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Your search keyword '"Zhang, Huawei"' showing total 177 results
Start Over Author "Zhang, Huawei" Publication Year Range Last 50 years Publisher elsevier b.v.
177 results on '"Zhang, Huawei"'

19. Polarization extension yielding ultrahigh piezoelectric response in xPb(Nb2/3Ni1/3)O3-(1-x)Pb(Zr0.3Ti0.7)O3 ferroelectrics ceramics.

Author

Wei, Yongxing, Yan, Junlong, Dong, Siyuan, Jin, Changqing, Zhang, Huawei, Hu, Lin, Nan, Ruihua, Gao, Ling, Dai, Zhonghua, Xi, Zengzhe, Jian, Zengyun, and Jin, Li

Subjects
MORPHOTROPIC phase boundaries, FERROELECTRIC ceramics, PERMITTIVITY, FERROELECTRIC crystals, PHASE transitions, TRANSITION temperature
Abstract

• The ultrahigh piezoelectric coefficient (d 33 , 1264 pC/N) reaches in the composition with x = 0.55 near the tetragonal-pseudocubic (T-PC) phase boundary. • On a local scale, electric fields do not induce phase transitions, suggesting that the exceptional piezoelectric performance in PNN-PZT stems from polarization extension near the T-PC boundary. • Both the relative permittivity and planar electromechanical coupling coefficient experience a sharp rise in the temperature range of −25 °C to 25 °C. The heightened piezoelectric performance observed in most explored perovskite systems is typically attributed to the electric-field-induced phase transition near the morphotropic phase boundary (MPB) or polymorphic phase boundary (PPB). This study, however, unveils a distinct piezoelectric enhancement mechanism in the x Pb(Nb 2/3 Ni 1/3)O 3 -(1– x)Pb(Zr 0.3 Ti 0.7)O 3 (PNN-PZT) system, diverging from the MPB/PPB-centered piezoelectric systems. Notably, the composition with x = 0.55, positioned close to the tetragonal-pseudocubic (T-PC) phase boundary, achieves an unprecedented piezoelectric coefficient (d 33) of 1264 pC/N, while retaining a tetragonal local structure. Importantly, on a local scale, electric fields do not incite phase transitions, suggesting that the exceptional piezoelectric performance in PNN-PZT stems from polarization extension near the T-PC boundary. Distinct from other mechanisms, the relative permittivity significantly increases post-poling due to this particular enhancement process. The dielectric behavior in poled specimens does not exhibit a conspicuous change at the ferroelectric-relaxor transition temperature. However, both the relative permittivity and planar electromechanical coupling coefficient experience a sharp rise in the temperature range of −25 °C to 25 °C. This investigation underscores the pivotal role of designing compositionally-driven T-PC phase boundaries, presenting a promising avenue for enhancing piezoelectric properties in ferroelectric ceramics. [Display omitted] [ABSTRACT FROM AUTHOR]

Published
2024
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22. Structure characters, and thermal evolution of electrical and elastic behaviors in xBi(Ni1/2Hf1/2)O3-(1−x)PbTiO3 solid solutions with a tetragonal-pseudocubic phase boundary.

Author

Wei, Yongxing, Zhang, Huawei, Dong, Siyuan, Jin, Changqing, Bai, Chenxing, Dai, Junle, Xi, Zengzhe, Dai, Zhonghua, Jian, Zengyun, and Jin, Li

