretical basis for the application of EBI in improving protein properties in the future.
- Published
- 2018
12. Synthesis, structure and properties of neutral energetic materials based on N-functionalization of 3,6-dinitropyrazolo[4,3-c]pyrazole
- Author
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Yanan Li, Lianjie Zhai, Bozhou Wang, Shengyong Zhang, and Yuanjie Shu
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General Chemical Engineering ,Infrared spectroscopy ,02 engineering and technology ,General Chemistry ,Nuclear magnetic resonance spectroscopy ,Crystal structure ,Pyrazole ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Standard enthalpy of formation ,0104 chemical sciences ,chemistry.chemical_compound ,Differential scanning calorimetry ,chemistry ,Computational chemistry ,Elemental analysis ,Physical chemistry ,0210 nano-technology ,Imide - Abstract
3,6-Dinitropyrazolo[4,3-c]pyrazole (DNPP, 4) was prepared using an efficient modification process. Various neutral energetic derivatives of DNPP were synthesized from N-functionalization of imide (NH) group. All compounds were fully characterized by 1H and 13C nuclear magnetic resonance spectroscopy, infrared spectroscopy, elemental analysis, and differential scanning calorimetry (DSC). The crystal structures of compounds 4·2H2O, 12 and 15 were confirmed by single-crystal X-ray diffraction, showing extensive hydrogen-bonding. The densities of neutral derivatives ranged from 1.74 to 1.95 g cm−3, and all compounds have positive heats of formation in the range of 18.8 to 863 kJ mol−1. Based on the measured densities and calculated heats of formation, theoretical performance calculations, including detonation pressures (27.1–41.5 GPa) and velocities (7819–9364 m s−1), were carried out using the Gaussian 09 program and Kamlet–Jacobs equations, and they compare favorably with those of TNT and RDX. These properties make them potential and competitive for use as new high energy-density materials.
- Published
- 2016
13. One-pot synthesis and characterization of tungsten-containing meso-ceria with enhanced heterogenous oxidative desulfurization in fuels
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Meng Li, Wenshuai Zhu, Yanchen Wei, Yanan Li, Huaming Li, Qi Zhang, Ming Zhang, and Jun Xiong
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Materials science ,General Chemical Engineering ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Tungsten ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,Flue-gas desulfurization ,Catalysis ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,law ,Dibenzothiophene ,Ionic liquid ,Calcination ,0210 nano-technology ,Mesoporous material ,Hybrid material - Abstract
A series of hybrid materials tungsten-containing meso-ceria characterized in detail have been designed from polyoxometalates-based ionic liquids using a one-pot hydrothermal and calcination method for heterogenous oxidative desulfurization. The experimental results indicated that the as-prepared catalysts possessed mesoporous structures and the tungsten species were well dispersed in the ceria. The effect of calcination temperature and tungsten content on the hybrid materials during the removal of dibenzothiophene was also investigated. Based on the experimental results, the optimal molar ratio of tungsten/ceria and calcination temperature of the hybrid materials were 0.25 and 400 °C, respectively, wherein the catalytic performance could reach 99.2% under mild conditions. It is also found that the catalyst could remove other sulfur-containing compounds in the order of DBT > BT > 4,6-DMDBT.
- Published
- 2016
14. Facile synthesis of nitrogen-doped carbon dots with robust fluorescence in a strongly alkaline solution and a reversible fluorescence ‘off–on’ switch between strongly acidic and alkaline solutions
- Author
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Ruiping Deng, Yingbo Liu, Liang Zhou, Hongjie Zhang, and Yanan Li
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Chemistry ,General Chemical Engineering ,Simulated body fluid ,Inorganic chemistry ,Quantum yield ,chemistry.chemical_element ,Protonation ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Fluorescence ,0104 chemical sciences ,chemistry.chemical_compound ,Ammonium hydroxide ,Deprotonation ,0210 nano-technology ,Citric acid ,Carbon - Abstract
In this study, hydrophilic nitrogen-doped carbon dots (N-CDs) have been hydrothermally prepared using citric acid and various concentrations of ammonium hydroxide. The N-CDs exhibit an excitation-independent blue emission and an optimal quantum yield of 24.2%. Under strongly alkaline conditions adjusted by various alkaline solutions, the N-CDs exhibit robust fluorescence performance, even at an extreme pH value of 13. Although the fluorescence is quenched in strongly acidic solutions (pH = 1), the N-CDs exhibit reversible and repeatable ‘off–on’ fluorescence on modulating the pH value between 1 and 13, resulting from the protonation and deprotonation of the fluorescence-related surface states. Moreover, the N-CDs maintain a bright and stable emission in simulated body fluid (SBF). Thus, the N-CDs have promising applications for dynamic detection of pH switching caused by strongly acidic and strongly alkaline conditions and fluorescence bio-imaging of living organisms even under extreme pH conditions.
