CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Pengpeng Xu,Junyi Yu,Chaofan Li,Suibin Luo,Shanming Ke,Yangbo Zhou,Shuhui Yu,Rong Sun
Flexible polymer composites with high dielectric constants and low dielectric losses at high frequencies are highly desired in microwave and RF applications. However, a high dielectric constant is often obtained at the expense of flexibility because a high loading of filler is needed. In this work, we synthesize a core-shell structured 1D filler by coating high-dielectric-constant PbTiO 3 onto the surface of low-thermal-expansion-coefficient SiC nanofibers , which are then incorporated into the epoxy matrix together with BaTiO 3 nanoparticles to form the multi-phase BaTiO 3 /SiC@PbTiO 3 /epoxy composite film . A high dielectric constant (35 at 100 Hz and 20 at 5 GHz) and a low dielectric loss (0.023 at 100 Hz and 0.13 at 5 GHz) are achieved as the filling content of SiC@PbTiO 3 and BaTiO 3 is 5.24 wt% and 80 wt%, respectively. Prediction models of the effective dielectric constant of polymer-based composites reveal that a continuous polarization network is constructed in the composites owing to the physical contact between BaTiO 3 and PbTiO 3 . The construction of the multi-phase filler provides a feasible way to effectively adjust and improve the dielectric properties of polymer-based composite films.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
IN VITRO CELLULAR & DEVELOPMENTAL BIOLOGY-PLANT
·
2020
·Vol. 57
·期 1
·39-47
·
IF 1.814
Wu Qinggui,Yang Honglin,Sun Yuxi,Hu Jinyao,Zou Lijuan
In vitro culture is employed as a means of producing plant materials from medicinal plants to meet the increasing demands of the market. Herein, we focused on an efficient protocol for organogenesis through two pathways in six explant types from Caryopteris terniflora Maxim ( C. terniflora ), a medicinal and ornamental plant. For direct organogenesis, the maximum number of shoots per internode explant (62.5) was achieved on Murashige and Skoog (MS) medium containing 3.0 mg L −1 thidiazuron (TDZ) and the maximum number of shoot tips per explant (45.5) was obtained by 1.5 mg L −1 TDZ, with 100% response. A protocol was also developed for indirect organogenesis from leaf, leaf-petiole, petiole, and root explants on MS basal medium containing a range of TDZ concentrations. Leaf-petiole explants induced more adventitious shoots (57.6 per explant) and leaves (31.4 per explant) than petioles (37.5 per explant) or roots (25.0 per explant), and the differentiation rate ranged from 87.2 to 100%. The regenerated shoots were elongated on MS medium containing 0.3 mg L −1 α-naphthaleneacetic acid (NAA) and 1.0 mg L −1 gibberellic acid (GA 3 ). The elongated shoots developed roots on ½ MS medium containing 0.3 mg L −1 NAA. Successful acclimatization of rooted plantlets in a greenhouse was achieved with 100% survival. Furthermore, the embryogenic-like structure was observed and the morphological characteristics of C. terniflora assessed at different stages of in vitro development. Our protocol offers, for the first time, an efficient, scalable propagation procedure for C. terniflora useful for large-scale cultivation for the purposes of conservation and genetic manipulation.
研究领域:
植物学
·
药用植物研究
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Xiuyuan Fan,Guohua Bai,Zhenhua Zhang,Xiaolian Liu,Jiaying Jin,Jiafeng Xu,Mi Yan
In this study, high-frequency MnZn ferrites are prepared for power applications at 10 MHz using solid-state reaction method. The sample doped with 3000 ppm TiO 2 yields the optimal comprehensive magnetic properties , with an initial permeability of 792, power loss of 415 kW/m 3 (10 MHz, 5 mT, 25 ℃), and saturation induction of 460 mT. This indicates significant progress compared to previously reported results. The mechanisms of property optimisation, microstructure and domain structure evolution also discussed with TiO 2 doping. The precipitation of Ti at the grain boundary can promote a high-density microstructure and favour the formation of magnetic monodomain in MnZn ferrites. Our results elucidate the correlations between microstructure, domain structure, and high-frequency performance, and present a potential roadmap for the development of high-frequency soft magnetic ferrites.
