Search

Your search keyword '"Wang, Caifeng"' showing total 375 results
Start Over Author "Wang, Caifeng"
375 results on '"Wang, Caifeng"'

101. Surface ammonification of the mutual-irradiated aramid fibers in 1,4-dichlorobutane for improving interfacial properties with epoxy resin

Author

Wang Caifeng, Xie Fei, Zhong Zhengxiang, Huang Yudong, Wang Wei, Chuyuan Jia, Yuguang Liu, Zhao Min, Li Liu, and Lixin Xing

Subjects
Materials science, Polymers and Plastics, Scanning electron microscope, 02 engineering and technology, General Chemistry, Epoxy, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Surface energy, 0104 chemical sciences, Surfaces, Coatings and Films, Aramid, visual_art, Ultimate tensile strength, Materials Chemistry, visual_art.visual_art_medium, Surface modification, Composite material, 0210 nano-technology, Curing (chemistry), Tensile testing
Abstract

The mutual irradiated aramid fibers in 1,4-dichlorobutane was ammoniated by ammonia/alcohol solution, in an attempt to improve the interfacial properties between aramid fibers and epoxy matrix. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), dynamic contact angle analysis (DCA), interfacial shear strength (IFSS), and single fiber tensile testing were carried out to investigate the functionalization process of aramid fibers and the interfacial properties of the composites. Experimental results showed that the fiber surface elements content changed obviously as well as the roughness through the radiation and chemical reaction. The surface energy and IFSS of aramid fibers increased distinctly after the ammonification, respectively. The amino groups generated by ammonification enhanced the interfacial adhesion of composites effectively by participating in the epoxy resin curing. Moreover, benefited by the appropriate radiation, the tensile strength of aramid fibers was not affected at all. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44924.

Published
2017

116. Preparation of reversible photoresponsive N-hydroxyethyl spiropyran/polyacrylonitrile fiber materials with mechanical stability by electrospinning for regulating wettability and humidity automatically.

Author

Wang, Caifeng, Liu, Zhenfu, Li, Chunhao, Wu, Yun, and Wang, Shuai

Subjects
*POLYACRYLONITRILES, *WETTING, *HUMIDITY, *VISIBLE spectra, *TENSILE strength, *PHOTOISOMERIZATION, *CARBON fibers, *FIBERS
Abstract

Novel photoresponsive N-hydroxyethyl spiropyran (SP-OH)/polyacrylonitrile (PAN) fiber materials with reversible changes in wettability and humidity were prepared by electrospinning in this work. SP-OH and PAN were mixed through a physical doping method. The wettability and humidity regulation of the electrospun films can be reversibly manipulated by the simple change of ultraviolet (UV)-visible (UV-Vis) light irradiation due to the photoisomerization mechanism of the spiropyran chromophore. Under UV light irradiation, SP-OH molecules exhibit a colored polar open-ring status, resulting in electrostatic attraction with water. However, under visible light irradiation, they are colorless and nonpolar and lose the attraction effect. Wettability and ambient humidity were regulated by this repeated transformation between polar surface and nonpolar surface. The tensile strength and the reversible change ranges of wettability and humidity under UV-Vis irradiation are all closely related to the doping amount of SP-OH. Electrospinning is a promising method to achieve large-scale production that can put such a material into practical application. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

123. Characterization of ZnS films on different substrates by pulsed laser deposition

Author

Wang, Caifeng, Xing, Zhenyue, Feng, Weiwei, Xu, Ling, and Ye, Yingchun

Abstract

ZnS films were deposited on Si and quartz substrates via pulsed laser deposition, and the structure, morphology and photoelectric characteristics of as-deposited and annealed ZnS films were compared. X-ray diffractometer results show that ZnS films are polycrystalline, and the intensity of peak at 28.4° on Si is larger, with a narrower FWHM. atomic force microscope topographies show that the surface of ZnS films becomes rough after annealing, and the roughness on quartz is obviously larger than that on Si. The transmittance of ZnS films in the visible light region reaches 80%, which indicates that ZnS is suitable for making transparent conductive films. PL spectra show that there are two luminescence peaks at 425 and 445 nm related to the intrinsic defect levels of ZnS. Due to the small lattice mismatch, PL intensity on Si is significantly weaker than that on quartz. I–Vcharacteristics of ZnS/p-Si heterojunctions show typical p–n junction diode-like rectification behavior.