- Published
- 2016
15. Green organic light-emitting devices with external quantum efficiency up to nearly 30% based on an iridium complex with a tetraphenylimidodiphosphinate ligand
- Author
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Hongjie Zhang, Yunlong Jiang, Yanan Li, Liang Zhou, Xuesen Zhao, Rongzhen Cui, Jing-Lin Zuo, and You-Xuan Zheng
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Brightness ,Materials science ,Ligand ,business.industry ,General Chemical Engineering ,Doping ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Electroluminescence ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Triphenylamine ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Optoelectronics ,Quantum efficiency ,Iridium ,0210 nano-technology ,business ,Electrical efficiency - Abstract
In this work, a series of electroluminescent (EL) devices with single- or double-light-emitting layer(s) (EML) were fabricated to further improve the EL performances of green iridium complex (tfmppy)2Ir(tpip) (tfmppy = 4-trifluoromethylphenylpyridine, tpip = tetraphenylimido-diphosphinate). p-Type material 4,4′,4′′-tri-s(carbazole-9-yl)triphenylamine and bipolar material 2,6-bis(3-(9H-carbazol-9-yl)phenyl)pyridine were chosen as host materials of EML1 and EML2, respectively. Experimental results displayed that not only the doping concentration but also the thicknesses of EML and the electron transport layer strongly influence device performances. Finally, a high performance green EL device with maximum brightness, current efficiency, power efficiency and external quantum efficiency (EQE) up to 113 610 cd m−2, 112.30 cd A−1, 97.95 lm W−1 and 29.4%, was realized. Even at the practical brightness of 1000 cd m−2, current efficiency as high as 107.6 cd A−1 (EQE = 28.1%) can still be retained by the same device. To our best knowledge, EL performances of this device were amongst the highest results of the previously reported green devices.
- Published
- 2016
16. High performance red organic electroluminescent devices based on a trivalent iridium complex with stepwise energy levels
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Liang Zhou, Rongzhen Cui, Yingjie Cui, Yunlong Jiang, Hongjie Zhang, Xuesen Zhao, Qi Zhu, Yanan Li, and Weiqiang Liu
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business.industry ,Chemistry ,General Chemical Engineering ,Doping ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Electroluminescence ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Triphenylamine ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Quinoxaline ,Pyridine ,Optoelectronics ,Molecule ,Quantum efficiency ,Iridium ,0210 nano-technology ,business - Abstract
In this work, electroluminescent (EL) devices with double light-emitting layers (EMLs) having stepwise energy levels were designed and fabricated to improve the EL performances of the red light-emitting trivalent iridium complex bis(2-methyldibenzo[f,h]quinoxaline)(acetylacetonate)iridium(III) [Ir(MDQ)2(acac)]. To broaden the recombination zone and facilitate the balance of carriers on emitter molecules, the widely used p-type material 4,4′,4′′-tri(N-carbazolyl)triphenylamine (TcTa) and bipolar material 2,6-bis(3-(9H-carbazol-9-yl)phenyl)pyridine (26DCzPPy) were chosen as host materials of EML1 and EML2, respectively due to their well matched energy levels. Interestingly, slight decomposition of Ir(MDQ)2(acac) molecules was observed during the deposition of EML, which causes the rapidly decreased brightness at relatively high doping concentration. Finally, a high performance red EL device with maximum current efficiency of 44.76 cd A−1, power efficiency of 40.19 lm W−1, and external quantum efficiency (EQE) of 15.5% was obtained by optimizing the doping concentration of Ir(MDQ)2(acac). Even at a high brightness of 1000 cd m−2 (5.2 V), a current efficiency as high as 40.59 cd A−1 (EQE = 14.4%) can still be retained by the same device.