Subjects
*SOLID solutions, *CHARACTER, *DIELECTRICS
Abstract

In this study, we synthesized solid solutions of x Bi(Ni 1/2 Hf 1/2)O 3 -(1 − x)PbTiO 3 (x BNH-PT) with the aim of elucidating their phase boundary behaviors and the associated physical properties. A tetragonal (T) - pseudocubic (PC) phase boundary was confirmed at x = 0.38. For x = 0.36 and x = 0.37 with distinct tetragonal distortions, a spontaneous ferroelectric-relaxor transition was observed. The introduction of a T-PC phase boundary not only led to enhanced piezoelectric properties (d 33 = 456 pC/N, x = 0.39) but also effectively suppressed the spontaneous ferroelectric-relaxor transition. Detailed analysis revealed that the local structure of the initial state in 0.39BNH-0.61PT remained tetragonal. After poling, a long-range tetragonal phase was formed from the short-range tetragonal clusters, with the c/a value of ∼1.01. Our observations of frequency dispersion strongly suggest the presence of local inhomogeneities, resulting in distinct poling effects on the dielectric and elastic behaviors of the material. ● The onset of a T-PC phase boundary could enhance piezoelectric properties and suppress the spontaneous F-R transition. ● The poling field promoted the formation of a long-range T phase from the short-range T clusters in 0.39BNH-0.61PT. ● The presence of the local inhomogeneities gave different poling effects on the dielectric and elastic behaviors. [ABSTRACT FROM AUTHOR]

Published
2024
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47. Air pollution governance in China and India: Comparison and implications.

Author

Wang, Pu, Liu, Dachuan, Mukherjee, Arideep, Agrawal, Madhoolika, Zhang, Huawei, Agathokleous, Evgenios, Qiao, Xue, Xu, Xiaobin, Chen, Yan, Wu, Tong, Zhu, Mengye, Saikawa, Eri, Agrawal, Shashi Bhushan, and Feng, Zhaozhong

Subjects
AIR pollution control, AIR pollution, AIR pollutants, AIR quality
Abstract

Severe air pollution in China and India threatens the health of over one-third of the global population. When it comes to air pollution governance, the two countries have vastly different approaches. China's approach features centralized target-setting and implementation, with policies enforced primarily through top-down administrative lines. While India's approach reflects the division of power among central and state governments and relies substantially on legislative and judiciary systems for accountability. We conduct a detailed review of the trends and sources of six air pollutants in China and India, and make a structured comparison of China and India's air pollution policy frameworks. An extensive literature review is conducted to evaluate the effectiveness of policies in each country. The studies show that China's policy efforts have achieved significant improvements in air quality, while India's policies have been largely ineffective. Nevertheless, both approaches have the potential to lead to effective air pollution governance, if a country can build strong political will and clearly defined accountability systems. We further identify key lessons learned from the two countries for air pollution policymaking in developing countries, including taking good advantage of "post-crisis policy window", and targeting "low-hanging fruits" to make incremental improvements in a cost-effective way. • We systematically reviewed and compared air pollution governance in China and India. • China and India have similar policy frameworks but different implementation approaches. • Strong political will and clearly defined accountability systems are key to success. • We provide insights into effective air pollution control in developing countries. [ABSTRACT FROM AUTHOR]

Published
2023
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49. Phenolic derivatives with cytotoxic activities from the roots of Fallopia multiflora var. ciliinervis.

Author

Zhang, Dongdong, Zhang, Zilong, Wu, Guoqing, Sun, Yu, Jiang, Yi, Zhang, Huawei, Song, Xiaomei, Wang, Wei, and Li, Yuze

Abstract

Fourteen phenolic derivatives including two new compounds (1, 2), one new natural product (10) and eleven known ones (3 - 9 and 11–14) were obtained from the roots of Fallopia multiflora var. ciliinervis. The structures were determined using IR, MS, 1D and 2D NMR spectroscopy and the absolute configuration of the new structure (2) was deduced by ECD experiments. All of the isolated compounds were assayed for their cytotoxic activities against three tumor cell lines (A549, HCT116 and SW620) and the results showed that compounds 12－14 showed cytotoxicities against A549 cells while compounds 10 and 11 showed cytotoxicities against SW620 cells. [Display omitted] • Two new compounds (1−2) and one new natural product (3) were isolated from the roots of Fallopia multiflora var. ciliinervis. • The absolute configuration of the compound 2 was elucidated by ECD experiments. • Compound 11 showed moderate activities against SW620 cells. [ABSTRACT FROM AUTHOR]

Published
2022
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