研究领域:
材料科学
·
磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2023
·Vol. 34
·期 36
·1-10
·
IF 2.8
Li Heming,Wang Xinming,Wu Tao,Gong Yuze,Zhao Hongbin,Liu Zhaobin,Dastan Davoud,Ma Ke,Hu Zhizhi
Communication industry has developed relying on technological advancement in microelectronics and large-scale integrated circuits. Modified polyimide (MPI) materials with low dielectric loss, relatively simple fabrication process, and cost-effectiveness have significant social and economic benefits. In this work, 6FAPB and 6FDA were used to polymerize fluorinated PI films by thermal imidization, and SiO 2 was used to modify PI films for further obtaining low dielectric constant ( ε )/loss (tan δ ) and enhance mechanical properties. The values of dielectric constant ( ε ) and tan δ were 2.75 and 0.00491, respectively, under 10 GHz. Meanwhile, the elastic modulus of MPI films was enhanced by the SiO 2 adding process, with a maximum tensile modulus of 2.42 GPa. The results indicate that low polarity Si–O–Si bonds lead to a decrease in overall polarity of PI films and lead to tan decrease. This work provides a simple method to increase mechanical properties and reduce the dielectric constant/loss (at 10 GHz high frequency) of PI film by introducing trifluoromethyl and SiO 2 .
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
IEEE SENSORS JOURNAL
·
2024
·Vol. 24
·期 11
·17560-17569
·
IF 4.3
Weicen Chen,Boquan Wang,Jianzhong Chen,Chenzhi You,Jing Yao,Dawei Wu
Intraluminal ultrasonic (ILUS) technology, an advanced interventional imaging technique, employs a miniaturized high-frequency ultrasound transducer mounted at the tip of a thin catheter to visualize anatomical structures within the human body. This allows for the acquisition of high-quality images of lesions in close proximity. However, existing ILUS probes predominantly offer specialized visualization in a single direction of the ultrasound catheter due to space constraints within the catheter, posing challenges to the fabrication process. In this study, an ILUS high-frequency mini-convex array probe was developed which featured 64 array elements arranged in a curvilinear configuration, providing a 90° imaging field of view. The mini-convex array was housed within a stainless-steel tube with an outer diameter of 4 mm, positioned such that its central imaging axis was oriented at a 45° angle relative to the axial direction of the tube. This configuration enabled observation of objects ahead of the catheter, even though not entirely covered, and offered detailed features of the interior configuration on its side. This probe exhibited an average center frequency, −6 dB bandwidth, and sensitivity of approximately 17.85 MHz, 61.95%, and 32.64 mV, respectively. Imaging of a wire phantom yielded axial and lateral resolutions at 5 mm depth of approximately 0.11 and 0.25 mm, respectively. Subsequently, the actual imaging capability was assessed through ex vivo imaging of the artery and esophagus of a swine, demonstrating the suitability of the high-frequency mini-convex array probe for ILUS imaging applications.
研究领域:
医学影像
·
超声技术
·
生物医学工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Ying Zhang,Jie Li,Chenqing Liao,Yang Xiao,Bing Lu,Shuai Wang,Yingli Liu,PengJie Zhang
According to this study, Co 2 Z ferrite is suitable for applications in high-frequency antennas. Ba 3 Co 2 Fe 24-x Dy x O 41 samples with different values of Dy 3+ doping concentration (x) in the range of 0.00–0.25 were prepared in the study by employing solid-state sintering and 2.5 wt% Bi 2 O 3 sintering aids. A systematic analysis of the physical phase structure, microstructure, and magnetic dielectric properties of the samples was also performed. The X-ray diffraction patterns of the samples showed that doping with Dy 3+ ions and the addition of the Bi 2 O 3 sintering aid had not changed the physical structure of the sample material, indicating that the material was still a Z-type hexagonal ferrite. In addition, according to the magnetic hysteresis loops of the samples, all six groups of them exhibited typical soft magnetic properties . With an increase in the Dy 3+ ion doping concentration, the saturation magnetization intensity and coercivity of the samples initially increased and then decreased. The sample with a Dy 3+ ion doping concentration of 0.15 had the most uniform grain distribution, largest density, and smallest porosity among the samples. Additionally, that sample had the maximum values of the real parts of the magnetic permeability (7.89) and permittivity (13.90) while having a low magnetic loss (tanδ μ ≤0.04) and a low dielectric loss (tanδ ε ≤0.03). Thus, this type of magnetic dielectric materials will have significant potential for use in high-frequency antenna applications.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2023