- Published
- 2016
17. pH-Responsive nano sensing valve with self-monitoring state property based on hydrophobicity switching
- Author
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Yongqiang Wen, Xiangyu Jiao, Xueji Zhang, Yanlin Song, Fengyu Li, Wenqian Wang, and Yanan Li
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Materials science ,General Chemical Engineering ,technology, industry, and agriculture ,Nanotechnology ,Protonation ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Deprotonation ,Nano ,Molecular Transport ,Naked eye ,0210 nano-technology ,Mesoporous material ,Porous medium ,Photonic crystal - Abstract
Nano valves have been used in functional porous materials to control molecular transport by changing their properties in response to external stimuli. But most of them are limited by the blocking units and cannot show their state by themselves. Herein, pH switchable nano valves were constructed using mesoporous inverse opal photonic crystal, which realized free-blockage nano valves and achieved the monitoring of the state of the valve by the naked eye without an external indicator. The nano valves were modified by phenylamine groups, which has a convertible hydrophobic/hydrophilic property between deprotonation and protonation. The valves were hydrophobic enough to prevent solution passing through at pH 7.0, and meanwhile a green color was presented. With the decrease of the pH value of the solution, the valves became open and presented a yellow to red color because of the protonation of phenylamine groups followed by the invasion of solution. Thus, in this study not only a free-blockage valve but also nano sensing valve was constructed. We believe that our studies provide new insights into photonic crystal sensors and nano sensing valve.
- Published
- 2016
18. AgBr/g-C
- Author
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Sihui, Zhan, Qianlei, Hou, Yi, Li, Shuanglong, Ma, Pengfei, Wang, Yanan, Li, and Haitao, Wang
- Abstract
Visible-light-driven photocatalytic disinfection is highly desired for water treatment due to its advantages such as wide applicability and being free of disinfection byproducts. In this study, AgBr/g-C
- Published
- 2018
19. Synthesis of 1,3-dicarbonyl-functionalized reduced graphene oxide/MnO
- Author
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Ruiguang, Xing, Ruihong, Li, Xin, Ge, Qiwei, Zhang, Bangwen, Zhang, Chaoke, Bulin, He, Sun, and Yanan, Li
- Abstract
A novel 1,3-dicarbonyl-functionalized reduced graphene oxide (rDGO) was prepared by
- Published
- 2017
20. Bio-inspired double-layer structure artificial microreactor with highly efficient light harvesting for photocatalysts
- Author
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Yanlin Song, Mingzhu Li, Jue Hou, Jian Liu, Qiang Yang, Yanan Li, and Huizeng Li
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Double layer (biology) ,Materials science ,General Chemical Engineering ,Spongy tissue ,Photocatalysis ,Nanotechnology ,General Chemistry ,Microreactor ,Light scattering ,Nanocrystalline material - Abstract
Submerged aquatic leaf structures with two layers of epidermis tissue for light focusing and trapping, and spongy tissue for light scattering were introduced as templates to fabricate photocatalysts. The artificial TiO2 leaf microreactors showed better photocatalytic efficiency than aquatic leaf with three layers structures, over 7 times larger than that of nanocrystalline of TiO2.
- Published
- 2015
21. A green high-initiation-power primary explosive: synthesis, 3D structure and energetic properties of dipotassium 3,4-bis(3-dinitromethylfurazan-4-oxy)furazan
- Author
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Yanan Li, Bi Fuqiang, Xuezhong Fan, Bozhou Wang, Yanlong Zhu, and Lianjie Zhai
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Explosive material ,Exothermic process ,General Chemical Engineering ,Detonation velocity ,Detonation ,Infrared spectroscopy ,General Chemistry ,Furazan ,Standard enthalpy of formation ,chemistry.chemical_compound ,chemistry ,Physical chemistry ,Organic chemistry ,Single crystal - Abstract
A new green primary explosive, dipotassium 3,4-bis(3-dinitromethylfurazan-4-oxy)furazan (K2BDFOF), was synthesized via a four-step procedure including cyano addition, diazotization, N2O5 nitration, and KI reduction. The compound was characterized by multinuclear NMR spectroscopy, IR spectroscopy, elemental analysis, DSC, TG/DTG as well as single crystal X-ray diffraction. X-ray diffraction studies reveal an intriguing 3D framework structure. The central K ions are linked by dinitromethanide anions to give a 1D spiral chain with parallelogram-like repeat units, and these 1D chains are further linked by one oxygen atom in the nitro group coordinated with a K ion to form a two-dimensional wave-like layer structure. Additionally the kinetic parameters of the exothermic process for K2BDFOF were studied by Kissinger's and Ozawa–Doyle's methods. The sensitivities were determined by standardised impact and friction tests, and the heat of formation was calculated with the atomization method at the CBS-4M level of theory. With the heat of formation (−8.4 kJ mol−1) and the room-temperature X-ray density (2.09 g cm−3), impressive values for the detonation parameters such as detonation velocity (8431 m s−1) and pressure (329 kbar) were computed using the EXPLO5 program and compared to the most commonly used primary explosive, lead azide, as well as the recently published dipotassium 1,1′-dinitramino-5,5′-bistetrazolate.
