12 results on '"YUN LU"'
Search Results
2. Fabrication of a novel β-CD-based fluorescence probe for the targeted detection of cholesterol
- Author
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Xin-Lei Meng, Yun Lu, and Tao Shi
- Subjects
Materials science ,Quenching (fluorescence) ,Mechanics of Materials ,Mechanical Engineering ,Proton NMR ,Moiety ,General Materials Science ,Chelation ,Carbon-13 NMR ,Fourier transform infrared spectroscopy ,Photochemistry ,Fluorescence ,Amination - Abstract
Cholesterol-targeted fluorescence probe was fabricated through quenching the CD-P assembly in water/ethanol, where CD served as cholesterol-selective chelator and P moiety, 2-amino-4,6-bis-[(4-N,N-dimethylamino)styryl] pyrimidine, as aggregation-induced enhanced emission luminogen, respectively. The designed CD-P was synthesized by the benzsulfonylation of β-CD with TsCl followed by the amination with P. The 1H NMR, 13C NMR, HRMS, FTIR and WXRD characterizations were carried out to confirm the processes, while UV–Vis and fluorescence spectral results proved the formation of CD-P assemblies at a concentration above 1.0 × 10−4 M, and TEM and AFM images recorded morphological changes of the assemblies upon exposure to quencher and cholesterol. These results helped to illuminate the mechanism beneath the finding that after fluorescence disappearing due to the presence of quencher, the CD-P/Q probe re-brightened owing to the addition of cholesterol and its fluorescence intensity enhanced linearly with the increase in cholesterol.
- Published
- 2020
3. Photoluminescence properties of N-doped carbon dots prepared in different solvents and applications in pH sensing
- Author
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Yun Lu, Mei Yang, Baoyan Li, and Kailiang Zhong
- Subjects
Materials science ,Photoluminescence ,Mechanical Engineering ,Inorganic chemistry ,chemistry.chemical_element ,Protonation ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Fluorescence ,0104 chemical sciences ,chemistry ,Mechanics of Materials ,General Materials Science ,Fourier transform infrared spectroscopy ,0210 nano-technology ,High-resolution transmission electron microscopy ,Carbon ,Surface states ,Visible spectrum - Abstract
Two kinds of nitrogen-doped carbon dots (N-CDs) were synthesized by choosing citric acid, l-serine and monoethanolamine as the precursors, respectively, in organic solvent N,N-dimethylformamide (DMF) and deionized water. The FTIR, UV–Vis, HRTEM and XRD were used to characterize the surface molecular structures of these two N-CDs. It was found that different reaction systems made the as-prepared N-CDs possess varied surface states and thus exhibit distinctive photoluminescence features. For the N-CDs prepared in DMF, its fluorescent property showed pH dependent and color-switchable in visible light and could be reversibly changing over in both alkaline and acidic environments due to the protonation and de-protonation of the carboxyl groups on the surface of the N-CDs. Also, its fluorescence intensity exhibited a linear fashion over the pH range from 1.5 to 7.5, indicating its potential applications in pH quantitative detection under acidic condition.
- Published
- 2017
4. The thiophene derivative with ferricyanide end group and its polymers: synthesis and electrochromic performance
- Author
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Han Yan, Jing Wang, and Yun Lu
- Subjects
chemistry.chemical_classification ,Aqueous solution ,Materials science ,Mechanical Engineering ,Polymer ,Photochemistry ,chemistry.chemical_compound ,End-group ,chemistry ,Polymerization ,Mechanics of Materials ,Electrochromism ,Polymer chemistry ,Thiophene ,General Materials Science ,Ferricyanide ,Derivative (chemistry) - Abstract
A novel thiophene derivative (Fe–Th) with ferricyanide end group is successfully synthesized. The polythiophene derivative (Fe–PTh) is additionally obtained in aqueous solution by polymerization of Fe–Th, and shows a nanoparticle structure with a diameter from 10 to 100 nm. A simple solid-state electrochromic device is fabricated using the Fe–PTh as electrochromic material, and displays a novel three-color electrochromism from blue, green, and red with the increased potential.
- Published
- 2015
5. Improved UV resistance in wood through the hydrothermal growth of highly ordered ZnO nanorod arrays
- Author
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Dongjiang Yang, Yun Wang, Jiasheng Xu, Yixing Liu, Yun Lu, Jian Li, Qingfeng Sun, Haimin Zhang, and Jinchun Tu
- Subjects
Materials science ,Infrared ,Scanning electron microscope ,Mechanical Engineering ,Composite number ,technology, industry, and agriculture ,Nanotechnology ,complex mixtures ,Accelerated aging ,Hydrothermal circulation ,Nanomaterials ,Chemical bond ,Chemical engineering ,Mechanics of Materials ,General Materials Science ,Nanorod - Abstract
In this study, wood materials with significantly improved UV resistance were successfully fabricated by growing highly ordered ZnO nanorod arrays on wood surfaces using a facile one-pot hydrothermal method. The resultant samples were characterized via scanning electron microscopy (SEM), X-ray diffraction, and attenuated total reflectance-Fourier transformation infrared (ATR–FTIR) techniques. The SEM images clearly show the highly ordered and well-aligned ZnO nanorod arrays directly grown onto the wood surface. ATR–FTIR spectra demonstrate that stable chemical bonds between the hydroxyl groups of the ZnO nanorod array film and the wood surface were formed at the interface of the two materials. An accelerated aging test was used to measure the UV resistance of the original wood and the ZnO/wood composite. The experimental results indicate that the ZnO/wood samples exhibited a more superior UV resistance than the original wood. This significantly improved UV resistance is mainly attributed to the excellent UV absorption of the well-aligned ZnO nanorod arrays grown on the wood surface.
