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108 results on '"Zhao Kun-Yu"'

1. Preparation of Transparent TiO2 Nanoporous Coating with Highly Photocatalytic Activity by Anodizing Ti Film with Loose Structure

Author

LIANG Yin, LI Peng, PEI Wang, DUAN Jin-hui, HUANG Feng, and ZHAO Kun-yu

Subjects
Ti film, TiO2 nanopore, transparent, photocatalysis, hydrophilic, Materials of engineering and construction. Mechanics of materials, TA401-492
Abstract

The Ti film with special structure was deposited onto glass substrate by magnetron sputtering, then via the process of electrochemical anodization and annealing, a transparent TiO2 nanoporous coating (denoted as TNP) with high photocatalytic activity can be directly formed on glass substrate. The crystal structure of the TNP was detected by X-ray diffractometry (XRD) and the morphology of the coating was observed by scanning electron microscopy (SEM). The transmittance, wettability and adhesion of TNP were investigated by UV-Vis spectrophotometer, contact angle meter and scratch tester respectively. Finally, the photocatalytic activity of TNP was evaluated by degradation of methylene blue solution under UV illumination. The results show that the prepared TNP coating has a nanoporous structure and only anatase can be found after annealing, the transmittance of TNP coating can reach 80% or more in visible region, with a super hydrophilic surface (contact angleC0=1×10-5mol/L) can reach 94% in 2 hours and the photocatalysis reaction rate constant is 1.47h-1.

Published
2016
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19. Nanoscale Elastic Response of Grain Boundaries in ZnO Varistors by Acoustic Mode AFM

Author

Cheng Li-Hong, Zeng Jiang-Tao, Song Hong-Zhang, Yin Qingrui, Li Guorong, Hui Sen-Xing, Zhao Kun-Yu, Zeng Hua-Rong, and Cai Wen-Jie

Subjects
Inorganic Chemistry, Scanning probe microscopy, Materials science, Atomic force microscopy, Mode (statistics), Varistor, General Materials Science, Grain boundary, Composite material, Nanoscopic scale
Published
2009

20. Acoustic Imaging Frequency Dynamics of Ferroelectric Domains by Atomic Force Microscopy

Author

Shunji Takekawa, Hui Sen-Xing, Kenji Kitamura, Song Hong-Zhang, Zhao Kun-Yu, Yin Qing-Rui, Zeng Hua-Rong, Li Guorong, Kiyoshi Shimamura, Encarnación G. Víllora, and Chinna Venkadasamy Kannan

Subjects
Materials science, business.industry, Acoustics, General Physics and Astronomy, Atomic force acoustic microscopy, Acoustic microscopy, Acoustic wave, Ferroelectricity, Piezoelectricity, Optics, Piezoresponse force microscopy, Electric field, Microscopy, business
Abstract

We report the acoustic imaging frequency dynamics of ferroelectric domains by low-frequency acoustic probe microscopy based on the commercial atomic force microscopy It is found that ferroelectric domain could be firstly visualized at lower frequency down to 0.5 kHz by AFM-based acoustic microscopy The frequency-dependent acoustic signal revealed a strong acoustic response in the frequency range from 7kHz to 10kHz, and reached maximum at 8.1kHz. The acoustic contrast mechanism can be ascribed to the different elastic response of ferroelectric microstructures to local elastic stress fields, which is induced by the acoustic wave transmitting in the sample when the piezoelectric transducer is vibrating and exciting acoustic wave under ac electric fields due to normal piezoelectric effects.

Published
2008

44. Nanoscale Thermal Response in ZnO Varistors by Atomic Force Microscopy

Author

Zhao Kun-Yu, Yin Qing-Rui, Cheng Li-Hong, Zeng Hua-Rong, Hui Sen-Xing, Li Guorong, and Song Hong-Zhang

Subjects
Materials science, business.industry, Spinel, General Physics and Astronomy, Varistor, Nanotechnology, Conductive atomic force microscopy, Scanning thermal microscopy, engineering.material, Signal, Condensed Matter::Materials Science, Thermal conductivity, Thermal, engineering, Optoelectronics, business, Nanoscopic scale
Abstract

We report the application of customer-built scanning thermal microscopy (SThM) based on a commercial atomic force microscope to investigate local thermal inhomogeneity of ZnO varistors. The so-called 3ω method, generally used for measuring macroscale thermal conductivity, is set up and integrated with an atomic force microscope to probe the nanoscale thermal property. Remarkably, thermal contrasts of ZnO varistors are firstly imaged by the SThM, indicating the uniform distribution of spinel phases at triple points. The frequency-dependent thermal signal of ZnO varistors is also studied to present quantitative evaluation of local thermal conductivity of the sample.

Published
2009

46. The Observation of Martensite and Magnetic Domain Structures in Ni53Mn24Ga23 Shape Memory Alloys by Scanning Electron Acoustic Microscopy and Scanning Thermal Microscopy.

