Browsing by Author "Liu, X"

Now showing 1 - 4 of 4

item: Article-Full-text
Effect of post-annealing on microstructure and piezoelectric properties of ZnO thin film for triangular shaped vibration energy harvester
(Elsevier, 2019) Zhang, X; Wang, P; Liu, X; Zhang, W; Zhong, Y; Zhao, H; Shi, S; Jin, S; Amarasinghe, YWR
In this paper, a triangular shaped piezoelectric vibration energy harvester (TS-PVEH) with zinc oxide (ZnO) thin films as the piezoelectric layer is reported. The effect of post-annealing temperature on the microstructure and piezoelectric performance of ZnO thin film deposited by magnetron sputtering method is investigated firstly. The results show that the optimum post-annealing temperature of 150 °C was the most beneficial to improve the piezoelectric properties of ZnO thin films. Four prototypes of TS-PVEH with different structure parameters are fabricated and optimized. The simulation and experiment results indicate that the height and width of the triangular structure have a significant influence on the vibration mode and the output performance of TS-PVEHs. The optimization results indicate that the third prototype has the best output performance. Its open-circuit voltage and short-circuit current are 290 mV and 1.25 μA, respectively, when the vibration acceleration is 5 m/s2 and the frequency is 56 Hz. Moreover, it has the highest load power density of 0.035 μW/cm2 when the load is 0.1MΩ.
item: Conference-Full-text
Fired-siltstone based geopolymers for co2 sequestration wells
(IEEE, 2018-05) Ranathunga, A; Gamage, RP; Liu, X; Chathuranga, D
Wellbore integrity during Carbon Dioxide (CO2) storage in deep aquifers is a major problem as the currently used well cement will lose its integrity at higher temperatures and eventually leads to CO2 leakage into the atmosphere. Researchers have conducted several studies in order to find a proper well cement material and have tested several types of geopolymers mixing fly ash and different type of cements with an alkaline solution curing in different temperatures. This paper presents a study on geopolymer composites made from fired siltstone, slag as well as alkaline liquid which were cured at temperatures ranging from 23 0C to 80 0C. Five different types of geopolymer were prepared with ratios of fired siltstone (to 700 oC) and slag as 0:100, 20:80, 30:70, 40:60 and 50:50, separately. After preparing samples with various proportions under different temperatures, the mechanical properties of them were compared. The experimental results reveal that optimum curing temperature range is 50 to 70 0C and addition of higher proportion of slag would help geopolymer gain better performance on mechanical strength compared to other geopolymer materials.
item: Conference-Full-text
A Novel approach for personalized article recommendation in online scientific communities
(2015-06-09) Sun, J; Ma, J; Liu, X; Liu, Z; Wang, G; Jiang, H; Silva, ATP
Rapid proliferation of information technologies has generated sheer volume of information which makes scientific research related information searching more challenging. Personalized recommendation is the widely adopted technique to recommend relevant documents to researchers. Current methods are suffering from mismatch problem and match irrelevance problem and fail to generate highly related results. To overcome these problems, we propose a novel approach to recommend articles to the researchers. In our approach we integrate three types of similarity measures: keyword similarity, journal similarity, and author similarity to measure the relevance of the articles to researchers. The keyword similarity is used to generate candidate list of articles, and the journal similarity and author similarity are used to select most suitable articles from the candidate list. The integrated similarity measure is used to rank the articles based on their relevance. The proposed method is implemented in Scholar Mate (www.scholarmate.com), the online research social network platform. The evaluation results exhibit that proposed method is more effective than existing ones.
item: Article-Full-text
A piezoelectric power generator based on axisymmetrically distributed PVDF array for two-dimension vibration energy harvesting and direction sensing
(Elsevier, 2021) Wei, X; Liu, X; Zheng, C; Zhao, H; Zhong, Y; Amarasinghe, YWR; Wang, P
To achieve vibration energy collection in multiple directions, this paper reports a piezoelectric power generator with an axisymmetrically distributed PVDF array, which is used to acquire 2D vibration energy and monitor the vibration direction. The simulations and the experiments demonstrated that the flexible cylinder with an arcshaped axisymmetrically distributed PVDF array, can harvest vibration energy form multiple directions. Meanwhile, the concept of angular bandwidth is proposed, which can describe the multi-directional vibration energy capability of the harvester. Experiments show that the design has a large AB value (89.2◦). Furthermore, increase the output performance of the harvest by reverse series and parallel connection. Finally, a detailed study and summary of the output characteristics of all PVDFs in PVEH confirm that PVEH has potential as a vibration direction sensor. The PVEH can monitor the vibration direction of 8 areas in real-time.