JOURNAL OF ELECTROCERAMICS
·
2024
·
IF 1.7
Chen Binbin,Hu Yang,Zhang Huazhang,Chen Wen,Zhou Jing
The fatigue behavior of Bi 0.5 Na 0.4 K 0.1 TiO 3 -based ceramics depends on the polarity. While the non-ergodic relaxor ceramics have large residual polarization but poor fatigue behavior, the ergodic relaxor ceramics have excellent fatigue resistance but tiny residual polarization. Therefore, obtaining ferroelectric ceramics with high residual polarization and excellent fatigue resistance is challenging due to the trade-off between non-ergodic relaxor and ergodic relaxor. Here, we modulate the free energy barrier by doping relaxant Nb to achieve the coexistence of non-ergodic and ergodic relaxor phases. At 0.6% Nb doping, the residual polarization is large at 2 P r = 49.3 µC/cm 2 , increased to 54.23 µC/cm 2 after 10 2 cycles and decreased to 53.04 µC/cm 2 after 10 5 cycles, indicating good fatigue resistance behavior. The large residual polarization is due to the metastable ferroelectric state, while the excellent fatigue resistance may be attributed to the field-induced ferroelectric-relaxor phase transition.
研究领域:
材料科学
·
物理学
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DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2021
·Vol. 39
·期 11
·1459-1469
·
IF 3.603
Liu Yuan-Biao,Shi Gao-Peng,Wu Guo-Zhang
Introducing small molecule-bridged hydrogen bonds (HBs) between polymer chains has been reported to effectively reduce the interchain cooperativity despite of strengthening the intermolecular interaction. Here, a systematic investigation on tuning the Johari-Goldstein β ( β JG ) relaxation by adding various low-molecular-weight phenols in poly( n -alkyl methacrylate)s is carried out to further clarify the anomalous dynamics. Given these small molecules capable of coupling the motion with pendent groups of host polymers due to forming at least two HBs per molecule, poly( n -alkyl methacrylate) mixtures exhibit rich dynamic changes in the β JG -properties and α, β JG separations. An increased loading of phenols with a small size and strong inter-HB strength (Δ υ i ) clearly benefits for significant retardation and suppression of the β JG -relaxation, narrows the α, β JG separation and converges the β JG -peak with the α -peak, which demonstrates the alleviation of inter-chain topological constraints. However, small molecules with a relatively big size and weak Δ υ i are found to amplify the magnitude of the α, β JG separation of poly(butyl methacrylate), even though experimental results of changes in α -dispersion and dynamic fragility confirm a reduction of the coupling factor n in all of these hybrids. The counterintuitive phenomenon suggests that the crossover time t c in the Coupling Model is no longer a universal quantity if the inter-chain interaction of polymers is strengthened by HBs. These compelling findings shed vital insights into the HB-induced anomalous dynamics, and provide essential guidance for tailoring the β JG behavior and designing glassy polymeric materials.
研究领域:
高分子化学
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材料科学
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DOI
高影响因子
ACS Applied Bio Materials
·
2023
·
IF 4.7
Dan Zhao,Shibo Peng,Hanzhang Xiao,Qilong Li,Yahong Chai,Hongxia Sun,Ruping Liu,Li Yao,Lin Ma
Iron oxide nanoparticles (IONPs) have been developed as contrast agents for T1- or T2-weighted magnetic resonance imaging (MRI) on account of their excellent physicochemical and biological properties. However, general strategies to improve longitudinal relaxivity (r1) often decrease transverse relaxivity (r2), thus synchronously strengthening the T1 and T2 enhancement effect of IONPs remains a challenge. Here, we report interface regulation and size tailoring of a group of FePt@Fe3O4 core–shell nanoparticles (NPs), which possess high r1 and r2 relaxivities. The increase of r1 and r2 is due to the enhancement of the saturation magnetization (Ms), which is a result of the strengthened exchange coupling across the core–shell interface. In vivo subcutaneous tumor study and brain glioma imaging revealed that FePt@Fe3O4 NPs can serve as a favorable T1–T2 dual-modal contrast agent. We envision that the core–shell NPs, through interface engineering, have great potential in preclinical and clinical MRI applications.
