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36 results on '"Jing R"'

2. Phase Evolution and Relaxor to Ferroelectric Phase Transition Boosting Ultrahigh Electrostrains in (1−x)(Bi1/2Na1/2)TiO3-x(Bi1/2K1/2)TiO3 Solid Solutions

Author

Jing, R., Zhang, L., Hu, Q., Alikin, D. O., Shur, V. Y., Wei, X., Liu, G., Zhang, H., Jin, L., Jing, R., Zhang, L., Hu, Q., Alikin, D. O., Shur, V. Y., Wei, X., Liu, G., Zhang, H., and Jin, L.

Abstract

Owing to the complex composition architecture of these solid solutions, some fundamental issues of the classical (1−x)Bi1/2Na1/2TiO-xBi1/2K1/2TiO3 (BNT-xBKT) binary system, such as details of phase evolution and optimal Na/K ratio associated with the highest strain responses, remain unresolved. In this work, we systematically investigated the phase evolution of the BNT-xBKT binary solid solution with x ranging from 0.12 to 0.24 using not only routine X-ray diffraction and weak-signal dielectric characterization, but also temperature-dependent polarization versus electric field (P-E) and current versus electric field (I-E) curves. Our results indicate an optimal Na/K ratio of 81/19 based on high-field polarization and electrostrain characterizations. As the temperature increased above 100 °C, the x = 0.19 composition produces ultrahigh electrostrains (> 0.5%) with high thermal stability. The ultrahigh and stable electrostrains were primarily due to the combined effect of electric-field-induced relaxor-to-ferroelectric phase transition and ferroelectric-to-relaxor diffuse phase transition during heating. More specifically, we revealed the relationship between phase evolution and electrostrain responses based on the characteristic temperatures determined by both weak-field dielectric and high-field ferroelectric/electromechanical property characterizations. This work not only clarifies the phase evolution in BNT-xBKT binary solid solution, but also paves the way for future strain enhancement through doping strategies. © 2021 The Chinese Ceramic Society.

Published
2022

3. Cost-efficient decarbonization of local energy systems by whole-system based design optimization

Author

Jing, R, Hua, W, Lin, J, Zhao, Y, Zhou, Y, and Wu, J

Subjects
General Energy, Mechanical Engineering, Building and Construction, Management, Monitoring, Policy and Law
Abstract

On the way toward Net Zero 2050, the UK government set the 2035 target by slashing 78 % emissions compared to the 1990-level. To help understand how an electrified local energy system could contribute to this target and the associated cost, we develop a whole-system based local energy optimization (LEO) model. The model captures a series of state-of-the-art technologies including building fabric retrofit, battery storage, electro-mobility, electro-heating, demand response, distributed renewable, and Peer-to-Peer (P2P) energy trading. And the model enables trade-off assessment between cost and emissions minimization, compares two system operating modes, i.e., cost-oriented and grid-impact-oriented, and evaluates the impacts from weather risks and capital cost assumptions. A case study in Wales reveals (1) capital cost assumptions can lead up to 30.8 % overall cost difference of the local energy system; (2) operating the system in cost-oriented mode can save up to 5 % cost than in the grid-impact-oriented mode; (3) electro-heating by heat pumps has the highest priority among all investigated technologies. Overall, this study demonstrates how to design and operate a cost-efficient and electrified UK local energy system by the whole-system incorporation of near-term technical and business model advances towards a decarbonized future.

Published
2022

5. A comparative research on magnetron sputtering and arc evaporation deposition of Ti–Al–N coatings

Author

Li Chen, Ming J. Wu, Ke K. Chang, Jing R. Li, and Yong Du

Subjects
Materials science, Annealing (metallurgy), Metallurgy, Metals and Alloys, Surfaces and Interfaces, Sputter deposition, engineering.material, Microstructure, Titanium nitride, Evaporation (deposition), Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, chemistry.chemical_compound, Vacuum deposition, chemistry, Coating, Physical vapor deposition, Materials Chemistry, engineering, Composite material
Abstract

Ti–Al–N coating has been proven to be an effective protective coating for machining applications. Here, the differences of cubic Ti–Al–N coatings with a similar Ti/Al atomic ratio of 1 deposited by magnetron sputtering and cathodic arc evaporation have been studied in detail. Main emphasis was laid on the characterization of thermal stability and cutting performance. Both coatings during annealing exhibit a structural transformation into stable phases c-TiN and h-AlN via an intermediate step of spiondal decomposition with the precipitation of c-AlN, however, a difference in decomposition process. Compared to sputtered coating inserts, an increase of tool life-time by 42% is obtained by evaporated coating inserts at the higher speed of 200 m/min, whereas the similar cutting life is observed at the speed of 160 m/min. It is attributed to the better stability of evaporated coating due to its later structural transformation at elevated temperature. A post-deposition vacuum annealing of both coated inserts in their corresponding temperature range of spiondal decomposition improves their cutting performance due to an increase in hardness arising from the precipitation of coherent cubic-phase nanometer-size c-AlN domains. Additionally, the sputtered coating behaves in worse oxidation resistance due to its more open structure. These behaviors can be understood considering the difference in microstructure and morphology of as deposited coatings originating from adatom mobility of deposited particles, where arc evaporation technique with higher ion to neutral ratio shows higher adatom mobility.

Published
2011

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