Lu D.-Y.,Jilin Institute of Chemical Technology
Solid State Ionics | Year: 2015
Abstract Incorporation of Tb ions into the BaTiO3 lattice was studied on ceramic samples with 5% Tb and Ba/Ti ratios of 0.987-1.053, using electron paramagnetic resonance (EPR) in combination with X-ray diffraction (XRD), Raman spectroscopy (RS), scanning electron microscopy (SEM), and dielectric measurements. The EPR results provided direct evidence of the existence of Tb ions at Ti sites as Tb4 +, which was characterized by a broad signal with g = ~ 6.5 and an increased concentration of Ti-site Tb4 + ions and a corresponding increase in the Ba/Ti ratio. The Raman charge effect at 805-833 cm- 1 and an EPR signal at g = 2.004 associated with ionized Ti-vacancy defects provided the evidence for the existence of Tb ions at Ba sites as Tb3 +. Because of the change in the Ba/Ti ratio, Tb ions in BaTiO3 exhibited a self-adjustable amphoteric behavior with the mixed valence states of Ba-site Tb3 + and Ti-site Tb4 + utilized to preserve lattice electroneutrality. The ceramic density, morphology of grains, dielectric properties, and Raman charge effect were sensitive to the Ba/Ti ratio. The sample with a Ba/Ti ratio of 0.987 has evident advantages: a higher density, smooth-surfaced grains, lower dielectric loss, and low-temperature dielectric stability approaching to an X5R specification. Defect chemistry of Tb-doped BaTiO3 is discussed. © 2015 Elsevier B.V. All rights reserved.
Jin F.-L.,Jilin Institute of Chemical Technology |
Yop Rhee K.,Kyung Hee University |
Park S.-J.,Inha University
Journal of Solid State Chemistry | Year: 2011
In this study, covalent functionalization of carbon nanotubes (CNTs) was accomplished by surface-initiated epoxide ring-opening polymerization. FT-IR spectra showed that polyether and epoxide group covalently attached to the sidewalls of CNTs. TGA results indicated that the polyether was successfully grown from the CNT surface, with the final products having a polymer weight percentage of ca. 1474 wt%. The O/C ratio of CNTs increased significantly from 5.1% to 29.8% after surface functionalization of CNTs. SEM and TEM images of functionalized CNTs exhibited that the tubes were enwrapped by polymer chains with thickness of several nanometers, forming coreshell structures with CNTs at the center. © 2011 Elsevier Inc. All rights reserved.
Yu J.,Jilin Institute of Chemical Technology
Proceedings - International Conference on Electrical and Control Engineering, ICECE 2010 | Year: 2010
The series resonant converter is a kind of DC to DC converter. The paper introduces the principle of the half bridge series resonant converter and the application of the half bridge series resonant converter in laser power supply. The series resonant converter has the high converting frequency and its output waveform comes near to the sine wave. Like the constant current resource, the series resonant converter also has the feature of high charging efficiency so that it is used as the charging circuit widely in the laser power supply. © 2010 IEEE.
Wang W.,Jilin University |
Wang X.,Jilin University |
Yang Q.,Jilin University |
Fei X.,Jilin University |
And 2 more authors.
Chemical Communications | Year: 2013
A novel surface modification strategy for an electrospun nanofibrous film was reported, allowing detection and removal of copper ions in the aqueous solution. This reusable dual fluorescent-colorimetric nanofibrous film can be utilized conveniently to achieve real-time naked-eye sensing in aqueous medium just like using a test paper. © 2013 The Royal Society of Chemistry.
Guan C.,Jilin Institute of Chemical Technology
Rengong Jingti Xuebao/Journal of Synthetic Crystals | Year: 2011
The nano Li[Ni 1/3Co 1/3Mn 1/3]O 2 powder was synthesized via co-precipitation method with ethanol. The synthesized materials were characterized by XRD and SEM. The results indicated that the average diameter of the nanoparticles was 60 nm. The Li[Ni 1/3Co 1/3Mn 1/3]O 2 powders had layered hexagonal structure with low cation mixing. Galvanostatic charge-discharge tests between 2.8 V and 4.3 V (vs Li/Li +) confirmed the Li[Ni 1/3Co 1/3Mn 1/3]O 2 electrode had good electrochemical properties, especially the high rate discharge capability such as 10 C, which make it meet the requirement for high power application.