JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2019
·
IF 4.029
Wei Wang,Jinxing Sun,Binbin Guo,Xiaoteng Chen,K. Prem Ananth,Jiaming Bai
A high-performance piezoelectric nano-ceramic was fabricated through stereolithography of low viscosity and high solid loading ceramic/polymer composite suspensions. Through the proper fitting calculation of experimental data, the maximum theoretical solid loading, rheological and curing behaviors of the suspension system were evaluated and lucubrated. The suspensions with a 40 vol% solid loading of the BaTiO 3 nanoparticles displayed shear thinning behavior and a relatively low viscosity of 232 mPa·s at 46.5 s −1 shear rate. After post-process, the 3D printed ceramic specimens showed a nanometer-level grain size with a density of 5.69 g/cm 3 , which corresponds to about 95% of the theoretical density. The printed ceramics exhibit a piezoelectric constant of 163 pC/N and relative permittivity of 2762 respectively. The results achieved in this research indicate that the stereolithography process is a promising 3D printing technology to fabricate piezoelectric materials with complex geometries and exquisite features for the applications of ceramic components.
研究领域:
材料科学
·
制造工程
·
电子工程
✓ 已验证
DOI
高影响因子
COMPOSITES SCIENCE AND TECHNOLOGY
·
2013
·
IF 3.328
Xinzhou Wu,Zheng Chen,Zheng Cui
Albumen and BaTiO 3 nanoparticles are employed to make solution processable nanocomposite for high permittivity films. The nanoparticles are modified with poly(acrylic acid) molecules to achieve homogeneous dispersion in albumen aqueous solution and made into films by drop casting. The dielectric constant and loss tangent of albumen–BaTiO 3 nanocomposites are investigated as the function of volume fraction of BaTiO 3 . The nanocomposites exhibit maximum relative permittivity of 52 and good dielectric stability over a wide range of frequency, while the loss tangent is below 0.05 even at high BaTiO 3 loading of 80 vol%. The dielectric constants of nanocomposites with lower volume fractions (<41 vol%) are in good agreement with the Lichtenecker-Logarithmic model.
研究领域:
材料科学
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生物材料
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ELECTRONIC MATERIALS
·
2023
·Vol. 52
·期 11
·7438-7446
·
IF 2.1
Li Yingxiang,Liang Deyin,Zhang Xing,Xiong Zhe,Qing Zhenjun,Peng Sen,Tang Bin,Si Feng,Fang Zixuan,Wang Fei,Liao Tingting,Chen Jingjing
The structural characteristics and microwave dielectric properties of SrBi 2 TeO 7 ceramics intended for low-temperature co-fired ceramic (LTCC) applications were investigated. Comprehensive analyses were conducted using x-ray diffraction, structural refinement, transmission electron microscopy, Raman spectroscopy, and x-ray photoelectron spectroscopy. The findings demonstrated that SrBi 2 TeO 7 ceramics possess a pure cubic structure. Scanning electron microscopy characterizes the grain microstructure, revealing a relative density of 95.5% for SrBi 2 TeO 7 ceramic. Optimal microwave dielectric properties were achieved for SrBi 2 TeO 7 ceramics calcined at 765°C, displaying a relative permittivity ( ε r ) of 24.96, a Q × f value of 25,898 GHz ( f = 6.6 GHz), and a temperature coefficient of resonant frequency ( τ f ) of –80.7 ppm/°C. The combination of low sintering temperature and minimal dielectric loss renders these ceramics advantageous for utilization in LTCC materials.
