Dong Xu

Bio: Dong Xu is an academic researcher from Jiangsu University. The author has contributed to research in topics: Microstructure & Varistor. The author has an hindex of 3, co-authored 6 publications receiving 57 citations.

Microstructure and Electrical Properties of La2O3-Doped ZnO-Bi2O3 Based Varistor Ceramics

Abstract: La2O3-doped ZnO-Bi2O3-based varistor ceramics were obtained by a solid reaction route, and the microstructure and electrical properties of the varistor ceramics were studied in this paper. The results showed with addition of 0-1.00mol% La2O3, La2O3-doped ZnO-based varistor ceramics were prepared in this paper with the voltage gradient of 77-503V/mm, the nonlinear coefficient of 2.4-36.8, and the leakage current of 0.09-494μA. The results also showed with addition of 0.08mol% La2O3, La2O3-doped ZnO-based varistor ceramics exhibit comparatively ideal comprehensive electrical properties. Such as the threshold voltage was 320V/mm, the nonlinear coefficient was 36.8 and the leakage current was 0.29μA. The doping of La2O3 affects the form and decomposition of the pyrochlore.

Dielectric Properties of Zn-Doped CCTO Ceramics by Sol-Gel Method

Abstract: The CaCu3-xZnxTi4O12 (CCZTO) (x=0, 0.06, 0.1, 0.2) ceramics were prepared by Sol–gel method. The XRD pattern shows that crystal structure of the sample with no Zn is basically single-phase. The SEM results indicate that the samples have porous structures and the gain size decreases with the content of Zn increasing. The dielectric properties of CCZTO were analyzed by Agilent 4294A. The experimental results show that the dielectric constants are less than that in other papers reported obviously because of their mesoporous structures. With the little doping amount(x=0.06, 0.1), a sharp decrease happened in the dielectric constant (er). The higher er was found when x=0.2, but its dielectric loss (D) had greatly increased and frequency stability of dielectric property became worse. The uniformity of gains was put forward to explain the results which showed great impact on the dielectric constant.

Microstructure and Electrical Properties of ZnO–Bi2O3-Based Varistor Ceramics by Different High-Energy Ball Milling Time

Abstract: The microstructure and electrical properties of ZnO-Bi2O3-based varistor ceramics prepared by the high-energy ball milling were studied. The varistor ceramics samples were characterized by XRD and SEM analysis, as well as by dc electrical measurements, such as the nonlinearity coefficients, leakage current and threshold voltage. The best electrical characteristics were found in sample by the high-energy ball milling 1 h and sintered at 1000 °C for 2 h, which exhibited the threshold voltage was 457 V/mm, the nonlinear coefficient was 59.3 and the leakage current was 1.18 μA.

An Improved Engineering Model of Silicon Solar Cell

Abstract: An improved engineering model of silicon solar cell is proposed, which uses only four electrical parameters under standard test conditions provided by manufactures. Simulation and experimental results show that the model error was 6 percent below for various combinations of solar radiation and temperature and its accuracy is sufficient for most practical engineering cases.

Sintering Time Influences on Microstructure and Electrical Properties of Scandium Doped Zinc Oxide Varistor Ceramics

Abstract: Sc2O3-doped zinc oxide varistor ceramics were prepared by a solid reaction route. The microstructure and the electrical properties was analyzed by scanning electron microscope and X-ray diffraction. Sintering time influences on the microstructure and the electrical properties of Sc2O3-doped zinc oxide varistor ceramics are studied. The results show that the electrical properties of Sc2O3-doped zinc oxide varistor ceramics sintered at 1000 and sintered for 1 h was better: the voltage gradient was 653 V/mm; the leakage current was 0.18 μA and the nonlinear coefficient was 57.1.

Multi-functional materials and structures II : selected, peer reviewed papers from the 2nd International Conference on Multi-functional Materials and Structures, October 9-12, 2009, Qingdao, Shandong, P.R. China

Abstract: With the rapid development of science and technology, the functionalization of structural materials, and the structurization of functional materials are attracting increasing attention in the scientific and engineering fields. The development of multi-functional materials and structures (MFMS), at the micro- and nano-scale levels, has grown rapidly due to the requirement of increasing safety margins for all infrastructure, biomedical and engineering elements. Multi-functional material systems are capable of performing multiple 'primary' functions, simultaneously or sequentially in time, and are specially designed to improve system performance via a reduction in the redundancy between sub-system materials and functions. Materials having special structures can exhibit multi-functional properties. For example, shape-memory alloys can act as actuators as well as sensors, and the aim of composite materials is to exploit each aspect's advantages; plus their synergistic effect. The current collection of peer-reviewed papers focuses on multi-functional materials and structures for various engineering applications, and makes a valuable contribution to the literature on the subject.