Author

Zhao Kun-Yu, Zeng Hua-Rong, Song Hong-Zhang, Hui Sen-Xing, Li Guo-Rong, and Yin Qing-Rui

Subjects
*MARTENSITE, *FERROMAGNETIC materials, *MAGNETIC domain, *SHAPE memory alloys, *SCANNING electron microscopy, *ACOUSTIC microscopy, *SCANNING probe microscopy, *CRYSTALLOGRAPHY, *MAGNETIC force microscopy
Abstract

We present observations of martensite variants and ferromagnetic domain structures of Ni53Mn24Ga23 ferromagnetic shape memory alloys with a pure tetragonal martensitic phase by using scanning electron acoustic microscopy (SEAM) and scanning thermal microscopy (SThM). Electron acoustic images show a polycrystalline morphology with martensite variants. Direct coincidence between crystallographic martensitic twin variants and magnetic domains is found. A domain-like structure, obtained by SThM, is firstly reported, and then confirmed by magnetic force microscopy (MFM). The experimental results will be helpful for investigating the local thermal properties of ferromagnets and understanding the relationship between martensite variants and magnetic domains. [ABSTRACT FROM AUTHOR]

Published
2012
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47. Synthesis of Ni0.6Cu0.4Fe2O4 Ferrite Fine Powder Using Egg White Method

Author

Wang, Lei, Li, Zhi Dong, Liang, Yin, and Zhao, Kun Yu

Abstract

Polycrystalline ferrites powders samples: Ni0.6Cu0.4Fe2O4 were synthesized by using metal nitrates and freshly extracted egg white, all the samples were sintered at 500°C,520°C, 550°C, 580°C and 600°C for 3h,6h,9h, respectively. The better synthesis conditions were investigated by analyzed the effect of sintering temperature and soaking time on structural, grain size and magnetic properties using X-ray diffraction (XRD), laser grain size analyzer (LPSA) and vibrating sample magnetometer (VSM). From the above analysis, the better synthesis conditions is set two insulation work steps: First at 240°C for 1h, then heating to 440°C for 2h, finally sintering at between 520°C and 550°C for 6h.

Published
2014
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48. Synthesis and Properties of Ca3Co4-xCuxO9 (0≤x≤1.4)

Author

Liang, Yin, Wang, Lei, Zhao, Kun Yu, Li, Zhi Dong, and Tang, Xue Lian

Abstract

Ca3Co4xCuxO9 (0x1.4) misfit-layered thermoelectric oxides were prepared by traditional solid-state reaction method which cost less, operate easer, may produce Ca3Co4O9 on large scale. XRD study shows that we obtain Ca3Co4O9 major phase in series Ca3Co4xCuxO9 (0x1.4) samples which were sintered at the highest temperature 880°C for 8h by two steps. Metallographic microscopic analysis indicates that some samples grain size range at 2~4μm which were doped less Cu. Doping Cu in different way experiment suggests that Ca3Co4xCuxO9 (x=0.4) sample has lower electric resistivity while Ca3Co4O9+5%Cu samples resistivity increases, compared with Ca3Co4O9 (x=0). The article infers that Ca3Co4xCuxO9 (0x0.4) can decrease the electric resistivity of Ca3Co4O9.

Published
2013
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49. Effect of Cl- Content, pH Value and CO2 on Electrochemical Corrosion Features of Cr15 Super Martensitic Stainless Steel

Author

Long, Jin Ming, Liu, Quan Bin, Zhao, Kun Yu, Yong, Qi Long, and Su, Jie

Abstract

The corrosion behavior of a Cr15 super martensitic stainless steel (Cr15 SMSS) was investigated in NaCl solutions by means of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Effects of Cl- content, pH value and saturated CO2 on corrosion were sdudied. It was found that the parameters of maintaining passivity current density (ip), the critical pitting potential (Eb) and charge transfer resistance (Rt) of Cr15 SMSS varied widely under different conditions. The corrosion resistance of Cr15 SMSS decrease with increasing Cl- concentration and lowering pH value. Both ip and Eb increase for Cr15 SMSS in CO2-saturated NaCl solution, which verified that the CO2 in NaCl solution can result in lower pitting sensitivity and higher uniform corrosion rate to Cr15 SMSS.

Published
2013
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50. Effect of Chloric Ions and Temperature on the Pitting Corrosion Behavior of Supermartensitic Stainless Steel in CO2-Saturated Chloride Solution

Author

Li, Jun, Ye, Dong, Chen, Yong Mei, Su, Jie, and Zhao, Kun Yu

Abstract

Abstract. The pitting corrosion behavior of two kinds (W and Cu-free; W and Cu-bearing) of supermartensitic stainless steels (SMSS) were studied in CO2-saturated chloride solution with three chloric ion concentration: 21200, 50000, 100000ppm, and four different temperatures:19, 40, 60, 80°C by potentiodynamic polarization measurement. The results indicate that the pitting potential decreased with temperature increasing, and in a logarithmic relation with the chlorine concentration in both alloys. The pitting potential of supermartensitic stainless steel is increased by together adding tungsten and copper.

Published
2012
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