Yu Zhou

Name:

Organization: Harbin Institute of Technology

Department: Department of Chemistry, School of Materials Science and Engineering

Title:

Chemicals
References

Two dielectric anomalies and impedances of the x CoFe2O4 - (1-x) Bi3.15Nd0.85Ti3O12 (x = 0, 0.3, 0.5) ceramics with coherent interfaces

Co-reporter:Hongjun Zhang, Hua Ke, Gang Zeng, Dechang Jia, Yu Zhou

Scripta Materialia 2017 Volume 135(Volume 135) pp:

Publication Date(Web):1 July 2017

DOI:10.1016/j.scriptamat.2017.03.021

Two temperature dependence dielectric anomalies are observed in the series of CoFe2O4 (CFO)/Bi3.15Nd0.85Ti3O12 (BNdT) composite ceramics arising from a periodic structural fluctuation found by high resolution transmission electron microscopy (HRTEM) in the BNdT phase. The latter dielectric anomaly upshifts from 580 °C to 760 °C with the increasing of CFO contents. Higher Curie temperatures are attributed to the larger orthorhombicity values with the effects of the different thermal expansion coefficients and the coherent interfaces between BNdT and CFO. The conductive mechanisms stemming from grain boundaries and plate boundaries were merged into one process approximately for proper CFO contents.Download high-res image (218KB)Download full-size image

Effects of mesoporous structure and UV irradiation on in vitro bioactivity of titania coatings

Co-reporter:Ya-Ping Guo, Hai-Xiong Tang, Yu Zhou, De-Chang Jia, Cong-Qin Ning, Ya-Jun Guo

Applied Surface Science 2010 Volume 256(Issue 16) pp:4945-4952

Publication Date(Web):1 June 2010

DOI:10.1016/j.apsusc.2010.03.007

Abstract

Mesoporous titania coatings (MTCs) with a pore size of 4.75 nm were prepared on Ti6Al4V substrates by a sol–gel process, and then irradiated with UV light at room temperature for 2 h. The effects of mesoporous structure and UV irradiation on the in vitro bioactivity were investigated. Simulated body fluid (SBF) tests reveal that the MTCs exhibit a high apatite-forming ability, which may be attributed to the following reasons: (i) the BET surface area of the MTCs is ∼190 m²/g, resulting in a greater density of Ti–OH groups than that without mesoporous structure; (ii) theoretical analysis reveals that the mesoporous structure can improve the driving force and nucleation rate of apatite precipitation in SBF. As compared with the MTCs, the UV-irradiated coatings do not exhibit any change in phase components and surface morphologies. However, the apatite-forming ability is higher on the UV irradiation coatings than on the MTCs because of the increase of Ti–OH groups and the improvement of wettability after UV irradiation. In addition, the investigation of the MG63 cell proliferation on the both substrates was performed. The results indicate that the MTCs before and after UV irradiation exhibit a good biocompatibility and are fit for the MG63 cell proliferation.

Field-Assisted Synthesis and Electromagnetic Properties of Aligned Magnetic Nanostructures by γ-Irradiation Induced Reduction

Co-reporter:Hongtao Zhao ; Bin Zhang ; Jusheng Zhang ; Lifang Zhang ; Xijiang Han ; Ping Xu

The Journal of Physical Chemistry C 2010 Volume 114(Issue 49) pp:21214-21218

Publication Date(Web):November 17, 2010

DOI:10.1021/jp107903r

We here demonstrate the preparation of magnetic nanostructures (Co, Ni) with aligned morphologies through a magnetic field-assisted γ-irradiation route. It is found out that a proper magnetic field can induce the prepared magnetic nanoparticles to align into well-defined stick or chain structures, where randomly dispersed nanoparticles are obtained without the application of magnetic field. The alignment of the magnetic nanoparticles gives rise to increased magnetization and coercivity due to the enhancement in shape anisotropy. Meanwhile, compared with the scattered nanoparticles, stronger electromagnetic wave absorption properties can also be realized in the aligned nanostructures, caused by the geometrical effect. We think this alignment of magnetic nanoparticles into specific structures under the assistance of magnetic field may be appealing in improving the electromagnetic wave absorptions that are not accessible in randomly dispersed particles.