·Vol. 30
·期 11
·1-12
·
IF 2.8
Li Heming,Wang Xinming,Gong Yuze,Zhao Hongbin,Liu Zhaobin,Tao Lin,Dastan Davoud,Ma Ke,Hu Zhizhi,Sun Mingming
In the area of Polymer dielectric materials, those with low dielectric constant and low dielectric loss have potential to be applied in high-frequency signal transmissions, such as antennae of mobile phones and millimeter-wave radars. This study is focused on producing fluorinated polyimide (PI) film with modified organosilicon (APDS). In this work, APDS was used to PI film. The spatial hindrance of Trifluoromethyl can reduce the high frequency dielectric loss of modified PI film. The length of molecular chain was decreased as increasing the proportion of APDS, which reduced the quantity of polar imide rings in unit volume. Meanwhile, the Si-O-Si bond combination in backbone decreased the integer polarity of PI film, which resulted in the decrease of tan ?. The values of ε and tan ? were 2.48 and 0.00335 respectively under 10 GHz. The values of ε and tan? were reduced to 6.6% and 36.5% respectively compared with base membrane. Thus, this work provides a simple method to reduce the dielectric constant and dielectric loss of PI film. Meanwhile, the relationship between dielectric properties and molecular structure was proved. PI molecules were separated by low dielectric groups, which resulted in a decrease in dielectric constant and dielectric loss.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Communications
·
2024
·
IF 3.7
Bing-Jie Wang,Xing Zhang,Jian Tang,Yi-Lei Li,Mu Lan,Wen-Ning Ren,Xin Chang,Sheng-Jiang Huang,Yan Jiao,Ruo-Ding Mao,Xiao-Hui Wu,Le-Zhong Li
With the miniaturization, chip, and integration of electronic products, the working frequency of electronic components is also getting higher and higher, which puts forward requirements for us to seek high-frequency materials with higher performance. To enhance NiZnCo ferrite properties, this study introduced the rare earth element Pr for modification and thoroughly examined its impact. The material Ni 0.55 Zn 0.3 Co 0.15 Pr x Fe 2- x O 4 (NZCPF, 0 ≤ x ≤ 0.1) was synthesized by sol-gel self-propagating technique. The X-ray diffraction of NZCPF indicates that Pr 3+ doped NiZnCo ferrites still keep the cubic spinel structure. With the increasing substitution of Pr 3+ ions in NiZnCo ferrite, the average grain size of the sample decreases from 1.05 μm to 0.73 μm. After the addition of Pr 3+ ions, the dielectric loss takes its minimum value (0.41@100 Hz), and the DC resistivity ρ takes its maximum value (4×10 6 Ω·m@30℃). The value of μ' (@10 MHz) monotonically decreases from 11.9 to 5.9 as the doping amount of Pr 3+ ions, denoted by x , increases. The saturation magnetization intensity decreases from 68.05 to 58.45 emu/g, and maximum magnetic loss decreases about 30% (0.65@1 GHz). It is worth noting that the resonance frequency f r increases from 343 MHz to 638 MHz with x increases, which is a substantial improvement compared to previous studies. Generally, the introduction of Pr 3+ ions into NiZnCo ferrite results in outstanding electromagnetic characteristics, offering a valuable reference to the advancement of compact and high-frequency devices.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2025
·
IF 2.7
Hong Chen,Zhibo Huang,Qingyan Fan,Jinbao Guo
Thermotropic liquid crystalline polyarylates (TLCPs) with low dielectric loss at high frequencies have garnered significant attention due to their exceptional properties and high frequencies communication application. To investigate the influence of molecular structures on the dielectric constant and loss factor of TLCPs, 4,4′-dihydroxy diphenyl sulfone (SDP), 4,4′-dihydroxy diphenyl ether (ODP), 4,4′-dihydroxy diphenyl ketone (DHBP), and 4,4′-dihydroxy diphenyl sulfide (TDP) are introduced to copolymerize with 6-hydroxy-2-naphthoic acid (HNA) and terephthalic acid (TA) by one-pot melt polycondensation, which are defined as TLCP-I, TLCP-II, TLCP-III, and TLCP-IV, respectively. All prepared ternary TLCPs exhibit a nematic LC state between 300 and 350 °C, and the crystallinity of the modified TLCPs is reduced to a certain extent by introducing bisphenol moieties compared with the referenced polyarylate (TLCP-0) from 4-hydroxybenzoic acid (HBA) and HNA. Meanwhile, the consequent TLCPs exhibit good thermal stability, and the maximum weight loss rate temperature exceeds 500 °C. Furthermore, the initial storage modulus of TLCP-II, TLCP-III, and TLCP-IV films at room temperature are 1.2, 0.85, and 1.5 GPa, respectively, showing good tensile strength. Most importantly, the dielectric loss factors of TLCP-II, TLCP-III, and TLCP-IV are much less than 0.01 in the range of 1–10 4 kHz, thus suggesting an ideal low-dielectric-material candidate.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·Vol. 141
