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1. chinaXiv:201705.00268 [pdf]

Ultra low water adhesive metal surface for enhanced corrosion protection

Wang, G [Wang, Gang][ 1 ]; Zeng, ZX [Zeng, Zhixiang][ 2 ]; Chen, JJ [Chen, Junjun][ 2 ]; Xu, MY [Xu, Mengya][ 2 ]; Zhu, JF [Zhu, Jingfang][ 2 ]; Liu, S [Liu, Shuan][ 2 ]; Ren, TH [Ren, Tianhui][ 1 ]; Xue, QJ [Xue, Qunji][ 2 ]
Subjects: Materials Science >> Materials Science (General)

A superhydrophobic surface with ultra low water adhesive force is fabricated on various metals for enhanced corrosion protection. The superhydrophobic surface is constructed by passivated zinc oxide (ZnO) and low surface energy poly(dimethylsiloxane) (PDMS). The process of wettability transformation and corrosion are evaluated by a salt spray test and electrochemical measurement. The superhydrophobic surface is separated layer-by-layer to reveal the function of each layer in corrosion protection. The surface adhesive force is applied as a novel metric for precisely determining the wettability state on the substrate surface. The results reveal that the ultra low water adhesive force of the superhydrophobic surface can effectively suppress water condensation on the metal surface which can suppress the transformation from the Cassie to Wenzel state. The superhydrophobic surface can effectively inhibit corrosion because of the synergistic effect of the triple layered protection system of air, PDMS and ZnO.

submitted time 2017-05-09 Hits15706Downloads766 Comment 0

2. chinaXiv:201705.00598 [pdf]

Simple and Green Fabrication of a Superhydrophobic Surface by One-Step Immersion for Continuous Oil/Water Separation

Zhu, JF [Zhu, Jingfang][ 1,2 ]; Liu, B [Liu, Bin][ 1 ]; Li, LY [Li, Longyang][ 2 ]; Zeng, ZX [Zeng, Zhixiang][ 2 ]; Zhao, WJ [Zhao, Wenjie][ 2 ]; Wang, G [Wang, Gang][ 2 ]; Guan, XY [Guan, Xiaoyan][ 2 ]
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

In this paper, stainless steel meshes with super-hydrophobic and superoleophilic surfaces were fabricated by rapid and simple one-step immersion in a solution containing hydrochloric acid and stearic acid. The apparent contact angles were tested by a video contact angle measurement system (CA). Field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectrosco-py (FTIR), and X-ray photoelectron spectroscopy (XPS) were conducted to characterize the surface topographies and chemical compositions. The SEM results showed that mesh surfaces were covered by ferric stearate (Fe[CH3(CH2)16COO]2) with low surface energy. The CA test results showed that the mesh had a maximum apparent contact angle of 160 ± 1.0° and a sliding angle of less than 5.0°for the water droplet, whereas the apparent contact angle for the oil droplet was zero. Ultrasound oscillation and exposure tests at atmospheric conditions and immersion tests in 3.5 wt % NaCl aqueous solution were conducted to confirm the mesh with excellent superhydrophobic and superoleophilic properties. On the basis of the superhydrophobic mesh, a miniature separation device pump was designed to collect pure oil from the oil/water mixture. It showed that the device was easier and convenient. The techniques and materials presented in this work are promising for application to wastewater and oil spill treatment.

submitted time 2017-05-02 Hits12787Downloads503 Comment 0

3. chinaXiv:201703.00306 [pdf]

Azimuth High Resolution for a Conically Scanned Pencil-Beam Scatterometer Using Rotating Azimuth Doppler Discrimination

Wang, Gang; Dong, Xiaolong; Zhu, Di; Bao, Qingliu
Subjects: Geosciences >> Space Physics

In order to satisfy a relatively high resolution for the retrieval of snow water equivalent, an X/Ku-band dual-frequency full-polarized SCATterometer (DFPSCAT) onboard Water Cycle Observation Mission (WCOM) satellite is designed for high-resolution observations. However, given the following situations, the method called “rotating azimuth Doppler discrimination” is proposed, which can satisfy the resolution requirement and real-time processing: 1) the conically rotation rate of antenna is relatively fast; 2) the swath width is larger than 1000?km; and 3) day or night observation capabilities are required. Considering the complexity of the system's design and the improvement of azimuth resolution capability, a burst pulsing scheme is addressed to satisfy the numbers of azimuth sampling. The simulation model is used to analyze the feasibility of azimuth discrimination method based on geometry and system parameters. It is shown that the achievable azimuth resolution is about 2–5?km at far end of the swath and only 5km at near end of the swath. The results show that when the size of a slice is set as 2–5?km, the Kpcis about less than 0.4 as snow depth varies, and the Kpcof combined slices is smaller than a single slice.

submitted time 2017-03-10 Hits15444Downloads1132 Comment 0

4. chinaXiv:201605.00289 [pdf]

AN UNFOCUSED SAR DESIGN TO IMPROVE AZIMUTH RESOLUTION OF DUALFREQUENCY FULL-POLARIZED SCATTEROMETER

Wang, Gang; Dong, Xiaolong; Bao, Qingliu; Zhu, Di; Xu, Xingou
Subjects: Geosciences >> Space Physics

In order to satisfy a high resolution for the measurement of snow water equivalent, we use the system of using the dual frequency(X-band 9.6GHz and Ku-band 17GHz) and full polarization. This paper discusses the various system options(scanning pencil-beam, high PRF, high SNR) and tradeoffs considered for improving the azimuth resolution of scatterometer are required.

submitted time 2016-05-03 Hits1193Downloads716 Comment 0

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