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46 results on '"Shang, Liwei"'

6. Influence analysis of track irregularity on running comfort of Maglev train

Author

Shang Liwei, Xu Weinan, Zhou Xiong, Wang Dongzhou, Huang Jingyu, and Wu Zhewei

Subjects
Vibration, Dynamic simulation, Computer science, Maglev, Control system, PID controller, Train, Track (rail transport), Automotive engineering, Suspension (motorcycle)
Abstract

Background: In this article, the TR08 car of the Shanghai Magnetic Train Demonstration Line was prototyped and a multi-body dynamics simulation model was established. And based on the low-interference track irregularity power spectrum in Germany, track irregularity data was obtained. Used dynamic simulation software, completed the dynamic simulation analysis of the vehicle-rail model controlled by the proportion-integral-derivative control system PID parameters. It can be concluded that the vibration of trains passing through irregular tracks at different speeds, and evaluated its comfort. The optimal solution for the control of the PID parameters of the train also has been derived. Aim: Evaluation of operational comfort and suspension gap control effect of Shanghai Maglev Train Demonstration Line by simulation analysis. Materials and methods of the studies: Simulation analysis. Results: The vibration acceleration and suspension gap of Shanghai Maglev Train Demonstration Line has been obtained. Conclusion: By adjusting the parameters of PID control system, the vibration acceleration of train can be reduced and the ride comfort can be improved.

Published
2018

16. Plasmon-resonance-enhanced visible-light photocatalytic activity of Ag quantum dots/TiO2 microspheres for methyl orange degradation.

Author

Yu, Xin, Shang, Liwei, Wang, Dongjun, An, Li, Li, Zhonghua, Liu, Jiawen, and Shen, Jun

Subjects
*SURFACE plasmon resonance, *VISIBLE spectra, *QUANTUM dots, *PHOTOCATALYTIC oxidation, *X-ray diffraction
Abstract

We successfully prepared Ag quantum dots modified TiO 2 microspheres by facile solvothermal and calcination method. The as-prepared Ag quantum dots/TiO 2 microspheres were characterized by scanning electron microscope, transmission electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy and UV-vis diffuse reflectance spectroscopy. The Ag quantum dots/TiO 2 photocatalyst showed excellent visible light absorption and efficient photocatalytic activity for methyl orange degradation. And the sample with the molar ratio of 0.05 (Ag to Ti) showed the best visible light photocatalytic activity for methyl orange degradation, mainly because of the surface plasmon resonance (SPR) effects of Ag quantum dots to generate electron and hole pairs for enhanced visible light photocatalysis. Finally, possible visible light photocatalytic mechanism of Ag quantum dots/TiO 2 microspheres for methyl orange degradation was proposed in detail. [ABSTRACT FROM AUTHOR]

Published
2018
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31. Analytical model for the dispersion of sub-threshold current in organic thin-film transistors

Author

Liu Ming, Han Maixing, Shang Liwei, Chen Yingping, Ji Zhuoyu, Liu Xin, and Wang Hong

Subjects
Transistor model, Materials science, business.industry, Contact resistance, Transistor, Electrical engineering, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, law.invention, Gate oxide, Thin-film transistor, law, Materials Chemistry, Optoelectronics, Equivalent circuit, Electrical and Electronic Engineering, business, AND gate, Leakage (electronics)
Abstract

This paper proposes an equivalent circuit model to analyze the reason for the dispersion of sub-threshold current (also known as zero-current point dispersion) in organic thin-film transistors. Based on the level 61 amorphous silicon thin-film transistor model in star-HSPICE, the results from our equivalent circuit model simulation reveal that zero-current point dispersion can be attributed to two factors: large contact resistance and small gate resistance. Furthermore, it is found that decreasing the contact resistance and increasing the gate resistance can efficiently reduce the dispersion. If the contact resistance can be controlled to 0 Ω, all the zero-current points can gather together at the base point. A large gate resistance is good for constraining the dispersion of the zero-current points and gate leakage. The variances of the zero-current points are 0.0057 and nearly 0 when the gate resistances are 17 MΩ and 276 MΩ, respectively.

Published
2011

40. Active layer self-protection process for organic field-effect transistors

Author

Shang Liwei, Liu Xinghua, Liu Ming, Wang Hong, Tu Deyu, Liu Jiang, and Liu Ge

Subjects
Organic field-effect transistor, Materials science, business.industry, Bilayer, Transistor, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Active layer, law.invention, Pentacene, chemistry.chemical_compound, chemistry, law, Impurity, Materials Chemistry, Electronic engineering, Optoelectronics, Field-effect transistor, Electrical and Electronic Engineering, business, Layer (electronics)
Abstract

To isolate the active layer from air, double organic layer organic field-effect transistors have been fabricated, based on a two-step vacuum-deposition process. Pentacene acted as the active layer, and subsequently, CuPc was deposited above the pentacene and served as a protecting layer for the active layer. Due to the same electrical characteristics but different morphologies, the bilayer structure was effective in decreasing the contamination of impurities and gas, and then improved the device stability in air.