Published
2023
Full Text
View/download PDF

124. Stiffness computation of a decoupled micro gyroscope and the effect of machining error

Author

Yao Fenglin, Wang Caifeng, and Gao Shiqiao

Subjects
Microelectromechanical systems, Rate integrating gyroscope, Computer science, Stiffness, Natural frequency, Image processing, Gyroscope, law.invention, Surface micromachining, Machining, law, Electronic engineering, medicine, medicine.symptom
Abstract

This paper introduces a structure of decoupled micro gyroscope. And derives the analytical stiffness calculation of the drive mode and the detect mode. After the manufacture, it uses the microscope and the micro image dimension measurement software to measure the micro gyroscope. By using the measured data and the equivalent elastic modulus, the natural frequency of the drive mode and the detect mode are calculated. By the video and the image processing method, it dynamically tests the drive mode of the micro gyroscope and gets the resonant frequency of the drive mode. The result proofs that the machining error has great effect on the natural frequency of the drive mode of micro gyroscope. And two ways of calculating and testing the natural frequency of the drive mode of the micro gyroscope are effective methods. On the other hand, using the video and the image processing method will provide a novel method for MEMS test.

Published
2011

132. Association Between Organophosphate Pesticide Exposure and Thyroid Hormones in Pregnant Women.

Author

Yiwen Wang, Limei Chen, Caifeng Wang, Yi Hum, Yu Gao, Yijun Zhou, Rong Shi, Yan Zhang, Michihiro Kamijima, Jun Ueyama, Ying Tian, Wang, Yiwen, Chen, Limei, Wang, Caifeng, Hum, Yi, Gao, Yu, Zhou, Yijun, Shi, Rong, Zhang, Yan, and Kamijima, Michihiro

Subjects
LONGITUDINAL method, ORGANOPHOSPHORUS compounds, PESTICIDES, THYROTROPIN, THYROXINE, TRIIODOTHYRONINE, CROSS-sectional method, MATERNAL exposure
Abstract

Copyright of Epidemiology is the property of Lippincott Williams & Wilkins and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2017
Full Text
View/download PDF

137. Electrophoretically deposited “rigid-flexible” hybrid graphene oxide-polyethyleneimine on carbon fibers for synergistically reinforced epoxy nanocomposites

Author

Li, Xiaoyu, Chen, Peng, Sun, Xiaolu, AlMasoud, Najla, Wang, Caifeng, Alomar, Taghrid S., Algadi, Hassan, Sun, Bin, Lian, Zhaolong, and Guo, Xingkui

Abstract

Through electrophoretic deposition (EPD), hybrid graphene oxide-polyethyleneimine–coated carbon fibers (named as ACF/GO-PEI) were prepared to improve the interfacial performances between carbon fibers and epoxy matrix. These rigid GO sheets and flexible PEI polymer could work together, resulting in the improvement of mechanical performances. In this strategy, rigid GO sheets make mechanical interlocking in the interface of composites, and flexible PEI bridges all three parts, i.e., fiber, GO, and epoxy, by covalent bond and electrovalent bond. Moreover, homogenized distribution of the GO-PEI sheets covered on carbon fiber owing to the electrostatic interactions of the positively charged ions and steric effect, effectively increasing the surface roughness and surface energy. The interfacial shear strength (IFSS) of ACF/GO-PEI reinforced epoxy composite could reach 79.2 MPa. In comparison with untreated one, the value was enhanced 69.2%. This study provides new ideas for expanding the application of nanocomponents in traditional composite materials.

Published
2023
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results