Dongjing Liu

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In this paper, a 3 W high power LED array system with an in-line pin fin heat sink is designed, fabricated, and investigated for thermal transient analysis. Preliminary finite element simulation is conducted by ANSYS, and LED array average junction temperature is about 40.9°C. In the experiment, electrical test method is used to evaluate the heat(More)
In this paper, a novel thermal management method of vapor chamber printed circuit board coupled with sunflower heat sink is presented. The finite element method thermal analysis module of a 110 W multi-chip GaN-based white LED lamp is developed by ANSYS parametric design language and user interface design language, the thermal performance of the LED lamp(More)
To ensure high reliability for advanced automotive electronics, investigation and understanding on the failure mechanisms under harsh conditions are needed. New methods and technologies for improved reliability and increased lifetime should be developed. In this paper, an investigation on the effect of high temperature aging on the thermomechanical(More)
Compared with incandescent lamps and fluorescent lamps, nowadays LEDs (Light Emitting Diodes) are power saving, environment-friendly, and have the advantages of long lifetime and flexible color output. Therefore, LEDs are being widely used in many fields. In this paper, three high-power LEDs packaging modules with different packaging structures were(More)
The current methods of preparation of pesticide residue analysis in traditional Chinese medicine were summarized in this paper. And the new preparation techniques used in recent years were reviewed, which included solid-phase micro-extraction (SPME), QuECHERS, matrix solid-phase dispersion (MSPD). In addition, the determination method of the pesticide(More)
A life-prediction approach of solder joints for electronic packaging under combined loading is presented in this paper. The deformations of solder joints are calculated under vibration and thermal cycling loading based on the finite element method. The calculated results are used as the boundary condition of the multi-axial loading to investigate the strain(More)
From the perspective of the irreversible energy loss of the second law of thermodynamics, that is entropy generation, theoretical analysis on the influence of delamination appeared at the die attach (DA) layer on the chip junction temperature of high power LED-COB package is carried out. First, thermal simulation of chip-on-board LED package with different(More)
The understanding of thermal resistance and junction temperature is important in the area of designing efficient, long-lasting high-power Light Emitting Diodes (LEDs) and diode stacks. This paper developed a systematic evaluating program for investigating the effect of location and thickness on the thermal resistance and junction temperature of LED on an(More)
Thermal performances of light-emitting diode (LED) lamp with three types of thermal interface materials (TIMs) under different convection coefficients and input powers are investigated by using finite-element method. Three types of TIMs are conductive silver, Sn63Pb37 of tin alloy solder, and graphene in this paper. The results demonstrate that the(More)