研究领域:
材料科学
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电子工程
✓ 已验证
DOI
高影响因子
Journal of Infrared Millimeter and Terahertz Waves
·
2018
·Vol. 40
·期 1
·80-91
·
IF 1.677
Shi Zaiying,Song Lixin,Zhang Tao
The characteristics of relative permittivity and reflectance for poly (methyl methacrylate) (PMMA) films prepared by spin-coating were investigated and an excellent wideband terahertz (THz) metamaterial absorber (MA) had been fabricated by employing PMMA film as the dielectric layer. XRD and AFM indicated that all the PMMA films with thicknesses from 11 to 17 μm were amorphous and extremely smooth with roughness about 0.203 nm. Raman results demonstrated that vibration strength of the same covalent bonds tends to be consistent with an increase in film thickness. The dual beam laser interferometer (DBLI) was employed to study the influence of applied frequency and thickness on the relative permittivity, and the results exhibited dielectric constants increased from 2.88 to 4.04 with the thickness increasing from 9 to 14 μm. And the dielectric constants for PMMA films with a certain thickness (8 μm) gradually declined when the applied frequency increased from 100 to 10 5 Hz; besides, the dielectric constant in THz band was forecasted approximately 2.5. The terahertz time domain spectrometer (THz-TDS) results revealed that the THz reflectance was of gradual degradation from 80 to 58% at 3.2 THz, as the thickness increased from 11 to 17 μm. In addition, the UV-VIS spectrum showed that thickness had little effect on reflectance and transmittance in visible region, leading to the almost same E g (energy gap) about 3.7 eV. At last, by employing PMMA film as the dielectric layer, a highly wideband metamaterial absorber with absorption > 80% from 4.1 to 7.4 THz was fabricated.
研究领域:
材料科学
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光学工程
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电磁学
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纳米技术
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高分子物理
✓ 已验证
DOI
高影响因子
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
·
2024
·
IF 4.2
Xiaoqin Liu,Jianbo Liu,Wei Li,Qingqing Sheng,Yeming He,Yangyang Wang
Sol–gel method is a low-cost material preparation method; however, it is difficult to obtain a stable sol containing easily hydrolyzable metal ions via this method. In this study, a stable hafnium(IV) oxide (HfO 2 ) sol was prepared by adding benzoyl acetone (BzAcH) modifier. Infrared absorption spectroscopy results showed that the BzAcH additive chelated with the Hf 4+ ions in the sol, thus improving the hydrolysis resistance of the HfO 2 sol, which in turn improved its stability. It was also found that the BzAcH-modified HfO 2 gel film exhibited ultraviolet (UV) photosensitivity. After UV exposure, the film did not dissolve easily in organic solvents . Based on these properties, the micro processing of the HfO 2 film was preliminarily explored, and HfO 2 microstructures were successfully obtained. Additionally, the relative permittivity ( ε r ) of HfO 2 exhibited minimum (∼10.9) and maximum (∼20.6) values at heat-treatment (HT) temperatures of 350 and 450 °C, respectively. With the continuous increase in the HT temperature, ε r first decreased and then increased slightly. Moreover, the current–voltage curves showed that the Pt/HfO 2 /LaNiO 3 (LNO) structure exhibited a pronounced bipolar resistive switching (RS) effect, which was attributed to the fact that LNO could be used as an electrode and an oxygen vacancy (OV 2+ ) storage layer for RS materials. Notably, the oxygen ions in HfO 2 with a low degree of crystallinity are more likely to migrate within its body (which makes it easier to form OV 2+ s), therefore, the “Set” voltage of low-crystallinity HfO 2 films is lower than that of high-crystallinity HfO 2 films. The RS mechanism can be explained by the OV 2+ conductive filament model. These results are of great practical significance for the low-cost preparation of HfO 2 and the application of LNO as an oxide electrode.
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
ORGANIC ELECTRONICS
·
2017
·
IF 3.399
Ziyang Liu,Zhigang Yin,Shan-Ci Chen,Shilei Dai,Jia Huang,Qingdong Zheng
Insulating polymers have been recognized as a promising class of gate dielectrics for organic field-effect transistors (OFETs). However, the relative permittivity of most single polymer dielectrics is quite fixed and too low to afford low-operating voltages of OFETs. For flexible low-voltage OFETs, dielectric tunable polymer composites are highly desirable. Here, a new type of binary polymer composite dielectrics is developed by incorporating a small amount of polyacrylic acid (PAA) into poly(methyl methacrylate) (PMMA) to reduce the operating voltage and enhance the device performance. The resulting dielectric layers deliver a tunable relative permittivity from 3.32 to 4.28 with an increase of PAA contents in the composite. As results, flexible OFETs using PMMA:PAA dielectrics show greatly improved mobility and reduced threshold voltages with a low-operating voltage below −5 V. The OFETs using the composite dielectric also exhibit excellent performance stability during mechanical bending tests with different radii, where the mobility can maintain 95% of its initial value over 5000 cycles under a bending radius of 5 mm. The tunable dielectric properties and high robustness of these novel dielectrics make them promising candidates for solution-processed low-voltage flexible OFETs with low power consumption.
