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Weng L.,Harbin University | Li H.-X.,Key Laboratory of Engineering Dielectrics and Its Application | Yang X.-P.,Sixth Academy | Liu L.-Z.,Harbin University
Polymer Composites | Year: 2015

In this article, a series of new silica/polyimide (SiO2/PI) nanocomposite films with high dielectric constant (>4.0), low dielectric loss (<0.0325), high breakdown strength (288.8 kV mm-1), and high volume resistivity (2.498 × 1014 Ω m) were prepared by the hydrolysis of tetraethyl orthosilicate in water-soluble poly(amic acid) ammonium salt (PAAS). The chemical structure of nanocomposite films compared with the traditional pure PI was confirmed by Fourier transform infrared spectroscopy and X-ray diffraction patterns. The results indicated that both the PAAS and the polyamide acid (PAA) material were effectively converted into the corresponding PI material through the thermal imidization and the amorphous SiO2 was embedded in the nanocomposite films without structural changes. Thermal stability of the nanocomposite films was increased though mechanical property was generally decreased with increasing the mass fraction of SiO2. All the nanocomposite films exhibited an almost single-step thermal decomposition behavior and the average decomposition temperature was about 615°C. It was concluded that the effective dispersion of SiO2 particles in PI matrix vigorously improved the comprehensive performance of the SiO2/PI nanocomposite films and expanded their applications in the electronic and environment-friendly industries. © 2015 Society of Plastics Engineers.

Dong J.,Harbin University of Science and Technology | Yin J.,Harbin University of Science and Technology | Yin J.,Key Laboratory of Engineering Dielectrics and Its Application | Guan S.,Harbin University of Science and Technology | And 2 more authors.
2013 International Conference on Optoelectronics and Microelectronics, ICOM 2013 | Year: 2013

As the device size gets smaller and smaller, electrostatic discharge (ESD) has become an important factor affecting the reliability of semiconductor devices. For a Schottky barrier diode (SBD), the P+ ring junction depth has significant impact on ESD robustness. Based on this, the model of a 1A-series SBD chip is established using SILVACO TCAD software in this paper, the ESD failure mechanism and the impact of junction pushing time on P+ ring junction depth, especially on ESD robustness is also investigated by adding HBM mode pulse to anode. The results indicate that the SBD works well when the ESD test level is below 8 kV but failures at the test level of 8 kV because of the over current-induced heat failure; Besides, when time increases from 80 min to 160 min with the increment of 20 min, the junction depth also increases from 1.245 μm to 1.752 μm, at the same time, the current density becomes smaller and the capability of P+ ring sharing electric field with Schottky barrier also gets strengthened respectively, SBD can get HBM-mode ESD robustness range from 5 kV to 20 kV, which means increasing of the junction depth can significantly enhance the HBM ESD robustness of the diode. © 2013 IEEE.

Wang P.,Harbin University of Science and Technology | Zhao H.,Key Laboratory of Engineering Dielectrics and Its Application | Liu J.,Harbin University of Science and Technology | Zhang W.-C.,Harbin University of Science and Technology | Song F.-C.,Harbin University of Science and Technology
Guangdianzi Jiguang/Journal of Optoelectronics Laser | Year: 2012

Due to the fragility of bare fiber Bragg grating (FBG), an approach of polymer and copper capillary packaging for FBG is proposed in this paper. The FBG is coated with acrylate. After the second coating, the FBG is packaged into a blank copper capillary. The FBG can expand or contract freely without strain. The second coating protects bare FBG from damage. The comparison of the experimental results between coated FBG and bare FBG indicates that the temperature sensitivity of coated FBG is nearly the same as that of bare FBG. The thin coating thickness guarantees that the coating thickness is uniform and the spectrum of coated FBG has a good shape. The influence on measurement precision of temperature from strain is decreased. The empirical results show that the coefficient between wavelength and temperature is 0.99929, and the measurement sensitivity is 13.675 pm/°C. The temperature sensor has a good repeatability.

Zhou W.,Xian University of Science and Technology | Zhou W.,Key Laboratory of Engineering Dielectrics and Its Application | Wang Z.,Xian University of Science and Technology | Dong L.,Xian University of Science and Technology | Sui X.,Xian University of Science and Technology
Hecheng Shuzhi Ji Suliao/China Synthetic Resin and Plastics | Year: 2015

Compared to other thermal conductive inorganic particles, boron nitride (BN) is a kind of important thermal conductive and insulting filler in preparing polymer with high thermal conductivity and insulation due to its unique structure and good thermal and electrical comprehensive properties. The research progresses in thermal conductive polymers filled with micro-and nano-sized BN particles were summarized, and the effects of physical properties, surface modification, structure and dosage of BN on the thermal, insulating and mechanical properties of the polymers were emphasized. The BN nanotubes and nanosheets reinforced polymers possess high thermal conductivity, high electric breakdown strength, high insulating resistance, low dielectric constant and dielectric loss, and good mechanical properties in comparison with micrometer BN. Solving the contradiction between high thermal conductivity and high electric breakdown strength is the future development direction of polymer/BN thermal conductive composite. ©, 2015, Hecheng Shuzhi Ji Suliao/China Synthetic Resin and Plastics. All right reserved.

Han B.,Key Laboratory of Engineering Dielectrics and Its Application | Han B.,Shanghai Qifan Wire Admdcable Co. | Jiao M.,CAS Changchun Institute of Applied Chemistry | Li C.,Key Laboratory of Engineering Dielectrics and Its Application | And 5 more authors.
RSC Advances | Year: 2015

Quantum chemical molecular dynamics (QM/MD) simulations based on a self-consistent charge density functional tight-binding (SCC-DFTB) method on SiO2 filler in polyethylene (PE) showed that: in the absence of SiO2, the PE was quickly charged by high-energy electrons, which resulted in C-C or C-H bonds breaking; on the contrary, in the presence of SiO2 nanoclusters, electron trapping and accumulating were dominated by SiO2 nanoclusters rather than polyethylene, which made polyethylene be preferentially protected and increased the initial time of electrical treeing. In our calculations, we also observed double electric layers around the SiO2 nanocluster, in agreement with recent suggestions from experimental observations. Furthermore, compared with some other investigated nanoclusters, SiO2 was regarded as the most promising candidate attributed to the highest electron affinity. We further observed that once the high-energy electrons were supersaturated in the nanoclusters, the polyethylene chains would be unavoidably charged and C-H bond breaking would occur, which resulted from the interaction between H and O or Si in the nanoclusters. Following that, decomposing and cross-linking of the polyethylene chains were involved in the initial growth of electrical treeing. The current observation can potentially be used in power cable insulation. © The Royal Society of Chemistry 2016.

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