研究领域:
生物医学工程
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材料科学
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影像医学
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DOI
PubMed
高影响因子
TALANTA
·
2023
·
IF 6.1
Zhuangzhuang Guo,Hao-ling Sun
Herein, a novel magnetic relaxation sensing strategy based on the change in Fe 3+ content has been proposed by utilizing the conversion of Fe 3+ ions to Prussian blue (PB) precipitates. Compared with the common detection approach based on the valence state change of Fe 3+ ions, our strategy can cause a larger change in the relaxation time of water protons and higher detection sensitivity since PB precipitate can induce a larger change in the Fe 3+ ion concentration and has a weaker effect on the relaxation process of water protons relative to Fe 2+ ions. Then, we employ alkaline phosphatase (ALP) as a model target to verify the feasibility and detection performance of the as-proposed strategy. Actually, ascorbic acid (AA) generated from the ALP-catalyzed L-ascorbyl-2-phosphate hydrolysis reaction can reduce potassium ferricyanide into potassium ferrocyanide , and potassium ferrocyanide reacts with Fe 3+ to form PB precipitates, leading to a higher relaxation time. Under optimum conditions, the method for ALP detection has a wide linear range from 5 to 230 mU/mL, and the detection limit is 0.28 mU/mL, sufficiently demonstrating the feasibility and satisfactory analysis performance of this strategy, which opens up a new path for the construction of magnetic relaxation sensors. Furthermore, this strategy has also been successfully applied to ascorbic acid oxidase detection, suggesting its expansibility in magnetic relaxation detection.
研究领域:
分析化学
·
生物化学
·
磁共振
·
酶测定
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DOI
PubMed
高影响因子
Materials
·
2025
·Vol. 18
·期 23
·
IF 3.2
Wenjie Zhou,Tao Du,Changbai Long
High-efficiency, lead-free dielectrics are sought for pulsed-power capacitors, yet pristine Bi0.5Na0.5TiO3(BNT) suffers from large remanence, high coercivity, and limited breakdown strength. Here, we report (1 − x)Bi0.5Na0.5Ti0.97Nb0.03O3-xSr0.85Ba0.15Ta0.5+0.02xAl0.5−0.02xO3(BNTNb–SBTA, x = 0–0.15) ceramics synthesized via solid-state reaction, achieving enhanced relaxor ferroelectric behavior through multi-cation substitution at A- and B-sites. X-ray diffraction confirms a pure perovskite solid solution, while scanning electron microscopy reveals grain refinement, suppressing oxygen vacancies and boosting the breakdown strength. Raman and dielectric analyses evidence strengthened relaxor behavior, accompanied by loop slimming and a systematic rise in breakdown strength. The composition x = 0.10 achieves the best trade-off, deliveringWrec= 3.357 J cm−3andη= 90.5% atEb= 240 kV cm−1. Robust operational stability is demonstrated with small variations ofWrec/ηover 0.1–200 Hz, 25–175 °C, and 106cycles. Pulsed tests show fast discharge (∼26 ns) withWd= 0.826 J cm−3at ∼90% efficiency under moderate fields. These results indicate that synergistic A/B-site disorder (Sr/Ba on A-site; Ta/Al with Nb on B-site), combined with microstructural densification, effectively minimizesPrwhile elevatingEb, enabling high-efficiency energy storage under practical operating conditions.
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PubMed
高影响因子
Materials
·
2022
·Vol. 15
·期 17
·5881
·
IF 3.748
Yuleng Jiang,Xiang Niu,Wei Liang,Xiaodong Jian,Hongwei Shi,Feng Li,Yang Zhang,Ting Wang,Weiping Gong,Xiaobo Zhao,Yingbang Yao,Tao Tao,Bo Liang,Shengguo Lu
Owing to the high power density, excellent operational stability and fast charge/discharge rate, and environmental friendliness, the lead-free Na0.5Bi0.5TiO3(NBT)-based relaxor ferroelectrics exhibit great potential in pulsed power capacitors. Herein, novel lead-free (1−x)(0.7Na0.5Bi0.5TiO3-0.3Sr0.7Bi0.2TiO3)-xBi(Mg0.5Zr0.5)O3(NBT-SBT-xBMZ) relaxor ferroelectric ceramics were successfully fabricated using a solid-state reaction method and designed via compositional tailoring. The microstructure, dielectric properties, ferroelectric properties, and energy storage performance were investigated. The results indicate that appropriate Bi(Mg0.5Zr0.5)O3content can effectively enhance the relaxor ferroelectric characteristics and improve the dielectric breakdown strength by forming fine grain sizes and diminishing oxygen vacancy concentrations. Therefore, the optimalWrecof 6.75 J/cm3and aηof 79.44% were simultaneously obtained in NBT-SBT-0.15BMZ at 20 °C and 385 kV/cm. Meanwhile, thermal stability (20–180 °C) and frequency stability (1–200 Hz) associated with the ultrafast discharge time of ~49.1 ns were also procured in the same composition, providing a promising material system for applications in power pulse devices.Keywords:Na0.5Bi0.5TiO3;lead-free;relaxor ferroelectrics;compositional tailoring;energy storage
研究领域:
材料科学
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能源技术
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DOI
PubMed
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2016
·Vol. 100
·期 1
·265-275
·
IF 2.787
Longwen Wu,Xiaohui Wang,Zhengbo Shen,Longtu Li
The (1− x )BaTiO 3 – x Bi(Zn 2/3 Nb 1/3 )O 3 ( x = 0.01–0.30) ceramics were synthesized by solid-state reactions. The solubility limit was determined to be x = 0.20. A systematic structural transition from a tetragonal phase ( x ≤ 0.034), to a mixture of tetragonal and rhombohedral phases (0.038 ≤ x ≤ 0.20), and finally to a pseudocubic phase ( x ≥ 0.22) at room temperature was identified. Dielectric measurement revealed a ferroelectric ( x ≤ 0.04) to relaxor ( x ≥ 0.06) transition with permittivity peak broadening and flattening, which was further verified by Raman spectroscopy and differential scanning calorimetry (DSC). Activation energies obtained from the Vogel–Fulcher model displayed an increasing trend from ~0.03 eV for x ~ 0.05, to unusually high values (>0.20 eV) for the compositions with x ≥ 0.15. With the increase in Bi(Zn 2/3 Nb 1/3 )O 3 content, the polarization hysteresis demonstrated a tendency from high nonlinearity to sublinearity coupled with the reduction in remnant polarization and coervice field. The deconvolution of the irreversible/reversible polarization contribution was enabled by first-order reversal curve distributions, which indicates that the decreasing polarization nonlinearity with the increase in Bi(Zn 2/3 Nb 1/3 )O 3 concentration could be related with the change from the ferroelectric domain and domain wall contributions to the weakly coupled relaxor behaviors.