·期 40
·e56025
·
IF 2.7
Qingbiao Yang,Xiangyu Mei,Shuaida Shi,Kun Peng,Xiaoming Qi,M. D. Zahidul Islam,Xinyan Yang,Yinsong Si,Yaqin Fu
Ultralow- k materials with promising comprehensive performance to meet the increasing requirements of high-frequency communication are highly desired. Here, a cross-linked porous polymer SiCOH, synthesized via simple sol–gel method, was used as the filler to prepare SiCOH/PI composite films by physically blending, which demonstrates ultralow dielectric constant at high frequency. Notably, only 2.5% of SiCOH in the composite can significantly reduce the dielectric constant of PI from 3.0 to an ultralow value of 1.7 in the 9.5–12.4 GHz, together with a low dielectric loss of 0.029. Additionally, the SiCOH/PI composite maintains a high tensile strength of 82.4 MPa and a tensile modulus of 1.82 GPa, which is comparable to pure PI film. While the glass transition temperature ( T g ) increases to 370°C and the linear expansion coefficient is reduced to 30.7 ppm/°C, both of which are superior to those of pure PI film. Moreover, by introducing the hydrophobic SiCOH into PI, the contact angle of the composite films increased to 92.0°–99.0°. This simple and low-cost method not only effectively lowers the dielectric constant of PI but also improves the thermal stability, mechanical properties, and hydrophobic ability, greatly boosts the practical application of PI in high-frequency communication in the future.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF PHYSICS D-APPLIED PHYSICS
·
2023
·Vol. 56
·期 18
·185001
·
IF 3.4
Guohua Wu,Zhong Yu,Rongdi Guo,Zhiguang Wang,Hong Wang,Zhongqiang Hu,Ming Liu
To achieve compact and lightweight power conversion devices, magnetic core materials such as MnZn ferrite are highly desired with low core losses at high frequencies above megahertz. In this work, high-valent Sn4+ ions were doped into MnZn ferrite to manipulate the electromagnetic properties and suppress the high-frequency core losses. The distribution of Sn4+ in MnZn ferrite was investigated by transmission electron microscopy with energy dispersive x-ray analysis, which indicated that most of the substituted Sn4+ ions remained at the grain boundaries rather than dissolving into the lattice, and thus greatly impacted the electromagnetic properties of MnZn ferrite. The initial permeability and saturation induction decreased monotonically with the Sn substitution. The core loss was reduced to 457 kW m−3 at 3 MHz, 30 mT, and 25 °C when the Sn substitution content was 0.003, due to the effective suppression of eddy current loss and residual loss. The sample with a Sn content of 0.003 exhibited excellent overall electromagnetic properties, which could be potentially useful in high-frequency transformers, converters, and power sources.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Fang Xu,Dainan Zhang,Yulong Liao,Huaiwu Zhang
Flexible electronics is attracting widely interests for next generation electronics, especially for RF application. In this work, a flexible composite film with good magnetic-dielectric properties at high frequency was synthesized. Firstly, we prepared NiCuZn ferrite particles with uniform grains (~1.57 µm) at low temperature. Results indicated that the ferrite possessed high permeability ( μ r ′ = 472.8), low loss (tanδ μ = 0.015 and tanδ ε = 0.0063) and high saturation magnetization ( M s = 61.77 emu/g). The flexible composite films were prepared by mixing the NiCuZn particles and PDMS . The microstructures, high frequency magnetic and dielectric properties of the composite films with various NiCuZn particles were investigated. Results indicated that the NiCuZn particles not only can uniformly blend with PDMS, but also improve magnetic properties of the PDMS film at high frequency. At last, the flexible composite film possessed good magnetic properties ( μ r ′ = 2.09 and tanδ μ = 0.47) and dielectric properties ( ε r ′ = 4.43 and tanδ ε = 2.32e-2) at 1 GHz. It was indicated that the flexible film can be utilized for high frequency flexible devices. The method is also a reference for developing high frequency wearable electronic devices.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）