JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
·
2022
·
IF 3.097
Qingrong Lv,Shoujin Zhu,Xingli Zhao,Xiansong Liu,Shuangjiu Feng,Xucai Kan,Yang Yujie,Yuan Cheng
A composite material with a nominal composition of Ni 0.6 Fe 2.4 O 4 was prepared by the solid-phase reaction method. X-ray diffraction analysis shows that the product is composed of α-Fe 2 O 3 and a solid solution of Fe 3 O 4 and NiFe 2 O 4 . Although α-Fe 2 O 3 non-magnetic phase reduces the saturation magnetization, it greatly improves the temperature and frequency stability of magnetic permeability. Based on the measurement results of the amplitude permeability in the range of −60 °C to 100 °C, the temperature coefficient α μ and specific temperature coefficient β were calculated. α μ and β of the composite material are 7.15 × 10 - 5 / ° C and 8.6 × 10 - 6 / ° C , respectively, which are much smaller than α μ (1.26 × 10 - 3 / ° C ) and β (9.5 × 10 - 5 / ° C ) of NiFe 2 O 4 . At the same time, the magnetic spectrum curves show that the real part of the complex permeability μ ' basically remains unchanged within the measurement frequency range ( f < 10 6 Hz). This improvement in temperature and frequency stability is attributed to the effect of the α-Fe 2 O 3 phase.
研究领域:
材料科学
·
磁学
·
复合材料
·
固体物理
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Huan Yang,Hengtian Zhu,Hanwen Liu,Zhengyi Mao,Junxian Luo,Shugeng Zhu,Zizhong Hu,Songtao Yuan,Fei Xu
Smart contact lenses (SCLs), integrating various functional components, serve as a platform for wirelessly intraocular pressure (IOP) monitoring. Accurate and dynamic measurements offer crucial clinical references for patients with ocular hypertension. Nevertheless, the complex ocular environment poses great challenges, particularly for inductor–capacitor–resistor (LCR) type IOP sensors, which suffer signal instability due to variations of ocular dielectric properties. Here, an innovative IOP monitoring sensor with robust environmental stability, achieved by integrating the ground shield, is proposed. Employing a capacitive pressure sensor with porous polydimethylsiloxane (PDMS) structure encased in a hydrogel, the study successfully demonstrates high-sensitivity monitoring of IOP changes using in vitro porcine eyes. This optimized design empowers the wireless IOP sensor with a sensitivity of 1.15 ‰/mmHg. It exhibits exceptional frequency stability after undergoing 100 wear cycles on ten distinct porcine eyes and remains reliable across a wide range of metabolite concentrations typical of normal eyes. Notably, any observed frequency shift translates into IOP changes within a 3 mmHg range, showcasing its suitability for repeated use and daily IOP monitoring.
研究领域:
生物医学工程
·
眼科
·
传感器与执行器
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2021
·Vol. 32
·期 9
·2110478
·
IF 18.808
Liang Chen,Feixiang Long,He Qi,Hui Liu,Shiqing Deng,Jun Chen
Lead-free dielectric ceramics with ultrahigh energy storage performance are the best potential stocks used in next-generation advanced pulse power capacitors. Here, an ultrahigh recoverable energy storage density W rec of ≈7.57 J cm −3 and a large efficiency η of ≈81.4% are first realized in (Bi 0.5 K 0.5 )TiO 3 (BKT)-based relaxor ferroelectric ceramics with an ultrahigh Vickers hardness H v ≈ 8.63 Gpa by adding BaTiO 3 and NaNbO 3 in order to synergistically design the domain and microstructure in multiscale, leading to the existence of ultrasmall polar nanoregions, ultrafine grain size, compact grain boundaries, dense microstructure, and large band gap E g simultaneously. Encouragingly, an excellent energy storage temperature stability ( W rec ≈ 4.31 ± 0.25 J cm −3 , η ≈ 86 ± 5%, 20–200 °C), frequency stability ( W rec ≈ 5.14 ± 0.12 J cm −3 , η ≈ 81.3 ± 1.2%, 5–100 Hz), and excellent charge/discharge performance (power density P D ≈ 103.2 MW cm −3 , discharge energy density W D ≈ 2.4 J cm −3 , discharge rate t 0.9 ≈ 130 ns) are also achieved in BKT-based ceramics. The results demonstrate that BKT-based ceramics can be very competitive lead-free relaxors for energy storage capacitors in pulsed power devices.
研究领域:
材料科学
·
能量存储
·
陶瓷与复合材料
·
铁电材料
·
介电材料
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Wangying Xu,Tao Peng,Changjie Zhou,Deliang Zhu
Rare earth oxides (REOs) can be used as high-κ gate dielectrics that are at the core of electronic devices. However, a bottleneck remains with regard to obtaining high-performance REO dielectrics due to the serious hygroscopic issue and high defect states. Here, a general boronization strategy is reported to enhance the high-κ REO gate dielectric performance. Complementary characterization reveals that boronization is capable of reducing oxygen vacancies/hydroxyl defects in REOs and suppressing moisture absorption, leading to the improvement of leakage current, breakdown strength (up to 9 MV/cm), and capacitance–frequency stability. Furthermore, oxide transistors based on boronized REO dielectrics demonstrate state-of-the-art device characteristics with a high mobility of 40 cm2/V s, a current on/off ratio of 108, a subthreshold swing of 82 mV/dec, a hysteresis of 0.05 V, and superior bias stress stability.
研究领域:
材料科学
·
半导体器件
·
电子工程
✓ 已验证
DOI
PubMed
高影响因子
ADVANCED MATERIALS
·
2022
·Vol. 34
·期 44
·2205787
·
IF 32.086
Liang Chen,Na Wang,Zhifei Zhang,Huifen Yu,Jie Wu,Shiqing Deng,Hui Liu,He Qi,Jun Chen
Lead-free dielectric ceramics with ultrahigh energy-storage performance are the core components used in next-generation advanced pulse power capacitors. However, the low energy storage density largely hinders their development towards miniaturization, lightweight, and integration. Here, an effective strategy of constructing local diverse polarization is designed in superparaelectrics to realize an ultrahigh energy storage density of ≈10.59 J cm −3 as well as a large efficiency of ≈87.6%. The excellent comprehensive energy-storage performance is mainly attributed to the design of ultrasmall polar nanoregions with local diverse polarization configuration, confirmed by scanning transmission electron microscopy, leading to the reduced heat loss, substantially enhanced polarization, and breakdown electric field compared to ceramics with single polarization configuration. Benefiting from these features, outstanding temperature/frequency/cycling stability and superior charge/discharge performance (power density ≈187.5 MW cm −3 , discharge energy density ≈3.52 J cm −3 , discharge rate ≈77 ns) are also achieved. This work demonstrates that local diverse polarization is a super strategy to design new dielectric materials with high energy-storage performance.
研究领域:
材料科学
·
介电材料
·
储能
·
陶瓷
·
极化工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）