- Published
- 2012
6. Growth of hydrophobic TiO2 on wood surface using a hydrothermal method
- Author
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Yun Lu, Qingfeng Sun, and Yixing Liu
- Subjects
Diffraction ,Anatase ,Materials science ,Hydrogen ,Mechanical Engineering ,Analytical chemistry ,chemistry.chemical_element ,Hydrothermal circulation ,Contact angle ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Mechanics of Materials ,Titanium dioxide ,General Materials Science ,Fourier transform infrared spectroscopy ,Spectroscopy - Abstract
Hydrophobic titanium dioxide (TiO2) was successfully grown on a wood surface using a hydrothermal method. Energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and water contact angle (WCA) were employed to characterize the features of grown TiO2 and its hydrophobicity. EDS, XRD, and FTIR proved that anatase TiO2 chemically bonded to the wood surface through the combination of hydrogen groups during the hydrothermal process. The values of WCAs manifested that the hydrophobicity of the treated wood was mainly dependent on specific reaction conditions, especially on reaction pH value and hydrothermal temperature. The highest WCA reached 154° when the hydrothermal temperature was 130 °C. The treated wood thus possessed a superhydrophobic surface.
- Published
- 2011
7. Behavior of electrical resistance of SiCCVD fiber and development of micro-heater with SiCCVD fiber
- Author
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Yun Lu, Mitsuji Hirohashi, and Liang Hao
- Subjects
Materials science ,Heating element ,Mechanical Engineering ,chemistry.chemical_element ,Core (optical fiber) ,chemistry ,Electrical resistance and conductance ,Mechanics of Materials ,Electrical resistivity and conductivity ,General Materials Science ,Fiber ,Composite material ,Temperature coefficient ,Carbon ,Layer (electronics) - Abstract
Behavior of electrical resistance was examined in room temperature and elevated temperatures up to 1000 °C for two types of SiCCVD fibers with diameters of 140 and 70 μm, respectively. The results showed that electrical resistance showed a good linear relationship with the length of fibers. Electrical resistance decreased as temperature increased, besides, temperature coefficient of electrical resistance was a minus constant, −5.2 × 10−4 °C−1 except that in the first heating. In the first heating, electrical resistance and temperature coefficient increased and had a peak in the range of 550–700 °C owing to the burning of the carbon-rich layer on the fiber surface. It suggested that behavior of electrical resistance of the fibers depended mainly on the carbon core and the carbon-rich layer. It was confirmed that SiCCVD fiber could be used as heating elements for micro-heater and finally a micro-heater using SiCCVD fiber as heating elements was developed.
- Published
- 2010
8. Prolonging the combustion duration of wood by TiO2 coating synthesized using cosolvent-controlled hydrothermal method
- Author
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Qingfeng Sun, Yixing Liu, Yun Lu, Jian Li, Yongzhi Cui, and Haipeng Yu
- Subjects
Anatase ,Materials science ,Scanning electron microscope ,Mechanical Engineering ,technology, industry, and agriculture ,Analytical chemistry ,Combustion ,Hydrothermal circulation ,Chemical engineering ,Mechanics of Materials ,Phase (matter) ,Cone calorimeter ,General Materials Science ,Fourier transform infrared spectroscopy ,Layer (electronics) - Abstract
Thin TiO2 coating was grown on wood surface using a cosolvent-controlled hydrothermal method. The surface morphology, chemical composition, and functional groups were examined by the scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDXA), and Fourier transform infrared spectroscopy (FTIR), respectively. The crystalline phase of TiO2 was investigated by the X-ray diffraction (XRD). The combustion test was carried out on the Dual Analysis Cone Calorimeter, according to the fire testing standard ISO 5660-1. Resulted from the combined analysis of SEM and EDXA, FTIR and XRD, it was demonstrated that the anatase TiO2 layer accompanying some spheral morphology chemically bonded to wood surface with intact and smooth appearance. The significant differences in combustion parameters between the untreated and the TiO2 coated wood were observed. In comparison to the untreated wood, the burning time of TiO2 coated wood was doubled, and the smoke, CO, CO2 emissions were markedly reduced. As a result, the TiO2 coating can effectively act as a protective layer to prolong the combustion duration of wood and prevent the harmful gas from spreading.