研究领域:
材料科学
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物理学
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DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2020
·
IF 3.408
Lei Cheng,Puxuan Yan,Xiulin Yang,Huahong Zou,Hu Yang,Hong Liang
Deeply understanding the structure and electrical properties of ZIF-8 is very important due to many practical applications of porous materials . We present the crystal structure and microstructure details of ZIF-8 prepared in three different solvents. The solvents play an important role on grain growth of ZIF-8, furthermore, a small fraction of monoclinic phase can be found in the ZIF-8s prepared in water or in amonium hydroxide. Radio-frequency dielectric and impedance spectra studies of dynamic dielectric response of ZIF-8s indicate two additional dielectric relaxation processes associated with the introduced water molecules in as-prepared samples. The dielectric response can be described by the combination of the dc conductivity, the universal dielectric response, the Cole-Cole relation and intrinsic response. The results exhibit the solvents make an important influence on the electrical properties due to different contents water in ZIF-8s. Our results will pave a way to modify the dielectric property of ZIF-based dielectrics in radio-frequency applications.
研究领域:
材料科学
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电学性质研究
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DOI
高影响因子
Nanomaterials
·
2021
·Vol. 11
·期 3
·687
·
IF 5.076
Shuolei Meng,Qianyuan Chen,Hongjian Lin,Feng Zhou,Youning Gong,Chunxu Pan,Shunbin Lu
A simple and effective approach based on the liquid phase exfoliation (LPE) method has been put forward for synthesizing boron quantum dots (BQDs). By adjusting the interactions between bulk boron and various solvents, the average diameter of produced BQDs is about 7 nm. The nonlinear absorption (NLA) responses of as-prepared BQDs have been systematically studied at 515 nm and 1030 nm. Experimental results prove that BQDs possess broadband saturable absorption (SA) and good third-order nonlinear optical susceptibility, which are comparable to graphene. The fast relaxation time and slow relaxation time of BQDs at 515 nm and 1030 nm are about 0.394–5.34 ps and 4.45–115 ps, respectively. The significant ultrafast nonlinear optical properties can be used in optical devices. Here, we successfully demonstrate all-optical diode application based on BQDs/ReS2tandem structure. The findings are essential for understanding the nonlinear optical properties in BQDs and open a new pathway for their applications in optical devices.Keywords:boron;saturable absorption;fast relaxation time;all-optical diode
研究领域:
材料科学
·
光学
·
光子学
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DOI
PubMed
高影响因子
INORGANICA CHIMICA ACTA
·
2023
·
IF 2.8
Shun-Ping Zhao,Xu-lin Cui,Qiang-hong Yu,Yu Guo,Jie Wang,Heng Xu
Hybrid materials of lead halide have numerous structural variations and superior optoelectronic capabilities. The hybrid crystal 1 prepared by the hybrid halogen method has the chemical formula [ p -F-Bz-1-APy][Pb 2 Br 3.2 I 2.8 ] (C 24 H 20 F 2 N 4 Br 3.2 I 2.8 Pb 2 ) ( p -F-Bz-1-APy = p -fluoro-phenyl-1-aminopyridinium) with a space group of P 2 1 / c , two unequal [F1/F2-Bz-1-APy] + cations, and a heterogeneous double-chain inorganic layer made of edge-sharing Pb 2 Br 3.2 I 2.8 octahedron. The two cations adopt a lower-energy and more stable structural configuration, according to potential energy scans of the dihedral angles of the benzene and pyridine rings. The stacked structures are held together by a variety of intermolecular interactions, including hydrogen bonds (anion-cation, cation-cation), stacking (cation-cation), and the rare C-F2…π halo-bond. Hirshfeld surface analysis quantifies intermolecular interactions, revealing that interactions involving Br atoms and [F2-Bz-1-APy] + cations contribute more to the formation of stacking structures than interactions involving I atoms and [F1-Bz-1-APy] + cations. The logarithmic derivative method clearly reveals two dielectric relaxation processes, one in the low frequency region (<10 2 Hz) masked by the DC conductance and one in the high frequency region (10 2 -10 7 Hz), which were then fitted by the Arrhenius formula to obtain their corresponding activation energies of 77.75 KJ/mol and 144.14 KJ/mol, respectively. Our research offers inspiration and a framework for the development of novel lead halide-based optoelectronic materials and dielectric analyses.