- Published
- 2015
22. Synthesis, characterization and properties of heat-resistant explosive materials: polynitroaromatic substituted difurazano[3,4-b:3′,4′-e]pyrazines
- Author
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Lianjie Zhai, Bozhou Wang, Hui Li, Ning Liu, Yuanjie Shu, and Yanan Li
- Subjects
Explosive material ,Pyrazine ,Chemistry ,Hydrogen bond ,General Chemical Engineering ,General Chemistry ,Carbon-13 NMR ,chemistry.chemical_compound ,Differential scanning calorimetry ,Elemental analysis ,Proton NMR ,Physical chemistry ,Organic chemistry ,Thermal stability - Abstract
The synthesis of three heat-resistant explosive materials: 4,8-di(2,4,6-trinitrophenyl)difurazano[3,4-b:3′,4′-e]pyrazine (1), 4,8-di(2,4-dinitrophenyl)difurazano[3,4-b:3′,4′-e]pyrazine (2), 4-amino-8-(2,4,6-trinitrophenyl)difurazano[3,4-b:3′,4′-e]pyrazine (3),were reported and characterized by 1H NMR,13C NMR, IR as well as elemental analysis. X-ray crystallographic analysis confirmed the structure of 2, as well as displaying intermolecular hydrogen bonding. The thermal behaviors of these compounds were studied with differential scanning calorimetry (DSC) and thermal gravity-differential thermal gravity analysis (TG-DTG) methods. All the compounds showed good thermal stability with exothermic decomposition peaks in the range of 283 °C to 415 °C, on DSC. The sensitivities and calculated explosive performances were also reported for these energetic materials. All the results showed that polynitroaromatic substituted difurazano[3,4-b:3′,4′-e]pyrazines have the potential to be useful heat-resistant explosive materials.
- Published
- 2015
23. Preparation of monodispersed CuS nanocrystals in an oleic acid/paraffin system
- Author
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Yanan Li, Fei Xie, Xiaojiang Li, Wei Li, Minfang Chen, Yue Zhao, and Wenjiang Li
- Subjects
Materials science ,Photoluminescence ,Band gap ,General Chemical Engineering ,Liquid paraffin ,Inorganic chemistry ,Oxide ,General Chemistry ,chemistry.chemical_compound ,Nanocrystal ,X-ray photoelectron spectroscopy ,chemistry ,Chemical engineering ,Transmission electron microscopy ,Absorption (chemistry) - Abstract
Well-dispersed CuS nanocrystals were synthesized through a simple hot injection approach using cupric oxide and elemental sulfur as the precursors in an oleic acid/liquid paraffin system. The structural, morphological and optical properties of the as-prepared nanocrystal CuS samples were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet-visible and near-infrared spectrophotometry, and room-temperature photoluminescence (RT-PL). The band gap of the CuS samples were estimated from the ultraviolet-visible spectra. The formation mechanism of monodispersed CuS nanocrystals in an oleic acid/liquid paraffin system was proposed. The cleaning agents have an important influence on the final morphology of the CuS nanocrystals, and pure hexagonal covellite CuS NCs can be obtained by controlling the ratio of Cu2+ : S2− = 1 : 1. The as-prepared CuS nanocrystals with the narrow band gap reveal dramatically broad absorption bands in the visible-light and near-infrared (NIR) region, exhibiting promising applications in photovoltaic cells, electrochemical sensors and photocatalysts.