- Published
- 2010
9. Development of electric heating actuators of fiber reinforced metal composite
- Author
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Mitsuji Hirohashi, Fusheng Pan, and Yun Lu
- Subjects
Materials science ,Mechanical Engineering ,Metal matrix composite ,Hot pressing ,Curvature ,Computer Science::Other ,Computer Science::Robotics ,Electrical resistance and conductance ,Computer Science::Systems and Control ,Mechanics of Materials ,Electric heating ,General Materials Science ,Electric power ,Composite material ,Actuator ,Displacement (fluid) - Abstract
Two types of electric heating actuators used of SiCCVD fiber reinforced aluminum composite were successfully developed, which could be used at elevated temperature. The experimental results reveal that the temperature of the actuators increases with the increase of the given electric power. The maximum temperature was found to be higher the 150 and 200°C for 1-side electric heating actuator and 2-side electric heating actuator, respectively, when the electric power of about 10 W were given. It is found that the electric resistance of the actuators decreases obviously with the increase of temperature. A critical temperature was found to exist for the change of the displacement and curvature. The displacement and curvature almost remained unchanged when the temperature of the actuators was lower than the critical temperature. After that, the displacement and curvature increase with the rise of the actuator temperature. Because the 1-side and 2-side actuators have different response characteristics of the displacement and generated force, it is expected that the two types of actuators may be used in different areas.
- Published
- 2004
10. Behavior of electrical resistance of SiC fiber and development of micro-heater with SiC fiber.
- Author
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Yun Lu, Liang Hao, and Hirohashi, Mitsuji
- Subjects
- *
ELECTRICAL resistivity , *TEMPERATURE , *CARBON composites , *NANOFIBERS , *HIGH temperatures - Abstract
Behavior of electrical resistance was examined in room temperature and elevated temperatures up to 1000 °C for two types of SiC fibers with diameters of 140 and 70 μm, respectively. The results showed that electrical resistance showed a good linear relationship with the length of fibers. Electrical resistance decreased as temperature increased, besides, temperature coefficient of electrical resistance was a minus constant, −5.2 × 10 °C except that in the first heating. In the first heating, electrical resistance and temperature coefficient increased and had a peak in the range of 550-700 °C owing to the burning of the carbon-rich layer on the fiber surface. It suggested that behavior of electrical resistance of the fibers depended mainly on the carbon core and the carbon-rich layer. It was confirmed that SiC fiber could be used as heating elements for micro-heater and finally a micro-heater using SiC fiber as heating elements was developed. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
11. Synthesis of novel coumarin-terminated poly (p-phenylene vinylene)s for application in LEDs.
- Author
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Yan Huang, Zhi-Yun Lu, Qiang Peng, Ru-Gang Xie, Ming-Gui Xie, Jun-Biao Peng, and Yong Cao
- Subjects
- *
COUMARINS , *ANTICOAGULANTS , *PHOTOLUMINESCENCE , *LIGHT emitting diodes , *LIGHT sources , *ELECTROLUMINESCENT devices - Abstract
Novel coumarin-terminated poly (p-phenylene vinylene)s were synthesized successfullyviaGilch methodology. The resulting coumarin end-capped poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene (CT-MEH-PPV) film gives yellow photoluminesence with a maximum intensity at 560 nm, which is noticeably blue-shifted about 40 nm from that of MEH-PPV (598 nm). Light-emitting diode based on a double-layer structure (ITO/PEDOT/CT-MEH-PPV/Ba/Al) showed yellow emission with a maximum brightness of 956 cd m- 2 at 8.8 V and an external quantum efficiency of 0.28% at 49.5 mA cm- 2. The coumarin-terminted poly(2,3-diphenyl-5-hexyl -1,4-phenylene vinylene (CT-DPH-PPV), however, has similar emission spectrum with that of DPH-PPV, but its photoluminescence efficiency (0.78) is much more improved than that of DPH-PPV (0.55). The electroluminescent device (ITO/PEDOT/CT-DPH-PPV/Ba/Al) gave green emission peaked at 510 nm with a maximum brightness of 350 cd m- 2 at 18 V and an external quantum efficiency of 0.04% at 61 mA cm- 2. These results suggest that it is a convenient way to modify the structure of conjugated polymers by terminating to tune the emission color and improve photoluminescent and electroluminescent efficiencies as well. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
12. Development of electric heating actuators of fiber reinforced metal composite.
- Author
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Yun Lu, Hirohashi, M., and Fusheng Pan
- Subjects
- *
ACTUATORS , *COMPOSITE materials , *ALUMINUM , *ELECTRIC power , *TEMPERATURE - Abstract
Two types of electric heating actuators used of SiCCVD fiber reinforced aluminum composite were successfully developed, which could be used at elevated temperature. The experimental results reveal that the temperature of the actuators increases with the increase of the given electric power. The maximum temperature was found to be higher the 150 and 200°C for 1-side electric heating actuator and 2-side electric heating actuator, respectively, when the electric power of about 10 W were given. It is found that the electric resistance of the actuators decreases obviously with the increase of temperature. A critical temperature was found to exist for the change of the displacement and curvature. The displacement and curvature almost remained unchanged when the temperature of the actuators was lower than the critical temperature. After that, the displacement and curvature increase with the rise of the actuator temperature. Because the 1-side and 2-side actuators have different response characteristics of the displacement and generated force, it is expected that the two types of actuators may be used in different areas. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
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