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Insulator is one of the most widely used electrical equipment in power system, and its insulation state is related to the safe and stable operation of power system. In order to realize the intelligent diagnosis of the insulation state of the field running insulators, an intelligent diagnosis framework based on cloud computing and deep learning algorithm is designed; the browser / server development mode manages the UV images and videos of insulator discharge, and develops a set of image and video management data According to the database system, the database management system of UV imaging samples is constructed, which integrates the function of insulator visible light recognition and insulator discharge severity assessment based on UV image. The developed software is applied to the inspection of transmission lines and substations, and the application result is good.

the method Singular Spectrum Entropy Analysis (SSEA) studies the complexity and irregular extent of Partial Discharge (PD) signals but cannot fully reflect the intrinsic nonlinear characteristic. In this paper, we apply higher-order statistics to substituting for the co-variance matrix and introduce the Ensemble Empirical Mode Decomposition theory (EEMD) to realize multi-scale as well. The signal energies is also used to weight the entropy values. This method is called Multi-resolution Higher Order Singular Spectrum Entropy Analysis (M-HSSEA) of PD signal herein. Three typical insulation defect models of composite insulator are designed and detected by UHF. The method presented not only enhances the robustness of the phase space reconstruction parameters and improves the noise immunity, but it also fully reflects the nonlinear characteristics of the PD signal.

Monolayer graphene was fabricated using thermal chemical vapor deposition (TCVD) as heat spreaders in electronic packaging. Platinum (Pt) thermal evaluation chips were utilized to evaluate the thermal performance of the graphene heat spreaders. Temperature of hot spot driven at a heat flux of up to 430W·cm-2 was decreased by about 13 °C with the attaching of the graphene heat spreader. We demonstrate the potentials of using CMOS compatible TCVD process to make graphene as heat spreader for power dissipation needs.

A fast-heating scheme is utilized for long VACTN-TIM fabrication directly on metal substrate. VACNT arrays with lengths of more than 100 μm were achieved on Al thin film by a conventional thermal CVD at a low temperature of 600 °C. Our methodology allows patterned VACNT array fabrication using a standard lift-off process for various applications, such as thermal interface materials, super capacitor field emission devices and electronic interconnects.

Carbon nanotube (CNT) growth termination mechanism has been studied using Molecular Dynamic (MD) simulation. Due to catalyst diffusion and interaction between the catalyst and the CNT growth substrates, the catalytic activity needed for CNT nucleation is depleted. Diffusion coefficient of the Fe catalyst on different substrates has been evaluated using averaged mean square displacement (MSD) of the Fe atoms in the simulation. At the CNT growth temperature, Fe on Cu substrate shows the highest diffusion coefficient. The calculated low diffusion coefficient of Fe atoms in Al 2 O 3 substrate confirms the use of Al 2 O 3 as the choice material for the diffusion buffer layer. This is consistent with observations in CNT growth experiments using thermal chemical vapor deposition (CVD). The MD simulation provides a clear demonstration of Al 2 O 3 as an effective diffusion buffer material.

With more and more high power high brightness LEDs adopted in general lighting applications, the state-of-the-art packages cannot meet the requirement of thermal management. Over-heating of an LED will cause premature failure because the efficiency, the spectrum, the reliability and the life of solid state lighting devices strongly depend on successful thermal management. Therefore, the requirement for improving the performance and the reliability poses a significant challenge for novel cooling solutions including applications of heat sinks with active cooling methods and high thermal performance materials. Conventional mechanical fans are not preferred in LED devices due to its high energy consumption, short life and high noise. In this study, cooling fixtures with piezoelectric units are designed to be integrated with high power LED modules. The cooling effect of high performance TIM and piezoelectric units are investigated using numerical modeling method.

An application using vertically aligned carbon nanotube (VACNT) as thermal interface material (TIM) in high-brightness LEDs is demonstrated. VACNT arrays have been synthesized on the top and the bottom surfaces of the aluminum heat slugs and integrated into the LED modules using the designed packaging process. The thermal resistance of the LEDs is characterized using the thermal transient test system (MicRed, T3Ster). Compared with silver epoxy, VACNT-TIM shows a comparable thermal performance. It is found that a proper packaging process plays an important role in the final thermal performance of the LEDs with VACNT-TIM.

With the increasing application of high power LEDs in general lighting, more effective cooling solutions should be considered to maintain a better performance and reliability with lower LED junction temperature. In this paper, it is discussed firstly in detail how to effectively take advantage of high thermal performance materials, such as CNTs, to improve the heat conduction in LED packages. Secondly, the air flow velocity field generated by piezoelectric fans is simulated using 3D fluid structure interaction method (FSI) and verified with experimental data. A cooler with a piezoelectric fan inside is designed as a preliminary study on how to apply piezoelectric fans in LED active cooling.

High quality vertically aligned carbon nanotube (VACNT) arrays have been synthesized on bulk Al alloy (Al6063) substrates with an Fe catalyst using low pressure chemical vapor deposition (LPCVD). The pretreatment process of the catalyst was shown to play a critical role, and it was studied comprehensively and optimized to grow high quality VACNT arrays within a wide range thicknesses of catalyst layer (2nm – 11 nm) and acetylene (C 2 H 2 ) flow rates (100sccm – 300sccm). The thermal performance of the resulting VACNT arrays is evaluated. The minimum thermal interfacial resistance of the Al-CNT-Si interfaces achieved so far is only 4 mm2·K/W, and the average value is 14.6 mm2·K/W.