- Published
- 2015
24. Co-delivery of siRNA and paclitaxel into cancer cells by hyaluronic acid modified redox-sensitive disulfide-crosslinked PLGA–PEI nanoparticles
- Author
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Buhai Wang, Yanan Li, Ouahab Ammar, Jue Wang, Yu Tian, Chunmeng Sun, Yan Shen, Jiasheng Tu, and Huimin Sun
- Subjects
Biodistribution ,Small interfering RNA ,Chemistry ,General Chemical Engineering ,technology, industry, and agriculture ,General Chemistry ,Transfection ,Molecular biology ,PLGA ,chemistry.chemical_compound ,Paclitaxel ,In vivo ,Drug delivery ,Cancer cell - Abstract
The main objective of our research was established in order to put forward a targeted anticancer co-delivery system for both micro-molecular chemotherapeutic drugs and small interfering RNA (siRNA). The drug delivery system can efficiently combine the advantages of the two therapeutic strategies with different mechanisms via their synergetic effects for cancer therapy. In this study, a cooperative nano-platform of docetaxel (DTX) and specific silencer select siRNA was developed by suppressing the cyclooxygenase-2 (COX-2) gene expression within one single nano-particle (NP) composed of poly(D,L-lactide-co-glycolide) (PLGA) bearing disulfide-linked reducible polyethyleneimine (PEIss) covered by hyaluronic acid (HA). PEIss was successfully synthesized by Michael addition of low molecular weight PEI (Mw = 1800 Da) with cystaminebisacrylamide (CBA). Docetaxel (DTX) was entrapped in the hydrophobic PLGA core, whereas negatively charged siRNA was adsorbed on the cationic shell of PEIss by electrostatic attraction. The redundant positive charge of PEIss allowed the introduction of HA onto the nanoparticles as active targeting groups. The whole complex was then delivered to both sensitive and resistant SGC-7901 gastric cancer cells that over-express CD44 receptors. This novel system was designated as HRPSP NPs (HA–PEIss–PLGA nanoparticles). HA–PEI–PLGA nanoparticles (HPP NPs) were also prepared to make a comparison. The electrophoresis confirmed the good stability of siRNA/HRPSP complex in the presence of PBS (pH 7.4), competitive heparin and RNase and remarkable sensitivity and reducibility to GSH. In in vitro cell transfection, siRNA/HRPSP complexes performed with higher transfection efficiency than siRNA/HPP and siRNA/RPSP and siRNA/PP complexes preferentially through caveolae-mediated endocytosis, which might be a desirable pathway to avoid the lysosomal degradation of delivered genes. Q-PCR and Western Blot experiments proved that COX-2 mRNA and COX-2 protein expressions were reduced to a statistically significant level in comparison with the control and the scrambled HRPSP/siRNA complex after treatment with the NPs/siRNA complex. In vivo, Dir/HRPSP/siRNA NPs complexes exhibited higher intensity at the tumor tissue compared to the non HA modified complexes. The biodistribution results demonstrated that DTX/HRPSP NPs could reduce DTX uptake particularly by the liver and lungs to limit the side effects while significantly increasing DTX accumulation in the tumors. Above these, HRPSP NPs were highly promising nano-carriers for the combinatorial delivery of siRNA and lipophilic anti-cancer drugs.
- Published
- 2015
25. One-pot synthesis of ordered mesoporous silica encapsulated polyoxometalate-based ionic liquids induced efficient desulfurization of organosulfur in fuel
- Author
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Wenshuai Zhu, Huaming Li, Meng Li, Yanan Li, Hongping Li, Ming Zhang, Qi Chen, and Sheng Yin
- Subjects
Materials science ,General Chemical Engineering ,Inorganic chemistry ,General Chemistry ,Mesoporous silica ,Catalysis ,chemistry.chemical_compound ,chemistry ,X-ray photoelectron spectroscopy ,Specific surface area ,Ionic liquid ,Polyoxometalate ,Hybrid material ,Organosulfur compounds - Abstract
In this work, a novel hybrid material of an ordered mesoporous silica (OMS) encapsulated polyoxometalate-based ionic liquid [C4mim]3PW12O40 (C4-IL) was successfully fabricated through a one-pot hydrothermal process, and firstly employed in the oxidative desulfurization of organosulfur. The as-prepared material OMS encapsulated C4-IL (C4-IL@OMS) was systematically characterized by Fourier transform infrared, Raman, X-ray diffraction, X-ray photoelectron spectroscopy, nitrogen absorption–desorption isotherms, scanning electron microscopy and transmission electron microscopy. The designed material exhibited robust activity for removing sulfur-containing compounds under mild conditions due to the high dispersion of C4-IL in OMS and lager specific surface area of the catalyst. 31P nuclear magnetic resonance and ultraviolet-visible spectrum were employed to evaluate the stability of the catalyst after the reaction. Additionally, the sulfur removal of the hybrid material C4-IL@OMS could still reach 93% after recycling seven times without obvious decrease in activity.