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 CHEMICAL THERMODYNAMICS
·
2014
·
IF 2.423
Lei Yue,Xiaomei Qin,Xi Wu,Li Xu,Yongsheng Guo,Wenjun Fang
The fundamental physical properties including density, viscosity, refractive index and relative permittivity , have been measured for binary mixtures of exo -tetrahydrodicyclopentadiene (JP-10) with four octane isomers ( n -octane, 3-methylheptane, 2,4-dimethylhexane and 2,2,4-trimethylpentane) over the whole composition range at temperatures T = (293.15 to 313.15) K and pressure p = 0.1 MPa. The values of excess molar volume V m E , viscosity deviation (Δ η ), refractive index deviation (Δ n D ) and relative permittivity deviation (Δ ε r ) are then calculated. All of the values of V m E and Δ η are observed to be negative, while those of Δ n D and Δ ε r are close to zero. The effects of temperature and composition on the variation of V m E values are discussed. The negative values of V m E and Δ η are conductive to high-density and low-resistance of fuels, which is favorable for the design and preparation of advanced hydrocarbon fuels.
研究领域:
物理化学
·
燃料科学
✓ 已验证
产品关联
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2022
·
IF 9.221
Ningyi Wang,Wei Tao,Nan Zhang,Tianshuang Wang,Xiaolong Wang,Fangmeng Liu,Xu Yan,Fengmin Liu,Xishuang Liang,Peng Sun,Geyu Lu
Microwave gas sensor (MGS), being as a kind of new-developed sensing device, possesses the ability to resolve the poor stability, imprecise selectivity, slow response speed and other problems plaguing room-temperature gas sensors. However, the nature of gas sensing mechanism of MGS has not yet been revealed, and the sensitive materials currently applied on MGS are relatively unstable and insensitive under high humidity. Here we have for the first time reported a highly sensitive, selective, and stable MGS composed of ultra-narrowband microwave filter transducer and organic-inorganic hybrid sensitive material (multilayered structured polyaniline (PANI)-SnO 2 ). Owing to the standout capacity of ammonia (NH 3 ) adsorption, the high resistance to water poisoning, and the efficient tuning of relative permittivity ascribed to p-n (PANI-SnO 2 ) heterojunction , the organic-inorganic hybrid based MGS operating at room-temperature can selectively detect low concentration of NH 3 with high sensitivity, fast response speed, and anti-humidity capacity, which has never been reported before. This work develops a new class of microwave sensing functional materials, and demonstrates that the concept in tuning relative permittivity for constructing outstanding performance microwave gas sensor.
研究领域:
材料科学
·
化学传感器
·
微波工程
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2020
·
IF 4.495
Bing Liu,Lei Li,Kai Xin Song,Min Min Mao,Zhilun Lu,Ge Wang,Linhao Li,Dawei Wang,Di Zhou,Antonio Feteira,Ian M. Reaney
LiF is a low-firing fluoride with excellent microwave dielectric properties , however densification of LiF ceramics is challenging owing to their low surface free energy. In this study, a cold sintering process (150 °C, 250 MPa, 60 min) was employed to pre-densify LiF ceramics to 78 % relative density. Post-annealing treatments between 650 °C and 800 °C led to significant grain growth which was accompanied by an increase in relative density to 92 %. The microwave quality factor ( Qf ) increased with increasing annealing temperature to a maximum of 110,800 GHz at 800 °C, 1.5 times higher than the value obtained via conventional sintering (78,800 GHz), with relative permittivity ε r = 8.2 and temperature coefficient of resonant frequency, τ f =–135 ppm/°C. Such high values of Qf and its compatibility with Ag electrode suggest that cold sintered LiF has great potential as a component or additive in low temperature co-fired ceramic formulations.