研究领域:
材料科学
·
物理化学
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Xue Bai,Tao Fan,Gang Chen,Jie Wang,Cong Ji,Chao Chen,Zixuan Zhang,Wei Cai,Rongli Gao,Chunlin Fu
NaMg 0.12 Nb 0.88 O 3 - x BiYbO 3 (abbreviated as NMN- x BY) ( x = 0, 0.005, 0.01, 0.015, 0.02, 0.04 and 0.08) ceramics were fabricated by using a traditional solid-state reaction method. The crystal structure, morphology, relaxation behavior and energy storage properties of NMN- x BY) ceramics were systematically investigated. X-ray diffraction patterns (XRD) demonstrates that all samples present a single pseudo-cubic phase. It is also found that the grain sizes vary irregular with the BY content, and it can be reduced by the appropriate addition of BY content as indicated by scanning electron morphology. From the measured dielectric properties , it can be seen that all samples are transformed from normal ferroelectric (FEs) to relaxor ferroelectric (RFEs). The maximum relaxor diffuseness coefficient γ (∼1.78) is obtained for 0.98NMN-0.02BY ceramic. As x increases, the polarization-electric ( P - E ) hysteresis loops gradually become slimmer. The largest discharged energy density (∼0.998 J/cm 3 ) and the maximum energy efficiency (∼70%) are obtained at 170 kV/cm for x = 0.04. Meanwhile, the discharge energy densities present relatively excellent temperature stability for x = 0.02 in the temperature range from 20 to 140 °C. This work demonstrates a wide potential application in enhancing the storage properties of lead-free ferroelectric materials by co-doping MgO and bismuth-based perovskites .
研究领域:
材料科学
·
电介质物理
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DOI
高影响因子
MEDICAL PHYSICS
·
2024
·
IF 3.2
Shiman Wu,Chaochao Wang,Junjie Xia,Dijia Sun,Pu-Yeh Wu,Yue Wu,Zhenwei Yao,Yan Ren,Qi Zhang
Background The relaxivity of magnetic resonance imaging (MRI) contrast agents is primarily attributed to metal ions such as gadolinium (Gd) and iron. However, the impact of organic solutes on relaxivity, particularly through alterations in water molecule dynamics, has not been thoroughly investigated. This research was aimed to explore how organic solutes affect the relaxivities of water and Gd-based contrast agents (GBCAs), potentially revealing new aspects for the development of contrast agents. Purpose To investigate the effects of different proportions of water-soluble organic solvents mixed with pure water and GBCA on T 1 and T 2 relaxivities. Methods Ethanol, dimethyl sulfoxide (DMSO), 1,4-dioxane, glycerin, ethylene glycol, diethylene glycol, polyethylene glycol (PEG) 200, and PEG 400 were mixed with ultrapure water in various ratios (100:0, 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, 10:90, 0:100). GBCA was added to these mixtures at a concentration of 0.05 mmol/L. The mixtures underwent T 1 and T 2 mapping scans using a 3.0 Tesla MRI machine, and the relaxivities R 1 (1/T 1 ) and R 2 (1/T 2 ) were calculated and compared. Results The relaxivity R 1 of ethanol, 1,4-dioxane, and DMSO mixtures with water or GBCA, as well as R 2 of DMSO mixtures with GBCA, initially increased and then decreased. Conversely, R 1 and R 2 increased significantly with higher proportions of diethylene glycol, PEG 200, and glycerin in the mixtures with GBCA. The increase in relaxivity R 1 was correlated with greater viscosity. When the proportion of DMSO and diethylene glycol exceeded 20%, minimal variability in R 2 was observed as the water content decreased. Conclusions Adding organic solvents to water and paramagnetic relaxation reagents could alter T 1 and T 2 relaxivities, suggesting potential new directions for modifying current contrast agents. Additionally, increasing the viscosity of the contrast agent was found to enhance the relaxivity.
研究领域:
医学影像学
·
生物物理学
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DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）