Published
2009

43. Sub-micrometer Organic Field Effect Transistors

Author

Shang, Liwei, Liu, Ming, Ji, Zhouyu, Liu, Ge, Liu, Xinghua, Liu, Jiang, and Wang, Hong

Abstract

Pentacene organic field effect transistors with a series of sub-micrometer channel have been fabricated and characterized. Source and drain metal electrodes was made by electron-beam lithography and lift-off process. Image reversal photo resist was used to make integrated mask to pattern the organic semiconductor film to reduce the off-state current. And thiol treatment was applied on gold electrodes to modify their surface energy and improve the charge carrier injection. All the devices can behavior as typical p-type transistor, and have obvious saturation. Using electrode and dielectric surface treatment, device performances have significant improvement. All of the performances, including mobility, threshold voltage and on/off current ratio will change with the channel length decreasing because of the low quality interface between the OSC and dielectrics.

Published
2009

44. Phototransistors and Photoswitches From an Ultraclosely \pi-Stacked Organic Semiconductor.

Author

Ji, Zhuoyu, Shang, Liwei, Lu, Congyan, Wang, Long, Guo, Jingwei, Wang, Hong, Li, Dongmei, and Liu, Ming

Subjects
PHOTOTRANSISTORS, ELECTRIC switchgear, ORGANIC semiconductors, LOGIC circuits, ELECTRODES, PHTHALOCYANINES, ORGANIC field-effect transistors
Abstract

In this letter, high-performance organic phototransistors and photoswitches based on an ultraclosely \pi-stacked organic semiconductor, i.e., titanyl phthalocyanine, are fabricated. The p-type transistor exhibited high performance with a hole mobility of \sim\!\4. 5\ \cm^2\cdot\V^-1\cdot \s^-1 and an on/off ratio higher than \3.1 \times \10^7. Phototransistors exhibited high-photoresponse properties with a responsivity at 10.5 A/W and a photosensitivity up to \2.7 \times \10^5. The high performance of the devices showed their potential application in optoelectronic organic integrated circuits. [ABSTRACT FROM PUBLISHER]

Published
2012
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45. Organic Programmable Resistance Memory Device Based on \Au/Alq3/\gold-nanoparticle/Alq3/\Al Structure.

Author

Liu, Xin, Ji, Zhuoyu, Shang, Liwei, Wang, Hong, Chen, Yingping, Han, Maixing, Lu, Congyan, Liu, Ming, and Chen, Junning

Subjects
COLLOIDAL gold, COMPUTER storage devices, ELECTRIC switchgear, ELECTRODES, ALUMINUM compounds, ELECTRIC potential, NANOPARTICLES, ORGANIC electronics
Abstract

In this letter, an organic memory cell based on tris(8-hydroxyquinolinato)aluminum doped with gold nanoparticles is reported. The device can achieve good resistive switching properties, such as a high on/off current ratio of about \10^4, and good retention (4 h at 0.1 V). The device remains in either state even after the power has been turned off and shows a good stability under stress test. The current–voltage characteristics are comprehensively investigated, and a possible mechanism is proposed and well fitted with the experiment data. The results show that the organic memory devices have promising potentials for future flexible electronic systems. [ABSTRACT FROM AUTHOR]

Published
2011
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46. Heterostructured Ag3PO4/TiO2 film with high efficiency for degradation of methyl orange under visible light.

Author

Wang, Dongjun, Li, Zhonghua, Shang, Liwei, Liu, Jiawen, and Shen, Jun

Subjects
*HETEROSTRUCTURES, *SILVER compounds, *TITANIUM dioxide films, *VISIBLE spectra, *CHEMICAL decomposition, *SOLAR energy, *ENERGY consumption
Abstract

Abstract: A heterostructured Ag3PO4/TiO2 film sample was synthesized using a facile method to improve the efficiency for the solar energy conversion of conventional TiO2 material and accelerate its applications. The preparation strategy of this study provides a simple way to fabricate photocatalytic film samples with relatively low cost. The microstructure and the photocatalytic properties of the as-prepared film samples were investigated in detail. The Ag3PO4/TiO2 film sample shows strong visible light absorption ability, together with high photocatalytic efficiency and activity for degradation of methyl orange. Furthermore, the inter-semiconductor hole-transfer mechanism leads to the enhanced visible-light driven activity for this kind of photocatalyst. [Copyright &y& Elsevier]

Published
2014
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