研究领域:
材料科学
·
陶瓷工程
·
微波工程
✓ 已验证
产品关联
DOI
高影响因子
IEEE Access
·
2019
·
IF 4.098
Yang Mo,Lijun Yang,Tiantian Zou,Wei Hou,Ruijin Liao
Kevlar pulp treated with low-temperature plasma and nano cellulose fibrils (NCFs) have been introduced as reinforcements in the preparation for composite insulating paper with low relative permittivity, dielectric loss, good mechanical properties, and thermal stability. More polar groups of Kevlar fibers could be exposed after plasma treatment. Results showed that the relative permittivity of the composite paper containing 20% Kevlar pulp, 10% NCF, and 70% softwood pulp is decreased by 29.6% and the dielectric loss is decreased by 43.2% at 50 Hz, 25°, compared with the conventional paper formed by pure softwood pulp. The change was due to the introduction of Kevlar pulp with intrinsic low dielectric constant and loss, which decreases the whole polarizability of the paper. The mechanical properties of the composite paper became worse after introducing 20% Kevlar pulp. About 10% NCF can work as a mechanical reinforcement to compensate for the tensile and Yang's modulus loss. Scanning electron microscopy results showed that NCF could fill the void defects and improve the interface bonding of the fibers to enhance the paper mechanical properties. The composite paper also had better insulating and thermal properties than the conventional paper. It has been concluded that the Kevlar pulp/NCF/softwood pulp composite paper has the potential to replace the pure softwood paper for the application of high-voltage ac transformer insulation.
研究领域:
材料科学
·
电气工程
·
复合材料
·
绝缘技术
✓ 已验证
产品关联
DOI
高影响因子
Nature Communications
·
2024
·Vol. 15
·期 1
·1-16
·
IF 14.7
Zhang Ruotong,Zhang Chengzhi,Fan Xiaoxue,Au Yeung Christina C. K.,Li Huiyanchen,Lin Haisong,Shum Ho Cheung
Robotics for scientific research are evolving from grasping macro-scale solid materials to directly actuating micro-scale liquid samples. However, current liquid actuation mechanisms often restrict operable liquid types or compromise the activity of biochemical samples by introducing interfering mediums. Here, we propose a robotic liquid handling system enabled by a novel droplet actuation mechanism, termed electret-induced polarization on droplet (EPD). EPD enables all-liquid actuation in principle and experimentally exhibits generality for actuating various inorganic/organic liquids with relative permittivity ranging from 2.25 to 84.2 and volume from 500 nL to 1 mL. Moreover, EPD is capable of actuating various biochemical samples without compromising their activities, including various body fluids, living cells, and proteins. A robotic system is also coupled with the EPD mechanism to enable full automation. EPD’s high adaptability with liquid types and biochemical samples thus promotes the automation of liquid-based scientific experiments across multiple disciplines.
研究领域:
机器人学
·
生物工程
·
化学工程
·
生物医学工程
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Advanced Ceramics
·
2022
·Vol. 11
·期 3
·392-402
·
IF 11.534
Feng Chao,Zhou Xu,Tao Bingjing,Wu Haitao,Huang Shifeng
Dense microwave dielectric ceramics of Ce 2 [Zr 1 − x (Al 1/2 Ta 1/2 ) x ] 3 (MoO 4 ) 9 (CZMAT) ( x = 0.02–0.10) were prepared by the conventional solid-state route. The effects of (Al 1/2 Ta 1/2 ) 4+ on their microstructures, sintering behaviors, and microwave dielectric properties were systematically investigated. On the basis of the X-ray diffraction (XRD) results, all the samples were matched well with Pr 2 Zr 3 (MoO 4 ) 9 structures, which belonged to the space group \(R\bar 3c\) . The lattice parameters were obtained using the Rietveld refinement method. The correlations between the chemical bond parameters and microwave dielectric properties were calculated and analyzed by using the Phillips—Van Vechten—Levine (P—V—L) theory. Excellent dielectric properties of Ce 2 [Zr 0.94 (Al 1/2 Ta 1/2 ) 0.06 ] 3 (MoO 4 ) 9 with a relative permittivity ( ε r ) of 10.46, quality factor ( Q × f ) of 83,796 GHz, and temperature coefficient of resonant frequency ( τ f ) of −11.50 ppm/°C were achieved at 850 °C.
研究领域:
材料科学
·
陶瓷
·
微波介电材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）