- Published
- 2015
26. The preparation and catalytic performance of graphene-reinforced ion-exchange resins
- Author
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Weimin Yang, Yanan Li, Fengping Yu, and He Wenjun
- Subjects
chemistry.chemical_classification ,Materials science ,Nanocomposite ,Polymer nanocomposite ,Graphene ,General Chemical Engineering ,Swelling capacity ,General Chemistry ,Polymer ,law.invention ,chemistry ,Chemical engineering ,law ,Polymer chemistry ,Suspension polymerization ,Thermal stability ,Thermal analysis - Abstract
Graphene-based polymer nanocomposites (GPNCs) were prepared by in situ suspension polymerization and the prepared polymers were chloromethylated with chloromethyl ethyl ether and then aminated with trimethylamine to obtain graphene-based nanocomposite ion-exchange resins (GPNC-IERs). Raman spectroscopy revealed the existence of a chemically bonded interaction between graphene and the polymer networks via the increased intensity and shift in the vibration bands of graphene in the nanocomposites. The reinforced thermal and structural properties of the nanocomposites were investigated with graphene contents from 0 to 1.0 wt%. The thermal stability was evaluated by thermogravimetric-differential thermal analysis (TG-DTA). It showed that the addition of graphene to the polymer matrix greatly increased the onset degradation temperature by 20 °C. The structural properties of the nanocomposites such as swelling capacity and total exchange capacity were improved with 0.4 wt% graphene, which confirmed that the good dispersion of graphene throughout the polymer matrix with strong interaction within the polymer networks played an important role in the properties enhancement effect. With the excellent anti-swelling property and thermal stability, the GPNC-IER catalysts presented a better performance in hydration of ethylene oxide (EO) to monoethylene glycol (MEG) including reaction activity, selectivity and stability in 500 h tests.
- Published
- 2015
27. Synthesis of monodispersed YbF3:Er3+ nanoplates with rhombus shapes
- Author
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Xiaoqin Hou, Shengtai He, Jun Zhou, Qin Li, and Yanan Li
- Subjects
Materials science ,Morphology (linguistics) ,Transmission electron microscopy ,General Chemical Engineering ,Thermal decomposition ,Rhombus ,Nanotechnology ,General Chemistry ,Emission spectrum ,Luminescence - Abstract
Novel monodisperse YbF3:Er3+ nanoplates with regular rhombus shape are synthesized via a thermolysis process. The morphology and luminescence properties have been investigated using transmission electron microscopy and emission spectroscopy.
- Published
- 2015
28. Template-assisted synthesis of ordered single crystal InN nanowires
- Author
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Tingting Xu, Zhuo Chen, Jie Jiang, Chuanbao Cao, Hesun Zhu, Xingyan Xu, Qing Chen, and Yanan Li
- Subjects
Electron mobility ,Photoluminescence ,Materials science ,General Chemical Engineering ,Nanowire ,Nanotechnology ,General Chemistry ,Nitride ,Single crystal - Abstract
Aligned InN nanowires were synthesized by a template-assisted two-step method. The as-synthesized aligned InN nanowires were of single crystal structure and exhibited good electrical properties with a carrier mobility of 93.8 cm2 V−1 s−1 and a strong photoluminescence emission peak at 740 nm at room-temperature. The alignment characteristic makes it more convenient to integrate the nanowires into nanodevices. The two-step method provides an effective and low-cost road for ordered nitride nanowires in a controllable way.
- Published
- 2012
29. The preparation and catalytic performance of graphene-reinforced ion-exchange resins.
- Author
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Yanan Li, Fengping Yu, Wenjun He, and Weimin Yang
- Published
- 2015
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